Scout Olympic Propane CompartmentMost slide-in truck campers are equipped with a propane system. This system, which provides fuel for absorption refrigerators, stoves, water heaters, and furnaces. consists one or two propane cylinders or tanks, a two-stage propane regulator, and a propane low-pressure manifold. The propane cylinders used in today’s truck campers and RVs come in a variety of sizes, the most common of which are rated for 20, 30, and 40 pounds, though some pop-ups and smaller hard-side campers, like the new Scout Olympic, use the smaller 5-pound propane container (shown above).
All propane containers used in today’s RVs must be outfitted with an Overfilling Prevention Device (OPD). This safety device became a requirement in 2002 and prevents propane containers from being overfilled, which for all containers is 80 percent of total capacity (the additional 20 percent allows for expansion during warm weather). OPD valves can quickly be identified by the triangular-shaped knobs with the letters “OPD” stamped on them.
RV Propane Tank Warning
Propane must be used with caution and respect. NEVER ignite an appliance or use an open flame with the smell of propane in the air. Doing so can result is a catastrophic explosion. If you suspect a propane leak anywhere in your RV’s propane system, close the valve to your propane tank, vacate the RV, and have a qualified technician perform a propane leak test. It’s also important to point out that propane explosions in RVs usually involve exploding gas rather than exploding propane tanks.
Did you know that the Department of Transportation (DOT) requires that propane cylinders used in RVs be recertified for use every 12 years? The DOT does, though very few RV owners do it or even know that this requirement exists. What do technicians look for during the recertification process? That the valve guards are in place and in proper working order and that the container hasn’t been subjected to physical damage, such as scraping, denting, and gouging. Dents in containers are allowed, but must be limited in size and must not exceed the sizes specified in the propane recertification charts. The tank’s fittings are also checked to make sure they are in proper working order and do not leak. Failure to recertify can result in a nasty surprise on your next outing as many propane stations will not refill “expired” tanks.
How much does it cost to recertify a 20 pound propane tank? The costs vary but typically you can expect to pay anywhere between $5 and $10.
This 20-pound propane cylinder is due for its 12-year recertification in Nov 2021.After the initial recertification, DOT cylinders must be recertified every five years thereafter. The date of manufacture can usually be found stamped on the outside of the valve guard or found stamped on a metal plate attached to the cylinder. If you regularly swap-out your tanks at gas stations and other propane service centers, your tank is probably okay, though you should check it to make sure it’s still certified and safe to use. Valves and propane fittings do leak and sometimes fail to close even when closed all the way. We had this happen to us in our last camper and encountered another truck camper owner who had this happen to him at the last Truck Camper Adventure rally. This is one reason why we periodically pressure test our camper and check for leaks using a manometer. This is also why we check our camper’s propane leak detector monthly to make sure it’s in proper working order.
Two more things. First, make sure your propane cylinders are properly fastened in your camper’s propane compartment. According to regulation, the propane containers should be mounted in such a way that they will not become dislodged when a load equal to eight times the container’s filled weight is applied to the container’s center of gravity in any direction. Second, when transporting a cylinder to be refilled make sure that the OPD valve is closed, that the plug or dust cap is securely in place over the valve, and that the container is secured during transit to prevent the container from falling or rolling. When transporting, each container should be transported in the same horizontal or vertical position in which they are designed to be used. We like to use a Tanksetter when transporting our single propane cylinder to the local filling station.
Final Thoughts
Have you ever wondered what the 20, 30, and 40 pound cylinder ratings actually mean? It isn’t how much the tank weighs when filled, it’s actually how much propane weight the cylinder will hold when filled. So how much will a 20-pound propane cylinder actually weigh when filled? Easy. Simply add the tare weight (16.6 pounds) of the cylinder to the propane capacity (20 pounds), which for the cylinder pictured above yields a figure of 36.6 pounds. Here’s more. To determine how many gallons this cylinder will hold when filled to 80 percent capacity, simply multiply the water capacity (WC) figure by .10 (47.6 x .10 = 4.8 gallons). To determine how much this propane will weigh in the cylinder simply multiply the WC figure, 47.6 by .42 (20 pounds).
