advice needed for a fire alarm system in a thatched cottage

[a.e.s]

I am rewiring a 16th century listed thatched cottage. As part of the rewire we are installing a fire alarm system wired in F.P back to a panel. The architect has specified that we have to have a detector in each room, hallway, landing and bathroom which is to be expected, but they also want us to put a detector in the roof spaces. getting to one of the roof spaes is not a problem, as there is a hatch, but the access to the other side of the cottage is pretty much inaccessable, because of the chimney breast. Access is a gap of about 12" x 12", so I can rod across to the other side, but there is not a way of wiring and fixing a detector. Also I forgot to mention in the spec it says all cabling has to protected by galv/P.V.C conduit, to stop the rats chewing through the cable( though I will be looking to use metal copex for some of it) and we cant put in a loft hatch because the ceiling is original and builders cant touch it due to the conservation regulations. has anyone come across thiss?? I am wondering if there is any kind of probe I could place there wired from the previous detector that will detect heat rate of rise?? All help appreciated

 

[pennywise]

I would ask the architect as to how he would do it or you could get into contact with the national trust or english heritage and ask them how they would get around the problem. There must be a contact at the conservation department, you maybe allowed to apply for a slight alteration to the ceiling as long as original techniques and materials are used to alter it?. Sure you've done all this already, I can't imaging how you could do it maybe the only way is to put galv conduit from the other detector mounted on the rafters and then poke it through to the next compartment with the detector head terminated and mounted on the stop end. The conduit should hold it in place

 

[Deleted member 9648]

If this is still in the design stage suggest a wireless system to the architect,might save a lot of grief wiring although you would still have to get a detector in there somehow.

 

[a.e.s]

that is a good idea with the galv conduit, I hadnt thouth of that, though it is not at the highest point in the ceiling , nor is it fixed or the detector accessable in case of a fault, I cant see any way around this, like they say you cant please all the people all of the time. This whole job has been a real head scratcher, every electrical point we get to poses a real problem luckily the customer understands this and has been sympathetic so far!!

 

[a.e.s]

If this is still in the design stage suggest a wireless system to the architect,might save a lot of grief wiring although you would still have to get a detector in there somehow.

As far as I am aware it has to be hard wired, I did suggest this to the architect, customer and my boss but it was just brushed off with no reason. I suppose they are not as reliable as hard wired with a battery backup

 

[pennywise]

Maybe you could make a rail system with tray on its side, kopex the FP attach it to the tray then at the detector end have a short length of conduit on a pivot with a pulley system with catenary wire. So in the case of fault or maintenance you could lower the conduit and pull the tray back through the hole. Basically start getting creative with your Mecano set

 

[a.e.s]

Maybe you could make a rail system with tray on its side, kopex the pf attach it to the tray then at the detector end have a short length of conduit on a pivot with a pulley system with catenary wire. So in the case of fault or maintenance you could lower the conduit and pull the tray back through the hole. Basically start getting creative with your Mecano set

Pennywise, you are my hero!! I wish i had an imagination like yours!! Believe me, if this was my job i would love to get creative, but as my boss has priced this job I would be hard pushed to get that idea past him. I think I will go withyour original idea and wire the fp through some galv conduit and poke it on through. I know it doesnt comply with all the regs, but in this situation I personally think it is the safest and most practical way of doing things. To be honest it is only to satisfy the insurance companies, the whole area in question is very small and already has 5 smoke/ heat detectors so with it being thatched it will only be a few seconds before one of the detectors pick it up regardless of whether it had this detector or not, but lets not let common sense cloud our judgement of the situation!!!

 

[pennywise]

If only every job was on day rate and you could fettle every aspect of it to perfection any materials you want etc. It would almost make the job interesting . Hope it works, the boss will probably even object to the extra cost of the length of conduit

 

[a.e.s]

the boss will probably even object to the extra cost of the length of conduit [/QUOTE] LOL, you know my boss then!!

 

[baldsparkies]

Its going to be a pig with regards to future testing or servicing, Do you have remote led's going in on the ceilings directly below the void detectors ? The architect should address the accessability issues for you. He's the one laying down the law with regards to the design, not you.

 

[pennywise]

the boss will probably even object to the extra cost of the length of conduit

LOL, you know my boss then!![/QUOTE]

My old boss was like it now it's me sucking in between my teeth and blaming the budget

 

[wattsup]

Tell english herritage it's Polish tanoniised straw that doesn't burn, then tell them to test it. When it burns down, nip in and fix a detector

 

[chris gray]

Pennywise, you are my hero!! I wish i had an imagination like yours!! Believe me, if this was my job i would love to get creative, but as my boss has priced this job I would be hard pushed to get that idea past him. I think I will go withyour original idea and wire the fp through some galv conduit and poke it on through. I know it doesnt comply with all the regs, but in this situation I personally think it is the safest and most practical way of doing things. To be honest it is only to satisfy the insurance companies, the whole area in question is very small and already has 5 smoke/ heat detectors so with it being thatched it will only be a few seconds before one of the detectors pick it up regardless of whether it had this detector or not, but lets not let common sense cloud our judgement of the situation!!!

why dont you fit an end box on the end of the galv pipe too fix your detector to?

 

[chris gray]

ive limited knowledge when it comes to fire alarms but i get by.
we were doing one yesterday at a shop in town, the architect finally turned up with a drawing.
it had sounders everywhere but no detectors? pointed this out to him and he said that the fire marshall may of asked for it like that? (not the detector with sounder).
said he'll get back to us...

 

[a.e.s]

My boss is trying to sort something out with the architect saying that for practicalities sake we are going to need a small hatch so hopefully they will come back with the a sensible answer. If not I might just burn the cottage down, it will save me 3 weeks worth of headaches and stress lol. Shouldnt complain really it is quite nice having a challenging job that gets you thinking. Today i spent half a day trying to push 5 metres of galv 4"trunking with a manufactured 90 through a tiny roof space. Thank god for understanding clients