SAFETY IN THE PLANT
RELIEVING CONCERNS
Challenging the common misconceptions of pressure relief devices: rupture discs versus buckling pin relief valves
R
upture discs and buckling pin relief valves (BPRVs) are the two major primary relief devices used to protect a wide range of
applications from potentially serious over-pressurisation. According to ASME VIII Division I, either may be used as a primary pressure relief device, so dependent on the application, process conditions or customer preference, one solution may be selected over the other. With increased customer expectations on the performance of a pressure relief solution in relation to quality, efficiency, maintenance and the environment, it is not surprising that manufacturers have been making considerable
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technological advancements to these devices. Worryingly, many customers do not fully understand the advancements in these technologies and selection may be based on out-of-date information. Here, we challenge the common misconceptions of pressure relief technology, discussing the pros and cons of both solutions to give further insight into which pressure relief solution is right for a particular application.
COMMON
MISCONCEPTIONS With both technologies benefiting from instantaneous, full-bore opening in the event of an over-pressure situation, each offers considerable advantages
over relief valves. However, there is still a concern in the marketplace over certain performance characteristics, including fatigue. Customers worry that both solutions
may fatigue over time, increasing replacement costs and maintenance time. Firstly, buckling pins cannot fatigue as they are not subject to process conditions and only buckle at the set point. Traditional, forward-acting rupture discs were more susceptible to this problem, however, the latest reverse- acting solutions outperform the original designs. Many reverse acting discs have been tested to over one million life cycles as well as benefiting from 3% tolerances, meaning there is little risk of fatigue in
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