Materials for use in fire risk areas

PVC when burnt emits large quantities of dense black smoke and acid gas, and in addition to the debilitating effect of smoke and toxic fume inhalation, obscuration of fire safety exits delays or prevents escape. Improved PVC formulations producing less smoke and acid gas have been developed but still do not satisfy required emission levels. The demand therefore has been for materials to replace PVC which do not give off smoke and toxic fumes and do not contain halogens. The author describes how cable materials for fire risk areas need to have the following characteristics: (a) fire retardant and zero halogen; (b) low emission of smoke, toxic fumes and acid gases during combustion; (c) similar mechanical and electrical properties to PVC; (d) acceptable processability; and (e) low additional cost