Anyone real familiar with propane distribution? specifically line sizing?

I don’t run across very many homes that use propane as a fuel source, and most are smaller homes or what I would call standard size. However the home we inspected yesterday is very large, just under 10,000 ft.². and was built just last year. It consists of the main home and then another building that has has a Casita, large garages and also a full court basketball court/rec room. Oh yes and a heated pool.

Propane is used for five furnaces (three at main house and two at the second building). and then also two cool heaters.

At the propane tank there is what appears to be a 1/4 inch copper line from the tank to a regulator and then this splits off to two large lines for distribution to the home and the other(line) to the pool heaters.
M question is how in the heck is this small line supposed to supply all this fuel to the appliances. (but it does as we did run all of these)
Anyone knowledgeable about propane and distribution line size???
( I suppose later on after get this report written I probably have photos to figure the total BTU for all the appliances) But for now, the small line directly off of the tank has me perplexed as to how it can supply enough fuel?? Right now I’m not sure whether just to advise that someone investigate this for sizing or if this is the norm. As you can see in the photo, it looks like a three-quarter inch line could be used but has bushings down to what I believe is a 1/4 inch copper line. Any thoughts?

The tank is under pressure… you can squeeze a lot of volume through short run of 1/4 pipe under pressure. Simple as that :slight_smile: If you’re concerned about sizing, I would be more concerned with the sizing of the regulator(s). Were there other regulators down stream of the red one in the picture?

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Thank you Simon for the input. It is appreciated.

Yes there are other regulators. There is one where the supply line enters the home and also at the appliances. It looks like the home has been set up to use Natural Gas in the future. It is just not available in the area as of yet.

Yeap, the red one is usually first stage, takes you down to 10PSI, the 2nd one (2nd stage) is the appliance, takes you down to about 11" of WC. As an example, 30 feet of 3/4 black pipe will push about 3.8million BTU between first stage and second stage regulator. 3/4 L copper would push 3.4mil. Even with 5 furnaces and 2 heaters should be plenty for 10k sqft house. Say, each one is 200k BTU… which would be crazy oversized :slight_smile: So… as long as everything fired right, that’s about where our SOP ends. If you want to compute the length of the pipe and calculate its capacities… that falls way outside of SOP and can get you in trouble if you screw it up. It will also advertise you doing it… so you will have to do it for each future client (and not forget). It just needs to “look” right, and obviously perform, which you said it did.


Nope I’m not going to calculate anything…As you said SOP found it all working as intended. There were a few leaks discovered at some of the fittings outside that I could “Observe or See”…that is what is going to be reported.
Good information Simon and thank you again, --Larry

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