First Order Evaluation of Fire Hazard in a Room Due to the Burning of Poly(Vinyl Chloride) Products in a Plenum: Estimation of the Time Required to Establish an Untenable Atmosphere

A study has been made to investigate the hazard due to the presence of PVC products (wire coating, rigid conduit and flexible conduit) in a plenum, in a variety of scenarios. It has been found that the fire itself, even if it is of low toxic potency, will cause an untenable atmosphere by: (a) flashover conditions (b) generation of lethal concentrations of toxicants, both in the room of origin of the fire and in other rooms long before the toxicity of the smoke from the PVC products becomes of concern. In summary, this work has shown that PVC products contained behind fire- rated ceilings are of little concern as regards fire safety.