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I want to install a small propane range/stove in my cabin, but don't want the hassle & expense of a giant propane tank in the yard. With the understanding that I use a regulator and the lines have to be sealed and leak-checked, and that the orifices have to be of the proper type, is it safe and proper to run the appliance off of, say, a BBQ cylinder?

In fact what I have is a tall 100lb cylinder that is full which I never use (it has a POL fitting, and I think the newer regulators come with a QCC (correct?) fitting). The other BBQ cylinders have the QCC fitting.

Further ... are the pressures coming off a large, installed commercially-supplied propane tank the same as those from the regulator of a BBQ cylinder? In other words, will my appliance know any difference?

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I want to install a small propane range/stove in my cabin, but don't want the hassle & expense of a giant propane tank in the yard.

Propane appliances are not a problem, but the tanks are. Any propane cylinder or tank should be considered a potential hazard and not stored inside.

People often make exceptions for the small ~14 oz cylinders used for torches and portable stoves. Hardware stores will stock those small cylinders inside the store. However, tanks like the common 20 lb size used with gas BBQs aren't even allowed inside the store.

They're usually kept outside in steel or steel mesh cabinets that act as flame arrestors in addition to protecting the tanks. If you're talking about a 100 lb cylinder, that should definitely stay outside in a protected place away from anything flammable. Check out this advice on storage (tank position is also important).

You can pipe it into the residence, though, just as you would from a buried tank (the requirements are covered by code).

Is it safe and proper to run the appliance off of, say, a BBQ cylinder?...Are the pressures coming off a large, installed commercially-supplied propane tank the same as those from the regulator of a BBQ cylinder? In other words, will my appliance know any difference?

The gas, itself, determines the pressure. When the tank is closed, the pressure will be the same in any size tank. Some of the liquefied gas converts to gaseous form until the pressure is sufficient to keep the rest in liquid form. The size and shape of the tank might affect how quickly the tank can replace the gas being drawn off if you were feeding a monstrous requirement, but for typical residential use, appliances won't care what kind of tank is feeding it. You could use a 14 oz torch cylinder, but you would run out quickly.

I'm not familiar with the tank regulators and fittings that are required by code for different size tanks. Hopefully, someone else can address that aspect.

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  • So what I'm reading here, and from my other research, is that the pressure that the appliance expects is 6oz or 10.5 WC inches. And that is what the BBQ regulators should bring the pressure to. Do I have that right? And yes, I'll look up the code for plumbing the tank in from the outside, which is what I'd planned to do.
    – Kerry Thomas
    Apr 9, 2018 at 4:44
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    I'm afraid my knowledge in that area is that I attach any tank with a matching connector, turn everything on, and it works and I can make burgers, even if I don't know the pressure of the gas coming out of the regulator. :-)
    – fixer1234
    Apr 9, 2018 at 5:13
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Regardless, put the tank outside.

Plumb the house like you would for a huge tank, just bring it to an appropriate enclosure. Put your swappable tank there.

Gas pressure is determined by the temperature of the fuel in the tank, mainly the liquid fuel since it has almost all the mass.

Large or small tank makes no difference.

Piece of bad news though. Ever hear of the latent heat of vaporization? 1 BTU is the energy needed to raise a pound of water 1 degree F. 140 BTU will raise it from 72F to 212F (boiling). But you need to put in about 1000 more BTU to get it to turn into steam at 212F. Only then, additional BTU will increase the steam temp further. Same with propane.

The problem with a propane tank is when you draw off gaseous propane, liquid propane boils to replace the vapor pressure. That boiling propane needs to get its latent heat of vaporization from somewhere. It steals it from the other propane, making it colder. Colder propane has a lower vapor pressure!

Hopefully the tank will absorb enough heat from the environment to keep your propane warm enough to give usable vapor pressure. Otherwise pressure will fade.

Larger tank helps, as it has more surface area.

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    True, and this can be a problem in a frigid climate. As the pressure drops, so does the boiling point. Pressure becomes a problem when the propane temperature approaches -44F, at which point it won't boil. The metal tank conducts external heat well, and the higher that the external temperature is above -44, the faster it replenishes heat. But even in the northern portions of the US, people are able to use propane BBQs in the winter. :-)
    – fixer1234
    Apr 9, 2018 at 3:00
  • Good point re: Temperature ... The cabin is in North Texas, it rarely ever gets to 0. Record low in my area was -11 degrees in January 1989.
    – Kerry Thomas
    Apr 9, 2018 at 4:31
  • That’s why "propane" is actually a mixture of propane and butane that varies seasonally.
    – JDługosz
    Apr 9, 2018 at 5:40
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The pressures are the same but utility supplied tanks often use a 2 stage regulator. At the consumer outlet of the regulator it's NPT (national pipe thread). If your range is a typical household range it will also be NPT. If you use your 100lb cylinder you can get POL regulators and also POL - QCC adaptors. You do however need to get a regulator with NPT at the outlet (sometimes they are press fit with a hose) The system will still have to be leak tight and the orifices still have the be the right size, just the same as a tank. Either way you need to order it propane or convert it from NG to propane.

POL regulator with 3/8 NPT enter image description here

www.amazon.com

POL-QCC adaptor

enter image description here

www.amazon.com

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According to UNI code: Yes you can keep a propane thank inside, but only if room is:

  1. room is neither used to sleep nor is a bathroom
  2. room had a permanent opening next to the floor (6cm^2 per kW with a minimum of 100cm^2), two openings of same size (one next to floor and one next to ceiling) if the appliances is not plumbed to a flue (class A)
  3. storage of any LPG thank is forbidden in rooms smaller than 10m^3, in rooms up to 15m^3 it's allowed to keep maximum ONE up to 15kg cylinder, if between 20m^3 and 50m^3 two cylinders (total up to 20 kg) in bigger rooms up to 30kg in total (no limit on number of cylinders)
  4. storage room should not be lower than ground
  5. tanks must be filled up to 80%
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  • What is UNI code?
    – Mads Skjern
    Dec 29, 2020 at 21:23
  • The UNI is (ente nazionale italiano di unificazione) italian equivalent of the german DIN or the british BS, in simple terms is the group that makes the "regulatory code", in this case, for gas installations.
    – DDS
    Dec 30, 2020 at 10:09
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    If that was a small passive protest against Americans constantly using all sorts of unnecessary and unexplained USA-specific abbreviations, then ... I like it. You gave me a good smile :) Even the fact that it just says UNI without any further explanation, I could hardly have imagined that you were not American :)
    – Mads Skjern
    Dec 31, 2020 at 20:03

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