What Does the Measurement Range of 0-100% LEL for Combustible Gas Detectors Mean?
LEL "refers to the lower explosive limit. The low concentration of combustible gas that explodes when exposed to a spark in air is called the lower explosive limit, abbreviated as% LEL. English: Lower Explosion Limited.
The high concentration of combustible gases that can explode when exposed to a spark in the air is called the upper explosive limit, abbreviated as% UEL. English: Upper Explosion Limited.
So what is the lower explosive limit?
The concentration of flammable gases is too low or too high, and it is not dangerous. It only burns or explodes when it mixes with air to form a mixture, or more precisely, when it encounters oxygen to form a certain proportion of the mixture. Combustion is a violent oxidation reaction accompanied by luminescence and heating, which must have three elements: a. Combustible material (gas); b, Combustion aid (oxygen); c, Ignition source (temperature). The combustion of combustible gas can be divided into two categories. One is diffusion combustion, which refers to the mixing and combustion of volatile or leaked combustible gas from equipment when it encounters an ignition source. Another type of combustion is the combustion of combustible gas mixed with air, which is intense and fast, usually producing huge pressure and sound, also known as explosion. There is no strict distinction between combustion and explosion.
Authoritative departments and experts have conducted combustion and explosion analysis on the currently discovered combustible gases, and formulated explosive limits for combustible gases, which are divided into upper explosive limit (UEL) and lower explosive limit (LEL)? )Below the lower explosive limit, the combustible gas content in the mixture is insufficient to cause combustion or explosion, and above the upper limit, the oxygen content in the mixture is insufficient to cause combustion or explosion. In addition, the combustion and explosion of combustible gases are also related to factors such as gas pressure, temperature, ignition energy, etc. The explosion limit is generally expressed in terms of volume percentage concentration.
Explosion limit refers to the general term for the lower and upper explosive limits. The concentration of combustible gases in the air will only explode when it is between the lower and upper explosive limits. No explosion will occur below the lower explosive limit or above the upper explosive limit. Therefore, when conducting explosion measurements, the alarm concentration is generally set below 25% LEL of the lower explosive limit.
