Channa, I'm not sure how much read-across there is between a static installation and that in a vehicle..
You may be technically correct in saying that just closing the appliance isolation valves is considered sufficient. My van has three of them. Is that the same as a single ECV ?
An ECV is for use in emergencies. Not routine use. It's there for if e.g. a house catches fire and the firefighters need to go in. They'll turn it off first.
I am not au-fait with every applicable regulation throughout the EU, merely conscious of the dangers inherent in vehicle LPG systems, which appear to me to me to be mostly at the high pressure side. In boats the dangers are more acute and strictly regulated, they don't have drop vents.
Properly isolating ones gas supply before setting off is at the very least just prudence. It may possibly be a legal requirement in some countries, I don't know. Certainly Truma imply that their Monocontrol regulator which incorporates an impact sensor is required when using gas whilst in motion. Together with their special pigtails which incorporate excess flow valves at the cylinder end which have to be manually re-set if triggered. Perhaps that is so in Germany for example ?
Eurotunnel prohibit LPG powered vehicles, doubtless for their own good reasons. After all they've had at least two major fires down there. An underslung LPG tank is little different from an LPG vehicle installation. These things are vulnerable to damage, being underslung, and AFAIK not subject to any official testing regime in the UK. Anyone can buy the bits and have a go at fitting them themselves, it's encouraged by the suppliers. I'd like to think that they would have done their research first and do it properly, but who knows ? AFAIK they do not include an excess flow valve either. If they get ripped off, or just fall off what happens ? Even just go rusty on the outside, compromising their integrity.
Then I've seen them placed in an area that can get very hot. Autosleeper do this, it is about the only location available on a Ducato. Do these things have pressure relief valves to blow off below 30 bar like regular cylinders ? That's 435 psi by the way an immense pressure for such a thing. You'll hit that once the tank gets above 60C.
I do know that in Germany for example vehicles are subject to annual gas inspections. As was my static caravan, if only for
insurance purposes. Even the regulator was checked over various parameters and recorded on the certificate. Yet these are fit-and-forget items on campervans.
When looking into diesel hobs I found reference on a Finnish manufacturer's website referring to restrictions on parking in their cities when using vans with gas installations, that can be avoided by using a pure diesel setup. That makes sense.
To summarise: The OP asked a sensible question. I digressed admittedly. I still think that any vehicle gas installation should have a readily accessible way of isolating the supply as close to the source as possible, and be in the habit of using it. In my case it's simple, reach into the locker and turn off the bottle. With an underslung tank solenoid valves are available, not particularly expensive, and would give peace of mind.
The last Autosleeper that I looked at appeared to have a complete installation by Gasit, tidily done. I'd be surprised if it didn't have a solenoid valve at the tank, but perhaps not.
If I could eliminate gas from my van I'd do so but that's not practical. It's so convenient. Nevertheless I treat it with great caution. Others seem to be more casual, perhaps not fully understanding the dangers.
