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.