[Greenbuilding] infrared thermometer

[nick pine]

"LarenCorie" writes:

>From: John Straube <jfstraube at gmail.com>
>
>> Emissivity of glass is about 0.84, which is not far off a unit
>> with a default of 0.90, like within a degree or two.

>... The sources I have checked, seem to
> all indicate between 0.90 and 0.94
>
> http://www.infrared-thermography.com/material-1.htm
> http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html

If it's 0.92 a la toolbox and 0.92Tg^4 = 0.95Tr^4, using my Raytek Mini-temp
calibrated for 0.95, Tg = (0.95/0.92)^0.25T = 1.008Tr, a Tr = 530 R (70 F)
reading would correspond to Tg = 534 (74 F.) If glass were 0.84, Tr = 530 R
would correspond to Tg = 547 R (87 F.)

Nick