Dichroic halogen lamps in fire-protection downlights

[Dippy]

I'm in the middle of a discussion with my LABC about fitting downlights. The surveyor has told me that "the first floor only requires to have a modified half hour fire resistance" and that to achieve this I might need to use fire hoods.

My dilemma is that I really would like to use the Philips or Osram higher efficiency halogen lamps. As I see it, although these use some sort of coating to reflect all light to the front, they are still dichroic so allow the heat out the back.

The fire-protection lights I have looked at (Scolmore) tend to come with aluminum reflector lamps. Although nothing in the literature says so, I presume that dichroics are not recommended because all that heat will get trapped in the fitting. Can anyone comment on this?

I really don't want to go to the expense of fitting hoods so I'm left with either using low-efficiency halogens or else not using downlights at all.

This is for a two storey detached house so from the comments on here I understand that my ceilings do not need to be fire-rated. Does anyone think I would have any chance of arguing the matter with the LABC?

 

[Adam_151]

//www.diynot.com/wiki/electrics:lighting:gu10_and_gz10

As far as I understand it 'normal' GU10 lamps are PAR, not dichoric, the phips/osram lamps ought to say on them if they are different, if you are unsure still, try getting in contact with the companies concernered?

Unless a fitting states its suitable for dichroic lamps, then you have to assume its not suitable for them

And as far as I understand, your upper story ceiling isn't required to have a resistance to the passage of fire, but different BCs have different takes on the rules, what had he made of attic trapdoor?....

Some sort of box to the clearnaces recommended by the lamp manufacturer is to be recommended in the attic space, because A) the fire protection part only stops fires that have started spreading, it offers no protection against hot fittings setting stwoed away christmas decorations alight and B), you'll have great difficultly complying with part L of the regulations otherwise (perhaps ask the BC on his thoughts re: part L?)

 

[Pensdown]

You don't have to use off the shelve fire hoods. Because the hoods will be in the loft you could make them 600mm square if you wish.

1/2 inch fire board bonded together with an intumescent sealer to form a box would give you an 1hr fire rating.

 

[Dippy]

I did a bit more research and it seems that whilst some manufacturers state that you can use a dichroic in their fire-protected downlighters, they do advise against it. I also had some more technical advice that these infra-red coated halogens are more energy-efficient because the filament runs hotter than normal halogens. So it looks like energy-efficient halogens and fire-protected downlights just don't mix.

The BC surveyor has clarified that "the first floor only requires to have a modified half hour fire resistance" is referring to the ground floor ceiling, not the first floor ceiling. He specifically stated that the ceiling above which there is a habitable space needs to have modified 30 min resistance, and it is pretty clear that he will not budge on that.

So it looks like I'll be using fire hoods.