The propane attendant readied to sling our seven-gallon cylinder in the back of the car. “Would you mind setting it upright, please?” we asked. He shrugged his shoulders, and said, “You know, it really doesn’t matter. It’s safe whether it’s standing up or lying down.” But he put it upright, as we asked. It begs the question: Is it safe to carry LP cylinders lying down? For that matter, is it legal?
The “why” behind the admonishment
Most have heard that LP cylinders should be transported upright. Rarely do we get the “why” behind the admonishment. There’s a good reason though, as we learn from Magnus Olsson, a safety engineer with Linde, an international firm that deals in pressurized gases. Olson says it comes down to a safety valve, built into the propane cylinder’s shut-off valve. The safety valve has a pretty limited act in the “LP stage play.” If pressure in the cylinder builds up too high, endangering the integrity of the vessel, the safety valve opens, releasing the pressure.
What happens if the LP cylinder is lying down? The safety valve is no longer at the “top” of the configuration. When the valve is at the top, should it open, it will vent LP vapor. But if the cylinder is lying down, one or two different things could happen—both of them bad. One possibility is the safety valve could clog—failing to release the excess pressure. The other, the safety valve will work as designed, but instead of LP vapor, liquid propane can come out of the valve.
Here’s the problem: While LP vapor is flammable enough, a small amount is less likely to get you in trouble. But if liquid comes out of your cylinder—liquid petroleum—it will expand. Exponentially. Read it this way. If, say, a liter of liquid petroleum hits the atmosphere outside of the cylinder, you’ll quickly end up with 250 liters of flammable vapor. No, it’s a stretch to say your 5-gallon cylinder would vent a whole liter of liquid petroleum, but you get the picture. If that vapor finds a source of ignition inside your rig, then hope your life insurance is paid up.
What could “trip” a safety valve?
Still, what’s the likelihood of your LP cylinder safety ever tripping? Again, it would take high pressure in the cylinder to set off a safety valve. What could cause that? Propane gas supplier Levco says, “Temperatures would need to reach higher than 120 degrees Fahrenheit or 40 degrees Celsius to cause a rupture,” or a safety valve release. Most of us don’t need to worry about hitting those kinds of temperatures, right? What if your LP cylinder is lying down in the back of your SUV on a hot sunny day? A study conducted in Arizona showed that a car parked in the sun for just an hour on a 100-degree day can shoot the cabin temperature up to 116 degrees. Park a little longer, and you could easily test your LP cylinder safety valve effectiveness.
This is another reason to think about what color you might repaint your LP cylinders. Off the shelf, most are brilliant white, or at least a good “highly reflective” color. Folks tricking out an older RV might be tempted to give everything a nifty matching paint job. Fine, paint the siding on your Shasta chocolate brown if you must. Just leave the LP cylinders bright. The darker the color, the less the heat reflectivity, and the greater the likelihood of overheating the contents of the cylinder.
And that legal stuff
Safety aside, there are legal considerations about transporting LP cylinders. The federal regulations that apply come from the Department of Transportation. Here’s a note about how much propane you can legally carry in your rig from lpgasmagazine.com. “A person must carry no more than four propane cylinders in a sedan or SUV at one time. No single cylinder should contain a propane capacity of more than 45 pounds, and the total combined weight of all the cylinders in an enclosed vehicle should not exceed 90 pounds.” With propane scaling in at approximately 4.2 pounds per gallon, the upper limit is about 21 gallons. Three 7-gallon cylinders is the maximum for inside a vehicle.
But suppose you get elected to haul all the empties from the big campout you and your buddies put on? If you haul those cylinders outside—in an open truck bed or on a trailer, the rules change. Lpgasmagazine.com comments on this: “Customers may transport up to 1,000 pounds of propane in the back of an open pickup truck or trailer. However, the propane cylinders must still be transported in the vertical and upright position.” We’ll use 5-gallon cylinders here—the math’s easier. You can move 200 of them at a time.
Keeping them upright
Keeping LP cylinders upright and secure can be a bit of a trick. One of the patriarchs in our family would have described the design of these gas containers as “tippy-arsed.” And indeed, left on their own, the slightest rocking motion will dump your typical cylinder over. Several outfits make plastic bases that LP cylinders can be set into for transport. Here’s one from Flame King, sold on Amazon.com. For less than $12 a pop, these might be the answer.
Many RVers use milk crates to keep their cylinders upright. But unless you’ve got a friend in the milk distribution business, we found milk crates on Amazon cost more than these plastic rings made for the job. We don’t encourage sneaking around behind grocery stores to “pick up” a crate or two. Spending a few bucks on a “real” stabilizer is probably easier than time in the hoosegow for a “free” milk crate.
Of course, if you transport LP in the back of your pickup, you might try a method that one of our readers has done. He’s designed an extremely sturdy and efficient “tie down” system. Check out our story, Safely carry LP cylinders in your pickup with this clever mod.
In any event, don’t transport your LP cylinders lying down. You could be asking for a personal disaster that’s easily avoided.
Well explained. Thanks!
