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KITCHEN
VENTILATION SYSTEMS
BY
THOMAS E CARTER

KITCHEN
VENTILATION SYSTEMS
by
Thomas E. Carter

Copyright © 1997 by Vent Master
All rights reserved. The use of any or part of this publication reproduced, transmitted in any
form or by any means, electronic, mechanical, photocopying, recording, or otherwise stored in
a retrieval system, without the written permission of the publisher is an infringement of
copyright law.
Canadian Cataloguing in Publication Data
Vent Master
A Division of Garland Commercial Ranges Limited
ISBN 0-921501-32-3
I. Title. II. Series
Written by:
Editor:
Consulting editor:

Thomas E. Carter
A. W. Cockerill
Charlotte Brewer, M.A. (Oxon.)

Vent Master
1021 Brevik Place
Mississauga, ON L4W 3R7
Canada
Tel:
Fax:
U.S.A. to Canada:
Fax: U.S.A. to Canada:
Publishing history
First printed September 1995
Reprinted January 1996
Revised and reprinted 1997

905-624-0301
905-624-5547
1-800-565-2981
1-800-665-2438

Contents
Page
Foreword
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

Hoods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11

Grease Removal Devices . . . . . . . . . . . . . . . . . . . . . . . .

23

Ducts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

29

Air Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35

Auxiliary Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . .

45

Fire Protection Equipment . . . . . . . . . . . . . . . . . . . . . . .

55

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

61

Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

75

Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

79

Codes and Equipment Specifications . . . . . . . . . . . . . . .

105

Trouble Shooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

133

Engineered Features . . . . . . . . . . . . . . . . . . . . . . . . . . . .

141

Metric Conversion Chart . . . . . . . . . . . . . . . . . . . . . . . .

149

Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

151

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

153

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

155

Foreward
This book is for architects, engineers, kitchen designers, contractors, inspectors and others who install,
inspect, operate, maintain or service commercial kitchen ventilation systems. Its purpose is to explain
the elements of cooking equipment ventilation in plain English. It discusses four main topics:
C

The factors that shape and define a ventilation system specified by the kitchen designer;

C

Circumstances that change the selection criteria;

C

Where one type of system ends and another begins; and

C

Building codes, fire and environmental regulations that govern ventilation systems.

Contractors and service personnel will find here a concise summary of installation requirements,
operating, cleaning and maintenance procedure. The book makes frequent reference to the National
Fire Prevention Association 96 (commonly known as NFPA96) Standard, which many jurisdictions use
as a basis on which to inspect and approve kitchen installations. The influence of the NFPA 96
Standard on the layout and content of the book is readily acknowledged. Without the clear and concise
treatment the Standard gives to kitchen ventilation technology, the task of writing the book would have
been considerably more difficult than in fact it proved to be.
The book will help users avoid the costly mistakes sometimes made in choosing a ventilation system.
It should also answer many of the questions clients frequently ask architects and designers, including:
C

How can I get the most efficient system at the least cost?

C

What are the available options?

C

Where can we get expert advice without making a contractual commitment?

C

Can we exhaust to the side of the building?

C

Will a single ventilation system satisfy a multi-restaurant site?

C

Is there a generic technical specification to cover everything we need to specify in a
system?

C

What does “labelled product” mean and what’s important about it?

C

How stringently do building inspectors apply the NFPA96 Standard?

I sincerely hope that those who use the book will find sound, useful and practical advice in it to apply
to their work in kitchen ventilation technology. I purposely intended to discuss ventilation technology
in a generic sense although, admittedly with without apology, there is frequent reference to the products
of Vent Master, one of the foremost leaders in the kitchen ventilation equipment field.
Thomas E. Carter
Maplewood, NJ

Introduction

More than 5000 years ago, the Egyptians built ventilation shafts into the
pyramids to provide artisans working in the vaults and passageways with a
constant supply of cool, fresh air. Visitors to the pyramids at Giza still benefit
from the built-in ventilation system of the ancient builders when they are inside
the massive structures. Without that cooling ventilation, the atmosphere in the
dimly lit passageways and tunnels would soon become exceedingly stale and
stifling.
Good ventilation is important for the comfort of occupants in any
enclosed space. In commercial kitchens with banks of ovens, grills and fryers,
adequate ventilation is essential to deal with the effects of heat, smoke, odors,
pollutants and numerous airborne contaminants. Without adequate ventilation,
cooking operations in confined spaces would be impossible. The degree of
ventilation a given kitchen space requires depends on various factors: the type
of operation being conducted; the structure in which the kitchen operates; the
type of equipment in use; the heating source; applicable regulations and ecology
requirements.
About this book
A number of factors govern the efficiency and reliability of kitchen ventilation
systems. They include installing the right equipment for the job, good operating
practices and regular maintenance. Users will find this practical illustrated guide
helpful whether they are dealing with kitchen design, the selection of equipment, its installation, operation or servicing. It tells you the `what' and the `why'
of Vent Master equipment. Its primary purpose is to serve users as a source of
reference that neither product literature nor codes can provide.

7

How the book is organized
This book follows the pattern of chapters used in the NFPA 96 Standard
regarding chapter headings and topics within chapters. There are two reasons
for this. First, those familiar with NFPA 96 will find a logical sequence in the
treatment given to the separate aspects and parts of ventilation systems.
Secondly, for cross referencing purposes, users familiar with NFPA 96 will find
the parallel treatment of chapters and topics easy to follow.
Discussing the topics of kitchen ventilation in the same sequence as
the NFPA 96 Standard changes the way in which we cover major items of
ventilation equipment. For example, under Hoods we discuss the physical
aspects of hoods - the backshelf hood, the canopy type - and calculations for
sizing them. Airflow in and around hoods, however, is in the section dealing
with Air Flow. Similarly, separate chapters cover installation, operating and
maintenance procedures.
The treatment by topics to conform with the NFPA 96 Standard
chapters ends at the Design Section. In NFPA 96, Chapter 12 is a bibliography
under the heading Reference Publications. In our Design Section we deal with
kitchen design criteria not covered anywhere else in the book. This book also
includes three appendices and an index, which the Standard omits.
How to use it
The best way to use this manual is to know where to look for the information
you need. That is, for general information, consult the Contents page, which
lists the subject: Hoods, for example. For more detailed information, refer to
the Index, which lists topics and sub-topics in alphabetical order.
Regarding the use of abbreviations, the first time an abbreviated term or
phrase is used it is written in full, followed by the abbreviated letters given in
brackets. For example, Vent Master is followed by (VM). Thereafter, VM is
used and means Vent Master.

8

Three important words
To use this book well, understand the meaning of WARNING, CAUTION and
NOTE as used in VM shipping, unpacking, and installation procedure. They are
written for your health and safety.
A WARNING means that if you do not follow the instruction procedure
you might injure yourself or anyone working with you. VM uses a warning
notice only when there is risk to the safety of service personnel.
A CAUTION means that if you do not follow the written procedure you
might damage the equipment or component with which you are working. VM
uses a CAUTION only when there is risk of damage to the equipment or a
component.
A NOTE gives information that is useful for you to know. A NOTE is not
an instruction, but is offered to help you understand more about the equipment.
The importance of ventilation
Ventilation is the single most important factor in the design, construction and
operation of commercial kitchens. Without adequate ventilation and an ample
supply of clean air, no kitchen can operate efficiently. To ensure a kitchen is
well ventilated, the designer must consider these factors:
National, regional and local building codes are becoming increasingly more
stringent.
Environmental standards are being revised to require clean exhaust air.
Rising costs drive the industry to find innovative ways of providing competitive installation, start-up and operating solutions.

9

The sites illustrated in the examples are
typical of the ventilation problems with
which kitchen designers, renovators and
equipment suppliers can be faced. There is
no single solution for all of these problems.
We believe, however, that Vent Master has
the equipment to provide the flexibility
required to solve the problems found in the
wide variety of kitchen sites.
These are some of the kitchen ventilation
problems this book seeks to revolve. A word
in closing, however, on the kitchen equipment for which the designer must provide
sufficient ventilation.
Cooking equipment
The type of cooking operation and the equipment used has a direct bearing on
the ventilation system required. Some kitchens use more energy than others
simply because of the type of cooking done. For example, kitchens in which
grills, charbroilers and fryers are in use generate more heat than kitchens
specializing in the preparation of light meals, snacks, soups and casseroles.
Grills, fryers and charbroilers release high levels of pollutants. Ovens used
for cooking pizzas release bursts of intense heat when their doors are opened.
The hot air released by ovens, however, carries into the kitchen atmosphere
considerably less particulate matter and grease than open-top cooking.

10

Hoods

Hoods

A hood is the primary device used to collect vapors, pollutants and airborne
residues from cooking operations to funnel them into the ventilation system. The
closer the hood is to the cooking surface, the griddle plate, oven top and broiler,
the more efficiently it will collect the generated heat and particulate matter to
channel into the ventilation system. From a practical viewpoint, however, a hood
cannot be so close to the cooking surface that it hinders the kitchen staff in doing
their work.
Hood nomenclature
Over the years, a common terminology has evolved in hood types and
nomenclature. Common terms include the backshelf hood, the canopy hood,
make-up air and the abbreviations CFM, SP and FPM, as shown in Figure 7..
Make-up air means the supply of air from an exterior source to replace the air
ventilated from the kitchen.
The hood is only one component of a kitchen ventilation system, but
an important one whose size is determined by the size and capacity of the
cooking equipment being used. The capacity of the system is expressed in cubic
feet per minute (cfm). Three factors determine capacity:
1. The type of cooking appliances in use: fryers, ovens, broilers, steam
kettles, etc.
2. The type of heating source: gas, steam, electricity, or a combination of
these.
3. The barriers to air flow: building walls, fabricated enclosures.
These factors define the velocity and rate of expansion of the air in the
generated up-draft. For example, cooking appliances with large, open heated
surfaces, such as grills and broilers, create stronger up-drafts than an
11

Ventilation Systems
oven, which is built to contain the heat it uses.
Gas and solid fuel-burning appliances lose most of the energy they
produce. This waste heat generates stronger thermal currents than equipment
heated electrically or with steam.
Walls, fabricated enclosures and the type of hood used affects the volume
of exhaust air needed. Hot air rising from the cooking equipment induces the
surrounding air; i.e., the faster the hot air rises the more the surrounding air is
drawn in to replace it. Therefore the more air is required on all open or exposed
sides of the hood. Another feature of ventilation systems is that the more
enclosed the cooking operation, the less the exhaust air needed to ventilate it.
An appliance open on all sides requires a larger volume of exhaust air than
when only one side is open.
Although there are many variants of the backshelf and the canopy-type
hoods, it is the cooking equipment that determines which type of hood best suits
the application.
Figure 8 shows a low cooking surface appliance for which the backshelf
hood is well suited. The backshelf hood is sometimes called a ”low-profile
wall” or ”up-draft hood”.
A backshelf hood in close proximity to the cooking surface requires less
exhaust air than is required by a canopy hood for the same application. This
makes the backshelf hood an efficient choice for this service. The range of
clearances from the cooking surface to the top of the hood and from the floor
to the hood ducting is fairly restricted. The backshelf hood is not suitable for
tall appliances or operations that produce large volumes of smoke or steam. For
such applications a canopy hood (see Figure 9) is essential.
A canopy hood requires a larger volume of exhaust air than a backshelf
hood. Conversely, a canopy is suitable for ventilating any type of cooking
operation, its main advantage being its flexibility. By flexibility is meant that,
being open on all sides, the hood can be positioned anywhere in the cooking
space that is not adjacent to a wall. The construction of a backshelf hood
requires it to be positioned and fitted where it was designed to go. It cannot be
repositioned without modification.

12

Hoods
Exhaust air velocity
An air velocity of 50 fpm is the minimum required to contain a rising thermal
column and capture suspended particulate matter released by cooking
operations. This minimum velocity is called the “capture velocity.”
The capture velocity does more than arrest released cooking particulates.
It provides a minimum flow of air across the cooking surface to ventilate the
appliance. A velocity less than the capture velocity results in appliance
overheating problems. Higher levels can remove too much heat and cause the
cooking temperature of the appliance to fluctuate.
Calculating exhaust volumes
Once the cooking equipment layout, hood type, size and number of exposed
sides of the hood are known, calculate the required exhaust volume by adding
the lengths of the open sides, as shown in Figure 10.
The three figures combined in Figure 11 overleaf show possible
combinations of open and closed sides found in kitchen designs.
Multiply the total length of the open sides by the distance from the
cooking surface to the bottom of the hood (see Figure 12). The product in
square feet is the captive area.
Next, multiply the captive area in sq. ft. by 50 to get the captive velocity.
Finally, referring to Table 1, shown overleaf, add or subtract the cfm
correction factors according to the actual appliances in the cooking configuration.
Sizing a hood
There are three areas to consider when sizing a hood.
C

The cooking equipment layout. It is necessary to measure the length and
depth of the cooking bank. Most applications require a 6” overhang on
each side of the open cooking surface. The exception is with charbroilers,
for which a 12” overhang is used. Therefore, add 6” to each measurement
obtained and, if the hood is for a charbroiler, add 12”.

13

Ventilation Systems

W1

W2

W

Length of open sides (LT)
= L + W1 = W2

L

L
Length of open sides (LT)
=L+W

Type 1 - open sides and front

Type 2 - One side and front open
CFM correction factors
Equipment

+225

Fryers

+75

+50

Tilting skillets

+150
+150

+150
+150

Conv. broilers

+150

-

Live charcoal broilers

+350

-

Mesquite broiles

+350

-

Salamanders

Type 3 - Open front

Ovens

Figure 11 - Combination of open and
Closed sides

C

Elect.
Equip.

Broilers
Griddles

L
Length of open side (LT) = L

Gas
Equip.

+150

+50
+300

-300

+300

-200

Note: There is no correction factor for kettles,
steamers or burner ranges.

Table 1 - Correction factors

The wall locations. Determine the wall locations around the hood
perimeter. For example, if the cooking equipment is against the back wall
and in a corner, the hood would require a 6” overhang on the front of the
cooking bank and a 6” overhang on one end of the bank only.

C

The structural height limitations. The ceiling clearance determines the
height of the hood when tapers are required. For example, with a 24” high
filter hood and mounting the hood 6'6” above the finished floor line, the
top connection of the exhaust duct collar would be 8'9” above the finished
floor. Adding a 10” duct and 3” minimum clearance between the duct and
the underside of the building structure would give a required height of
9'10”. If the building structural height is only 9', the GLD hood section
would require a 10” taper.

The points to remember when sizing hoods are:
1. Hood lengths are measured in increments of 6”. Therefore, if an 8'3” long
hood is required to give a required 6” overhang, we recommend that the
hood be built at 8'6”. An 8'3” long unit would cost the same as an 8'6”
2.

dimension.
Hoods with odd dimensions can be and often are produced. For example,
14

Hoods
end walls on both sides of a hood may give a dimension of 8'5”. A
clearance of 1” should be allowed on either side to make sure the hood will
3.

fit into the space with ease. This would make the hood length 8'3”.
The standard depth of a VM hood is 4'. The smallest available depth is 3'.
If the cooking bank requires a 3'6” deep hood it is better to use a 4' deep
hood as this will increase the capture area, give improved smoke control

5.

and will not change the cfm requirements for the cooking bank.
All exhaust hoods can be tapered, but VM does not recommend a taper in
excess of 12”. Always consult the factory if special tapers are required.
When tapering an exhaust canopy, remember that it is usually mounted

6.

with the front lip 6'6” above the finished floor. There is no minimum
height code requirement, although VM recommends a minimum height of
6'3” to provide adequate working clearance and head room.
Always check the height of the cooking equipment below the hood when

4.

tapering any hood section. If a hood is tapered 12” and the hood front
mounted 6'6” above the finished floor, the back of the hood will be 5'6”
above the floor. This means that, as salamanders and cheese melters
typically stand at a height of 5'10”, they cannot be accommodated under

7.

such a hood. Instead, they would need to be wall-mounted either lower
over the cooking equipment or off to the side of the bank, requiring a 3'
extension onto the hood length.
When sizing island canopies, take into account the fact that cooking
equipment mounted back to back requires service space or a service chase
between the two banks.
An example of hood sizing for an island cooking operation is this: a
cooking bank arrangement with steam equipment on one side, heavy
duty cooking on the other, and a 12” service chase in between might
have a face-to-face dimension of between 7 and 8'. This requires a
hood of 8 - 9' depth to give the required 6” overhang. If, however, the
bank includes a charbroiler, an additional 6” is required to provide

8.

the specified 12” overhang.
For the minimum requirements, note that a single hood section can be built
to a maximum length of 16'. Beyond this length, VM banks hood sections
side by side. With this, the length of the hood section is not limited. It
could be 20' long or 100'.
15

Ventilation Systems
9.

The cooking equipment determines the dimensions of the hood. Once this
is known, the hood can be banked, tapered or custom-built to suit the
space.

Figure 13 is the section view of a kitchen
ventilation system of an actual
installation. This shows a back-to-back
arrangement of cooking equipment for
which one side requires an air flow
capacity of 150 cfm/ft. and the other 300
cfm/ft.

Canopy-filter type hoods
The canopy-filter type hood uses a UL listed grease filter to remove
contaminants from the air as it exhausts through the canopy. The filter
comprises a series of baffles that change the direction of the air flow. The
centrifugal force acting on the particles in suspension causes them to collect on
the stainless steel baffles and drop into a collection tray, as illustrated in Figure
14.
The grease collection cups in the grease trays of filter hoods need to be
emptied regularly so as not to pose a fire hazard.

16

Hoods

Terms and Conditions
Pollution contaminates the environment and decreases the purity of air, land and
water in various ways. This report is a commentary on the environmental
condition of the atmosphere as it affects commercial kitchen operations. It
explains filtration terms and conditions with which architects and kitchen
designers need to be familiar when dealing with kitchen ventilation systems.
In a healthy environmental atmosphere, the air we breathe is made up of
78% nitrogen and 21% oxygen. The remaining 1% consists of various gases and
impurities.
Figure 15 overleaf illustrates these proportions. The constituent elements
of the 1% component consist of three groups: trace gases, variable gases, and
atmospheric impurities. These are present in roughly equal proportions.
Bi-product aerosols from commercial kitchen operations can raise the
impurities present in the air above the nominal 1% value illustrated in Figure
16.

17

Ventilation Systems

The large circle of this illustration represents about 1 per cent of the air we
breathe. Three constituents make up this 1 per cent: trace gases, variable gases,
and atmospheric impurities
For striking comparison, Figure 17 shows various sizes of
aerosols in relation to a strand of human hair, which is
about 150 microns in size. Aerosols of the smallest size
(0.3 to 1 micron) such as tobacco smoke, cooking oil, and
perfumes are easily detected by one's sense of smell. The
smaller the size the higher the degree of filter or ventilation
equipment efficiency needed to deal with the aerosol.
An aerosol is a suspension of microscopic liquid or
solid particles in the air. It is the function of any kitchen
ventilation system to reduce the aerosols in a kitchen
atmosphere to a minimum.
Aerosols (or particles) are measured in microns. A
micron is one millionth of a meter (1/25,400 inch). Under SI (System
International) units of measure, micrometre is beginning to replace the word
micron. In the U.S. filter industry, micron (abbreviated Fm) is the term in
common usage.
Figure 18 is a tabulation of particle size distribution in the atmosphere.
Architects and kitchen designers will find the particulate size and element
comparison chart shown in Figure 19 a useful source of reference for a variety
of particulates. Some clients require technical specifications to cover various
types and sizes of particulates.

18

Hoods

Average particle
size (microns)

Per cent
by weight

Per cent by
particle count

Particle size
(microns)
30

20

0.005

28
10

7.5

0.175

52

5
4

0.25

11

2

1.07

6

0.5

98.5

3

3
1
0.0

Source: NAFA
"Guide to Air Filtration"

Figure 18 - Particle size distribution in atmosphere

0.01

0.1
2

3

4

5 6 7 89

1.0
2

3

4

5 6 7 89

10
2

3

4

5 6 7 89

100
2

Plant

3

1000

4

5 6 7 89

2

3

4

5 6 7 89

4

5 6 7 89

2

3

4

5 6 7 89

Pollen
Mold
Carbon black
Bacteria

Animal

Asbestos

Mineral

Coal dust
Textiles
Cement dust
Smoldering or flaming cooking oil

Combustion

Burning wood
Auto emissions
Air freshener

Home care

Humidifier
Insecticide dusts
Face powder
Copier toner

2

0.01

3

4

5 6 7 89

2

0.1

3

4

5 6 7 89

2

3

1.0

4

5 6 7 89

2

3

10

100

1000
Source: ASHREA

Figure 19 - Particle size and element comparison chart

19

Ventilation Systems
Some technical specifications specify a media velocity of something
less than the face velocity. Figure 20 shows how a pleated panel filter
achieves this reduced media velocity. Although more expensive, the
pleated panel filter is more efficient and has a longer life than an
equivalent panel filter because the media velocity can be reduced by as
much as 50% of the face velocity.
The four diagrams shown in Figure 21 illustrate various ways in
which the filter media captures particles. They show the difference
between impingement, interception, straining and diffusional effect.

20

Hoods
Terms and Definitions
Dust is dry particles of matter predominantly larger than colloidal size and
capable of temporary gas suspension. Dust is generated from the reduction of
larger, solid materials. The action of a jackhammer drilling rock creates dust;
volcanic eruptions discharge lava dust (also called ash) into the air.
Dust varies in size from <0.1 to >25 microns. Larger dust particles
settle rapidly. Smaller particles stay in suspension longer and settle more
slowly. Airborne dust under <0.1 behaves like a gas and has no rate of fall, but
is affected by Brownian movement*. This is the random movement of particles
caused by statistical pressure fluctuations over them.
Particles in the range of 0.1 to 1 micron have negligible settling
velocities. Particles in the 1 to 10 micron range have a constant and appreciable
settling rate, but are kept in suspension by air currents. Particles in excess of 10
microns settle out of the atmosphere.
Fumes are particulate matter consisting of the solid particles generated by
condensation from the gaseous state. Generally, this occurs after the volatization
from melted substances, often accompanied by a chemical reaction such as
oxidization. Arc welding fumes are typical of this chemical action. Heat from
the electric arc vaporizes some of the rod and its coating.
Fog is the condensation of water vapor in the air in sufficient concentration
to reduce visibility. This is the same phenomenon that causes clouds to form.
Mist is similar to fog except that it is the formation of liquid droplets
suspended in or falling through a moving or stationary atmosphere.
Smoke is dispersion of liquid aerosols formed by the incomplete
combustion of organic material in a gaseous atmosphere.
Gas is a phase of matter in molecular form, characterized by relatively low
density, which expands readily to fill any containing vessel.
Vapor is a gas formed by the evaporation of a material in liquid or solid
form. It is a gas at a temperature below critical temperature, so that it can be
liquified under pressure without lowering the temperature.

