Anyone here work on residential gas lines?

i want to replace mine. Lots of reasons..... bad layout from piecemeal ad ins, age, and a buried Lin from the house out to a spot next to my shed that I keep tripping on. I asked a plumber to look at it. He gave a big number, said he hates crawlspaces, and doesn't want to use iron pipe. 

He said if I really want iron I should do it myself. Apparently no one in the profession wants to mess with non plastic runs. I am sure I can build a sufficient run back, but my concern is how to remove/ join to the old. I have read the INC fuel gas code and feel comfy that what I add will be right, but I am always open to new knowledge.

My current thought is:

disconect all my appliances and shut the valves

connect my mig gas tank to a spigot fitting by my fireplace, open the valve by the garage, and slowly pump the mig gas in while the flammable stuff goes out. Slowly do I don't create a huge cloud in my hood.

once I stop smelling eggs, hack saw the existing pipe after the meter but still outside. Instal a valve.

turn on the gas at the meter and check the valve connection for leaks. Repair as needed till it is holding.

build my new service lines from the new valve all the way out to the appliance service valves. Cap all these lines past the valve and pressure test the assembly to 15psi. Check for bubbles at joints. 

When it holds pressure for 2 hours and no leaks are found purge the pressure, remove the caps. Attach the appliance lines and turn on the meter valve and the revive valve I added.

refire water heater pilot.

is there anything I am missing? Any steps that are overkill?

What exactly are you hacksawing?  Is there a union after the meter that you can thread new into?  I've done this in my profession from adding one appliance to replumbing from the meter in.  The argon bottle is overkill, I usually use air from a blow gun with a rubber tip to seal.  

I have started using the flexible stainless with the yellow plastic coating for appliance runs in the last couple years and that makes life so much easier.  

The easiest way i have found to check pressure holding is a bicycle foot pump with a gauge, and i have a series of adapters with a schrader valve that i can hook to the main line.  Hook bike pump up, pump to 2-3psi, gauge will show leakdown if it exists.  I tried to get a real tester when out of town in a small vacation area and that was all i could find, and have been using it ever since

I ran a black iron gas pipe across the house once for a gas line for our new dryer.   

A lot of work as we used a pipe threader too.  We prayed at the we had no leaks because you can really only work from one end to the other.  

Yea. I've done threading in a previous summer job. Not doing that here. I will pay the premium for pre threaded....

Also, your home store will thread for you.  I use a local hardware store and they take my list and give me finished pieces, and only charge me for every 10' section used.  Home derpot has threaders   

Ooh good tip. I didn't know they did that

Just had natural gas installed a couple months ago.  All the piping after it got thru the wall is flexible stainless with a rubber covering.  I asked the guy from the gas company, the plumbers who did the inside work, and the city inspector about black iron pipe.  In all cases the answer was "We don't do it that way anymore".

Corrugated stainless steel tubing (CSST) is the new standard in gas supply.  Systems include manifolds, fittings and valves for all kinds of situations. It uses a crimp tool to make connections, and has to be done right, so it requires a licensed plumber to install it.  There are plastic lines out there as well, but I would never use them. 

Another reason is that sizing a gas supply is critical to avoid insufficient gas supply to major appliances.  This is deadly, very very deadly.  Plumbers measure all distances and size lines accordingly to ensure proper supply pressure and flow, especially at the ends of runs.  If you don't know how to calculate and size runs properly, hire someone who does.  A furnace not getting enough gas will kill everyone in the house, I cannot stress this enough.  Read a lot about Sizing Gas Lines before you rip everything out and start from scratch. This applies no matter what type of supply lines you are using.  

Lastly, don't reuse the flexible connectors that hook up to your dryer, oven, water heater, etc.  These are designed to be used once.  Once you disconnect the flare fittings, they are compromised and won't seal as well and must be replaced.  Don't cheap out for the last 2 feet, replace the connectors.  

I used to work for a gas-connector manufacturer and was involved in CSA safety standards (yes, the Canadians set the safety standards for gas worldwide) so I have a little knowledge here.  

I don't need to re-do a whole house, but I do need to re-do a short run to my dryer that some fool used copper pipe for rather than black pipe.

But the house has been in our family for 20-25 years and it has been holding at least all that time so it can't be all bad.

pinchvalve said:

Another reason is that sizing a gas supply is critical to avoid insufficient gas supply to major appliances.  This is deadly, very very deadly.  Plumbers measure all distances and size lines accordingly to ensure proper supply pressure and flow, especially at the ends of runs.  

