propane system configuration

kbrown

Propane question

I have two appliances and each one demands about 200,000 BTU. They are in the second floor of a building so the piping has to be mounted about 15 feet up on the outside wall. Gas man wants to use a dual stage regulator and 1" pipe for the out side of the building but 1" pipe is more expensive and much harder to hang 15 feet in the air. He also suggested this route because he only has one second stage regulator in stock which leads me to what I want to do below.

What I would like to do is run a two stage regulator system so I can use 1/2" piping for the 10 psi run. I would "T" off the 1/2" x10 psi pipe with a second stage regulator and enter the building at the first appliance, hot water heater. (It is about a 35 foot run to the first appliance from the tank) The 1/2" x 10 psi will continue along the outside of the building for another 20 ft. and then terminate into a another second stage regulator that will feed the steam boiler. So I will have a 10 psi trunk line feeding two second stage regulators instead of a dual stage regulator feeding 1" pipe. I know I will be paying for two second stages but the cost savings over the 1" pipe costs and labor to install it will off set that expense. Is it "doable" to use the two second stage regulators off the trunk line to individually feed each appliance provided they are sized correctly?

Kevin

4Johnpipe

I use inches of water column when designing all my gas pipe systems. I would confirm your starting pressure of 10 PSI. 5 PSI is high by me.
At 200K BTU's 1/2" IPS has a .164" pressure drop per foot. 35 feet times .164" = 5.74" WC PD through the section.
10 PSI = 280" of water column. You then take 280" WC subtract the 5.74"WC drop in the section this leaves you 274.26" WC available at the appliance. You would then need to regulate down to the appliance recommended inches of water column. You also need to check for vent limiting the regulator or piping the vent to the exterior.

Tim McElwain

You are dealing with propane so you can run the 10 pound line from the tank first stage regulator outdoors to the second stage regulator. This will give you plenty of pressure from the two points of direction. I would use two second stage regulators coming right out of each one with the normal 10" W.C. pressure for second stage regulators. Then size the piping from the point of delivery (second stage regulator) to the individual appliances and you should be okay. I would try and run as much of the 10 pound line underground if possible. You can use PE pipe for that line. The second stage regulators because they are outdoors do not require a vent, just insure the vent is pointing down so no water will enter.

If you give the two separate loads and the length of run to the appliances I can size your interior piping or tubing depending on what you plan to use.