PROPANE NEWS

On April 1, 2002, 4 to 40 pound vertical non-stationary Department of Transportation (DOT) propane cylinders must be updated by law. It will be illegal to refill most portable cylinders not equipped with the new style OPD-fitted valves. The previously ubiquitous POL (bullet nose, left-hand thread) valve has been replaced by a new valve fitted with an overfill prevention device (OPD) and a Type 1 fitting for connecting pigtails.

The 1998 Liquefied Petroleum Gas Code section of National Fire Protection Association (NFPA) Standard 58 called for the installation of OPDs on all 4 to 40 pound vertical DOT cylinders manufactured after September 1, 1998. The 2001 version of the same code states that horizontal cylinders are exempt from an overfill protection device (OPD) retrofit as long as the cylinder was manufactured prior to Oct. 1, 1998. That means that these cylinders can be legally recertified after 12 years without making modifications. The tanks mounted to motorhomes (designated as ASME tanks) are not subject to this regulation.

There are limits on how much propane can be put into a cylinder. Because propane expands as it gets warmer, it is important not to exceed a cylinder's proper filling limit. A properly filled cylinder will have a vapor space left in the top of the cylinder to allow room for expansion of the liquid with a change in atmospheric temperature. Proper refilling is dependent on the operator, it is possible to overfill the cylinder by inaccurate weighing, ignoring the presence of liquid propane at the fixed-level gauge, or relying on a float-type dial gauge. The OPD helps prevent potentially hazardous conditions caused by cylinders that may have been overfilled.

OPDs are intended to reduce the danger associated with these kinds of possible errors, by automatically stopping the refilling process without the operator's intervention. The new OPD valves prevent overfilling of gas cylinders, making filling and using gas cylinders safer than ever before. The OPD consists of a float mechanism attached to the cylinder's refilling valve that cuts off the flow of propane as soon as the propane level reaches the container's rated 80 percent liquid capacity. The presence of an OPD does not relieve the operator from the duty of determining the proper fill level by one of the other standard methods.

OPD-equipped cylinders have a special triangular hand wheel, which cannot be removed, and are marked with the letters "OPD" on the valve body. They are equipped with Type 1 fittings, also called Quick Connection Coupling (QCC) fittings, that allow connections of the pigtails without the use of tools. This coupling is designed so that no propane flows unless the mating connector is fully inserted. These cylinders use the plastic hand nut that fits over the 1 5/16 inch outside right hand Acme threads for the new-style hose fittings. QCC-equipped valves also have inside left-hand threads that will accommodate the old POL fittings.

Installing OPDs on older POL-equipped cylinders is in most cases feasible, however, the expense involved will probably have many people buying new cylinders instead. Check with you local propane dealer to have the proper valve installed in your cylinder. There are some cylinders for which an OPD replacement valve does not exist.

For 20 pound cylinders, one upgrade strategy would be to exchange your old POL cylinders for new OPD tanks at a propane exchange depot. Make sure you get the right valve if the cylinder is for RV use.

Properly dispose of any old propane cylinders. Check with your local LP-gas company. Many companies that sell new cylinders will accept your old ones for disposal. Do not throw them in the garbage as they are considered hazardous material.