Lesson Learned - Copy

Published on December 2016 | Categories: Documents | Downloads: 45 | Comments: 0 | Views: 276
of 7
Download PDF   Embed   Report

Comments

Content

Page 1 of 7

Using Revit MEP to Calculate Flows For Sizing Duct & Pipe Over the course of the last few Revit MEP projects I have been able to use the information in the models to calculate flows which have assisted with sizing duct and pipe. Based on what I have found this has made the process productive and eliminates the need to calculate everything on paper. It has also made it easier to adapt to changes as the design process evolves. I will advise that this works well on simple projects. It can get challenging when applying to more complex designs. This information is intended to show the capabilities of using Revit MEP for these calculations. An intermediate understanding of Revit MEP and some extra training is recommended.

How It Works: Revit MEP is doing these calculations based off the duct and pipe connectors inside the families. The connectors have properties for Supply Air, Return Air, Exhaust Air, Hydronic Supply, Hydronic Return, Domestic Cold Water, Domestic Hot Water and Sanitary system types. Depending on the system type and flow stream, the connectors are set up in different ways to calculate CFM, Fixture Units & GPM.

Lessons Learned: y y y Everything must be connected. No exceptions! Depending on the source of the Revit MEP family, the connectors might need to be edited in order to calculate accurately. Lavatories, Water Closets, Urinals, Mop Basins, Service Sinks and Drinking Fountains are typically in the architect s model. For this reason I have created connector placeholder families with type parameters for Cold Water Fixture Units, Hot Water Fixture Units, Waste Fixture Units and Diameter of pipe. Ideally these should be set up at the beginning of the project to match the Plumbing Fixture Schedule and the fixture load based on the IPC. Hot Water Circulation systems are not currently available in Revit MEP. I used a separate Domestic Hot Water system for the Hot Water Circulation. Vent systems are not currently in Revit MEP. I used a separate Santiary system which calculates waste fixture units for the Vents. Lengths will need to be manually added up for sizing. Duct, Hydronic and Domestic Water systems need to be closed. Any open ends need to be capped. Sanitary systems need to have one open end. The open end is typically the pipe leaving the building. Creating information schedules has been a great way to manage the parameter in the families. Some scenarios need to be calculated manually. For example, complex duct and piping in a mechanical room. These systems have proven to be accurate if they are set up right. For example, if you click on a duct or a pipe and the flow is 0 that means something is not connected or there is an opening in the system somewhere. It could also mean that the connectors in the family are not set up right.

y y y y y y y

Page 2 of 7

Calculating CFM s and Sizing Duct: Revit MEP is able to calculate the airflows thru ducts back to the terminal unit based on the CFM entered into the diffusers. It can then calculate the total airflows from all the terminal units systems and calculate them thru the main duct to the Air Handling Unit. In the image below the airflows are entered into the diffusers and all the duct is connected back to the terminal unit. Revit MEP automatically calculates the CFM s all the way thru the duct back to the terminal unit. You can click on a duct anywhere in the system and see the calculated airflow. This information can then be used to size the duct.

Page 3 of 7

Calculating GPM and Sizing Hydronic Pipe: Revit MEP is able to calculate the GPM thru pipes from the terminal units back to the mechanical room. In the images below the GPM s are entered into the terminal units. Revit MEP calculates the GPM all the way thru the pipe back to the mechanical room. You can click on a pipe anywhere in the system and see the calculated GPM. This information can then be used to size the pipe. If a GPM changes on a terminal unit you can go to the schedule and change the flow. Then go back to the model, view the calculated GPM and change the size if necessary.

Page 4 of 7

Calculating Fixture Units/ GPM for Sizing Domestic Water Pipe: Revit MEP provides a general conversion from Fixture Units to GPM using the values from the 2006 International Plumbing Code (IPC). It does this for both Flush Tank and Flush Valve systems. This will work for Domestic Cold Water, Domestic Hot Water and Hot Water Circulation systems. Note: The Plumbing Fixture Connector Types need to be set up with the Fixture Units at the beginning of the project. I created a separate Domestic Hot Water system for the Hot Water Circulation since revit does not currently have a system type for HWC. The image below shows the mains coming into the mechanical room. The GPM totals shown are calculated from all the Fixture Units in the building. (From top to bottom: CW, HW, HWC)

You can click on a pipe anywhere in the system and see the calculated Fixture Units and GPM. This information can then be used to size the pipe. If a fixture is removed or you have to re-route piping you can view the calculated GPM and change the size as necessary. Here you can see the Fixture Units [86.5] being converted to (63.2) GPM using Predominantly Flush Valves.

Page 5 of 7

Calculating Fixture Units for Sizing Sanitary & Vent Pipe: Revit MEP will calculate Fixture Units thru sanitary pipe based on the Fixture Units assigned to each fixture family. Note: The Plumbing Fixture Connector Types need to be set up with the Fixture Units at the beginning of the project. I created separate Sanitary systems for the Vents since revit does not currently have a system type for Vents. In the image below shows the total Fixture Units in the Sanitary pipe leaving the building. Revit MEP automatically calculates the Fixture Units all the way thru the pipe to the open end leaving the building.

You can click on a pipe anywhere in the system and see the calculated Fixture Units. This information can then be used to size the pipe. If a Fixture Unit changes on a fixture or you have to re-route piping you can view the calculated Fixture Units and change the size as necessary. Here you can see there are 93 total Waste Fixture Units for this bathroom.

Page 6 of 7

The same applies to the vents for this bathroom. Note: I still had to manually click on the vent pipes to see length in the properties .

Duct & Pipe Flow Legends: The image below shows a Duct Supply Flow Legend. It is an editable legend that will apply colors to ducts based on the flow. I was able to use this to help size duct based off the flows calculated from a Ductulator.

Page 7 of 7

The images below show a Domestic Water Flow Legend. I was able to use this to help size pipe based off the sizing chart calculated in the Excel DW Service Calc.

Sponsor Documents

Or use your account on DocShare.tips

Hide

Forgot your password?

Or register your new account on DocShare.tips

Hide

Lost your password? Please enter your email address. You will receive a link to create a new password.

Back to log-in

Close