Safety Limitations And Precautions - MSA SIRIUS Manual De Instrucciones

1 Instrument Safety and Certifications

1.1 Safety Limitations and Precautions

It is very important to have an understanding of PID basics when changing your
PID settings. Failure to properly identify the VOC gas being measured and/or
failure to select the correct Response Factor alarm values (exposure, STEL, TWA)
that match your desired Response Factor and/or the correct bulb, will result in
erroneous readings.
Carefully review the following safety limitations and precautions before placing this
instrument in service:
The SIRIUS Multigas Detector is designed to:
• Detect gases and vapours in air only
• Detect only specified toxic gases for which a sensor is installed.
Perform the following check before each day's use to verify proper instrument operation:
• Calibration check (see 3.12 Calibration Check). Adjust calibration if the readings are
not within the specified limits.
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 "4.4" (in
CH mode) indicates the atmosphere is at 100% LEL or 4.4% CH
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ly, 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 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 vapours from liquids with a high flash point (above 38 °C, 100 °F) as this may
result in erroneously low readings.
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(by volume), respective-
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