At present, in the petrochemical industry, metal smelting, fire fighting, electric power, gas station, mine, kitchen, pharmaceutical and other industries that exist or use combustible gas, the use of combustible gas alarm is indispensable. It is the 1 safety instrument mainly used to detect the concentration value of flammable and explosive gas in the ambient air. When the leakage concentration of combustible gas exceeds the standard, the combustible gas alarm can quickly respond and send an alarm signal to remind the field staff to reduce the occurrence of dangerous accidents. Therefore, in the process of using, we often need to set the measurement range and alarm value of the combustible gas alarm. Then you know combustible gas alarm ? The following is a brief introduction by yi yun Tian:

Combustible Gas Alarm Measurement Range and Alarm Value setting method:

1. according to article 5.5" measurement range and alarm value setting "of GBT 50493-2019 petrochemical combustible gas and toxic gas detection and alarm design standard:

1. The first level alarm setting for combustible gas shall be less than or equal to 25% LEL.

2. The secondary alarm setting for combustible gas shall be less than or equal to 50% LEL.

3. The primary alarm setting value for linear combustible gas measurement shall be 1LEL · m; the secondary alarm setting value shall be 2LEL · m.

where LEL is the English lower explosion The abbreviation of limit refers to the lowest concentration at which a mixture of combustible vapor, gas or dust and air can explode when exposed to an ignition source (the concentration of combustible vapor and gas, calculated by volume ratio).

The concentration of combustible gas is too low or too high. It is not dangerous. It only burns or explodes when it is mixed with air to form a mixture or more precisely when it meets a certain proportion of oxygen to form a mixture. Due to the higher proportion of air, when monitoring the leakage concentration of combustible gas, it is necessary to monitor the volume concentration value from very low concentration to the lowest explosion limit, that is, the measurement range is 0~100 LEL.

2. Under normal circumstances, the alarm value of the combustible gas alarm is set:

The lower limit defaults: 25% LEL(5% LEL ~ 40% LEL adjustable)

High limit defaults: 50% LEL (adjustable from 10% LEL to 100 LEL)

is set as follows:

combustible gas alarm has a measuring range of 0-100% LEL, and is generally set between 15% and LEL-25 LEL according to national regulations.When its gas alarm has two alarm setting values of low limit and high limit, its low limit alarm setting value shall be in the range of 1% lel ~ 25% lel, and its high limit alarm setting value shall be 50% lel. Detectors with only one alarm setting shall have an alarm setting within the range of 1% lel to 25% lel.

Therefore, the alarm value of combustible gas alarm specified in the national specification is the upper limit, as long as it is not greater than this upper limit, it is within a reasonable range. Of course, in the actual installation process, we should proceed from the professional practical point of view, the alarm value of the combustible gas alarm should not be too low, too low prone to false positives, because too low may conflict with the detection error.

To sum up, it is the measurement range and alarm value setting method of combustible gas alarm. According to the current national regulations, the low report of combustible gas alarm is generally set at 25% LEL and the high report is set at 50% LEL.If you have any questions about the alarm value setting of combustible gas alarm, please call Yiyuntian and we will serve you wholeheartedly!