Select Committee on Environment, Transport and Regional Affairs Minutes of Evidence


Memorandum by Eternit UK Ltd (ROF 03)

INTRODUCTION

  The Cladding Division of Eternit UK Ltd has been promoting External Rainscreen Cladding Systems for high rise refurbishment for over 18 years. In excess of 50 such residential tower blocks, throughout the UK, are benefiting from energy conservation, elimination of moisture ingress, prolonging the life of the main structure and external revitalisation from our Overcladding Systems.

  As well as our own Research & Development Division and Specialist Consultants, the design and development of these systems involved the expertise of the Building Research Establishment, Fire Research Station and Warrington Fire Research Centre.

  As early as 1991, Eternit UK commissioned the first full-scale fire test on our Cladding Panels & Systems using a four-storey construction.

  In recent years we have been one of the Industry Partners supporting the DETR project, under the Partners in Technology Programme, culminating in a draft fire test. "Test method to assess the fire performance of external cladding systems"—Fire Note 3 published by the BRE/FRS.

ASSESSING THE RISK

  Whilst there is a clear distinction between a total External Cladding System and partial window refurbishment, like the recent incident at Garnock Court, Irvine, both should be regulated by the Approved Documents. The materials used on a high rise structure, at the surface and within the cavity, should not pose any significantly greater risk than the current facade.

  The above Test Method provides an effective measure of the system's performance in relation to fire.

EXTENT OF EXTERNAL CLADDING SYSTEMS

  "Up to 4,800 tower blocks of more than six storeys were built for council tenants between 1959 and 1967" [Study carried out by South Bank Polytechnic]. Whilst some of these may have been demolished, it is estimated that in excess of 350,000 individual flats still remain. External refurbishment of these types of building can take two principle forms.

    Insulated Render Systems.

    Rainscreen Cladding Systems.

  Whilst no official figures are available our estimate is that up to 2 per cent of these multi-storey blocks have been externally refurbished, half of them with Rainscreen Cladding.

EXISTING REGULATIONS

  The current Approved Document "B" provides extensive guidance on the performance of the external cladding panel, the contents of the cavity and the use of cavity fire barriers. Generally if these criteria are met, the reaction to a fire event has been proven as no worse than the existing facade.

  Control tests in the PiT's programme demonstrated that flames from a severe flat fire impinged over 2 metres above a window opening thus placing the next storey window at risk no matter what the external wall surface.

  Demonstrating that all future Cladding Systems have a satisfactory performance to the proposed Test Method will provide further reassurance to the Building Owners and their Residents.

REDUCING THE RISKS

  Whilst External Cladding Systems are designed to reduce the spread of fire, both on the surface and within the cavity, many other precautions can be adopted to minimise fire incidents:

    Non combustible wall construction at ground floor level—start the cladding system above first floor level.

    Control the disposal of large items of combustible waste from the residential block—old furniture, etc.

    Landscaping or physical deterrents to avoid vehicles being abandoned and torched next to a tower block.

    Improvement to caretaking facilities, security, external lighting and CCTV.

  In our experience this "total" refurbishment approach, carried out on most of the projects we have been involved, has given a pride to the residents which is reflected in significant reductions in vandalism, malicious fires and damage.

FUTURE REFURBISHMENT PROJECTS

  The adoption of the "Test method to assess the fire performance of external cladding systems" will ensure that a high standard for cladding systems is maintained.

  Direct encouragement/promotion of the Centre for Window and Cladding Technology's "Standard for Walls with Ventilated Rainscreens". The comparable British Standard 8200 is so vague and out of date that it's current value is debatable.

  Whilst we feel that our views are fully represented by the Fire Research Station and Fire Safety Development Group, Eternit UK Ltd would welcome the opportunity to offer further information on this important topic.

Martyn G Rich

Technical Applications Manager

July 1999


 
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Prepared 17 August 1999