21

Ventilation Systems
* Brownian movement is the continuous zig-zag motion of particles (aerosols) in
suspension. The motion is caused by the impact of the molecules of the fluid (air) upon the
particles.

22

Grease Removal Devices

Grease Removal Devices

The control and removal of grease from hoods by means of grease filters, baffles
and similar devices is a subject of sufficient concern to warrant a separate
chapter in NFPA 96. The standard specifies the conditions of installation and
minimum distances between the cooking surface and the grease removal device.
Grease Extraction Rates
The National Bureau of Standards is not equipped to test ventilators.
Manufacturers test their own units according to NBS test procedure IR74-505.
This is therefore the procedure VM uses to test its Cyclo-Wash 3, Cyclo-Maze
and Cyclo-Vent units.
Although VM tested its own units to the specified NBS test procedure, it
used the services of the Institute for Storm Research to verify the tests. Dr. J.
C. Freeman, President of the Institute, has expertise in air movement,
temperature, point and factors related to condensation extraction.
The grease extraction rates of VM units, expressed as a percentage by
weight of grease removed, are on the basis of averages of a series of tests.
Filters (stainless steel baffle type GF Series)
Of the various devices available to collect and remove grease from hoods, steel
filters were for many years the most common means. The main requirements
for a filter are that it must be:
C of steel construction, tight fitting and firmly held in position;
C easily accessible and easy to remove for cleaning;
C installed at an angle not less than 45o from the horizontal;
C equipped with a drip tray pitched to drain into a container having a
minimum capacity of 0.13 gallon (0.5L).

23

Ventilation Systems
Some devices for removing grease also serve other functions, such as removal
of combustion gases, heat and cooking odors. VM has pioneered a number of
combination units, which this Section explains. For installation, operating and
maintenance procedures, refer to the relevant sections and the appendices.
Filter Grease extractor chambers (Cyclo Maze series)
There are two types of Cyclo Maze ventilators. One is a dry type; the other is
a water mist unit that uses a cold water mist to extract grease and airborne
solids, and a hot water wash for cleaning. The principle of operation for both
types is the same.
Baffles cause grease-laden air entering the plenum to move in a spinning
motion. With cold water mist nozzles, the air passes through a curtain of cold
water mist, which causes grease particles in suspension to solidify and fall into

8

7

a drainage trough or to spin off and collect on the baffle surfaces.
The high velocity flow of the air stream through a further set of baffles
removes the residual grease in suspension under the effect of centrifugal force.
The larger volume of the upper section of the plenum greatly reduces the air
velocity, causing even more grease to fall out of the air stream before it flows
through the head exhaust collar into the exhaust duct, as shown in Figure 23.

7
6

The unit operates on the principle of high capture velocities and low
5
4
1
3
2

exhaust volumes. These two features combine to provide economical grease
extraction. Baffles cause air entering the plenum from the cooking surface to
move in cyclonic motion. The centrifugal action of the air causes heavier
particles of airborne matter to collect on the baffle surfaces and drop to the
bottom surface of the plenum. Stages in the air flow through the Cyclo Maze
unit (refer to the items shown in Figure 23 and Figure 24) are:
1 The inclined face plate directs the air into the lower baffle chamber.
2 Air entering the chamber is spun in cyclonic motion.

Figure 23 - Air flow in
Cyclo Maze dry unit

3 The air then splits into two separate streams.
4 Each stream encounters separate intercepting baffles.

24

Grease Removal Devices
5 Manually adjustable baffles allow for air balancing along the length
of the hood when more than one type of cooking appliance is installed.
6 The upper chamber reduces the air velocity before it exits the pod to further
drop out grease particulates.
7 The air stream passes the exhaust control dampers used to adjust air
volumes and balance different hood sections.
8 In the final stage, the cleansed air column passes through the listed fire
damper assembly.
9 The cold water mist grease extractors are fitted with cold water nozzles to

8

7

supply a continuous stream of mist to the extractor chamber (see Figure
24). This reduces the temperature in the chamber and increases the
extraction of grease (CCM series).

7

Note

6

Three factors affect the removal of grease in exhaust hoods:

5
4
1

3
9
2

Figure 24 - Air flow in
Cyclo Maze cold water mist
unit

C
C
C

Air velocity
Change of direction and spinning thin air
Lower exhaust air temperatures

An efficient design uses a combination of one or more of these factors
throughout the path of travel of the exhaust air in the grease removal
chamber.
A good design in an extraction chamber requires a low static pressure to
operate efficiently; i.e., low internal chamber resistance allows for lower
horsepower and energy consumption to achieve maximum grease removal
efficiency.
Grease Extraction Unit as an Engine
If we recognize an engine as the energy source which makes an installation or
equipment function, we realize that the engine of a restaurant is its kitchen. In
turn, the cooking bank is the engine of the kitchen and the exhaust hood or
ventilation system keeps the cooking bank engine running smoothly.
25

Ventilation Systems
Exhaust hoods come in various shapes, capacities and styles. The grease
extractor is the engine of the hood and the main feature on which the efficiency
of the hood depends. This report is a summary of the characteristics and
specifications of hoods and their grease extraction engines.
What makes a hood engine efficient?
C Changing the direction of air to spin out grease.
C Changing the air velocity to drop out grease.
C Changing the air temperature with cold water mist to scrub and condense
out grease.
What types of engines are there?
Automobiles with which engines are most frequently associated are equipped
with four, six and eight cylinder engines, together with many features that make
them different. The same is true of exhaust hood engines.
The power of the engine lies in its capacity to remove grease. The 4
cylinder engine (2” deep) is the smallest in the range and removes the least
amount of grease. The 6 cylinder engine is larger (12” deep) and can be
manually cleaned or self cleaning using a hot water wash. The 8 cylinder engine
has a cold water mist scrubber added and, using the third grease removal
principle, removes a lot more grease. The 12 cylinder unit is the largest engine
(18” deep). It has 200% more cold water.

HOOD SECTION

"Engine"
area
The exhaust hood body is
the same as a car body.
Vent Master hoods
accommodate all engines

4 Cylinder
S/S filter

6 Cylinder
Dry extractor
with hot water
wash

6 Cylinder
Dry extractor
or removable
cartridge

8 Cylinder
cold water mist
extractor with
hot water wash

Figure 25 - Types of hood engines

26

Grease Removal Devices

27

Ventilation Systems

28

Ducts

Ducts

As part of an overall ventilation system, the ducting serves two important
functions. One is to exhaust the kitchen air to the outside environment; the
second, when replacement air is supplied through the ducting system, is to
deliver outside air to the kitchen space.
This chapter discusses the use of ducting in any ventilation system and
considerations designers, suppliers and owners need to take into account.
Here, in a general way, it is worth noting that ducting is to the system what
piping is to the water supply in that it directs the air flow from and, in some
designs, to the kitchen space. The shorter the duct run, the less power is needed
to move the air stream. In single-story structures where air is exhausted through
the roof, the size of the ducting is not critical. The run is short, the resistance to
flow negligible. In multi-story structures where the duct run length is
considerable, the designer must calculate the size of the run with accuracy.
Ducting resistance to air flow and duct length also determines the size of the
exhaust and inlet fans.
Space is the important criterion. A long, straight duct run with minimum
turns to smooth the air flow are basic to good design. There are, however, other
important factors to consider. Many codes and standards specify that ducts must
not pass through fire walls or partitions; kitchen ventilation ducts must not be
interconnected with any other ventilation ducting or exhaust system; and duct
runs must not have dips or traps in which cooking residues can collect. Openings
for access are also required, the openings clearly marked to prevent the placing
of obstructions to access.
These are some of the major considerations in the design and use of
29

Ventilation Systems
ventilation ducts, which make the ducting an important part of any system. The
applicable codes (see the Codes and Equipment Specifications Section),
provide specific detail and consultation of those considerations that apply. Here
are other important topics worth noting.
Ducts & ventilation rates
To give some idea of the cfm capacity requirements of exhaust systems, Table
3 lists cfm values used for various typical kiosk food court installations and the
hood sizes installed for food court applications.

Using the values tabulated in Table 3 for the eight kiosks, there is an average
cfm value of 17,800/8 = 2,225. It is therefore safe to work on an average value
of 2,500 cfm per kiosk, but allow for individual kiosk sizing for cfm. (See also
the Auxiliary Equipment Section.)
Openings
Access openings are required either at the sides or on the top of duct runs at
every change in direction. Hoods with dampers in the exhaust or supply collar
require an access opening for cleaning and inspection purposes. Similarly,
cleaning and inspection openings are needed for exhaust fans having duct work
connected to both sides, the opening or openings to be within 3 ft. of the fan.
30

Ducts
Duct cleaning is such an important part of maintenance that openings must
allow for cleaning the duct work along its entire length. This, in turn, means
that the system designer must make sure inspection and cleaning openings
satisfy this cleaning requirement. Kitchen ventilation is not the same as ordinary
building air conditioning ducting. Venting odors and grease vapor material can
pose fire hazards about which local and jurisdictional authority inspectors can
be and are particular.
Ducting installation
The emphasis placed on fire safety and protection by all authorities with regard
to ducting is reflected in the installation requirements of ducting seams,
penetrations and connections.
Many codes specify that duct-to-hood collar connections must have a
liquid-tight continuous external weld. NFPA 96 from which
Figure 27 is taken is specific in its requirements for connections at the hood
collar that are not continuously welded.

Duct installation clearances
A strong emphasis of NFPA 96 Standard concerns the hazardous fire
31

Ventilation Systems
potential of cooking operations. Figure 28, taken from NFPA 96 Appendix A,
shows detail to cover various types of installation requirements for a typical
commercial cooking exhaust system. Figure 28 is followed by Table 4 (also
courtesy NFPA 96 Standard) giving examples of types of construction
assemblies containing noncombustible, limited combustible and combustible
materials.
Discharge
10' 0"

Exhaust fan
Access panel
Access panel

40"

Weather-protected
opening
Roof
Not less than 1-hr fire resistance for
building less than 4 stories in height
Not less than 2-hr fire resistance for
building 4 stories or more in height
Fire-rated
floor

Access panel
Opening in enclosure
Second
story
Grease duct

Non-fire-rated ceiling
Sealed around the duct at
this point since fire-rated
floor
Exhaust hood

For SI units: 1in = 25.4 mm;
1 ft = 0.305 m
Source: NFPA 96, 1994 Edition

Figure 28 - Typical section view for building with two stories or more
with non-fire-rated ceiling and fire-rated floor

Exterior installation
Many codes, and NFPA 96 in particular, recommend that duct work be installed
vertically and adequately secured to the building exterior. The fasteners - bolts,
screws or rivets - used to secure the duct must not penetrate the duct walls.
Interior installation
As specified in NFPA 96, in buildings having more than one floor, but also in
single-story buildings with a specified fire-rated roof-ceiling assembly, ducts
have to be enclosed in a continuous enclosure to maintain the integrity of fire
separations required by the applicable building codes. The enclosure must
extend from the lowest fire-rated ceiling or floor above the hood through
32

Ducts
any concealed spaces to or through the roof.

Further, if the building is less than four stories, the enclosure wall has to have
a fire rating of not less than one hour. In buildings of more than four stories, the
enclosure fire rating has to be two hours or more.
If fire does occur in a ducting system, inspection by a qualified inspector
is necessary before further use to determine if the structural integrity of the duct
and enclosure still meets requirements for fire protection purposes.
The whole point of duct design and installation for ventilation systems is
the need to consult, and comply with, applicable code requirements.

33

Ventilation Systems

Exhaust terminations
Codes are specific for exhaust system terminations for both rooftops and walls.
For example, for rooftop terminations, NFPA 96 specifies minimum clearances
between the exhaust outlet and property lines, adjacent buildings and air
intakes as well as minimum height levels of the outlet above adjacent air intake
devices.
The requirements for wall terminations are equally specific, particularly
with respect to clearances from the outlet to adjacent buildings, power lines, air
intakes, doors and windows, etc. At no time should grease from a commercial
kitchen cooking exhaust be allowed to run down the wall of a building.
Note: Exhaust termination requirements are shown in codes as minimum
requirements. Consideration must still be given to make sure that grease build
up will not occur through roof top air intakes or in surrounding structures.

34

Air Flow

Air Flow

Every commercial kitchen requires make-up air to compensate for the air
ventilated from the kitchen space to remove heat, cooking odors and grease
created by cooking operations. Ventilation is also essential to maintain a
comfortable work environment. Make-up air can be taken from the building
HVAC system of which the kitchen area is usually a part, as illustrated in Figure
29. While this is frequently done, it is an expensive and inefficient method of
replacing exhausted air.
Quite apart from the obvious need to replace air removed from a kitchen,
inadequate make-up air will prevent the kitchen operating the way it should. Air
will be drawn in from other areas through doors and passageways.
In keeping with new requirements in kitchen ventilation, VM has introduced
a number of devices for ventilating kitchens, which include kiosk ventilation
units, air cleaning systems, water wash filter hoods with make-up air packages,
dampers for adjustable volume control and fire dampers.
The easiest situation in which to provide make-up air is in a free-standing
building of one level construction, such as found in food courts or restaurants.
The complexities of providing make-up air increase as the building in which the
kitchen operates changes from the detached, single-purpose building to the
multi-story tower structure (see the Design Section for further discussion of this
subject).
Make-up air can come from the room HVAC system, either from outlets
near to the hood or integrated into the hood. The use of cooled and heated
make-up air is expensive. For example, utility bills can double and triple. (Every
200-400 cfm of air requires one ton of A-C system capacity, which is expensive.)
Following is a summary of the devices and systems available to solve the
35

Ventilation Systems
problem of providing make-up air.
Distributing air from the ceiling near the hood with low air velocity provides
local cooling that is a necessity because of the strong radiant heat created by
cooking appliances. Increased airflows did not raise metered indicators at the
same ratio, which proves that good results in kitchen ventilation can be achieved
with careful design and efficient equipment without excessive airflows.
The following are some basic principles of commercial kitchen ventilation:
1.

Impurities and excess heat should be removed with efficient local
exhaust.

2.

Supply air should be brought to the working area in such a way
that it first refreshes workers and then replaces convective flows.

3.

Where workers are subjected to large heat radiation, supply air
should be introduced directly to the working space (local
cooling).

Down discharge supply air designs
The advantage of using integrated make-up air is that in large measure it
reduces the burden on the building HVAC systems. Make-up air is supplied
by a down discharge duct and blower close to the cooking surfaces. Three
disadvantages, however, outweigh this advantage.
1.
The air velocity from the hood supply air opening is greater

2.

3.

than that of heated air rising from the cooking surface, which
results in spillage of contaminated air held within the hood.
The lower temperature of the make-up air combined with the
greater velocity causes the air to drop rapidly, pulling
contaminant into the operator's face.
The direct down discharge can make it uncomfortable for
kitchen staff, especially in cold climates. As a consequence,
operators often shut off the make-up air system, thereby

nullifying its usefulness.
Short cycle supply air
The short cycle method of supplying make-up air provides some
36

Air Flow
untempered outdoor air within the hood enclosure to reduce the amount of air
the HVAC system must supply. This may seem to reduce the cost of using the
HVAC system, but unless the velocity of the supply air is strictly controlled
its velocity can exceed the velocity of the exhaust air and cause smoke
emission from the hood cavity.
The difference between discharging make-up air into the kitchen space
from the hood bottom front lip (Figure 30) and the short cycle method
(Figure 31) lies in the air discharge exits of the two arrangements.
In addition to the chance of emitting smoke, safety problems can arise
with short cycle hoods. In northern regions, for example, cold air can cause
frost build-up on fire protection fusible links, which effectively prevents the
links from detecting fire.
Front panel make-up air
The front panel type of make-up air (see Figure 32) is effective for virtually
all applications and climates. A perforated stainless steel plate keeps the air
flow velocity between 300 and 500 fpm. This permits the supply of a large
volume of air at the hood, with little or no effect on the kitchen environment.
The low velocity of make-up air means that it is felt only 3 to 4 feet from the
hood face.
During winter months, it may be necessary to heat the air of front panel
type make-up air (50o - 60oF is recommended). The need to cool the air during
the summer period is, however, negligible because the incoming air provides
evaporative cooling to kitchen staff working under the effect of radiant heat
generated by the cooking operation. Special consideration for some cooling may
be required in hot, humid climates.
Exhaust and make-up air limitations
If one site provides ample access for duct shafts to exhaust to the roof and
provide outdoor make-up air back to the kitchen, there are others with restricted
access. This poses problems. With no obvious solution to providing the required
air changes or to providing exhaust to the roof, and with space limitations that
make the installation of equipment difficult, the designer has many problems to
37

Ventilation Systems
overcome. A number of options are, however, available.
These are by no means the only options available for situations in which a

conventional solution to providing make-up air is difficult. The options shown
in Figure 33 illustrate that even in demanding circumstances there can be more
than one answer. The option chosen will of course depend on the particular
circumstances of each project.

38

Air Flow
Why ventilation systems are essential
Cooking produces heat, odors, smoke, vapors, airborne grease and other
pollutants, which is true of all cooking operations regardless of the type of food
preparation being done. When a ventilation system breaks down, the kitchen
atmosphere soon becomes stifling and impossible to work in. Hence, a constant
supply of fresh, clean air is essential.
The ventilation system must exhaust the heat produced and remove the
odors and pollutants. A kitchen which specializes in producing light snacks,
sandwiches and salads generates less heat and odors than kitchens producing
heavier fare: steaks, hamburgers, and French fries.
Venting cooking equipment
Gas, electric and steam cooking equipment must be allowed to breathe. Proper
air flow is required for combustion, to exhaust fumes and odors, and to prevent
moisture and heat build-up in control cabinets. Too much exhaust can suck the
heat out of an oven, preventing it from properly baking or roasting the product;
too little exhaust can cause a control cabinet to overheat and burn out expensive
equipment. Knowing what the cooking equipment requires for ventilation is
critical to its performance and operating life. If the cooking equipment does not
work properly, the kitchen will not remain in business long.
Maintaining negative pressure
The final reason why efficient ventilation is necessary is the need to maintain
negative pressure in any kitchen area. Negative pressure means drawing air into
the kitchen space atmosphere to contain the odors and pollutants that cooking
operations generate.
Kitchens operating under positive pressure force cooking odors into spaces
outside the kitchen envelope. This is unacceptable in most instances and
certainly in places of shared space: food courts, hotels, office buildings, and
even in large, stand-alone structures where the owner-operator wishes to
maintain fresh air free from excessive cooking odors in large dining
39

Ventilation Systems
areas.
Combination of equipment
The type and combination of kitchen equipment used affects the design and
capacity of the ventilation system. Deep-fryers and open ranges produce more
pollutants and continuous heat than closed ovens. When opened to remove
roasts, pizzas and baked products, ovens release waves of intense heat with
which the ventilation system must cope to maintain a stable atmosphere in the
kitchen space. The type of equipment required is one factor; the use of kitchen
space is another.
Regardless of the source of make-up air, it is necessary to calculate the
make-up air required for a given kitchen operation. This will depend on the type
of cooking being done, the equipment installed, and restrictions of the building
configuration. Some considerations to take into account when calculating the
make-up air and equipment required are:
C
C

Keep make-up air velocities to a minimum.
High velocity make-up air will disturb the capture of smoke by other
equipment.

C

Maintain a slight negative pressure in a kitchen to prevent odors and
pollutants moving from the kitchen area to other parts of the building
(a 20% negative pressure is recommended).

C

Local regulations are an important consideration and no installation
should be undertaken nor an existing operation changed without first
checking local regulatory requirements.
CFM requirements of exhaust hoods
To calculate the required exhaust air for a hood, a number of factors must be
known:
C

The cooking equipment being used, to determine where the most smoke,
grease and heat will be produced along the cooking bank.

C

The type of cooking to be done: soup and sandwich preparation; burger
and French fries cooking, fish and chip operation.
40

Air Flow
C

The hood arrangement and wall locations around the cooking equipment,
island operation, or a combination of island and wall locations.

C

The kitchen layout, to determine if there is a combination of space
restriction with a hot cooking operation.
A guide to use for estimating CFM requirements for wall-mounted hoods is:
C

For light duty equipment such as steam and ovens, use 250 CFM per
linear foot.

C

For medium-duty equipment such as fryers, griddles and restaurant series
ranges, use 300 CFM per linear foot.

C

For heavy duty equipment, charbroilers and heavy-duty equipment, use
350 CFM per linear foot.

In the majority of instances, the CFM estimates given in the guide will provide
ample air for the exhaust requirements. The guide serves for wall-mounted
canopies only. It does not serve for island applications, single cooking bank
arrangements or in cases where, say, the designer wants to know the absolute
minimum requirements.
CFM calculations for hoods
The terms used to calculate CFM values are:
Minimum exhaust cfm = Capture area x capture velocity + equipment cfm
correction factors.
Capture area = all open sides of the hood x the height above the cooking
equipment (in feet).
Capture velocity = 50 fpm (minimum.)
Equipment cfm correction factors = see Table 5 in left hand column of this
page.
A sample CFM calculation based on the elements discussed in this section is
shown in Figure 34.

41

Ventilation Systems

18'

3.5'

Broiler
Kettle

3.5'
3.5'

Range
Fryer
Fryer
Griddle

Note:
Using a rule of thumb for medium
duty cooking of 300 cfm/linear foot
of hood, the total cfm is
= 300 x 18 = 5400 cfm

16.5'
Min. exhaust cfm = (W1 + W2 + L) x H x 50 broiler + fryer + griddle
= (3.5 + 3.5 + 18) x 3.5 x 50 + (225 + 75 + 75 + 150)
= 4375 + 525
= 4900 cfm (min.)
Figure 34 - Sample cfm calculation

Velocity readings on Cyclo Maze-type hoods
To measure the average velocity on intake slots for ventilators use one of the
following formulas:
1.

2.
3.

The velocity in feet per minute (FPM),
Vol = FPM or CFM = FPM
OPN
sq.ft.area
where OPN is the total area of intake throat in sq, ft.
To find the volume in CFM,
CFM = VEL x OPN
To calculate the velocity, divide the CFM by the total opening. The
CFM or CFM/ft is information given on the U.L. label of the hood.
The standard Cyclo Wash opening is 3.5” x the length of the throat.
The total opening is 3.5” x the overall length of the intake throat.
The average throat velocity on most VM Cyclo-Maze Wash and
Cyclo Maze Dry is calculated by multiplying the design air flow
rating (shown on the ventilator nameplate) in CFM per linear ft. by
3.5. The result is the velocity in FPM.
42

Air Flow

Example
The specification is for 2250 CFM on a 9' ventilator.
OPN

VEL

= 107” x 3.5” = 374.5 sq. in.
= 374.5 = 2.6 sq. ft.
144
= 2250 = 865 FPM

2.6
For quick reference, use Table 7.
Measuring intake velocity
VM recommends the use of either an Alnor 6000 or Alnor Jr. to measure the air
velocity through the slot of Cyclo Wash and Cyclo Maze ventilators.
To measure velocity at the throat using the Alnor 6000 (see Figure 35)
position the tip of the velometer probe halfway between the inside rim and the
face of the access panel at a plane perpendicular to the air stream. Do not put
the probe too deeply into the intake throat or you will get erroneous readings.
Make sure that the hoses are of reversed polarity (+ to - and - to +) when
measuring the exhaust. Take a minimum of three readings, evenly spaced, at
each access door, then average the readings to calculate the exhaust rate.
The Alnor Jr. (see Figure 36) has a dual scale range to 1600 FPM and is
another convenient way of measuring the intake velocity. Position the velometer
as shown in the figure and take multiple readings at various points across the
length of the intake throat. Because the instrument is calibrated for use in an
upright position, expect a slight error (to 5%) on the high side. If accurate
readings are needed, use an Alnor 6000 velometer.

43

Ventilation Systems

44

Auxillary Equipment

Auxiliary Equipment

Auxiliary equipment covers those items specified as such in NFPA 96 together
with other devices or equipment not easily categorized under other references.
Typically, VM's modular utility distribution systems (MDS) discussed here are
in this category. Other devices and equipment include dampers, electrical
equipment, fans and the VM Ecoloair system.
Dampers
A common problem in large kitchens is that of air balancing and control. The
use of air volume control dampers helps. NFPA 96 does not, however, permit
the inclusion of dampers in hoods or ducts unless they are specifically listed for
such use.
Manually-operated dampers for volume control and balancing are normally
mounted before a (hood) ventilator fire damper as shown in
Figure 37. All VM ventilators are equipped with UL/ULC listed dampers. The
volume control damper can be adjustable to close off up to 50% of the outlet
duct collar area by means of locking fasteners.
Electrical equipment
Electrical equipment, wiring, and controls are for the most part governed by the
National Electrical Code as well as local jurisdictions. Specific requirements
regarding electrical devices and wiring systems in kitchen ventilation systems
are summarized:
C
C

It is not permissible to install wiring of any type in ducts.
Similarly, no electrical devices may be installed in ducts, hoods or in the
45

Ventilation Systems
path of exhaust air except where specifically approved for that use in
grease ducts. For example, they are essential in fire control and protection
devices such as fire doors.
C

Steel-enclosed lighting units mounted on the outer shell of a hood and
separated from the exhaust products by tightly fitting tempered glass and
vapor-tight seals are acceptable, but cannot be placed in concealed spaces
or cavities.

Fans
The selection of fans for ventilation systems, either to exhaust or to provide
make-up air, is an important consideration. Many types and arrangements are
available.
For typical roof top exhaust equipment and fan design improvement:
1.

Check the location and setting of the exhaust air discharge in relation

2.

to the fresh air intake as shown in Figure 38, A and B.
Check the location and setting of the exhaust air discharge in relation
to the fresh air intake as shown in Figure 39, A and B.

3.

Improve the vertical discharge velocity to disperse smoke and redirect
exhaust air away from the roof line.

4.
5.

Simplify the fan access and duct access.
Remove the need for external wire connections and pitch pockets at
the roof.
46

Auxillary Equipment
6.

Stop the build-up of water in fans during heavy rain storms and when

7.
8.

the fan is not in service.
Improve grease removal from fans during cleaning.
Stop the build-up of grease on the roof during rain storms by flushing
grease out of fan collection boxes.

9.
10.
11.
12.

Simplify installation requirements and cut the cost of installing
exhaust fans.
Provide improved access to fans for servicing.
Provide additional fire safety for exhaust discharge and the roof
structural opening.
Prevent the build-up of grease on roof tops and the A/C unit. (See
Figure 40).

Open area around entire fan
to allow slow velocity discharge & rain water inlet

Fan location
Light, aluminum construction
& access area

Exhaust air, smoke and
grease, odors

Overflow drain plug
from fan

Disconnect switch and hood-up
and external switch

Greasebox and lid

Run waterproof wiring to fan
Roof pitch pocket to seal
opening for wiring

Custom fabricated firerated roof curb

Fire-rated enclosure for
roof opening as per NFPA 96

Grease duct to go up to top of
roof curb min. 18" above roof
line as per NFPA 96

Wiring to run
outdoors to fan

Figure 40 - Exhaust equipment design features

VM’s grease exhaust roof fans are heavy duty UL\ULC units listed for 3”
clearance from combustible material. A discharge clearance of 40” above the
roof line as required by NFPA 96 eliminates discharge duct work above the
roof. This unit, shown front view in Figure 41, has removable access doors for
servicing, a pivoted fan drive section to give access to the exhaust duct, and an
average discharge velocity of 3,000 fpm as recommended by
47

Ventilation Systems
environmental authorities.
Filtration systems
The ecology filtration system of an Ecoloair unit removes 95 per cent (and 99%
as measured by ASHRAE Standard 52-68) of particulates over 0.03 microns.
This virtually means the removal by filtering of all smoke and grease, which
means that part of the odor-carrying material is removed from the exhaust.
Molecules too small to be filtered out, however, convey most of the odor. This
material is chemically treated by VM's Scentry liquid odor control solution,
which reduces cooking odors to innocuous levels.
VM rates odors for cooking operations in three categories:
C

Light: cooking a general menu for a period of 8 to 10 hours a day; covers
the operations of a small to medium-sized restaurant.

C

Medium: Small to medium-sized restaurants cooking from 12 to 16 hours
a day, preparing fragrant or pungent foods and marinades, are in this
category. If, however, the menu includes a high proportion of strong
fragrance-producing foods the restaurant should be placed in the high
odor-emission category. Similarly, restaurants that produce large volumes
of even general menu foods with short, heavy peak periods are in a
medium to high category.

C

High: This category covers large volume restaurants, hotels and 24-hour
food preparation operations using large broilers and preparing fragrant
foods for 16 hours a day or more.

Heat exchangers
Relative to make-up air systems, cooking operations require large amounts of
energy. Up to 70 per cent of the heat energy needed for cooking is exhausted to
atmosphere when drawing in make-up air and exhausting the used air.
Recovering this otherwise lost energy by means of an air-to-air heat exchanger
is possible and has obvious economical advantages in the right circumstances.
It is part of the kitchen consultant's job to include this in any kitchen planning
48

Auxillary Equipment
study. This section will help clarify the main points.
Exhaust air temperatures in the order of 85oF to 95oF at 50% RH make the
heat recovery option economic, when the air volume being considered is in
excess of 5,000 cfm. For air volumes less than this level, the energy cost saving
may not cover the cost of the equipment. These are general statements, but give
some idea of the point at which heat recovery is worth considering.
Nevertheless, since the make-up air is about 80% of the exhaust air there is
more heat in the exhaust air stream to recover, which allows a higher
temperature rise in the fresh supply air stream.
Kitchen heat recovery equipment usually handles exhaust air laden with
airborne greases given off by the cooking equipment. As this can easily plug up
the heat exchanger it is necessary to wash and clean the coil frequently.
Depending on the application, a detergent spray wash system is fitted on the
exhaust side of the unit. The frequency and duration of the spray is adjustable
to suit the particular operation.
Note: Heat pipe systems are normally used for this application as air-to-air
plate type heat exchangers are difficult to clean and maintain in greasy cooking
applications.
Another way of dealing with grease-laden air when using heat recovery
equipment is to filter the exhaust air before it enters the heat exchanger. Again,
the relative cost of this method as compared with a wash feature on the heat
exchanger requires study.
A rule of thumb to calculate savings from the installation of a heat
recovery system is $1 per cfm per year. A pay-back period of two to four years
would be the second criterion to use. To use an example, if the supply air
volume being handled is, say, 10,000 cfm, the saving in fuel costs would
amount to $10,000 per year. Applying the pay back period of three years, a
capital cost estimate of $30,000 for energy recovery equipment is an economic
investment.

49

Ventilation Systems

Modular distribution systems
An efficient and economical way of supplying utilities to commercial cooking
equipment and distributing those same services is by means of a utility
distribution unit. VM manufactures such a unit as a modular utility distribution
system, abbreviated MDS.
A MDS unit can include the utilities of gas, electrical power and controls,
hot, cold and chilled water, steam supply and condensate return, and compressed
air.
These pre-assembled units eliminate the installation and coordination of all
of the trades for piping, junction boxes conduit runs, and service wall
construction. Installation of a MDS unit requires only limited preparatory work
to bring incoming utility services for hook-up.
A big advantage of the unit is the ease with which cooking equipment can
be re-arranged to suit changed cooking operations. Quick disconnect fittings for
electrical and plumbing utilities mean that there is no need to rewire or change
the plumbing. Figure 42 shows a cut-away view of a MDS unit and lists its
main features.
Figure 42 and Figure 4.4 provide raceway and riser options of specific
MDS units.
Power supply available
120V AC through 600V AC
Single phase or 3-phase
Safety shunt trip breakers

Access panel

Isolated electrical
chase

Example
Location of branch
circuit breaker

Bus bars or
panel box

Isolated
plumbing chase

Equipment
bumper rail
Cords and plugs
or sealtite conduit
available

Branch plumbing connections
with optional quick disconnect
fittings and color-coded hoses

Figure 42 - Modular Distribution System

50

Mechanical
services available
Gas
Hot water
Cold water
Steam supply
Steam return
Chilled water
Compressed air

Auxillary Equipment
Features of the MDS
Features of the modular distribution system (see also the Engineered Features
Section) are:
C

It provides the most cost-effective method to distribute utilities in
commercial cooking operations.

C

All piping and wiring is completely enclosed in an isolated stainless steel,
300 series chassis.

C

Full function capabilities are available for gas, electric, hot water, cold
water, steam, chilled water, and compressed air services.

C

Flexibility is built into the system allowing for additions and changes.

There is safety, convenience, flexibility and efficiency in a UL/ULC
factory-built utility wall.

51

Ventilation Systems

Raceway Options
24"
(Typ)

Typical electrical
plates configuration

12"
(Typ)

A

72"

A

Space between
electrical plates

31"

MDS-GW Unit
Note: Raceways can be wall mounted
2" Gas

Breaker

6"
3/4" C.W.
Insulated

1.5"

Receptacle
28.5"

21.5"

Cord & plug

3/4" H.W.
Insulated

6"

3/4" H.W.
Insulated

Bumper strip
8"

3/4" C.W.
Insulated

1.5" Steam
insulated

MDS-GW Unit
View A-A

1.5" Gas
1" Condensate
return insulated

12"

MDS-GWS Unit
View B-B

24"
(Typ)

12"
(Typ)

12"

Typical electrical
plates configuration

B

72"

B
MDS-GWS Unit

24"

Figure 43

52

Auxillary Equipment
Riser Options
for MDS-GW & MDS-GWS Units

72"

72"

(Recommended)

(Recommended)
Electrical

Electrical
& plumbing

Pedestal

Plumbing

MDS-GW-EL/PR

MDS-GW-EPR

72"

72"

(Typical)
Electrical
& plumbing

(Special)
Plumbing

MDS-GWS-EPL/PR

Electrical
& plumbing

MDS-GWS-EPL/EPR

Figure 44 - Riser options

53

Electrical
& plumbing

Ventilation Systems

Kiosk Ventilation System
The Kiosk Ventilation System (KVS) is a recirculating air unit that was
developed for kiosk-type food court operations and non-traditional sites where
NFPA 96 duct work either cannot be installed or would be difficult to install.
The KVS unit can be a right hand (RH), left hand (LH), Back (B) or
remote mount (REM). The size of a unit depends on the CFM delivered and
ranges from 1100 cfm to 2250 cfm.
To select a particular size of KVS unit, the designer needs to know the type
of cooking equipment installed in a given kitchen and its size. Types of cooking
equipment are summarized in Table 8 following.

Note 1: There are three VM KVS models available. These are the KVS-5,
the KVS-6 and KVS-8. Referring to the table of cooking equipment, a KVS-5
can satisfy a cooking load for a maximum of 2 appliance; a KVS-6 for 3
appliances; and a KVS-8 for 4 appliances. See also the Codes and Specifications
Section.
Note 2: A recirculating hood system must meet the requirements of NFPA
96, Chapter 10 and be tested and listed as per U.L. 197-1994 for integral
recirculating systems for commercial electric cooking appliances. A clean air
EPA 202 test must also be passed using the specific cooking equipment being
used with the system.

54

Fire Protection Equipment

Fire Protection Equipment

Fire protection and control is an integral part of any kitchen ventilation system.
The subject is specifically addressed in the NFPA Standard, which requires fire
extinguishing equipment for the protection of grease extraction devices and
cooking equipment. NFPA 96, however, is not the only standard local regulatory
authorities apply to commercial kitchen systems.
Automatic fire extinguishing systems are an increasingly common feature
of modern kitchen ventilation systems. Indeed, most codes require that automatic
fire protection systems form part of the ventilation system. This system must not
only provide fire protection, but also automatic disconnection of the fuel supply
to the cooking equipment if a fire occurs.
The three primary types of fire protection systems are dry chemical, wet
chemical and water sprinkler, which are summarized here.
Dry chemical systems
The chemical most often used in a dry system is a sodium bicarbonate based
material. In this type of system, the chemical suppresses the flame and reacts
with the grease to form a foam, which prevents the grease and vapors from
escaping to the atmosphere. The dry chemical system is being replaced by the
more efficient and cost effective wet chemical system and will soon be removed
from the field for new installations.
Wet chemical systems
In contrast, wet chemical systems most commonly use a potassium carbonate,
potassium acetate, or CO2 based formulation. The wet chemical is similar to the
action of dry chemical in suppressing the flame and preventing or retarding the
escape of grease vapors to the atmosphere.
Both wet and dry chemicals are effective fire extinguishing agents, but
both have several disadvantages. The most obvious is that, following
55

Ventilation Systems
activation and suppression of the fire, the cooking line requires thorough
cleaning to restore it to an operating condition. As a result, the down time can
be lengthy. Also, to conform to fire regulations, the chemical agent must be
replaced before a resumption of cooking. If a reflash occurs, there is no agent
left to discharge a second time. Also the system discharges all at once over the
entire cooking bank.
Water sprinkler systems
A water mist sprinkler installation is a preferred means of providing fire
protection in a kitchen. Water mist sprinkler systems are easily interconnected
to a building's sprinkler system. A fire detecting element fitted in each of the
system's nozzles guarantees that water comes from an activated nozzle only.
Once the fire is extinguished, the water supply is easily shut off by means of the
hand operated valve in the control cabinet.
Once activated and the fire suppressed, clean-up is quick, easy and
simple with, as a consequence, a minimum down time of the cooking line.
The general requirements for fire suppression systems are:
C

The system is to be connected to the building sprinkler system.

C

The minimum water pressure at the control cabinet must not be less than
40 psi.

C
C

The maximum pressure at the cabinet must not exceed 175 psi.
If the authority having jurisdiction accepts a water pressure greater than
175 psi, the contractor responsible for the sprinkler installation must
supply and install an approved pressure reducing valve.

C

The minimum water flow required in gpm will depend on the pipe size of
the system. Refer to the pipe size chart -

C
C

Table 9.
The size of pipe required is determined by the number of nozzles (see
Table 10 in the Installation Section).

Figure 45 shows a general arrangement for a water sprinkler system and
specifies basic elements such as pipe size limitations.

56

Fire Protection Equipment
Pipe
size
1"
1 1/4"
1 1/2"
2"

Nozzles Min
Max.
Nozzles Disch. GPM
8
12
20
30

2
4
6
8

15
30
45
75

1 1/4" Min. pipe size for ventilators rquiring plenum and
duct collar protection

Model
No.
SU3-100
SU3-125
SU3-150
SU3-200
No. of
nozzles on
system

Table 9 - Pipe size chart

Piping and wiring connections
between control panel, hood
and cooking equipment by services
other than the equipment supplier

Size of sprinkler piping
determined by the
number of nozzles
(1" min - 2" max.)

Inspection test valve
Manual air vent

Wiring to building fire
alarm monitoring system
if so equipped
120V power supply
Sprinkler head nozzles
Number required will
depend on cooking
equipment.

Water supply from
building sprinkler system

Connections for water wash
control panel and fire stat.
relay if a water-wash hood
is installed

Water-mist control panel
Surface or recessed
mounting

Warning lights & alarm horn
Green "Power On"
Green "System operational"
Amber "Low water pressure"
Amber "Hand valve open"
Red "Fire alarm"

Figure 45 - Water-Mist protection system

57

Space occupied by
cooking equipment
per project specifications
(supplied by others)

Ventilation Systems
Surface fire protection
The number of nozzles required in a fire suppressor system depends, of course,
on the variety and number of items of cooking equipment.
VM calculates the number of nozzles required and designs each system to
meet the cooking bank lay-out requirements.
Nozzles
The sprinkler nozzle is an important part of any fire protection system. Table
10 (see the Installation Section) gives hydraulic data based on the size of
piping and number of nozzles in a system.
For installation, nozzle settings and related information, refer to Figure 47
in the next section, Installation.
Fire dampers
There is considerable divergence of opinion among various code authorities,
inspectors, engineers, consultants and manufacturers on the need for and
effectiveness of fire dampers in commercial cooking exhaust hoods.
There are two bodies of opinion on the use of dampers. The first is that
U.L. listed and properly installed dampers can contain a fire and that the
mechanism will not permit the ambient air temperature in the exhaust duct work
to rise above 365oF. This parameter is established under U.L. Standard 710 and
VM products listed under this evaluation have passed this requirement. Here the
intent is to contain a fire within the hood or a portion of the exhaust duct work
to avoid transfer of the fire into adjoining areas of the building. This minimizes
fire damage and is some insurance against loss of life, particularly in
multi-story buildings.
The second body of opinion is to install exhaust systems and not to permit
a damper of any kind, so as to allow the fire and smoke to escape through the
exhaust duct to give building occupants more time to leave the building. This
approach relies strictly on the construction of the duct, the rated duct shaft
enclosure, and the ability of the building to contain the fire until it is
extinguished. The principle behind this approach is that loss of life occurs
through smoke inhalation much sooner than by any fire in a building.
58

Fire Protection Equipment
Manufacturers of fire extinguishing systems recommend that the fire
suppressant agent be drawn through the duct work to help choke any fire, which
suggests the non-damper approach to dealing with the outbreak of fire.
Nevertheless, a U.L. listed hood can serve its function (that is, having the
damper mechanism operate) and still allow the fire suppressant chemical to
disperse in the duct work beyond the damper as well.
The VM fire damper (see Figure 46) uses a fusible link to actuate the
movement, not electrical power. This means the damper will operate even if the
electrical power is lost. The hood and fusible link damper has been approved
by Factory Mutual Research and is listed as a fire barrier by the New York
Board of Standards and Appeals.
This use of fire dampers is substantiated by NFPA Bulletin #96 to permit
the use of dampers if specifically listed as such or when part of an approved
system.
VM's opinion on the use of dampers is that listed products are the best
insurance of safety and reliability. When a system incorporates a non-damper
arrangement, the construction of the exhaust duct work and duct enclosure
becomes considerably more important.
When fire occurs and the extinguishing system fails, dampers can control
fire, allow more time for people to evacuate the kitchen, and give a measure of
protection to the rest of the building until outside fire fighters arrive. In short,
an investment in proven products that exceed the minimum requirements of
codes ensures safety to the owner and employees.
Listed grease extractors
National fire codes have for many years included provision for the use of ”listed
grease extractors”. Recognizing the extensive fire severity testing performed on
listed equipment, fire codes grant specific exceptions regarding the fabrication
and installation of water wash grease extractor hoods.
Fire severity tests performed under U.L. Standard 710 evaluate the
ability of the ventilator to contain a surface fire beneath the hood canopy. One
test requires that the exhaust plenum and 36” of the connecting grease duct be
coated with 0.3 lbs of grease per sq. ft. of the interior surface. Subjected to a
surface fire, the plenum grease is allowed to ignite. For the duration of
59

Ventilation Systems
the test there may be no separation of seams or undue buckling of the unit. No
flames or temperatures in excess of 375oF may enter the exhaust duct at any
time.
The U.L. test is conducted without the use of water, the assumption being
that a fire could render the water wash function inoperable. For this reason, the
U.L. listing does not require the grease extractor to go into a ”wash down”
mode during a surface fire.
Fire marshals, building inspectors and specifiers in some areas do require
that the wash function be energized simultaneously with the fire protection
system. There are several ways of achieving this function. They are:
1 Specify a control panel that interconnects to the fire protection panel. When
it is specified, VM adds a ”firestat relay” to the control panel. Wired in the
field, the relay allows an external control circuit to energize the wash timer.
(Specify 120V AC, 24V AC, or 24V DC.)
2 Specify a microswitch option with the fire protection system. This will be
supplied with the unit for installation by the fire protection or electrical
contractor.
3 Specify that the electrical contractor provides a separate control circuit
(120V AC unless otherwise specified) to the fire protection panel. From
there the contractor should provide a 2-wire service to the ventilator control
panel and the cooking equipment disconnect.
For detail regarding the inter-connections between the ventilator control panel
and the fire protection panel refer to the Installation Section under Listed
grease extractors, electrical controls.
Automatic duct protection
Fire protection of ducts equipped with dampers is by means of fusible links that
monitor the exhaust temperature at the duct collar. Rated to activate at 280oF,
the fusible link will cause the damper to close.

60

Installation

Installation
ECOLOAIR™ INSTALLATION INSTRUCTIONS
AND DESIGN REQUIREMENTS

Clients, kitchen consultants and general contractors install equipment using
personnel other than those available from the equipment supplier. In those
instances, and to guide those who might be required to install Vent Master
Ecoloair Filtration Systems, we offer these mechanical and electrical
installation procedures.
Mechanical:
Make sure that the exhaust duct work installed between the ventilator and the
Ecoloair unit conforms to the NFPA 96 Standards.
All duct work downstream of the Ecoloair unit fire damper shall conform to the
applicable ASHRAE guidelines and local codes.
C

All duct connections to the unit must be transitioned to the full opening at
the unit inlet and outlet openings.

C

All duct work between the ventilator, the Ecoloair unit, and downstream
of the unit is by others.

C

Maintain a minimum 30” clearance on the access panel side of the unit for
servicing and replacement of the filter.

C

Install the filters in the correct sequence (see the Section on Grease
Removal Devices) and make sure the panels are properly seated against
the filter support frame.

C

Remove the fan spring isolator hold-down brackets before starting the
exhaust fan. The brackets are used for shipping purposes only. When the
brackets are removed, the exhaust fan should float freely on the spring
isolators. Make sure the fan does float freely.
61

Ventilation Systems
C

A qualified structural engineer should verify that the structure will support
the additional load and provide the qualification details. This applies to all
applications: roof mounted, ceiling suspended or any other form of
mechanical structural support.

C

Provide suspended units with a service platform along the entire length of
the unit. Service platforms supplied by others should provide a minimum
clearance of 30” for servicing access as specified for replacing the filter.

