I spent several years working at semi-conductor facilities (the Cincinnati SUMCO plant was one of the finest!) and it was world’s apart from a chemical facility. When I worked in chemical plants we always used to say… “this ain’t no chocolate factory”. But when I arrived at SUMCO I swear it was cleaner than any food plant I had ever been in; yet this facility handled some of the most hazardous chemicals in my 27-year career in safety. And I am proud to say, they did it very well and taught me a lot of my “best practices” when it comes to these “highly toxic” materials. One of the debates we never settled before I left was the “under-floor” area(s) and their classification as a CS/PRCS. Here is a stock photo from Wikipedia showing what these areas look like…
By Adamantios – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=5301314
Some of these spaces are taller than others, but for the sake of our discussion lets say the space is only 5′ high/tall. There is usually a full size, actually a very tall door, that opens to allow access below the floor and above the floor at the same time. Anyone taller than say 5′ would have to crouch down to fit under the floor and as you can see the floor supports and electrical and other pipes/tubes/hoses/ductwork make entry and exit sort of like a maze. And these areas can be very large in terms of square footage, thus you or I could be a long way from the single entry/exit portal. I have seen a few of these areas that were well light; however, the vast majority of these spaces are not provided with fixed lighting. These areas are well ventilated, due to the potential for a leak of these highly toxic materials, but this is industrial ventilation – NOT comfort ventilation (e.g. these spaces are not typically heated or cooled). So is a space like this a Confined Space? Does it rise to the level of being a Permit-Required Confined Space? My analysis…