Propane bottle safety cap?

[InterBlog]

Airstream Interstate van owner here, with very little experience when it comes to portable propane BBQ-style bottles. Please forgive me if I have missed a previous thread on this topic.

Am I losing my mind, or does the type of propane safety cap or plug I am searching for basically not exist...?! Or it exists only as a very expensive item, or DIY-cobbled-together item?



I'm talking about a bottle valve device that would prevent the discharge of propane in the event that something accidentally hit the valve handle, jarring it out of the closed position and allowing propane to escape uncontrolled. I've seen videos of exactly that type of accident happening. BBQ cylinder tumbles over in the bed of a truck, handle gets bumped, propane starts spewing. I don't know why these things would not come with safety caps to start with.

I'm talking about a leak-proof cap, not a dirt cap.

Here are the two options I've found thus far, and my question posed in picture form:

[waninae39]

Get a cheap plastic one from any place that fills the tank

No cost

[wachuko]

Originally Posted by waninae39

Get a cheap plastic one from any place that fills the tank

No cost

Those are not safety caps... She is looking for one that, even if the valve is open, propane would not leak...

I have only come across the first one...



US$30.00 for peace of mind does not seem like much... imho of course...

https://www.amazon.com/Leak-Free-Bra...2288829&sr=8-4

[GetawA-S]

Those tanks are designed to only discharge when a tight fitting hose is attached. If a tank spews propane when the valve is bumped, it is defective and should be replaced.
...unless I am missing something here.

[rmkrum]

Newer OPD tanks (the ones with external threads) have valves that are designed to prevent “spewing propane”. It’s also good sense, and in some places a requirement to properly secure tanks in a vehicle to prevent them from falling over or bumping valves. A properly tightened valve is unlikely to bump open.

Plastic plugs, as noted, will keep small leaks from going too far as well.

Tie the tanks down, transport safely.

[InterBlog]

Originally Posted by rmkrum

Newer OPD tanks (the ones with external threads) have valves that are designed to prevent “spewing propane”. It’s also good sense, and in some places a requirement to properly secure tanks in a vehicle to prevent them from falling over or bumping valves. A properly tightened valve is unlikely to bump open.

Plastic plugs, as noted, will keep small leaks from going too far as well.

Tie the tanks down, transport safely.

This is an interesting point - I will test a valve in a safe manner. Maybe even video it.

Properly secure, sure. But those who rely on single-option safety measures often answer to Mr. Murphy, the guy who wrote the famous law. If proper stowage was all that is ever needed, we wouldn't have safety dispensers on gasoline cans either.

[InterBlog]

Originally Posted by wachuko

.....

US$30.00 for peace of mind does not seem like much... imho of course...
....

I may end up going for it, but it is worth asking first. It just didn't make sense to me that a $30 cap would be the only true option produced for a $35 tank. In the Interstate context, I have 2 new tanks I would like to fit with this backup measure. And 2 more at my stick-and-brick. So it starts to add up.

[wachuko]

Originally Posted by InterBlog

I may end up going for it, but it is worth asking first. It just didn't make sense to me that a $30 cap would be the only true option produced for a $35 tank. In the Interstate context, I have 2 new tanks I would like to fit with this backup measure. And 2 more at my stick-and-brick. So it starts to add up.

I looked at these when working on the setup for my truck... for whenever I get out to camp in remote places with it (some day...). I wanted everything disconnected and plugged for safety when driving over rough terrain.

At the time, that was the only option that I could find and I saved it in the Amazon wishlist...

Even if my tank will be secured to the the camping kitchen box I made (which in turn is secured to the truck bed), I wanted to take no chances. In my case it was just one 20lbs tank, so only one cap. But yeah, add the sliders, the wood, the stove, water tank, etc. It just keeps adding up...

[JCWDCW]

Originally Posted by GetawA-S

Those tanks are designed to only discharge when a tight fitting hose is attached. If a tank spews propane when the valve is bumped, it is defective and should be replaced.
...unless I am missing something here.

Yes you are right
The propane valve will not discharge if there is no hose attached This is a DOT requirement in the design
JCW

[Wazbro]

What about a plastic one that screws in.
https://smile.amazon.com/Manchester-...2383262&sr=8-5
The new valves still have internal threads.

[InterBlog]

Research limitation - these stories are generally published without follow-up that explains exactly what happened, where the failure was. The dramatic scenes are newsworthy. The technical details, not so much.

Here's an example of a tank that started spewing propane in the bed of a pickup truck. You can see the white vapor condensation seconds before it ignited in an explosion.

Then around the 1 minute mark, you can see the tank's emergency mechanism kicks in as it vents pressure.

But what happened to cause the release from the tank in the first place? Did the tank tumble over and bump the handle? Was it a product defect? Improperly plumbed tank? No idea. I looked at the corresponding news media reports, but other than blaming the tank (duh, obviously), I could not find any details.

1.5-minute video.

https://www.youtube.com/watch?v=p7RNYw11XHM

[davidz71]

Tank was probably not secured and when the vehicle stopped the tank fell over. The valve probably hit something that was in the bed knocking it off the tank which allowed a rapid release of propane. Hard to say what ignited it but if the valve was hit by a piece of steel then there is the spark that ignited it.

