I’m considering putting in a Generac 20-22kw home generator. If I do I want to run it on propane. I’m not familiar with the underground line sizing. Is there anyone on here that know how the calculation works? I am thinking I would run the propylene line with a tank being approximately 180-220’ away.
The generators full load requirements is 10-12 in water column and uses 3.9 gallons per hour. What would be an adequate run line size?

This is all Greek to me.
I’m thinking it’s 1” line.