Thread: Carrying an LPG bottle on roof rack

thanks

Anaconda has not long opend shops in SA, have not had a look at them yet.

have only been able to get 9kg ones for caravans

The cylinder must be mounted upright so that the relief valve is in communication with the vapour space. The relief valve flow rate is not adequate to accommodate liquid discharge and maintain the pressure at a safe level.
By having the relief valve attempt to handle liquid discharge you are open to the potential of a BLEVE ( Boiling Liquid Expanding Liquid Explosion) & contrary to popular belief this phenomenon is not restricted to flammable/combustible fluids.

Originally Posted by Aaron IIA

If it leaked a litre of gas, you would still have a litre of gas. If it leaked a litre of liquid propane, you would have 270 litres of gaseous propane.
Aaron

More too the point, if you safely discharged 1 litre of liquid, giving 270 litres of vapour, you potentially have some 14000 litres of flammable vapour. LEL - (Lower Explosive Limit) of LPGas is approx 1,9%

Originally Posted by Collins

By having the relief valve attempt to handle liquid discharge you are open to the potential of a BLEVE ( Boiling Liquid Expanding Liquid Explosion) & contrary to popular belief this phenomenon is not restricted to flammable/combustible fluids.

Not correct. Firstly BLEVE stands for "Boiling Liquid Expanding Vapour Explosion"

A BLEVE is caused when a leaky cyl has caught fire. A full bottle on fire is fairly safe as the liquid inside keeps the cyl cool.

However, as the level drops the uncooled steel starts getting hot from the fire and we all know what happens when steel is hot.

Eventually it gets too hot to be able to hold the pressure and it ruptures causing a massive explosion.

Here is a utube of a BLEVE.

[ame]https://www.youtube.com/watch?v=UM0jtD_OWLU[/ame]

Originally Posted by d2dave

Not correct. Firstly BLEVE stands for "Boiling Liquid Expanding Vapour Explosion"

A BLEVE is caused when a leaky cyl has caught fire. A full bottle on fire is fairly safe as the liquid inside keeps the cyl cool.

However, as the level drops the uncooled steel starts getting hot from the fire and we all know what happens when steel is hot.

Eventually it gets too hot to be able to hold the pressure and it ruptures causing a massive explosion.

Here is a utube of a BLEVE.

https://www.youtube.com/watch?v=UM0jtD_OWLU

I admit, I should have written "VAPOUR".

A BLEVE does not have to involve a flammable or combustible material, nor does it have to involve fire. BLEVE's also occur due to mechanical damage.
A BLEVE occurs when the material of the vessel fails and allows the escape of it's contents, which begin to boil and expand explosively.

I have extensive knowledge of the LPGas industry as a Government Dangerous Goods Inspector, conducting a business involved with the installation & maintenance of LPGas storage & handling facilities as well as tankers. I also managed a major LPGas terminal and was the signatory for the Cylinder Test Station.

I have some knowledge & expertise on the matter.

Irrespective of discussions involving BLEVE's, the law does not permit the carriage of cylinders within a vehicle, except for use in trade when it must be carried secured & upright in an enclosure ventilated to the exterior of the vehicle, OR, carriage between the location at which the cylinder is filled or exchanged to your home.

I used to hold a ticket to transport dangerous goods. This is were I learnt about BLEVE's.

Now my understanding of it is that it is caused by the bottle rupturing due to it being so hot due to the fire. The steel get soft, the container ruptures and then the fire causes the explosion.

If a bottle ruptures with no ignition source there is no BLEVE. And without a fire softening the steel it is highly unlikely for a bottle to rupture in the first place.

How can the liquid boil and expand explosively? When you open the tap and let gas out it is boiling.

Originally Posted by Collins

Irrespective of discussions involving BLEVE's, the law does not permit the carriage of cylinders within a vehicle, except for use in trade when it must be carried secured & upright in an enclosure ventilated to the exterior of the vehicle, OR, carriage between the location at which the cylinder is filled or exchanged to your home.

Do you have a reference for this law?

Kleenheat:
Transporting LPG Cylinders Safely | Kleenheat Gas | Gas Safety

There is no danger with transporting small volume LPG cylinders that are appropriately restrained and correctly filled.
...

No cylinder larger than 9kg (22 litres water capacity) should be carried inside a passenger vehicle.

Origin:
LPG cylinder safety tips - Origin Energy

Safe transportation

Gas cylinders should be secured in an upright position and cylinder valves should be adequately plugged for transportation. In Queensland, cylinders must be fitted with a screwed plastic cylinder plug
Do not carry more than 13.5kg in gas cylinders in a passenger vehicle and only transport cylinders in the boot whenever possible
Transportation of cylinders greater than 250 litres requires cylinder loads to be placarded
Unload cylinders as soon as you reach your destination

NSW Fire dept
LPG Cylinder Safety Check List - Fire and Rescue NSW

Transport:

When transporting cylinders in the car the total capacity must not exceed 9kg. The cylinders should be transported in an upright position, secured, preferably in the boot. Do not leave LPG bottles in a vehicle unnecessarily.
No more than two cylinders should be carried in a car at any one time.