Spacers, while only a small component, can provide significant benefits to the overall installation of a pipeline. Choosing the right spacer, made of the right material, is essential for getting the best results in a project.

kwik-ZIP Managing Director Jason Linaker says there are a number of factors to take into consideration when choosing the right spacer and having the right information will ensure that a project has the biggest chance of success.

“Although spacers are usually a small part of the overall pipe installation process, correctly designed and fitted spacers can significantly increase the pipeline’s life expectancy by keeping it free from corrosion, casing damage and overall wear,” says Mr Linaker.

Material matters

Spacers can be manufactured from a number of materials and the chosen material can impact on the longevity of the pipeline, as well as long-term costs.

The Water Services Association of Australia (WSAA) product specification for correct protection of carrier pipes when installed inside casings, WSA PS-324, is one source of information that contractors can refer to so that they can ensure the most appropriate product is used.

Mr Linaker says the standard outlines various requirements for the spacer, including use of materials, abrasion resistance, wear pads, runner height flexibility and minimum runner spacing around the pipe.

“While the specification is aimed at water pipeline installations, these elements are relevant to all pipeline installations where there is a carrier pipe, as they help to prevent problems experienced during these installations across the board, such as abrasion and achieving correct grade and alignment,” he says.

Getting the best results

Two commonly used spacer materials are timber and metal; however, while these may provide initial project cost savings, they do not comply with the WSAA specification, and could cost the asset owner more in the long term as they can have a negative effect on the longevity of the pipeline.

Metal spacers are commonly used in water and gas pipeline installations; however, they present several problems.

“Metallic spacers are prone to corrosion in installations where acid soil conditions, water or existing corrosion are present,” says Mr Linaker.

“When corrosion occurs it can breach the grout seal around the new pipe and be transferred via the metallic spacer to the pipeline itself, whether it’s made from steel or plastic. Metallic spacers also have a track record of damaging plastic pipes such as fibreglass or glass reinforced plastic.”

Makeshift timber spacers are also commonly used as a cheap alternative to other materials available.
While makeshift timber spacers may be more cost effective than other materials, there are long-term negative consequences for the durability of the pipeline that need to be considered.

“It is still surprisingly common for contractors to use makeshift timber spacers, which is concerning,” says Mr Linaker.
“Not only do these not meet the WSAA specification but they simply will not last the lifetime of the pipeline and could lead to costly maintenance or replacement.

“The problem with timer is that, over time, it rots away, leaving either gaps in the grouting, or if grouting isn’t used, the pipe will move once the timber is no longer able to support the weight. There is also the risk with timber that it will wear away as it is run in.

“Furthermore, a material like timber will not last in an environment where water is present, which is why the specification requires casing spacers to be manufactured from inert materials.”

Single system solution

Mr Linaker says when it comes to choosing a spacer system, selecting a non-metallic product made from high grade thermoplastic – like kwik-ZIP spacers – will make the installation easier and extend the life of an asset.

“kwik-ZIP spacers are made from Kwik-ZIP’s engineered thermoplastic blend – a high-grade thermoplastic that is flexible, extremely tough and has a low coefficient of friction, ensuring they are corrosive-free so they won’t transfer existing corrosion to the new pipe, and as they are resistant to installations involving water, including seawater, the spacers themselves will not corrode or rot.

“They are also the only product in Australia that is approved by WSAA against WSA PS-324,” he says.
The spacers also have a flexible design. This means the same product can be used across a project as various runner heights can be achieved, allowing for different pipe/casing combinations.

“Typically, spacers will be manufactured to fit a particular pipe diameter. This means that different sizes of spacers are required for different pipe diameters,” says Mr Linaker.

“kwik-ZIP spacers are designed to be adjustable, mean

“Because you only need one product group across the whole job site, this cuts down on confusion about which product to use where, and speeds up installation.”

The company’s spacers are also constructed with wear pads on the runners. This gives them a low friction coefficient, making it easy for the pipe/casing to be inserted without damaging it.

Article published in Trenchless Australasia Magazine September 2018