C

Maintain a minimum clearance of 6” between modular units when they are
mounted piggy-back.

Electrical
Connect the incoming 3-phase, 60 cycle power supply to the main disconnect
of the fan starter of the exhaust fan section.
Caution
The electrical power rating shown on the control panel will determine the size
of the power cable, which must conform to the applicable electrical codes.
C

For particular installations, refer to the wiring diagrams included in the

package of shop drawings shipped with the unit and make the following
electrical connections. (Additional copies of shop drawings are usually
available on request.)
Note
Use 120V 14 gauge (min.) AWG wire for control wiring connections between
panels. It is, however, necessary to check that wiring used for field connections
conforms to the applicable local electrical codes.
C

Through conduit run between the exhaust fan cabinet panel and the
pressure sensor enclosure on the filter section, make the control wire
connections as shown on the wiring diagram supplied.

C

Make the wiring connections through appropriate conduit between the
exhaust fan cabinet and the Ecoloair control panel as shown in the wiring
diagram.

C

Connect the utility terminals in the enclosure panel to the numbered
terminals in the Ecoloair control panel.

C

Connect the field wiring from the Ecoloair control panel to the ventilator
control panel or disconnect switch, whichever is applicable as shown
62

Installation
on the wiring diagram.
C

If the installation includes an optional Energy Reclaim Section, connect
the field wiring between the exhaust fan cabinet panel to the energy
reclaim section supply fan, making the connections between corresponding
numbered terminals as shown on the wiring diagram.

Sound levels
Workers and the general public are becoming increasingly concerned with noise
pollution in all its forms: blaring radios, Musak systems, loud machinery,
engine noises, aircraft near airports. Conscious of the need to eliminate
unnecessary noise in its equipment, VM has designed its Ecoloair system for a
smooth-running minimum noise operation and has available acoustic insulation
options; (consult the factory if required).
FIRE SUPPRESSOR SYSTEMS INSTALLATION
INSTRUCTIONS AND DESIGN REQUIREMENTS
Some local codes and regulations may not permit connection to the building
domestic water system. This needs investigating. If the connection is not
approved, operation of the fire suppressor system might trip the low water
pressure switch, shut down the equipment, and register an alarm. The water
pressure must be constant and uninterrupted.
Sprinkler nozzles
The positioning and setting of sprinkler nozzles varies from one type of cooking
equipment to another. Particular features follow for each type of ventilator or
item of cooking equipment. Table 10 is a nozzle temperature rating chart.
Canopy ventilator
Figure 47 illustrates the important setting and positioning features of sprinkler
nozzles in the canopy drop ventilator. Accurate leveling and positioning of the
nozzle frame below the lower edge of the ventilator face is essential.

63

Ventilation Systems

Install a VM fire suppressor system by following this general procedure,
making sure there is compliance with all local codes, ordinances and
regulations.
Electrical
Connect a 110V AC single phase power supply to terminals noted in the control
panel wiring diagram. For terminal connections to the cooking equipment
shutdown device (not supplied by VM), for 120V AC connections to the
waterwash control panel (but omit if the ventilators are filter-type hoods), and
for a signal line from the suppressor panel to the building fire alarm monitor
circuit, refer to the control panel wiring diagram.

64

Installation

Plumbing
Piping for the suppressor manifold is sized according to the number of nozzles
required. The suppressor system, complying with the requirements of NFPA 13,
is for incorporation in the building sprinkler system. For this reason, the
sprinkler contractor will need to review the water requirements and number of
nozzles.

Note: VM duct and plenum nozzles are rated at 325EF. For special
applications or for equipment not shown in this chart, consult the factory.
Nozzles have a 1/4" orifice.
Backshelf ventilator
Duct and plenum protection is required for dry-type hoods only when surface
protection is needed or when local codes and regulations specify it. (See
Figure 48.)

65

Ventilation Systems
Fryers

Positioning of the nozzle must be within a 6” area of the nozzle plane,
as shown in Figure 49, with the center of the plane 3” back from the
center point of the fryer. The mounting height of the nozzle is 24” min.
to 42” max. as measured from the fat surface to the nozzle deflector.

Ranges, griddles, hot tops and hot plates
For any of these types of equipment or combination of them one nozzle will
cover up to 6 ft of equipment length. The nozzle mounting dimensions are as
shown in Figure 50. The head temperatures are summarized in Table 11.

Ranges, griddles, hot tops and plates with high shelves
The rules for positioning a nozzle above the ranges, griddles, hot tops and plates
apply when those types of cooking equipment are equipped with high shelves.
The only difference is that the nozzle must be within the 6” square area starting
1” in front of the high shelf and centered left to right
over the equipment. Similarly, the mounting height is 24” min. to 42”
66

Installation
max. as measured from the cooking surface to the nozzle deflector (see Figure
51). For the head temperature range, refer to Table 11.

Salamander broiler
Each salamander broiler requires a nozzle. This must be positioned within the
nozzle plane area 1” to 3” below the broiler compartment opening and between
0” to 3” in front of the opening. See Figure 52, which includes the applicable
head temperature information.

67

Ventilation Systems
Upright broiler
One nozzle is required for each compartment of an upright broiler, each nozzle
being positioned in the same place specified for the salamander broiler (see
Figure 53).

Tilt fry pan

A tilt fry pan up to 48” wide requires one nozzle positioned within the nozzle
plane 6” square area, starting 1” in front of the fry pan center and centered
left to right. The head temperature is 175oF.
A fry pan cover in the upright position may require a different
nozzle location. This is best determined by checking the clearance when the
cover is moved from the closed to the open position (see Figure 54).

68

Installation
Conveyor broiler
Conveyor broilers require three nozzles, one for each conveyor opening
positioned within a 6” square area nozzle plane and the third for the exhaust
opening. The plane is 1” to 2” below the bonnet or opening flush with the end
of the bonnet and centered left to right on the end of the broiler (see Figure 55).
Plenum protection for hoods
One nozzle protects up to 10 ft. of plenum length, the nozzle to be positioned
in the center of the plenum, left to right, and 2 1/2” away from the back of the
plenum. Two nozzles are required for a plenum of between 10 ft. and 20 ft in
length. The nozzles are to be positioned 1/4 of the total length from each end of
the plenum and 2 1/2” from the back of the plenum. See the threeviews shown
in Figure 56.
1" pipe

1" pipe

Duct collar
1" pipe

Max. 10' 0"

A'

2xA
10' 0" to 20' 0"

Front elevation

Front elevation
2 1/2" +/- 1/2"
1 1/2" to 2 1/2"

Top of pipe
Make sure top of
pipe clears swing
of damper

Section at pod

69

Figure 56 - Plenum protection

A'

Ventilation Systems
Duct protection for hoods
Duct protection is required only when it is specified or required by local
codes.
One nozzle will protect a duct with a maximum dimension of any side
not exceeding 30”. The nozzle should be positioned in the center of the duct
within 1” min. to 12” max. from the top of the damper blade.
Ducts 31” and larger on any side require two nozzles positioned at
quarter points from sides not equipped with a damper and from the top of the
plenum. Ducts fitted with nozzles require service access doors of adequate
size, grease and water tight, and of approved construction (see Figure 57).
Test valve arrangement
Each suppressor control cabinet requires one test nozzle positioned at the most
remote ventilator after the last sprinkler head of the system. In Figure 58, the
water-wash hood is shown in solid lines, the filter hood arrangement in broken
lines.
Fire system certification
The sprinkler contractor or an agent of the local fire authority is responsible for
certifying the fire system. A manufacturer is not responsible for testing or
certifying the system. Most codes require that fire systems be tested and
recertified annually. A manufacturer is not liable for problems attributable to
water pressure, installation, testing or certification.
Listed grease extractors, electrical controls
The Fire Protection Equipment section deals with specified requirements of
control systems concerning the control circuit to simultaneously energize wash
function of listed grease extractors with the fire protection system. Figure 59
and Figure 60 outline typical wiring interlocks with exhaust hood water wash
panels and cooking equipment shutdown interlocks.

70

Installation

71

Ventilation Systems

72

Installation

73

Ventilation Systems

74

Maintenance

Maintenance

Cyclo-wash and Cyclo-Maze wash
As with any grease extraction unit, it is important to clean and maintain the
equipment because accumulated grease poses a serious fire risk.
If a ventilator hood is not properly maintained, accumu- lated grease
becomes a serious fire hazard.
Automatic cleaning
Grease accumulates in the extractor unit during operation, so the cleaning of the
interior surfaces is part of the cleaning cycle.
When the STOP push button on the Cyclo Wash unit is operated, the
exhaust fan and cold water solenoid are switched off, a pre-set timer energizes
the hot water solenoid and detergent pump system for a short cleaning cycle.
The hot water and detergent mixture is sprayed through a series of nozzles to
scour the interior of the unit.
Daily
C Clean the exterior of the ventilator.
Weekly
C Check the water nozzles to make sure they are working properly.
C Check the detergent container (inside the control panel) and keep it topped up with
detergent. (See the control panel manual for the correct use of detergent.) Note:
VM control panels have a low level detergent alarm.

75

Ventilation Systems
Monthly
C Clean the water line strainers: on both hot and cold water models, if water nozzles
become clogged with scale, remove and immerse them in vinegar for half an hour.
C Check that the solenoids and relay click when the START and STOP pushbuttons
are energized.
C Pour a pint of full strength detergent in the bottom of each ventilator section and
let it sit overnight.
C Check the duct work.
Twice a year
C Thoroughly clean the unit and related duct work to remove grease. A commercial
cleaning service is recommended for this work. The frequency of cleaning will
depend on the type of operation being used.
Non-water wash hoods
Daily/weekly as required
C Use hot water and detergent to clean the ventilator and remove any surface grease.
C Remove and clean the access panels to inspect and clean the interior of the unit.
C Clean the grease collection pans.
Twice a year
C Thoroughly clean the unit and related duct work to remove grease. A commercial
cleaning service is recommended for this work. The frequency of cleaning will
depend on the type of operation being used
General requirements for start-up
C To help maintain the equipment warranty, obtain an authorization number from the
Service Department before starting up the equipment following installation.
C To make sure the service technician is on site at the right time, contact the job site
manager and the dealer for coordination.
C Have the correct drawings available for the equipment start-up.
C The system cannot be fully checked if the kitchen is already in operation. If this
is the case, contact the Service Department for instructions.
C Thoroughly check the system, the ventilators, ducts, air passages, water strainers
and control panel for foreign material: dirt, tape, fabric, tools.

76

Maintenance
Control panel
1.

The control panel is wired with 18-gauge wire and has a 3AG 8
amp fuse. The incoming power line is a field connection at
terminals 1 & 2. Check that there is 120V AC between terminals 1
& 2.

2.

For all field connections to terminals and interlock functions always
refer to the project's shop drawings and control wiring diagrams.

3.

Control panels are for cold water mist and hot wash as well as for
hot water only.

4.

Usually, the water wash control panel governs operation of the
exhaust fan to make sure the fan stops during the wash cycle. Some
units, however, may be controlled by a remote control station or
building management system.

5.

The detergent line (plastic tubing in the panel) should be connected
to the main hot water feed to the hoods. This should be on the
secondary side of the panel and the vacuum breaker.

6.

Check that the cold water pressure at the panel is at 20 psi. of the air
column.

7.

The recommended hot water pressure is 30 psi. At pressures above
40 psi, safety requires the system be fitted with a pressure regulator
if one was not ordered with the unit.

8.

The recommended hot water temperature is in the range 140oF and
180oF. Operating the unit below this recommended range means
that the system will not properly clear out grease; above the upper
limit of the range, grease may be baked on to metal surfaces.

9.

Cold water mist in the hood [distributed from the lower row of
nozzles] greatly improves grease removal.

10.

The RUN switch and the momentary switch will open the cold
water solenoid, and start the fan and mist.
When the switch is in the wash position, the momentary switch
drops out the cold water solenoid and stops the fan. The hot water
and detergent pump are activated.

11.

77

Ventilation Systems
12.

The wash cycle is adjustable from 0 to 10 minutes (2 minutes for
cold water mist models and up to 10 minutes for hot water wash
only models).

13.

The detergent pump has a LOW DETERGENT pressure switch
which, if there is no cleaner in the container, causes a buzzer to
sound. The pump stops almost immediately. If, however, detergent
is flowing through the line and the buzzer is still sounding, it may
be necessary to adjust the setting of the adjustment screw under the
switch cover.

14.

Tighten the detergent line fittings by hand only. Over-tightening can
cause leaks.

15.

It is a good idea to insulate all cold water pipes to help avoid
condensation build up and dripping in warm, humid kitchen spaces.

78

Design

Design

Anyone who works on the design and selection of equipment in commercial
kitchen operations needs a general knowledge of the principles involved. The
purpose of this section is to discuss the factors that affect ventilation system
design. The section includes these subsections:
C

Types of filtration technologies

C

Types of installations and available options

C

Assessing space and operating factors

C

Factors that govern choice

C

The development and use of space

C

Energy management, efficiency and costs

Types of filtration technologies
The majority of kitchen ventilation systems - the 1995 ASHRAE Handbook on
heating, ventilation and air-conditioning applications puts this at 90 per cent
-depend on the grease removal device in the hood for effluent control. For the
most part, effluent controls are mounted on the roof of food service facilities.
Currently, common practice is to carry the effluent from the hoods through the
ducts and then to treat the effluent components. NFPA 96 specifies minimum
velocities in ducts to minimize grease build-up. The trend, however, is to
develop effective effluent control immediately following the hood to reduce the
fire hazard by limiting the spread of the grease contaminant. This can reduce
duct cleaning costs, especially in multi-story buildings and in multiple-hood
systems. Additionally, it could reduce strict construction requirements for fans
and ductwork once the fire safety of the components has been proven. The 1995
ASHRAE Handbook strongly advises designers to pay special attention to
effluent control equipment that traps grease in the removal device.
Full effluent control requires the control of grease in its solid, liquid
79

Ventilation Systems
and vapor state, other solids, and volatile organic compounds (cooking odors).
Failure to remove the grease first will result in the fouling of the odor control
system.
Grease removal starts in the hood with the grease removal devices such as
baffle filters. The more effective these are, the less necessary it is to install
additional equipment downstream of the hood. The next device is almost always
another grease removal device to capture the remaining grease. The odor
removal device follows.
Grease extraction filters are tested and listed for their ability to limit, but
not totally prevent, flame penetration into the hood plenum and duct, not for
their ability to extract grease. Research shows that grease particles are so small
(less than 20 µm diameter) that they are aerodynamic and not easily removed
by the centrifugal impingement principle usually used in grease extraction
devices.
The following summarizes the filtration technologies available today and
applied to varying degrees for control of cooking effluent. Quoted from the
earlier referenced 1995 ASHRAE Handbook, they are listed in common order
of use with particulate control upstream of the VOC
compounds) controls.

(volatile organic

Water mist, waterfall, and water bath: The water forms a barrier that
mechanically entraps the particulates as the effluent stream passes by.
C
Bath types have a high static pressure loss.
C
Spray nozzles need attention to deal with the build-up of scale.
Watermay need to be softened to minimize clogging.
C
Drains can become blocked if the system is not maintained.
Electrostatic precipitators (ESPs): Particulate removal is by high-voltage
ionization, then by collection on flat plates.
C

In a greasy environment, collected grease can build up on the plates in
the precipitator. As the build-up increases and the cell gets dirtier, the
efficiency drops because the build-up reduces the spacing between the
collection plates and drops the resistance, causing arcing and reducing
efficiency.

C

Cleaning is difficult and expensive.
80

Design
Pleated or bag filters of natural and synthetic fibers: Very fine particulate
removal is by mechanical filtration. Some types have an activated carbon face
coating for odor control.
C
C
C

These filters become blocked if too much grease enters.
Static loss builds with extraction, and airflow drops.
Almost all filters are disposable.

Active carbon filters: VOC control is through adsorption by fine activated
charcoal particles.
C
C
C
C
C

Require a large volume and thick bed to be effective.
Heavy and can be difficult to clean and replace..
Expensive to change and recharge. Many now are disposable.
Quickly ruined if they become grease coated or subjected to water.
Some concern about increased fuel hazard in fire.

Oxidizing pellet bed filters: VOC and odor control is by oxidation of gaseous
effluent into solid compounds.
C
C
C
C

Require a large volume and long bed to be effective.
Heavy to handle and can be difficult to clean.
Expensive to change.
Increased oxygen available in a fire is of some concern.

Incineration: Particulate, VOC, and odor control is by high-temperature
oxidation (burning) into solid com- pounds.
C
C
C
C

Must be at system terminus and clear of combustibles.
Expensive to install with adequate clearances.
Can be difficult to access for service.
Expensive to operate.

Catalytic conversion: A catalytic or assisting material, when exposed to
relatively high-temperature air, provides additional temperature that is adequate
to decompose (oxidize) most particulates and VOCs.
C
C

Requires high temperatures (260oC minimum).
Expensive to operate because of high temperature requirement.

In addition, for fire safety, grease should be eliminated entirely or drained from
the duct to a safe container.
Liquid odor control systems: Dispense a powerful odor eradicator into the
81

Ventilation Systems
cooking exhaust air on a continuous programmed cycle. This mist spray of
atomized particles permeates the exhaust air, attacks and neutralizes airborne
odors and the bacteria that cause odors. The odor control system works
continuously while the exhaust fan is operating.
C
C

Requires regular replacement of solution.
Will work with organic odor molecules only.

Exhaust system terminations
Rooftop terminations are preferred because the discharge can be directed away
from the building, the fan is at the end of the system and is accessible. The
common concerns with rooftop terminations are:
C

The discharge of the exhaust system should be arranged to minimize
re-entry of effluent into any fresh air intake or other opening to any
building. This requires not only a separation of the exhaust from
intakes, but also knowledge of the direction of the prevailing winds.
Some codes specify a minimum distance to air intakes.

C

If a fire occurs, neither the flames, nor the radiant heat, nor the dripping
grease should be able to ignite the roof or nearby structures.

C

All grease from the fan or the duct termination should be collected and
drained to a remote closed container to preclude ignition.

C

Rain water should be kept out of the exhaust system and especially the
grease container. If this is not possible, then the grease container should
have a design that separates the water and grease and drains the water
back onto the roof. Figure 63 shows a roofing upblast utility set with
a stackhead fitting, which directs the exhaust away from the roof and
minimizes rain penetration. Discharge caps should not be used because
they direct the exhaust back toward the roof and can become fouled with
grease.

Outside wall: The fan of a wall termination may or may not be the terminus of
the system, located on the outside of the wall. The common concerns with wall
terminations are:
C

Discharge from the exhaust system should not be able to enter any fresh

C

air intake or other opening to any building.
Adequate clearance from combustibles must be maintained.
82

Design
Upper stack held off from
lower stack 10 mm ON ALL
SIDES. Bracket upper
stack to lower stack.
4 Dh

150 mm min.
For round duct, Dh = D.
For rectangular duct,
Dh = (H + W/2)
Reducer if necessary to
increase stack velocity
to disperse effluent

C

C
C
C

Duct sections should pitch back to the hood inside, or a grease drain should
be provided to drain the grease back into a safe container inside the
building to prevent grease from draining down the side of the building.
The discharge must not be directed downward or toward any pedestrian
areas.
Louvers should be designed to minimize grease extraction effects and to
prevent staining the building facade.
To ensure clean, safe exhaust discharge, an approved air filtration device
should be added in the duct system.

Upblast utility set
Source: 1995 ASHRAE
Applications Handbook (SI)

Figure 63

Types of installations
In the introductory chapter to this manual we touched on the types of buildings
in which commercial kitchen operations are conducted. These include high-rise
buildings of various architectural designs, some suited for venting to the roof
and some not. Historical sites, food courts, existing buildings such as hospitals,
schools and penitentiaries all present the designer with features and factors not
found elsewhere.
Although each site requires separate assessment, study and treatment the
following illustrates some of the problems encountered and factors to take into
account.
In general, considering both traditional and non- traditional sites, a number
of options are available to the designer. Options 1, 2 and 3 following illustrate
three of these.
An existing installation
Roof-mounted exhaust and make-up air systems are installed to meet the
applicable codes. The design shown in Figure 64 exhausts 100 per cent of the
required air volume and replaces 80 per cent of the make-up air directly back
into the kitchen using outdoor air through some type of ventilation unit, which
possibly provides heat, air conditioning and free cooling.

83

Ventilation Systems

E/A Exhaust air 100%
HVAC unit






The exhaust system serves several functions.
Exhaust fan
The system removes grease-laden vapors as
Local and NFPA
per the codes.
Code requirements
It also removes kitchen cooking, preparation
and serving odors.
It provides general ventilation and air change
required in all kitchens.
Exhaust hood
Maximum 80%
Keeps the kitchen under a negative pressure to
Odors make-up air
contain all odors within the space.
Grease, odors & heat

Cooking

Serving

80% fresh air

20%
transfer

Preparations

Figure 64 - An existing installation
Option #1 If there is adequate general ventilation available from the HVAC system for that space, a re-cir
culation, exhaust air cleaning unit for the kitchen operation may be the answer, as shown inFigure 65.
.

Adequate general ventilation from the building
system for the space should:

remove heat and odors from the cooking
Preparation and serving areas of the kitchen;

provide the required air changes; and
prevent kitchen odors from being carried to

building areas beyond the kitchen space.

Exhaust air of
general building
system

Fresh air inlet of
general building
system

Inlet air
Clean, recirculated
air

Cooking

Return air

Serving Preparations

Figure 65 - Exhaust air cleaning unit
Option #2 If there is no existing exhaust-ventilation system in the building or it is not available for kitchen

operations, cleaned exhaust air can be vented through an exterior wall for low level exhaust asFigure 66
illustrates.

Transfer air from surrounding areas can be
used to provide the required air changes.

Clean exhaust air
Low level exhaust

Cooking operations using a
VM recycle hood, which
has capacity and power to
add ductwork for serving
and preparation operations

Transfer air

Cooking

Serving

Preparations

Figure 66 - Exterior wall ventilation

84

Design

A VM recycle hood system returns 70% to 80%
of the air directly back into the existing system

Option #3 If the only available exhaust is through exist

ing ductwork with low volume capacity, then the recycle
option may be able to be used on the air cleaning unit.
Containment of odors and the build up of heat needs to
be considered with care.

Existing ductwork for other systems
Making use of a VM recycle
30% to 50%
hood with a direct recirculation
clean exhaust option
air
30% to 50% transfer
air or outdoor air

Cooking Serving Preparations

Figure 67 - Recycled ventilation

Options using clean air filtered systems
Option #4 Using an approved air cleaning system,
operators can now exhaust out of the side of a building
and owners will no longer be required to provide vertical
fire-rated shafts and duct runs to 40 in. above the roof.
Figure 68 shows a clean, low level exhaust arrangement
in a single-story building.

