Alumasc Facades Latest News

External Wall Insulation – Compliance with Approved Document B – Fire Regulations

manchester ewi high-rise

There is still a lot of confusion regarding what testing and accreditations External Wall Insulation (EWI) systems need to comply with Building Regulations pertaining to fire on high-rise buildings. Here, Alumasc’s Technical Director, Mark Gibbs clarifies the situation.

Routes to compliance

For the use of EWI in high-rise constructions (i.e. buildings greater than 18 m in height), there are two routes to conformance with the requirements of Approved Document B to the Building Regulations 2010 (England and Wales) (as amended):

  1. Linear compliance – the insulation must be A1 non-combustible and the system be classified as A2-s3,d2 or better (when tested to BS13501-1 Fire classification of construction products and building elements — Part 1: Classification using data from reaction to fire tests); or
  2. BR135 route to compliance – typically used for systems which contain cladding or insulation materials which are not considered A1 or A2. Systems must be approved via a full-scale fire test to either BS8414-1 (masonry substrates) or BS8414-2 (steel framed substrates). This would be used for phenolic and EPS systems for example.

System Classifications

Alumasc’s Pro EWI systems – Silkolitt Pro, VBriQ Pro, Exicco Pro (drained cavity system) – comprise of A1-rated mineral wool insulation. These systems have been proven to achieve a limited combustibility classification of A2 (or more fully A2-s1,d0) when tested in accordance with BS13501-1:2007.

For systems that achieve this A2-s1 d0 classification, BS 8414 full-scale tests are not a requirement of Approved Document B to The Building Regulations 2010 (England and Wales) (as amended).

Where constructions do not achieve limited combustibility ratings (because they comprise insulations that, in isolation, are classed as combustible), full-scale fire tests must be conducted to demonstrate that the system is suitable for use. Indeed, Alumasc has a range of EPS and phenolic EWI systems that have passed full-scale BS 8414 tests when they have been encapsulated by non-combustible renders.

It remains to be seen whether regulations will continue to allow full-scale fire tests to approve the use of combustible materials in high-rise constructions. However, there has certainly been a recent trend for designers to avoid this requirement by specifying A1 or A2 rated systems.

For more information on Alumasc’s A2-fire rated Silkolitt Pro, VBriQ Pro & Exicco Pro systems as certified by the British Board of Agrément (BBA) without height restriction, please click here.

Get a Quick Quote for your project!

Our team of EWI experts are looking forward to receiving your request, and partnering with you on your project. Just let us know the details and we’ll get back in touch with you ASAP.