On 1 May 2015, Western Australia (WA) adopted the Plumbing Code of Australia (PCA) as the primary technical compliance standard for plumbing work.
Since that time, all plumbing work carried out in WA must comply with the Performance Requirements of the PCA and any modifications set out in regulation 49 of the Plumbers Licensing and Plumbing Standards Regulations 2000 (Plumbing Regulations).
A key change brought about by the implementation of the PCA was the introduction of ‘Performance Solutions’ as a way of achieving compliance with the Performance Requirements of the Code.
This has given hydraulic consultants and licensed plumbing contractors in WA the flexibility to develop more innovative approaches to plumbing work rather than having to stick rigidly to the relevant referenced Australian Standards.
The first time a plumbing Performance Solution was used in Western Australia was in mid-2015 when a vacuum drainage system was installed as part of the construction of the Perth Stadium.
A vacuum drainage system was chosen for the event level of the stadium (ground level) because the site is highly unstable ground where the installation of heavy wet wells was not an ideal solution. As the standards contained no Deemed-to-Satisfy Solutions for the vacuum system at the time, a Performance Solution was utilised.
Under WA’s Plumbing Regulations, the licensed plumbing contractor is required to submit a notice of intention for major plumbing work. If the proposed plumbing work includes a Performance Solution, a specific notice of intention together with verification must be submitted to the Plumbers Licensing Board (the Board) at least 5 working days prior to commencing the work. This provision has allowed the Board to know what Performance Solutions are being applied and to monitor those solutions during construction if required.
Since 2015, the Building and Energy Division of WA’s Department of Mines, Industry Regulation and Safety (Building and Energy) has received over 50 notices of intention to install Performance Solutions as part of major plumbing work.
These have ranged from large-scale solutions such as the one used at Perth Stadium, to relatively simple solutions such as an amendment to the Deemed-to-Satisfy requirements e.g. the relocation of the mandatory inspection opening at the base of a stack.
Proven Performance Solutions used in WA
Of the many Performance Solutions installed in WA to date, those proven to be especially useful are based on the British and European plumbing design standard, BS EN 12056 – 2:2000, Gravity drainage systems inside buildings.
These solutions are based on the principle that modern sanitary drainage systems now have reduced flows as a result of water saving measures. Although the international sanitary plumbing systems may differ in design, the flow rates from fixtures are similar to those in Australia. These types of Performance Solutions allow the size of a main drain to be reduced and may enable connection to an existing sewer connection that cannot be increased in size. This requires the hydraulic designer to calculate a revised size and grade, whilst still meeting the required liquid-to-air ratio and maintaining a cleansing velocity that will meet the Performance Requirements of the PCA.
Want to know more?
An information guide on the process for developing and notifying Performance Solutions in WA is available. This information includes a case study of a worked example of a Performance Solution using BS EN 12056 – 2:2000. This case study is located in Appendix D of the information guide.
The ABCB also produces resources to support developing Performance Solutions, available for download from the Resource Library.