Filter
Clean exhaust air
Low level exhaust
Fan

Odors

Cooking

Transfer
air

Serving Preparations

Figure 68 - Clean, low level exhaust

Fan

Option #5 The use of the low level exhaust arrangement
shown here means a wall exit can be used in a
multi-story building such as a tower block.

Odor
Filter

Figure 69 - Side wall exit in multi-story building

85

Ventilation Systems

Odor control
Factors that affect cooking exhaust odors are:
1 Food being cooked. Fish, chicken, sauces and marinades, garlic, etc.,
produce noticeable cooking odors.
2 How food is cooked. Broiling, frying, wok and sauté produce smoke, steam
and vapors that carry odors. High heat, charring or burning may increase
odor production.
86

Design
3 The number of meals cooked per day and actual cooking hours.
4 The volume of air in CFM exhausted from the kitchen.
5 The state of cleanliness of the ducts, hoods, cooking equipment and the
presence of rancid grease and garbage odors.
Liquid odor solution
The use of non-approved products in Ecoloair and Ecolo-spray odor-reducing
units voids the warranty on odor control and other components that may be
affected, including the fan and motor. The liquid solution works. It does not
clog the nozzle nor does it leave oil or harmful residue downstream of the odor
cabinet.
Special odor problems
The sense of smell is subjective. What one person finds pleasant another might
find unpleasant. When cooking odors collect in confined areas of buildings, in
cul-de-sac areas, courtyards and similar places one's sense of smell is
heightened. Otherwise pleasant cooking odors become offensive and present a
problem. This may have nothing to do with how good or bad the odor is as
much as the fact that the smell is inappropriate because it is ”retail space” or
”office” or ”residential territory”. The restaurant operator may wish to select
”continuous spray” settings on the odor control equipment as the preferred
option to handle tenant complaints or, even worse, health department citations
and law suits. In these circumstances, the use of filtration and odor-reducing
equipment may make the difference between being permitted to operate a
restaurant or not. In such cases, cost is of secondary importance.
Elements of ventilation design
Many factors affect the choice of a ventilation system that is right for a given
operation. Some are obvious from the options discussed for new and
non-traditional site problems encountered. One of the most important, however,
is cost. When cost is examined in terms of capital outlay and operating costs,
the whole concept of life cycle costing can be assessed in its proper perspective.
That is, a choice between high and low capital cost must be analyzed in
87

Ventilation Systems
relation to the life cycle cost to have meaning in terms of the whole economic
investment. For example, the cost of a conventional hood as compared with
an engineered ventilation system (EVS) pales into insignificance when the
initial savings are quickly lost in increased operating expenses. The same
reasoning can hold true for other major items of a system: the ducting,
extraction fans, grease extraction and controls.
Use of the available space for designing and installing an economic kitchen
ventilation system to manage the by-products of a cooking operation also
centers on basic elements. These are factors that affect the containment of
odors, equipment sizing and, by extension, the overall efficiency of the
operation. The elements are:
C
C
C
C

The cooking equipment to be used
The type of kitchen operation planned
The ventilation and make-up air required
Compliance with the regulations

Where does assessment begin?
Assessment begins with a thorough understanding of the facts, conditions and
circumstances of the particular case. A disciplined approach to research and
intelligent use of the results is the surest way of containing costs by making the
most economical decisions. It is recommended that kitchen designers and
consultants follow these recommendations.
First
Note and record all the operating parameters and limitations of the proposed or
available space. This applies to new and proposed, as well as existing, space
intended for conversion from some other function into a cooking operation.
What is the condition of the existing HVAC system? What structural
limitations are there for running ducts? What are the wall enclosure designs for
the cooking banks? What false ceiling space is available? These are the types
of questions to ask and answer.
Second
Based on the type of cooking operation planned and the type and configuration
of cooking equipment to be used, calculate the exhaust air required; (see Air
Flow Section for the formula to calculate the exhaust air).
88

Design
Third
Calculate the make-up air required. This is where knowledge of the installed
HVAC system on an existing site is important. It is necessary to know the
volume of air delivered to the kitchen area by the HVAC system to calculate the
make-up air needed to offset the air exhausted from the kitchen.
Fourth
The NFPA 96 Standard is an excellent source of reference for making sure the
ventilation equipment complies with national requirements.
All the factors so far discussed can and do present problems in applying
ventilation principles. Frequently, problems stem from inadequate assessment
of the proposed cooking operation and the majority arise from ignoring factors
that affect the ventilation equation in some way. Conditions vary from site to
site, so it is necessary to assess everything that can change them.
Fifth
Odors are contained in the kitchen area by keeping the atmosphere under
negative pressure and then removing them through an exhaust hood using a
ventilation system of adequate capacity.
In energy management, it is necessary to calculate the minimum exhaust
required to permit efficient operation at the least cost. Energy costs money. The
less energy used to exhaust cooking vapors and provide make-up air, the lower
the operating cost. Efficient ventilation reduces operating costs and extends the
equipment's operating life. If, however, there is not enough exhaust air then the
kitchen space cannot operate efficiently and the cooking equipment will not
perform properly.
Sixth
Many problems occur in renovations or the conversion of space to a kitchen
operation through insufficient attention to detail.
In a traditional site application a separate, kitchen roof-mounted exhaust
and make-up air system is fairly common. The design shown in Figure 64
exhausts 100 per cent of the required air volume for cooking exhaust and
replaces 80 per cent of the make-up air directly back into the kitchen, using
outdoor air. This is done through some type of ventilation unit that may provide
heat and cooling.
An installation of this kind does all the things a good design requires:
89

Ventilation Systems

C

It removes grease vapor, heat and odors produced from the cooking
areas of the kitchen.

C

It exhausts heat from other kitchen heat sources, including compressors,
toasters, lighting and hot food containers.

C

It provides general ventilation and the required air changes specified by
health codes.

C

It maintains the kitchen under negative pressure, to confine cooking
odors to the kitchen space.

The lay-out of cooking equipment is another important consideration in the
choice of the ventilation system. Equipment installed in an ”island pattern” in
the central space of a kitchen has different air flow characteristics from ovens,
broilers and deep-fry units installed alongside a wall or other enclosed
arrangement. The designer must take the position of the cooking equipment into
account and note all wall enclosures for exhaust air volume requirements.
Options
Within the boundaries of physical limitations and regulatory control, there is a
range of options in the choice of a ventilation system. Choice depends on the
shape and space of the kitchen area, the cooking equipment selected, restrictions
imposed by various authorities, and the in-built HVAC system.
We discuss the shape and limitations of various structures as governing
factors of choice in the next section. Even so, in most instances the choice of
a ventilation system ranges from the simple exhaust of cooking vapors to a
self-contained recirculating system requiring minimum make-up air. In all
instances fire protection is of prime importance.

90

Design
Efficiency and costs
The life cycle cost of any electro-mechanical equipment has two main
components: the capital cost of the installation and its maintenance and
operating cost. Owners are concerned with the capital cost of the ventilation
system; the operator, however, in addition to paying for the installation, must
also consider the cost of upkeep and maintenance. Large chains that own and
operate commercial cooking operations concern themselves with the life cycle
cost of the installation.
Designers need to choose equipment based on a knowledgeable
understanding of the life cycle equation; will the client opt for a top-of-the-line
installation for the highest efficiency or be reconciled to something less? This
and similar questions are important and require answering. This is where
ventilation experts can help.
The efficiency of the system, its capital cost, and estimated operating cost
are important factors to consider when choosing equipment.
Factors that govern choice
Discussing the need for kitchen ventilation, we have dealt with the main
principles that affect ventilation. More particularly, what factors govern the
choice of a system? There are four main categories: structure and ecology; type
of cooking equipment; kitchen lay-out and equipment placement; and the type
of heating source used (gas, electricity or steam).
Placement of equipment
The placement of cooking equipment in the kitchen area dictates the type of
ventilation hood required to capture and contain the exhaust stream. The
combination of hood and equipment placement also influences the type and
capacity of the HVAC (heating, ventilation and air-conditioning) system.
Is the kitchen equipment in an island configuration? Is it placed against a
wall? In a corner? How does placement affect cfm calculations for ventilating
the space?

91

Ventilation Systems

Sound levels
The subject of equipment noise was discussed in the Installation Section, under
the subheading Sound Levels. It is worth repeating here. Noise is an especially
important consideration of ventilation systems about which kitchen designers
should be aware. Sources of noise in ventilation systems include:
C

Inadequately-sized air inlet and exhaust ducting for type and size of fan
or fans installed.

C

Poorly anchored duct runs that produce resonant vibrations in the
system.

C

Air leaks in ducting from poor mechanical joints.

Equipment specifications increasingly include limitations with regard to noise
levels as measured by a decibel meter against some standard.
Heat source
The source of heat used for cooking is relevant to the ventilation system. Gas
produces carbon dioxide, which may need additional exhaust capacity.
Electricity is comparatively expensive and steam needs humidity control.
Typical full-scale Restaurant Schematic
Figure 71 and Figure 72 shown overleaf are of a typical restaurant schematic
to illustrate possible design problems the designer needs to consider.
Figure 71 shows the physical lay-out of a drive-through restaurant, its
seating plan, entrances, exits, and service areas.
Superimposed on this lay-out are the key points to consider, as shown in
Figure 72. These include possible odor problems, the build- up of grease and
acids on the roof top exhaust fans and fresh air intakes of the HVAC equipment.

92

Design

Surrounding
commercial and/or residential area
Street front
Optional outdoor
playground
Entrance

Entrance

Exit

Serving area
General
seating

Drive through
pick up
Kitchen area

Entrance

Delivery and
Washrooms services
Parking varies
Figure 71 - Layout of typical
drive-through restaurant

Figure 72 is the same lay out as shown in the
preceding Figure 71 illustration, but with seven key
points superimposed. These include possible odor
problems, the build-up of grease and acids on the
roof-top exhaust fans and fresh air intakes of the
HVAC equipment. Table 17 summarises the possible
problems by type in the various areas.

1
Surrounding
commercial and residential areas

Playground &
2 pedestrians

Entrance

Exit

Building
3 entrances

Possible problems

Area
1
2
3
4
5
6
7

Smoke
x
x
x
x
x
x
-

Odor
x
x
x
x
x
x
-

4

Grease
x
x
x
x

Building HVAC air
intakes and equipment

5
Roof
7 area

3

Climate and
prevailing winds 6

Table 17

Figure 72 - Smoke, odor, grease design
considerations for outdoor areas

93

Kitchen exhaust
discharge

Ventilation Systems

Exhaust Hood Ventilation Design Checklist
Budget parameters
Type of ventilator required:
[ ] Self-cleaning (water wash)
[ ] Dry slot type
[ ] Conventional baffle filter type
$ per linear ft. __________________
What codes and standards
apply?
[ ] U.L.
[ ] BOCA
[ ] NFPA 96
[ ] NSF
[ ] UL/ULC
[ ] UMC
[ ] SBCC
[ ] AGA/CGA
[ ] Local codes _________
Equipment to be ventilated
[ ] Junior range
[ ] Ranges with open burners
[ ] Single-deck ovens
[ ] Steamers and kettles
[ ] Counter equipment, light duty
[ ] Ranges
[ ] Deep fat fryers
[ ] Multi-deck ovens
[ ] Single-deck broilers
[ ] Multi-deck broilers
[ ] Salamanders
[ ] Heavy duty counter equipment
[ ] Tilting fry kettles
[ ] Solid fuel apppliances
[ ] Salamanders over range
Type of fuel
[ ] Gas
[ ] Electric
[ ] Steam
[ ] Solid fuel (charcoal, mesquite)
Options to be included
[ ] Lights
Type__________
[ ] Manifold and drains
[ ] Utility riser cut outs

[ ] Trim and finished ceiling
Automatic wash down system
If a water wash ventilation system
[ ] Additional hood depth for
with more than a 60ft. hood is planned,
non-standard cooking equipment
Exhaust demand sizing
will the cleaning cycle be:
[ ] Simultaneous operation
CFM requirements vary according to the
[ ] Independent/sequential
lay-out of the cooking equipment. For
operation
instance, if the layout consists of one
heavy piece and several light pieces, one (This determines the number and type
of control panels required.)
may lower the nominal range of CFM
Architectural considerations
used. The general rule for exhaust
[ ] Are there ceiling height problems?
Demand calculations is:
[ ] Are there obstructions, such as
Light
- 250 CFM/linear ft.
beams and colums?
Medium - 300 CFM/linear ft.
[ ] If a wash-type ventilator is
Heavy - 350 CFM/linear ft.
planned, are the floor drains
(See Figure 34 in Airflow Section for
and grease traps suitable
detailed calculations.)
and of adequate capacity?
Low volume ventilation
Depending on the architectural conditions [ ] Do the overhead structural
conditions permit the
and local regulatory authorities, low
proper erection of exhaust
volume ventilation (150, 180, 210
ducting, plumbing, and gas
CFM/linear ft.) may be appropriate. We
lines without interference?
recommend that designers consult VM
[ ] Will the access doors,
engineering staff to see if this cost saving
windows, elevators allow
option is suitable to the application.
entry of the hood when
Type of hood
the construction is completed?
[ ] Wall mount [ ] Island mount
[ ] Is there provision for utility
[ ] Canopy style
raceways?
[ ] Backshelf style
[ ] Are the supporting walls
Make-up air
combustible?
Is the supply air system for the kitchen
(In
some
areas a 3" space is required
exhaust hood to be provided by:
for hood walls. 3" space is standard on
[ ] Room HVAC
VM hoods for wall mounting.)
[ ] Ceiling grills and diffusers
[ ] Tempered (front discharge
method) from the hood
[ ] Untempered supply air
plenums, hood or ceiling mounted
In cold climates make-up air tempered to 55 oF (min) is recommended.

Table 18 - Hood check list

94

Design

Fire Protection Ventilation Design Checklist
Fire protection
[ ] Will the fire protection
system be part of the
ventilator specification?
Check the type of fire protection
system planned:
[ ] Wet chemical (i.e. ANSUL
R- 102)
(Liquid chemical systems are
currently UL listed for charcoal or
solid fuels.)
[ ] Water mist "suppressor"
(If water mist is selected,
is there a sufficient water
supply in the building fire
sprinkler system?)

These points can serve as a
guideline to determine the client's
needs for an effective ventilation
system. As the project designs are
completed, the issues and questions
noted here will supplement the
planning function and ultimately
Note
To make certain that the client's needs result in client satisfaction.
are met, a certified test and air balance
of the ventilation systems can be
included in the project specification.
This work may be incorporated into
the kitchen (Division 11) or mechanical (Division 15) contract.

Type of fuel
[
[
[
[

]
]
]
]

Gas
Electric
Steam
Solid fuel (charcoal,
mesquite)

TM

EcoloAir Checklist
What codes & standards
apply?
[
[
[
[
[
[
[
[
[

]
]
]
]
]
]
]
]
]

U.L.
BOCA
NFPA 96
NSF
UL/ULC
UMC
SBCC
AGA/CGA
Local codes ---------

[ ] Are the required controls
and sensors specified?
Alarms? temperature
controls? Filter pressure
switches?

Optional equipment

[ ] Does the unit include an
ecology reclaim system?
[ ] If so, is the cfm, total static
pressure, power supply, fan
motor HP and BHP specified?
[ ] Is the unit to be rooftop
Capacity & technical data
mounted, floor mounted or
[ ] Delivery in cfm -------suspended above the ceiling?
[ ] Static pressure_-------[ ] Is the exhaust fan data covered? [ ] Is a mixing chamber and
the type of filter specified
[ ] HP of motor
(i.e., a 2", 40% efficiency
[ ] Fan RPM
filter)?
[ ] Power supply voltage
[ ] Is a temperature controller
[ ] Single phase or 3-phase
located in the control panel
[ ] Are the filters and filter
specified?
efficiencies specified?

Table 19 - Fire protection design checklist

95

[ ] Temperature sensor in
the Energy Reclaim
Module?

Note
This is a checklist reminder of the
applicable codes and standards, the
main features needed to meet a
particular client's needs. A detailed
specification for an Ecoloair assembly is provided in the Codes and
Equipment Specifications
Section following.

Ventilation Systems

Exhausting multiple kiosks in food court applications
Food courts using multiple kiosks present designers with a number of
options for exhaust fan arrangements. Following are four possible
arrangements together with the advantages and disadvantages of each.
The comparison chart shown in Figure 73 following shows
typical food court exhaust requirements for a variety of food court
operations. Calculated exhaust requirements for a given food court
operation will depend on the size, type and capacity of the food service
operation. Nevertheless, the chart is a representative sampling of food
service operations.

96

Design
Option A
System diagram and budget pricing
GEF exhaust
fans - ULC
listed

Note:
The installation may require two or more shafts to balance the air flow
if the duct runs are too long or too difficult to size properly.
Budget Pricing:

Exhaust fan 16,000 cfm
Welded duct work and fire-rated enclosures
Indirect gas fired make-up air heater 16,000 cfm
rooftop unit
Installation cost for above equipment
Shaft requirements
Loss of rentable floor space for shafts
NFPA 96 welded
Relocation costs of exhaust fan and shaft extension
& fire-rated
if additional floors are planned for the future
enclosed duct

Kiosk-mounted
exhaust hoods

$?
?
?
?
?
.
?
____
$

Figure 74

Option A
Central fan for all kiosks
Under this option, a single, roof-mounted fan connected to a main exhaust
duct serves each kiosk area via the branch ducts.
Advantages
C
It is the least expensive option.
C
It saves space because a single duct requires less floor and ceiling space
for exhaust shafts and fire-rated enclosures as required by codes.
Disadvantages
C
Difficult to balance exhaust cfm of each kiosk, as balancing dampers are
not per- mitted in ducts.
C
Difficult to change once installed: duct runs sized for originally
designed cfm and ducts welded.
C
If one kiosk shuts down due to fire, the exhaust velocity may fall below
the minimum of 1,500 fpm allowed by code and require a shutdown of
C
C

the entire system.
Local jurisdictions may not permit other kiosks to run when one is shut
through fire.
A kiosk shut down by fire is not protected should fire occur in another
kiosk. On single fan systems, fire protection systems work as one and
shut off all equipment until the fire system is recharged.
97

Ventilation Systems

Option B
System diagram and budget pricing
GEF exhaust
fans - ULC
listed

NFPA 96 welded
& fire-rated
enclosed duct

Kiosk-mounted
exhaust hoods

Future roof line requires relocation
of fan and NFPA shafts

Budget Pricing:
Exhaust fan complete with roof curb
Welded duct work and fire-rated enclosures
Indirect gas fired make-up air heater
16,000 cfm rooftop unit (central)
Installation cost for above equipment
Shaft requirements
Loss of rentable floor space
Future relocation costs for fans if required
Interlocking of exhaust fans

Figure 75

$?
?
?
?
?
?
?
____
?
$

Option B
Separate exhaust for each kiosk
Under this option, each kiosk has a separate exhaust hood and roof-mounted fan.
Advantages
C
C

Easily balanced by adjusting the fan rpm.
Easy to adjust provided ducts are sized to accommodate cfm changes within a

C

fixed range.
As each kiosk operates independently, it does not need to be shut down for fire in

another unit.
Disadvantages
C
C
C
C

Supply and installation of multiple exhaust shafts and fans is expensive, although
its flexibility makes this the most commonly used system.
Fans occupy a large roof area.
Separate systems are too small to justify the cost of a future heat recovery
installation.
The relocation of fans to accommodate changes in equipment lay-out is
98

Design
required.
C
If a central make-up air system is used, exhausts should be interlocked to a timer
system. Alternatively, separate make-up air systems are needed for independent
operation. Independent operation requiring increased roof area is common, but
code exhaust outlets and make-up air inlets must be 10ft. apart.

Option C
System diagram and budget pricing
Roof-mounted ecology
exhaust unit (mount fan
indoors if possible)

Future addition and duct
extension (if required)

Standard duct work
- not NFPA welded

Future addition and
duct extension (if
required)

Standard duct work,
ULC (Canada approved)
U.S. jobs require local
code authority approval
for non-welded ducting
Ecology filter box
(indoor mounted)

Kiosk-mounted
exhaust hoods

NFPA welded and fire
rated enclosed duct
work

Budget Pricing:
VM Ecology B-20 exhaust fan, 20,000 cfm roof mounted
VM Ecology EF-20 filter box, indoor mounted
VM odor control
Duct work - NFPA welded and standard
Indirect gas fired make-up air heater, 20,000 cfm rooftop unit
Installation costs of this equipment
Extra cost to add heat recovery section (optional)
Benefits to add odor control
Savings to add future kiosks without relocating fans
Savings for duct cleaning and roof replacement

Figure 76

$?
?
?
?
?
?
?
?
?
___
?
$?

Option C
Central ecology system
The central ecology system option serves all kiosks in much the same manner
as the common fan of Option A. The difference is the addition of the
99

Ventilation Systems
filter unit, which can be located indoors if need be.
The ULC listed ecology system eliminates grease and smoke from exhaust
air. Odor control is an optional addition. The use of an ecology unit eliminates
the need for roof top discharge of exhaust air as well as welded duct work on
the secondary side of the filter box. (In the U.S.A., check local codes for
approval.)
Advantages
C

The exhaust air and ducts on the secondary side of the filter unit are
clean.

C

Because the exhaust is clean, it can be discharged through a building
side wall and does not have to exit through the roof.

C

The equipment is less expensive than separate filters (see Option D).

C

A single shaft occupies less space than multiple shafts required for
Option B.

C

Standard duct work between the filter box and building exit does not
require welding nor a fire-rated enclosure. (In the U.S.A., check local
codes for approval.)

C

Heat recovery equipment can be added without the wash down feature.

C
C

Increased fire safety can reduce insurance costs.
Odor control is easily added.

C

Reduced expense in installing a single exhaust duct.

C

If a kiosk is added, additional filter boxes can be tied into the existing
system.

C

If a new level is added to the building, the ecology unit need not be
relocated. A duct extension will accomplish the change or be redirected
through a side wall.

C
C

The cleaning of ducts is minimized.
The discharged air is clean and grease free.

Disadvantages
C
C

Increased capital equipment cost.
As with Option A, air balancing is difficult.

100

Design

Option D
System diagram and budget pricing
Roof-mounted ecology
exhaust unit (mount fan
indoors if possible)

Future addition and
duct extension (if
required)

Future
systems

EF-4 ecology
filter boxes

Standard duct work
- not NFPA welded

Kiosk-mounted
exhaust hoods

Standard duct work,
ULC (Canada approved)
U.S. jobs require local
code authority approval
for non-welded ducting
Balancing
dampers
with
filter
systems

NFPA welded
duct work

Budget Pricing:
VM Ecology B-30 exhaust fan (total 8 units x unit price)
VM EF-4 Ecology filter boxes (total 8 units x unit price)
VM odor control mounted on roof
Duct work - NFPA welded and standard
Indirect gas fired make-up air heater Temprite TDM-20,
20,000 cfm rooftop unit
Installation costs of this equipment
Extra cost to add heat recovery section (optional)
Benefits to add odor control
Savings to add future kiosk
Savings for duct cleaning and roof replacement
Benefits to balance system easily

$?
?
?
?
?
?
?
?
?
?
___
?
$?

