Black Iron Pipe To Galvanized Pipe

[BigGarage]

If I do one more project this year it will be to replace the old galvanized steel gas lines in the house. I have an underground line that runs out to the garage though. It's not been used in many years but I do have a 30-40000 btu heater out there and I use propane (separate propane heaters) in the winter for heat if I'm working out there. I may want to use the natural gas heater one day instead and save trips to the propane store.

Is there an acceptable (codewise) method for coupling the new black pipe to the old galvanized pipe?

Dennis

 

[sberry]

Common fittings.

 

[The Cobbler]

as said above, but, I would question the condition of the buried steel pipe before you get anxious about using it.
isolate it & do a 100psi test on it .

 

[SGKent]

I've seen underground steel gas pipe rot in as few as 7 years. In reasonably dry soil too.

 

[sberry]

I agree about the steel underground, replace it with rolled copper.

 

[bob15]

I would run the copper tubing inside PVC pipe. This will protect the copper tubing.......

Of course, check with your local reg's first. It was legal for me.

 

[rustyjames]

I think natural gas lines are commonly done with plastic.

 

[LS6 Tommy]

I agree about the steel underground, replace it with rolled copper.

Check your codes. You can't use copper with natgas if it contains more than .3 grains of Hydrogen Sulfide per 100 cubic feet of gas unless it's treated for that use.

Tommy

 

[The Cobbler]

HDPE is the standard underground gas pipe now

 

[Copymutt]

Back when I plumbed my garage, 1995 Scotchcoat was code for buried pipe.

 

[John in OH]

HDPE is the standard underground gas pipe now

I think this is correct. About 3 years ago I had gas service installed to my house and ALL the piping from the main to the distribution line to the house line was all yellow plastic. I guess it was HDPE but I don't know remember for sure.

 

[Stuart in MN]

As you may have guessed from the responses so far, there are number of different types of gas line possible but it will depend on what is common practice in your area, as well as what the local gas company requires. Ask them.

isolate it & do a 100psi test on it .

Natural gas lines typically are ~2psi coming from the street, and 1/2 psi or less on your side of the gas meter. 100psi seems excessive.

 

[The Cobbler]

. 100psi seems excessive.

yes, but if the pipe is weak, it would let go is all I was thinking .
my underground HDPE had to be tested at 50 psi if I recall correctly

 

[mrobins297aaa]

As you may have guessed from the responses so far, there are number of different types of gas line possible but it will depend on what is common practice in your area, as well as what the local gas company requires. Ask them.



Natural gas lines typically are ~2psi coming from the street, and 1/2 psi or less on your side of the gas meter. 100psi seems excessive.

I agree that just creates leaks that you would not normally have

 

[HoosierMark]

In the city where I live the local gas company (city owned) sells the contractor or homeowner the length of yellow flexible gas line they need and will install one fitting on it for free (no labor). Will do both if you are sure of your length. Their theory is that safety is important and provide the residents with what we use at cost is a good idea.

 

[BigGarage]

Common fittings.

Are you telling me the connector fittings are the same? I thought black iron gas lines were tapered some and may have needed something special.

I do not know anything much about gas lines. Thanks.

Dennis

 

[BigGarage]

as said above, but, I would question the condition of the buried steel pipe before you get anxious about using it.
isolate it & do a 100psi test on it .

The gas valve from the house to the garage is open and has been for probably 50-60 years. I have never smelled gas out there. It's about 20' from the house to the garage and I have a garden there so much time is spent in that area. No gas smell ever. If I ever smelled gas I could shut it off in the basement and decide what to do. I was just trying to avoid running a new underground line under a sidewalk (3' wide) if I could.

Dennis

 

[gmwelder86]

Standard test for low pressure gas pipe is 15 pounds for 15 minutes. Residential gas operated at les than .5 psi. Testing at 15 pounds your going to find any issues if you have them. Now medium and high pressure welded systems that’s different.

If the old system is working well and doesn’t leak why mess with it. I’ve found once you start messing with old black pipe systems weather it’s gas or water, once you start you might as well take it all the way back to the meter.

 

[mrobins297aaa]

The gas valve from the house to the garage is open and has been for probably 50-60 years. I have never smelled gas out there. It's about 20' from the house to the garage and I have a garden there so much time is spent in that area. No gas smell ever. If I ever smelled gas I could shut it off in the basement and decide what to do. I was just trying to avoid running a new underground line under a sidewalk (3' wide) if I could.

