TOPIC: IR Emissivity

I was watching a chat regarding emissivity.  John, I think you had a question as to what to use.  My camera is defaulted to .95 and I typically leave it there.  I'm attaching Fluke's emissivity values with hope it helps some folks out. 

Greg

Yes you bring up the question I was asking.  0.95 is the emissivity the unit is calibrated at.  And for the most part is its wouldn't hurt to take your reading at that setting (its the easiest).  But you have to ask yourself, how good are those readings? Typically the more heat absorbent the item you are shooting is, the higher you want your emissivity setting and vice verse.

So when shooting a house with many different materials what would you set your unit too?  And how accurate are the scans if you stay at 0.95?

There's qualitative and quantitative images.  Most images we'd take as a home inspector are qualitative.  We're looking for thermal differences showing anomalies.  We need to be aware of emissivity and reflections when we take these images but we don't need to make camera adjustments because we're not concerned with precise temperatures.  Quantitative images require more care because exact measurements are taken.  Emissivity, reflectivity, background objects and atmospheric conditions all affect the image temperature readings. We would need to make changes in the camera if we were taking quantitative images. us.fluke.com/usen/support/software/OnlineTools.htm?trck=titools

Hope this helps.

Greg