Figure 77

Option D
Central fan and separate filters
This option consists of a single roof-mounted exhaust unit and a separate
filter unit for each kiosk.
Advantages
C
C

Ducts and the exhaust air are clean.
Standard duct work between the filters and fan need not be welded or
fire rated (as ULC approved in Canada; in the U.S., check local codes).

C

With a 4,000 cfm filter box per kiosk, there is room for future
expansion. (The cost difference between 2,000 cfm and 4,000 cfm
filters is minimal, whereas the doubled capacity accommodates any type
of kiosk size.)

C

A single main exhaust shaft occupying less space than multiple shafts
reduces costs.
101

Ventilation Systems
C

Additional kiosks easily added.

C

Future heat recovery and odor control easily added.

C

Again, improved fire safety can reduce insurance costs.

C

Kiosks are independently operable with fire protection shut down.

Disadvantages
C

Increased capital equipment cost.

It is not possible to recommend one of these options over another. The choice
made will depend on the particular circumstances of each application. Life
cycle cost analysis is an important part of any commercial kitchen plan
regardless of the size of the investment. The importance of cost analysis to the
project, however, increases with the level of the capital investment.
For example, Option C discusses the application of central ecology
systems. Their use may or may not be cost effective in single-story structures,
but have a clear advantage in multi-story structures with, perhaps, cooking
operations being conducted at the ground floor or mid-way up the building. In
this case, the expense of an ecology unit will compare favorably with fire-rated
shafts and ducting through many floors to the rooftop.
Filtration System
Ecoloair is the name VM has given to the modular air filtration system for use
in kitchens in which grease and smoke removal, environmental and odor
considerations are of paramount importance. The system contains three
sections: a filter section, an odor-reducing section, and an exhaust section. An
optional section for the Ecoloair filtration system, however, is an energy
reclaim section.
Handling capacities range from 1,000 cfm to 40,000 cfm, although larger
units are available. An Ecoloair unit is applicable:
C
C

where pollution abatement and odor control are required;
in existing buildings with no exhaust, fire-rated shaft or ducting
installed to enable a side wall discharge (that is, at a minimum of 10 ft
above grade);

C

in newly constructed buildings where considerable savings result
102

Design
if costly fire-rated shaft and duct connections to the roof of the building are
eliminated. The Ecoloair system allows the discharge of cleaned exhaust
through the ventilation shaft or via a side wall;
C

where recycling cleaned exhaust air (maximum 80%) into the kitchen
area or ventilator is desired, thus creating savings in the reduction of the
amount of required conditioned make-up air and related equipment.

C

when recycling cleaned exhaust air (80%) into the kitchen area or
ventilator, check local codes for approval.

Benefits of the Ecoloair system are:
C

There is efficient removal of smoke, grease and odors.

C

The unit's efficiency is 99% ASHRAE (on particulates down to 0.3
microns, 95% DOP).

C

The system can be installed in the mechanical room, on the roof of the
building, or in ceiling space.

C
C
C

Pre-wired panels, alarm disconnects, and controls ready for installation.
The elimination of costly fire-rated ducts and shafts.
Clean air duct work for use downstream of the system. (Check local
codes for approval.)

The modular construction of Ecoloair units allows consultants and ventilation
specialists to custom design a system to specific requirements. These are:
C
C

To eliminate the odor control section when it is not required.
To dispense with the exhaust fan section if an exhaust system already
exists and meets the manufacturer's approval.

C

To hang the filter and odor sections in the ceiling space and install the
fan section in a mechanical room.

C

To connect two or more filter sections into one exhaust fan section.

Control panels coordinate the operation of the ventilator and the Ecoloair
system. Turning the main switch on the Ecoloair control panel to the ON
position activates a separate control circuit in the ventilator wash control panel
or a regular motor starter when a dry ventilator is employed. Turning the wash
control panel switch to the RUN or ON position starts the exhaust fan.
Heated, grease-laden air is pulled through the ventilator and a high
percentage of grease is removed from the air stream through the baffled
103

Ventilation Systems
grease extraction system. The exhaust air is then ducted to the filter section
where it passes through a three-stage series of filters, with a final efficiency
rating of 99% as defined in ASHRAE Standard 52-76.
The air is then drawn through the odor-reducing section and sprayed with
an odor eradicator, then through the exhaust fan section and discharged through
the duct work system.
When the system includes the optional energy reclaim section, the heated,
cleaned exhaust air is mixed with untempered outdoor air through a series of
modulating dampers. A temperature-controlling sensor determines the mix for
the correct temperatures of return air to the kitchen area as make-up air. All the
heat needed to return comfort-controlled air back to the kitchen is reclaimed
from the exhaust air, leaving the customer with no additional fuel cost to heat
the kitchen supply air in winter. No supplementary heat is required, as a
temperature controller dictates the amount of heat desired for reclaim. In
summer, the mixing dampers automatically adjust to discharge all of the
cleaned exhaust air to the outside and bring in the required amount of fresh
outdoor air required for the kitchen.
Make-up air supply in a kitchen is normally based on a volume of 80% of
the exhaust volume. This leaves a negative pressure of 20% in the kitchen area,
containing cooking odors in the kitchen.
All fans, exhaust and supply, are sized to suit air capacity of the system,
including an appropriate allowance for external static pressure. In arriving at the
external static pressure for fan sizing, a dirty filter factor of 0.5 is added. This
will account for an average rating of the pressure increase over the three stages
of filters.
A modulating volume control is an available option in lieu of employing
an average ”dirty” filter factor (see ”Typical Ecoloair Unit Selection”).

104

Codes and Equipment Specifications

Codes and Equipment
Specifications

Applicable codes & standards
A number of national codes and equipment labelling authorities regulate the
kitchen ventilation industry, as well as local jurisdictions. Several regions
require approvals for kitchen ventilation systems. Some authorities (The City
of New York, for example) require ventilators and related equipment to have
a Materials Evaluation (MEA) number. In other jurisdictions, departments of
public health issue requirements and guidelines for the design of kitchen
ventilation systems.
To assure clients that equipment selected, recommended and installed
meets local as well as national codes and standards, designers need to keep
informed of changing jurisdictional requirements. As a service to clients in this
regard, VM publishes its Stainless Report, which includes information on local
requirements. Here is a summary of the national codes and labelling authorities,
and their areas of interest.
VM has published a detailed cross reference chart for the major code
publications regulating kitchen ventilation equipment in its Stainless Report 29.
Copies of the chart are available on request.
Building regulatory provisions
Many codes and standards affect HVAC systems and energy use in the building
industry and, by extension, in kitchen ventilation systems. The following
observations represent a cross section of applicable documents reviewed in
North America.
1. Uniform codes of the International Conference of Building Officials
105

Ventilation Systems
(ICBO) are used as a basis for most codes west of the Mississippi River and
the state of Indiana.
2. National codes of the Building Officials and Code Administrators
International, Inc. (BOCA) are used as a basis for most codes east of the
Mississippi River, north of North Carolina and Tennessee, and in parts of
Oklahoma and Texas.
3. Standard codes of the Southern Building Code Congress International, Inc.
(SBCCI) are used as a basis for most codes east of the Mississippi River,
south of Kentucky and Virginia, and in parts of Texas.
4. State-developed codes apply in Wisconsin, New York, and Michigan.
5. The cities of New York, Chicago, Phoenix and Los Angeles apply their own
codes.
6. NFPA standards referenced in the preceding documents apply, as well as
being adopted directly by many state and local regulatory agencies.
7. Similarly, applicable national product standards referenced in the preceding
documents also apply.
Definition of cooking equipment as ”commercial cooking” in applying these
regulatory codes and standards to commercial cooking ventilation will
determine the need for an exhaust hood and duct system. If none is required,
any by-products of the cooking will become an internal load of the building. If
a hood is required, the code may dictate the minimum exhaust, which will, in
turn, affect the amount of make-up air required or a listed hood assembly and
its exhaust requirements may be used.
The need for exhaust
Three questions are asked:
• Under what conditions are commercial cooking exhaust systems and hoods
required by codes?
• Is there a logical matching of effluent quantity or quality or both to the
required exhaust?
• Can the exhaust be segregated to match different loads, or must the exhaust
be based on the worst case in the cooking facility?
106

Codes and Equipment Specifications

A review of these questions in relation to building codes finds:
1. Building regulatory criteria consistently require hoods and exhaust systems
if smoke and grease-laden vapors are produced by the cooking equipment.
There is no provision for considering the relative hazard based on quantity
of effluent.
2. In the most conservative building regulatory provisions, all equipment
associated with a commercial cooking operation may be served by a hood
and exhaust system.
3. Cooking equipment, food preparation, and other aspects of commercial
cooking operations that do not produce smoke- and grease-laden vapors
are not consistently, uniformly, or appropriately addressed. This is
primarily attributable to the failure to consider relative hazard in terms of
quantity, quality, and diversity of cooking effluent production.
4. In all but two instances, the applicability of hood/exhaust requirements is
uniform across all fuel types.
5. Fixed equipment is fully addressed, while portable equipment is less likely
to be regulated, although the latter can produce effluent needing exhaust.
Regional code requirements
Although VM products meet national standards of quality and performance,
several states and city authorities in the United States specifically require
manufacturers and suppliers to obtain approval for the installation and use of
kitchen ventilation systems. Vent Master has approval of its ventilation
equipment in New York City, Baltimore (Maryland), the State of Michigan,
Denver (City and County), Los Angeles, Nevada and Florida. Following is a
commentary on these special requirements.
New York, NY (BSA)
The City of New York requires ventilators to have an MEA number. The
procedure for receiving a file number requires an application, statement and
explanation of compliance with RS-13 (New York City code), and the
submission of complete technical data on products for which the MEA approval
number is required. The Materials Examiner reviews the information submitted
before the application goes in for acceptance. Products receiving an MEA
107

Ventilation Systems
number are listed and a copy is given to the product manufacturer. New
products installed in the City of New York require stickers bearing the MEA
number and a statement of compliance. Vent Master's MEA number is available
on request.
Baltimore, Maryland
Ventilators installed in Maryland must meet the Maryland Department of
Public Health Requirements for design of kitchen ventilation systems. Some of
its specific requirements are:
1. Capture velocity at the perimeter of the cooking equipment must be 50
fpm.
2. The minimum distance for a canopy above the floor is 6.25 feet.
3. The minimum overhang is 12 inches.
4. Grease filters must be installed in T-bar mullions with spring clips.
This guideline also states air quantity requirements for wall and island hoods:
back shelf ventilators will use 250 cfm per linear foot. They require the total
make-up air to be 90% of exhaust quantity. The authority grants no prior
approvals; this is done on a per job basis. Recently, some areas of Maryland
have begun recognizing UL listed products. In these instances, however, the
jurisdictional authority requires a letter of guarantee to confirm compliance with
COMAR 10.15.03.08.C.
State of Michigan
The State of Michigan requires contractors and suppliers to comply with the
Michigan Food Service Establishment Guidelines for Ventilation Systems. The
Department of Public Health requires that contractors submit plans and
technical data for approval before installing commercial kitchen ventilation
systems. The guidelines for ventilation systems cover materials, installation,
hood overhang, filters, grease extractors, and air exhausts.
The formula to determine the requirement for an air exhaust is Q = V x P x D
where:
• Q is the quantity in cubic feet per minute;
• V is the velocity as derived from a table given in the guidelines;
108

Codes and Equipment Specifications
• P is the perimeter in linear feet of exposed hood (i.e., the hood face, exposed
ends and rear on island hoods); and
• D is the distance in feet between the cooking surface and the face of the
hood.
After all the criteria are met and the ventilators installed, the responsible
contractual authority must use an independent environmental, or air quality, test
laboratory approved by the Department of Health to test the installation. The
responsible contractual authority is usually an architect, although the
responsible party could be the manufacturer, designer, building owner, or the
food service operator. The laboratory must submit the results of the test to the
local health authority and the Michigan Department of Public Health, Food
Service Sanitation Section. Once the Section has approved the application it
will issue a Notice of Acceptance (NOA) for that specific installation.
In addition, ventilators that handle exhaust air at rates under those
specified by the State (even though tested by a nationally recognized laboratory)
must be further tested to the satisfaction of the Department of Public Health
following installation. Further, ventilators that use direct (short cycle) make-up
air are likewise subject to testing after installation, with the local Mechanical
Inspector attending to monitor and certify the test.
Denver (City & County)
Commercial kitchen ventilators in the City and County of Denver, Colorado,
must be approved before installation. They must also have a case number.
Drawings, a technical specifications, explanatory literature, and performance
test data from an approved laboratory must support the submitted application.
The jurisdictional authority assigns a case number to manufacturers, who must
supply plans for each installation to obtain a permit. Ventilation systems
manufacturers must comply with the requirements of NFPA 96 and Denver
Building Code. Vent Master case numbers are M-76-36-B and M-83-94-B.
Los Angeles, California
Ventilators installed in the City of Los Angeles requires a Research Report
Number. The City's Mechanical Testing Laboratory issues a Research Report
Number to ventilator manufacturers when it has tested a unit for general
109

Ventilation Systems
approval. Along with the RR Number, the City issues the manufacturer with a
set of conditions with which they must abide. This includes a requirement for
annual renewal of the manufacturer's products and an explanation of any
product changes made. Vent Master's Research Report Number is RR8115.
Nevada
With the recent revision of the categories of UL710 from ”Grease Extractors”
to ”Listed Exhaust Hoods with Exhaust Dampers”, some local authorities have
adopted a stricter interpretation of the UMC Code where air volumes are
concerned. We advise consultation with the local authorities.
Florida
Most of Florida, with the exception of the :Reedy Creek District”, requires the
exhaust fan to activate or remain active with the supply fan shutting down when
the fire system is activated. If a ventilation system includes a damper, the
system exhaust fan must be shut down when the damper closes.
NFPA 96
The NFPA (National Fire Prevention Association) Standard for Ventilation
Control and Fire Protection of Commercial Cooking Operations is the almost
universally accepted standard for the industry. The actual standard is known as
NFPA 96. Some authorities and inspection departments impose supplementary
standards and conditions on the design and installation of ventilation systems,
so it is necessary to make sure that the design and installation package meets
with local approval. NFPA 96 emphasizes these areas of ventilation equipment:
• Grease tight construction
• Location of hoods in relation to the cooking equipment
• Structural integrity of the hood
• Placement and types of accepted fire prevention equipment
• Duct work design and specifications
• Recirculating hood system requirements
BOCA
The Building Officials and Code Administration (BOCA) publish guidelines
for:
• Hood design
110

Codes and Equipment Specifications
• Grease removal
• Duct systems
• Fire suppression equipment
UMC
The UMC concerns itself with the design, construction and installation of
commercial kitchen ventilation systems. The major points covered by the UMC
include:
• Duct work specifications for prevention of grease accumulation
• Hood clearance from combustible construction
• Types of acceptable grease filters
• Canopy size and location
• Capacities for hoods
• Make-up air standards
• Exhaust air standards
One of the best safeguards and guarantees designers and owners have is the use
of UL- labelled units and equipment. City, county and municipal building
inspectors almost always accept labelled equipment as having passed stringent
UL performance acceptance tests. In the interests of safety and satisfaction,
designers should specify the use of UL-labelled equipment only.
Technical specifications
Government regulations at every level govern the kitchen ventilation system
industry. There are building regulations, health, fire, safety and environmental
controls which must be followed. Building permits, standards of inspection,
electrical and mechanical codes, fire standards such as the National Fire
Protection Association (NFPA 96), worker protection guidelines, and local
inspection requirements must be met.
Within the past few years, increasingly stringent ecological standards have
been applied to kitchen operations. They vary from state to state in the U.S.A.
and province to province in Canada, meaning that kitchen designers must
become familiar with local standards. (The same applies to many aspects of
regulatory controls without, however, changing the overall application and
inspection requirements of national standards such as NFPA 96.)
NFPA 96 now includes the majority of all of the various code
111

Ventilation Systems
requirements found throughout North America. This code may be one of the
most helpful in providing the designer with a good understanding of what is
required for commercial cooking ventilation.
Auxiliary clean air filtration
The use of filters is an essential part of the Ecoloair Filtration System. Without
a filter section the unit would be little more than a forced air exhaust or
recirculation system. As the word implies, a filter removes dust, grease and
airborne particles from the air. Air washers and electrostatic precipitators do
much the same thing with varying degrees of efficiency.
Airborne particles range in size from less than 0.1 microns. Although it is
impossible to design a filter that suits every application, it is possible from
experience and empirical tests to choose one suitable for most kitchen
applications. This is one of the reasons why VM needs to know the type of
application for which an Ecoloair system is required.
Filter ratings
Three characteristics distinguish the various types of filter available. These are
the efficiency, its resistance to air flow, and its cleaning cycle. By `cleaning
cycle' is meant the filter's dust-holding capacity. These characteristics are:
• Filter efficiency is a measure of the filter's ability to remove pollutants from
the air.
• Resistance is the static pressure drop across the filter at a given rate of air
flow.
• Capacity is the amount of dust or pollutant a filter can hold. The capacity is
also a measure of the operating life of the filter before it requires cleaning or,
more likely, replacing.
VM filter specifications following are based on various applications in which
VM air filters are installed. The listing is a guide and no more to the
replacement of filters in various applications. Experience will dictate when a
particular filter requires replacing.

112

Codes and Equipment Specifications

Filter specifications
Although VM specifies that all filters used in Ecoloair systems be rated Class
II (as a minimum), ASHRAE specifies these types of filters:
1. Pre-filter: Class II UL; 40% ASHRAE. Non-flammable board or metal
frame. Media - non-woven, reinforced cotton and synthetic fabric, 0.15”
thick with 96% open-area grid. Capacity - 2000 cfm @ 24 x 24 or 1000
cfm @ 12 x 24 at 500 fpm, 0.1” initial static pressure; 0.75 final static
pressure.
2. Bag filter: Class II UL; 90-95% ASHRAE. Galvanized steel retainer and
header; media - spun glass, fire-retardant sealer. Capacity - 2000 cfm @
24 x 24 or 1000 cfm @ 12 x 24 at 500 fpm; 0.7” initial static pressure;
1.25” final static pressure.
3. HEPA filter: Class I UL; 95% DOP; 99% average ASHRAE. Separators;
16 ga. galvanized casing; neoprene gasket downstream; Media - glass,
urethane sealer, fire resistant rating; Capacity - 2000 cfm @ 24 x 24 or
1000 cfm @ 12 x 24 at 500 cfm. 1.0” initial static pressure; 2.0” final
static pressure.
The Ecoloair filter chart shown in Table 20 gives the pre-filter, bag filter and
HEPA filter distribution for the unit sizes shown. VM is approved for filters of
all manufacturers meeting the above filter specifications.

113

Ventilation Systems

Odor control
The liquid deodorizer used in the Ecoloair Filtration System is a blend of many
ingredients. Because the dispensing system is non-aerosol, the deodorizer is
non-toxic and completely free of CFCs. For this reason, the solution is
environmentally and ozone safe, and non-hazardous when inhaled.
Ecoloair/Ecology filter replacement guide
This filter replacement guide is compiled from some projects in which VM has
been involved. Depending on the conditions prevailing at a particular site, it
may be necessary to increase or decrease the frequency for filter changes. In
short, this is a guide, not a specification.

114

Codes and Equipment Specifications

Equipment specifications
The specifications following will interest architects, engineers and kitchen
consultants who need a check list of options. They are also a reliable source of
reference in the compilation of contract bid packages for kitchen construction
and renovation projects. They are based on specified VM products with options
for various combinations of electrical and mechanical services. To prepare a
specification that meets the client's needs, check the appropriate boxes of the
required equipment. These specifications have provision for item numbering
for inclusion in larger specification packages.

115

Ventilation Systems

Filter Hoods
This generic specification is based on VM's Cyclovent range of canopy style ventilators, suitable for all types
of cooking equipment. All Cyclovent ventilators are of the canopy style and the common alpha designation
in the GFIII series of UL/ULC listed filters is GLD for hoods with a damper assembly and GL for hoods
without a damper assembly. Refer to the explanatory listing of models in the Cyclovent range.
Model
-B

Description
Box style hood for ceiling or wall and ceiling mounting (full designation therefore GLD-B for a unit
with damper assembly and GL-B for a unit with out a damper assembly).

-D
-T
-MA

Double sided, island style hood c/w “V” filter section.
Box style hood with tapered sides for ceiling or wall and ceiling mounting.
Hood with integral, front discharge make-up air, c/w 60% perforated s/s panels, air diffuser plate,
make-up air collar.

-DMA

Hood with integral, internal make-up air c/w insulated plenum, interior access door to fire dampers,
air diffuser plate, and adjustable supply air slot.
Low profile style ventilator, wall or equipment mounted for counter top cooking equipment.

-L
ITEM #

The kitchen exhaust ventilator shall be a Vent Master Model:
[ ] Model GLD-__________canopy style ventilator UL/ULC listed with damper assembly
[ ] Model GL- __________canopy style ventilator UL/ULC listed without damper assembly
[ ]

Provide a ventilator constructed of stainless steel with all welded exhaust duct collar with a 1” (25 mm)
connection flange; all joints and seams welded and/or liquid tight; all exposed welds ground and
polished to the original finish of the metal. Provide hanging brackets on each unit for mounting as
required by the model designated.

[ ]

Provide each ventilator with a UL/ULC listed self-closing, spring loaded fire damper assembly activated
by a listed fusible link rated at 286oF (141oC).

[ ] Provide a UL/ULC listed exhaust air volume control damper for optimum balancing of single and
multiple ventilator systems accessible through the ventilator plenum c/w fire damper assembly.
[ ]

Supply all stainless steel UL/ULC listed filters deburred and reversible with grease drain holes top and
bottom.

[ ] Hood size: Length ________ width _______ height _______

116

Codes and Equipment Specifications

Services
[ ] Exhaust air ______________
[ ] Static pressure ___________
[ ] Collar size ______________
[ ] Supply air ______________
[ ] Static pressure ___________
[ ] Collar size ______________
[ ] Electrical: 120/1/60_______ watt
[ ] Direct connect to _______ junction box for lights (by electrical contractor)
Modifications and options
[ ] Lights - the ventilator shall contain - quantity _______
[ ] Flush mount fluorescent light fixtures 36” (914 mm) or 48” (1219 mm) long (2 x 40 watts).
[ ] Flush mount vapor proof incandescent light fixture (2 x 75 watts).
[ ]

Surface mount globe-type light fixtures complete with clear thermal shock proof glass with plated steel
wire guard (1 x 100 watts).

[ ] Offset collar - (specify left or right of center line) duct collars __________
[ ] Rear duct collar take-off.
[ ]

Taper - (on T models) specify taper required __________ to suit low ceiling. Standard is 12”(305 mm).

