My retail project is a grocery store that 24,955 SF. It operates for a 17-hour day. We established a predicted occupancy based on statics from a previous project. We have 90 FTE's over a 17-hour day (27 FTE peak over 4 overlapping shifts), and 2264 peak retail customers over the same period of time.
Clearly all of the FTE's and retail customers are not there all at once for calculation used by ASHRAE 62-1 or any other ventilation code.
Do I calculate FTE's for just an 8-hour window? What about the retail customers, is that just one hour of time?
And how is this to supposed to match WEp1 /WEc1? Appreciate any guidance.
Tristan Roberts
RepresentativeVermont House of Representatives
LEEDuser Expert
11475 thumbs up
December 28, 2018 - 7:00 pm
Cindy, I'm a little confused about your focus on FTE count for ASHRAE-62. You should use ASHRAE's rules for compliance, which would typically be undertaken by your MEP, not LEED rules for counting FTEs. I would not worry about matching FTEs from ASHRAE-62 to WE credits, no.
Cindy Davis
Manager, Sustainable DevelopmentUnico Properties LLC
January 2, 2019 - 12:41 pm
This is good to hear Tristan, and that is exactly the approach we took (202 peak occupancy based on ASHRAE 62 tables/calcs). Unfortunately it is the LEED reviewer that questioning why our occupancy count doesn't match up!
The reviewer's comment is: "The total peak occupancy of 202 people documented for this prerequisite [Min IAQ Performance] varies substantially from the total building users of 2,264 people [this is the total peak retail customers over a 17-hour day minus the employees or regular building occupancy] reported in the narrative provided in PI Project information. The peak occupancy should be reported consistently among credits. Confirm the appropriate peak occupancy for the building and update the peak occupancy and/or the diversity so the peak occupancy is consistent among all credits or provide a detailed narrative describing the difference in occupants." (which I did explain in detail why this varied so much in the PI Project Information).
So you would never have all 2264 retail customers there at the same time, right! The way I explained it is that a peak 8-hour shift would have an avg. of 175 'retail customers' (per hour) with the remaining 9 hours of operation averaging 96 customers per hour (or daily avg of 133 retail customers per hour) + 27 FTE's (peak shift of 4 overlapping 8-hour shifts) for a total of 202. And this is what I explained. So I'm not sure how they're expecting this to ever match up. What would you do?