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LP-Gas Systems on Campers and Recreational Vehicles

Safety Tips

Because of its portability, liquified petroleium gas (LP-Gas) provides you with modern conveniences no matter where you travel. Stored as a liquid and used as a gas, it will cook your meals, heat your vehicle, keep you supplied with hot water, and even refrigerate your food. LP-gas -- whether it's propane, butane, or a mixture of the two -- is non-toxic, safe and economical.

Like any fuel, however, LP-gas is combustible. This page contains some important points for safe storage, handling and use of LP-gas containers, systems and appliances. If others traveling are unfamiliar with LP-gas, or if you lend your vehicle to someone -- be sure to acquaint them with these safety tips as well.


When produced, LP-gas is both colorless and odorless. For safety reasons, a chemical odorant is added so that, in the event of a leak, you can detect the escaping gas by its strong, distinct smell. Ask your LP-gas supplier to familiarize you and your family with this smell.

Under certain circumstances, propane gas may lose the distinctive odor that was added. This is sometimes called "odor fade", and it can occur both in new steel containers when first placed into service and in used steel containers left open to the atmosphere for a long time. In addition, under certain circumstances not everyone can smell the odorant in propane. Physical conditions such as competing odors, common colds and allergies, smoking, etc. may lessen a person's ability to smell.

If you think the odor of your propane gas is weak, or if your sense of smell is impaired, call your propane supplier. A service technician can verify the odor of the propane gas in your tank. And if your sense of smell is impaired, consider installing an electronic gas detector in your RV.


If you suspect a leak, follow these steps:

  1. All occupants should leave the vehicle immediately.
  2. Do not operate electrical switches or light a match.
  3. Turn of all gas appliances.

  4. Close all cylinder or tank supply valves immediately.
  5. Open all doors and windows and let fresh air blow away the escaped gas.
  6. Call a trained gas service person and do not turn the gas on again until the leak has been found and corrected.


LP-gas, usually propane, is sold and stored in containers that, when properly filled, contain about 80% liquid. The remaining 20% of space above the liquid contains propane vapor. It is the vapor that burns in your appliance when mixed with air. The vapor space in the propane cylinder also provides room for the liquid propane to expand if the cylinder is exposed to warmer temperatures.


If a cylinder is overfilled (that is, beyond 80 percent capacity), there won't be enough vapor space to accommodate the expanding liquid if the cylinder is exposed to warmer temperatures. Any of the following potentially hazardous conditions could occur:

  1. The pressure relief valve may open, discharging propane to relieve the pressure.
  2. Propane liquid could enter the piping system, resulting in higher than normal pressures to the appliances.
  3. If the cylinder becomes liquid full and the pressure relief valve fails to open, the container could rupture, resulting in serious injury or property damage


New cylinders or used cylinders that have been exposed to the atmosphere must be purged of air before being filled.


There are two basic types of portable propane cylinders we'll talk about -- the vertical (upright) standard cylinder and the horizontal cylinder that comes with a special mounting bracket and which can be installed either vertically or horizontally. Both cylinders are manufactured in accordance with U.S. Department of Transportation (DOT) specifications.

When you purchase a new cylinder, be sure it fits the bracket you have. Vertical cylinders can only be used standing upright, whereas horizontal cylinders are designed for service while lying on their sides. If they are interchanged, propane liquid rather than vapor could enter the piping system. This might cause excessive pressure and, possibly, a fire or explosion.

Finally, when you install your new or refilled cylinder, remember that, to a single cylinder system, all appliance valves must be turned off before you open the container service valve.


It is important for you to be familiar with the type of cylinder(s)you own. Installing the incorrect cylinder could allow propane liquid to enter the piping system, causing your appliances to malfunction and creating a fire and explosion hazard.

Cylinder Markings

Cylinders approved for use with LP-gas (both propane and butane) will have one of the following specification numbers following the DOT or ICC stamping: 4B-240, 4BA-240, 4B-300, 4BW-240, 4E-240 and 26-300. The "240" in the DOT 4B-240 designates the service working pressure of the cylinder. Only cylinders with one of these markings may be used for LP-gas.

