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How Do LEL Detectors Work?

Combustible gas and solvents that create explosive vapor in air when spilled, or leak into an area, have a Lower Flammable Limit found on a specific Material Safety Data Sheet materials (MSDS). LFL is the same as LEL. Combustible Gases and Solvents also have an Upper Flammable Limit (UFL), which is the same as with UEL, or Upper Explosive Limit. An LEL Detector simply detects, indicates and alarms for levels between 0-100% LEL of materials it is calibrated to monitor and detect.

Using methane in air as an example, the LEL of methane is 5% by volume. So an LEL Detector or an LEL analyzer, working as part of a complete LEL Gas Detection System, that’s calibrated to detect methane in air in a range of 0-100% LEL Methane will detect the presence of methane in air between 0-100% LEL, or 0-5% by volume. An LEL Meter in a fixed gas detection system calibrated for 0-100% LEL methane when reading 50% LEL methane will read the equivalent of 2.5% Methane by volume in air.

Because LEL analyzers are detecting combustible gas or solvent vapor in the LEL range above, the LEL Detector is functioning in a safe range, before the LEL level reaches 100% LEL, or the minimum level needed to support ignition or combustion. An LEL Detector is an essential component of a fixed gas detection safety instrument for LEL safety and so monitors, indicates and alarms when levels of LEL exceed 0% to indicate the presence of combustible gas or solvent vapor. This is well before a combustible fuel/air mixture exists near the LEL analyzer.

Generally, the dangerous areas where these combustible materials remain or get used are regulated by local, state and federal entities, and designated as hazardous locations. LEL Detectors and the fixed gas detection system that they work within are also classified for use in the hazardous locations where these materials are kept or interacted with, to maintain LEL safety.

It is also important to understand the differences and apply the correct LEL Meter sensor technology to the application for LEL safety. Catalytic Bead sensors and Infrared sensors are used in LEL Detection, and each has advantages and disadvantages that need to be fully understood before selecting the proper technology to be used in a fixed gas detection system that uses an LEL analyzer.

Contact GDS Corp. Today

If you have any questions about LEL safety, the LEL detector working principle or the LEL analyzer wiki, feel free to give us a call, using one of the many provided phone numbers. Our application engineers look forward to hearing from you!

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