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 test protocols were evaluated and one particular protocol had the advantages of being simple, effective and repeatable. Five commercially available wires were tested using this protocol. Parameters measured were: total heat release, peak heat release rate, total smoke production, 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. The fourth wire was flame retarded with an organo-chlorine/antimony trioxide system and was of medium wall thickness. The fifth wire was also of medium wall thickness and was insulated with a chlorinated polyethylene which contained antimony oxide as a flame retardant. The results demonstrate the negative impact on smoke and CO production of a Cl/Sb FR insulation versus a similar thickness of a halogen-free system. The tests also show how increased wall thickness adversely affects fire properties even when all the products are halogen-free.