8) There is a lot of fear mongering regarding carbon MONoxide (CO) and is NOT related to carbon DIoxide (CO2). Often the two are conflated. CO2 resipiration is not a health risk in ANY WAY.
When propane is combusted with adequate air (oxygen), the only by-products are CO2 and water (H20). Carbon MONoxide is ONLY abnormally produced by defective equipment. Carbon MONoxide CAN ONLY be produced IF combustion occurs with restricted airflow such as when wasps build a nest in the intake vent of your furnace. Normally, highly restricted airflow will prevent ignition, before a lack of air can cause CO production BUT there is middle ground where it can be produced. EVEN IF CO is produced, a vented appliance such as a furnace, returns combustion air to the outside. ONLY IF the heat exchanger in the furnace is cracked or a window near the furnace exhaust is open, can CO become a human health hazard.
4) As previously stated, propane pressure (in a tank containing liquid and gas) is a function of temperature. You can determine tank pressure (not during use) using a Pressure-Temperature chart (google ‘pressure temperature chart propane’). For instance, at 80F, tank pressure will be 128PSI. The reason this may be important is that the OPD valve on a tank contains a pressure relief device that must be able to release pressure when the tank exceeds 250psi. 250psi is reached at a tank temperature of 129F. While this may seem high and unlikely to be reached, imagine tanks in full summer sun, ‘protected’ by that stylish black plastic (practically unvented) cover (used on some travel trailers). If you occasionally smell propane around the tanks and can’t find it, the pressure relief may be venting slightly due to heat. If you are attempting leak detection at the connection to the valve, don’t ignore leak detecting the BACKSIDE of the valve where the pressure relief is located.
5) Rubber fuel hoses harden over time due to exposure to hydrocarbon fuel. As they harden, they are more susceptible to cracking. Hardening occurs to a greater extent on the inside and is impossible to detect.
6) Propane access doors are legally required to NOT be locked so they can be shut off in an emergency.
7) It is not legal to STORE propane tanks indoors. This is why tank exchanges racks are out front of stores. Many propane servicing centers have expanded on this prohibition by also have signs baring tanks from being brought inside.
Several issues regarding propane
1) There are two ways to recertify a tank. ‘Visual’ is typically done by a trained individual working for a propane supplier. My last one cost $15 for a horizontal 30lb tank ($230 replacement). They apply a label with their inspector code and an inspection date that is good for 5 years. ‘Hydrostatic’ involves removing the valve, pressurizing it with water above its service pressure and measuring the expansion. They re-stamp a test date on the tank and it is good for 10 years. A test will usually take a week, and costs $30+. Until visual inspections were permitted, recertification was typically a death sentence for ‘BBQ tanks’ due to cost. Visual inspections are only available for DOT-regulated propane tanks.
2) A good way to ‘recertify’ is to swap your (20lb) out-of-date tank at your local propane exchange. They don’t object to turning in an expired tank and you can (potentially) get one with lots of years left. This is only useful if you need a 20lb vertical tank. Normally, propane exchange is not economical because you only get 15# of propane in a 20# tank but if a one-time exchange costs you a few bucks, it is a good deal to get a new(er) tank.
3) 1 lb of propane contains 21.6kBTU of energy. If you want to know how long a tank will last, determine the consumption rate of your device and do the math. For instance, a 40kBTU furnace will consume just under, (40kBTU per hour / 21.6kBTU per lb =) 1.85 lb per hour, if it were to run continuously but it doesn’t. Assuming a 30% duty cycle (runs 18 minutes in each hour) then it will consume; 40kBTU per hour / 21.6kBTU per pound x 30% = .55 pounds per hour.
Sometimes you can buy new ones so cheap that it isn’t worth getting a certificate. Besides the valves can start leaking even after certifying and they cost as much as a tank. This is of course for the size that most truck campers use. If I am going out for a long enough stay I make sure I have up to date tanks, at least one. Otherwise I fill at home with my own fill tank. I have forklift, man lift, and horizontal tanks that I fill at home, one tank is a liquid withdraw as well.
We have stopped exchanging cylinders unless out of date or condition is poor. Filling our cylinders, we get closer to 20#, or pay for less if not completely empty. The tank exchange bins (often Blue) in our area only have 15# in them for about the same ~$20.
Might be good to show what the re-certification stamp looks like also.