Date
Inquiry

Our client is interested in including a specific roof membrane product in our Specifications. The published data for this product shows that it complies with the Energy Star reflectance component of this credit. However, the published emittance data is relative to ASTM 1371. I contacted the manufacturer and they have sent me an independent test report that they commissioned to test their product under ASTM 408 that reads: "2.0 Test Methods and Procedures Total Normal Infrared reflectance measurements were performed in accordance with ASTM E408-71 (reapproved 2002), Method A. A Gier Dunkle Instruments Infrared Reflectometer Model DB 100 was utilized for the measurements. Inside the detector portion are two semi-cylindrical cavities. One of the cavities is heated by an electrical heater and the other stabilizes at approximately room temperature. Thus, the two cavities are maintained at different temperatures. As the cavities rotate, the sample is alternately irradiated at 13 Hz. A vacuum thermocouple views the sample through an optical system that focuses through slits in the ends of the cavities. The detector receives energy emitted by the sample and energy reflected by the sample. Only the reflected energy contains an alternating component as the sample is alternately irradiated by the hot and cold cavities. An amplifier is synchronized with the cavity rotation to pass only the desired alternating signal, which is then rectified and filtered. The zero and gain are set with standards of known emittance. The calibration is rechecked at several intervals during the measurement." The test results in a Total Normal Emittance of .95 for their white and grey products and .97 for their tan product. The test results were averages of no less than four tests. Is this sufficient information to satisfy the emittance requirement of this credit?

Ruling

Based upon your description, the roofing material manufacturer conducted independent emissivity testing in accordance with ASTM E408-71. The test indicates that the roofing\'s emissivity is 0.95 and therefore meets the credit requirements. The entire testing report is not required for review (only excerpts of the independent testing report that supports the emissivity value, the testing methods and the testing specimen would need to be included in the LEED submission).

Internationally Applicable
Off
Campus Applicable
Off