Propane is one of the safest and easiest fuels to store but it is a combustible fuel and needs to be given due respect.  Disregarding proper safety in handling, transporting and storing propane can have devastating consequences.  A small green 16 oz canister of propane has the same explosive power as a stick of dynamite.  A 20 lb cylinder used for your BBQ grill can level a 3-story house.

Improper handling, transporting or storage of propane can have disastrous results including explosions that can cause property destruction, personal injury and even death.  Read and obey all manufacturer instructions.  Follow all safety rules.


What is Propane

Propane is a by-product of natural gas processing and petroleum refining.  Propane was first identified in 1910.  The US produces 90% of the propane used in the US with most of the remaining 10% coming from Canada.  After its production, North American propane is stored in huge salt caverns in Mont Belvieu, Texas, Conway, Kansas and other locations.

Propane is a gas but under pressure becomes liquefied.  Propane is sometimes called LP Gas, which actually stands for Liquefied Petroleum Gas.  Propane is the most popular LP Gas but Butane, Propylene, Butylene, and several other gas are also LP Gases.

Propane is 1.5 times heavier than air.  Unlike natural gas that is lighter than air and will rise and dissipate when released, propane will sink and pool at the lowest level available when released.  This trait creates some storage concerns which will be addressed later.

Propane’s octane level is less than gasoline’s but greater than natural gas’.  In a tri-fuel generator, you would need a richer fuel setting for propane than for gasoline and a leaner fuel mix than for natural gas.

Propane is naturally odorless, so an odorant, usually ethanethiol, is added so people can easily smell the gas in case of a leak.


Bulk Propane Cylinders


Transportable consumer propane storage cylinders range from small green 16.4 oz single use cylinders to bulk refillable 20 gallon/100 pound cylinders.  The most popular size is the 5 gallon/20 pound cylinders used for BBQ grills.  Here is a chart for bulk refillable consumer propane storage cylinders.





Capacity (gallons)
Weight (empty)
Weight (full)
Overall Height
BTU Capacity

4.7 gal
18 lbs
38 lbs
18 inches
12.5 inches

7.1 gal
24 lbs
54 lbs
24 inches
12.5 inches

9.4 gal
29 lbs
70 lbs
29 inches
12.5 inches

23.6 gal
68 lbs
170 lbs
48 inches
14.5 inches


Storage cylinder care is important.  The cylinders are made of metal with a paint coating to prevent rust.  If the cylinders are bumped or hit the paint can be scraped off and rusting can occur.  If left unattended, the rust can ruin the cylinder.  I suggest keeping a can of white rust resistant spray paint around to quickly take care of any scrapes or dings that may occur on your long-term storage cylinders.

Cylinders must be certified to be refilled.  A cylinder is considered certified for 12 years from the manufacture date and then must be recertified every 5 years after that.  I usually have my tanks refilled at a bulk refiller (someone who has a big bulk storage tank and charges you by the gallon to refill your cylinder) sometimes they check the date and sometimes not.  By law they are not suppose to refill out of date cylinders.

Several years ago, cylinder valves were upgraded to OPD (Overfill Protection Device) valves.  The new type valve prevents overfilling and prevents leaks from the valve.  If you have an old style valve on your cylinder, bulk refillers will not refill it.

If you have out-of-date cylinders or cylinders with old style valves, don’t get rid of them.  I’ll tell you how to trade them in for newer ones later.


Where to Get Cylinders

The first question is do you want new or used cylinders.  If you plan to keep your cylinders in storage and use a bulk refiller for the occasional refill, then I’d buy new cylinders.  5 gallon/20 pound cylinders at Costco or Sam’s Club sell for around $30.  Costco occasionally has 20 gallon/100 pound cylinders for around $90.

Once you get your 5 gallon cylinder you’ll need to fill it and at $2.50 per gallon, it will cost an additional $12 or so, for a total of $42 for a new filled 5 gallon cylinder.

New cylinders are pressurized with air for transport.  The first time you fill your cylinder with propane, the air needs to be blead-out.  Most bulk refillers know how to do this but just make sure you let them know if it is the first time a cylinder is being used so they can bleed-out the air.

A second option is to go to your neighborhood gas station, convenience store, home improvement center, or Wal-Mart and buy a full used 5 gallon cylinder for about $50 depending where you live and the store you buy it from.

