Plumbing and running natural gas & propane gas lines
Comments script being abused, so reworking it...
|How to run natural gas or propane gas lines in your
house without blowing anything up
|We have all been taught that running a gas line is so dangerous, you should
just not bother. Just pay the professionals. This sort of teaching breeds
ignorance and in a time of crisis when there's no plumber around, you might
One thing that I like to remind people is that most people with a normal
sense of smell will be able to smell a gas leak way way way before it is
going to do any harm (assuming the gas is collecting in a relatively enclosed area). Let me give you an example. When we moved into our
house, all of the pilot lights on our old stove had burned out (there are
3 pilot lights). The house had been vacant for a month and there was a distinct
smell of gas in the house. Natural gas sort of smells like sulfur or a rotten
egg. Keep this in mind when you are working with gas. There will be a slight
odor of gas when you crack open a gas line. I lit the pilot light on the stove and that was that. No explosion.
I got a quote from 3 separate local businesses ranging from $400 to $700
to break an existing gas line that ran to the kitchen in order to install
a shut off valve. Neither of these exactly fit my budget, so I set out to
figure out how to do it myself.
The first thing you want to do is step back and figure out what your task
is. For me, because we are planning on remodeling our kitchen, I wanted to install
a shut off valve to the gas line going to the kitchen, otherwise when we
do the renovations in the kitchen we'd have to shut off gas to entire house!
Yes we could have simply unhooked the oven and installed a plug for 99 cents,
but a shut off valve is a good safety device to have and there is a good
chance we'll have to rearrange the gas plumbing in there anyway.
Think about what you need to do. Where are you running the gas line? Are
you going to tap into an existing line or do you already have a "T" to work
with? Are you going through walls or ceilings, etc? Try to gather up all
of the materials you need before hand. You don't want to be stuck without
heat or an oven because you can't find some obscure part. If adding a new
line, always install a shut off valve both where you split the existing
line AND at the install point of the new appliance. Furthermore, I always
recommend adding an additional port for future installations. So for example
if you are splitting an existing line into a "T", consider splitting it
into an "X" and simply putting a "plug" in the unused portion until you
need it. Next time it will turn a 1+ hour job into a 5 minute job.
Pictured above is a 3/4" gas line going to the kitchen. On the far
end by the meter it's split by a T, and close to the foreground there is
a 90 degree elbow.
1/2" and 3/4" black iron pipes are the most common size. A 1/2"
black iron pipe will be a little less than 1" on the outside diameter
and a 3/4" black iron pipe will be a little more than 1" on the
outside diameter. NOTHING on a 1/2" pipe measures 1/2" so don't
be too confused trying to figure out which is which. You can see this
page for more detailed dimensions (look under "wrought iron pipe").
One thing to mention now that we are dealing with "black iron pipe",
we suggest that you stick to either using black iron or CSST (corrugated
stainless steel tubing). There seems to be ongoing discussions about mixing
black iron and galvanized with natural gas and the consensus is to stick
to black iron. CSST is stainless steel wrapped in orange. This stuff is great. It is very easy to work with
and like the name suggests, it is flexible, making it easy to snake through
walls and ceilings. It comes in pre-determine lengths. Again, I do not recommend
galvanized or any other materials than black pipe or orange flexible
If you are not dealing with the "end" of a pipeline, remember
that because these pipes were put together sequentially, you can't just
unscrew the middle pipe (that would be too easy!) because tightening one
end will loosen the other end and vice versa! Instead what you will need
to do is cut the pipe, then replace what you have cut with a "union"
fitting, your shut off valve and correctly sized "nipples." Nipples
are pre-cut and pre-threaded pieces of black pipe that come in just about
Above is the length of pipe as it goes into the "T". Since our
pipe has a "coupling" fitting (shown at arrow), we'll cut on the
"X" and save all of the pipe to the left of the coupler. What
this means is that to the right of the coupler, where we cut out the pipe, we'll need to replace
the exact same length, but in the form of 2 nipples and a union fitting.
A union fitting is a special fitting which allows you to tighten 2 sequential
pipes which cannot be rotated.
I measured the distance between the coupler and the "T" to be
about 16", so I went to the hardware store and purchased a union fitting
along with many different sizes of nipples to be sure that I would get it
perfectly. This may take some guess work but you want to have several different
nipples in half inch increments to be sure you get a very snug fit.
While you are at the hardware store, be sure to pick up Teflon TFE paste
and leak detector. Do not settle for TFE paste without Teflon. This is the
gooey stuff that will be coated on the threads of the nipples and eliminate
any chance of a leak if properly tightened. The leak detector is essentially
a solution of soapy water which will bubble up if there are any leaks.
Another thing to think about while you are taking pipes apart is whether
or not you will ever need to expand. For me I considered installing a garage
heater in the future, so I also installed an additional "T" which
I fitted with a shut off valve, followed by a plug.
Now that we are ready to take the system apart, think about a few things.
If you are like me, you are about to cut gas out to your oven, stove, water
heater and furnace. Are you going to finish this today? Are you sure? Do
you have a back up plan? For me, my back up plan was to stick a "plug"
in the "T" which would simply plug off the gas line to the oven,
allowing me to turn back on my furnace and water heater.
