HDPE pipe as per IS:4984 & IS:14333 standards Polyethylene formed by the polymerization of ethylene, are tough, waxy materials of varying flexibility. For pipe applications, they are generally formulated to screen out ultraviolet radiation in sunlight. Polyethylene pipe products are protected against deterioration from exposure to ultraviolet light and weathering. Black pipes contains 2 to 3% carbon black to protect them from UV deterioration.