Alarm Parameter Standards for Combined Gas Detectors
The petrochemical industry is inseparable from the gas detector, in which the composite gas detector is one of the important safety procedures for detecting multiple gases in many installations. This is because many industrial production processes will produce many toxic, hazardous or other ozone and other gases, it is necessary to use the composite gas detector for a gas standard monitoring, composite gas detector is a flexible configuration of a single gas or a variety of gas sensors portable gas detection alarms. So do you know the composite gas detector alarm parameters standard is how?
Composite gas detector alarm parameter standards:
Composite gas detector alarm parameter standards should be in line with the corresponding national standard provisions, and are generally to have a first and second alarm value of the relevant requirements. According to the national standard "GBT 50493-2019" for combustible gases and toxic gases detection and alarm design standards for the relevant provisions of the composite gas detector alarm value setting should meet the following conditions:
1, the primary alarm setting value of combustible gas should be less than or equal to 25% LEL.
2, combustible gases should be less than or equal to the second alarm set value of 50% LEL.
3, the first level of toxic gas alarm set value should be less than or equal to 100% OEL, the second level of toxic gas alarm set value should be less than or equal to 200% OEL. when the existing detector's measuring range can not meet the requirements of the measurement, the first level of toxic gas alarm set value shall not exceed 5% IDLH, the second level of toxic gas alarm set value shall not exceed 10% IDLH.
4、The set value of over-oxygen alarm for ambient oxygen should be 23.5%VOL, and the set value of under-oxygen alarm for ambient oxygen should be 19.5%VOL.
5、Line combustible gas measurement of the first level of alarm set value should be 1LEL-m; the second level of alarm set value should be 2LEL-m.
Among them, LEL indicates the lowest explosive lower limit concentration value of combustible gases; OEL is the exposure limit value of occupationally hazardous factors, which means that workers in occupational activities over a long period of time repeatedly exposed to the body does not cause acute or chronic health hazards of the permissible exposure level. Occupational exposure limits for chemical factors can be divided into three categories: time-weighted average permissible concentration PC-TWA, maximum permissible concentration MAC and short-term exposure permissible concentration PC-STEL; IDLH means that the concentration of air pollutants in the hazardous environment reaches a certain dangerous level, such as fatal, permanently damaging to health, or immediately disabling the ability to escape.
