This CIR is to appeal an earlier ruling (6/13/02) that states that "...the LEED language requires emissivity of \'\'AT LEAST\'\' 0.9; therefore rounding up from a lower value is not allowed." Strict conformance to that ruling leaves 8 options in the 11 pages of CRRC product listings, 2 choices of Modified Bitumen (the roof specified for this particular project), only 1 of which also meets the Energy Star requirement. This is a public bid project (city fire station) being paid for with bond money. In order to benefit from a competitive bid, we need to provide at least three manufacturers. While I agree with the goal of pushing the market to make better products, the absolute stringency of this requirement ("at least 0.9") leaves me accepting bids that will not meet the intent of this point. I would rather be able to accept bids that are at least close (.85-.89) as they are certainly better than having a poor emissivity. Please reconsider this position and advise. Thank you.
It is not acceptable to round up the emissivity value in order to achieve this credit under LEED v2.0 or 2.1.. The challenges associated with finding products that meet both the reflectance and emissivity criteria are being considered by the TAG. Of possible interest to your project is that the USGBC has previously ruled that it is acceptable to take a weighted average of emissivity for single or multiple roofing products by area (effectively allowing less emissive products). The methodology for the calculation is the same as that described for non-roof surfaces in a CIR under SSc7.1 dated 12/5/2001. Applicable internationally.