Propane Gas Tanks and Grills

Most consumer propane tanks are the 20 lb variety that can be refilled or exchanged and are used most commonly in outdoor grills for open flame cooking.  Many retailers, hardware stores and convenience stores will have tanks to refill or exchange.  They are commonly visible in cages outside the front of these stores. For obvious safety reasons they are stored outside of the structure.  

Re-fillers are required to be licensed and have strict inspection requirements. The 20 pound propane tank has had a few changes over the years to improve safety: Tanks must be hydro-statically pressure tested after a certain number of years.

An Overfill Prevention Device (OPD) is required to prevent filling a propane tank beyond 80% capacity, this is done to ensure that tank does not become liquid full and expel propane out of the relief valve.  The triangular valve design is an external indication that an OPD has been installed.

Effective April 1, 2002 All 4# to 40 # propane cylinders must be equipped with an OPD. If the cylinder is not equipped with an OPD, the cylinder cannot be filled with propane.

Grills have made a few changes over the years to improve their safety, also: The design must be such that multiple tanks cannot be stored inside the grill cabinet. This is to prevent the spare unused tanks from becoming overheated. Overheating can result in over pressurization and expel propane out of the relief valve. The cabinet design can have a barrier or other obstruction, or exclude multiple tanks by volume.

I recently investigated a case where there was no OPD installed, the re-filler overfilled the tank and a spare tank was placed inside the cabinet of a non-compliant grill. The result was an incident where a consumer received severe burns while cooking when the spare tank expelled propane that was then ignited.

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If you are looking for more information, contact or email Gary L. Jackson, P.E., CSP, CFEI, at 800-624-0905.