Ductile Iron Air Valves, Air Valves, Air Control Valves. Air Valve Body: ductile iron. Standard: DIN 3352/BS 5163/AWWA. Pressure: 150 to 2,500LB. Resilient gate valve PN10, PN16, PN25. Body/bonnet: cast iron/ductile iron. Wedge: cast iron/ductile iron with EPDM. Stem: stainless steel. Coating: epoxy painted with 200 microns.