UKC

I want to fit an attic mounted (inline) extractor fan to my upstairs bathroom (bog standard 2 story 30s semi). Simple job but at some point soon (when my dog stops taking all my money to the vet) I'll be doing a full rewire with building control inspection so wish to avoid annoying snags like buying the wrong fan which could cost me a re-inspection fee plus of course a new fan.

What I can't tell for sure from part B is do new penetrations through the ceiling have to be fire rated in any way, it seems farcical to have a specially rated fan/grille fitted next to a wooden loft hatch in a thin ceiling never designed to resist fire.

Can anyone confirm/clarify the position?

jk

In reply to jkarran:

Reasonably sure this only applies to floors supporting habitable space (or supporting floors that are fire exits).

It is not common practice to fire rate any structure that only supports a roof, even on large scale commercial.

I'll have a look.

Steve (a ceiling contractor)

In reply to sbc23:

Cheers, I'd appreciate that.
jk

In reply to jkarran:
Ok, my interpretation :

Your upstairs ceiling is not considered an 'element of structure' (B Vol 1- B3 4.4), therefore doesn't need to be fire resisting in itself. Downstairs would need to be 30mins - See Appendix A Table A1.

It is also not a fire-separating element.
- See Section 5, it's vague, your ceiling isn't listed.
- Also, your ceiling is not required to be fire-resisting to protect an escape stairway. Section B3 2.14 & Diagram 6 does not apply - I assume your 1st floor is not over 4.5m above the ground?

All the requirements for penetrations such as your fan are in Section 7. These do not apply because your ceiling is not a fire-separating element and you are not compromising the protection to an 'element of structure' - Reference B3 7.1

Steve

In reply to jkarran:

Don't think you need to worry.

On the extension and house I'm doing atm ( both 2 storey ) ,the bathroom ceilings are 12.5 plain plasterboard.

Ground floor ceilings are fire rated on both jobs.2 layers gyroc fireboard.

Must be going to be standard practice now. Lot of work in them ,but to be fair they help stiffen the mid-floor and help with the sound proofing.

In reply to sbc23:

Thanks a lot, that fits with my interpretation but lacking familiarity part B in particular is confusing in places.
jk

In reply to jkarran:

Specifically for your purposes, Part F1 (Ventilation) 4.37 states that ducts need to be fire-rated when passing through fire-resisting floors and walls. Presumably not when the floors are not fire-rated.

STeve