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.