sizing copper pipe

creger.robert

need to run line from propane tank to barn 160' 300000 btus -this is line from tank to regulator what size line is needed

JUGHNE

Fisher Controls handbook sizing chart has 1/2" OD type L, will carry 400,000 BTUH a distance of 175'.

This is 2 psig pressure drop with 10 psig reg at tank. FWIW

Mad Dog_2

Its amazing how small propane piping can be. Propane packs a high btu punch. Butane is even higher. Mad Dog

mattmia2

Mad Dog_2

Mar 22, 2025

Its amazing how small propane piping can be. Propane packs a high btu punch. Butane is even higher. Mad Dog

it is also under pressure instead of being basically ductwork.

LRCCBJ

Mad Dog_2

Mar 22, 2025

Its amazing how small propane piping can be. Propane packs a high btu punch. Butane is even higher. Mad Dog

If you compare 10 psi for propane to the .5 psi for NG…………….the "amazing" part disappears pretty quick.

The regulator at the house for propane to reduce to .8 psi is the trick.

Propane packs a slightly lower BTU punch as compared to NG.

mattmia2

LRCCBJ

Mar 23, 2025

https://forum.heatinghelp.com/discussion/comment/1849310#Comment_1849310

If you compare 10 psi for propane to the .5 psi for NG…………….the "amazing" part disappears pretty quick.

The regulator at the house for propane to reduce to .8 psi is the trick.

Propane packs a slightly lower BTU punch as compared to NG.

A given volume of propane gas at equal pressures has about 3x the energy content of methane. I don't know why the output ratig of equipment under propane is less than methane but i suspect it burns at a lower temp.

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1849511#Comment_1849511

If you go by my generators engine natural gas provides 10-20% less power than LP.

mattmia2

Here' goes some high school chemistry.

One mole(or more simply the same number of molecules) of any molecule in gas form has the same volume at a given temp and pressure.

Methane is CH4. you burn it and you get 1 carbon dioxide molecule and 2 water molecules.

Propane is C3H8. you burn it and you get 3 carbon dioxide molecules and 4 water molecules.

each of those reactions releases a defined amount of energy so burning a given volume of propane releases almost 3x as much energy.

A piece of equipment running propane vs methane with no modification other than the fuel and air metering has a lower input and lower output burning propane than when it is burning methane. I don't know why this is but I suspect that it is because the propane burns at a lower temp so less work can be done with a given volume and surface area.

LRCCBJ

https://forum.heatinghelp.com/discussion/comment/1849511#Comment_1849511

Here's your exact comparison courtesy of Amerigas:

• 1 cubic foot of propane produces 2516 BTU, and 1 cubic foot of natural gas produces 1030 BTU.
• 1 gallon of propane produces 91,452 BTU, and 1 gallon of natural gas produces 85,098 BTU.

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1849526#Comment_1849526

I don't know about high school chemistry but like I said my generator is rated 10kw on LP and roughly 8kw on natural gas.

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1849530#Comment_1849530

Pardon the possibly stupid question, but how could two different units of volume (cu ft vs gallon) have different ratios of energy like that?

2516 to 1030 = 2.44
91,452 to 85,098 = 1.07

Are the gallon units in liquid vs the cu ft units being gas?

mattmia2

https://forum.heatinghelp.com/discussion/comment/1849661#Comment_1849661

yes

mattmia2

Did we lose the op completely? I think the why does the same equipment fired with propane have a lower capacity than when fired with methane is a @Tim McElwain level question because it isn't the energy content of the gas, at least not directly.