Branching pipes, not of metal; non-metallic air pipes for building; non-metallic insulated pipes for water; non-metallic pipes for building purposes; non-metallic pre-insulated bonded pipes for building; non-metallic rigid pipes; non-metallic rigid pipes for construction purposes; non-metallic water fittings incorporating flow control; non-metallic water pipes (other than parts of sanitary installations); plastic pipes (rigid) for water; rigid non-metallic pipes for building (other than parts of sanitary installations), rigid pipes (not of metal); rigid pipes not of metal (building); rigid pipes of plastics (other than parts of sanitary installations); underwater rigid pipelines, not of metal; water-pipes, not of metal