Can I use Corzan CPVC in a plenum space?
In most commercial building, the area above the suspended ceiling is used as an air plenum. Model codes restrict the surface burning characteristics of the materials that can be installed in air plenums. Various tests are used to evaluate the surface burning characteristics of construction materials. The most common requirement is to restrict materials permitted within plenums to those meeting a 25/50 flame spread/smoke developed when tested in accordance with UL 723/ASTM E 84 (NFPA 255 and UBC 8-1). As a reference, asbestos cement has a 0/0 flame spread/smoke developed rating and red oak has a 100/100 flame spread/smoke developed rating. Southwest Research Institute has tested water-filled Corzan CPVC pipe and fittings in general accordance with UL 723/ASTM E 84 (NFPA 255 and UBC 8-1). The results of the testing show: 1/2″ water-filled Corzan CPVC pipe and fittings have a flame spread index of 0 and a smoke developed index of 20 (Reference Southwest Research report No. 01.04017.01.301
