Proctor Group’s Fireshield membrane shows that not all reaction to fire Class B membranes are the same.
The building industry received a huge wakeup call post the harrowing incident at Grenfell. All must take responsibility for the health of future occupants, and we hope this ends this ‘race to the bottom’ where the industry searches for the cheapest products to provide bare minimum compliance.
Obviously, fire regulations have been influenced and this is a constantly moving platform of updates. Old fire regulations such as BS 476 and the likes are no longer, if ever, relevant. To say your product is BS 476 compliant, you may as well be saying ‘fish and chips’ in terms of relevance if asked about fire performance.
The regulations now refer to tests of ‘reaction to fire’ rather than fire resistance. There is some logic to this and sets a benchmark of performance. The tests determine a material’s performance on a scale from A1 to F, with A being non-combustible and F being the lowest classification.
This has driven the industry to improve their products where they are to be used in ‘relevant buildings’ which are above 11m. This is admirable, but do specifiers and clients know what it means? Further reading on this subject can be found in an article in the Fire Journal called ‘The rise of Euroclass: Inside the black box of fire testing standardisation.’
In most cases of ‘relevant buildings’, Class B-s3,d0, can be deemed the minimum requirement for building membranes. This is stated in Approved Document B, Regulation 7, where B is the minimum reaction to fire classification. The ‘S’ relates to smoke index 1-3, where 1 is better than 3 and D classifies flaming droplets. This gives stakeholders a good representation of a products reaction to Fire when tested for Reaction to Fire to both EN 11925-2 and BS EN 13501-1. With a few other exceptions, products other than building membranes need to achieve a fire classification of A2-s1,d0 to be used in external wall constructions on these buildings.
Again, this can be seen to be logical but do stakeholders understand what this means? Our earliest learnings can recognise alphabetic order where A is deemed best so better than B and therefore better than C, and so on. It’s that easy, right? However, does this really represent ‘real performance’ in a fire scenario?
Proctor Group have a range of membranes that can be used in relevant buildings which include Class A and Class B classifications. One interesting product we supply to our customers is Fireshield. This is a vapour permeable, airtight membrane that has a reaction to Fire classification of Class B-s1,d0. This can be used in buildings over 11m in ‘relevant buildings’, however many specifiers may think that Class A is better?
Testing done by APG at a well-respected University has shown the Fireshield to have very good performance in a modified corner test on a timber frame construction. This test was similar to a Single burning Item test BS EN 13823 (SBI).
Tests were carried out on another non-Proctor Group vapour permeable Class B-s1, d0 membrane. This showed breakthrough to the back face of timber frame panel in just 6 mins 20s. The tests resulted in the Structural Timber Association (STA) categorising Fireshield as an FR Build External membrane in closed panel systems for assessing separating distances of their buildings. For further details see APG website for ‘Fireshield applications in timber frame during the construction process’ paper.
The Proctor Group Technical department can be contacted for more information, or a regional sales manager would be happy to visit you to discuss your intended application. www.proctorgroup.com
