Firstly the disclaimer ! I am not a lawyer, and the following should not be taken as legal advice. This is simply a statement of what I believe the legal position is at the moment.

There are several related things to consider, both for a ‘professional’ conversion and for a DIY conversion - the law, safety, and insurance.

The law doesn’t actually have much to say, unlike gas installations in buildings there is no legal requirement to be a member of any body, nor to hold any form of certification. That is not to say that there are no laws covering a conversion, I’m fairly certain that some of the construction and use regulations could cover unsafe conversions.

There is a trade body, the LP Gas Association who cover vehicle installations along with many other areas. I have mixed feelings about them, on the upside they do some good works in setting standards, on the downside I do feel that they are ‘a bit protectionist’ and would be quite happy if LPGA membership was made a legal requirement. Certainly in the past, when I’ve been ringing round to buy kit for my own conversions, I’ve been told the same untrue statements from a number of different LPGA members - and the only way I can see that happening is if the LPGA tell their members these untrue ‘facts’. Incidentally, I looked at their membership requirements and costs, it works out at over £100/year minimum - based on over £500 in fees to join, and after 5 years you have to go through the whole inspection again.

The standards normally worked to for vehicles installations are the LPGA Code of Practice No 11 - Autogas Installations (referred to as just CoP11 for convenience). This is quite detailed (20-something pages) and lays down a whole raft of requirements - some of them need a bit of thought, some are just common sense, and some you probably wouldn’t guess. In a lot of cases though, all you need to do is pick the right gear and the requirements are taken care of - a couple of examples :

Filler - this must be mounted so that it will take a 500 newton (about 50kg) force on the hose, which is the pull required to operate the breakaway coupling you’ll find in all forecourt filling hoses. You can either do some sums yourself, or just use a mounting kit that’s been designed by the manufacturer to meet that requirement. As an aside, you then wonder about the strength of some of the panels you see fillers attached to - but the structural strength of the vehicle isn’t covered by CoP11.

Multiple tanks - when more than one tank is fitted, there must be non-return valves in the liquid lines to prevent one tank emptying into another as this could allow the tank to be overfilled. You can go to the trouble of fitting some valves (it’s all extra work), or simply use tank fittings that include a non-return valve as standard. The multivalves I use include these non return valves, electrical shutoff, manual shutoff, and excess flow protection - all in one unit so that’s a whole list of requirements taken care of automatically.

Note: There is a European Standard for LPG components (ECE 67.01), and this is specifically referenced by CoP11. In general, if the component is marked as complying with E67.01 then it should be OK, if not then you will have to demonstrate that it meets the equivalent standard - so just stick with approved components.

So, we’ve decided that it’s legal, and we’re following CoP11 so it’s safe - the next thing to consider is insurance. Although it’s covered last here, you ought to consider it first as different insurance companies have very different attitudes. Some insurers simply will not cover converted vehicles - my opinion of what this says about their understanding of risk is probably best left off the written page ! Some will insist that the work is done and certified by an LPGA member. More normally, they will require a certificate to show that the installation is safe - and this is where it can get tricky with a DIY installation.

Now I’m OK, I’ve been on a course and have a certificate to say that I am, in the vernacular used in CoP11, a “competent person” - ie “a person with knowledge, training and ability to carry out their work safely and with the necessary proficiency to ensure the subsequent safe operation of the vehicle.” This means I can write my own certificate and certify that my own work meets the standards - does anyone spot the flaw in that ? Yes, whether it’s just someone who’s done a course, or an LPGA member, the person certifying the work is the one that did it - and of course you are going to fail your own work aren’t you ! And did I mention that the LPGA would like to make this a closed shop so that ONLY a full LPGA member can do the work or write certificates.

If you are fitting your own conversion then you have a few options, but it would be wise to sort this out before you start.

First option is to find that your insurance company will insure you without a certificate. Yeah, and there’s a porcine aerobatics display team just passing my window ! I don’t think any insurance companies will do that now, but some did when I converted my Disco - they accepted it being done with a “kit” and following the supplied instructions.

The next option is simply to go on a course, get to use the trainers workshop, and do the conversion while there are experienced people about - and if it’s a distributor like we used, a warehouse full of materials should something unforeseen crop up. Since the courses are normally for two (or maybe three) people, you get a mate to chip in a bit and then two of you have your certificates to say you are a “competent person”. In our case, it was a mates vehicle we were doing and it didn’t cost much more than buying the kit at retail - but now we have access to kit at trade, and access to their support when we need it.

The last option is to find someone that will supervise the job, or at least inspect it, and write you a certificate - good luck ! In my experience, don’t even bother asking an LPGA member, you are likely to be told that it’s illegal (it isn’t). If you do know someone who’s been and got a ticket, then you can ask them - but don’t be tempted to just turn up with a completed job and expect them to write you a certificate. The response from me to someone I didn’t know, and wasn’t expecting, would involved two words, and the second would be off ! But if the person knows you, and is satisfied that you are likely to manage the job safely, then there’s a good chance that they’ll do you a certificate when it’s finished - they’ll probably want to see some bits before they go on as it can be impossible to read information (such as serial numbers and test dates on tanks) once parts are installed. And of course, by discussing the job with them beforehand, they will be able to guide you so that when it’s done it actually does comply with standards.