BREATHING AIR ANALYSIS: A Safety Requirement

Why should you spend money having your air analyzed? Afterall, you know that you have a good QA program, and you change your filters on a scheduled basis; right? And, you know what you are doing, so you should just save that money. Right? WRONG!

Things can go wrong if all you do is rely on changing filters. Organizations not performing scheduled air analyses, honestly believe that their QA program can discover as well as prevent problems. Although the great majority of air systems we test consistently produce good clean air, here are some documented case histories which are a reminder of things which go unobserved if all you do is change air filters and check the CO level.

1. A group of divers became sick despite no odor, no evidence of oil, and normal
readings on the system’s CO detector. Changing filters did not alter the problem. Laboratory analysis revealed methane from a leaky gas pipe. In another case with similar symptoms, analysis identified paint solvents.

2. Hopcalite is a catalyst (CuO+MnO) which destroys CO by oxidizing it to CO2 but not if the air is wet. The catalyst becomes hot as it reacts with moist air. Molecular Sieves also get very hot if the incoming air is very wet. In this case, the heat of the reaction with moisture caused the plastic filter housing to melt, and spew into the piping.

3. A training dive was cancelled when the entire group became sick. Another diver ignored the odor, and surfaced experiencing blurred vision, muscle impairment, and convulsions; he had to be hospitalized and required oxygen therapy.

4. Our routine sampling program at the USN Dive School discovered oil mist escaping the filters. Our early warning allowed the compressor to be repaired before harm came to any diver.

5. In separate incidents, desiccant disintegration, charcoal dusting, and cylinder destruction were not visible during charging, but were discovered during our sampling and analyses. The pile of filters all came from air systems thought to be clean and safe to use.

OSHA REQUIREMENTS 29 CFR 1910.430(b)(4)
The law says that if you supply breathing air to an employee, you must have a QA program that includes laboratory analysis.
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