User guide

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MRK-D-0022 V3.1 Aeroqual Series 200, 300 & 500 User Guide
The United States Department of Labour
http://www.osha.gov/SLTC/compressedgasequipment/index.html
The following information is a guide for what to consider when handling compressed gas but Aeroqual
recommends operators adhere to their local regulations regarding compressed gas handling.
6.5.1. High pressure leak or failure of pressure regulator
Many calibration gases are held in cylinders at high pressure in excess of 1000 Psi. Incorrectly fitting
the pressure regulator, using a regulator which is faulty or knocking the cylinder over while the
regulator is attached can cause physical harm from high speed projectiles resulting from a high
pressure leak from or failure of the regulator.
 It is important to always fit a high quality undamaged pressure regulator to the gas cylinder
and that the regulator type is suitable for the cylinder you are attaching it to.
 Always use protective eyewear (safety glasses) when working with compressed gas.
 Always point the cylinder and regulator away from yourself and others when attaching or
removing the pressure regulator.
 Always secure the cylinder to prevent it from being knocked over while the regulator is
attached.
6.5.2. Flammability of combustible gases
Calibration gas can be stored in cylinders at high concentrations and can this can present a hazard if
those gases are combustible. The lower explosive limit (LEL) is the lowest concentration of gas at
which combustion will be sustained in air if an ignition source (spark or flame) is present. The LELs for
the gases used for calibrating Aeroqual sensor heads are all significantly above the calibration span
points so this risk is low. It is important however that the LEL be known for the gas being employed
and that suitable precautions be taken to further minimize the risk from explosive combustion such as
performing the calibration in a fume hood. The table below lists the LELs for the gases used to
calibrate Aeroqual’s sensor heads.
6.5.3. Toxicity
While most of the recommend span points fall below the Immediately Dangerous to Life or Health
(IDLH) limits published by the National Institute for Occupational Health and Safety (NIOSH), some
span points are above these limits and therefore it is crucial that rigorous health and safety
procedures be followed during calibration to avoid exposure to the calibration gas.
The table below lists the IDLH concentration limits as well as concentration limits for longer exposure
times. The LDLH limits are known for most of the gases of concern, however there are some gases
for which data are not available. In these cases gases should be considered as being toxic and