[ ] Make-up air grilles - double deflection grilles with opposed blade balancing dampers in lieu of
perforated panels.
[ ] Stainless steel main back - where exposed, for island applications.

117

Ventilation Systems

Water Wash Hoods
VM Cyclo Maze wash ventilators are of many types and styles. The designation C-CM, meaning cold water
mist and hot water wash Cyclo Maze, or H-CM, meaning hot water wash only Cyclo Maze, is common to all
models available. Additional alpha designations cover a variety of applications as here explained.
Model
-B
-T
-MA
-DMA
-L
L-MA

-D
-D-MA
-D-DMA

Description
Box type canopy style ventilator for ceiling or wall and ceiling mounting.
Canopy style hood with tapered sides for low ceiling or wall and ceiling mouting.
Hood with integral, front discharge make-up air, c/w 60% perf s/s panels, air diffuser plate.
Hood with integral, internal make-up air c/w insulated plenum, interior access door to fire
dampers, air diffuser plate, and UL/ULC collar.
Low profile style ventilator for wall or equipment mouting for counter top type cooking
equipment.
Low profile style hood, for wall or equipment mounting with integral, front discharge make-up
air for counter top type cooking equipment c/w 60% perf. s/s panels, air diffuser plate, and
UL/ULC collar.
Canopy style, double sided island ventilator for ceiling mouting.
Canopy style for ceiling mounting with front discharge make-up air c/w 60% perf. s/s panels, air
diffuser plate, and adjustable supply air slot.
Canopy style hood for ceiling mounting with integral internal make-up air c/w insulated plenum,
interior access door to fire dampers, air diffuser plate, and adjustable supply air slot.

ITEM #
The kitchen exhaust ventilator shall be a Vent Master:
[ ] Model C-CM__________ hot water wash and cold water mist, UL/ULC listed grease extractor (add
designated abbreviation as required; e.g., C-CM-D-DMA for a canopy style, double sided ventilator for
ceiling mounting with integral internal make-up air).
[ ] Model H-CM__________ hot water wash, UL/ULC listed grease extractor.
Construction
[ ]

Provide a ventilator constructed of stainless steel with an all-welded stainless steel duct collar with a 1”
(25 mm) connection flange; all joints and seams welded and/or liquid tight; all exposed welds ground
and polished to the original finish of the metal. Provide continuous full-length hanging brackets on each
unit for mounting as required by the model designated.

[ ]

Provide each ventilator with a UL/ULC listed self-closing, spring loaded fire damper assembly activated
by a listed fusible link rated at 286oF (141oC).

[ ] Provide a UL/ULC listed exhaust air volume control damper for optimum balancing of single and
118

Codes and Equipment Specifications
multiple ventilator systems accessible through the ventilator plenum c/w fire damper assembly.
[ ]

Provide water manifolds constructed of square, stainless steel tubing, and looped to provide equal water
pressure to all nozzles.

[ ] For hot water wash models, provide spray nozzles of machined brass.
[ ] For cold water mist models, provide spray nozzles of stainless steel.
[ ] Integrated make-up air shall be accomplished through the top of the ventilator at designated collars.
[ ] Hood size: Length ________ width _______ height _______
Services
[ ] Exhaust air ___________[ ] Static pressure ___________[ ] Collar size __________
[ ] Supply air ____________[ ] Static pressure ___________[ ] Collar size __________
[ ] Electrical: 120/1/60_______ watt
[ ] Direct connect to _______ junction box for lights (by electrical contractor)
Modifications and options
[ ] Lights - the ventilator shall contain - quantity _______
[ ] Flush mount fluorescent light fixtures 36” (914 mm) or 48” (1219 mm) long (2 x 40 watts).
[ ] Flush mount vapor proof incandescent light fixture (2 x 75 watts).
[ ]

Surface mount globe-type light fixtures complete with clear thermal shock-proof glass with plated steel
wire guard (1 x 100 watts).

[ ]

Drain manifold - for multiple sections to one common connection, complete with removable lower drain
enclosure.

[ ] Offset collar - (specify left or right of center line) duct collars __________.
[ ]

Taper - (on T models) specify taper required __________ to suit low ceiling. Standard is 12”(305 mm).

[ ] Stainless steel main back - where exposed, for island applications.
[ ] Rear duct - rear duct collar take-off.

119

Ventilation Systems

Water Wash Control Panels
Clear specification of electrical control panels is an important part of the total bid package consultants prepare
for any commercial kitchen project. VM offers two series of control panels for water wash equipment. These
are the H4-25 series for hot water wash equipment and the HC4-25 series for cold water mist with hot water
wash. The legend of optional selects for control panels is as explained in this table:
Base
Optional Mandatory Legend
Model Select
Select
H4-25
-S -R
S - surface mounted on wall;
HC4-25
-S -R
R - recessed in wall;
-24V
24v Ecology interlock
-2SQ
2SQ - two sequence wash;
-3SQ
3SQ - three sequence wash, etc.
-24HR
24 hour timer
-BFP
Back flow preventer cabinet
-BMS
Building management system controlled
-MP
Micro processor
-TPG
Temperature/pressure gauge
Example of Model designation: HC4-25-2SQ-24V-R - i.e, hot and cold water panel, size 25, double sequential
wash, 24 volt control interlock, recessed in wall.
Model

Cold
water
spray

Hot
water
mist

H4-25

--

x

HC4-25

x

x

Maximum ventilator length
Cyclo Maze wash

Cyclo wash

Feet

MM

Feet

MM

40

12192

25

7620

40
12192
Table 22

25

7620

ITEM #
For the ventilator specified, provide a VM wash control panel to provide:
[ ] Cold water supply to the ventilator
[ ] Auto wash down cycle with adjustable wash timer and low detergent alarm.
[ ] Include provision for electrical interlock with the fire alarm system and, in case of fire, to initiate the
wash cycle.
[ ] Automatic operation of the exhaust and supply fans in addition to the run and wash cycles of the
ventilator.
[ ] A selector switch with RUN and WASH indicator pilot lights and a low level detergent light.
[ ]

Hand shut-off valves on inlet and outlet, hot and cold water solenoid valves, detergent pump, wash time,
120

Codes and Equipment Specifications
wash time delay, low level detergent alarm, hot and cold water pressure reducing valves complete with
strainers, field adjustable wash timer.
[ ] For HC4 series panels, a cold water pressure gauge.
Construction
[ ] Provide a control panel body constructed of18 gauge stainless steel finish with a stainless steel hinged
lift off cover, and with separate plumbing and electrical compartments.
[ ]

For the initial charge of the detergent container, provide a 4-liter container of detergent for each control
panel supplied.

Trade notes
[ ] MECHANICAL: Supply and install back flow preventers, anti-syphon valves or vacuum breakers as
required by local codes. It is recommended that the control panel be located within 35 pipe feet (10668
mm) of the ventilator.
[ ] ELECTRICAL: Supply and install control field wiring and electrical devices required outside the
control panel. VM supplies field wiring diagrams on request. Power supply to be 120/1 /60 cycles.
Maximum control panel amperage during the wash cycles is 1 amp.

121

Ventilation Systems

Exhaust Fans
ITEM #
Construction
[ ] Supply [ ] grease extraction fans Garland GEF-A Series Model ________ (Specify model by air
volume, cfm, motor HP and static pressure as noted below.) The entire fan housing, cowl and discharge
shall be 16 gauge cold rolled steel, continuously welded and liquid tight to NFPA 96 requirements. The
unit(s) shall be complete with a 16 gauge cold rolled steel roof curb shipped separately for installation
in the field. Provide an exhaust duct collar of 1” (25mm) insulated double skin (16 ga. inner skin, 20
ga. outer skin) of welded cold rolled steel. The unit(s) shall extend 12” (305 mm) below the roof line
and have a 1.5” (38 mm) flanged connection for welding or bolting to the duct system. The minimum
clearance from the duct collar to combustible roof opening shall be 3” (76 mm) as per UL/ULC
approvals.
The fan wheel shall be all welded, statically and dynamically balanced at the factory with single inlet
and backward inclined blades to provide non-overloading characteristics and minimum noise level.
Bearings shall be grease lubricated, heavy duty self-aligning flange type, mounted outside of the air
stream on an oversized, polished steel shaft.
The unit shall be complete with a smoothly curved inlet venturi to create a streamlined air flow into
the fan wheel. The complete unit shall be factory primed and painted, ready for outdoor installation.
Electrical
[ ]

Provide an electrical disconnect switch (wired to the fan motor) and an electrical conduit sleeve that runs
the complete length of the duct collar. Provide a high temperature wire in the conduit to a point about
6” (151 mm) below the duct collar for electrical junction box hook- up below the roof line, indoors.

[ ] Provide an adjustable pitch (1 or 2 groove) pulley factory set at the proper operating speed for motors
up to 5 HP or a fixed pulley for motors over 5 HP.
Standard components
[ ] Provide unit(s) complete with a gravity back draft damper located at the fan discharge.
Approvals
The fan shall be AMCA rated and listed by the UL/ULC as a power roof ventilator for restaurant exhaust
systems.
Services
[ ] Exhaust air ____________(specify cfm requirement)
[ ] Static pressure__________(specify water gauge in inches)
[ ] Motor HP______________and voltage ___________

122

Codes and Equipment Specifications

EcoloAir/Ecology Systems
The VM EcoloAirTM Ecology system removes smoke, grease and odors. It is used in conjunction with water
wash or filter type hoods. It permits the use of duct work from the unit to a low level outdoor discharge. This
is an exception to the NFPA 96 Standard because of the high filtration efficiency of this continuously
self-monitoring system. The system is applicable to non-traditional sites to meet environmental requirements
where the use of an all-welded NFPA duct from the hood to the roof fan is not possible, when the cost of
all-welded ducting is prohibitive.
ITEM #
[ ] The EcoloAirTM Ecology shall be a Vent Master Model EF-___-A___-B UL/ULC Approved.
[ ] CFM capacity _________
[ ] CFM set for __________
[ ] Total static pressure ____________
[ ] External static pressure: filter inlet ________ fan discharge ____________
Construction
[ ] The unit casing shall be of double wall construction reinforced and braced for maximum rigidity. The
inner walls shall be 16 gauge liquid tight welded construction and the outer walls shall be of 20 gauge
steel minimum.
[ ] Provide a filter section insulated with 1.5” (38 mm) insulation to UL/ULC requirements.
[ ] Provide a unit with three stages of filtration. The first stage shall be a 4” (102 mm) pleated UL/ULC
bag filter rate at 40% ASHRAE 52-76. The second stage shall be a 22” (559 mm) UL/ULC bag filter
rated at 95% ASHRAE 52-76. The third stage shall be a 12” (305 mm) absolute filter UL/ULC rated
at 95% DOP to 0.3 microns. A UL/ULC listed fire damper actuated by a fusible link shall be located
at the outlet.
[ ]

Provide a unit complete with four pressure switches to monitor pre-filter, high efficiency filter, absolute
filter and overall filters.

Mechanical
[ ] Provide a fan housing constructed from heavy gauge cold rolled steel with all joints reinforced and
braced for rigidity. The fan shall have a DWDI backward inclined wheel with an AMCA rating mounted
on heavy duty ground and polished steel shaft. The bearings shall be pillow block units with lubrication
nipples.
[ ] Provide hinged access doors to permit easy access to the fan and motor.
[ ]

The entire system shall be UL/ULC listed and approved for clean air, low level exhaust for commercial
kitchen cooking.

[ ]

Provide a high temperature ”limit” sensor for emergency unit shut down and provide interlock to control
panel alarms.
123

Ventilation Systems

[ ] Supply V-belt drives of a capacity 25% greater than the motor horsepower.
Electrical
[ ] Supply a control panel constructed of heavy gauge steel for remote mounting with front locking screws
complete with timers, relays and lamps to indicate ”system on”, condition of pre-filter, bag filter and
absolute filter, filter missing, fire and odor reducing operation.
[ ] Supply control circuits to operate at 24V AC.
[ ]

Voltage ___________Phase(s)__________ HP ___________connection to fan compartment disconnect
switch.

[ ] Supply an EcoloAir automatic odor control system VM Model ”A1R” UL/ULC listed and NSF
approved with a reverse spray nozzle. Cabinet sizes: 16” (406 mm) wide x 11” (279 mm) deep x 32”
(813 mm) high, having a capacity of 5 imperial gallons (23 liters). The unit shall be constructed of 18
gauge satin coated steel, charcoal air dry enamel finish with a side hinged access door panel fitted with
a key lock and two security bolts; an air compressor that operates at 22 psi (152 Kpa) and having an
atomizing type spray nozzle. Provide a program control in the master control panel equipped with two
timers: a 0-20 minute cycle timer and a 0-20 second spray timer. Provide a poly plastic reservoir bottle
with a removable cap, transfer tubing and 5 gallons of liquid solution.
Options
[ ] Odor reducing system consisting of a liquid spray system with timers mounted in the remote control
panel to switch on, off and cycle control and provide for infinite adjustment.
[ ] Double odor reducing system.
[ ] Odor liquid low level alarm.
[ ] Split sections.
[ ] 24 hour timer for odor reducing sequence.
[ ] Access platform base.
[ ] Lift off panels (in lieu of hinges).
[ ] Fifth pressure switch for absolute filter monitoring (filter missing).

124

Codes and Equipment Specifications

Fire Protection (Sprinkler) System
The VM Suppressor water mist fire protection system is good for all types of cooking equipment under VM
ventilation equipment.
Models & Water Requirements
Suppressor
Model

Pipe
Size

Max.
Nozzl
es

Designed
nozzels
discharged

Min. water
vol. required
U.S. Gal. Liters

SU3-100

1.00"

8

2

15

57

SU3-125

1.25"

12

4

30

114

SU3-150

1.50"

20

6

45

170

SU3-200

2.00"

30

8
Table 23

75

374

Models & Options
Specify the model required in the sequence:

Legend
-EFO exhaust fan remains on
-FP fire pull
-FPR fire pull remote
-S Surface mounted on wall
-R Recessed in wall

Series model + mandatory select + optional
select
Example: Series SU3-150-S-FPR (see legend)
ITEM #

The fire protection system shall be a VM water mist fire protection suppressor system Model:
[ ] Series SU3-100-____-____
[ ] Series SU3-120-____-____
[ ] Series SU3-150-____-____
[ ] Series SU3-200-____-____
[ ]

Provide mandatory trouble indicating lights and audio alarm to indicate that system shutdown is a result
of the hand water valve being closed, system low water pressure or a fire condition.

Construction
[ ] The panel housing and hinged doors shall be of 18 ga. (min.) stainless steel; a backing plate of 16 ga.
(min.) galvanized steel; the piping of the fire extinguishing system shall be schedule 40 black iron; and
a watertight partition shall be provided between the plumbing compartment and the electrical
compartment. In the panel, provide these components.
• A keyed MAINTENANCE OVERRIDE SWITCH.
• Supervised manual shut-off valve.
• Pressure sensing switch to shut off fuel sources should sprinkler water pressure drop to
125

Ventilation Systems
unsafe levels.
Gas shut-off delay with battery back-up for momentary power outage.
Flow sensing switch for immediate fuel shut-off and alarm activation upon nozzle discharge.
Pushbutton gas valve reset.
Pressure gauge (sprinkler water line).
Status indicator lights for POWER ON and GAS ON with lights and audible alarm for FIRE
ALERT, LOW WATER PRESSURE and HAND VALVE CLOSED.
• Factory pre-piped, pre-wired and tested.






Listings and approvals
All fire protection (sprinkler) systems shall be UL/ULC Listed, conform to the requirements of NFPA 13
Standard, NFPA 96 Standard, and the UMC.
[ ] Approved by the New York City Board of Standards and Appeals.
[ ] City of Los Angeles Mechanical Inspection Department.

126

Codes and Equipment Specifications

Kiosk Ventilation System
The recirculating air kiosk ventilation system (KVS) is primarily for kiosk-type food court operations and
non-traditional sites where NFPA 96 duct work either cannot be installed or is exorbitantly costly. The KVS
can be a RH, LH, back or remote mount unit. For example, a Model KVS-8 right hand mount unit is identified
by the designation KVS-8-R. The chart following will assist designers in selecting the right KVS unit for the
job.
Unit Specification Chart
Model

CFM

Motor
HP

KW

Amps

DS
Switch

KVS-5-L, or -R

1100

2

24

70

100

KVS-5-B

1250 to 1800

3

24

70

100

KVS-5-REM

1250 to 1800

3

24

70

100

1500

2

36

105

175

KVS-6-B

1500 to 1950

3

36

105

175

KVS-6-REM

1500 to 1950

3

36

105

175

2000

3

48

140

175

2000 to 2250

5

48

140

175

KVS-8-REM
2000 to 2250
5
48
140
Legend
LLeft hand mount
RRight hand mount
BBack of hood mount
REM - Remote mounting of filter tower up to 30 feet away.
5S6S8 -5, 6 or 8 ft. long sections.
Table 24

175

KVS-6-L, or -R

KVS-8-L, or -R
KVS-8-B

ITEM #
The KVS shall be a Vent Master Model:
[ ] KVS-5 _______(specify -L, -R, -B or -REM)
[ ] KVS-6 ________(specify -L, -R, -B or -REM)
[ ] KVS-8________(specify -L, -R, -B or -REM)
[ ] The KVS shall be a UL/ULC listed system tested in accordance with NFPA 96, Chapter 10, and UL
197-1994 for integral recirculating systems for commercial electric cooking appliances.

127

Ventilation Systems
Construction
[ ] The system shall have a listed exhaust filter hood, complete with VM stainless steel GFIII UL listed
filters, mounted 6' 2” (1880 mm) from floor level. The filtration tower shall include a filter module, fan
and motor, fire protection, odor control system and electrical cabinet.
[ ] The assembly shall be stainless steel construction with all exposed welds ground and polished to the
original finish of metal. The system shall be fully self-supported, pre-piped and wired for a fully
automated operation, factory tested and balanced.
[ ]

The system shall be listed and approved for a total flood fire protection of the cooking equipment below
with a fixed nozzle distribution system.

[ ] The system shall provide the utility power distribution, interlocks and controls for the cooking
equipment.
Options
[ ] The filtered, clean air shall be discharged back into the cooking area through the air wall vents and/or
through the air register mounted on top of the unit.
[ ] The filtered clean air shall be discharged through a duct to outdoors.
[ ]

Lights - the hood section shall contain ______(specify the number) surface mount globe type fixtures.

128

Codes and Equipment Specifications

Utility `Modular' Distribution System
ITEM #
The MDS shall be a Vent Master Model:
[ ] MDS-W, Wall Style
[ ] MDS-I, Island Style
[ ] MDS-S, Raceway, no chases
The MDS shall be built to UL/ULC standards and conform to the NSF National Sanitation Foundation
Standards.
Construction
[ ] [ ] ft/m long, MDS of drip-proof construction using a minimum 18 ga., 304 stainless steel, No. 4 finish
with raceways and chases for mechanical and electrical services as herein specified. Install removable
panels for access to interior space to install and service the mechanical and electrical services. The use
of gaskets and sealants to make the unit drip-proof is not permitted.
[ ] Provide frame-mounted, full length bumper guards.
[ ]

Except as noted for circuit breaker (CB) panels below, provide secure fasteners on panels that must be
removed to give access to electrical components and services.

[ ] Provide a hinged, latching sub-door for access to the CB panel housing ON/Off switches and re-set
devices.
[ ] The services and supply lay-out is to match the cooking bank line-up specified and shown on the
drawings.
Mechanical Services
[ ] Provide pipe manifold support brackets of corrosion-protected 12 gauge steel, formed to accept
cushioned clamps of the correct size for each manifold. Each manifold shall traverse the full length of
the mechanical raceway. Supply a main quarter-turn shut-off ball valve for each piping service where
it enters the MDS. Using permanent tags that are not easily removed, label every manifold as to its
service; for example, `Hot Water', `Cold Water', `Steam', `Condensate Return'. Insulate the steam
delivery and condensate return manifolds.
[ ] Provide a [natural or LP] gas supply. A minimum Schedule 40 black iron pipe to be painted and used
for the gas manifold.
[ ]

For connection to the fire suppression system during installation, provide a solenoid to shut off the gas
supply should a fire occur.

[ ] Provide a cold water service having a fully insulated manifold of Type L hard-drawn copper.
[ ] Provide a hot water service having a fully insulated manifold of Type L hard-drawn copper.
[ ]

Provide a steam line and condensate return line with insulated manifolds of minimum Schedule 40 black
iron pipe. Pitch the steam supply manifold not less than 1/4” per 5' of horizontal run and connect a steam
trap. Connect the secondary side of the steam trap to the condensate return line 1/4” per 5' of horizontal
run to the building return end of the manifold.
129

Ventilation Systems

[ ] Provide an AGA/CGA quick-disconnect, plastic-coated hose set for each item of equipment requiring
gas or water connections.
[ ] Use restraining devices where equipment is on casters.
[ ] Mount a FILL faucet [specify type] at the peak of the raceway to serve these items of equipment:
[ ] Each unit that is part of this item shall be furnished complete with a prison package that shall consist
of keyed latches and tamper proof screws.
Electrical Services
[ ] The common requirements for electrical services shall be a raceway of adequate cross section for the
services being provided; a CB panel that meets regulatory code requirements for water-tight
applications; a main circuit breaker with a shunt trip for connection during installation to the ventilation
fire suppression system.
[ ]

Provide ground fault interrupters for electrical circuits rated 120V AC, 20A single phase and 208/240V
AC, 20A and 30A single phase.

[ ] In the mechanical chase, install a ventilator wash control station having RUN/WASH selectors with
indicator lights, a LOW DETERGENT light, audible alarm, 1/4-turn main shut-off valves, Y-strainers,
solenoid valves, detergent pump with TEST switch, PRESSURE TEMPERATURE gauge and
ADJUSTABLE WASH timer.
[ ] Provide ”suppressor” water mist fire protection controls for a main shut-off valve, LOW WATER
pressure switch; a pressure gauge WATER FLOW switch; and electronic controls to monitor system
operation and provide audible and visual indication of fire, low water pressure, and closed main shut-off
valve.
[ ]

Supply a battery back-up system to maintain the gas valve in the open position and maintain the exhaust
and supply latching circuit for five seconds during electrical power outages.

[ ] At each end of the MDS, provide EMERGENCY SHUT-OFF push buttons with red mushroom
head-type actuators to turn off the gas and electrical supplies.
[ ] Provide electrical cord sets or pre-wired seal-tight conduit as required.

