Fire alarm void protection location

[oscar21]

I'm about to start first fixing this fire alarm in the industrial unit we are wiring, at the moment its totally empty and eventually will have a grid ceiling in. The dimensions are about 12M x 5M and the loft space will be open. The (quite new) fire alarm that had been fitted (but ripped out) had smokes about a 1/3 of the way up the rafters but that didn't look right to me, I would have thought they need to go higher, maybe it was a high as they could reach, who knows.

Where would you place them this time round as someone else will be commissioning it, we just have to put it back how it was before.

 

[James]

I would either ask for a spec from whoever is commissioning the fire alarm as to where they want the cables to go.
or take them to the furthest point possible and coil a couple of meters spare, they can always cut them back.

 

[oscar21]

Not sure who is doing the commissioning to be honest, its a council building and we are doing the insurance work on it. The fire alarm looked to be all 1st and 2nd fixed when we got there but the building has been altered drastically, I think they took the opportunity to re model it completely whilst they were ripping it all out. We have to put back basically what was there before, so all smoke heads back up, all cables properly clipped etc. the only part we aren't doing is getting it up and running.

I think the original firm that did the install worked for the tenant of the building and not the council and the tenant just seemed to disappear overnight so maybe the original firm never got paid, who knows, the only reason I can think of as to why they don't just get the firm in to do it again.

Its one of those scenarios where someone says to you - "like I said the last time, cant you help us out just this once."

 

[westward10]

They should be placed within 600mm of the upper apex. Additional devices may be required so there are no "blind spots" to the coverage.

 

[oscar21]

They should be placed within 600mm of the upper apex. Additional devices may be required so there are no "blind spots" to the coverage.

Thats kind of what I thought, when I fitted an Aico smoke detector in a loft conversion last month the building inspector was adamant I got it wrong. This conversion didn't have a flat in the ceiling and it was fully apexed right up to the ridge, I knew you couldnt go any nearer than 300 to a corner and it had to be no more than 600 down so I placed it about 400 down from the apex, the inspector was absolutely convinced it needed to be at exactly 600 from the apex.

So if do the same with the heads and place two in the void at opposite ends of the room say 2M in from the gable walls that should be fine shouldn't it, 8M between them should cover everything, void height is probably 2.5M or so. So all in all there will be 2 smokes in each office void and one in the central void bit which is a lot smaller (5 in all). All the others are self explanitary.

I do like the way the MX pro is wired up though, you just fit standard bases everywhere and you an interchange the heads with beasons/sounders etc, anything you want. Not like the stupid apollo sense stuff where you have to wire a dedicated sounder base which are a pain to fit.

 

[cliffed]

I'm about to start first fixing this fire alarm in the industrial unit we are wiring, at the moment its totally empty and eventually will have a grid ceiling in. The dimensions are about 12M x 5M and the loft space will be open. The (quite new) fire alarm that had been fitted (but ripped out) had smokes about a 1/3 of the way up the rafters but that didn't look right to me, I would have thought they need to go higher, maybe it was a high as they could reach, who knows.

Where would you place them this time round as someone else will be commissioning it, we just have to put it back how it was before.

View attachment 110843

Crikey what a Mess