In order for a substance to ignite, it must be mixed with air in a certain proportion. This ratio is different from each other according to the properties of flammable materials and is expressed in a range of values. The lower limit to which a flammable substance can explode in the air is called the lower explosion limit (LEL). These values are also used for flammability, but the lower burst limit (LEL) is used more widely because it does not have a very large difference. For example, the lower explosion limit (LEL value) of ammonia is 16, 4 of hydrogen sulfide, 1,3 of gasoline, 7,3 of methyl alcohol and 5 of methane.
Ignition limits for various substances were determined. However, if a gas mixture is found in the environment, the concentration and ignition limits of the components that make up the mixture are calculated.
Our company performs LEL 0-100% LEL measurements within the scope of gas measurements. These studies comply with the relevant legal regulations, standards and test methods published by local and foreign institutions.
To ensure fire and explosion protection in a working environment, flammable vapors in the environment must be below LEL values. Gas measuring detectors used to measure the presence of flammable substances, which are generally found in closed environments, divide the LEL values into fractions (eg 0-100% LEL). The best result is that the LEL value is zero in the measurement devices. However, a warm and hot work permit should be given in this case. The LEL values to be considered are:
- If the level is between 0-5 and the level is allowed, the entry is allowed and sparks can be performed.
- If the level is between 5 and 10, sparks are stopped.
- If the level is between 10-25 and XNUMX-XNUMX, it is considered a situation requiring extraordinary attention and is not allowed.
- If the level is above the 25, there is danger of an explosion, the measure is taken and the work area is abandoned.
