Safety Knights

For reclassification, there can be no potential for a hazardous atmosphere - either there's a potential or there's not. Essentially, if you're reclassifying a PRCS, you're saying it's now a non-permit confined space, so there can be no actual or potential serious safety or health hazards, including hazardous atmospheres. This can be done if there is no potential for a hazardous atmosphere whatsoever, and ALL OTHER hazards have been eliminated without entering the space.

If there is still a potential for a hazardous atmosphere, it can be controlled 100% by ventilation alone, AND there are no other potential hazards, then you would follow the alternate procedures mentioned in 1910.146(c)(5).

Keep in mind that when you reclassify a space, you elimiate the requirement for a permit, attendant, rescue service, etc., so ensure it's the best decision to do so. Not saying you can't, as I've reclassified lots of PRCSs, but some non-permit spaces may still be challenging from a rescue point. For example, if it's a worker(s) at remote areas or in a non-permit space that's 10+ feet off the ground or complex to manuever through, those could pose a major risk due to space access issues during a medical emergency.

It wouldn't let me comment on the thread again, so starting a new chain.

But yes, that's correct. If the tank was refilled by piping, there would still be a potential because you'd have to isolate (blank) the piping to prevent anything from coming into the tank, so there's still a potential hazard that you're having to control. The isolation device (e.g., blind) could've been installed incorrectly and still allow diesel vapors to seep past and accumulate inside the diesel storage tank.

I think this LOI is addressing reclassifying a space where the liquid is water and wouldn't create a hazardous atmosphere when present. So it's saying LOTO is sufficient for reclassifying in the scenario in the letter... https://www.osha.gov/laws-regs/standardinterpretations/2012-05-08