Cylinder Requalification

Department of Transportation regulations require that all DOT or ICC cylinders be inspected and requalified within 12 years of the date of manufacture and on a regular basis thereafter -- every 5 years if it's inspected visually, for example. This inspection is typically done by a qualified technician when your cylinder is refilled. For information about cylinder inspection and requalification, consult your Propane Gas Dealer.

Your cylinder should also bear a decal which identifies the contents as a flammable gas by name and international I.D. number (UN 1075). Other cylinder warning labels available from your propane gas dealer are useful for future reference. Ask to have them applied the next time you take your cylinder in for refilling.


Filling a DOT propane gas cylinder that has not been properly inspected and qualified violates federal law.


Whether you're transporting your propane gas cylinder or storing ot for future use, you need to handle it carefully. Here are some safety tips you should follow:

  • Propane gas cylinders must be transported so the relief valve communicates with the vapor space at all times. For that reason, you should never transport a cylinder lying on its side unless it's a cylinder designed for horizontal use.

  • When transporting disconnected cylinders, the container outlets must be plugged or capped. This will keep gas from escaping and prevent foreign material from entering the cylinder should the valve be opened accidentally. (The threaded safety plug has left-hand threads, so you'll have to turn it counter-clockwise to tighten it.)

  • Never use, store, or transport full cylinders or empty ones in the passenger space or living area of your RV or camper.

  • Any cylinder that is damaged, shows signs of corrosion, has been exposed to fire, or appears to be leaking gas should be removed from service immediately. Store defective cylinders in a safe, outdoor location. Then as soon as possible, have them repaired or disposed of by a qualified service technician.

Refueling Portable Cylinders

New cylinders must be properly purged of air by a qualified person prior to filling for the first time. This is because air left in a cylinder will affect how your appliance works. The presence of air can also diminish the odorant level in the container and cause excessive pressures. Once a cylinder has been properly purged of air, keep the cylinder valve closed, except when connected for use.

DOT cylinders are filled by weight or fixed liquid level gauge to insure against overfilling. Be sure to have your cylinder filled by a qualified individual, and if filled by fixed liquid level gauge, have the weight of the cylinder checked occcasionally to assure that the tube in the fixed gauge is properly located and giving an accurate measurement.


Only personnel trained in the proper filling procedures of DOT cylinders should engage in this activity.

Refueling Permanently Mounted Containers

Before entering the refueling area, turn off all pilot lights, appliances, and automatic ignition devices. Before permanently mounted propane containesr are refueled, all passengers should also leave the vehicle after the engine is turned off.

The fill operation should be stopped as soon as the fixed liquid level gauge indicates that the maximum safe fill level has been reached.

NOTE. Some of these filler devices are equipped with an automatic stop-fill capability. The appliances can then be put back into operation after the vehicle has left the fill area.

  1. Make sure all appliance valves are shut off.
  2. Shut off the manual shut-off valve on the cylinder(s) supplying propane to the system.
  3. Disconnect the cylinder (left hand thread) and remove for refilling. Install a protective plug in valve outlet if transporting.
  4. Prior to reconnecting the cylinder to the service line, secure cylinder in a cabinet or bracket and remove the protective plug.
  5. Reconnect the cylinder.
  6. Check your appliances to be sure that appliance gas valve are still turned off inside the vehicle.
  7. Turn on the manual service valve on your cylinder and check for leaks with an approved leak detector solution. Be sure to check that control equipment is operational and not stuck in the "open" position. Do not use a match or an open blame to check for leaks.
  8. After you are sure the system is leak-free and the controls are operating properly, relight all pilots, following the manufacturer's instructions.

Securing Containers

Make sure your propane gas containers and regulators are installed and properly secured in or on your vehicle so as to minimize damage in the event of a collision or accident. Depending on the type of vehicle, cylinders and regulating equipment can be located as follows:

  1. Travel Trailers and Tent Trailers: On the A frame as close to the front of the trailer body as possible.
  2. Motor Homes, Vans, Fifth Wheel Trailers for Slide-in Chassis-mounted Units: In a recessed compartment, accessible only from and ventilated ot the outdoors and gas tight to the interior of the vehicle. Pressure relief valves must be pointed away from the vehicle or toward the container compartment opening.

