In situations where multiple gases (vapors) may be present in the working environment, how should gas analysis for hot work be conducted?
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For hot work 26, in situations where various gases (vapors) may be present in the working environment, how should gas analysis be conducted?
If mixed steam is complex, it is still necessary to first determine the composition and respective concentrations of the gases (sampling for chromatographic analysis can be used). Then, based on the explosion limit of each gas (steam), if the explosion limit is 4% or higher, the concentration being measured should be below 0.5%； For those with an explosion lower limit of less than 4%, the concentration to be measured should be below 0.2%. Advice should not be generalized.
Sampling can be carried out on-site using a sampler; after analysis with a chromatograph, the concentration of each gas in the mixture can be determined. When the lower explosive limit of the gas or vapor being tested is 4% or higher, its concentration should not exceed 0.5% (by volume) to be considered acceptable； When the lower explosion limit of the gas or vapor being tested is less than 4%, its measured concentration should not exceed 0.2% (by volume) to be considered acceptable. A mixed gas is considered to have passed the test only if the gas with the lowest lower explosive limit in that mixture meets the detection requirements.