CGA TR-7

This technical report applies to 300 series austenitic stainless steel piping up to and including 6 inches in diameter, suitable for nontoxic cryogenic service, and where the design pressure stress of pipe and tube does not exceed one half of the basic allowable stress.

Small scale industrial gas installations, and in particular ones for cryogenic service, need reasonable equipment failure rates to drive risk informed frameworks for siting and guideline setbacks. Current failure rate guidance does not fit well for small scale and is unnecessarily conservative. The study of recent efforts in this area demonstrates interest but no useful guidance on approaches.

Such guidance should be practical in its application and transparent in its design basis. The publicly available Hydrocarbon Release Database (HSE Hydrocarbon Release Database, www.hse.gov.uk/offshore/statistics) (HCRD) for leak rates is used to generate a universal failure rate equation that has small scale and cryogenic considerations included.

Additionally, a simplified approach to estimate equipment limits is developed that allows for quick estimates of system aggregate risks using an equivalent length approach.

When compared to traditionally approaches to risk-informed methods, the proposed method simplifies the number of iterations required, improves both the accuracy, and reduces the subjectivity.