[InterBlog]

Wwwwell, the purpose of hatching a thread is to learn new stuff, and that is certainly happening here.

I just procured two new small tanks for future travel (hence my interest in safety caps) and it's also time for me to re-fill the 20-lb tank that I keep at home for our BBQ. When I took the tanks to my local U-Haul yesterday, the staff refused to fill them. Said I had to take them to a "real" propane servicer to get them purged first.

It says on the label that the tank should be "purged of trapped air" but it does not say that it needs to be "flushed five times" which is what U-Haul told me. I had assumed that the liquid propane flowing in would displace the air, effectively purging it, and that would do the job. Nope.

I looked it up on the internet, and sure enough, a similar claim is made. So I will be taking the tanks to a full-service propane facility hopefully today. I will ask them about the valve function, and whether some sort of safety cap is advisable.

I wonder what people do who keep larger portable tanks at their properties? Eventually my husband and I will get either one or two 100-pound Manchester tank for our camp shack. We can get them purged prior to transportation but we certainly won't be able to purge and fill prior to transportation. I'll ask that, too.

[GetawA-S]

Be advised that there are limits to the amount of propane you can transport inside a passenger vehicle. I believe there are also limits to how much can be transported in a pickup truck bed.

[GetawA-S]

DW has had her coffee, so I had time to look this up:
Inside a vehicle, no more than four cylinders, none larger than 45 pounds, total max 90 pounds.
In the bed, max 5 cylinders, max 1000 pounds, must be transported upright. (Rack and chain, in my experience)
Keep in mind that a filled 100 pound tank will weigh almost 200 pounds. (Tare weight is stamped on the collar)
Have you considered a rental tank, if available? These typically allow for on-site refills, and if it gets stolen, you might not be out for the cost.

[InterBlog]

Mystery solved. The reason why I kept seeing "spewable" portable tanks still in service is, well, because they are still in service for a variety of reasons, some legit, and some not. For instance, if people need to transfer propane from one tank to another, they are sometimes used for that. For normal consumer use, all of the older valves should have been replaced by now with the one-way valves mandated after 1998. But not all of them have been. Some people did not bother, and some less-scrupulous servicers will continue filling the old-style tanks.

TL;DR image summarizing the difference:



True enough, those triangular newer handles will not release propane if turned when nothing is connected to the tank. They do not require a separate safety cap.

Also during this excursion, I discovered that there is a better "baby tank" design than the one I found on the internet. Because I was searching for 5 pound options, this 4.5 pound version did not appear. I should have checked with our local brick-and-mortar before making a decision. A lot of these tiny tanks are sold to boaters who wish to BBQ on board (the propane facility owner initially assumed that I was a boater, too).



On the issue of new tank purging, the proprietor muttered something about how these things are shipped pre-purged and shouldn't need it, but he did it anyway. He added a partial fill of propane to each, when he then vented the works before doing the final liquid fill.

[Wazbro]

Originally Posted by InterBlog

Mystery solved. The reason why I kept seeing "spewable" portable tanks still in service is, well, because they are still in service for a variety of reasons, some legit, and some not. For instance, if people need to transfer propane from one tank to another, they are sometimes used for that. For normal consumer use, all of the older valves should have been replaced by now with the one-way valves mandated after 1998. But not all of them have been. Some people did not bother, and some less-scrupulous servicers will continue filling the old-style tanks.

Not quite all normal consumer use tanks need the valves replaced. At least when I checked 3 years ago the horizontal tanks (used on some Airstreams trailers) did not need the new valves.

[DAllerton]

The newer bottles with the triangular handle (QCC1) will not allow Propane to escape without something being attached to the valve itself. In fact, if you were to hook it up to your grill and open the valve with your burners already on you will find that it doesn’t work either. It has an excess flow device installed in the valve to prevent this. You can turn the handle open (counter clockwise) and no Propane will come out if it’s not connected to anything. By installing something onto the threaded connection you are actuating the valve and overriding the safety mechanism, thus allowing Propane to escape if the handle were to be opened. For safety, your efforts would be better spent in securing the tank and making sure that it does not tip over and rather remains upright at all times. It has a relief valve on it which relieves pressure should it become too great such as if your tank were to be overfilled and then warmed by the sun or kept in the hot trunk of a car. If the tank is upright it will vent vapor but if it’s laying on its side it will vent liquid propane instead which expands 270 times and volume as it turns to a gas and immediately create an extremely dangerous situation. I wouldn’t worry about the valve so much as just simply securing the tank itself.

[mythbuster88]

For stability while in the bed of our truck our spare propane tank sits in a square plastic milk crate type box. The box is secured so it can't fall over.

The stuff is dangerous but not as bad as gasoline!

[InterBlog]

On the issue of stability, that little tank I showed in the image above that I wished I had bought?

I caved, and I bought it. It's just SO NICE to have a tiny propane tank that will sit on the floor of my vehicle and not roll around.

My next task is to devise a secure way of storing it on the roof of our Airstream Interstate van. It's out of the way of potential impacts (such as rear-end crashes) if I put it up there.

Magma grill (disassembles and packs down small) with Ukrainian cast iron skillet which has a removable handle that allows the lid to close all the way. Bacon!!