Regarding gas analysis before hot work, why is there a 30-minute limit specified – and when does the timing start and when does it end?
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For hot work operations, gas analysis is required before carrying out such work. Why is a 30-minute time limit specified? When does the timing start, and when does it end?
If the time is too long, changes in the environment can lead to inaccurate gas analysis results; if it is too short, it becomes difficult to complete all the necessary procedures. 30 minutes is a suitable duration. The 30-minute limit should start counting from the end of the analysis, and stop counting when the personnel begin working after all procedural steps have been completed.