Pressure Relief Device Failure Taxonomy for a Proper Data Collection Strategy

Pressure relief devices (PRDs) are important safety devices that protect hydrogen equipment against excessive pressure increases that can damage the equipment. Typically, these PRDs are intended to mitigate overpressures caused by external fires or failures of upstream equipment. However, recent incidents indicate that PRDs are also a source of unintended hydrogen releases that can lead to fires or explosions. Furthermore, spurious opening failures can also lead to large hydrogen releases and undesired events such as a fire or an explosion. Given these new hazard characteristics, there is a need to better understand the risk-benefit tradeoff present when deciding to install PRDs in hydrogen systems; including under what conditions these devices provide a benefit. Quantitative risk analysis (QRA) provides a framework to assess the risk trade-off between the PRD capabilities to mitigate versus the times they produce an incident.

An important aspect of conducting this QRA is to establish a clear taxonomy of failure modes, failure mechanisms, and incident data to support this QRA. We reviewed hydrogen incidents involving PRDs, and used this review along with reliability engineering approaches to define proper PRD reliability taxonomies that can be used in a data collection and QRA. This presentation will summarize some of the PRD incidents identified during this review and will present the taxonomy and failure terminology identified for hydrogen PRD failure modes, operations, and incident types.