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NCC 2022 Standards Spotlight: Plumbing and Drainage – Water Services

July 4, 2023

We continue our standards spotlight series with a look at AS/NZS 3500: 1: 2021: Plumbing and Drainage, Part 1: Water Services.

To see the other parts of our series, click on the relevant links: Part 1 – Emergency lighting and exit signs for buildings, Part 2 – Fire hydrant installations.


What is AS/NZS 3500: 1: 2021?

The AS/NZS 3500 series of plumbing and drainage standards play an integral part in setting out design and installation requirements for plumbing and drainage systems both in Australia and New Zealand.

AS/NZS 3500: 1: 2021 specifies requirements for the design, installation and commissioning of cold water services from a point of connection to the points of discharge. It applies to new installations as well as alterations, additions, and repairs to existing installations.

This standard is to be read in conjunction with:  

  • Volume Three of the National Construction Code (NCC), also known as the Plumbing Code of Australia (PCA); and
  • The New Zealand Building Code

Who is this standard for?

The primary users of the standard are plumbers and hydraulic designers. Other users could include plumbing regulators, residential and commercial builders, building designers, building certifiers, project managers, manufacturers, and testing authorities.

What’s changed for NCC 2022?

The latest version of the standard supersedes AS/NZS 3500.1:2018.

The revision to the standard aims to provide solutions to common problems faced by plumbers on site in their daily work, from installing pipes in bathrooms near other types of gas or electrical piping, to specific requirements for installing pipes in steel-framed dwellings.

Summary of key changes

New spacing requirements between water and electrical works to help promote better safety conditions:  

  • A separation of at least 25 mm shall now be maintained between any above-ground water service (a) Electrical or telecommunications conduits. (b) Electrical or telecommunications wires or cables. (c) Consumer gas pipes. (d) Sanitary plumbing and drainage. (e) Storm water drainage. (f) Other above-ground water services. (g) Any other service. There are also spacing requirements for any underground water service pipe and an electrical supply cable.

Maximum size limit on metal wall framework holes where water piping is passed through:

  • The revisions now state that for metal wall framework, water services shall be installed in existing preformed holes where possible. Additional holes, where required, shall be no larger than the preformed holes installed by the manufacturer, or 32 mm when there are no pre-existing holes.

The goal of this revision is to help ensure greater structural integrity and to keep up- to to-date with the technology being used.

Other important changes:

  • Conformance to individual product standards have been removed.
  • Definitions have been relocated to AS/NZS 3500.0.
  • The backflow hazard ratings have been removed from AS/NZS 3500.1 and are now only listed in the PCA.  
  • Jointing requirements for plastics pipes have been clarified and expanded to allow different methods.
  • The requirements for the marking of pipes in commercial buildings has changed to assist identification of pipework and avoid cross connections.  
  • The requirements for the installation of water services located in metal framed walls has changed to bring the provisions in line with those of the National Association of Steel-Framed Housing standards.

AS/NZS 3500: 1: 2021, Plumbing and Drainage, Part 1: Water Services is available via the Standards Australia Store and our distribution partners.

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