The WaStop Inline check valve installs in stormwater systems and outlets, providing immediate protection against flooding and backflow. Its unique, simple, and effective design also prevents unwanted odour, especially at outlets in tidal environments. The standard variant is supplied with an EPDM gasket and mounting tabs. Technical specification Nominal diameter DN 525 (NPS 21) Max. Flow Velocity 4 m/s (13.1 fps) Weight 37 kg (81.6 lb) # Bolt holes (#B) 4 Bolt Circle Diameter (BCD) 678 mm (26.7 in) Dimension 515 mm (20.3 in) Valve body length (L) 1000 mm (39.4 in) Outer Ø (OD) 515 mm (20.3 in) OD incl. gasket (ODG) 543 mm (21.4 in) Ø Bolt Holes (ØB) 10.5 mm (0.4 in) Max. Flow Volume 833 l/s (13203.3 GPM) Max. ID Host Pipe 540 mm (21.3 in) Min. ID Host Pipe 518 mm (20.4 in) Fasteners mtrl. 316L stainless steel Gasket EPDM Product sheet (PDF) Technical specification (PDF) Dimensional drawing (PDF)