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Galvanized pipng for gas

Hi,  I was taught this is bad news.  Apparently our local gas company, Nicor, is planning on starting to use it.  Any comments?
The Steam Whisperer (Formerly Boilerpro)

Chicago's Steam Heating Expert

Noisy Radiators are a Cry for Help


  • Steve MinnichSteve Minnich Posts: 2,474Member
    I was taught the same thing

    and I believe it's because the coating on galvanized tends to flake and potentially clog orifices, etc.
    PHC News Columnist
    Minnich Hydronic Consulting & Design
  • TechmanTechman Posts: 2,144Member
    Gas pipe

    Hi! I was taught galv pipe outside, black or galv
  • GordoGordo Posts: 698Member
    Galvanized Piping and Fittings

     I have a plumbing book from 1918 that recommends galvanized fittings for gas because the zinc coating on the fittings will cover over any sand hole leaks. 

    And those were good ol' 'mercan sand holes, too!  The Middle Kingdom back then was still in the middle ages.

    In my house, built in 1968, the gas fittings are galvanized.  It was local code by then that you MUST used galvanized fittings. Now, it is condemned. Or so it seems.

    I worry not that the zinc flakes will cause problems.  Should I worry?

    Can anybody -anybody- quote a study showing where a zinc flake caused a problem with a gas valve? 

    Where did that idea come from?

    Please tell me.
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
  • icesailoricesailor Posts: 7,265Member
    Galvanized Gas:

    In 1967, when I was taking study courses for my Massachusetts Journeyman's License, the instructor told us "No Galvanized On Gas". For the very reasons you listed. That it would cover up sand holes in gas fittings. And gas pipe because if there was a leak, it was usually on the Skelp of the pipe. The instructor, a UA member and a Voke Plumbing teacher, also said that you had to be aware of hackaroos using electrical conduit for gas pipe. And if anyone has ever used HW conduit on water pipe, it leaks like a squirt gun because the skelp isn't pressure tight from the inside out. Its only to protect the wires, inside.

  • HenryHenry Posts: 914Member

    NFPA54 as well as B149.1 permits any ASTM A 53 or ASTM A 106 steel pipe  black or hot-dipped zinc coated pipe. Your AHJ can decide otherwise.
  • JackJack Posts: 1,044Member
    In my apprenticeship

    we were instructed to avoid it due to flakes getting lodged in the gas valve. Using galvie fittings to "cover up" a sand hole? I think I would prefer to have the sand hole make its presence known right away other than 30 days after I am gone.
  • GordoGordo Posts: 698Member
    Sand Holes

    The reference I quoted for using galvanized fittings for gas pipe because it seals the sand holes is from 1918.  It was quoted for informational purposes only. 

    I was trying to show some history as to the whys and wherefores.

    I am NOT advocating their use or condemning their use for that purpose.

    My point is, other than quoting "in my apprenticeship course we were instructed...",  I would like to know of any authoritative, scientific reason that can be given for NOT using galvanized fittings?

    I too, was told the same thing about the galvanized flake theory in my apprenticeship course.  Is it true? 

    I think it might be a bunch of hokum.

    I have asked this question several times on this board and no one yet has provided a hint of a good history of any gas valve leaks or failures that can be laid at the feet of zinc particles.

    We just today took apart some old gas pipe, mostly galvanized fittings, that was going to a stove on the second floor of an old house.

    There were no zinc flakes.  Why?  Because the old gas fitter had re-used fittings from a domestic water supply and were full of rust!  He is now beyond our justice.

    The old steel piping was free of rust, so it wasn't "wet gas". 

    I would say rust flakes were and still are a bigger issue than the possibly mythical zinc flakes.

    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
  • GordoGordo Posts: 698Member
    Thank You, Sir

    Does hydrogen sulfide attack zinc?  What is the result?

    Years ago, our local AHJ forbade copper for gas due to the evils of hydrogen sulfide. Than it was allowed, mostly to allow builders to put in cheaper 2 pound gas systems with small diameter soft copper before CSST became common.

    I have seen old steel gas pipe almost totally occluded with fine dust rust, so I can well imagine the vile black dust of cupric sulfide clogging gas valves.  You make it very vivid.

    Again, I am not so sure that a flake or two of zinc could cause the same havoc.

    Am I wrong? 

    Your comment about urban legends and so forth is so true.

    I well remember being told by a master plumber, who is now a Dead Man, that galvanized fittings were used with black steel pipe because it made identifying gas lines easier!

    "See? It's like a zebra. There. Black. White. Black. White. That's gas pipe right there."

    I'm not making this up.

    It is only years later I found out it was to reduce leaks from sand holes.

    And your comment about draft (death) hoods is also right on the mark!

    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
  • TechmanTechman Posts: 2,144Member
    Galvanized pipe

    If not for gas, then what is galv pipe and fitting used for? We also were taught that copper had no place in gas systems.
  • GordoGordo Posts: 698Member
    For Your In-Depth Response

    I thank you. This is good info.


