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Forum Categories BOMA 2017 - Office Buildings Question

USF / RSF floor area calculations

Candice Bigley: PMB; February 5, 2021

We’re a multi-tenant building using method B calcs in a building constructed in 2016/2017. We established a 15% core factor to calculate the RSF.

For example if the suite is 1,000 USF then it is 1,150 RSF.

We just completed a new TI and the architect is subtracting the Vertical Service Area (VSA). Which are columns in the shell space that house vertical waste lines and roof drains. My question is in the past we have always included these “columns” when measuring the USF. I doubt we included this in our 2016 calc when figuring out the 15% core factor (otherwise the core factor could have been higher).

For older buildings can we include the columns in the USF when they were not accounted for in the core factor percentage.

In the future, what is the correct way to calc the core factor to get the RSF and correct USF?

David Fingret: Extreme Measures Inc.; February 8, 2021

Hi Candice,

The intention of the standard is that structural elements like columns are ignored and therefore included in the area that they exist in. However, a vertical shaft that is used for drains, etc. should be a Major Vertical Penetration (Vertical Service Area) and excluded from rentable area. I wouldn't consider such vertical shafts as columns since they are not structural. Also, the age of the building is not considered.

I hope this helps.

Thanks,
David