Replies

1. 
   IronHelix | Apr 08, 2003 04:35am | #1

   Code or no code??...I think the real problem lies in the fact that as the galvanized pipe reacts with the compounds in NG/LPG  the resulting flakes have a clogging effect on gas valves and pilot light orfices.

   Locally all gas services are piped in  black pipe or stainless flex (more recently).   If you can handle the $$ the SS is really fine and far less labor intensive.  Less labor balances out the final bill.

   ..............................Iron Helix

1. 
   DaveRicheson | Apr 08, 2003 11:09am | #4

   I think you are right. NG is mostly methane gas with a few other combustable gaes mixed with it by mother nature. Methane CH4 is slightly acidic because of the molecular structure and a  thing called dipole moments. in the presents of a little water it forms methanol, which is also sligthly acidic. Zinc in the galvanized coating of pipe is very reactive to even mild acids.  the reation product is, I think, zinc oxide, whichwhich is a fine white powder than can migrate through the piping to the gas valves.

   If you have a galvanized fitting or nail laying around, drop it in a glass of vinegar, a weak organic acid. The galvanized iten will start a real slow fizz. That is the zinc reacting with the acid. While vinegar is a much stronger acid than methane or methanol, the process will still occures. Most any alcohol is slightly acidic right up to the molecular weight were they become glycerins and then waxes.

   I would not mix galvanized pipe with NG for this very reason.

   Dave

1. 
   JohnSprung | Apr 09, 2003 01:32am | #5

   It depends on the local gas supply.  Out here, we have black and galv. mixed all over.  In my parents' house, most of the gas stuff is galv, OK after 30 years.  Mine is black pipe with some galv ells and stuff, again OK after 77 years.  BIL has a long run to the pool heater, galv underground, about 35 years old.  Rust from the exterior makes it something to keep an eye on, but no apparant problem from the gas inside.

   -- J.S.

2. 
   rjw | Apr 30, 2003 04:30am | #9

   Most any alcohol is slightly acidic right up to the molecular weight were they become glycerins and then waxes.

   Good ice breaker for my next cocktail party {G}_______________________

   10 .... I have laid the foundation like an expert builder. Now others are building on it. But whoever is building on this foundation must be very careful.

   11 For no one can lay any other foundation than the one we already have--Jesus Christ.

   1 Corinthians 3:10-11

2. 
   wallyo | Apr 08, 2003 05:52am | #2

   In Taunton Press how to plumb a house the author uses Black pipe with gal fitting If it is code or not I don't know.  His reasonning is that the galanizing of the fittings stops any pin hole leaks.  Just thought to pass it on. I think it is weird my self.

1. 
   Wet_Head | Apr 26, 2003 03:40am | #6

   Sounds like Peter Hemp!

   That is a scary way to do things.  

   You are right.  That is weird.

3. 
   Clay | Apr 08, 2003 07:26am | #3

   You must not use the galvanized, locally here we are allowed to use soft copper with compression fittings, or black iron pipe.  Stainless or copper flex is used only at appliance connections.

4. 
   Graybeard | Apr 26, 2003 05:37am | #7

    Galvanized pipe is rejected black pipe, the galvanizing process stops corrosion when used for water but it cannot handle high pressure. The acid affecting the zinc is correct and normal gas pressure is low but I don't believe any code will allow galvanized pipe or fittings for natural gas or propane. OSHA won't let you use galvanized for compressed air, so anyone thinking about plumbing their shop for compressed, DON'T use Dad's or Grandpap's old collection of pipe & fittings. Safety seems to be the first thing we forget about!

1. 
   Wet_Head | Apr 29, 2003 08:22am | #8

   Hey... I never knew all that.  Can you point me to a place I can document what you just said?  There are times a printout of that info would be very useful.  Thanks.

   And how did you come to know this?  Sounds like a good story is hiding here waiting to be told.

   Ever rip off a plumber?  Here is your chance.  Buy these $80+ Tub & Shower faucets for a measley 20 bucks plus shipping.  Click HERE to rip him off!