Our industry has seen a recent increase in regulatory emphasis on relief device installations, ensuring that the 3% rule is being followed. For those who are not familiar, the 3% Rule is the current RAGAGEP installation criteria that dictate when relief devices are being installed and flowing at full capacity, the inlet piping produces a pressure drop no greater than 3% of the relief device’s set pressure. The primary goal of meeting this 3% rule is to ensure that relief valves operate in a stable manner. Fortunately for our industry, quite a bit of research has been conducted on relief valve devices’ stability over the past decade.

However, said stability research suggests that a significant number of a facility’s relief valves could experience destructive chatter, leading to a loss of containment. If this research is applicable, these studies represent a major concern, represented as reoccurring industrial incidents. Although, our review of the facilities’ “incident data” and “repair data” tell a much different story.

  • Why are these studies reporting a high probability of destructive chatter in relief valves?

  • Is there something missing in the research that could explain why destructive chatter is not a larger industry occurrence?

  • Does the industry need better tools to accurately predict the incidence of chatter?


At the end of 2015, John and I decided to find the answers to these questions. So we built our own “relieve valve laboratory” where we could actually test a variety of devices’ stability in a simulated industrial environment. We set out with the hope that our experiments will help bridge the gap of knowledge between the existing research and real industry practices. 


In the coming months, look for our results to be published in several peer-reviewed journal and industry magazine articles. We plan on diving into these topics over a series of blog posts that will help you the reader make sense of the current situation, what the data says, and how to move forward with your facilities.

However, in the meantime, we plan to supplement those publications with extra content. For those who are interested in keeping up to date with our research findings - sign up for our mailing list below: