Reversion Fittings For Multilayer Pipe Installations In Class 1 Buildings

Due to the volume of calls regarding the changes to AS/NZS 5601.1:2022 – Gas Installations, we have decided to go through each of the changes and elaborate on them individually.

MPAQ recommends you still consult AS/NZS 5601.1:2022 and read the clauses yourself.

Starting off this series of information snippets, we will be looking at Clause 4.3 (Table 4.2). Brazing, welding, or annealing shall be conducted in accordance with the manufacturer’s specifications, but shall not be less than 1m from a joint with non-metallic components. This includes consumer pipework external to a building which shall be metallic and extend at least 1m into a building. Also mentioned in Clause 5.3.16 - Multilayer pipe shall not be installed above ground external to a building.

Clause 5.2.12 provides guidance regarding reversion fittings for multilayer pipe installations in Class 1 Buildings.

If the main run exceeds 10m in length and is connected to more than one appliance, reversion to standard thread conforming to ISO 7.1, BSPT or a standard annealed copper tube, 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

Images from Elson

Clause 5.2.11 – Provision of fire emergency isolation for multilayer pipe also enters this discussion as we would also be required to install an excess flow valve if we were using multilayer pipe for an installation on a Class 1 building.

It is also worth mentioning that Copper press fittings also have non-metallic components in the form of an O-ring. The yellow O-rings in gas press fittings are made of Hydrogenated Nitrile Rubber (HNBR). They have a heat resistance of 70 to 150 Degrees Celsius. We will require approximate temperatures of 300 – 600 Degrees Celsius to braze fittings. As this temperature exceeds the heat resistance of the O-ring, we need to make sure any press fittings are also not within a meter of an appliance point or consumer pipework external to a building.

Why 1m? If someone replacing an appliance in the future were to braze a fitting close to the wall, a non-metallic fitting within a meter could become damaged and leak due to excessive heat. Copper is a good conductor of heat with thermal conductivity 20 times greater than stainless steel. This means that heat can easily travel up a pipe and damage non-metallic components.

On existing installations, if you have multilayer pipework coming out the external wall feeding a gas meter, regulator, or BBQ point, you are going to need to bring the installation inline with Clause 5.2.12 and Table 4.2.

The requirements for certifying compliance of all or part of a gas system installed are provided under S-734 of the Petroleum and Gas Act and S-95 of the Petroleum and Gas Regulation. The certificate requires the installer to certify that the gas system and any gas work complies with all relevant safety requirements. AS/NZS 5601.1:2022 is the safety requirement for installing and altering gas systems.

There is no easy way to achieve this on an existing installation as the multilayer pipe will generally be clipped to the timber frame behind the brickwork. The only was to access this is to remove multiple bricks to access the pipe and replace the final meter with metallic pipework. If you were to remove brickwork and alter the multilayer pipe installation, you would also be required to install an excess flow control valve to comply with Clause 5.2.11.

So, do you need to install an excess flow control valve when you issue a Gas Compliance Certificate on every installation with multilayer pipe? Maybe not but there are many different scenarios.

Note 4 of Clause 5.2.11 of AS/NZS 5601.1:2022 states that the clause does not apply to the replacement of a gas appliance on a multilayer pipe installation but it does apply if you alter or add to the consumer pipework on a multilayer pipe installation. If you replaced a gas appliance and didn’t alter the consumer multilayer pipework or add to it, Clause 5.2.11 would not apply. However, as Clause 5.2.11 is a safety measure, it would be advised that we recommend the installation of the excess flow control valve to the consumer.

Confused? Please feel free to reach out to the Technical Team at MPAQ on 07 3273 0800 to discuss further.