API 1160 (Managing System Integrity for Hazardous Liquid Pipelines, 2001) and the Pipeline Risk Management Manual (3rd edition, by W. Kent Muhlbauer) are among the very few publications that have sections addressing the value of adding valves on existing liquid pipelines. These sections cite two references: the California State Fire Marshal Hazardous Liquid Pipeline Risk Assessment 1993 and the Safety of Interstate Liquid Pipelines: An Evaluation of Present Levels and Proposals for Change 1987.
This paper reviews and challenges valve placement considerations established in API 1160 and the Pipeline Risk Management Manual (3rd edition) including check valve inspection issues, valve leaks or malfunction, etc. The cost and benefit of additional valves on existing liquid pipeline systems are discussed. This paper calls for the need for further work or a collaborative study of the value of additional valves on existing liquid pipeline systems.