Regarding the setting of alarm values for toxic gas detectors
Thread Content
The alarm thresholds for our company’s toxic gas detectors are set according to the range of 0–20PPM specified by the design institute: the first-level alarm is set at 7.5PPM, and the second-level alarm at 15PPM. The gas being detected is HCL. Yesterday, a group of experts came to our company for an inspection and said that the thresholds should be set at 5 PPM for the first-level alarm and 10 PPM for the second-level alarm. I was unable to find any basis in the GB50493-2009 standard that requires these values of 5 and 10 to be used. May I ask the experts here how this alarm value should be set? What are the criteria based on?
Using HCl for toxic gas detection?
For toxic gases in 50493, apart from those listed in the appendix, it is necessary to refer to the 2003 version of the list of highly toxic substances; hydrogen chloride is not included in that list, unless you have specific requirements of your own
According to the regulations, HCL does not require testing, and it is not listed in the category of highly toxic substances either
That’s not the key point; the important thing is what determines the set value for the alarm threshold. . . . . .
It is mainly based on the \"Design Code for Detection and Alarm of Flammable and Toxic Gases in Petrochemical Industries\" (GB 50493-2009). The specific provisions are as follows: Below is the full text of the regulation:
This is in accordance with the requirements of the design institute; one can inquire about the rationale behind the experts’ opinions. Experts may have experience, but they don’t necessarily possess design qualifications
According to \"Occupational Exposure Limits for Hazardous Factors in the Workplace – Part 1: Chemical Hazardous Factors\" (GBZ 2.1-2007), the MAC value for hydrogen chloride is 7.5 mg/m³, which is approximately 4.6 ppm
What does the LEL value in 25% LEL mean?
What does IDLH mean, and where can I find it?