Kimplas Piping Systems Ltd. Manufactures Medium Density Polyethylene Pipes. Kimplas Piping Systems Ltd. Also offers Pipes, fittings, valves, tools Medium Density Polyethylene Pipes are available in blue and black colors and have a pressure rating of PN6 to PN16. The Medium Density Polyethylene Pipes are BS: 6920 and WRAS, UK compliant. The Medium Density Polyethylene Pipes are used for water supply and are available in sizes ranging from 20 mm to 315 mm outer diameter.