Question 1

Will high humidity affect my PID's readings?

Accepted Answer

Yes, high humidity can affect readings. It can cause a phenomenon called "quenching," where the water vapor absorbs some of the UV energy, leading to a reading that is slightly lower than the actual concentration. In extreme cases, condensation can form on the sensor, causing erratic readings. Many modern PIDs have features to help compensate for humidity.

Question 2

Can a PID be used for confined space entry?

Accepted Answer

A PID can be a useful supplementary tool for confined space entry, but it should not be the primary instrument. Standard confined space monitors test for oxygen levels (deficiency or enrichment), flammable gases (as a percentage of the LEL), and specific toxic gases like carbon monoxide and hydrogen sulfide. A PID can be used afterward to screen for other toxic VOCs that these sensors would not detect.

Question 3

Is a PID an intrinsically safe device?

Accepted Answer

Many PIDs designed for use in hazardous locations are certified as "Intrinsically Safe" (IS). This means their electrical design prevents them from producing a spark that could ignite flammable gases or dust. It is vital to check that the specific model of PID you are using carries the proper IS rating for the environment in which you plan to use it.

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