NEW LOW FIRE HAZARD VINYL WIRE AND CABLE COMPOUNDS

The material of choice of wire and cable coating compounds used indoors has traditionally been PVC. PVC was chosen mainly because of its good fire performance. More stringent fire safety standards will probably need to be applied in the 1990s. These will require improved fire performance from wire and cabel compounds, while maintaining adequate physical properties. This work presents some results of a study designed to develop a new family of experimental vinyl compounds adequate for such applications. This work avoided the use of excessive levels of fillers, which affect physical properties negatively. A variety of testing techniques was used to measure both physical properties and properties associated with fire safety. The latter were: flammability (by limiting oxygen index (LOI)), smoke obscuration (by NBS smoke and smoke-char), rate of heat and smoke release (by Ohio State University rate of heat release calorimeter (OSU-RHR)) and smoke by factor (by OSU-RHR). The experimental products generated by using these efficient flame-retardant and smoke-suppressant systems are associated with much lower fire hazard than the traditional products. In particular, at low incident fluxes, the rate of heat release has been decreased by an order of magnitude and the smoke factor by over 400 times. This work was carried out using fire testing procedures which have been shown to be relevant to full-scale fires (RHR). The results indicate that fire performance cannot be correlated a priori with the chemical composition of materials. © 1990.