Materials used for Plumbing Copper Copper pipe is the most popular type of piping used in domestic hot and cold water systems. It is also used in domestic central heating systems. Copper is a good conductor of heat, it is also relatively easy to bend when cold. It will not corrode to any great extent. Copper connections can be easily soldered. Mild Steel Mild steel or black iron pipe as it is normally known is used in large scale industrial plumbing such as factories, schools and hospitals. Black iron pipes are generally much larger in diameter than copper pipes. They are joined by threaded fittings or by welding. The greatest disadvantage to black iron pipe is the fact that it will rust and corrode easily. Lead Sheet lead is used for a variety of different uses within the construction industry i.e.:Flashing round chimneys and dormer windows. Flashing round where a flue projects through the roof. Dressing round special window features. Lead valleys. Lead is no longer used in pipes as it can contaminate water and make it poisonous. Lead Flashing round chimneys and a lead roof. Dressing round special window features. Plastic pipe Plastic P.V.C. pipes are generally used as waste pipes from domestic sanitary ware. They can be used in sinks, bathrooms and also in underground drainage. Vent pipes are generally also P.V.C. Several new types of plastic pipe have recently become available for cold water systems although they have not become very popular as yet.