Advance Steel Tubes Ltd. Offers Zinc Coated Sewage Pipe. Advance Steel Tubes Ltd. Has been certified for ISO 9001:2000. Zinc Coated Sewage Pipe is suitable for all types of ground conditions and above ground applications, such as pumping stations and treatment works. Zinc Coated Sewage Pipe is available in full range of diameters and fittings, to suit different ground conditions and pressure ratings.