Fire Station FTE

Can you verify that FTE requested in PI form 3 is actually FTE per shift? The goal is to describe how many employees are typically working in the building at any single time, not the FTE equivalent of all shift work added together? FTE per shift makes more sense in terms of parking requirements , bicycle use, etc., although the FTE of all shifts added together might make more sense for overall water use. I am doing a fire station, which will be manned by 3 shifts of 3 firefighters each. Each shift works for two days straight, 24 hours a day, and then has 4 days off. Shift changes happen every other day at 7 am. A typical shift is 49 hours, counting the 1-hour overlap. Average hours worked per week varies, since the week has 7 days but the shift rotation is 6 days. For example, if a shift works Sunday and Monday on a given week it will also work on Saturday that same week. If I follow the suggested formula, I would describe 2 shifts of 49 hours and one shift of 73 hours to cover the whole week. This would give a FTE of [(49*2 + 73)/40]*3 = 12.8. However, this number seems meaningless, since it has no relationship to the number of people actually in the building. There are only 3 firefighters in the building typically; 6 firefighters at the shift change overlap. How would you suggest I describe this in Plf3-1?