A few weeks ago we were debating in my FaceBook Group about these vaults being a PRCS. The picture in question (shown to the left – full scale in the article) had a working platform just a little more than 4′ down inside the vault, but the fixed ladder went all the way down to the bottom of the vault, approximately 12′ – 14′ deep. The platform was built with steel grating. This meant (to me at least) that the vault was one (1) – a single space as a worker on the platform would be exposed to the same hazards below the platform (e.g. an explosion/flash fire in the bottom of the vault would impact the worker on the platform). This became a heated debate, which really surprised me as were are still debating what a CS and PRCS are in the Year 2020! But as usual, there is an OSHA Case file that I base my argument on. My apologies for the late post!
The case involved a worker using a piece of NON-RATED electrical equipment inside the vault, which held an underground gasoline storage tank at a gas station. The NON-RATED electrical equipment ignited the gasoline vapors that had found their way into the vault and accumulated to make up at least 1.5% of the atmosphere in the vault (e.g. gasoline’s LEL is 1.5%). Gasoline vapors are 2 X’s heavier than air so they accumulated on the floor of the vault, which just happened to be where the NON-RATED electrical equipment was being used. The worker in the vault died and his attendant sustained severe burns, but survived. Here are the full-size picture and the OSHA Case file…
NOTE: the picture is NOT an OSHA picture and is NOT related to the OSHA Case File – it is from my Facebook Group.
