New Gas Lines Part 2 of 2

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Running new pipe lines allows you to enjoy the practical and cost-savings benefits of natural gas in all areas of your home.


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Do you want to enjoy the efficiency and control of cooking on a gas range, but your kitchen only supports an electric model? Or perhaps you’ve been meaning to move the range to improve the workflow. Would you like to add a supplementary gas water heater closer to your master bath? Are you planning to add a permanent heat source in your garage? Or do you simply want to save money by converting from electricity to gas fuel for a few of your major appliances? Any of these projects is within your grasp as long as your home already has natural gas service. You simply need to install a new branch gas line.
Installing a gas line isn’t difficult, but it is dangerous and in many areas you simply aren’t allowed to do it yourself.
If you choose to proceed with the new line installation, begin by mapping out where the new line will run and calculating what lengths of pipe and which fittings you will need. Begin at the supply pipe you’ll be tying into and work forward. Also check with your local building department to find out which types of pipe are allowed and which types they recommend for your job.
The number of gas appliances a branch line can support is limited by the diameter of the branch and length of runs, so you’ll need to know exactly which other appliances are serviced by the branch you’re tying into and how much fuel they consume (see Gas Consumption of Household Appliances). You will need to obtain a permit and have your work inspected, so it’s good to involve the inspections department up front.
Notes for Installing Gas Lines:

• In most areas, a shut-off valve (usually a ball valve) must be accessible within 3 ft. of the appliance and in the same room.
• If you are relocating a line and cannot remove the existing branch supply line because of limited access, you will need to cap the gas stub-out.
• If you live in an area that allows flexible copper or flexible stainless steel connectors you will have more room for error in your measurements. If you must connect only using rigid black pipe, you may need to have some pipe lengths cut and threaded to fit.
• Most areas allow Type K and Type L copper tubing for installation in an LP gas or natural gas line. But always check with your local building department.
• Never use standard plumbing fittings with gas pipe. Use only gas-rated, cast brass stopcocks for smaller pipe (less than 3" dia.) and use gas-rated globe or gate valves for larger pipe.

Gas Consumption of Household Appliances:
50-gal. water heater (Avg. 50,000 Btu’s per hour and 50 cu. ft. gas consumption per hour*)
Furnace (Avg. 200,000 Btu’s per hour and 200 cu. Ft. gas consumption per hour*)
Clothes dryer (Avg. 35,000 Btu’s per hour and 35 cu. Ft. gas consumption per hour*)
Range/overn (Avg. 65,000 Btu’s per hour and 65 cu. ft. gas consumption per hour*)

*Based on output rate of 1,000 Btu per cubic foot of fuel per hour. Your actual rate will likely differ. Check with your energy company.

Determine the flow rate for a branch line by adding the gas consumption per hour (use above data only if specific information is not printed on your appliance label) of each appliance. Although appliances may not run concurrently, it is advisable to select pipe size based on 100% flow rate. Note that distance traveled also plays an important role in selecting pipe size diameter (1⁄2", 3⁄4", 1", 11⁄4", or 11⁄2").
From: The Complete Guide to Plumbing, 978-1-58923-378-2

What You'll Need


Adjustable Wrench


Adjustable Wrench


Step 1

How to Install a Branch Gas Line

Install a T at the point where the pipe turns up to go through the floor. Connect a short nipple and a cap on the crossbar of the T pointing down. This creates a drip nipple to trap any moisture or impurities in the gas line.

Step 2

How to Install a Branch Gas Line

Push the riser stub‑out pipe up through the hole in the floor. To prevent contamination, cover the end of the riser nipple with tape or plastic.

Step 3

How to Install a Branch Gas Line

Attach an approved 1⁄4"-turn gas valve to the riser stub-out. Apply pipe compound to the male threads. Use an adjustable wrench, not a pipe wrench, to tighten the valve onto the stubout. If desired, slip an escutcheon plate over the riser pipe before you attach the valve (you can also install a split plate later). With the valve off, restore gas to the line at the meter and test all joints with leak detector solution.

Step 4

How to Install a Branch Gas Line

Attach a male-threaded-to-flare adapter to the valve. Use two adjustable wrenches—one holding the valve in place and one tightening the fitting.

Step 5

How to Install a Branch Gas Line

Attach the appliance connector tube to the valve. Make sure to buy a connector with ends that match the valve and the appliance port. In most cases, you may now use flexible stainless steel connectors instead of soft copper tubing that requires flaring. But soft copper is allowed if you have the equipment to make a flare fitting joint and want to save a few dollars.

Step 6

How to Install a Branch Gas Line

Hook up the appliance by attaching the other flare nut to the threaded gas inlet port on the appliance. Plug in the appliance’s power cord. Turn on gas at the main meter and at the stop valve and test the flare fittings for leaks. Once you’re certain all the joints are good, carefully slide the appliance into place.



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