Abstract: In this paper, the ALARP principle for acceptable risk assessment of oil and gas pipeline and the method of defining tolerance limit and neglectable limit of risk are described through combining the FN criteria, the acceptable risk probability standard values by adopting category zoning and acceptable risk assessment index standard scores are defined by using ALARP utility function theory. The former solves definition of risk probability standard value in the absence of information in our country, the latter answers how the acceptable risk standards of the current evaluation model functions in practice, which is of great significance for improving oil and gas pipeline risk assessment of the quality.

Key words: acceptable risk, standard value, definition methods, utility function, oil and gas pipeline