Solid Twinwall pipe is made from HDPE plastic and manufactured by a twin extrusion process whereby two layers are simultaneously extruded one inside the other and heat welded together in one continuous step. The solid outer wall is corrugated providing excellent structural strength which reduces the possibility of on-site damage and the inner wall has a smooth seamless finish to assist hydraulic flow. The design unlike traditional single-wall pipe prevents silt accumulation. Ideal for gravity surface water and stormwater drainage applications this plastic pipe is used for Highway filter and carrier drains, Rail Track Drainage, Golf Course Land Drainage, Catchpits and Land Reclamation projects. Complies to BBA, HAPAS Roads & Bridges.