Carloss said:
For starters they only stop the spread of fire for approx 30mins...
and for desert
the rest of the floor construction is only fire resistant for 30 minutes as thats the standard its designed to for in the average 2 storey house.
The timber flooring/joists/plaster combine to provide 30 mins fire resistance - when the holes for the plaster are made the resistance of the floor is brought down massively - ive seen test reports that found some downlights drop out in only 6 minutes
- then the fire is free to set light to your floorboards
.
The fire resistant aspect of these hoods has been required for donkeys years, it just seems that the use of downlights has exploded in the past 5 years or so hence the raised profile.
The 2003 date comes into it because in 2003 the Sound regulations were revised (again the construction of the floor timber/quilt/plasterboard combine to provide the sound resistance) and thats when the hoods were needed to provide fire
and sound resistance.
If the plaster is removed (by drilling the holes for the lights to fit in) and the quilt pulled back then the sound insulation is broken and massively less effective.
The hoods are needed to floor constructions but not in roofs (unless it the roof is needed for an escape route - some flat roofs generally).
However if you pull the insulation away from the downlights in a loft space (say form a 300mm circle with the downlight in the middle ) then the insulation in the roof becomes much less effective. The warm air from your room will escape though the coldest part - which would be the uninsulated circle around the downlights.
Carloss said:
However it is correct on what they said about them overheating the hoods just end up sitting on the downlight.
The downlight hoods are produced by several manufacturers - surely all of them cant have neglected to take the heat produced by the downlight into account?
I'd be interested to know how much space does the downlight need to release its heat?
I have heard of people placing upturned plant pots or wire planters (300mm diameter) above downlights in lofts and and laying the insulation quilt over these - would that give the light enough room to release its heat?
Several manufacturers now make downlights that have the fire and sound resistance built into the downlight unit rather that needing separate hoods and these overcome all these issues as i understand - happy days