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By Gas
      - Carbon Monoxide
      - Ammonia
      - Nitrogen Dioxide
      - Hydrogen Sulfide
      - Sulfur Dioxide
      - Combustibles
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Gas Family: Combustible Gases

We offer gas detection and gas sensors for a wide range of hydrocarbons and inorganic compounds for which the primary hazard is flammability/combustibility.

Product Uses/Sources/Applications

  • Gas sensors and gas detection for fuel used in vehicles, heating units, and industrial processes (methane, propane, hydrogen, gasoline, etc.)
  • A byproduct of processes involving the breakdown of organic matter (waste water treatment  , pulp & paper , etc.)
  • As a naturally occurring compound within the earth’s crust (methane).  It is extremely hazardous and gas detection and sensors can be used in underground mining  applications, especially in, but not limited to coal facilities, as it may be present in almost any mining application
  • In oil and gas drilling, production and transportation
  • Wherever multiple batteries are being charged  (underground telephone switching systems, large UPS, warehouses with electric forklifts, golf cart charging areas, etc.), hydrogen is produced



Some combustible gases such as carbon monoxide, ammonia, etc., are both highly toxic and combustible.  Strategies for monitoring for such gases should be determined on an application by application basis.


Flammability is measured in Lower Explosive Limit (LEL) and Upper Explosive Limit (UEL).  The LEL represents the minimum amount of gas (by volume in air) which is required to promote combustion.  See chart below:

Combustible Gas

LEL (%Vol of Gas in Air)
Relative Density (Air = 1)
Acetone 2.50 2.0
Acetylene 2.50 0.9
Ammonia 15.00 0.6
Butane 1.90 2.0
Carbon Monoxide 12.50 1.0
Ethyl Acetate 2.00 3.0
Ethyl Alcohol 3.30 1.6
Gasoline 1.40 3-4
Heptane 1.05 3.5
Hexane 1.10 3.0
Hydrogen 4.00 0.1
Isopropyl Alcohol 2.00 2.1
Methyl Ethyl Ketone (MEK) 1.40 2.5
Methane 5.00 0.6
Methyl Alcohol 6.00 1.1
Octane 1.00 3.9
Pentane 1.50 2.5
Propane 2.10 1.6
Toluene 1.10 3.1

Armstrong Monitoring Recommends

Sensor Type: Catalytic Pellistor or Infrared
Standard Range: 0-100% LEL
Standard Trip Points: 20% LEL, 40% LEL
Recommended Sensor Mounting Height: Determined by relative density of gas


Armstrong Monitoring
215 Colonnade Road South
Ottawa, Ontario
K2E 7K3

Toll Free: 800.465.5777

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