Fire Hoods and Fire rated D/lights

[martysparky]

If installing fire rated Down lights are fire hoods still required to protect against the thermal effects from the transformer?

If so, do they make them with transformers already protected against the heat emission as the fitting itself?


Any help in this area would be appreciated.


Thanks.

 

[opm electrical]

i would say so cos fire rated lights are only fire rated as they have a compound at the very top of the light that expands and seals any gaps in the event of a fire to seal the gaps between flloors to stop fire spreading through. so it doesnt help with thermal effects in my eyes, but also its not the tranny that is the heat problem its the lamps. they are a rip off though, pactically double the cost of the lihgt fittings

 

[Smugley]

opm, I think you're right there. I reckon there is quite a bit of misunderstanding about fire-rated downlights. I've yet to be convinced that there is a product on the market which can safely be installed directly under insulation. As far as I can tell, the fire rating is ONLY to prevent the progress of fire through the ceiling. They do not prevent the starting of fire due to overheating. I believe even fire-rated downlights need to have adequate ventilation around them and should not be in contact with insulation, dust, mouse droppings, or anything else in a loft space or ceiling void that may be combustable. Please someone tell me if I'm wrong, cos it would make like easier if I was!!

 

[rocker]

Yea I'm seconding smugley there. Fire ratings are purely to stop a fire in the property spreading through the holes in the ceiling easily. You normally find written in the bumf that they will hold back a fire for 60 minutes (long after the wooden tounge and groove ceiling has gone). They aren't designed to stop the tranny or the luminaire itself catching something on fire such as insulation; they aren't designed to put insulation over - as far as I'm aware nothing is safe to put insulation over.

Apparently a clay plant pot (with a hole in the bottom) is just as good as a fire hood. When I first heard this I laughed, but if you think about it it's been fired in a kiln, it's pretty resilient to heat. Don't know how they would hold up in an inspection, mind....

 

[bugsy]

Fire and acoustically rated downlighters function is to maintain the fire / acoustic ratings of the ceilings ,
Do not cover the transformers , the do generate heat but this heat needs to be disapated otherwise the internal thermal loads will start kicking in and they will cut out.

 

[martysparky]

Just wondering what the recommended air space is around the accessories.

I would avoid covering with insulation in any circumstance.

I would much rather put a secondary ceiling in place and improve on the fire resistance of the building.

Fire hoods always a good choice then, I guess compulsory really.

actually on that tip are hoods needed with a secondary ceiling if there is plenty of ventilation. I.e. open around the sides? Not that I would do this in a kitchen because of condensation from the cooker.

Thanks for the input guys.

 

[GaryM]

Fire rated fittings or fire hoods are only required when compromising the fire resistance between fire compartments.

A standard two storey house is one single fire compartment so not required.

If it has an integral garage with a room above then the garage is one compartment and the house is another. Should you foolishly want downlighters in the garage then fire rated fittings or hoods would be required.

 

[martysparky]

Fire rated fittings or fire hoods are only required when compromising the fire resistance between fire compartments.

A standard two storey house is one single fire compartment so not required.

If it has an integral garage with a room above then the garage is one compartment and the house is another. Should you foolishly want downlighters in the garage then fire rated fittings or hoods would be required.

Its my understanding that a modified 30 min rated light is required over any room with a room above and the only N/A is the roof itself. Also that fire rated are not required if a secondary ceiling is used because the designed structure remains unaltered.

but, was wondering if that means no fire hoods are required either. I would think not but am not absolutely sure.

 

[GaryM]

Its my understanding that a modified 30 min rated light is required over any room with a room above and the only N/A is the roof itself.

That's incorrect.

If you're worried about the spread of fire then don't look at the big hole caused by the stairs!

 

[Doomed]

I think gary is right, but I always use fie rated cans anyway, bugger the cost, do quality work!

 

[GaryM]

I always use fie rated cans anyway

So do I as I find them to be of better quality without that much of an impact to price.

 

[martysparky]

I think gary is right, but I always use fie rated cans anyway, bugger the cost, do quality work!

Don't mean to be argumentative but just checked best practice guides and I think I'm right.

If your using them anyway no worries better to be safer.

I think if your concerned about the stairs being open its recommended to apply double plaster boards walls and ceiling and fire rated sockets too in that location if penetrating the wall cavity.

oh, and don't forget the fire rated expanding foam for termination holes.

 

[GaryM]

Forget best practice and check Building Regulations.

You seem to want to treat each room as a separate fire compartment

 

[bugsy]

So what are veiws regarding 3 story domestics?

 

[martysparky]

Forget best practice and check Building Regulations.

You seem to want to treat each room as a separate fire compartment

I think I know what you mean but after studying the best practice guide I have it down as thats the way.

After all those guides are supposed to be leading the way to new up and coming regs.

I think the moral here is if its safer then its better practice.

Just a my thoughts and thanks for the input.

So what are veiws regarding 3 story domestics?

As far as I can make out reading it sideways much the same.

Best Practice Guides | Electrical Safety Council

 

[bugsy]

Only BPG suggests downlighters with integral protection, and I wondered hw the flower pot brigade got round the situation

 

[martysparky]

Only BPG suggests downlighters with integral protection, and I wondered hw the flower pot brigade got round the situation

I guess they could take the BS number off the packaging of the light accessory and apply it to the flower pot. lol
or say it was part of the existing installation as they only changed the accessory. phhhh

 

[ezzzekiel]

the problem is usually i go to look at a job where the customer has just bought 20 dl for a fiver off ebay good deal straight from china

 

[sparks1234]

You can also argue the fact if you have tongue and grooved boards upstairs

 

[martysparky]

You can also argue the fact if you have tongue and grooved boards upstairs

T&G Boards where? floor, ceiling, over plasterboard, No plasterboard?

Did you do it? ect

Good point...