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It is now acknowledged that cables (electrical and optical fibre) must be considered within the scope of the Construction Product Directive. Consequently, a Euroclass system appropriate for cables is required. The system adopted for common building products is based upon the Single Burning Item (SBI) as the main test. Whether such a test is valid for linear products remains questionable. Therefore, the EN 50266-2-4 (Common test methods for cables under fire conditions. Test for vertical flame spread of vertically-mounted bunched wires or cables. Procedures. Category C; 2001. [1] ) vertical tray test, with improvements as developed in the FIPEC (Grayson SJ, Van Hees P, Green AM, Breulet H, Vercellotti U. Fire performance of electric cables – new test methods and measurement techniques (FIPEC). Final report of the European Commission SMT programme sponsored research project SMT4-CT96-2059; 2000. [2] ) project, has been suggested as the main test for cables. These two test methods have been compared extensively, in terms of: • Ability to measure the essential parameters, such as flame spread and heat release. • Discrimination (i.e. ability to discriminate cables, whatever their level of fire performance). It was found that while SBI does not enable the cables to be ranked in terms of flame spread, for other parameters (THR 600s , HRR peak , FIGRA, TSP), both methods can be adequate, even if for cables with very high fire performance (e.g. as required for installation in some hidden voids), more stringent scenario(s) might be needed. A number of possible pitfalls have been highlighted, for the future possible use of those methods for the harmonized classification of cables. |
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