Hoods on downlights

[BigHammo]

I am installing 16 downlights in my kitchen (GU10), and in my bathroom, (MR16). I am hearing conflicting stories on wheher I need to install a hood over each light. There is insulation in the kitchen ceiling and of course in the Bedroom ceiling.

Do they need fire hoods? I have been told that they are not required, then someone else has told me that they are required for part P.

I cannot find anything in 7671.

Can someone point me to the right reg?

 

[Adam_151]

Nothing to do with part P, part B (fire safety) is the relevant section of the building regs, You'd be best having a quick chat to your LABC, because this is something that they tend to be hot on (pardon the pun) and different ones like to interpret the requirements in different ways

 

[Pensdown]

I can't remember the exact wording but in Part B, Part E and Part L of the 2006 revised approved guidance docs it states that the building structure should not be effected by the works and it should have the same resistance to fire, sound and heat loss as it did prior to the alterations.

So if you are going to cut 16 holes in your ceiling IMO you will need hoods.

 

[BigHammo]

So if you are going to cut 16 holes in your ceiling IMO you will need hoods.[/quote]

Sorry Pensdown, IMO is not good enough, because other electricians from my area have said in their modest opinions I don't need them. Maybe it is a location thing. My plans say that all electrics should be part P tested and checked.

 

[Pensdown]

because other electricians from my area have said in their modest opinions I don't need them. Maybe it is a location thing.

Well you could take their advice and not fit them. But before you do, I would suggest you down load the relevant docs free from ODPM web site, read them and then you will know as much as me. Once you've read them, like me you will know that to meet parts A-P of the building regs you need hoods in one form or another.

My plans say that all electrics should be part P tested and checked

Sorry to be the bearer of bad news but your electrical installation must also be designed and installed to meet all other parts of the building regs

IMO=Parts A-P of the building regs are Approved Documents only. If you don't want to fit hoods you can put your case to your building inspector but I think you'll find he's going to want them.

 

[BigHammo]

Thanks Pensdown I will look at the ODPM web page

 

[BigHammo]

I found a useful link on
http://www.iee.org/Publish/WireRegs...nstalling_recessed_luminaires_in_ceilings.pdf

It shows that if you are cutting holes in your ceilings for down lights you may be reducing the fire resistance capability of the ceiling, and that you need to install plaster board covers or install firehoods over the light. So it becomes very costly to install downlights! As firehoods cost more than the liht itself.

 

[BigHammo]

However, it also says in the same document in the TTL test section that putting fire hoods or plasterboard covers had little significant effect on the fire resistance rate of up to 30 mins. It must be inferred that with plaster board ceilings with conventional rectangular joints, it is not necessary to box in Luminares.

This contradicts what it says in the rest of the document. Another IEE meaningless document!

From this I will consult with my building inspector.

But I will be arguing the case for not installing them.

 

[Pensdown]

You’re looking on the wrong site. The building regulations say that the integrity of the ceiling must not be affected by any alterations. This includes the passage of sound, the passage of fire and heat loss It's not an electrical regulation it’s a building regulation.

You don't have to have use expensive fire hoods; you can make small boxes from plasterboard stuck together with gripfix and pop them over the lights. This would ensure that the integrity of the ceiling was the same as it was before you carried out the alterations.

 

[SIman]

I am about to install 2 downlights (GU10s) in a pitched roof/ceiling that is almost fully filled with Kingspan insulation board. How far back should the insulation board be cut for a GU10 fixture? Obviously it's a trade off between thermal performance of the ceiling and the amount of space needed to cool the fixture. Anyone know any figures for this? The ceiling is plasterboard/40mm Kingspan over rafters/90mm Kingspan between rafters/50mm air gap/felt/clay tiles. I actually only want to fit energy saving GU10s, but I guess I'll have to make the fixture ok for 50W GU10s to satisfy Mr Building Inspector!

 

[salem2000]

OP: or you could fit fire rated downlighters!

 

[Jaymack]

Don't use fire hoods. They are near impossible to fit properly and can become dislodged. Use fire and acoustic rated downlights - these are enclosed in a vented canister and fitted with intumescent material that will activate in the event of fire, much like fire door seals.

If a penetration is made in a partition (wall or ceiling) that is a fire containment barrier, the fire rating must be restored. In a single dwelling there are no such barriers, except the ceiling of an integral garage. The fact that there is a room above a house ceiling is immaterial

Normal plasterboard ceilings have a half-hour fire rating and testing carried out by the BRE has established that the installation of downlights does not significantly affect this.

So, there is no need at all to fit hoods in a single domestic dwelling (except, maybe in the garage) but not all building inspectors appear know this. If you must fit downlights, use the fire-rated ones.

But, beware, Building Regulations Part L1B, specifically paragraphs 43 - 48.

(I don't believe you can fit downlights and have a clear conscience regarding Part L)

You can read all the Building Regulations Approved Documents here:

http://www.planningportal.gov.uk/england/professionals/en/1115314110382.html

 

[dingbat]

(I don't believe you can fit downlights and have a clear conscience regarding Part L)

Hear, hear, Jaymack.

I would go further and say that you can't fit downlights, comply with all of the Building Regulations and have a clear conscience regarding following the herd rather than thinking for yourself!