Right then. Had a look at a few websites. What appears below is from one forum and would seem to be accurate:
The stickers are required by law in the UK if you are transporting gas for work purposes only.
If its for personal use, e.g. no reward, then you are not required to use a sticker.
Knowing a few fireman though, they prefer it if people put the stickers up if they are carrying compressed gas, regardless of whether its for work or not. It makes things a damn site safer if you do have an accident, and cannot tell the fire brigade what you are carrying. If you aren't carrying gas though, but leave the sticker up, it delays rescue attempts.
We carry diving gas quite often, and have a compressed gas sign stuck to one of those "baby on board" sucker pad things. Lives in the car and is very easy to put up/remove.
Also, make sure your bottles are well secured. A 12l 232 bar cylinder (std dive tank) contains roughly the same energy as 2 hand grenades, and it the valve is knocked off will do some serious damage.
And, someone after my own heart, who likes to insert quotes from legislation:
I have checked the 'Carriage of dangerous goods' section of the UK Road Vehicles Construction and Use Regs.
As Storm Monkey has already said, "The carriage of dangerous goods by private individuals intended for their personal or domestic use or for their leisure or sporting activities." is an exception under the regulations.
However, for those of you who are in business the following should be noted:
"The regulations described below are complex and it is only possible to give an outline summary of the very detailed requirements. It is advisable for any operator to have complete copies of the regulations and the associated document — ADR — to ensure full compliance.
Note: There is no quantity of dangerous goods as defined by these regulations that is totally exempt from the requirements, this means that plumbers, builders and other tradesmen may be subject to the regulations. There are concessions for small quantities and certain transport operations (these are explained below)."
The above are direct quotes from C&U regs for information.
Also out of interest (boredom?) I took a look around a local caravan agent, and all new caravans in stock had the warning diamond on the gas bottle stowage locker. This does not appear to be required under the regulations, but is probably considered to be 'good practice'.
So there you have it.
- You are not required to display a "Compressed Gasses" sticker in your vehicle.
- If you have an accident, with compressed gasses in your vehicle, the emergency services would appreciate knowing.
- If you do display a warning, it may delay a response in event of an accident.
Get one that is easy to remove.
It is also worth noting, that most insurance companies will require you to inform them that you carry compressed gasses for recreational purposes. If you don't and you have an accident, they will use that fact to get out of paying. Most likely not caring if the compressed gas had any impact on the accident.
As for public transport. Who will know? Consider what you would do, if you had just been to the shops and had bought a Soda Stream or bottle of balloon helium. There is no mention of what pressure the gas is stored at, with regards to an upper or lower limit, it just states "compressed". This could easily refer to deodorant or squirty cream.
I did see mention elsewhere, that carrying anything over 200L of compressed gas, requires a License. I would imagine that this refers to the cylinder capacity and not the expanded volume of what is contained within it.