Using spacers to mitigate water pipeline corrosion

Corrosion in the water industry is a known problem for asset owners, costing Australia around $983 million per year. With aging infrastructure a major problem, it is important to consider the use of additional components such as spacers to manage corrosion and reduce costs when rehabilitating and installing new pipelines using trenchless methods.

The cost of corrosion to the water industry has been quantified in a number of reports, including Corrosion Challenges – Urban Water Industry by the Australasian Corrosion Association (ACA). It impacts many areas of the economy, and affects water distribution and sewerage collection pipework as well as infrastructure, including a wide-ranging list of assets owned and operated by urban and rural water utilities, industry, agricultural and domestic.

The ACA report found pipeline failure to be particularly important as the failure of a major pipe can affect the wider community due to disruptions from flooding, road closures and loss of trade. These costs have been estimated at around $91 million per year to the Australian urban water industry.

Conventionally, a reactive approach to maintenance has been taken, with pipes continually repaired until they fail and need to be replaced. However, a more proactive response to preventing the spread of corrosion is needed, especially for larger critical pipelines.

A proactive approach

According to Jason Linaker, Managing Director of kwik-ZIP, an appropriate spacer system is one of the tools that can be used on new and rehabilitated trenchless pipeline installations to proactively manage pipeline corrosion.

“Choosing an appropriate spacer system can help mitigate the effects of corrosion. Spacers made from inert materials such as kwik-ZIP’s Australian designed and manufactured HDX range of spacers, which are manufactured from Kwik-ZIP’s engineered thermoplastic blend – a high-grade thermoplastic that is flexible, extremely tough and has a low coefficient of friction. They are the ideal choice for pipeline installations as they are resistant to the effects of corrosion.”

This is particularly important in harsh environments where spacers made from other materials such as metal do not hold up as well.

“Some spacer materials are prone to corrosion when they are used in certain environments. For instance, some areas may have acid sulphate soils. A metallic spacer, including those made from stainless steel, would be subject to severe corrosion if it comes into contact with acid sulphate soils,” Mr Linaker said.

“While such corrosion can be transferred via the metallic spacer to the steel pipeline itself, inert non-metallic pipe spacers are resistant to such conditions.”

New pipes used in trenchless rehabilitation projects can also be vulnerable to corrosion if they are inserted into a corroded pipeline. Corrosion can transfer between the old and the new pipe if the new pipe is made from steel, or if metallic spacers are used. Even if the new pipe is not steel, corrosion can still breach the grout seal around it.

“Inert non-metallic spacers are ideal for such projects as they are resistant to the transfer of pre-existing corrosion, ensuring they remain intact throughout the life of the pipe,” Mr Linaker said.

“Although they are a small component of the overall solution, using an appropriate spacer can make a large difference in the overall success of pipeline installations and corrosion management.”

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