Thread: Copper natural gas lines

I came across an interesting article talking about copper natural gas lines and whether they are acceptable. I scanned the article from "The Family Handyman".

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I think one of the problems is this. Iron piping is acceptable now. If you you add copper to the list, then you'll have knuckleheads mixing materials. Then, you'll surely run into problems.

The National Fuel Gas Code (NFPA 54/ANSI Z223.1) and all of the major model building codes have approved copper for the use in fuel gas systems. In fact, in states like Minnesota, Alabama, Georgia, Florida, etc, copper is the dominant, if not the primary choice, for flexible fuel gas piping systems in homes and multi-family units. IAPMO approved copper for use with fuel gas in 1999.

In certain areas of the country it has been against the code to install copper tube for natural gas distribution. This was primarily in areas of the country that utilized the Uniform Plumbing Code, predominately in the West, and most actively in California.

However, at that same time many other areas of the country were successfully installing copper tube in both natural gas and LP gas distribution systems. Many of these areas have been installing copper tube for natural gas distribution for better than 35 - 40 years (Minnesota, St. Louis, Atlanta, Washington D.C. among others) and for most of the country copper tube has been the standard material for LP gas distribution much longer than that.

In the beginning, the reason for this disparity throughout the country in the acceptance of copper tube for this use had to do with the gas being supplied. In the southwest area of the country sour gas (gas containing a significant amount of hydrogen sulfide) was not uncommon, and the use of copper tube in a gas stream containing significant amounts of hydrogen sulfide and moisture lead to the black flakes to which you refer. It should be noted that this was generally encountered in natural gas systems, not LP gas systems (LP being a manufactured gas was more closely controlled with regards to contaminants). However, in the rest of the country the natural gas being supplied did not contain such high concentrations of hydrogen sulfide, allowing for the successful use of copper tube. This was reflected in the codes and standards used throughout the rest of the country allowing copper tube for this use (such as the NFPA 54 National Fuel Gas Code, the BOCA National Mechanical Code and the SBCCI Standard Mechanical Code).

In the last 35 - 40 years, the cleaning and distribution of natural gas throughout the country has improved greatly, especially with the development of regulations strictly limiting the amount of hydrogen sulfide and other contaminants that could be distributed in the gas stream, especially for those gases being supplied over nationwide, inter-linked gas distribution pipelines/systems. These regulations limit the hydrogen sulfide to such a level that it should no longer be available in large enough quantities to promote the black flaking that you had seen in the past.

Recognizing this fact, and the fact that the use of copper tube for the natural gas distribution system allowed gas utilities and building owners to provide natural gas as a cost effective alternate energy source to electric, has led many areas of the country that previously banned the use of copper in this use to reevaluate their position. Most notably, the Pacific northwest (Oregon and Washington especially) have recently begun to aggressively promote and use copper tube for their natural gas distribution systems, regardless of the restriction in the Uniform Plumbing Code.

Following suit, IAPMO, through the use of the consensus process voted to change the Uniform Plumbing Code to lift the restriction on the use of copper tube for fuel gas distribution systems. These changes were published in the 2000 edition of the UPC and UMC.

However, since all natural gas supplies are not necessarily delivered via pipelines regulated by the above regulations, all of the codes allowing for the use of copper in natural gas distribution systems do contain the restriction that bare copper tube not be used if the gas stream contains an average of more than 0.3 grains of hydrogen sulfide per 100 standard cubic feet of gas. Should the gas stream exceed this amount, the codes permit the use of copper tubing if the tube is tin-lined. These requirements are in place to minimize the possibility of flaking inside the copper and to ensure an efficient and successful use of copper tube for this application.

So as far as long term use is the tin going to be flaking off like with what used to happen with the older galvy pipe?

http://www.copper.org/Applications/f...nal_report.pdf

From the report AD posted:

It was clear that bare copper tubing was susceptible to corrosion when exposed to
distribution gas in the Pico Rivera service area. Corrosion products formed on the surface
were friable and easily broke away from tubing wall. The amount of corrosion products
trapped in the filter downstream did not clog or restrict gas flow. Nonetheless, the
quantity of corrosion products generated in the foot-long sample did not represent the
actual amount that could form in a typical house line. With longer lengths of bare copper
tubing, as would be installed in a typical system, it is likely that a greater quantity of
corrosion products would form and be available for transport downstream through the
piping system. Based on the scope and results of this testing, it is not possible to project
the quantity of corrosion products and the potential to cause blockage at orifices in
valves, regulators, etc.

I think I will stick with my recommendation that copper tubing should not be used on natural gas piping. This is especially true since the standard installation in the area excludes sediment traps.
It has always been true that it takes a long time for pinholes to develop due to corrosion but I have been around long enough to see pilot light orifices clogged from corrosion of copper tubing used as flex connectors. And that is on Texas natural gas which by most accounts is pretty clean and dry, although I'm not sure what the concentration of corrosive ingredients are now or in the past.

