National Fire Protection Association (NFPA) Regulations
The NFPA requires that every refilled propane cylinder be equipped with an Overfill Prevention Device (OPD). This code went into effect for most states on April 1, 2002. An OPD is a safety device designed to prevent the overfilling of a propane cylinder through a float valve that closes when the propane level reaches 80%. This obstructs undesirable gas venting. Additionally, the OPD stops gas flow when the cylinder is not connected.
Although the OPD is not visible to the naked eye, a simple method of distinguishing whether or not your propane cylinder is outfitted with one is to look at the valve hand wheel that is located on top of the cylinder. This hand wheel should be in a unique triangular shape.
If your cylinder does not have this triangular-shaped hand wheel, then it does not have an OPD. Simply bring your non-OPD cylinder to an AmeriGas Cylinder Exchange Location near you to exchange it with a new AmeriGas Cylinder Exchange cylinder that is OPD equipped and safety compliant.
Click here to find the AmeriGas Cylinder Exchange location near you.