sizing copper pipe

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

it is also under pressure instead of being basically ductwork.

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.

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.

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.

yes