Shut off all appliances that use gas. Turn off the furnace at both the thermostat,
and big red switch. If you have a gas clothes dryer, don't run it while
you are working on anything.
If you have any shut off valves, turn them all off.
Shut off valves to our furnace and clothes dryer. A shut off valve is "OFF"
when the valve petcock (handle) is perpendicular to the valve body. Closing
valve will isolate gas between valve and appliance. Some appliances, like
furnaces will need the air purged from the line if you remove all the gas
in the line. Keeping some gas in the line but isolating it with the shut
off valve may avoid this.
Corrugated stainless steel tubing (CSST) is shown in the background. CSST
is very easy to work with because it is sold in pre-cut lengths with connectors
on both ends. Furthermore, you can unscrew these gas lines at junction points
instead of having to cut them like we do with black pipe.
If you have a gas water heater, turn the knob to off.
Turn knob on water heater to off. This turns off the burner if it is going,
and also the pilot light.
Once you are sure everything is off, shut off the MAIN SHUT OFF VALVE.
Please be careful with the main valve. There is a good chance it hasn't
been turned in 50 years. Grab it with locking pliers or plumbers wrench
and very slowly, rototate the one hole until it matches up with the other
hole. This is so that the power company can put a lock on your gas line
when you don't pay your bills. There is no "stop" on this valve,
it will rotate around in circles.
Put a screwdriver in this hole. It's not going to move by itself but this
should suggest to anyone not to mess with it. You may want to put up a sign
What about the oven? Remember we don't have a shut off valve on the oven,
so AFTER we turn off the main shut off valve, we will turn on the oven and
run it until it dies. The idea by closing the other shut off valves we're
isolating gas between the valve and appliances. Since we have no shut off
valve on the oven, the idea is to clear out the line of gas.
So now, every appliance that uses gas is off, every shut off valve is off
and every appliance that doesn't have a shut off valve has been "expunged"?
For safety's sake, I like to vent all over the house by opening windows
when I am doing this. I will do it in the basement near the water heater,
kitchen near stove, etc. In this case we were cutting in the garage so I
opened up the garage door. If gas leaks out you want it to dissipate.
Secondly, everyone will recommend that you use a manual hacksaw (not electric)
because you do not want to produce any sources of ignition when cutting
a gas line, be it from the electric motor, or from sparks. To be honest
, I used a 9 amp SawZall and yes there are a few sparks. There is not enough
gas left in the pipes to do anything. If you are unsure, use a manual saw.
Above is my pipe cut. I already removed the right side in this picture.
Next, I removed the left side of cut pipe that screwed into the "coupler".
I put some duct tape on there just to keep any trace amounts of gas where
they are; not really necessary.
Here comes the importance of PLUMBERS WRENCHES. You need TWO plumbers wrenches
to do this job. Do not try to do it with locking pliers or anything else.
Get wrenches that are appropriate to the size of pipe and amount of room
you have to move them. Please think about the amount of money you are saving
and spend the $10-$15 each on the wrenches. The grasp and amount of leverage
you have is very important.
I decided to put the shut off valve closer to the kitchen. It makes sense
to put the valve as close to the appliance as possible. In the first picture
above, I put it right before the 90 degree elbow.
Generously coat the threads of the pipes with teflon TFE paste. Try not
to get TFE paste on the inside of the pipe. Screw in the pipe very tightly
using 2 plumbers wrenches. You can wipe away excess TFE paste now. The TFE
paste will harden.
When installing the union, take the union apart and you will notice it has
3 parts. 2 female fittings and the large union nut. Without re-arranging
the parts, slide the huge union nut down the pipe that will receive one
of the female fittings to get it out of the way. Attach the female pipe
fittings to each of the left and right nipples. Then, place them together.
This may and should require very gently moving the pipes a little bit. Slide
the the large union nut into place and tighten completely. You do not
need TFE paste on that. If you cannot get the 2 female fittings of the union
to touch each other, you need to change sizes of your nipples until they
On the left is the old coupler. We put a new nipple into that. On the far
right (not shown) was the existing "T". We put a short nipple
into that, then we attached a new "T" fitting which has a 3rd
port which faces the wall for future use.
Now that you think everything is on there well, and your new shut off valve
is closed, turn the main valve back on. With your leak detector solution,
spray generously everywhere A) that you just installed and B) anything you
may have disturbed in the process including old existing connections and
watch carefully. If you are wondering what to look for, please check Komar.org's
gas leak detector page.
Remember that natural gas has a pungent odor to it. Smell carefully for
this odor and don't confuse the odor of TFE post or iron piping with the
smell of gas. It should be very obvious. If you are sure that there is no
leak, continue by opening your individual shut off valves and turning the
appliances back on one by one. I would suggest opening a valve, then turning
on the appliance. Not opening all valves and then turning on all appliances.
Do not forget that some appliances will need special attention. A gas powered
water heater with no electrical connection will require you to light the
pilot light, as will our old oven. Close all of your windows and monitor your house for smells especially the area where you have added or modified any connections.
You may want to pressure test any new connections but please beware that shut off valves are only good to 0.5 PSI and CSST tubing only 5.0
On March 13, 2008, 1:44 pm test said:
On March 13, 2008, 1:44 pm Mark said:
Greetings. I found your article very informative. Who knew working with gas pipes could be so easy? ;)