Leakage Rate

See page 215 of the LEED Reference Guide for the calculations definitions and minimum value for the annual leakage rate. My understanding was that, at a minimum, the annual leakage rate of not less than 0.5% must be used.

LEED ONLINE CALCULATIONS ISSUE?: I am confused with the formulas given in the reference guide. The 3 examples given takes the sum of the (LCGWP + LCODP * 10^5) * N * Qunit and divides it by the Qtotal to get the value of less than 100. But in the formula listed next to Avg. Reg. Atmos. Impact in the 3 charts it ignores the N-value. My project has multiple pieces of equipment so I have to take an average the formula on page 222 confuses me as the Qunit value differs by unit, I assumed the average of the total would have to be less than 100. Also the LEED Online tool does not provide an average score it only sums up the totals of 3 columns. I dont see an area with a final avg. refrig. atmos. impact score. Could someone help me out with explaining what I am missing?

Hi Paul,The formulas in the reference guide on page 222, are a bit confusing, but they do not ignore the n-value. The n-value is synonymous with the column titled “units” in the first example on page 222. So the n-value (or number of units) is accounted for in both the last column where each type of HVAC equipment is calculated using “n” in the formula; and in the first and second columns where the Qtotal is calculated. This means that both the subtotal and the Qtotal take n-value (or number of units) into consideration. Then you divide the subtotal by the Qtotal to get the Average Refrig. Atmos. Impact Score. Thus n-value is represented as the Qtotal and it’s also included in the calculations to arrive at the numerator in the equation for the Average Refrig. Atmos. Impact Score.Regarding LEED Online, the second to last column labeled “Refrigerant Impact per ton” shows the Average Refrig. Atmos. Impact Score, for all of the equipment listed, taking n-value into consideration. The final column labeled “Refrigerant Impact Total” is comparable to the subtotal listed in the example charts in the reference guide.