BSI calls for input to develop new standard on the extended application of fire performance results for external cladding systems

08 February 2019

A new standard for the extended application of fire tests results for external cladding systems, known as BS 9414 Fire performance of external cladding systems – Extended application of results from BS 8414-1 and BS 8414-2 tests, is now open for public consultation. Views are being sought from industry practitioners, regulators, fire safety specialists and consumer organizations. The consultation is open until 8 April 2019 and comments can be submitted online at:

BSI was requested by the Ministry of Housing, Communities and Local Government to work with a broad range of stakeholders to produce a standard approach to the extended applications of relevant results from BS 8414 tests, following the tragic fire at Grenfell Tower in West London on 14 June 2017.  

External cladding systems are composed of a number of individual products (cladding, insulation, fixation systems, substrates, cavity barriers etc) intended to improve weather resistance, thermal performance and the appearance of buildings.  BS 8414-1 and BS 8414-2 provide test methods for determining the fire performance characteristics of non-loadbearing external cladding systems, rain-screen over cladding systems and external wall insulations systems when applied to the face of a building and exposed to an external fire under controlled conditions.  The fire exposure is representative of an external fire source or a fully developed (post-flashover) fire in a room, venting through an opening such as a window aperture that exposes the cladding to the effects of external flames, or from an external fire source.

When a building incorporates an external cladding system which has been tested to BS 8414, modifications may be necessary to products, constructional dimensions or both.  The number of such changes can vary according to the complexity of the external cladding and the type of construction being considered; however, every component of the external cladding could have an impact on the fire spread performance of the system. Therefore each change should be the subject of a separate evaluation when considering extending the scope of the original testing. 

This new standard, BS 9414, will provide the guidelines which should be applied when assessing the implications of modifications in relation to cladding systems which have been subjected to single or multiple tests in accordance with BS 8414 part 1 or 2. 

It should be noted that BS 9414 relates only to the extension of results of an external cladding system which has been previously tested in some form in accordance with BS 8414-1 or BS 8414-2.  It does not provide a means of assessing external cladding constructions which incorporate multiple systems. 


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