Dear All,

The following is the procedure i use to calculate unmet hours:

1)??? Percentage of Plant and system unmet is got from BEPU report.?

2)??? The number of hours fan is on is got from SS-E report.?

3)??? Percentage of system unmet(BEPU) multiplied by number of fan on hours(SS-E) gives the Unmet hours.

4)??? Plant and system unmet together should not exceed 300 hours.

But as per ASHRAE 90.1, the 300hours of unmet is w.r.t. a simulation for 8760 hours. If the building is only 8 hours working 5 days a week, then the fan on hours vary. Will the same 300 hours hold good for 3500 hours of operation also.

The maximum percentage of Unmet for 8760 hours of operation is 3.4% amounting to 300 hours. Do we have to take 3.4% of the total fan on hours to calculate maximum unmet hours if the fan on hours is anything other than 8760?

Please help.

Regards,
Rathnashree