Tuesday, December 5, 2023


Ask Dave: Does my LP tank need to be recertified?

Dear Dave,
Does the permanent propane tank on my rig require recertification after 12 years, as the portable 20-lb. tanks do? —Dennis, 2005 Pleasure-Way Lexor MH 2005

Dear Dennis,
This topic has been a point of discussion back and forth for many years, and you will find a dozen different answers by searching the forums.

First, let’s describe the two different LP or propane “vessels” used in the RV industry.

Types of propane containers

Department of Transportation (DOT) cylinders

Department of Transportation (DOT) cylinders are used in travel trailers and 5th wheel units and can be removed and taken to a filling station. They come in a variety of different sizes such as 20 lb., which is common in the smaller trailers and for grills, and 30- to 40-lb. cylinders used in larger vehicles.

They are also available in 80-lb. models for more extended stay situations.

According to the DOT website, NFPA 58 requires any DOT cylinders 40 lbs. and under manufactured after September 30, 1998, to have an overfilling protection device (OPD) (valve) that limited filling the cylinder to 80%. The OPD valve is identified with a triangle handle. This cylinder has the fill and supply valve in the same location. It also required any cylinder being refilled to have an OPD valve after April 1, 2002.

There is a manufacture date stamped on the handle or colander of the cylinder. These are required to be recertified after 12 years of the manufacture date and every five years after that. The confusion comes from NFPA 58 reclassifying the code in 2017 to change it to 10 years. However, there was much debate and it was reconsidered, and in 2020 it was changed back to 12 years. Even more confusing is because some of the documentation has not been changed yet. This information came directly from the RV Safety & Education Foundation.

American Society Of Mechanical Engineers (ASME) tank

The ASME tank used on motorhomes is a permanently mounted tank that is typically horizontal and in a non-locking compartment. It has a separate fill valve and shut-off valve and has had an OPD valve required since 1983.

According to the Recreational Vehicle Safety & Education Foundation (RVSEF) and Manchester Tank, the manufacturer of most of the ASME tanks used in the RV industry, they do not need to be recertified as they are built stronger, are permanently mounted, and not subjected to as much element deterioration as the DOT cylinder.

Inspection is required on both by a trained refiller

The most critical issue, in my opinion, is a visual inspection by a trained technician when filling. NPFA 58 does have guidelines for inspection such as dents, rust, and broken parts. The challenge is how well-trained are these “refillers,” since there is no real certification process. Since there are so many LP filling stations popping up at fueling stations and hardware stores, the part-time employee is given a quick filling training that is designed for the 20-lb. grill cylinders and not the larger units that require more advanced knowledge of the system.

 You might also enjoy this from Dave 

Wy can’t anyone fill my RV’s LP tank?!

Dear Dave,
We’re having trouble filling our LP tank. We put LP gas into the tank twice. Then four individuals at the local supplier were unable to put LP gas in the tank, so one individual put LP gas in the tank through the exit line. I assumed a new input valve was needed so I had one installed, but it turns out there was nothing wrong with the old valve. I took the RV to a local supplier and another two employees were unable to fill the tank. Then I took the RV to a second supplier and the employee was initially unable to put LP in the tank. He wiggled the hose and was then able to put it in. Why have so many people been unable to put LP in the tank? What is happening? Thanks for your help. —Gordon, 2021 Thor Gemini

Read Dave’s answer

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

Read more from Dave here


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Dave Solberg
Dave Solberghttp://www.rv-seminars.com/
Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. He has been in the RV Industry since 1983 and conducts over 15 seminars at RV shows throughout the country.



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