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GAS DETECTION 101
THREE TYPICAL GAS HAZARDS TO BE AWARE OF
• Where Oxygen levels are too rich, environments have the potential to become an
explosive environment
• Where Oxygen levels are too low, people within the environment can succumb to
asphyxiation
•
Gases such as Oxygen, Carbon Dioxide, Nitrogen, Helium, Argon
ASPHYXIANT
OR OXYGEN
DEPLETING
FLAMMABLE
• Having the right combination of an ignition source, oxygen, and fuel in a gas or vapor
form provides for the necessary means to create a fire or explosion
• The minimum concentration of combustible gas or vapor necessary to support its
combustion in air is defined as the Lower Explosive Limit (LEL). Below this level, the gas
mixture is too “lean” to burn
• The maximum concentration of a gas or vapor that will burn in the air is defined as the
Upper Explosive Limit (UEL). Above this level, the mixture is too “rich” to burn
• The range between the LEL and UEL is known as the flammable range for that gas or vapor
• Gases such as Methane, Hydrogen, Propane
TOXIC
• Some gases are poisonous and are dangerous to life at very low levels. Some toxic
gases have distinct odors (H
2
S, NH
3
) and others have no odors at all (CO)
• Very low levels inhaled, ingested, or absorbed through the skin pose adverse effects
from exposure
• Gases such as Carbon Monoxide, Nitrogen Dioxide, Ammonia, Hydrogen Sulfide