Yes, when I asked questions about the type of pipe I also got educated about using the proper pipe size.  Way too complicated for me, so I was happy to let the plumber figure it out.

My F-I-Laws neighbor was selling his home and the inspector found an issue with the water heater.  

Somebody had connected two flexible lines together to run gas to the water heater.  LOL.  

Licensed master plumber here.  I'd run black iron over CSST any day.  Seen way too many issues after the install with CSST leaking.  Those fittings have a way of loosening up.  Plus theres the whole bonding it to protect against lighting strikes, which can cause it to melt and start a nice gas fueled fire.  There are some instances where you have to run CSST, but if faced with a job that required such, I walk away from the job.  I'm certified to work with CSST.  I'll make repairs to it, but I won't install it.

Tr8todd - interesting comments.   My dads house was built in 1970 and the building code was copper pipe in and out.   He had 4" copper pipe running across the basement and when he sold in 2014 he can say he never touched any of the plumbing or gas lines in 44 years short of a few faucets.   (Although I do believe PVC is okay).  

Some of the new technology is good, some is just a lazy mans way out.  Recently approved is a system that uses black pipe, but instead of threading the pipe, its crimped.  Goes faster because you cut the pipe, slide on the fitting and then a power tool crimps the fitting on to the pipe.  Fittings are more expensive, tools are expensive, and you need a head for each diameter pipe.  You can't reuse the fittings, so if something changes, you have to cut out the fitting and use new ones.  Not a fan of that system either, nor am I a fan of any PEX tubing that uses metal crimp rings.  The advantage to theses systems are speed, and an apprentice can install as fast as a 30 year plumber could.  The disadvantage is you are relying on an O ring to make the seal, and any future work to the system means your basically screwed unless you have access to the pro press.  One big advantage to the water piping system is the fact that you can crimp onto a pipe that is still dripping.  Comes in handy in a large building or where there is a questionable shutoff, but there are other solutions to this as well.

Thanks everybody. I appreciate the advice.

i am still planning on black pipe and fittings. Sizing pipe isnt a big concern. I'm using at least as big a line diameter as is already there and I've double checked it with the tables in the fuel gas code and kept it one size bigger than needed throughout just in case I add on and / or need bigger appliances in the future.

one last question though. Researching has indicated that some service valves are not good for more than 5 psi. That seems ok for normal service loads, but are there higher ones available for the main cutoff I was planning? I'd like to exceed 15 psi to help with the line pressure testing. And How would I identify the highest quality valves? Are some better than others?

Question on the main cut off you're planning: isn't there already a shutoff at the gas meter? If so wouldn't that suffice for your purposes? 

The test rig should be in front of gas company lockout,outside of structure, last connection made. Most residential appliances run on ounces of pressure. Be very meticulous here or you will make the evening news. Done much plumbing?

You only need to test it to 3psi.  I test to 5 psi.  If there is a leak, you'll know within the 15 minute required test time.  Don't trust the valves to hold test pressure.  Disconnect the appliance and cap the line for a test.  Most leaks are at the valve handles or at any unions.  If you come across one of those old brass shutoffs with the square head for a shutoff, replace it with a new valve with a Tee handle.  Those old ones rely on grease inside the valve to make the seal.  Working pressure is only .5 psi in a residential system.  Thats why you need to take into consideration length of piping and number of 90* bends when sizing, and not just BTU demand of the fixture.

Done a crap ton of plumbing. Otherwise we wouldn't be having this discussion. I know not to pressure test at the appliance valves. Fixed caps beyond the valve and valve open. 

That is actually why I'm asking about a better valve for the main cut off. The meter does have a service cut off but everything I have read says don't load the service meter past 5 psi. I DONT want to be on the news so I want to pressure test beyond that.

Disconnect the union at the outlet side of the meter.  Unscrew the swan neck piece that the meter hangs from.  That will leave you with a female opening at the very beginning of your gas line going into the house.  Install your test gauge there.  If you want to add a whole house shutoff just inside the foundation, go ahead.  You don't need it, but its not a bad idea.  Any commercially available gas valve will be fine or else it wouldn't be approved.  Just make sure it has the Tee handle, because thats the code.  Not always adhered to, but code none the less.  Your test rig should have a nipple going into a tee.  One end of the tee gets a shraider valve to pump it up, and the other opening in the tee gets a gauge.  Just pick up a 7# gauge and make sure you can read tenths of a pound on the gauge.  Don't go get a 100# well gauge and expect to see a leak in a 15 minute test.