Black Square Engineering often designs tanks and pressure vessels for use with dangerous goods. We also do a lot of vehicle modifications (light vehicles, heavy vehicles, trailers, we’ve done it all). Less often, we are asked to develop a safe and innovative design for a heavy vehicle carrying four separate dangerous goods used in a ground breaking onboard process. I can’t tell you more than that, we’ve been sworn to secrecy. But it is really cool!
This post will talk about some of the challenges of taking a dangerous goods vehicle from concept onto the road. Actually, it is easier to start at the end of the approval process and work backwards.
In Queensland, the design of dangerous vehicles must be approved by the Department of Transport and Main Roads. DTMR’s website calls the process “Dangerous goods tank design applications”. Don’t be complacent, it means the whole vehicle. DTMR requires a statement of compliance to every clause of the relevant standard(s) in the “AS 2809 Road tank vehicles for dangerous goods” series signed by a Registered Professional Engineer of Queensland (RPEQ) with supporting evidence. There is not a lot of “wriggle room” in this process.
AS 2809 Road tank vehicles for dangerous goods has the following sections (document dates are correct at the time of writing):
Parts 1 and 2 are being reviewed with drafts presently available from SAI Global.
In our recent project we primarily used parts 1 and 4, so I’ll focus on them. Part 1 has the content you’d expect. For example: stability angles, road clearance, cabin-to-tank clearance (keep an eye on this one), drive away protection and, usually neglected, maintenance requirements.
Part 4 is where it gets tricky. AS 2809.4 is structured a bit like a cookbook: for a Type 1 tank you will use this design pressure, one of these materials and then engineering analysis to determine your wall thickness, nozzle geometry, etc. But when do you use a type 1, 2, 3, 4 or 5 tank? From section 1.1 of AS 2809.4: 2017:
“The 6th edition of the ADG Code makes the link between cargo type and tank type. In the context of this Standard, and aside from identifying the tank type, the latest version of the ADG Code should be used for all other purposes.”
This clarification is absent in previous editions of AS 2809.4 – you can spend a lot of time trying to research where the tank types come from if you are using an older version of the standard (personal experience).
So where to get the 6th Edition of the Australian Goods Code? It is almost prehistoric, being written in 1998. This was a problem that I had some trouble with, DTMR don’t keep it anymore and the National Transport Commission only had Volume 1 of 2 (being a good citizen, I sent them Volume 2 for their records).
Fortunately, one of our friendly industry peers at Holmwood had a copy and was kind enough to send it onwards. You know who you are and thanks for it, much appreciated.
Having found the required tank type by looking up the UN number of your specific chemical in Volume 2, the rest of the design process is straight forwards.
A few other things to consider:
Stay within the stipulations of ‘body builder’s manual’ for the truck body that you are building your dangerous goods vehicle on.
Always read the requirements of the current edition of the ADG Code.
Make contact with DTMR’s compliance people early in the process, especially if doing something innovative or out of the ordinary, they want to help.
Vehicles need approval for all states in which they will operate. If the vehicle will be operating outside of Queensland, make this known in the application.
Certain states require extra safety systems to be installed. For example a roll stability system is mandatory on all dangerous goods tank trailers in New South Wales.
Black Square Engineering can assist with your mechanical, electrical and structural engineering needs.
If you need a copy of the 6th Edition of the Australian Dangerous Goods Code or require any assistance with your project, please do not hesitate to contact Black Square Engineering we will be happy to assist.