FIRE PERFORMANCE CABLES
The dangers of fire would include the safety of people and the continuous functioning of electrical circuits required to maintain safety. In the case of electric cables their construction may need to address some or all of the following; fire survival, fire resistance, fire propagation, flame retardancy, smoke emission and toxicity.
Even if the electrical circuit was not the cause of a fire, the electric cable may very well be engulfed in a fire that has started elsewhere. Consequently the compounds that the cable is produced from should not contribute to the fire, help spread it, or emit gases during combustion that could harm people or damage equipment. Another aspect to consider is that the density of smoke generated in the event of a fire should not be sufficient to obscure emergency exit signs.
Most cable standards therefore include some kind of fire performance and testing requirements, but there are many in existence.
Fire Test Standards for Cables
Here are a selection of standards used in relation to fire tests for cables :-
- BS 6387 : Performance requirements for cables required to maintain circuit integrity under fire conditions.
- EN 50266 : Common test methods for cables under fire conditions - Test for vertical flame spread of vertically-mounted bunched wires or cables.
- EN 50267 : Common test methods for cables under fire conditions - Tests on gases evolved during combustion of materials from cables.
- EN 50200 : Method of test for resistance to fire of unprotected small cables for use in emergency circuits.
- BS 8434-1 : Methods of test for assessment of the fire integrity of electric cables. Test for unprotected small cables for use in emergency circuits. (EN 50200 with addition of water spray).
- BS 8434-2 : Methods of test for assessment of the fire integrity of electric cables. Test for unprotected small cables for use in emergency circuits. (EN 50200 with a 930°C flame and with water spray).
- IEC 60331 : Tests for electric cables under fire conditions.
- IEC 60332 : Tests on electric and optical fibre cables under fire conditions.
- IEC 60754 : Test on gases evolved during combustion of materials from cables.
- IEC 61034 : Measurement of smoke density of cables burning under defined conditions.