Working in the gas industry, appliances are required to constantly be reassessed, to ensure that they maintain a safe standard. I recently asked a Queensland Gas Inspectorate about a press fitting’s recommended temperature limit (this is the press fitting around the pipework fitting in a caravan – see futher information), who explained that “the fitting is only rated to 70 degrees Celsius”.
This made me realise that gas fitters must be aware not to install press fittings in direct sunlight or hot roof space, as the press fitting may leak.
The answer in the 2010 Standards AS/NZS5601.2:2010 Means of Compliance, guides installers to Table 5.1 “From outlet of cylinder regulator to appliances” for copper pipe the table only identifies alloy flared compression, capillary, junction in hard drawn tube, socket using expanding tool. There is no reference to Press-Fit (they are included in Table 4.1 of Part 1).
I have found that the standard doesn’t state that you cannot use them, and it also misses out that you can’t use hose and hose clamps to join the pipe either. If a person in Queensland wishes to use a press fitting, they would have to apply to the Chief Inspector under Section 7 of the regulations in advance. The Chief will not accept Section 7 as a means of addressing an identified/existing non-compliance with a preferred standard.
I do not believe at this time a sufficient risk assessment could be produced to support consideration of any such application.
How should pipework fittings be installed?
It is safe to assume that there is no evidence that press-fit style fittings are suitable for gas systems that are subject to continuous vibration, however this may change in the future.
Have you thought that press-fit systems could be considered to be a “proprietary piping systems” by some people, and as such have restrictions imposed on them by the manufacturer’s documentation and instructions?
Operating temperatures are limited to 70 degrees Celsius (not above ambient, actual temp) by manufacturers. In the new standard released last year AS/NZ5601-2-2013 – there is now a clear indication on the temperature limitations of a maximum of 70deg C, in Part 2 of AS/NZ5601-2013 it mentions you cannot use a compression fitting with a non-metallic olive. Additionally in all cases the press fit fittings are not approved for a mobile situation ie: a caravan.
The press fit fittings cannot withstand vibration, considering the Australian road conditions; it is no wonder why the fittings could vibrate apart, as compared to the smooth super highways found in Europe.
In summary regardless of the codes and standards, the press fit gas pipe connection system is not suitable for caravans or marine gas systems.
Why? Because the press fit fittings will eventually be vibrated-loose and could cause a catastrophic situation (gas leak, fire or a gas explosion). The ambient temperatures could exceed 70deg C, again causing the fitting to leak. The press fit fittings are not suitable to be installed in a mobile van or marine craft.
What are pipework fittings and press fittings?
Pipe fittings are made out of copper, steel, plastic, ABS or CPVS and are the means to connect two pipes together. Metal pipes are threaded which screw together to connect, while plastic pipes can be threaded or slip fit use sleeves that slip into one another (reference Kayne, R 2014). There are a number of sizes and styles which you can get to suit the style pipe, read more about the different types of pipe fittings here.