22 Apr Tips & Tricks: Calculating Minimum Plumbing Fixtures Required with REVIT
With a few commercial projects in development here at Hayne, we have been spending time reviewing the Building Code (thank you UpCodes!) to calculate occupancy and minimum plumbing fixtures required. When we worked in AutoCad this would be completed as a separate calculation, maybe in the floor plan file or in an excel file. This would require us to update the input and calculations as the design evolved or changed.
With BIM and REVIT, we have developed a system to calculate this information through the use of Area Plans and Area Schedules! This means that as the design changes or the jurisdiction requests an occupancy change to a portion of the project, or we work through value engineering we only need to update ONE set of drawings … the Area Plans!
Let’s take a look at our project in Colorado to see the system work.
This is a snapshot of our main level Occupancy Area Plan. We created custom Area Tags that included the Occupancy, the Occupancy Load Factor, and the Number of Occupants per space.
Some spaces per the code are not calculated by area, but by the number of seats in the space or the length of the fixed seating. For our Steam and Sauna areas, we used a seated person in plan to show the proposed maximum occupancy.
We edited the legend to use patterns rather than colors because these plans will be printed and submitted in the main package for approval.
We created an area schedule that displayed the Occupancy and the total occupants so that we can start to breakdown required plumbing fixtures. We needed to first breakdown the total occupants into men and women at a ratio of 50/50. Then we can start to create custom fields to determine the number of water closets (WCs), lavatories (LAVs), drinking fountains (DFs), and others (typically service sinks). We used custom number fields to input the ratios defined by code.
We created calculated values to multiply either the Total Occupants or the Male/Female Occupants by the ratio per code. This gave us the total number of required fixtures.
Now we have a system that will update the required number of fixtures based on the occupancy. Any change made to the Occupancy Area Plan will be automatically updated in this table. Per code, buildings with multiple occupancies are calculated per occupancy, added, AND then rounded. This means that we will need 7 water closets on this site for women, not 10 if each individual category was added together.
Sometimes, you just got to LOVE BIM! I hope you find this method helpful as you set up your own REVIT files.
