The British Standards on fire performance testing of external cladding have now been revised

In the wake of the Grenfell Tower fire in June 2016, it was clearly important to review all the industry comments received on the two British Standards that describe fire performance testing of external cladding. This blog post explains the standards and looks at what the revisions have changed.

Two British Standards – first published in 2002 – deal with how to test the reaction of external cladding to the spread of flame. These standards were subject to heightened scrutiny after the Grenfell Tower fire in 2016. Although there’s no evidence that the Grenfell Tower cladding system was ever tested using these standards, comments received from the industry were nevertheless reviewed. The resultant revised standards are: BS 8414-1:2020 Fire performance of external cladding systems – Part 1: Test method for non-loadbearing external cladding systems fixed to and supported by a masonry substrate and BS 8414-2:2020 Fire performance of external cladding systems – Part 2: Test method for non-loadbearing external cladding systems fixed to and supported by a structural steel frame.

What do the standards cover?

BS 8414-1:2020 provides a test method for determining the fire performance characteristics of non-loadbearing external cladding systems, rainscreen overcladding systems and external wall insulation systems when fixed to and supported by a masonry substrate and exposed to an external fire under controlled conditions.

The peak fire exposure is representative of an external fire source or a fully-developed (post-flashover) fire in a room, venting through an aperture, or from an external fire source, that exposes the cladding to the effects of external flames.

BS 8414-1:2020 is solely intended to give an indication of fire spread across or within an external cladding system. The purpose of the test is to provide data that enables evaluation of the fire performance of the cladding components tested in combination.

Likewise, BS 8414-2:2020 provides a test method for determining the fire performance characteristics of non-loadbearing external cladding systems, this time fixed to and supported by a structural steel frame when exposed to an external fire under controlled conditions.

Again, the peak fire exposure is representative of an external fire source or a fully-developed (post-flashover) fire in a room, venting through an aperture, or from an external fire source that exposes the cladding to the effects of external flames.

BS 8414-2:2020 is solely intended to give an indication of fire spread across or within an external cladding system. The purpose of the test is to provide data to enable evaluation of the fire performance of the cladding components tested in combination. It doesn’t apply to non-loadbearing external rainscreen overcladding systems or external wall insulation systems applied to the face of a building, the fire testing of which is covered in BS 8414-1.

More resilient infrastructure

The standards are written to be used by UKAS accredited testing laboratories. They will also interest fire and rescue services, local authorities and fire engineers. Both contribute towards the achievement of UN Sustainable Development Goal 9 by promoting the construction of more resilient infrastructure.

Their key objective, however, is to provide test sponsors with data on how cladding reacts to the spread of flame. In doing so they help manage the risk of and increase trust in an external cladding system.

As stated, a panel of experts representing regulators, industry, academia and fire rescue services undertook a thorough review which considered and reviewed all the comments raised after June 2016. The subsequent revisions made amendments to Clause 6 on test specimen and expanded both Clause 9 on post-test examination and Clause 10 on test reports. The standards now reflect all the comments and proposals that were applicable.

 Learn more about BS 8414-1:2020 and BS 8414-2:2020 or order now