Propane Locker Code Basics for Van and RV Safety

Why propane lockers exist and what the codes are after

Propane is an efficient onboard fuel, but it is heavier than air. If it escapes, it sinks and collects low, which is why code language revolves around sealed storage and gravity friendly venting. A locker is a dedicated compartment for cylinders that is gas tight to the interior and vented to the exterior at its lowest point. The goal is simple: if a leak occurs, vapors fall through a direct vent to the outside instead of pooling inside the cabin.

Most guidelines you will encounter echo similar principles found in respected standards for mobile applications. They converge on a few themes: isolate the fuel, provide a path for heavier than air gas to exit, eliminate ignition sources in the compartment, and make shutoffs accessible. Treat the locker as a miniature mechanical room, not a storage cubby.

Core propane locker code basics you should know

• Sealed from the living space: The locker must be fully sealed on all sides against the interior. Use continuous gaskets, sealed seams, and a closing lid or door with a compressive seal. No penetrations are allowed without gas tight bulkhead fittings.

• Low vent to the outside: A drop vent at the lowest point allows heavier than air propane to exit by gravity. This vent should go directly to the exterior and remain unobstructed. Screens should be corrosion resistant and sized to maintain open area.

• No ignition sources inside: Do not place switches, relays, outlets, or lighting inside the compartment. Regulators and pressure relief vents must discharge safely to the outside, not into the living space.

• Materials and corrosion control: Lockers should use durable, non sparking construction with rust resistant hardware. If wood is used, encapsulate it and protect penetrations so the seal remains gas tight for the long term.

• Cylinder orientation: Portable DOT cylinders must stand upright so pressure relief devices point upward. ASME tanks are fixed mount and external; if you are storing removable cylinders, ensure the locker supports upright restraint only.

• Access and serviceability: The manual cylinder valve must be reachable without removing the cylinder from the locker. The door or lid should open fully for removal and inspection, and latches should hold fast during travel.

Venting and drain details

Think of the vent like a floor drain for vapor. Place it at the very bottom of the locker and route it straight down or out with a continuous fall. Avoid long horizontal runs. Do not combine the vent with any other system or locate it where road spray can blow back into the compartment. Many builders add a second high vent only for air makeup when opening the door, but the critical requirement is the low vent to atmosphere.

Penetrations and fittings

Every line that passes through a locker wall should use a bulkhead fitting designed for gas service. Avoid simply running hose through a hole, even with grommets. Sealant alone is not a substitute for a mechanical gas tight interface. Protect copper or stainless hard lines from chafe and maintain gentle bends to prevent stress.

Regulators, pigtails, and overpressure protection

Two stage regulators provide stable appliance pressure. Mount the regulator where it can vent to the outside and remain accessible for replacement. Use listed pigtails with excess flow protection and ensure adequate clearance around the cylinder valve so the handwheel and OPD features function as intended.

Securing cylinders and preparing for the road

• Restraint system: Cylinders must be secured so they cannot move under braking or cornering. Use rigid brackets or metal straps anchored to the locker structure, not just to trim panels.

• Crash considerations: Avoid mounting the locker where a minor rear impact could compromise the compartment. Reinforce attachment points and distribute loads across the van body or internal frame.

• Temperature and ventilation: Keep the locker out of engine bay heat and away from exhaust. External airflow at the vent helps disperse any escaped gas faster.

Testing and inspection

Before opening any cylinder valve, perform a pressure decay test on the downstream system using a manometer. After pressurizing, isolate the system and watch for loss over a defined interval. Then apply an approved leak detection solution to every joint, including bulkhead fittings and appliance connections. Document test results and recheck after the first few shakedown drives.

Frequent mistakes to avoid

• Vents that rise before exiting, which trap vapor
• Shared compartments with batteries or electrical gear
• Hinged doors without continuous gaskets
• Running flexible hose through walls without bulkhead fittings
• Stowing tools or gear inside the locker that can damage valves

Bringing code principles into a real build

The safest approach is to design the locker first, then route lines and place appliances. Start with cylinder size, clearance, and service access. Position the low vent where it exits cleanly, away from dust or spray. Choose a regulator location with a straight shot to the pigtail and a protected path for the outlet line. Keep appliances as close to the cylinder as your layout allows to minimize fittings. Finally, plan inspection points with removable panels, so periodic leak checks are easy and you will actually do them.

Professional van builds that meet propane locker code

If you want the benefits of onboard propane without compromise, professional layout and fabrication matter. OZK Customs designs and builds sealed compartments, gravity vents, and secured mounts that pass inspection and stand up to real travel. Explore our Recreational vans to see how we integrate safe fuel systems into functional interiors, then choose the path that fits your journey with our Custom van builds or ready to finance Mainstream vans.

We listen first, then engineer a propane system around your cooking, heating, and hot water needs. From sealed lockers and bulkhead fittings to pressure testing and documentation, our team delivers a complete, compliant install.

Ready to build it right

A well designed propane locker is like a safety valve for your entire interior. When it is sealed, vented, and serviceable, you cook with confidence and sleep easy.

Contact OZK Customs to discuss your travel style and system goals. We will tailor a fuel plan inside a purpose built adventure rig that balances safety, function, and long term service.

Strong finish begins with smart planning. Share your vision and we will pen the blueprint.

Ready for a propane system that passes inspection and performs on the road? Tell us how you travel, and OZK Customs will design a compliant, serviceable fuel layout inside a purpose built adventure van. Fill out the form and let’s build it right the first time.

• Learn more: Recreational vans
• Start here: Custom van builds
• Browse options: Mainstream vans