Fire Resistant Cables

By implementing the Construction Products Regulation (CPR), the European Union aims to standardise and classify cables according to their fire performance. Additional to fire resistant cables there are other applications, particularly those used for safety and emergency circuits; that must be able to maintain communication even when the cable is subjected to flames in specific conditions. The following are two kinds of fire-resistant tests in order to comply with CPR regulations:

IEC 60331-25:1999: Circuit integrity test for cables under fire conditions. The cable is exposed to a 750°C flame for a minimum of 90-minute period. Passed this time the flame is expected to be extinguished but the optical fibres must continue to be monitored for another 15 minutes. The test result will be considered compliant if the increase in fiber attenuation during the 105 minutes does not exceed the maximum specified by the manufacturer.

UNE-EN 50200:2007: This is a test performed on unprotected small span cables used in emergency circuits. The cable is subjected to a 830°C degree flame of for a minimum period of 30 minutes (PH30) and up to a maximum of 120 minutes (PH120). Along to the exposure the cable support structure is hammered, causing the fall of charred particles. The result of the test is compliant if the attenuation variation of each fiber does not exceed 1.0 dB for single-mode fiber and 2.0 dB for multimode fiber.

OPTRAL has a list of CPR Certified cables that successfully surpassed these tests, it includes metal armoured and dielectric cables. They can be found at CPR Cables fire resistant (optral.com)