    I've seen those "sediment traps" on some really old parts of the gas grid here in Baltimore.

    I was told by the "old timers" that used to haunt BGE that they would have to empty those traps periodically and the stuff that came out was pure evil. 

    I've been told that they used to shoot steam into the lines to add moisture to keep the hemp seals on the cast iron hub joints moist and juicy.  I don't think that do that any more.  I think because of all the ground water leaks into the system that works pretty well in keeping the hemp moist and leak free. Well, mostly leak free.

    I have seen them pump out the sumps in low points in the grid that collects gallons and gallons of ground water seeping in through 100 year old leak repairs.

    So dry gas is good gas.  Dry gas without H2S is even better. 
    All Steamed Up, Inc.
    "Reducing our country's energy consumption, one system at a time"
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Baltimore, MD (USA) and consulting anywhere.
  • TechmanTechman Posts: 2,144Member
    Black pipe

    How rusty will black pipe and fittings get when used outdoors for 1 year, for 20 years? Real good info guys and Bob Harper!
  • jumperjumper Posts: 1,370Member
    galvanized on outside?

    Is that what we're talking about?
  • icesailoricesailor Posts: 7,265Member
    edited May 2014
    Galv. Fittings & Manufactured Gas:

    Where I worked, when I grew up and then started, they had Manufactured Gas in the town. Anything outside was LPG. Any other gas in other areas that had piped gas was probably Natural Gas. The MFGas was made by a process of burning Naptha or Hexane, I don't remember which. I never worked in the gas plant, just the electric generating plant. They used high pressure steam for the heat to get the liquid extremely got, then burned it in a "gas maker" where they burned off the carbon and it was trapped in the "maker". Then, they ignited the carbon and injected air into the furnace which created the gas. It was very low BTU output (350 BTU per Cubic foot?). The company sold gas and electric appliances. A selling point was that ALL gas appliances had to be heavily modified. Like comparing LP to Nat gas. Only the increase was 2X larger than the Nat Gas.

    As far as the Galvanized Fittings and leaking through sand holes, they are cast. I have never seen a galvanized fitting leak through a sand casting pin hole. But I have seen MANY black Malleable fittings leak through sand holes when I tested them. 

    After having many sand hole leaks on Malleable fittings and having a hard time finding them, I started testing to 100# air pressure. Then having the test with my 5# gas gauge. I remembered about the galvanized fittings.

    A local LP gas distributor that does installs, had so many leaks from rust corrosion on black pipe or nipples. Even though they painted all their pipes that are outside. So, they switched to brass pipe, nipples and fittings. They have had problems with bad Chinese pipe and some nipples with leaking Skelp joints.

    They use Galvanized piping on fire sprinkler systems where the piping is outside.

    Its like a saying my grandmother had. "What we hold in memory, is ours forever".  Like bogus code rules. Once there, no matter how stupid, it's there forever.
  • Jean-David BeyerJean-David Beyer Posts: 2,645Member
    The MFGas was made by a process of burning Naptha or Hexane, I don't remember which.

    I suppose it could be done that way. But when I lived in Buffalo, N.Y., from 1942 onward, the gas supplied as manufactured gas was made in the steel mill coking ovens. They need the coke that they made by heating coal in an oxygen deprived furnace. The coke was the desired product, but they got coal tar used in the chemical industry (now mostly replaced by petroleum derivitives) and carbon monoxide, methane, etc. Instead of burning off the gasses, they purified them slightly, pressurized them and distributed it throughout the city. After World War II, natural gas became more plentiful and the steel manufacturing business started its decline in the Buffalo area, and later the whole country. So less manufactured gas was available, and more natural gas was plentiful. In fact, about the same time, coal declined greatly as a fuel for residential heating, replaced mainly by natural gas. By 1950 or so, the city refused to pick up the ashes anymore, so people had no choice but to convert to natural gas. I suppose heating oil was an option, but I cannot remember anyone in the city using it. Perhaps in the suburbs.
  • icesailoricesailor Posts: 7,265Member
    Either or:

    I lived in a place where transportation was the issue. It came by barge. Along with the #6 and diesel oil to start the generators that ran  on Bunker C to run but needed Diesel to start and stop. Gasoline, Kerosene and fuel oil all came by barge. It was nasty Naphtha. I think that Hexane was interchangeable or the same thing. Your description on how it was made. It was explained to me about 40 years ago, but I didn't understand. I guess they used the heat from high pressure steam to boil off the Naphtha and leave the carbon behind. Then. they would fire it off and the result was a gas. It was really hard for them to maintain a consistent BTU level.
  • Tim McElwainTim McElwain Posts: 4,293Member
    You guys sound

    like a bunch of old gas men. That was when men were really men.
  • TechmanTechman Posts: 2,144Member
    Dear Tim

    I am" a bunch of old gas men". LOL
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