Toxic gas setpoint

Look for GBZ 2.1 and GB50493

Dimethyl disulfide (DMDS) is a toxic gas that is highly flammable and harmful to human health. For the detection and alarm values of DMDS, it is necessary to refer to relevant standards and guidelines to ensure safety. According to the provisions of GB 12476.1-2013 \"Design Code for Flame Gas Detection and Alarm Systems in Hazardous Chemical Enterprises – Part 1: Gas Detectors\", the secondary alarm value for DMDS should be less than or equal to its lower explosive limit (LEL, i.e., the minimum concentration at which explosion can occur), while the primary alarm value should be lower than the secondary alarm value. The specific values may vary depending on the industry, safety standards, and equipment requirements; therefore, it is recommended that you refer to relevant industry standards or consult professional safety engineers or equipment suppliers to obtain accurate figures. .

First, you need to know the OEL (MAC, PC-TWA, PC-STEL) values for dimethyldisulfide. 2.0.15 Maximum Allowable Concentration: The highest concentration of a toxic chemical that should not be exceeded at the workplace at any time during a working day. 2.0.16 Permissible concentration time weighted average (PC-TWA): The average allowable exposure concentration over an 8-hour workday or a 40-hour workweek, with time used as the weighting factor. 2.0.17 Permissible concentration for short-term exposure: The permissible concentration for short-term exposure (15 minutes), subject to compliance with the time-weighted average permissible concentration (PC-TWA). 2.0.18 Immediately dangerous to life or health concentration (IDLH): At the workplace, the concentration of air pollutants in the environment reaches a dangerous level, such that it can be fatal or cause permanent damage to health, or prevent people from escaping immediately. 3.0.10 When determining the occupational exposure limits for toxic gases, the highest permissible concentration, the time-weighted average permissible concentration, and the short-term exposure permissible concentration should be selected in that order of priority. 3 The first-level alarm setting for toxic gases should be less than or equal to 100% OEL, and the second-level alarm setting for toxic gases should be less than or equal to 200% OEL. When the measurement range of existing detectors is insufficient to meet the measurement requirements, the first-level alarm setting for toxic gases shall not exceed 5% IDLH, and the second-level alarm setting for toxic gases shall not exceed 10% IDLH.

This post was last edited by goldskin on 2023-7-17 23:18. It seems that no restrictions have been set in the current guidelines. This item is a bit niche; it’s best to provide the CAS number to avoid mistakes. Next, determine whether it belongs to category 1 or category 2 acute toxicity gases (judged according to Appendix C of GB30000.18). If it doesn’t belong to that category, there is no need to install toxic gas detectors.