Two questions:
What is the black flaking spoken of? If it is Cu hyd/sulfide corrosion or any chemical combination using the copper to make such, then shouldn't all tubing used for this purpose be tin lined for safety's sake?

What if any, are the requirements for physical protection of the tubing?
Not my field of study, so please use lots of lube...
Bob Smit, County Electrical Inspector

According to the 2003 IRC G2414.5, copper is only allowed "to be used with gases not corrosive to such material"
I don't have the latest code at hand but I suspect it has not changed much.

G2414.5.2 specifies that Copper and brass tubing shall not be used if the gas contains more than an average of 0.3 grains of hydrogen sulfide per 100 standard cubic feet of gas.

The standard in my area disallows the use of copper on natural gas and I plan on keeping that my standard until proven that it is OK and that sediment traps are installed.
Given the price of copper and the availability of CSST, I doubt it will be much of an issue for new construction and most of the existing already has problems that should be dealt with.

Bob, the black flakes or dust is copper sulphide and has been well documented with the fire investigation, gas and insurance/ loss industries. Most evidence points to a very low incidence rate at exposures under 0.3 gr H2S, thus the code reference. You would need to contact your local utility for information on the acceptability of copper tubing with their product but good luck getting anything in writing.

The Handbook at Copper.org is the best single resource for the use of copper tubing and is a national standard referenced in court. It includes 'recommendations' for proper protection, support, joints, etc. For instance, no pipe dope on flare fittings.

The code requires sediment traps whether the AHJ inspects for them or not just like your Std of Practice requires certain key points whether you choose to include them or not. TREC, which is highly prescriptive, is a special case because it doesn't always jive with the codes.

You can easily make a sediment trap using semi-rigid copper tubing. Imagine the copper tubing coming down to a furnace, boiler or water heater. You install a listed ball cock shutoff using a flare to the tubing within 6ft of the appliance. Then add a sufficient length of tubing with flares to the discharge of the gas cock and the other end to a flare tee. The snout of the tee goes to the appliance valve. It will need a grommet where it penetrates the appliance cabinet or attach to a black iron nipple if required locally. The bottom of the tee has a 3" length with a flare cap to form the trap--done. Flare tees are available at most HVAC supply houses in 3/8 and 1/2". I would not recommend a 3/8" line to any appliance except hearth appliances or those with low BTU input ratings--see the sizing charts in the code. With flares, you should not need a ground union to the appliance.

Internally tinned copper tubing is getting harder to find. Best bet is to use a dedicated type L tubing with yellow polyethylene jacket labeled for gas. This protects and identifies it. Natural Gas & LP/Gas Coated Copper Tubing

HTH,
Bob

Given the price of copper and the availability of CSST, I doubt it will be much of an issue for new construction and most of the existing already has problems that should be dealt with.

JL: CSST is a system with lots of unresolved safety issues. If you are not spending about a quarter of an ink cartridge informing your clients of this, you are remiss.

Hi, All &

So -- really depends on where you are /where that fuel is sourced, it seems...

'Up here' (B. C., Canada), at least in the Vancouver south coast general area, both have been used for years and still are, for what that's worth ?


CHEERS !

Thanks for the info.
I have done a fair amount of plumbing water & gas over the years, but do respect my limitations.
Reasons for my inquiries; I did an electrical job for a neighbor in trade for a small gas-fired heater for my (garage) machine shop.
Every bit of wall space is taken with machinery and shelving etc. etc.
I sectioned off a room where my boiler and air compressor reside.
Haven't installed said furnace because would be impossible to run pipe without moving literally tons of stuff. If I may run copper tubing, mechanically protected, utilizing only flare and/or threaded connections, I should be safe (all codes applied also). Am I correct?
Bob Smit

Both copper and CSST make me imagine fires/explosions due to punctures or, in the case of copper, galvanic action. CSST just seems so flimsey (sp?) compared to iron. Damn the cost, full speed ahead. Don't need to test if your gun's loaded by pointing it @ someone & pulling the trigger.

Oddly though, both copper & CSST might fare better in an earth quake.

Originally Posted by A.D. Miller

JL: CSST is a system with lots of unresolved safety issues. If you are not spending about a quarter of an ink cartridge informing your clients of this, you are remiss.

Standard comment on CSST informs of ligation and lightening risks and a call for bonding since none of it outside of Frisco is ever bonded.
AD have you (or anyone else) seen any of the flow sensing shutoff valves (sorry, the real name escapes me) yet?

Originally Posted by Jim Luttrall

Standard comment on CSST informs of ligation and lightening risks and a call for bonding since none of it outside of Frisco is ever bonded.
AD have you (or anyone else) seen any of the flow sensing shutoff valves (sorry, the real name escapes me) yet?

Excess Flow Valves have been used in industrial and commercial buildings for years. They are starting to gain popularity in residential applications but are not required yet,,Key word yet. Most likely is use on LP systems.

As for CSST, I have used it for years and never had a call back, and bonding is highly enforced here in CT.