Because propane vapors are heavier than air, the compartments for all propane containers aboard your vehicle must be ventilated, both at the top and bottom, and completely sealed from the interior of your vehicle.

Containers located on the rear of a vehicle must be securely fastened and protected by substantial bumpers. The vehicle's minimum normal road clearance under maximum load conditions must never be compromised by the location of a propane container.


Propane gas containers should not be mounted on the roof or in front of a vehicle.

Container Maintenance

Protect the outside of your container with light-colored, heat reflective paint (such as white). This will help reduce the increased pressure as temperatures rise, and protect against rust and corrosion. Aluminum cylinders do not require painting.

NOTE: If your vehicle is involved in a collision or other accident, shut the gas supply off at the container and have the system checked by a qualified propane gas service person. Again, never use an open flame to check for leaks.


Propane gas reacts to temperature changes. When the temperature drops, the pressure in the container drops. When the temperature increases, the pressure increases. A regulator assembly must be provided to maintain a constant delivery pressure to your appliances at all times. Two-stage pressure regulation must be used on all RV's.

Attach the regulator assembly directly to the container valve or on the bracket with a flexible high pressure connector between the cylinder valve and the regulator. Remember the pressure between the container and the regulator assembly is tank pressure, and this is the reason for requiring a high pressure connector.

NOTE: Do not attempt to repair a regulator -- call your propane gas dealer if service is required.

When tightening a POL fitting into the service outlet valve (left-hand thread) of the cylinder, use a smooth jawed wrench (such as a crescent wrench). Do not over-tighten. This brass fitting is designed to be leak-tight without the use of pipe compound. Finally, be careful not to scratch or damage the round nose of a POL seat.

Protecting Your Regulator

Propane regulators must be protected and installed to prevent the vent's clogging due to rain, snow, sleet, ice, condensation or road spray. To prevent the regulator from being exposed to these conditions, special shielding protection must be provided.


A blocked regulator vent could result in excessive gas pressure to appliances, or regulator failure, which could result in injury or property damage.

Preventing Regulator Freeze-Ups

The presence of moisture in the fuel may cause the regulator to freeze up. The following suggestions may help you prevent regulator freeze-ups and allow moisture to pass harmlessly through the regulator.

  1. Always keep the cylinder (or container) valve closed and POL plug in place when not in use to prevent moisture from collectcing inside the container.

  2. If you suspect the presence of moisture, your propane dealer can inject methyl alcohol into your cylinder (or container) before filling.


Approved and properly adjusted appliances are very important. Improper flame adjustment (which you can detect by a yellow flame at the burner tip) is dangerous. With adequate ventilation, an operating burner gives off harmless products such as carbon dioxide and water vapor. However, a propane appliance starved of oxygen can quickly produce dangerous amounts of carbon monoxide and may result in asphyxiation. When operating your oven and/or range, open a vent and window to insure an adequate supply of air for safe operation. Never use the oven for heating the recreational vehicle.

Carbon Monoxide

Carbon monoxide is a colorless and odorless gas, and can't be detected through your sense of smell. If you are exposed to carbon monoxide you may experience any or all of these symptoms:

  • Headaches, tightness across the forehead and temples

  • Weariness, weakness, dizziness and vomiting
  • Loss of muscular control
  • Watering and smarting of the eyes
  • NOTE: If any of these symptoms should develop, get into the fresh air immediately, and have your propane system checked and repaired as needed.


    1. Never use the oven or stove top burner to heat your vehicle.
    2. Never use any camping or other portable heater that is not designed and approved for your vehicle or is not approved for use with propane gas.
    3. Never take a barbeque grill (propane or charcoal) inside your vehicle to cook or heat with.
    4. Have all appliances, including venting and burner system, tested for proper operation by a qualified propane gas service person.
    5. Always be sure your vehicle is properly ventilated.
    6. There are commercial detectors available that can be easily installed inside a camper to warn of the presence of carbon monoxide.
    7. Heaters used in RVs must be approved for RV use and be of a sealed combustible type or heave other special vent systems.

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    The information provided above by National Propane Gas Association, 1600 Eisenhower Lane, Suite 100, Lisle, IL 60532