While replacing my natural gas water heater, I discovered the main gas line entering my house was bent. An electrical wire going to the furnace had been attached with black tape to the line so the bend had been hidden from view since we bought the house 6 years ago. I would appreciate your opinion as to whether this should be a concern and whether it should be repaired or left alone. Also, if it should be repaired, what options are there to splice the main natural gas line? Does the entire line to the outside need to be replaced?

Image are attached.





Thank you!

 

In my area it is a code violation to use copper for natural gas. You should check with your inspection department. Even if they say copper is okay gas piping is best left to the pros. The pros here will be along later to give you more detailed advice.

 

I would replace the entire copper line. Since the pipe is damaged, it must be replaced pronto.

Copper, while perhaps permissible in some locations, is not ideal for natural gas. Sulfur in the gas, depending upon its concentration, can degrade the copper. There are approved flexible gas lines that can be used to supply appliances that may need flexibility, but normally not a water heater. Whoever installed that piping is a criminal, in my opinion.

I would replace it with black-steel, threaded pipe. You may need to call a plumber, because the steel pipe may need to be cut and threaded to fit - beyond just buying assorted nipples and fittings at the hardware store. After you get through paying the plumber, it might approach the cost if he had also sold you a replacement water heater?

What other copper gas piping do you have in the house?

If the gas company needs to come into your house for any reason - such as for a reported gas leak, to relight pilots after an outage, or a meter change-out, they will do a cursory inspection and lock out your gas service until it is corrected and re-inspected. Fix it all now.

 

Continuous soft copper is almost always used in houses for natural gas and propane in Minnesota, and has been for the past 30 years or so. The only time I see black pipe used now days is for making the final connections to appliances, and risers at appliances. It is very common to even come off the gas meter with copper.

IMO that dent is not a big deal. Also, if it was worse, it can be repaired with a coupling that is properly brazed on (not soldered on). An HVAC company, or perhaps a plumbe,r can fix it you are leery about it.

 

Isn't it amazing.... different codes in different areas. As far as I know.... here in NJ soft copper is not used for inside gas work.

 

The National Fuel Gas Code (NFPA 54, ANSI Z223.1) covers piping and joining methods for natural gas. Like other such standards, they are applied when and as adopted by the local jurisdiction, which gives rise to local differences.

NFPA 54 was developed in cooperation with the American Gas Association, the trade association of gas distribution companies in the U.S. Copper pipe is allowed if the gas contains less than 0.3 grains of hydrogen sulfide (0.7 mg/100L). Your gas company can tell you what the sulfide concentration is now, but in the future the company's source of natural gas could change - with an increase in sulfide. Where we live, the local gas company has changed hands at least three times, but who knows about the actual gas source in the future?

Interestingly, when our buried service line was originally installed, it was steel, coated and wrapped. The gas company's standards changed, and the steel pipe was replaced with copper. Now, copper is no longer used, and it has been replaced with plastic. This is the service line ahead of the meter, which is under the purview of the gas company, not inside the house - but it demonstrates how standards evolve.

NFPA 54 prohibits the use of copper fittings with steel pipe. Fittings that transition from steel to copper, or vice versa, must be brass or bronze.

In my area, only black steel pipe is used for natural gas inside residences.

 

WI is like MN - copper for gas is common and my house is piped pretty much as Tolyn describes.

 

The dent can cause reduced gas volume..

The only way to repair is to cut the dent out and use a flare coupling to join back togther...

This will work if you have some play in the pipe..

After line is cut slip the nut on each end of pipe and flare...

 

Thank you all for weighing in, very insightful. I think I'll go ahead and have a professional out to repair that section. Better safe than sorry.

 

Let us know how it turns out..

 

I had a professional look at it. They recommended leaving it as is...

 

>


I agree.


Most fuel lines are significantly oversized for the load they see. A dent like that will make no difference in the gas pressure the appliances see.

 

I disagree.. You cant make any determination unless a gas calculation is done..

Starving appliances for gas causes sooting and probably CO issues...

 

>



Turn all the appliances on and measure the gas pressure at the appliances. BETTER than a gas calculation.

And I would bet that about 99% of gas installations have extra capacity in the piping system.


In my experience as a gas utility repairman, it was VERY unusual to find a gas piping system that was undersized enough to affect appliance operation.

The most dramatic example of that was in a large, old apartment building where the only gas appliances were a range in each apartment.

The management had replaced the central heating and HW systems with a gas furnace and gas water heater tio each apartment, using the 1/2" gas line that had served the gas range and went down to the meter room in the basement.

The apartment building had had many service calls about appliances not operating properly. I wound up putting recording manometer on the gas supply side, which showed that the gas supply pressure TO the gas meters dropped sharply in the morning and evening when the gas appliances were used.

The utility wound up installing a new service was increased gas supply to the meter room, which solved the problem. The original 1/2" fuel lines were still adequate to providing gas to two additional appliances in each apartment.