B2 Fire Rated?

Its not worth the candle!

A B2 Fire Rating on a product does not mean that product can be used for fire stopping or fire proofing.

When we do a fire risk assessment we often make comment on fire stopping. On one recent job we commented that additional fire stopping was needed. The client employed a contractor who used Soudafoam. On the tin its says the product is ‘B2 Fire Rated in accordance with DIN 4102’.

Our client then asked us to up date our fire risk assessment as these works had been done..

Before signing this off we did some further research to establish what a ‘B2 Fire Rating in accordance with DIN 4102’ meant. Din 4102 is the European Classification of building materials in accordance with their flammability. The Classes range from A1 100% non combustible to B3 Easily combustible. This is what we found:

Rating Degree of flammability Examples

A1 100% noncombustible (nichtbrennbar)

A2 ~98% noncombustible (nichtbrennbar)

B1 Difficult to ignite (schwer entflammbar) intumescents and some high end silicones

B2 Normal combustibility wood

B3 Easily ignited (leichtentflammbar)

As you can see from this a B2 rating is not acceptable as a fire stopping material and either a B1, A2 or A1 classification is needed. The contractors’ supplier had thought that classification B2 indicated a 2 hour fire rating and had sold the material to many other contractors who had been looking for a fire stopping material.

Looking for further information on Soudafoam on the http://www.soudalusa.com website we found a list of the suggested uses; heat insulation, sound insulation and several other uses are recommended there are no comments on fire insulation.

The statement B2 Fire Rated is obviously correct but looking on the web for Soudafoam and coming across an advertisement like this

Soudafoam 1Kb2 Fire Rated Aerosol Foam

I think most people would assume that the product does have good fire proofing values.

To make the matter more annoying foam with the right A1/A2/B1 classification is no more expensive that the Soudafoam Product.

To sell something as ‘B2’ Fire Rated whilst factually correct is very misleading. â�¨â�¨I posted this comment as a discussion within the ‘Fire Risk Assessors and Consultants Group UK’ on LinkedIn. I got a very interesting reply from Gordon Alexander of Gordon Alexander Associates which I copy in full:â�¨

Be very aware of the use of PU foams. They must be tested to BS 476: Parts 20/22, BS EN 1366-4 in the case of linear gaps and BS EN 1366-3 for service penetration seals. There is a very big difference between Reaction to Fire PU Foams such as B1 B2 etc and Fire Resistence to Fire PU Foams. Have a look at the ASFP Advisory Notice on Using Polyurethane Foams and ensure that they are applied as they were tested. I have had many an issue with this – in particular Fire Door Installations. Using penetration foam for sealing doors is not a compliant installation… and vice versa of course. When used on door installations the backing should, in many cases, be mineral wool topped off with at least 10mm of intumescent sealant and all as per manufacturers instructions and installed as per test data. You cannot just ‘bang in’ a load of foam – in particular B2.

I hope these comments are useful and help make sure the right materials are used in the right circumstances.