Integrity management tools must be fit for their intended purpose and a hydrostatic pressure test is no exception to this. A hydrotest can be designed to demonstrate an industry recognized safety factor, or an alternate safety factor that aligns with a target reliability. Hydrostatic pressure tests are a destructive test, but they can be designed and executed to minimize likelihood of unnecessary damage to otherwise benign manufacturing anomalies. In order to determine a risk balanced design, a hydrostatic pressure test must be engineered to achieve fitness-for-service goals, risk goals, as well as asset goals.
This paper presents a risk balanced design to a hydrostatic pressure test. Key technical aspects related to the science of hydrostatic pressure testing are summarized as to the affect on fitness-for service goals, risk goals and asset goals. The approach to designing a hydrostatic pressure test is demonstrated through a case study on a 326 mile (525 km) NPS 26 (DN 650 mm) pipeline manufactured using 1950’s vintage flashweld longseam.