Anti-siphon units are designed to prevent the release of foul air whilst admitting air under conditions of induced or self-siphonage in discharge pipes preventing water seals in traps from being drawn. The W50 is suitable for connection to 51mm Vulcathene pipe and incorporates a rubber seal which must rst be inserted into the pipe followed by the anti-siphon unit. The anti-siphon unit is approved to BS EN12380 (A11)
