Abstract:

This paper analyzes the principles of toxic hazard classification for pure substances and mixtures as outlined in GB/T 42594-2023 - Guidelines for Classification on Hazard of Medium in Pressure Equipment, and discusses their rationality and applicability to corresponding pressure vessel scenarios. This standard is compared with HG 20660-2000，HG/T 20660-2017 and GBZ 230 in terms of the classification of toxicity hazard degree of medium in pressure vessels. For the mixtures containing definite human carcinogens, two methods are supplemented to classify the toxicity hazard degree of medium. The toxicity hazard characteristics of benzene, ethylbenzene, butadiene, hydrogen sulfide and ethylene oxide are analyzed. The influence of the classification of acute toxicity hazard of medium and the grading of hazards of occupational exposure to toxicity according to GB/T 42594 on the technical requirements of pressure vessel manufacturing in petrochemical plants, as well as the effect resulting from significantly improving economic efficiency are expounded.

Key words: pressure vessel, acute toxicity, hazards of occupational exposure to toxicant, toxicant hazardous index (THI), acute toxicity estimate (ATE), mixture.