Safe Propane Installations
By Tom Burden, Last updated 2/04/2019
Once you experience the ease of cooking on a propane stove, you’ll never go back to kerosene or alcohol. Propane stoves light instantly and are as easy to use as a home gas range. The flame burns clean without the odor that comes with kerosene and is much hotter than alcohol.
The Potential Problem with Propane
Propane gas is heavier than air and will collect in bilge areas if a leak exists, resulting in a possibly explosive situation. However, with proper installation, basic safety precautions and common sense, the possibility of an explosion can be eliminated.
Regulators & Pressure Gauges
A pressure gauge, whether a separate unit or built into the regulator, must be installed immediately after the main tank valve and is used to detect leaks in the propane system, not as a fuel gauge. It cannot give you a precise measurement of the remaining fuel because the pressure remains relatively constant in a propane system until the fuel runs out. You have to weigh the tank to get an accurate measurement of remaining fuel.
Regulators reduce the propane’s pressure from approximately 150 psi to 0.5 psi, the pressure appliances are designed to use. There are two methods of connecting a regulator to the tank. The Single Stage Regulator with Gauge screws directly onto the tank at the POL fitting. To mount the regulator remotely from the tank, use a Single Stage or Two Stage Wall Mount Regulator. Remote regulators have 1/4" inlets to accept a pigtail with a 1/4" male flare on one end and a POL fitting on the other.
All connections between the propane tank, regulator, and solenoid valve need to be made in a vapor-tight compartment separated from the interior of the boat, or outside of the boat in a location where leaking gas will not drain to the interior of the boat. If your boat does not have a built-in propane locker that vents directly overboard, we offer ready-made propane lockers. A vent line, as shown in the diagrams from the lowest point of the locker, must drain overboard above the waterline. The tanks must be well secured so that they cannot tip over and leak or become damaged.
Solenoid Control Valves
A solenoid is an electrically-controlled valve that allows you to shut off the gas supply from a remote location. The switch is commonly located on a small panel in the galley area, and has a red light to indicate when the propane solenoid is open. Flip the switch off and the valve closes to shut off the gas. For safety, solenoids close in the event of a power failure. We offer solenoid valves with either 1/4" or 3/8" NPT ports. For multiple appliances, the extra flow of gas allowed by the Full Flow 3/8" Solenoid Valve helps prevent “gas starvation” downstream. To connect it directly to the regulator, use a 3/8" brass pipe nipple. All pipe thread connections must be sealed with a proper thread sealing compound or Teflon tape.
To carry the gas from the regulator to the stove or heater, use LPG supply hose of the correct length. Note that while these hoses are only carrying 0.5 psi, they have a 350 psi working pressure rating, so they are dramatically stronger than they have to be. Each supply hose should run continuously from inside the propane tank enclosure to the appliance: this is not a case where you can chain a bunch of fittings together because you ended up a little short on hose. Use a Vapor-Tight Straight-Thru fitting where the hose exits your propane locker. Supply hoses connect to the propane appliance using a 3/8" female flare swivel and connect to the solenoid with a 3/8" male NPT adapter.
Common Propane Installation Mistakes
Boat U.S. provides the following info from marine surveyors about the problems they most often see in the field. Check your boat for these unsafe situations:
Plugged vent in propane locker: Without a way for leaking gas to escape, propane can accumulate to dangerous concentrations in the locker. Periodically remove the tank, pour water in the locker and verify that it drains directly downward, with no low pockets to collect water. Check lid gaskets for proper fit and sealing.
Wiring attached to gas line: Having an electrical wire tied to a propane line is a bad idea. If there is a short, the wire can become hot enough to melt through the hose.
Storing junk in propane lockers: The propane tank is the only thing that should be in the propane locker. One surveyor noted an anchor in the locker that had scratched the paint off the tank and caused it to rust. Heavy objects can damage the regulator or gauge during a rough outing, and sharp objects can cut the hose. Make sure that the propane tank is properly secured in the locker so it cannot rattle around.
One gas line supplying multiple appliances: Gas lines for each appliance should originate at the tank, preventing a junction inside the boat. No junctions mean fewer opportunities for leaks.
No working propane detector: While not required by ABYC specs, these inexpensive, easy-to-install detectors can save your life. If you have a detector, check the date of manufacture. They typically have a reliable lifespan of five years. Don’t forget to test the detector periodically. A little fuel released from a butane lighter can be used to check the sensor.
Lack of chafe protection on gas lines: Whenever hoses pass through bulkheads they need chafe protection. Constant movement and vibration on a boat can cause hoses to wear against a hard surface and leak. Hoses must be well supported with non-chafe fittings.
Rusted tanks, regulators and solenoids: Replace rusted components right away. Even if the date stamped is still valid, a rusted tank could fail at any time.
No operating instructions posted: Someone unfamiliar with the boat might not know to turn off the system after use, or know proper lighting instructions.
Manual shutoff valve behind stove: Reaching over a hot fire to shut off the valve is a bad idea, especially if there’s a leak at the stove. Much better is a remote electric solenoid shutoff mounted on the tank.
Missing or inoperable pressure gauge: Without a reliable gauge, there is no way to test the system for leaks, which should happen regularly, especially after repairs, a severe grounding or collision.
Weathered, cracked or improper fuel hoses: Hoses won’t last forever, especially if exposed to sunlight or heat. Manufacturers typically rate hose life at 10-20 years. Surveyors have reported seeing gasoline and air hoses used in place of proper UL-Listed propane hose.
Spare gas cylinders (large or small) stored inside the boat: Spare propane tanks must be stored the same way primary ones are—never down below. Even small cylinders for portable appliances must be stored in a vented locker or on deck.
In the words of one experienced surveyor, “It is well worth an extraordinary inspection effort when you have a propane system.”