Remember that Bottles of compressed gas are not unlike a toy balloon when you release it after blowing it up. The main difference is it can be like a Rocket engine and can be propelled like a rocket. Whenever you see a welders truck, the gas bottles are either being secured in the upright position or with the valve end facing the rear of the truck. If the valve is damaged the bottle would be forced to the bead or the cab of the truck. Otherwise, it could be propelled off the trick to oncoming traffic.
I have found that using a Plastic Milk Crate, the bottle stays in the upright position and can be made more secure while traveling and less likely to tip over and damage the valve.
Wow! Never knew about this! Thank you for the explanation and the great information.
I have some heavy plastic crates that work, a squatty tank fits. If there is too much room in the crate, I can place something in one end of the crate so it won’t tip.
One solution is to strap all the tanks together in a geometric pattern(Square, rectangle,etc.). This becomes highly stable laterally. Then secure the “Package” to the vehicle.
I believe your math regarding propane in the back of the pickup is incorrect. 1000 lbs of propane at 4.2 lbs per gallon is 238 gallons, which would be 47 5-gallon tanks, not 200. Still, it’s doubtful anyone would want to fit that many into the back of a pickup.
Makes sense. What about the black plastic covers many manufacturers are using for propane setups? Seems to not be a great idea for heat dispersion.
If you have to use a car/SUV to transport a cylinder, a seat/shoulder belt works pretty great to keep it upright ,and will not let it fly around in a sudden stop. Do keep windows open; just in case gas should leak. In some states, it may still be illegal to transport in a car or truck cab.
Maybe they should make the valve so the tank can be carried horizontal or vertical. This way you could transport the 30 or 40 lb cylinders under cover out of view in your pickup bed. While they do make small horizontal cylinders, they are expensive.
That might be a bit of a trick. The valve vent cannot be in the liquid portion of the contents. I can’t imagine a design for a fixed valve that could achieve that.
It is the law to carry acetylene and oxygen bottles in the upright position with safety caps installed and a way to secure those cylinders from falling. I always treated the propane tanks the same way! Propane can kill you! Enough said!
My supplier of acetylene oxygen and argon insists they put them in my bed of truck. Always lay down. They even strap them down
If we are to transport propane cylinders upright, why are they mounted on their sides on fork lifts????
Forklift cylinders are designed to vent vapor vertically and in a specific horizontal rotation.
different type of cylinder. Even some RV propane cylinders are designed to be horizontal but it is a different cylinder and not interchangeable with a vertical cylinder.
Propane fuel tanks for forklifts are designed differently and the safety pressure release is specifically designed for a horizontal tank. BTW, if you really need a 20# propane tank that travels horizontally they do make them. I have two. They are not cheap!
That is scary to know the guy filling the tank wasn’t taught on basic safety in handling the LP tanks!
Milk crates are a much easier way to carry and transport LP cylinders. The holder you show is fine but the crates are much more stable and have handles to carry or secure them in transport. They are available at various stores for about $8-10 each. Tractor Supply and Target are 2 places I’ve found the same type and brand crate.
The guy filling the tank was taught how to fill the tank, not how to safely handle the tank after filling it. My experience with the young people today is the employer is lucky to get them to come to work each day. Asking them to learn more is really taxing their brain. Besides their job description is to fill the tank, your job is to know how YOU need to transport it.
The holder shown is the same as what is used on the tongue of a travel trailer. There is a bottom metal pan with a center threaded rod, a notched cross bar, and a big wing nut to lock the tanks in place.
I have 2 of the rings, similar the ones depicted in the photo in the article. They are excellent and at a great price point. In the cooler months, I carry 2 x 20lb cylinders in the basement of our class A using these and highly recommend this style. Though they are tremendously stable and simple in design, I still use a light strap to secure the tanks in place preventing them from sliding in the event of sudden stops and travel with zero fear of them tipping. More functional than the stolen milk crates I used for 20 plus years.
Contrary to some opinions I’ve heard, it is not illegal to use milk crates for propane tanks; it is just illegal to steal them. You can purchase milk crates (or shall we say, plastic webbed crates identical in dimensions to the plastic crates used in the dairy industry) from at least some of the big box hardware stores. I prefer them over actual propane stabilizers as I can also use them to transport other items at the camp site when not in use for propane tanks.
Thanks for the informative article! And as a side note, I just LOVE the word “hoosegow.”
From dictionary.com “In Spanish, juzgado means “panel of judges, courtroom.” The word is based on the Spanish past participle of juzgar, meaning “to judge,” which itself was influenced by Latin judicare—a combination of jus, “right, law,” and dicere,”to decide, say.” When English speakers of the American West borrowed juzgado, they recorded it the way they heard it: hoosegow. They also associated the word specifically with the jail that was usually in the same building as a courthouse. Today, hoosegow has become slang for any place of confinement for lawbreakers.”
What brought on the Spanish language lesson?
Russ used the term hoosegow in his article to indicate where you might end up if you steal a milk crate.
is somebody upset?
Frequently. Just sayin’. Have a great day, Chris. 😀 –Diane at RVtravel.com
I scroll right past anything with his name. Too negative!
Hi, Mary Beth. You’re not the only one who has made that observation (there have been several, actually). For someone who claims to be so happy, he certainly comes across very negatively frequently, especially by putting other people down. So something in this scenario “does not compute,” at least for me. Have a great day! 😀 –Diane at RVtravel.com