It’s not worth the candle!

A B2 fire resistance rating on a product does not mean that the product can be used to stop or protect fire.

When we do a fire risk assessment, we often make comments about how to stop the fire. In a recent job, we discussed that the additional fire needed to be stopped. The client hired a contractor who used Soudafoam. On the can he says that the product has a B2 fire resistance classification according to DIN 4102.

We were then asked by our client to update our fire risk assessment as these works had been completed.

Before signing this, we did some more research to establish what a ‘Fire Classification B2 according to DIN 4102’ meant. Din 4102 is the European Classification of construction materials according to their flammability. Classes range from A1 100% non-combustible to B3 Easily combustible. This is what we found:

Classification Degree of flammability Examples

A1 100% non-combustible (nichtbrennbar)

A2 ~98% non-combustible (nichtbrennbar)

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

B2 Normal Combustibility Wood

B3 Highly flammable (leichtentflammbar)

As you can see from this, a B2 rating is not acceptable as a firestop material and a B1, A2 or A1 rating is needed. The contractors’ supplier thought the B2 rating indicated 2-hour fire resistance and sold the material to many other contractors looking for a firestop material.

Searching for more information on Soudafoam on the website http://www.soudalusa.com we found a list of suggested uses; Thermal insulation, sound insulation and various other uses are recommended. There are no comments on fire insulation.

The B2 Fire Rated statement is obviously correct, but when searching for Soudafoam on the web, you come across an ad like this

Soudafoam 1Kb2 Fire Resistant Spray Foam

I think most people would assume that the product has good fireproof values.

To make matters more annoying, foam with the correct A1/A2/B1 rating is no more expensive than the Soudafoam product.

Selling something with a ‘B2’ fire rating when the facts are correct is highly misleading. â�¨â�¨ I posted this comment as a discussion within the ‘Fire Risk Assessors and Consultants Group UK’ on LinkedIn. I received 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 for linear gaps and BS EN 1366-3 for service penetration seals. There is a big difference between fire reaction polyurethane foams such as B1 B2 etc. and fire resistant polyurethane foams. Take a look at the ASFP Advisory Notice on the use of polyurethane foams and make sure they are applied as tested. I have had many problems with this, particularly fire door installations. Using penetrating foam to seal doors is not a supported installation…and vice versa of course. When used in door installations, the backing must, in many cases, be mineral wool topped with at least 10mm of intumescent sealant and all per manufacturer’s instructions and installed per test data. You can’t just ‘hit’ a charge of foam, in particular B2.

I hope that these comments are helpful and help ensure that the right materials are used in the right circumstances.