At 09:47 AM 11/15/2012 -0800, you wrote:
?
On 11/15/2012 8:55 AM, Alan Muller wrote:
Personally, I have only ever used threaded steel pipe for
gas.
Whatever you use, make sure the AHJ* approves of it AND you feel it's
safe.? Just because it barely meets code doesn't me you HAVE to use
it, pick something even better.? The AHJ will often notice and have
a higher opinion of you.
It's impossible to over-emphasize this point.? The code is what the
inspector says it is.? Many people post opinions on code issues on
the Internet assuming that whatever they were told in their jurisdiction
is universal.? It isn't.? That said, many jurisdictions have
little inspection and enforcement.? Especially in rural areas and on
farms, people are effectively on their own.? Two areas of difference
I know of:? (1)? Using galvanized pipe and fittings for
gas.? It has been found in some cases that the zinc reacts with
compounds in the gas.? Some places will not approve galvanized gas
pipe, and/or fittings.? Others, I think, will. (2) Using thread
sealing tape for gas.? Some tapes have approvals, some don't.?
Some jurisdictions allow use of the approved tapes (color coded), some
will not.
Gas varies in composition.? There was a situation on the East Coast
where a gas utility started using a lot of imported
"LNG."? Their system had lots of connections made with
compressed rubber donuts ("Dresser couplings")? The
different flavor of gas caused the rubber to shrink and there were lots
of leaks....and lots of litigation over responsibility.
Many people think that since threaded fittings now mostly come from China
or Mexico the quality has changed.? I have encountered malleable
fittings with cracks, and with the threads out of line.?
Here (50+ year old house) for a
remodel we used black steel pipe** with stainless flex tube ($20 for a
short piece of that about 5 years ago!).? Note that the flex tube is
rated for exactly ONE use.? If you loosen the fittings, you toss it
in the trash and buy a new one.
I know there is more than one brand of this and the fittings aren't
identical.? But I thought it was only the sealing elements than
can't be reused.?? As noted, the stuff is very expensive.?
There is a failure mode involving pinholes caused by electrical
discharges--lightening strikes.? It needs to be bonded and grounded
per the instructions.
Industrial practice is to paint pipes different colors.? Gas=Yellow,
Sprinkler water=Red, etc.
*AHJ = Authority Having
Jurisdiction.? Depending on where you are, that could be the
building inspector, fire marshal, your boss, your spouse, etc.
** black steel is used so plumbers don't think it's water pipe and unhook
it...like happened to a building a few blocks from here.? Destroyed
the building and killed one plumber, seriously injured another.
--
Jerry Durand, Durand Interstellar, Inc.?
tel: +1 408 356-3886, USA toll free: 1 866 356-3886
Skype:? jerrydurand
