emissivity offset by humidity

[ShilohHawk]

I am trying to get some accurate reading for air temperature... I am able to get the air temperature by using a probe, but I would like to have the option of using a temp gun...
The humidity is between 90-95% at all times... I have currently tried using white bond paper, but the paper does not stay accurate very long due to the high humidity because it’s absorbing the water... I have also tried using Scotch super 33 on a few different surfaces (foil, paper thin plastic, paper) and I seem to be battling the same issue... The air temps should be about 30.1 Celsius however after about 3-4 hours of being exposed to the humidity the reading will bounce all the way up to 31.5 (or round about)… Before the 3-4 window I am able to get accurate readings… The probes are not showing a bounce…

I am making an 8” square with the tape…

Is there a humidity equation out there somewhere? Any suggestions?

Thanks
Shiloh

 

[IRJohn]

These minor variations in humidity at these distances should not have much of an impact on the measurement. Typically the methodology you are using, taking a temperature of paper, is a good one.

I would suggest you are probably within the limits of accuracy and repeatability for the instrument you are using, but you may want to check the specifications.

If I can be of further assistance, please feel free to contact me.
John Snell
Snell Infrared

http://www.snellinfrared.com

 

[ShilohHawk]

Do you have any suggestions on how to keep my measurement accurate for longer then 3-4 hours... It would be nice to have something in there at all times to take a reading off of...
The reason I am getting a higher reading after 3-4 hours is because the humidity has saturated the paper/tape... I am suprised that with no condensation in the enclosure that the tape is affected... The setup is a Forma incubator with a sterilite tub inside the incubator... The tub inside has approx 2" of water in it and I an trying to take the air temperature a few inches over the water... As far as I can see the temp inside the tub is .2 higher then the temperature in the incubator, but like I said I am hoping to have a method to check temps at any time, especially in the early morning...

thanks
Shiloh

 

[IRstuff]

Have you tried something like just a piece of metal sprayed with Crylon 1802 Ultra-flat Black? You really need to use something that will not abosrb moisture.

Another thing that might be worth trying is to maintain an airflow across the target, such as with a small muffin fan, as this should evaporate the condensation on a continuous basis.

TTFN

FAQ731-376