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Air
Composition:
Clean, Natural Air is an odourless, colourless
gas mixture. Excluding water vapour levels (which vary greatly), three major
components make up about 99.97% of dry air: Nitrogen
78.09% / Oxygen 20.95% / Argon 0.93%
An important minor component of natural air
is Carbon Dioxide (300 ppm). Other trace gases include: Methane (2 ppm), Hydrogen, Nitrous oxide, Ozone
and some noble gases all less than 1 ppm.
Reconstituted or Synthetic Air is also used in SCBA applications. This
type of air is produced by blending (liquid or gaseous) nitrogen and oxygen
in the proper proportions.
The dangers associated with breathing contaminated
air are critical when using SCBA tanks
in emergency situations.
To insure SCBA air quality,
CAN3-Z180.1-00 (
Section 15.2 ) requires that air produced by the breathing air system
shall be submitted for purity analysis at least once every 6 months.
Additional
analyses shall be required following major overhaul modifications or
extensive repairs to the breathing air system. Many companies have
adopted a 3 month air testing schedule and maintenace program.
ppm = parts per million
SCBA = Self Contained Breathing Apparatus
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