Hi guys I just want some clarity on fire sealing, I know it’s meant to be done where we may need to penattrate a fire barrier to run a cable. My confusion exsists where we have an upstairs ring circuit with a fused spur down stairs. I know firerated downlighters must be used where a habitable room is above but how can we relate fire sealing to the rest of the property?
Thanks
J
My understanding is that If it's a domestic house you're talking about then it's unlikely that the floors are split into fire compartments, so you wouldn't be penetrating a fire barrier.
In a house, the only occasion I believe fire rated downlights are actually needed is where there is a habitable room above a garage - in which case a fire barrier should be in place between them when it was built. Any breach of that barrier then needs to be kept to the same standard of fire safety, which would mean fire rated downlights
if the plasterboard is the barrier, and suitable fire sealant around any pipes/cables going through them.
There may be other occasions, for example when loft extensions are added, and fire doors required under building regulations, but don't have enough experience to comment on those.
Maisonettes, flats are different - but when purpose built the barrier is usually constructed with concrete rather than relying on plasterboard - and usually circuits don't cross between them.
Doesn't mean that fire rated downlights aren't a good idea - though the main issue with downlights downstairs was the older halogen ones melting the (usually poorly installed) cable due to heat - that rarely happens with LED technology now. And the fire rating of a downlight is more to do with whether it will let smoke/etc through the gap, than how likely they are to burst into flames themselves.
So the simple concept is that if a fire barrier is penetrated, it must be sealed with something of similar or better rating to ensure the fire barrier is not compromised.
