<html><body><div style="color:#000; background-color:#fff; font-family:arial, helvetica, sans-serif;font-size:12pt"><div>Dear All,</div><div><br></div><div>The following is the procedure i use to calculate unmet hours:</div><div><br></div><div>1)<span class="tab"> </span>Percentage of Plant and system unmet is got from BEPU report. </div><div><br></div><div>2)<span class="tab"> </span>The number of hours fan is on is got from SS-E report. </div><div><br></div><div>3)<span class="tab"> </span>Percentage of system unmet(BEPU) multiplied by number of fan on hours(SS-E) gives the Unmet hours. <br></div><div><br></div><div>4)<span class="tab"> </span>Plant and system unmet together should not exceed 300 hours.</div><div><br></div><div>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.</div><div><br></div><div>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?</div><div><br></div><div>Please help.</div><div><br></div><div>Regards,</div><div>Rathnashree</div></div></body></html>