Combustible Gases
Combustible gases are gases that can ignite and burn when mixed with air (or oxygen) at certain concentrations. When these gases are present within a specific range—between their Lower Explosive Limit (LEL) and Upper Explosive Limit (UEL)—they can form a flammable or explosive atmosphere. If an ignition source such as a spark, flame, or hot surface is introduced, this mixture can lead to a fire or explosion. These gases are often colorless and odorless, making them difficult to detect without instrumentation. Because even relatively low concentrations can become dangerous, combustible gases present a significant risk in industrial, commercial, and confined environments. For this reason, continuous monitoring using gas detection systems is essential to identify leaks early and keep concentrations well below explosive levels. CET offers catalytic bead, infrared, and semiconductor sensors for combustible gas detection in utility rooms, industrial facilities, and commercial buildings.
Why Detection Matters
Gas detection is critical for combustible gases because even small amounts can form an ignitable mixture with air and lead to fires or explosions if an ignition source is present. These risks are defined by the Lower Explosive Limit (LEL) which is the minimum concentration at which a gas can ignite; meaning dangerous conditions can develop at relatively low levels. Continuous gas detection monitors %LEL and provides early warning well before ignition thresholds are reached, allowing actions like ventilation, shutdown, or evacuation to prevent catastrophic events. To manage these hazards, several key standards apply. OSHA regulations require monitoring of flammable atmospheres in workplaces such as occupied areas, confined spaces and hazardous operations, often using LEL thresholds (e.g., 10% LEL as a danger point). Fire and building codes, including NFPA 72, govern how gas detection is integrated with alarm systems and require listed detection equipment in certain applications. At the equipment level, international standards such as IEC/CSA/UL 60079 29 1 and 60079 29 0 define performance, testing, and reliability requirements for flammable gas detectors used in hazardous environments. Together, these standards ensure gas detection systems are accurate, properly installed, and capable of preventing fires and explosions in environments where combustible gases are present.
Common Hazards:
Gases
Explore combustible gases
Methane (CH₄)
Colorless, odorless, highly flammable gas
Propane (C₃H₈)
Colorless, odorless gas commonly used as fuel
Hydrogen (H₂)
Lightest element, colorless, highly flammable
Ethanol (C₂H₆O or C₂H₅OH)
A volatile, flammable alcohol used in the beverage, fuel blending and pharmaceutical industry
Natural Gas (CH₄+)
Fossil fuel primarily composed of methane
Related Applications
Applications that monitor combustible gases