INTERSPIRO QS II BASIC Manuel De L'utilisateur page 9

The breathing air with which the cylinders are charged must meet the requirements
according to EN 12021, being free from oil, toxic substances and having low humidity.
The duration of a compressed air breathing apparatus depends on the volume of air
in the compressed air cylinder(s) and the air consumption, which is specific to the
wearer and affected by the work load. When taking air from the extra air connection,
which some models are equipped with, the air consumption increases and the
duration of the apparatus decreases.
When operating with two separate independently valved cylinders both cylinders
must be charged with similar working pressures. Always open both cylinder valves
when pressurizing the breathing apparatus and ensure that both cylinder valves are
kept open during the use of the apparatus.
If the self contained breathing apparatus is to be used in conjunction with other
personal protective equipment it is important to ensure that the additional personal
protective equipment is compatible with the breathing apparatus and does not impair
the full protection of the respiratory protective device.
Examples of dangers which may require the use of additional personal protective
equipment:
-Liquids, steam or gases which can damage the skin.
-Pollutants absorptive by skin
-Thermal radiation
-Mechanical effects
-Explosive environments.
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