Do Mains Smoke Alarms Need Fireproofing?

Hi all,

The re-wire slowly grinds on. At the moment, I've launched headlong into fitting the (mains, interlinked) smoke alarms without thinking too much, and now I'm worrying.

The first one I've fitted is downstairs and I did it using a metal back-box with a U-shaped wooden "strap" to trap the plasterboard against the smoke alarm base when I tightened the screws. I stood back and congratulated myself at a nice neat job, avoiding those nasty plasterboard boxes, then I started worrying about the big hole I'd just made in the ceiling.

The smoke alarm instructions don't mention fireproofing, but where do I stand on the building regs (and fire safety in general)? Should I be putting something intumescent in or around the box? Some products seem to exist, but they don't seem common and I'm having trouble finding a definitive answer on the web as the whether they're needed or not.

I guess I need to get a copy of the building regs really...

Cheers,

Colin.

Reply to
Colin Stamp
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Only a problem if you have a fireproof ceilings, eg a 3 storey house or a house with an integral garage, where the garage ceiling will be firerated.

Reply to
ARWadsworth

Well when the Fire service fit their free smake alarms they put them but with self adhesive pads. I guess its only got to work long enough to wake folk up after all, if its a full blown fire then its too late in any case. Brian

Reply to
Brian Gaff

Ah, that's good then thanks. It's nice to know I won't fall foul of any regs.

Mind you, I've found this stuff now:-

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I might get some for extra peace of mind...

Cheers,

Colin.

Reply to
Colin Stamp

Yep. The alarm itself will last as long as it needs to. It was the thought of the fire spreading through the hole in the ceiling to the room above that was worrying me. The hole is quite big, since it has to have an electrical back-box in it.

Cheers,

Colin.

Reply to
Colin Stamp

BTW The regs are available online for free. Google part B.

ISTR that ceilings on "normal" houses are supposed to be fire resitant to 30 minutes.

It wight also be worth googling for "intumescent silicone" and again "intumescent back boxes" or "intumescent gaskets".

And have a look at

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from 3 storey houses I have never seen them used.

Reply to
ARWadsworth

Howcome you've needed to use a back-box at all? My Ei smoke/heat alarms allow all the connections to be made within the mounting plate so the only holes required in the ceiling are those for the cables and a couple of plasterboard fixings.

Mathew

Reply to
Mathew Newton

The alarms themselves don't need protection. In a domestic environment, the only concern with piercing the firebreak, kicks in when you have more than two stories (e.g. with a loft conversion for example), and probably in houses of multiple occupancy.

Here you go:

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Reply to
John Rumm

Thanks for that. I'll check them out. It looks like toolstation also do intumescent acrylic sealant. I've got a copy of part B now.

Cheers,

Colin.

Reply to
Colin Stamp

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for that. Looks like it'll be a damn good read :o)

Cheers,

Colin.

Reply to
Colin Stamp

My ones are Kidde. The back of the alarm is flat and the base is only about 5mm thick. The plug-in connector alone sticks about 12mm out of the back of the backplate, then it has flying leads, so you need a choc-block to connect it to the fixed wiring.

The most "impressive" thing about the design is that, to get the alarm straight on the ceiling, you have to fit the back-box at a jaunty angle. To cap it all, the angle for the heat alarm isn't even the same as the angle for the smoke alarms!

Cheers,

Colin.

Reply to
Colin Stamp

Ah, okay, I'd just assumed they were all much of a muchness with regards to design/layout.

Mathew

Reply to
Mathew Newton

Use this:

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use Firex alarms, and the pattress for those is a twist-and-click job; even easier)

Reply to
Bob Eager

Firex and Kiddie are now the same firm. Dunno who bought out who and how this will affect what will be available in the wholesalers.

Reply to
ARWadsworth

Afraid they are not:-)

The backbox does away with the surface mount patress that you have to buy for most mains powered smoke alarms.

Reply to
ARWadsworth

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