In 2021, I wrote an article regarding OSHA’s Permit-Required Confined Space standard and reclassifying PRCSs to a Non-PRCS status. This article centered on the keyword “potential” when discussing a hazardous atmosphere. The intent of that article (Defining and Quantifying “potential hazardous atmosphere”) was to clarify when/how a POTENTIAL was present to create a Hazardous Atmosphere. Today, I want to discuss the other end of this risk spectrum and demonstrate how a space that normally has a Hazardous Atmosphere CAN BE RECLASSIFIED.
As I stated in the 2021 article, the concept of “potential atmospheric hazards” is real when a hazardous substance that could create an acutely hazardous atmosphere is present within the space. For me, no more explicit argument can be made that there is a “potential” when the hazardous substance is a “stored energy source” contained within piping/tubing inside the space, and such tubing/piping has never been in the MI program for testing/inspection. For us to claim “no potential,” we have to REMOVE and ISOLATE this source of “potential.” This takes me to a space that is blanketed with Nitrogen under normal conditions. Can this space be reclassified?
The short answer is yes; the space MAY be reclassified once we have ELIMINATED the potential for N2 to enter the space. How can we ELIMINATE this potential?
It goes back to the three (3) acceptable means of isolating the hazard:
- Blinding/Blanking
- Disconnect & Misalignment
- Double Block & Bleed
There is a good reason why OSHA spelled out these three (3) means of isolation, and when we use these three (3) means of isolation, we can claim the hazard has been ELIMINATED.
In 2023, I uploaded my training presentation on Energy Isolation Methods (Positive, Proved, Non-Proved) which will make sense of where OSHA came up with these three means of isolation.
Essentially, once we have isolated the N2 source into the space using one of these three means of POSITIVE isolation, then we can claim the source has been ELIMINATED. But it is critically important that the N2 be isolated using one of these three means of isolation – NO VARIATION can be allowed.
