# Round stainless-steel plates low on walls in commercial buildings **URL:** \ **Category:** Factual Questions\ **Created:** [January 26, 2006, 12:33pm UTC](https://boards.straightdope.com/t/round-stainless-steel-plates-low-on-walls-in-commercial-buildings/341684 "2006-01-26T12:33:42Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [January 26, 2006, 12:33pm UTC](https://boards.straightdope.com/t/round-stainless-steel-plates-low-on-walls-in-commercial-buildings/341684/1 "2006-01-26T12:33:42Z")
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] ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 26, 2006, 12:36pm UTC](https://boards.straightdope.com/t/round-stainless-steel-plates-low-on-walls-in-commercial-buildings/341684/2 "2006-01-26T12:36:10Z")
Could they be reflectors for some kind of beam-break alarm sensor? Is there anything on the wall directly opposite? ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [January 26, 2006, 12:52pm UTC](https://boards.straightdope.com/t/round-stainless-steel-plates-low-on-walls-in-commercial-buildings/341684/3 "2006-01-26T12:52:21Z")
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. ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [January 26, 2006, 1:07pm UTC](https://boards.straightdope.com/t/round-stainless-steel-plates-low-on-walls-in-commercial-buildings/341684/4 "2006-01-26T13:07:06Z")
Plumbing clean-outs. More precisely, roof drain clean-outs. ---
**Author:** ![Uncommon\_Sense](https://avatars.discourse-cdn.com/v4/letter/u/f9ae1b/32.png) [@Uncommon\_Sense](https://boards.straightdope.com/u/Uncommon_Sense)\ **Post date:** [January 26, 2006, 1:22pm UTC](https://boards.straightdope.com/t/round-stainless-steel-plates-low-on-walls-in-commercial-buildings/341684/5 "2006-01-26T13:22:05Z")
[Here is a picture of such a cover plate.](http://www.azpartsmaster.com/shopazp/Clean-Out+Cover+Plates+-+6%22+(PAS1842).html) In this [picture,](http://images.acmehardware.com/200x200/5522867.jpg) 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. ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [January 26, 2006, 2:24pm UTC](https://boards.straightdope.com/t/round-stainless-steel-plates-low-on-walls-in-commercial-buildings/341684/6 "2006-01-26T14:24:11Z")
Yup, that’s it! Thanks.