North Carolina issues stop-sale order for propane cylinder refilling device

In North Carolina, a stop-sale order was issued for a cylinder refilling device. While this stop-sale order only applies in North Carolina, other states may want to heed the safety warning and not allow the device to be filled.

We received notice from an industry expert on problems with filling cylinders with a certain refilling device and conducted similar tests. We verified the expert’s concerns and identified additional safety concerns.

The device features a frame, four 1-pound refillable, proprietary propane cylinders and a single fill valve for filling all attached cylinders simultaneously. The company makes many claims about the convenience and safety of filling the cylinders with this device.

The only places we found for buying the device are online at various outdoor activity sites and a major online retailer.

The claim we found to be untrue and the most dangerous was that using the device for filling the attached cylinders would fill them to equal and safe levels. Our testing showed that cylinders would get filled liquid full, close to liquid full, and underfilled, all in one filling operation. The statement that the fill levels of connected containers would equalize over a short period of time was found to be false. The instructions they provided were contradictory and inconsistent with LP-Gas Code requirements and basic logic for anyone familiar with filling containers.

Most 1-pound cylinders are non-refillable. The U.S. Department of Transportation bans any of these non-refillable cylinders from being filled and then transported to a different site. Some of the filling methods described in manufacturers’ instructions and on YouTube will not cause the cylinders to be overfilled, but a few of them would allow cylinders to be overfilled to the point of liquid full. The best advice is not to fill them.

The basic idea for most refillable cylinders is that liquid is transferred from another container, usually from a grill cylinder, using only propane pressure and gravity for the transfer. No pump is involved. Since propane will not flow when container pressures are equal and no pressure exceeds the equilibrium temperature/pressure when no pump is used, overfilling is unlikely when container-to-container transfer methods are used. And there’s no flow unless a bleeder valve is opened.

Properly designed refillable cylinders are a realistic option. We found that some cylinders are not properly designed. Other cylinders are fine.

The device of concern is designed to be filled using a pump at a typical dispenser.

There are no safeguards from overfilling if the cylinder bleed valve or valves are not used or are ignored.

There is no safe automatic shutoff available. Using a pump means propane is pushed at a pressure higher than tank pressure.

Any delay in closing the hose-end fill valve once the bleeder valve indicates full can easily result in an overfill because of the small volume. If the operator thinks there is an automatic shutoff, the likely result is as many as four overfilled bottles ready to pop off or explode.

Other device deficiencies include:

⦁ Tare weight markings are insufficient, and they lack precision.

⦁ Water capacity markings are inconsistent with net weight declarations on the label.

⦁ It’s easy, and likely, to fill the cylinders to more than 85 percent.

⦁ O-ring retainer sleeves in the cylinder openings are prone to not staying in place, which would lead to leaks during filling if they’re not present.

⦁ The design of the fill valve indicates it’s an OPD valve, but no stop-fill device is present.

⦁ The fill valve indicates it has a bleed valve. There is no bleed valve that is part of the fill valve.

⦁ The instructions provided are vague and contradictory.

⦁ The distributor stated on its website that the device is UL listed. The documentation it provided was not for this device. UL says that it does not list the device.

The stop-sale order will require manufacturers and distributors to remove this product from retail locations in North Carolina within six months. Online sales shall include a note that this product is not legal in the state of North Carolina.

Richard Fredenburg is an LP gas engineer at the North Carolina Department of Agriculture and Consumer Services, Standards Division. He is also a member of NFPA’s Technical Committee on LP Gases. Contact him at richard.fredenburg@ncagr.gov or 984-236-4752.

NOTE: The opinions and viewpoints expressed herein are solely the author’s and should in no way be interpreted as those of LP Gas magazine or any of its staff members.

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