I found this latest Letter of Interpretation regarding PSM Battery Limits an interesting read. The scenario is VERY COMMON and I am so glad OSHA wrote this letter! OSHA reminds us that cylinders stored in the same fire area (e.g. a fire has no passive control(s) to prevent its spread) that ALL of the cylinders that could be impacted by the same fire MUST BE AGGREGATED to determine if the threshold has been exceeded. NOTE: the person asking the question appears to be wanting to lay claim that each individual cylinder (DOT 3AA-2400) will be adequate “separation”. This letter hits the following key topics:
- OSHA does not consider the cylinder design to be an effective barrier that distinguishes the boundaries of a process
- Fire scenario for cylinders under the same roof, regardless of separation distance
- Barriers must be constructed in a manner that mitigates any fire or explosion hazards to the degree that a release of HHC in one storage area will not lead to the release of HHC in the other area
- OSHA believes that an effective barrier to segregate the AHF cylinders is a wall that BOTH provides
- complete separation (e.g. to the ceiling) between your two AHF storage racks, and
- is constructed to an appropriate fire resistant rating
- Processes that contain co-located equipment, to determine the boundaries of your process you must consider hazards that could reasonably be expected to cause a release from your process.
CLICK HERE to see this LOI