The Water Services Association of Australia (WSAA) has recently released a new product specification for casing spacers.
Casing spacers are used for the protection of carrier pipes when installed inside casings, and the new WSA PS- 324 Casing Spacers standard is the next step in ensuring that pipelines across the country are fitted with high quality spacer systems.
“There is now clarity when it comes to choosing the best spacer to ensure the longevity and success of the pipe installation,” said kwik-ZIP Spacers Managing Director, Jason Linaker.
“The release of this new standard means that if you are installing a water pipeline and fail to use the correct type of spacer for the carrier pipe, you are not complying with WSAA’s standard.
“Timber used as a spacer – which is still common for a surprisingly large number of contractors – is simply not compliant with the standard.
“Over time, timber will rot away leaving either gaps in the grouting, or if grouting wasn’t used, the pipe will move once the timber is no longer able to support the pipe.”
Mr Linaker said there is also the risk that timber will wear away as it is run in.
“Although spacers are usually a small part of the overall pipe installation process, correctly designed and fitted spacers can significantly increase the life expectancy of the carrier pipe by keeping it free from corrosion, casing damage and overall wear.
“A material like timber will not last in an environment with water, which is why the new standard requires casing spacers to be manufactured from inert materials.”
The new spacer specification
The requirements of spacer systems outlined by the new standard are as follows:
- Casing spacers shall be manufactured from inert engineering thermoplastics or stainless steel (Grade 304 or 316).
- Steel spacers shall not be used on metallic carrier pipes unless the spacer collar is coated or lined to prevent corrosion occurring at the point of contact between spacer and carrier pipe. The coating shall be inert so that it is compatible with metallic carrier pipe coatings.
- Casing spacers shall be designed at intervals that allow them to support the weight of the carrier pipe and its contents for the design life of the installation.
- If used inline in drinking water applications, the casing spacer shall comply with the requirements of AS/NZS 4020:2005.
- Spacer runners shall incorporate a wear pad manufactured from abrasion resistant material such as Acetal POM, Nylon, or HDPE.
- Casing spacers shall be complete with restraint from movement on the carrier pipe.
- The wear pads shall be bevelled to prevent jamming during insertion.
- Spacer runners shall be spaced radially around the pipe with a maximum angle between runners as follows: (i) Carrier pipe diameter up to DN 150: 90 deg. (ii) Carrier pipe diameter between DN 150 and DN 275: 75 deg. (iii) Carrier pipe greater than DN 275: not greater than 100 mm between runners at the inner circumference of the casing spacer. (iv) Runner height shall be sufficient to provide at least 10mm of clearance for the bells or couplings during insertion.