In the picture on the "Bird's Eye View" page, there is a picture of an infrared thermometer. This would take the temperature of an object. However, in order to comply with this credit, it is my understanding that we must be in compliance with the testing proceedures outlined in ASHRAE 55 and therefore use a black globe thermometer. Has anyone had success with this credit using just a simple radiant thermometer? I don't want to buy something I don't need, but the attached spreadsheet in the documentation toolkit would suggest a black globe thermometer is appropriate as well.
Further, ASHRAE 55 requires that we do the testing on a Design temperature day. Does anyone know if GBCI has been strict enforcing this requirement? Hitting a design day is somewhat difficult to schedule! The weather won't share its calendar!
Thanks!
Jason Franken
Sustainability ProfessionalLEEDuser Expert
608 thumbs up
November 2, 2011 - 11:15 am
Sonrisa, I believe that either device (an infrared thermometer or a black globe thermometer) would be acceptable to take periodic radiant temperature readings. I could be wrong, but I don't think ASHRAE 55 excludes the use of infrared thermometers. Honestly, when LEED User was being built, we may have just had a better photo of an infrared thermometer to put on this page.
As far as the testing schedule, you don't have to hit on a perfect design day, but GBCI will want to see that you are being thoughtfull about scheduling the testing in an appropriate time of the year.
Jeremy Poling
Senior ConsultantGoby
39 thumbs up
November 28, 2011 - 1:44 pm
ASHRAE 55 does not require a specific device, but requires you to measure mean radiant temperature (MRT).
Neither globe thermometers nor infrared thermometers measure MRT, but both produce results that can be converted to mean radiant temperature. The two technologies would just require different equations to convert the measurements.
Globe thermometers are more common since they only require one measurement to determine mean radiant temperature. Their measurement can be converted to MRT via Equation 11 on page 14.29 of ASHRAE Fundamentals 2005.
Infrared thermometers will require at least six measurements for each point (top, bottom, four sides) which can be converted to MRT via Equation 50 on page 8.10 of ASHRAE Fundamentals 2005.