On Fri, 13 Mar 2015 10:02:43 -0500, dpb wrote:

On 03/13/2015 8:34 AM, trader_4 wrote:
On Friday, March 13, 2015 at 9:27:11 AM UTC-4, Scott Lurndal wrote:
writes:
On Thursday, March 12, 2015 at 3:13:40 PM UTC-4, wrote:

I have propane gas, and I am allowed to use copper or black iron.
That's all..... (not including the flex pipes behind a range, which are
often brass).

Many places allow galvanized now too.


The main problem with galvy is the propensity for zinc flakes
to clog burner orifices.

Has anyone ever actually seen that happen? I've heard that raised
as one of the theoretically reasons that some places don't allow
galvanized, but it seems very unlikely to me. And if it's so, why
is it that galvanized is now allowed and used in many places for nat
gas, including here?

I've done some looking at various times in the past and have never found
any definitive reasons, either.

The problem w/ the flaking hypothesis (which have heard before too but
never found really documented in a utility handbook/standard) in my mind
is the galvanizing is on the outside of the pipe, they inside is just
black pipe...

I've seen some talk of some reaction w/ trace impurities and the zinc
and all kinds of other speculation but never any clear cut explanation.
The natural gas today is lower sulphur than in the past, the
galvanizing is different, and it has been proven that the actual
incidence of zinc flaking is very low. Also, code now requires a
"condensate drip trap" before all gas appliances, where the flakes and
any other "fall-out" accumulates.

That's my "best read" of the situation. All of my gas is black pipe
except for one little LB that is galvanized because that's all I had,
and all I DIDN"T have in black pipe when I replaced the water heater.
Been 57 months now, and the water heater hasn't gone out yet - - -.