MSA Sirius Operating Manual page 11

• Check calibration more frequently if the unit is subjected to
physical shock or high levels of contaminants. Also, check
calibration more frequently if the tested atmosphere contains the
following materials, which may desensitize the combustible gas
sensor and/or VOC sensor (PID) and reduce its readings:
• Organic silicones
• Silicates
• Lead-containing compounds
• Hydrogen sulfide exposures over 200 ppm or exposures
over 50 ppm for one minute.
• The minimum concentration of a combustible gas in air that can
ignite is defined as the Lower Explosive Limit (LEL). A combustible
gas reading of "100" (in LEL mode) or "5.00" (in CH 4 mode)
indicates the atmosphere is at 100% LEL or 5.00% CH 4 (by
volume), respectively, and an explosion hazard exists. In such
cases, the instrument LockAlarm feature activates. Move away
from contaminated area immediately.
• Do not use the Sirius Multigas Detector to test for combustible or
toxic gases in the following atmospheres as this may result in
erroneous readings:
• Oxygen-deficient or oxygen-rich (greater than 21% by
volume) atmospheres
• Reducing atmospheres
• Furnace stacks
• Inert environments
• Atmospheres containing combustible airborne mists/dusts
• Ambient pressures other than one atmosphere.
• Do not use the Sirius Multigas Detector to test for combustible
gases in atmospheres containing vapors from liquids with a high
flash point (above 38
low readings.
• Allow sufficient time for unit to display accurate reading. Response
times vary based on the type of sensor being utilized (see Chapter
7, Performance Specifications ).
• All instrument readings and information must be interpreted by
someone trained and qualified in interpreting instrument readings
in relation to the specific environment, industrial practice and
exposure limitations.
• Replace alkaline batteries in non-hazardous areas only. Use only
batteries listed on the approval label.
° C, 100°F) as this may result in erroneously
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