Quite a few expedition campers are equipped with diesel powered cooktops, which I did consider, but given that we have no real intention of traveling outside of Australia with our truck, using LPG for cooking seemed like the logical choice for us.
When designing the subframe I figured that the best location for the gas bottles would be between the entry stairs and the truck’s batteries.
I started fabricating the base of the gas bottle frame, then I had a thought… will locating the gas bottles there be legal?
I decided to stop work on the gas bottle frame and instead I tracked down a copy of the Australian Standards 5601, which covers gas installations. As with so many of these types of documents, they are quite convoluted and cover way more than I was interested in.
After reading what I thought were the relevant pages it looked like everything would be okay, but given that all gas installations require certification by a licensed gas fitter, I figured that it would be prudent to confirm that what I wanted to do would meet all of the required regulations.
I spent quite a bit of time ringing around trying to locate a gas fitter that was licensed to do mobile installations. The guy I ended up choosing was very helpful and he confirmed that what I wanted to do would be legal and that he would have no problem certifying my gas installation, when completed. Getting this confirmation was a definite relief, as trying to change my overall design layout now would have been a real pain.
Like many other aspects of this project, building stuff isn’t really all that difficult; coming up with viable designs however… that’s the challenge.
It would have been so much easier to use one 9Kg gas bottle, opposed to using two 4.5Kg bottles, but I did not want to do that.
The reason for having two bottles is simple. You can be using one and always have a full spare bottle at hand.
Fitting two bottles into the available space was not the issue, it was designing a bracketing system that would allow easy removal of the bottles that was difficult. A standard hinged gas bottle bracket would not work because it would not be possible to open the clasp wide enough to get the bottles out. A “drop in” style bracket was not really suitable either, as it would have made it awkward to remove the rear bottle. The design I ended up with is not perfect, as it has removable parts, but it does work quite nicely.
The base frame is made from 40mm x 5mm angle and the securing brackets are all made from 32mm x 5mm flat bar. Using a sheet roller I bent these to the diameter of the gas bottles, then cut them to size. I also fabricated some custom hooks and clasps from stainless steel and used two standard over centre clasps to secure the bottles. All of the stainless parts are screwed to the brackets using countersunk head M5 screws. The bracket is secured to the base frame with three M8 bolts. Bolting, opposed to welding, allows for easy fitting of the stainless steel sheet on the base. The gas bottle frame utilises the steps frame on one side and the battery frame on the other to mount it to the subframe.
Another stainless sheet will be placed between the gas bottle frame and the battery frame to act as a physical barrier between the two. This is a requirement for certification, as the batteries are considered to be an ignition source.
I need to get the brackets and frame sandblasted, then I can paint them all. After being painted the inside of the gas bottle brackets will be fitted with 30mm x 3mm rubber. This will secure the bottles better and help with vibration. It will also help protect the paint on the bottles.
On the bottom rim of the bottles I will also fit some pinchweld. This will give some protection to the stainless steel base sheet and will also aid with vibration absorption.
The LPG gas bottles will be used for the cooktop inside the camper and for a pull-out BBQ, that will be located directly behind the rear wheel on the passenger’s side. In a future article I will cover the building of the BBQ and plumbing up all of the gas lines.
Update – 13 June 2012
Below are some images of the finished LPG bottle installation.
Update – 30 August 2012
For anyone that is interested, I have added a download link for the Australian Gas Installations standards (AS 5601-2004)
There is a newer version of this standards document (2010), but the content is pretty much the same. The main change to this document is that domestic and mobile installations have been separated into their own publications; AS5601.1 (domestic) and AS5601.2 (mobile).
You normally have to pay for these standards documents, but here you can get a copy of mine for free! Enjoy…
AS 5601-2004 ~ Gas Installations