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Carbon
Monoxide (CO) Contamination:
Carbon monoxide (a colourless, odourless gas) is the most toxic contaminant in compressed air.
Headaches, dizziness, unconsciousness or death can occur from exposure to
elevated CO levels. It enters
the breathing air system through the air intake, or is produced by overheating
of piston type compressors. The air intake must be placed away from engine
exhaust or other sources of carbon monoxide. High pressure compressors can be equipped with a catalyst which converts CO into much less toxic
carbon dioxide. Table 1 of CAN3-Z180.1-00 lists a 5 ppm
maximum CO content. Occupational Health OEL value is 25 ppm therefore a
1/10 threshold valve is 2.5 ppm. This 2.5 ppm value is the correct maximum for
carbon monoxide. If a properly functioning, efficient and contaminant free
compressor is
in use, CO levels will be less than 1 ppm.
Detectable CO levels above 1 ppm
are "abnormal" & require further investigation.
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