Whb-1 Mcalpine Wash Hand Basin Self Closing Valve Hand Wash Basin

Designed to allow full use of storage space below the basin within the cabinet or furniture. The internal membrane opens under water pressure to allow discharge to flow freely and then closes to form a seal to prevent foul odour or sewer gas entering the building. The valve allows air to be drawn into the discharge waste pipe when negative pressures occur and eliminates the need for secondary ventilation to the discharge pipework. This allows for greater flexibility in the plumbing design.