The downside to buying pre-filled propane exchange cylinders is that it is industry practice to down-fill the tanks 10% – 20%.  In other words, don’t expect 5 gallons of propane in your cylinder.  You will get more like 4 to 4.5 gallons of propane in the exchange tank.


Updating and Recertifying Old Cylinders

There are a lot of out-of-date cylinders and cylinders with old valves out in the world.  Many people with old RVs, trailers, and run-down BBQ grills have old cylinders that can’t be refilled and they don’t know what to do with them.

This presents an opportunity for people in the “know”.    There is an upside to using a propane exchange if you have an old cylinder.  Most propane exchange places just want a somewhat decent looking cylinder from you when you exchange it for a filled cylinder.  Some exchange places require cylinders with updated valves, but many are not picky about the cylinder you bring in to exchange.

The Home Depot by my house has an automatic exchange kiosk.  You swipe your credit card for either purchase or exchange, a cage door to a single tank is unlocked automatically, you take the full tank and place your old tank back in the cage if you are exchanging, all without ever seeing or dealing with a real person.

I exchange my old cylinders at a gas station by my house that lets me pick which tank I want to take and has never turned down an old cylinder for exchange.  Many people have similar success at Wal-Mart.

Pick up old cylinders at garage sales or any other place that you can find them, then exchange them for full, refillable cylinders for the exchange price of $20 or less.



Propane cylinders should be transported in the upright position.  Propane exists as both liquid and gas in a cylinder.  The liquid is at the bottom and the gas is at the top of an upright cylinder.  The cylinder valve has a pressure release feature that only works if it is upright so the gas part of the propane is at the top.  If the cylinder is on its side and the valve is rotated to the bottom of the tank where the liquid propane would be, the pressure relief feature cannot work if it is needed.

You should also try to keep the cylinders from clanging and banging into each other or anything else during transport.  Being banged around can scratch the cylinder finish which can lead to rust.  It can also potentially cause damage to the cylinder valve.


Propane Storage

Propane cylinders should be stored in the upright position so that the gas portion of the propane in the cylinder is at the top of the cylinder by the pressure relief valve.

Cylinders should be stored in a well ventilated area away from any ignition source. Propane should not be stored indoors.  Propane should never be stored in a basement and should never be stored in a garage attached to a house.

Remember, propane is heavier than air and will pool to the lowest level possible.  If you store propane in a basement and have a leaky cylinder, the leaked propane will pool on the basement floor.  Most houses have furnaces and water heaters in the basement.  Pooled propane and an ignition source is a disaster.

Some houses have furnaces and water heaters in the garage.  Same disaster scenario as above if you store propane in the garage.

Cylinders should be stored in an outside shed or storage area on a flat dry surface.  Don’t store cylinders where they can be bumped and banged or on damp surfaces such as grass or mud.  This risks exposing the cylinders to conditions that may cause rust.


Propane Usage


Propane is stored under pressure.  Bulk propane cylinders (5 to 20 gallon) need a Low Pressure Regulator to reduce the pressure from the tank to the appliance you are running.  Many appliances like BBQ grills come complete with a regulator.  I keep an extra low-pressure regulator with a 5 foot hose in storage just in case.



Other appliances like a propane heater or camp stove that are made to run on 16.4 oz cylinders need an Adapter Hose to run off of a bulk propane cylinder.  Mr. Heater makes a 12′ Adapter Hose.

Read all the instructions for the appliance you plan to run on propane and make sure you have the appropriate regulators, adapters, and hoses.

Most propane appliances are for outside use only.  There are some ventless heaters that are considered indoor safe (as a safety precaution, I never run these heaters while I sleep).

The same cautions about storing propane also apply to  using propane.  Bringing a bulk tank into a house to run an appliance can be a disaster if you have a propane leak.  Keep all bulk tanks outside.


A Propane Extension Hose is available to run from an outside tank to an indoor appliance.  If you combine an 8′ or 12′ Extension Hose with a 12′ Adapter Hose, this would give you a 20′ to 24′ hose which should be plenty long to run from an outdoor tank to an indoor appliance.


How Much Propane Can I Store?

How much propane you can store depends on the ordinances of the city or town you live in.  In general, non-transportable tanks over 20 gallons/100 pounds require a permit to be install on your property.  In the jurisdiction I live, there are no ordinances specifically about storage of propane in transportable cylinders.

Read and follow the ordinances for your area.


Ed Rogers
Copyright “Keep It Simple” 2013. All Rights Reserved.

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