Ceiling sprinkler head looks like it keeps getting lower, is it going to go off?

January 29, 2009 5:21 PM

My apartment has a ceiling sprinkler system and one of the heads that has descended slightly from the ceiling. Should i worry that the sprinkler head will go off?

I recently moved into a new building with a sprinkler system in the ceiling. One of the sprinkler heads has descended from the ceiling about an inch. I can see metal grooves but can't see the actual sprinkler head. My super says not to worry, is there a chance this one sprinkler head can go off by itself? While the sprinkler head is near the kitchen there is another sprinkler head almost above the stove that is flush with the ceiling.

posted by slhpatterson to home & garden (9 answers total)

You sure it's not just a high spot in the ceiling? Most of the time the heads are all set at one elevation, then they drywall (or lay-in-tile) around 'em. Especially if it's layin tile ("drop ceiling" in the parlance), the wires that support the grid may be a little tight there.
posted by notsnot at 5:32 PM on January 29, 2009

What metal grooves and sprinkler head are you talking about? Can you find a Google Images shot that explains it?

I'd expect to see the metal grooved disc extending at least an inch from the ceiling. If the metal disk were completely recessed with the ceiling tiles, the water jet would be contained within the cut-out hole and end up more of a water 'pour', no?
posted by anthill at 5:38 PM on January 29, 2009

i realize that i forgot to mention the sprinkler has a white cap and that's what is descending. i have uploaded a pic from my phone to flickr: http://www.flickr.com/photos/slhpatterson/3237236845/
posted by slhpatterson at 5:57 PM on January 29, 2009

i'd also note the head is about a half inch out of the ceiling in that pic
posted by slhpatterson at 6:00 PM on January 29, 2009

Are you looking at a concealed sprinkler head? Maybe the cap just came loose, can it be pushed back up? Or maybe one of the hangers that hang the sprinkler pipe from the structure above the ceiling has come loose, causing it to descend.

In any case, I wouldn't worry about it too much. The head isn't likely to blow accidentally unless something very jarring strikes it or pressure builds in the pipe (like in a pipe freeze). Just to be sure, keep a look out around ceiling near the head itself for water stains. That will mean that there's a slow leak on the pipes someplace.
posted by spoons at 6:06 PM on January 29, 2009

thanks for the responses, i have thought of pushing the back into the ceiling but didn't know if it would cause the sprinkler to go off somehow. from other things i've read online it seems the malfunction rate for these things is 1 in 16 million... i didn't see any water stains, i will keep an eye out for them though.
posted by slhpatterson at 6:31 PM on January 29, 2009

That is a concealed head for sure. If it really bugs you, go ahead and smoothly and firmly see if it pushes back up.

Sprinkler heads (generally) work by having a small glass fuse that is designed to break at a certain temperature. They are more durable than you think, and usually resist any incidental contact.

On the other hand, from your picture it looks like it was down when they painted the ceiling, so probably is fixed in their pretty good. Also, sprinkler pipe is usually pretty rigidly installed, so it is quite possibly not going anywhere.

If you don't mind the look, just ignore it. There is no reason to think the lowered cap will increase the likelihood of it going off.
posted by meinvt at 8:05 PM on January 29, 2009

If that happened while you were there, that sprinkler is improperly installed, as it is
supposed to be much more firmly attached than that. Report it to your landlord in writing,
and send it by certified mail. Don't threaten or diagnose, just note its appearance, as if
you were concerned about a deposit. I would be more worried about a leak from an improperly
secured pipe and fitting than I would about a sprinkler going off accidentally, and I
wouldn't even worry much about that. The system is supposed to be tested to 175 psi,
or 50 lbs over the working pressure, whichever is greater.

If it is an NFPA 13 compliant system, it's probably plastic pipe up there, and in some
jurisdictions it could be PEX, which is a semi-flexible crosslinked polyethylene pipe, and
the fact that it is sagging could indicate an anchoring problem. Same story with CPVC,
which is orange and nominally "rigid". Pipes are supposed to be supported rather
close to the drops that feed the sprinkler heads, and that kind of sagging should
not be possible. Sagging is not a problem with black iron or galvanized pipe.

It is a "concealed" sprinkler head. The sprinker fitting is attached to that ribbed thing
that you show, from a side view. The cap, that you would see from below, slips into
that ribbed thing. The end of the cap is held in place with a very low temperature solder
that is designed to melt about 20 degrees before the sprinkler goes off. When the cap
falls off, a little deflector drops, by gravity, below the level of the cap, to properly disperse
water when the sprinkler goes off.
posted by the Real Dan at 10:10 PM on January 29, 2009

I lived in an apartment that was flooded by the sprinkler system. Make sure you have renters insurance. Seriously. You can get it bundled with your car insurance and it's cheap.
posted by princelyfox at 8:53 PM on January 31, 2009