This is a real-life story of Elimination vs. Engineering Control
We see some odd designs in our work around the world, but recently we came across a setup that defied any logic for a relief valve design basis. For some reason, the OEM and Installer of this process equipment wanted it enclosed for “efficiency”; however, they did not feel the need to vent the relief valve(s) outside of the space/area.
To be fair, I will admit the enclosed process area is normally unoccupied. However, when the PSV lifts, the discharge is about 80-90% Nitrogen gas. This N2 is discharges into the fully enclosed area/space in volumes that could create an oxygen-deficient atmosphere within this working space. To counter this CREATED hazard, the OEM specified an O2 monitoring system and alarmpanels located at the entry doors (however, NOT ALL doors have these alarm panels!).