Impact of changes in hydrogen sulfide content standards on 4-in-1 gas detectors
The standard of hydrogen sulfide content of 4-in-1 gas detector is set according to the standard of occupational exposure limit of hydrogen sulfide, which is generally 10mg/m3. Hydrogen sulfide is a kind of poisonous and hazardous gas, and the accumulation of excessively high concentration of hydrogen sulfide in the restricted space will cause serious safety accidents. Therefore, setting a reasonable standard for hydrogen sulfide content is crucial to safeguarding personal safety.
The national standard GB/Z 2.1-2019 Occupational Exposure Limits for Hazardous Factors in Workplaces Part 1: Chemical Hazardous Factors clearly stipulates that the occupational exposure limit for hydrogen sulfide is 10mg/m3. This means that when the concentration of hydrogen sulfide in the ambient air is more than 10mg/m3, it will be hazardous to human beings.
Hydrogen sulfide is one of the gases detected in the 4-in-1 gas detector, along with combustible gases, oxygen and carbon monoxide. Hydrogen sulfide, as a highly toxic gas, is harmful to humans and has a strong irritant effect. Even low concentrations of hydrogen sulfide can be harmful to the eyes, respiratory system and central nervous system, and can even lead to changes in the function of the central nervous system and serious pathological changes.
According to the national standard GB/T 50493-2019 Petrochemical Combustible and Toxic Gas Detection and Alarm Design Standard, the alarm setting value of hydrogen sulfide should be set according to the following standards: the first level low alarm value (AL) should be less than or equal to 10mg/m3, and the second level high alarm value (AH) should be less than or equal to 20mg/m3. This ensures that the alarm is issued in a timely manner when the concentration of hydrogen sulfide exceeds the limit, reminding people to take timely action. This ensures that if the concentration of hydrogen sulfide exceeds the limit value, an alarm will be issued to remind people to take safety measures in time.
In 4-in-1 gas detectors, ppm (parts per million by volume) is usually used as the unit of display for hydrogen sulfide concentration. It is possible to convert mg/m3 to ppm through conversion, according to the conversion formula: mg/m3 concentration = ppm concentration × molecular weight of gas ÷ 22.4, we can get 10mg/m3 is equal to 6.5ppm. Therefore, for hydrogen sulfide, the first level of the low alarm setting value should be set to ≤ 6ppm, the second level of the high alarm setting value should be set to ≤ 12ppm.
In practice, the hydrogen sulfide range of commercially available 4-in-1 gas detectors is usually 0-100 ppm, because in some on-site environments, the concentration of hydrogen sulfide may be much higher than the occupational exposure limit. Particularly in restricted confined spaces where effluent is present, localized concentrations of hydrogen sulfide may be greater than 20 ppm; therefore, a range of 0-100 ppm is preferred to detect hydrogen sulfide to better meet actual needs.
