\ v Hart&Cooley. SUBMITTER DRAWING install confidence WIRE HELIX FEATURES Two tough plies consisting of a layer of metabolized polyester and a layer of clear polyester encapsulating a steel wire helix creating a high strength and durable product. *Rated pressures (UL—181): 16 in. W.C. positive, 1 in. W.C. negative & 1/2” W.C. negative *Recommended maximum operating pressures (ADC Test FD 72-R1): 6 in. w.g. positive for 12 in. diameter and under. 4 in. w.g. positive for 14 in. diameter and over.