Propane Tank Vacuum Purge

[1L243]

I purchased new 30# tanks for my RV. They came shipped to the house with a sticker that says they have to be vacuum purged. This does not sound like something the local propane filler can do? Is it necessary and if it is what's the procedure?

[mobeewan]

Proper procedure for purging a propane tank with propane vapor (propane gas) and why.

propane cylinder purging

I believe you only have to do use propane vapor (propane gas) 3 times on the smaller DOT cylinders of 100 lbs and less, but I can't find the link.

Looks like I might be wrong. Everything I can find says 5 times. Including regulations from the Utah State Fire Marshall.

Yes boys and girls. Some state regulations require cylinders shipped with air to be purged with propane vapor (propane gas) for the reasons stated in the link above.

I can't make a shortcut to the Utah link, but if you copy paste what I put below into your browser it will pop up in the search. Other state propane regulations may also show up. So regardless of what the maysayers state about being unnecessary state regulations may require purging.

Utah LP-Gas-Basic-Filling-Procedures-Gen-Info-1

[Old-Biscuit]

New propane cylinders are shipped either with 100# Air pressure OR under a vacuum

Air Pressure........Cylinders need to be 'Vapor Purged' 4 times to remove all air

Vacuum......propane vendor just fills them. NO Purging necessary


Check that 'sticker' again.

[SDcampowneroper]

Its a gimmick. Fuel to air ratios fall between the too rich and too lean for combustion, even then there has to be an ignition source in that critical % state in side the container.

It has never happened. Purging is just a gimmick used by suppliers to charge you for something you do not need. Big tanks like 500 gallon tanks are shipped and filled with air at atmospheric pressure. They are not vacummed or purged. The negligable air and oxygen becomes too rich of a mixture to burn,

Propane 101
Ask your local firefighter.


The potential water vapor could be a concern IF filled on 100% humidity day, IF used on much a colder day in which the tank empties to allow the water to boil. Otherwise, water will become and remain liquid until the pressure drops so low as to cause it to boil off or to freeze dry. That would be far below the boiling point of propane at -44.3 f Niether is ever likely or documented. It just cant happen

Talk to your local firefighter. not your propane supplier Its akin to asking to a used car salesman vs a scientist One will tell you its safe , the other truth. both will tell you its safe
Talk to your local fireman!

[mobeewan]

Sandia Man wrote:
Never had issue with new tanks that had this sticker on them, last set I took over to ACE hardware to have them filled.

I have. I bought 2 30 propane cylinders that were not purged that I had nothing but trouble with them. My furnace would backfire and shut down requiring me to have to turn the furnace off and back on to reset it. Luckily for each cylinder bought at different times I had refilled the original cylinders. Once I switched to them the furnace ran flawlessly.

A propane supplier burned off the propane in the cylinders with a rig he had. Then he removed the valves and rinsed the inside with an alcohol product to bind any moisture inside the cylinders to it. He then reinstalled the valves, purged the cylinders and refilled them. Both worked perfectly after that.

[Nv_Guy]

If liquid propane is put in the tank without first purging the tank, the concern is that the moisture in the air will instantly freeze to the sides of the tank & you really don't want moisture in the tank.
You want to get all of the moisture laden air out of the tank.
This can be done either with vacuum or several rounds of vapor & vent. I don't know why the tank mfg. said to use vacuum purge. Is it possible that the sticker said the tank had been vacuum purged?

[rhagfo]

Just means that the propane dealer doesn’t need to use propane to purge the air from the tanks. Otherwise they need to put a small amount of propane in the tank then release it to flush any air out of the tank.

[time2roll]

If they use the vent when filling does the air not come out? Worst case the lighter than propane air should come right out the top when first used.

[Sandia_Man]

Never had issue with new tanks that had this sticker on them, last set I took over to ACE hardware to have them filled.

[Sjm9911]

Yup they can do it.

[enblethen]

Take them to your local Suburban or Ameri-gas facility. They should do it for free with filling the tanks.

[azdryheat]

Take it to an actual propane store.