Reversion fittings for proprietary multilayer piping

This advisory note outlines the updated requirements for installing reversion fittings in proprietary multilayer piping systems in Class 1 buildings. 
 

Last updated: 06 March 2025

On this page
Note:3/2025
Date issued:17 February 2025
Last updated:5 March 2025
For:Licensees and contractors working in the gasfitting industry
Issued by:Building Commission NSW Gas Compliance Unit
Scope:Applies to all areas in New South Wales

Purpose

The purpose of this advisory note is to inform licensees and contractors in the gasfitting industry about the updated requirements for installing reversion fittings in proprietary multilayer piping systems in New South Wales. These updates ensure that gas installations comply with AS/NZS5601.1:2022, enhancing safety by specifying the conditions and locations for reversion fittings in Class 1 buildings.

Issue

Amendment 2 of AS/NZS5601.1 has been released on 6 September 2024 (AS/NZS5601.1:2022) and becomes the referenced standard from 6 March 2025. 

Amendment 2 of AS/NZS5601.1:2022 still requires the reversion fittings installation and provides some additional requirements regarding the installation of the consumer gas pipework.

All gas installations in NSW must comply with the Gas and Electricity (Consumer Safety) Act 2018. 
Any installation not conforming to AS/NZS 5601.1:2022 is considered non-compliant.

Reference

Gas and Electricity (Consumer Safety) Act 2018

AS 5601.1:2022 - Gas Installations 

5.2.12 Reversion fittings for proprietary multilayer piping 

In installations in Class 1 buildings in Australia or detached or multi-unit dwellings in New Zealand, where a proprietary multilayer piping system having a main run exceeding 10m in length and connected to more than one appliance is being installed, reversion to standard thread conforming to AS ISO 7.1, BSPT, or a standard annealed copper tube, shall be provided at both of the following accessible locations: 

  • In the main run immediately prior to the first branch take off point.
  • In the main run immediately prior to the last branch take off point.

Brazing, welding or annealing shall be conducted in accordance with the manufacturer’s specifications, but shall be not be less than 1 metre from a joint with non-metallic components. 

Consumer piping external to the building shall be metallic and extend at least 1 metre into the building. 

Note 1: An example is shown in Figure 5.2.12(a).

Diagram illustrating gas piping within a house, showing the gas meter, metallic pipe connections, dropper pipes, and transition fittings. Labels indicate points of entry into walls and guidelines for pipe placement.
Figure 5.2.12(a) - Example of reversion fittings in a multilayer piping system (composite pipe).

Note 2: Figure 5.2.12(b) and Figure 5.2.12(c) show acceptable reversion options for conformance to this Clause.

Technical diagram of a multilayer piping system with reversion fittings. It includes a copper-to-multilayer pipe transition, brass barrel union, and standard thread reversion connectors.
Figure 5.2.12(b) and (c) - Multilayer piping system - acceptable reversion fittings.

Note 3: The reversion fitting may be incorporated in the upstream side of the branch take off fitting.

Note 4: The intent is to allow for future extension or connection to a non-compatible piping system to protect the consumer/end user from difficulties that may arise from non-availability of the proprietary system.

Note 5: For definition of Class 1 building, see the National Construction Code (NCC).

Relevant definitions

AS5601.1 2022

1.3.1 - Accessible 

Access can be gained without hazard or undue difficulty for inspection, repair, testing, renewal, or operational purposes. 

1.3.86 - Permanent joint 

Joint that is not intended to, and cannot readily, be disassembled.

Examples of permanent joints are brazed, welded, crimped and hydraulically or mechanically compressed joints. 

National Construction Code (NCC)

Class 1 buildings

Class 1 buildings are houses. Typically, they are standalone single dwellings of a domestic or residential nature. 

A Class 1 building includes one or more of the following sub-classifications: 

  1. Class 1a is one or more buildings, which together form a single dwelling including the following:
    • a detached house; or
    • one of a group of two or more attached dwellings, each being a building, separated by a fire-resisting wall, including a row house, terrace house, town house or villa unit.
  2. Class 1b is one or more buildings which together constitute
    • a boarding house, guest house, hostel or the like that:
      • would ordinarily accommodate not more than 12 people; and
      • have a total area of all floors not more than 300 m2 (measured over the   enclosing walls of the building or buildings); or
    • four or more single dwellings located on one allotment and used for short-term holiday accommodation.

Requirements

As required in Clause 5.2.12 (above), you must install a reversion fitting when: 

  1. Installing a proprietary multilayer piping system in a Class 1 building and,
  2. Where the proprietary multilayer piping system has a main run exceeding 10 metres in length and,
  3. More than one appliance to be installed. 

A reversion fitting shall be provided at both of the following accessible locations: 

  1. In the main run immediately prior to the first branch take off point.
  2. In the main run immediately prior to the last branch take off point. 

Building Commission consider the following example diagrams below to meet the requirements of AS/NZS 5601.1 2022: Clause 5.2.12

Example 1

The reversion fitting installed using permanent joints in a wall or ceiling, the same size as main line in an accessible location. If the reversion fitting is installed using a union, screwed fitting or similar non-permanent joint, the wall or ceiling also needs to be ventilated as per the ventilation requirements prescribed in AS/NZS 5601.1 2022 

Schematic diagram of a gasfitting system, highlighting accessible reversion fittings installed in ceiling joists. Components include a gas meter, room heater, cooktop, hot water heater, and BBQ.

 

Example 2 

Reversion fitting, the same size as the main line can be extended to the accessible roof space. If the reversion fitting is installed using a union, screwed fitting or similar non-permanent joint, the roof space will also need to be ventilated as per the ventilation requirements found in AS/NZS 5601.1 2022. 

Gasfitting schematic with reversion fittings extended to accessible roof space. The diagram labels capped points, cooktop, hot water heater, room heater, and BBQ connections.

 

Example 3

Reversion fitting extended to external wall. The pipework extending the reversion fitting must remain the same size as the main line to the capped point installed in an accessible location. Capped point must have a sign stating, 'Gas Reversion Fitting'. 

Gasfitting system diagram showing reversion fittings extended externally to the building and capped. Labels indicate key gas appliances, including the cooktop, hot water heater, and room heater.

In addition to the above reversion fitting requirements, the gas consumer piping shall be installed in accordance with AS/NZS 5601.1 2022 – Table 4.2, referencing the applicable pipe material being installed. 

The transition fittings referenced in Figure 5.2.12(a) shall be installed referring to Table 4.2 and Clause 5.3.8 (Piping in a concealed location other than underground or embedded in concrete) and be a permanent joint when installed inaccessible in a cavity wall. 

Brazing, welding or annealing shall be conducted in accordance with the manufacturer’s specifications but shall be not less than 1 metre from a joint with non-metallic components. 

Consumer piping external to the building shall be metallic and extend at least 1 metre into the building. 

Consumer piping prior to exiting a wall shall be metallic for at least 1 metre. 

Contact Building Specialist Compliance Unit (BSCU)

This advisory note has been approved for issue by the BSCU Technical Review Committee. Information contained within this document is current as of February 2025 and refers to codes and standards current at the time of writing. 

Building Commission NSW disclaims any liability (including for negligence) to any person in respect of anything done, or not done, by that person in whole or partial reliance on any of the information in this advisory note.

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