A cone calorimeter test for the measurement of flammability properties of insulated wire

We have investigated the use of the cone calorimeter to measure flammability properties of small diameter wires. Several different lest protocols were evaluated and one had the advantages of bring simple, effective and repeatable. Four commercially available wires were tested using this protocol. Parameters measured were: total heat release, peak heat release rate, total smoke, peak smoke production rate, peak carbon monoxide production and time to ignition. Three of the wires were flame retarded with metal hydroxide based halogen-free systems; the key difference between these wires was insulation wall thickness (thin, medium and thick). The fourth wire was insulated with chlorinated polyethylene (CPE) which contained antimony trioxide to improve flame retardancy, and was of medium wall thickness. The results demonstrate the negative impact on smoke and CO production of the CPE/Sb FR insulation versus the equivalent thickness halogen-free system. The tests also show how increased wall thickness adversely affects fin properties even when all the products are halogen-free. (C) 1999 Elsevier Science Ltd. All rights reserved.