CEP Architectural Facades, the company which fabricated the panels and windows for Grenfell Tower, is conducting a thorough audit as quickly as possible of all its rainscreen cladding projects in order to fully understand the different system designs in use.
For clarity Reynobond PE, the material specified by Harley Facades, the cladding subcontractor for Grenfell Tower, is not banned in the U.K. Current building regulations allow its use in both low and high rise structures. (See extract from Building Control Alliance Technical Guidance Note below).
Further, CEP Architectural Facades is not the manufacturer of Reynobond PE. It is made in Merxheim, France by Arconic Architectural Products Europe.
CEP’s role was limited to fulfilling the order for components to the specification, design and choice of material determined by the design and build contracting team.
Investigators should focus on the whole system including insulation materials, fire barriers, fixings and railings. They should also look at the overall design and quality of installation and also at whether an assessment on the whole system was carried out.
Technical Guidance Note 18 from the Building Control Alliance, issued in June 2014 says the following:
Where the building exceeds 18m in height, the BCA recommends three options for showing compliance with paragraph 12.7 of AD B2 –
The use of materials of limited combustibility for all elements of the cladding system both above and below 18m. This includes the insulation, internal lining board and the external facing material. Smaller gasket parts and similar low-risk items can be excluded from this requirement. The definition of a MOLC is stated in Table A7 of AD B2.
An acceptable alternative approach (see AD B2 paragraph 12.5) is for the client to submit evidence to the Building Control Body that the complete proposed external cladding system has been assessed according to the acceptance criteria in BR135 – Fire Performance of External Thermal Insulation for Walls of Multistorey Buildings. The preferred method of demonstrating compliance is via a fire test carried out in accordance with BS8414:1 Fire performance of external cladding systems – Part 1: Test method for non-loadbearing external cladding systems applied to the face of the building or BS8414-2 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. The test should be carried out by an independent UKAS accredited testing body. The BS8414 tests do not give a PASS / FAIL answer because the data obtained is used by different bodies with different minimum requirements. Hence, for Building Regulation purposes, any test using this method needs to be supported by proof that the acceptance criteria of BR135 have been met. These acceptance criteria are listed in Annex A or Annex B of BR135 and include the following:
- External fire spread—determined by a 6000C rise in temperature on the external face of the building (measured at a point approximately one storey above the fire floor) for thirty seconds or more during the initial fifteen minutes of the test.
- Internal fire spread— determined by a 6000C rise in temperature on the internal face of the building (measured at a point approximately one storey above the fire floor) for thirty seconds or more during the initial fifteen minutes of the test.
- Mechanical performance—determined by an assessment of system collapse, spalling, delamination, flaming debris or pool fires.
If no actual fire test data exists for a particular system, the client may instead submit a desktop study report from a suitable independent UKAS accredited testing body (BRE, Chiltern Fire or Warrington Fire) stating whether, in their opinion, BR135 criteria would be met with the proposed system. The report should be supported by test data which the test-house already has in its possession and so this option may not be of benefit if the products have not already been tested in multiple situations / arrangements. The report should also specifically reference the tests which they have carried out on the product.