propane gas; black iron & galvanized pipe; brass ball valves; dielectric couplings

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by greyhound1, Jul 28, 2010.

  1. greyhound1

    greyhound1 New Member

    Jul 9, 2009
    I hope that this is the right section for this. As a 49 and closing in on 50 year old I know the risk in knowing just enough about a topic to get you into trouble. I live in southeastern PA and am having a propane gas installation. Black iron pipe will be installed in my basement for a dryer, stove and possible future house heater and water heater. We have oil heat now. This question relates to the inside work only. A 16" main consisting of 3/4" galvanized pipe will enter through my masonry block. Only black iron pipe will be used on the inside (1/2" legs to the stove and dryer). Brass ball valves will be used at various points along the pipe (at main and at each present appliance and for future applications, as stated above)

    My questions are:

    1. Can galvanized pipe sit against masonry block (later to connect to the outside regulator) and be exposed to outside elements without or should a sleeve be put through the insertion hole "for protection"? if a sleeve is required, should it be plastic or can it be some other material? (Someone mentioned a copper sleeve but my information tells me that the copper would react with the galvanized and corrode it);

    2. Can galvanized be joined with black iron without causing a galvanic reaction (my thoughts are that they are both steel and not dissimilar metals)? Also, should dielectric couplings be used between the galvanized and black iron? I've read many opinions that galvanized should never be used with propane because of the possibility of flaking zinc damaging the appliances. Is this still an issue?;

    3. Should dielectric couplings be used between the brass valve and black iron? Is it overkill to use these couplings at both ends of each valve? Is it beneficial? Is there a downside? I'm thinking that I would like to do this for my peace of mind;

    4. What material should the fasteners, screws, fastening straps, bands and brackets be against the black iron (carbon steel? galvanized? Any suggestions?)

    5. Is it common to have a drip tube at the dryer (I've mostly seen flex tubing directly at the bottom of the black iron and no drip tube).

    6. Should a dielectric coupling be in between the black iron and flex tubing?

    Any other Southeastern Pennsylvanians know whether this hookup is proper (i.e. code)? I intend to ask these questions to the local building inspector (eventually, when he returns my call!)

    Thank you for all of your assistance.
  2. nhmaster3015

    nhmaster3015 Master Plumber

    Jul 30, 2008
    The granite state
    there shouldn't be any galvanized piping or fittings at all.
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  4. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona
    1. Here, and most places, gas pipe exposed to the weather SHOULD be galvanized, or can be black if it is painted. It you want to pay the extra cost for galvanized, then the entire system can be galvanized pipe. NO sleeving is necessary.
    2. Black and galvanized are mixed all the time. There is no conflict between them.
    3. It would be ridiculous to use a dielectric union at a gas valve and assinine to use them on both sides. Brass valves are often used AS dielectric devices between copper and steel piping.
    4. ANY fasteners that work.
    5. Drip legs are optional, unless the gas composition is such that they are required at all drops.
    6. NO!.
    7. IF they are required anywhere, the only location is where a steel gas line goes into the ground and connects to an underground system.
  5. jimbo

    jimbo Plumber

    Aug 31, 2004
    San Diego, CA
    hj pretty much covered it.

    There was a time where at least in certain areas, galvanized was not used for gas, on the theory that some coating could flake off and clog things. I think that either the galvanized process is different or the theory was just debunked in general, but around here for sure there has been no prohibition in my memory.

    Dielectric couplings are used in a system where a conductive electolyte fluid completes the path for electrons to flow from one material to another, and the molecular structure of the two different metals caused one to give up electrons ( corrode ) and the other metal, the one higher on the nobility scale, to be protected.
    This is totally irrelevant in a GAS system.
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