On Jan 27, 8:41*am, PeterD wrote:
On Tue, 26 Jan 2010 20:07:27 -0500, "Stormin Mormon"

wrote:
I'm also curious for the cite. Where I am, (NY State, USA)
we often have gas lines exposed outside buildings.

Exposed, yes, burried no. Frost heaving can fracture the line if not
properly installed. Frost can move the ground 2 to 4 inches in some
cases, but not a consistant move, someplaces it moves less than an
inch, other places much more. Frost is nasty that way!

My family is using minimum buried lines from New Hampshire out to
Southern California and has been for many years. Not one of my five
sisters not my brother has had a line broken by frost damage. My
church operates summer camps from the mountains of North West Maryland
to the sea coast of the Carolinas. None of those underground propane
lines has ever had frost damage. No that is not a complete geographic
sample of the US but I have not heard of buried gas lines being frost
damaged. I don't see the problem.

--
Tom Horne