130

Codes and Equipment Specifications

Heating/Make Up Air Unit
Packaged heating systems for roof-top mounting are used to meet make-up air or combination heating and
make-up air requirements. Gas-fired appliances are not designed for use in hazardous atmospheres containing
flammable vapors containing chlorinated or halogenated hydrocarbons.
The designation of VMRIG units (e.g., VMRIG 125) refers to the BTUH input as shown in the
accompanying data chart, Table 25.
Technical Data
125

250

400

500

BTUH input

125,000

250,000

400,000

500,000

Thermal capacity output

96,250

192,500

308,500

385,000

Unit current (less motor) at

1.9

1.9

1.9

1.9

115V

0.95

0.95

0.95

1.9

Control current (24V)

980 to

1960 to

3135 to

3500 to

AGA cfm range

1175

2350

3765

12,000

CGA cfm range

482

588

662

1104

Net. wt. in lbs.

622

817

930

1588

Shipping wt. in lbs

1/2"

1/2"

3/4"

1"

(2) 20 x 25

(1) 20 x 20

(2) 20 x 20

(1) 16 x 20

(3) 20 x 25

(1) 16 x 20

(1) 16 x 25

(1) 16 x 25

(4) 12 x 20

Gas connection (natural gas)
Filter size (filters are optional
and available in 1" or 2".

permanent or pleated)
(2) 20 x 25
(4) 12 x 25
Note:
AGA ratings for altitudes to 2000 feet. Above 2000 feet derated by orifice change, 4% for each 1000 feet above sea level. CGA
ratings for altitudes to 2000 feet. High altitude units (2001 to 4500 ft.) Are derated by 10% of maximum output.

Table 25
ITEM #
The heating/make-up air unit shall be a Vent Master
[ ] Model VMRIG 125.
[ ] Model VMRIG 250.
[ ] Model VMRIG 400.
[ ] Model VMRIG 500.
Construction and operation
[ ] The heater/make-up air unit shall have a weatherized, aluminized steel cabinet with a full curb cap for
mounting on a roof curb or supports.
131

Ventilation Systems

[ ] Specify a unit for use with:
[ ] Natural gas, or
[ ] Propane gas.
[ ] Specify a built-in power vent system, or
[ ] Specify a gravity-vented unit.
Controls
[ ] Supply limit and safety controls certified by the AGA and approved by the CGA and bearing the AGA
or CGA label.
Options
[ ] A bottom discharge air opening with the addition of a downturn plenum.
[ ] Bottom air inlet with specified option damper control system.
[ ] Cooling coil cabinet.

132

Trouble Shooting

Trouble Shooting

Kitchen ventilation manufacturers should provide extensive installation,
operating and maintenance instructions for the equipment and systems they
supply. Instructions, however, are often found missing when needed. This
trouble shooting guide, therefore, is a general one only and cannot more than
supplement particular system instructions. It lists the common causes of faults
in systems and recommends the response.
The guide is in alphabetical order of topics and components. We
recommend that readers use it as a reminder as to the causes and recommended
responses to problems that arise.
Actuators/Damper Motors
Trouble
Not in proper position.

Cause
Off its set point position.

Response
Make sure set point is correct.
Do the controller and sensor set
points agree?
If this fails to correct the
condition, re-calibrate the
controller.
If the controller is correct, check
the actuator.

Suspected faulty sensor.

Open or short circuit.

Disconnect leads to the controller.
Check for open circuit (above
2000 ohms) and short circuits. If
either condition is found, replace
the unit.

133

Ventilation Systems

Air-conditioning systems
Trouble
HP too high
(High amp readings).

Low CFM

Cause
Fan speed above design.

Fan wheel installed backwards.
Correct.

Fan rotates backwards.

Correct rotation.

Loose wire connections.

Correct.

Fan running backwards.

Correct (i.e., reverse two
connections of the 3-phase power
supply).

Fan RPM too low.

Investigate and adjust fan speed.

System resistance too high.

Find and correct cause.

Variable inlet vanes partially
closed.

Check inlet vanes and readjust.

Access door open.

Close the door and re-lock.

Scroll bypass damper open.

Close the damper and readjust.

Fan RPM too high.

Adjust fan speed.

System resistance below design.

Correct the fault and/or adjust the
hood balancing damper.

Fan wheel installed backward.

Remove and re-install.

Leaks or obstructions in the duct
system.

High CFM.

Response

Bearings
Trouble
Running hot or noisy or both.

Cause

Response

Lubrication.

Check lubrication - too much or
too little.
Excessive belt tension.

Poor alignment.

Correct alignment.

Distorted shaft.

Correct shaft eccentricity.

Loose mounting or housing.

Tighten.

Seals misaligned.

Correct or replace.

Dirty.

Remove and clean.

Bearing worn.

Replace.

134

Trouble Shooting

Couplings
Trouble
Running hot and noisily.

Control devices (electronic)
Trouble
Faulty operation.

Cyclo-Wash Units
Trouble

Cause
Coupling unbalanced.

Cause

Response
Correct alignment.
Lubricate.

Response

Incorrect output signals.

Note: These references to
equipment controller problems are
general. The best advice is to
consult the supplier literature of
the particular controller. This is
especially important regarding set
points and output signals.

Note interlocked with control
panel.

Have a control technician check
the control circuitry against
specification and correct if faulty.

Cause

Response

Water leaking from bottom of unit. Drain manifold loose.

Tighten union and add plumbing
tape if necessary.

Water leaking from above unit or Leaking ductwork connected to
from the light fixture.
hood.
Leaking plumbing connected to
hood.
Water supply lines sweating.

Make the ductwork watertight.

Ventilator not draining properly.

Clean chamber and drain line.

Foreign material in extractor
chamber or drain line.
Ventilator not plumb and level.
Drain line too small.
To many 90o turns and/or P trap
added.

135

Service the plumbing holding
brackets and joints.
Insulate lines.

Plumb and level unit.
Floor drain line should be 1” larger
than ventilator drain line. Correct.

Ventilation Systems

Trouble
Insufficient water.

Cause
Low water pressure.

H & C water lines not properly
flushed following installation.
Nozzles plugged.
Unit not cleaning properly.

Response
Check supply pressures: 30 psi for
cold water and hot water.
Clean all strainers and nozzles.
Ditto - clean nozzles.

Unit out of detergent.

Refill detergent tank and check
operation of pump.
Wrong detergent formula.
Change to detergent
recommended.
Water not hot enough.
Check water temperature, which
must be 120o to 180oF.
Hot water line pressure too high. Reduce pressure to 30 psi max.
(High pressure dilutes detergent.) (May require addition of
reducing valve outside panel.)

Ventilator not capturing smoke and Inadequate exhaust air capacity.
odor.
Blower inadequate.
Blower operating backwards.
Drive belt slipping.
Dampers closed.
Make-up air inadequate or
improperly introduced.

Check capacity against
specification.
Check static pressure against
specification and correct.
Change wiring to reverse direction
of blower.
Tighten or replace belt.
Replace fusible link.
Check make-up air and flow
against specification and correct.

Exhaust fan not running; no cold
water.

No power.

Check power supply at panel; fuse
or breaker overload.

Exhaust fan runs; no cold water.

No cold water to panel.
Hand valve in panel closed.
Clogged line strainer.

Check water supply to panel.
Open valve.
Clean strainers in panel and unit.
Turn switch to RUN position.
Solenoid should click. Replace if
faulty.

Defective relay or cold water
solenoid.
When RUN switch is on, fan starts, Defective switch or relay.
but will not keep running.
Defective motor or breakers.

136

Make electrical check. Clean
contacts. Replay items if defective.
Check amp readings and correct.

Trouble Shooting

Trouble

Cause

When switch is in WASH position, No hot water to panel.
fan stops, but no hot water (after
60 second delay).
Hand valve in panel closed.
Dirty water strainer.
Defective hot water solenoid.

Timer relay defective.
Timer relay dial turned to zero.

Response
Check and ensure main water
supply.
Open hand valve.
Clean strainer in panel.
Switch on WASH. If no ”click” of
solenoid replace as needed.
Replace.
Set dial indicator for 2 1/2 min. for
CWCH; 5 min. for CWH.

When switch is in WASH position, Dirt in cold water solenoid.
fan stops and cold water continues
to run.

Clean solenoid.

Hot water continues to run when
wash cycle ends.

Dirt in hot water solenoid.

Clean solenoid.

Buzzer sounds when washing.

LOW DETERGENT alarm.
Air in detergent line.
Setting of LOW DETERGENT
switch.
LOW DETERGENT switch
defective.

Refill container.
Re-prime pump.
Adjust screw on switch.

Cracked tubing.

Replace tubing.

Loose vent plug.

Tighten plug.

Fittings over-tightened.

Hand-tight fittings are sufficient.
Make sure they are no more than
hand-tight.

Back pressure in the line.

Check and adjust the water
pressure.

Detergent in control panel is
leaking.

Test and replace switch if
necessary.

Check the anti-syphon valve for
wear and replace if needed.

137

Ventilation Systems

Trouble
Detergent pump will not prime.
(Consult the section on pump
priming.)

Cause
Back pressure in line.

Response
Check water pressure. If it exceeds
40 psi, add regulator.

Worn or clogged fittings in suction Check tubing and fittings for
or discharge lines.
debris and clean.
Worn diaphragm.

Flush system with hot water and
replace defective fittings or
diaphragm.

Vent plug not tight.

Tighten plug and O-ring for
sealing.

Pump cam set at zero.

Adjust cam to specification.

Incorrect detergent.

Use recommended detergent.

Fan and motor drives (also see electric motors)
Trouble
Cause
Vibrating and noisy.

Response

Sheave loose on shaft.

All the reasons given here as
V-belts striking guards or shields. possible causes for poor
operation stem from mechanical
V-belt tension incorrect.
faults. Correct the fault and defect
V-belts of incorrect size.
identified.
Unmatched V-belts.
Misaligned mechanical parts.
Belts oily, dirty or worn.

Electric motors
Trouble
Fails to start.

Cause

Response

Blown fuses or tripped
breaker

Check for short circuit before
replacing fuses or re-setting
breaker.

Overloads trip.

Motor overload. Check cause and
re-set.

Open circuit.

Check power supply and for loose
connections.

138

Trouble Shooting

Trouble
Motor stalls.

Cause

Response

Single phasing.

Check lines for open phase.

Mechanical overload.

Find cause and correct.

Undervoltage.

Check supply voltage.

Motor starts and stalls.

Power failure.

Check power supply.

Fails to reach speed.

Low voltage.

Check voltage line drop.

High starting load.

Check mechanical loading.

Open primary circuit.

Check the incoming lines.

Wrong rotation.

Wrong phase sequence.

Change two phases.

Motor overheating.

Mechanical overload.

Reduce the load

Inadequate ventilation.

Clean air vents and passages.

Unit single phasing.

Check lines for open phase.

Unit misaligned.

Re-align.

Mechanical fault.

Check bearing alignment.

Air gap not uniform.

Check for worn bearings.

Rotor out of balance.

Re-balance or replace motor.

Noisy operation.

Fans
Trouble
Impeller hitting inlet ring or
housing.

Cause
Impeller not centered in inlet ring.
Inlet ring damaged.
Crooked or damaged impeller.
Shaft loose in bearing.
Impeller loose on shaft.
Bearing loose in housing.

139

Response
Again, these faults listed are
possible causes of fan units that
run roughly and noisily. Check the
possible causes and correct these
mechanical faults accordingly.

Ventilation Systems

Trouble
Fan running noisily and
vibrating.

Cause

Response

Unit running out of balance.

Left to run, an unbalanced fan
will eventually result in
mechanical damage. Re-balance
the fan to restore its smooth
operation.

Fan blades cracked or
damaged from mechanical
interference.

Seek and eliminate cause of
mechanical interference and
replace damaged blades.

Impeller loose on shaft.

Check and secure the impeller
locking.

Worn impeller blades.

Remove abrasive, corrosive or
otherwise loose material from air
flow passages.

Shafts
Trouble
Unstable performance.

Shaft squealing.
Shaft overheating.

Cause

Response

Shaft bent.

Check for eccentricity.

Defective bearings.

See Bearings.

Shaft misaligned.

Re-align.

Lubrication.

Lubricate.

Shaft misaligned.

Check and re-align seals.

Poor lubrication.

Lubricate.

Seal failure.

Replace.

140

Engineered Features

Engineered Features

Engineering designs and modular equipment packages are an important aid to the
architect and kitchen designer. The result of years of experience working in the
field of kitchen ventilation systems, modular kitchen equipment packages help
solve problems encountered both in new kitchen designs and renovations.
Ventilation problems are often found in dealing with non-traditional site exhaust
systems, in life cycle costing assessments, and when considering the economics
of recirculating clean air systems. The purpose of this section is to discuss the
key features that architects, engineers and designers should look for regarding
product design.
The best product and kitchen system design should:






Simplify construction and installation requirements;
Reduce operating costs;
Make maintenance and servicing easier;
Provide efficient ventilation; and
Improve ventilation balancing and flexibility to meet changing conditions.

Typical engineered equipment packages
Many engineered equipment packages are available for use in commercial
kitchens. The following engineered packages are typical of those offered in the
design of new commercial kitchen sites or in the renovation of existing ones:
• Kitchen exhaust hoods - filter, dry Extractor and water mist/wash
• Kiosk recirculating equipment
• Ecology/clean air equipment
• Exhaust fan equipment
• Prefabricated roof curbs
• Make-up air distribution plenums
• Fire protection systems
141

Ventilation Systems

• Control systems
• Make-up air units
• Utility distribution equipment
In the pages that follow, the key features of the equipment packages listed above
are shown and advantages highlighted.

Hoods
Key features to look for
Each hood type should provide the highest grease removal
efficiencies with the lowest operating static pressures












Dry or water wash available in all
stainless steel 300 series construction
Adjustable volume control dampers
and air baffles
Up to 16 ft. length single piece construction
Cold water mist grease
removal system
Full length hanging brackets (front and rear)

Allows each hood to have its total air adjusted
Provides initial installation savings
Reduces wash down costs by over 50% and
provides the greatest fire safety with the cleanest
ducts and roofs
Simplifies and reduces installation costs

142

Engineered Features

143

Ventilation Systems

144

Engineered Features

145

Ventilation Systems

146

Engineered Features

147

Ventilation Systems

148

Metric Conversion Chart

149

150

Abbreviations
ICBO

International Conference
Building Officials
KG or Kg
Kilograms
KPA
Kilopascals
KVS
Kitchen ventilation system
KW or kw
Kilowatts
LB or lb
Pound weight
M
Meter (unit of length)
Max.
Maximum
Min.
Minute or minimum
MDS
Modular distribution system
NFPA
National Fire Protection
Association
NSF
National Sanitation
Foundation
OPN
Open area of intake
PA
Pascal
PSI
Pounds per square inch
REM
Remote
RPM or rpm Revolutions per minute
SBCCI
Southern Building Code
Congress International, Inc.
SP
Static pressure
s/s
Stainless steel
Temp.
Temperature
TPG
Temperature/pressure
gauge
UL
Underwriters' Laboratory
ULC
Underwriters' Laboratory
Canada
UMC
Uniform Mechanical Code
Vol.
Volume
V
Volts or voltage
VM
Vent Master
WG
Water gauge

AC
AGA
AMCA

Alternating current
American Gas Association
Air Movement
and Control
Association, Inc.
Amp
Ampere
ASHRAE
American Society of
Heating, Refrigeration and
Air Conditioning Engineers
ASTM
American Society for
Testing and Materials
AWG
American wire gauge
BOCA
Building Officials and Code
Administrators International, Inc.
CFM or cfm Cubic feet per minute
CGA
Canadian Gas Association
CM or cm
Centimeter
C/W or c/w Complete with
CWCH
Cold wash, cold water mist and
hot water wash
CWH
Cyclo Wash, hot water only
DC
Direct current
DWDI
Double width double inlet
EPA
Environmental Protection
Agency
EVS
Engineered ventilation
system
Ft. or ft.
Feet
FPM or fpm Feet per minute
Ga or ga
Gauge
GPM or gpm Gallons per minute
HEPA
High efficiency particle
absorption
HP
Horse power
HVAC
Heating, ventilating and air
conditioning
151

of

of

152

Bibliography

ASHRAE

Developments in Kitchen Ventilation Technology, Technical DataBulletin,
Volume 8, Number 4

ASHRAE

Heating, Ventilating, and Air-Conditioning Applications, 1995 ASHRAE
Handbook

AMCA

Air Movement and Control Association Inc.

ASTM E-1993

Standard Test Method for Behavior of Materials in a Vertical Tube
Furnace at 750o C.

BOCA

Building Officials and Code Administrators International, Inc.

EPA

Environmental Protection Agency

EPA

Test Method 202, Determination of Condensible Particulate Emissions for
Stationary Sources

NFPA 10

Standard for Portable Fire Extinguishers, 1990 edition.

NFPA 12

Standard for Carbon Dioxide Extinguishing Systems, 1993 edition.

NFPA 13

Standard for Installation of Sprinkler Systems, 1994 edition.

NFPA 16

Standard for Installation of Deluge Foam-Water Sprinkler and
Foam-Water Spray Systems, 1991 edition.

NFPA 17

Standard for Dry Chemical Extinguishing Systems, 1990 edition.

NFPA 17A

Standard for Wet Chemical Extinguishing Systems, 1990 edition.

NFPA 54

National Fuel Gas Code, 1992 edition.

NFPA 58

Standard for the Storage and Handling of Liquefied Petroleum Gases,
1992 edition.

NFPA 70

National Electrical Code, 1993 edition.

NFPA 80

Standard for Fire Doors and Fire Windows, 1992 edition.

NFPA 96

Standard for Ventilation Control and Fire Protection of Commercial
Cooking Operations, 1994 edition

NFPA 211

Standard for Chimneys, Fireplaces, Vents, and Solid Fuel-Burning
Appliances, 1992 edition

UL 723

Test for Surface Burning Characteristics of Building Materials.

UMC

Uniform Mechanical Code
153

154

Index

INDEX
Air flow
available options, 38
calculations, 40
CFM calculations, 39
CFM requirements of hoods, 40
down discharge supply, 36
front panel make-up air, 37
limitations of exhaust and make-up air, 37
make-up air, 35
negative pressure, 39
short cycle supply, 36
Auxiliary Equipment
features of the MDS, 51
Kiosk ventilation systems, 54
Auxiliary equipment
air balancing, 45
dampers, 45
electrical equipment, 45
fans, 46
fans for multiple kiosks, 96
heat exchangers, 48
Modular Distribution Systems, 50
Backshelf hood, Clearances, 12
Calculating velocity, example, 43
Canopy hood, Clearances, 12
ASHRAE filter specifications, 113
BOCA, 111
Ecoloair/Ecology filter guide, 114
filter ratings, 112
NFPA 96, 105
odor control, 114
technical specifications, 111
UMC, 111
Codes and standards
auxiliary clean air filtration, 112
building regulatory provisions, 105
filter specifications, 113

need for exhaust, 106
NFPA 96, 110
Regional code requirements, 107
Baltimore, Maryland, 108
Denver (City & County), 109
Florida, 110
Los Angeles, California, 110
Nevada, 110
New York, 107
State of Michigan, 108
Cyclo-type units, Velocity readings,42
Cyclo-wash units, trouble shooting guide, 135
Design
assessment, 88
calculate make-up air, 89
checklist, 92
elements of ventilator design, 87
equipment placement, 91
factors governing choice, 91
odors, 89
options, 90
reference source, 89
sound levels, 92
sources of heat, 92
types of filtration technologies, 79
types of installations, 83
use of space, 89
Ducting
duct cleaning, 30
duct installation clearances, 31
duct openings, 30
exhaust terminations, 34
exterior installation, 32
general consideraitons, 29
installation, 31
interior installation, 32
ventilation rates, 30
Ecoloair filtration system, 102
benefits, 103

155

Index
listed grease extractors, 59
nozzles, 58
pipe sizes, 56
surface fire protection, 58
water mist systems, 58
water sprinkler systems, 56
wet chemical systems, 55
Fire suppressor systems, Installation
& Design Requirements, 63
Food court applications
comparison chart cfm vs leased area, 96
exhausting multiple kiosks, 96
Greader removal devices, extraction rates, 23
Grease devices, extraction rates, 23
Grease extraction devices
air flow in Cyclo Maze cold water mist, 25
air flow in Cyclo Maze dry unit, 24
Cyclo Maze series, 24
hood engine specifications, 27
types of extraction engines, 26
unit as an engine, 25
what makes units efficient, 26
Grease extractors, 16
Grease removal devices, 23
Hoods
backshelf, 12
canopy, 12
CFM calculations, 41
CFM correction factors, 41
equipment lay-out, 13
filters, 16
height limitations, 14
incremental lengths, 14
nomenclature, 11
sizing, 13
wall locations, 13
Installation
listed grease extractors electrical controls, 70
ranges, griddles, hot tops and plates with
high shelves, 66
Intake velocity measurements, 43
Listed grease extractors, U. L. tests, 60
Maintenance, Cyclo-wash 3, 75

handling capacities, 102
modular construction, 103
Ecolair system
solution mixing instructions, 113
sound levels, 63, 92
EcoloAir Systems, Installation
Design Requirements, 61
Engineered features
air make-up systems, 148
clean air exhaust systems, 144
grease exhaust fans, 147
hoods, 142
recirculating head systems, 143
sprinkler fire protection, 145
typical equipment packages, 141
utility distribution systems, 146
Equipment specifications, 115
Ecoloair/ecology systems, 123
exhaust fans, 122
filter hoods, 116
fire protection (sprinkler) system, 125
Kiosk ventilation system, 127
Modular distribution system, 129
water wash control panels, 120
water wash hoods, 118
Exhaust air
calculating volumes, 13
velocity, 13
Exhaust hoods, Factors affecting
grease removal, 25
Filters, 23
Fire dampers, 45
NFPA 96 on dampers, 59
opinions, 58
Fire protection
automatic duct protection, 60
certification, 70
dry chemical systems, 55
fire dampers, 58
general requirements, 56
Jurisdiction & inspection, 56

156

Index
actuators/damper motors, 133
air-conditioning systems, 134
couplings, 135
Cyclo-Wash units, 135
electric motors, 138
fan and motor drives, 138
fans, 139
shafts, 140
Types of filtration technologies
active carbon filters, 81
catalytic conversion, 81
electrostatic precipitators, 80
incineration, 81
liquid odor control, 82
oxidizing pellet bed filters, 81
pleated or bag filters, 81
water mist, waterfall, and water bath, 80
Velocity calculations, 42
Ventilation at different sites, 9
Venting cooking equipment, 39
Why ventilation is essential, 39
Work processes, 7, 8, 9, 10

Odor control, 86
categories of odor, 48
filtration systems, 48
liquid odor solution, 87
special odor problems, 87
Procedures, Warnings, cautions & notes, 9
Sprinkler nozzle
conveyor broiler, 69
duct protection, 70
plenum protection, 69
test valve, 70
tilt fry pan, 68
upright broiler, 68
Sprinkler nozzles, 63, 65
nozzle temperature rating chart, 63
ranges, griddles, hot tops and plates, 66
salamander broiler, 67
System capacity factors, 11
Terms and definitions, 21
Trouble Shooting, Bearings, 134
Trouble Shooting

157

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