Is it legal to mount a small 5 lb propane tank horizontally on one's roof rack?

WU7X

Snow on the Roof
The title pretty much says it all; is it legal to mount a propane tank horizontally? I'm talking ones normally used in the vertical position with the valve on top of the tank.

I want to mount a small one on the roofrack of my 4Runner. I can't see any dangers doing so as long as one remembers to always close the valve after using.

So, does anyone know what the safety regs say?

Dale
 

WanderingBison

Active member
If by horizontally, you mean on its side, the legality will vary a great deal between “jurisdiction”, which can be at the state or province level in some cases, or county or town level for others. It will be really hard for you to get the legality answer.

The real answer is whether it’s safe or wise to do so - unless a cylinder is designed to be transported horizontally/on its side, when a cylinder is on its side, the liquefied portion of the gas in in contact with the pressure relief device which means that if the cylinder builds up internal pressure above its design pressure, such as when sitting in the sun on a hot day, the cylinder will release liquid propane.

The problem with liquid propane is that it expands over 300 times to one as it changes to gas - so 1 litre of liquid will become 300+ litres once vented and because propane is heavier than air, the gas will sink which makes things worst if the cylinder is on your roof.

Like a lot of safety risks - can you get away with it, of course but should you …

If you can store the cylinder vertically, it’s a much better choice.

Hope this helps!


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Buddha.

Finally in expo white.
As was said above, its not as safe. If it gets hot and over pressurized it’ll vent more dangerous liquid(-44F) instead of less dangerous gas.
 

TwinStick

Explorer
Taking what was said in above posts into consideration, I don't see the reason or the want to lay it on its side vs a vertical mount. I would mount it vertical, as it's a small tank to begin with. Just make sure it is VERY secure. If you're on the highway and have to panic stop from 70-80 mph, you don't want to see your propane tank launch through the back of vehicle in front of you.

When I strap stuff to my roof basket I go on a back road and test it in a panic stop or 2 from 80, just to make sure nothing moves, before I go on my trip.
 

krick3tt

Adventurer
I have two propane tanks, one is a pancake tank that is mounted with the valve on top secured to my roof rack. Never had issues with it except for the occasional branch bouncing off it but I try not to hit things. If my HAM antenna clears then the tank will clear.
The other tank is also 11 pound tank that I mount horizontally with the valve pointed up. I had heard it might be ill advised to mount this tank on its side and that is the reason for getting the pancake tank. I have been carrying the one tank mounted horizontally for years with no problems. It is in the sun (when it is shining) and painted gloss white.
Apparently I may be in the minority on this issue and was not aware of a legal issue and no LEO has ever mentioned it to me.
Interesting question though, I will think on it.

edit: I do not use it in the horizontal position, only for transport to my campsite on the roof rack.
 
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Tedski

New member
I assume you have a height problem and you have the tall 5lb bottels? Why I ask? They make 5lb squat mushroom bottles, I had one. It got out dated and I got rid of it. Couldn't find the short ones so I replaced it with two tall ones and wanted to, like yourself, mount them on the roof. They were just to tall to go up there so I mounted them inside along the wall as low as possible vent out the bottom. I changed the fitting on my stove and tanks to male quick connects and put females on both ends on the hose. I keep both tanks off at the tank and no hose attached (that eventually leak). When i need propane I snap on the hose and turn on the gas. Works great and its very safe. I also added a propane monitor to keep my wife happy! I'd think hard before you put your tank on its side. You could kill somebody, probably yourself!
 

TwinStick

Explorer
Also of note: I was not allowed to cross the Hoover Dam because of my propane tank and extra fuel jugs. So I turned around and took a side road, found a big metal sign, took them off and cable locked them to one of the sign posts. Went back and did the touristy stuff. They were still there when I returned about 2 hrs later.
 

billiebob

Well-known member
In many jurisdictions any and all pressure vessels MUST be secured in a vertical position. Some exceptions exist for things like welder service trucks where the oxygen and acetylene tanks are mounted for use across the chassis, horizontally. But those are specific exemptions.

Your best source for "the correct answer".... your local DOT, MOT guy and your Provincial or State Regulator. Update us with the official reply.

An internet forum is the worst place to ask for transportation of dangerous goods advice. Get the answer from the guys writing the book.
 
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WU7X

Snow on the Roof
Well, it looks like the consensus is to mount it vertically. I was hoping to go horizontally for two reasons; first, ease of access to the valve assembly in camp (I could reach the tank with my 12 foot hose), and second, cut down on potential wind noise. I have a commercially made aluminum mount that will be safely bolted to my existing Camel Back roof rack at the rear driver's side. Will have to make a slight mod to the mount to secure the base better. But big issue from this location is accessing the valve. Something I'll have to resolve.

Thanks for all the input. Exactly the support I've always received from the folks on this site. A couple of pics of the tank in the unmodified mount so you can see what I'm talking about.

Vertical Propane Tank.jpgHorizontal Propane Tank.jpg
 

WU7X

Snow on the Roof
One solution for mounting vertically that I have seen on this site is to use a couple cam-lock straps to hold the tank in place without use of the aluminum mount. Anyone have comments about doing that?

Dale
 

WanderingBison

Active member
In many jurisdictions any and all pressure vessels MUST be secured in a vertical position. Some exceptions exist for things like welder service trucks where the oxygen and acetylene tanks are mounted for use across the chassis, horizontally. But those are specific exemptions.

Your best source for "the correct answer".... your local DOT, MOT guy and your Provincial or State Regulator. Update us with the official reply.

An internet forum is the worst place to ask for transportation of dangerous goods advice. Get the answer from the guys writing the book.

For what it’s worth, I was a Federal Dangerous Goods guy for over a decade and I doubt you will get a solid answer from a Canadian or US DOT guy because in addition to the Federal requirements which may not apply to “us” because we aren’t transporting “for hire”, most of the requirements are from the fuel safety regulations which are mostly provincial in Canada and spread right across the jurisdictions in the US.

Hence, be safe and follow what the manufacturer intended.


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john61ct

Adventurer
Not talking laws just practical safety.

On the side is fine for spares, if filling in relatively cool conditions underfill, like 70% rather than the usual 80%

but never operate that way unless designed specifically for that.

Cover it up.

Ensure rack is VERY strong, enough to keep it from flying in sn accident.
 

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