Galvanised steel is all around, even when not visible. Many houses built before the 1960s are framed with it, and many buildings still use piping made from galvanised steel. This type of metal is inexpensive, durable, and resistant to corrosion, which makes it attractive to the construction industry. Plus, it can be reused and recycled, which makes it ideal for green projects. However, there are many disadvantages to using galvanised steel, and it is therefore gradually being replaced in most plumbing systems.
Galvanised steel is used primarily in the construction industry, and its primary applications include roofing, support beams and braces for walls, and piping. This type of metal, often used for heating and cooling duct work, safety barriers and handrails, is an essential material in automotive body parts. The reasons for its popularity include its strength and resistance to corrosion, which are both due to the protective layer of zinc added to the steel during the galvanisation process. Galvanised steel is unmatched in popularity for marine applications, as other materials are prone to rusting and therefore deteriorate rapidly.
Galvanised steel is steel that has been coated with zinc to prevent corrosion. The steel is submerged in hot, melted zinc, which triggers a chemical reaction that permanently bonds the zinc and steel together. During the galvanisation process, the steel is first exposed to zinc at a temperature of approximately 460 degrees C. The zinc reacts to available oxygen in the environment to form zinc oxide, which then forms zinc carbonate after reacting to carbon dioxide. Iron molecules in the steel react with the zinc, creating layers of metal that are able to withstand even long term contact with saltwater.
Because galvanised steel is coated with zinc, it offers many benefits over traditional steel or iron piping. The zinc coating drastically reduces corrosion and prevents minerals from depositing inside the pipe lines. In larger construction projects, such as sewer systems and farm irrigation, galvanised steel pipes are often the piping of choice and often remain in working order with little maintenance for 40 years or more. Galvanised steel is more flame resistant than PVC piping, and is stronger than aluminium piping. This type of metal also works well under freezing conditions.
In spite of its many benefits, galvanised steel is not always the ideal choice. When mixed with yellow brass, galvanised steel triggers dezincification, and it results in electrolytic action when combined with nonferrous metals, such as copper and brass. Galvanised steel should never be used underground unless properly covered, which can be inconvenient for many jobs, and it often hides significant defects beneath the zinc coating on the steel. Galvanised steel pipes may contain lead, which corrodes quickly and reduces the lifespan of the piping. Moreover, galvanised steel may leave rough patches inside pipes, resulting in serious failures and stoppages that can be expensive to repair. Because of these issues, most modern homes use copper piping as an alternative.
Galvanised steel and copper cannot be connected to each other as the two can produce a chemical reaction that weakens the joint. Because of this, it is crucial to use only one type of material in a system, especially for plumbing repairs. In older homes, galvanised steel also poses a risk due to its lead content, which has been proven to be unsafe for both children and adults. High levels of lead in drinking water has been linked to decreased intelligent, behaviour problems, and neurological conditions in children. If you suspect your family is at risk of lead poisoning caused by galvanised pipes, have your water tested to determine the levels of lead present, and get your children evaluated by a paediatrician as soon as possible. The World Health Organization states that all owners of homes built prior to 1970 are at risk and recommends having their water tested. The WHO also recommends that anyone living in an older home flush their taps by running cold water through their pipes each morning before drinking or cooking.