Message Board Thread - "wind effect on infrared reading.."

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wind effect on infrared reading.. thermoimagen 3/10/2004
i found this information, anyone can update it?..

Compensating for wind effects: source Agema Infrared Systems:

Wind Speed (m/s)........Correction Factor
...1 or less ............... 1.0
....2....................... 1.36
....3....................... 1.64
....4....................... 1.86
....5....................... 2.06
....6....................... 2.23
....7....................... 2.40
....8....................... 2.50
....9 or more Measurements nor recomended

1 m/s = 2 knots = 2.2369 mph

source:
Practical applications of Infrared thermal Sensing
and imaging equipment. Second edition, H. kaplan, page 98.


regards
 
Re:wind effect on infrared reading.. Doctir bob 3/11/2004
We have done experiments in this area and have published papers on the topic:

Madding Robert P. and Lyon Bernard L; “Wind effects of electrical hot spots—some experimental IR data”; Thermosense XXII; Proc. SPIE; Vol. 4020, April, 2000; pp 80-84.

You can get a copy of this through the www.spie.org website. I believe they also sell a 2 CD set that has the first 25 years of Thermosense Proceedings, a good value for any thermographer.

The data you show are from an old experiment and are not valid for today's world. One of the problems with wind speed correction is the factor depends on the amount of power being dissipated by the thermal anomaly. So, to truly correct for wind speed, you need to know the power generating the heat. But if you know that, you already have the answer. Our published results show a range of values depending on the power being dissipated. We recommend using the curves to estimate a range of temperature rise correction.

Wind speed is extremely influential on thermal measurements. A 3 mph wind can cut the temperature rise in half. Winds of 15 to 20 mph can "wipe out" small temperature rises.
 
Re:wind effect on infrared reading.. Doctir bob 3/11/2004
One more thought: The old correction corrects to 1 kt, or 2.2 mph, not to 0 mph. As the effect of the wind is quite strong from 0 mph to 3 mph, this is one of the primary problems with this approach. It may have some validity for areas where there is always some wind, given the caveat of power dissipation variability.
 


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