Last week I talked about some of the potential issues for Emergency Responders re build up on the Fresnel lens system in an infrared temperature gun. Smoke & ash from fires are one set of issues, and chemical extinguishing agents are another. Chemical vapor residues from a chemical leak (say methyl bromide, for example) can cause problems, too. There's a fourth category for all detection & measurement equipment, but I'll address that next posting.
But how often should you clean a top notch temperature gun (say our Top Temp Gun or the Flash Point Temp Gun)? Here's the answer from our techs:
If the following procedure is not followed, there will be an error of accuracy from 10 degrees F to 40 degrees F minimum for the readings.
1] EVERY unit we supply should be cleaned weekly to eliminate dust, girt and grime that will build up on the lens system.
1a. This can be done using a soft cloth or cotton swab with alcohol.
2] The advantage of the IR100_2 and the TN425 is the low temperature range of -76 to check accuracy of the unit.
2a. Simply fill a vessel with ice and water : check the temperature: reading should be between 27F to 35 F.
2b. There should be only a drift from 32F .. 27 low and 35 high
These readings should be within our stated accuracy.
3] Finally, let's go beyond the lens issue...
Sometimes dust and particulates from emergency response scenarios can be blown beyond the outer Fresnel lens, and even beyond the hard glass lens and right into the microprocessor.
THIS event will cause an additional error in accuracy of 10 -20 degrees of the reading.
There is NO WAY to take the unit apart and blow out the dust without destroying the guts of the unit.
If the unit is too far out of whack as determined by ice water test... then we will need to replace it ASAP.
Remember that high end infrared temperature guns are precision instruments. Treat them like they are and they can help keep you and your team safe.