The issue of toxic gases
Thread Content
In the production facility, a toxic gas alarm (benzene) is installed. What are the first-level and second-level alarm thresholds for benzene in mg/m3?
The primary alarm limit (STEL) for benzene is 5 mg/m3; that is, exposure over a short period of time (15 minutes) should not exceed 5 mg/m3. The secondary alarm limit (TWA) is 1.6 mg/m3, meaning the average exposure over an 8-hour period should not exceed 1.6 mg/m3. However, the specific alarm values need to be determined based on the specific conditions of your production equipment and the health status of the personnel who need to be protected. .
:AL underreporting value ≤ 2 ppm; AH overreporting value ≤ 4 ppm
The recommended unit for setting up alarms for toxic gases is ppm. Based on the human exposure limits, the first and second alarm levels for benzene are 1.7 and 3.4 ppm respectively; it is advisable to set the alarm values for toxic gas detectors on-site at 1.5 and 3.0 ppm.
According to the latest standards, the PC-TWA value is 3 mg/m³, and the PC-STEL value is 6 mg/m³