New Building Trends - use of combustible materials

[Chris Houston]

Modern buildings are increasing incorporating combustible materials.  Timber cladding, composite panels, use of expanded polystyrene external insulation, plastic flexible roofs and other plastic are being used more and more frequently.

I'd be interested to hear the thoughts of fire fighters about this, especially external insulation finish systems, where it can be difficult to differentiate between combustible and non combustible inuslation by a visual inspection alone.

I'd also be interested to see what other trends are being observed.

[james]

Chris,
A newly constructed, partially occupied residential apartment block in central manchester, callef 'The Edge' recently burned well when the external cladding caught fire. Fire extended up several floors, I think. Combustible inner core to the cladding. Looks like enforcement is restricted to writing letters to Building Control and AI's exhorting them  to consider carefully the potential for floor to floor spread externally.
I do sometimes think that developers, architects, et al push things too far while hoping that statisically they will get away with it.
Residents' group, understandably, raising one or two concerns.
I am not sure whether there will be any action on the back of this fire....a number of other developments are using the same systems.

[DF]

James
Building Control can only enforce the minimum standards of the building regulations and until the guidance of ADB is altered this type of construction will continue to be commonly used (cheap and quick).
Luckily the draft ADB contains revised guidance in clause 11.7 'In a building with a storey 18m or more above ground level, insulation material used in cavities in the external wall construction should be of limited combustibility' so we may be able to control taller buildings in the future.
Also clause 7.23 of the draft says 'At the junction of a compartment floor with an external wall that has no fire resistance (such as a curtain wall) the external wall should be restrained at floor level to reduce the movement of the wall away from the floor when exposed to fire.' Again this is useful guidance.
Lets hope this makes the final approved document so that we can enforce a sensible standard in the future.
Dave.

[Chris Houston]

James,

Have you any more info on this, perhaps a link?

"Limited combustibility"? Why not non-combustible - there's a crazy idea.  I was in Estonia recently, looking round Tallin's heritage museum I read that a law was passed in 1700 to ensure that houses were built of stone to prevent fire spread.  Perhaps we have something to learn.

[james]

Sorry Chris,

I think there is still a possibility of a court case...you know what Manchester's like.
The fire travelled up the outside in about ten minutes and did damage in some of the floors, (ie would have broken into several storeys if they had been finished and occupied.
You could try a formal letter from you employers to ask for the results of the investigation. I think it would be reasonable for a major building insurer to be interested in this sort of thing!

[wee brian]

Chris

Did you know that Mineral wool insultation is not a non-combustible material.

[Chris Houston]

Chris

Did you know that Mineral wool insultation is not a non-combustible material.

B,

No I didn't.  Would you care to clarify this point?

[wee brian]

Most mineral wool insulation products use a polymer binder to hold them together.

This means that they dont pass the non-combustibility test.

If we resticted buildings to using only non-combustible materials we would be restricting lots of products that don't really cause a problem, hence materials of limited combustibility.

[colin todd]

Well done, Wee B, I am always reminding people about this, but actually plasterboard is a better example.

[Brian Catton]

I am amazed that such competent persons are debating this subject. I remember being told at one of the early courses at the centre of excellence that all things will burn in the right circumstances. Iron and steel in oxygen etc. Perhaps I am missing something Colin?

[Chris Houston]

Brian, I don't understand why you are amazed.

Perhaps I should have been more specific.  Non combustible in air is what I meant.

[Chris Houston]

Most mineral wool insulation products use a polymer binder to hold them together.

This means that they dont pass the non-combustibility test.

If we resticted buildings to using only non-combustible materials we would be restricting lots of products that don't really cause a problem, hence materials of limited combustibility.

Which non combustibility test does it not pass?

This is news to me, I had always considered mineral wool to be entirly non combustible (in air, in normal building fire situations.)

Please tell me more.

[Chris Houston]

I have just checked out the webpage a manufacturer of mineral wool insulation.  I quote:

"All unfaced, aluminium foil faced and glass tissue faced ........ products produced in the UK are non-combustible and will achieve a reaction to fire classification of A1."

[ian gough]

Chris,
Replying to your original post:
Check out Appendix 'F' of ADB - then that refers you to the International Association of Cold Storage Contractors (IACSC) Panel Labelling Scheme. However, few brigades know much about this I'm afraid.
In my experience, Polyisoyanurate foam filled panels (PIR) have performed very well - much better than I'd have expected (2 supermarket fires I attended as o.i.c) and where they did not burn, however, other materials around them certainly did.
My research reveals that the very large lossess suffered in the 'food industry' is mainly due to polystyrene panels (EPS or XPS). These are popular for cold stores or chillers - much more so than mineral wool (MRF). The food industry does not tend to favor MRF.
A very good source of information is International Fire Consultants at Princess Risborough.
But my final point is that: if soffits and fascia boards were mineral wool or similar - we would cut down on an awful lot of serious fires where material is ignited externally, but which then spread inside roofs etc.

[wee brian]

Chris - your right - they seem to have got an A1 for all thier products now. But products from other manufacturers and products that use glass fibres instead of rock fibre may not quite hit the target.

The point I was trying to make (not very well) is that Non-combustible (Euroclass A1) is a pretty tough classification and many perfectly safe products would be discriminated aginst.

I've seen mineral fibre batts burning so I know it happens (no it wasn't in an oxygen rich atmosphere)