There are several of these in the building where I work. They are stainless-steel metal plates about the size of a dinner plate, with a single screw in the center.
They are mounted around 8-12" off the floor.
I see them all of the time in other commercial buildings.
Rather than go at one with a screwdriver and engage the wrath of many, I am asking here…
What are they?
My theories:
[ul][li]A funky quick fix for a small hole in the wall. Doesn’t make sense because they have a good crew of maintenance folks here who refurbish offices overnight. Why would they use a lazy quick fix?[/li][li]A cover for a no-longer-used outlet. Why not just a blank outlet cover then?[/li]A valve resides behind the plate. Why would the screw be in the center?[/ul]
Could they be reflectors for some kind of beam-break alarm sensor? Is there anything on the wall directly opposite?
No. These are nothing special: just stamped steel round plates with bevelled outer edges and a single screw holding them to the wall. They very in size too: I have seen them anywhere from 8-12 inches in diameter.
Plumbing clean-outs.
More precisely, roof drain clean-outs.
Here is a picture of such a cover plate.
In this picture, the square on the right side of the clean-out plug will have a threaded hole in it (field installed) for the insertion of the screw that holds the stainless clean-out plate in place. The drywallers will frame out around the (clean-out) plug so the plumber can come back later and tap the square part of the plug and install the cover plate.