Dennis

Here's a easy way to check it.
Make sure no gas appliances are running.
Now go out to the meter and mark with a pencil the position of the needle on the most sensitive dial......come back in a half hour and see if the needle has moved at all........if it hasn't moved your good.
if it has then start turning off the valves on the individual appliances to see if you can locate it.

edit: now if you happen to have any standing pilot appliances you will have to valve them off for this to work

 

[mrobins297aaa]

Are you telling me the connector fittings are the same? I thought black iron gas lines were tapered some and may have needed something special.

I do not know anything much about gas lines. Thanks.

Dennis

The pipe and fittings are all the same, there are plenty of systems out there that have a mix of galv and black pipe.

 

[BigGarage]

If the old system is working well and doesn’t leak why mess with it. I’ve found once you start messing with old black pipe systems weather it’s gas or water, once you start you might as well take it all the way back to the meter.

I understand and mostly agree with you but there is a scary looking gas valve down there in basement and I'd like it gone. I could just remove it and put a plug there and leave it. The valve most likely controlled gas to the old original steam furnace with radiators.

The valve looks like an extra large gate valve. I'm sure it was gas rated but its just at the end of a line coming down a few feet from the ceiling and it just needs to be removed. It does have a plug at the end of it but it scares me just looking at it.

I would replace all of the piping back to the meter so I'm clear on that. I just wanted to know if I could leave the line going underground to garage and tie into it.

I just went down and looked at the valve and noticed that the installers of my boiler (in January) used black iron pipe to connect to the original pipe. Unless my eyes are playing tricks on me.

I would have a qualified person do the work, I would not do it myself.

Dennis

 

[mrobins297aaa]

one more thing, years ago in Detriot there was a code that you couldn't use galv. pipe on gas lines.
Not sure why, one theory was that the galv. would flake off and plug the orifices on the appliances.......which I always found it hard to believe.

But a much more likely reason was that back in the 40's and 50's all the water pipe was galv. so they didn't want someone cutting into a galv pipe thinking it was water and they were actually cutting into a gas line. So it made sense, black for gas, galv. for water.

 

[BigGarage]

Here are 2 pics of the gas valves in the basement and one pic of a union on the line going to the garage.

If the knowledgeable people don't have a problem with these items I may leave them alone.

Dennis

 

[BigGarage]

one more thing, years ago in Detriot there was a code that you couldn't use galv. pipe on gas lines.
Not sure why, one theory was that the galv. would flake off and plug the orifices on the appliances.......which I always found it hard to believe.

A boiler installer about 15 years ago told me the same thing. He would stop by every so often and get an extremely small stainless steel needle from me to unplug orifices with. He was 75 and knew his stuff.

Dennis

 

[mrobins297aaa]

well maybe there is some truth to it but you can't prove it by me, now days there's a lot of galv. pipe and fittings being used on gas and I have not heard of one service guy saying he's running into that problem.
lots of places don't even sell black pipe and fittings anymore only galv.

 

[The Cobbler]

Here 2 pics of the gas valves in the basement and one pic of a union on the line going to the garage.

If the knowledgeable people don't have a problem with these items I may leave them alone.

Dennis

I would be very surprised if those valves are rated for natural gas.

 

[mrobins297aaa]

I would be very surprised if those valves are rated for natural gas.

you might be right, there looks to be enough writing on them you could probably look it up and see.

 

[BigGarage]

The pipe and fittings are all the same, there are plenty of systems out there that have a mix of galv and black pipe.

I overlooked this response this morning. Thank you.

 

[The Cobbler]

I would be very surprised if those valves are rated for natural gas.

you might be right, there looks to be enough writing on them you could probably look it up and see.

as far as I know, bushings cannot be used in gas lines either ( pic 2)

 

[BigGarage]

I would be very surprised if those valves are rated for natural gas.

I will try to find out. Have to go to work now. Thank you.

Dennis

 

[buzzworth]

Galvanized should not be used for gas. The valves are suspect for gas, look like globe valves. Even old gas valves are quarter turn.
And the use of a bushing in the valve would not meet code here.

(Former supply house sales)