natural gas line sizing

[jmammen]

I need to run a natural gas line from my house to a rental house about 65 yards away. The service line runs in on the other side of the house, so it would make more sense to run from the house, than to run another line, and have to get another meter. There is a 150k btu furnace, and a 38k btu water heater in the rental. The city said that it would be fine for me to run the line myself, and that they would need to hook it up. My question is - does anybody know what size line I would need to use for this? I belive I can use copper tubing or yellow gas line.

Jeremy Mammen
Engineering - Snow Division
Polaris Industries
Roseau, MN

 

[abeltio]

What is the line size of the existing installation?
Use one size smaller (e.g. from 1.00in to 0.75in) but never less than 0.50in (for mechanical integrity). The gas company should have their stds.
Also depending on the size and material of the line you will have to support the line at smaller intervals.
A qualified gas pipe-fitter should be able to give you a good estimate.
Also... make sure you have block valves at each end so in case you have a leak in the system you can isolate the fault.



saludos.
a.

 

[TBP]

The fuel codes I've seen have tables where a minimum specified size of line is identified, based on the BTU/hr load, and the equivalent length of pipe. The code may also lay out minimum depth below grade, and the piping material to be used, approved fittings, etc. You really have to get a copy of the current gas code for your jurisdiction. As a one-shot deal for a small job, I'd hire a properly licenced and insured contractor. Especially when there's very likely a liability issue for a rental property.

 

[davefitz]

The natural gas heater vendor has line sizing recommendations in the installation manual. Also I believe the plumbing code also has sizing recommendations. The total length of supply piping plus factors for elbows are supplied and a table or chart associates the propper pipe size with BTU/hr heat input.

When the 150 MBTU/hr unit first fires, the pressure in the supply line drops , and the pressure change should not be sufficient to trip the ignitor due to lo pressure. This pressure change is related to the sizing of the piping.

If you are running the pipe underground you may need a sleeve or must use sched 40 steel piping. Galvanized is permitted provided the locality never uses synthetic fuel gas . Also, the elect code may require grounding .

Ask the local bld inspector what codes the county subscribes to and check the library.

 

[krb]

TBP is right, use the fuel gas code to size the line. There are tables in the code to tell you the line size based on btuh and length. The local gas company may have a copy, or the local inspector.

 

[jmammen]

Thanks for your help guys. I will cntact the gas company and work from there. I was just hoping to save some cash and do it myself, but that might not be the best route.

-Jeremy