Non-combustible surface

[toasty]

Hi,

I have a query regarding what is considered as a non-combustible surface.

I know this may sound like an obvious question, but I think (for example) MDF is considered to be non combustible, even though (of course) it would burn if you put it on a fire.

So really I guess I'm asking if anyone knows what makes something 'non-combustible' in the eyes of the IEE.

The reason I ask is that I'm in the process of fitting new boiler, mains hot water, burglar alarm, home automation, rewire, new consumer unit - basically you name it, it's being changed!!

I'm going to end up with a lot of electrics all in a similar place (probably the loft) and rather than mount all the boxes, trunking etc.. on the brickwork it'll be easier to fix them to a piece of MDF or similar.

Oh, great forum by the way, been reading the posts here for a while.

Cheers
-Dan

 

[Jasonb]

To be safe you could use fire resisting MDF or ply. Either class 1 which is half hour or class 0 which is one hour fire rated.

Most good timber merchants or board specialists will have it.

Jason

 

[Lectrician]

Most surface mount kit doesnt have to be mounted on a non combustable surface.

 

[securespark]

I agree with Lectrician, but as to what is a combustible surface, basically all wood products (unless specifically treated) are combustible. Plasterboard is not, so if wood were clad in plasterboard, this would be non-combustible, eg a ceiling.

 

[fubar]

basically all wood products (unless specifically treated) are combustible.

True, but perhaps it has little bearing on electrics. One of the electrical bodies (I forget which one) undertook a study a few years back into the combustability of accessories with wooden components - both antique components and ranges currently offered by manufacturers.

The conclusion was that wood poses a very low risk of combustion and therefore meets the ignitability requirements of BS 7671 but some varnishes and polishes on antique accessories are combustible and therefore not appropriate.

I'll see if I can find the reference.

--
Michael

 

[securespark]

But isn't that why IEE banned the old wooden pattresses?

Think gyp board (thicker one) is 1/2 hour rated, too.