On Tue, 7 Jan 2014 05:38:06 -0800 (PST), "
wrote:

You don't need the windspeed at the pipe. The windspeed at the
pipe could be very low. The pipe could be out of the main
wind. But a 35mph 15F wind blowing into a drafty crawlspace
through a couple of openings could still drop the temp of the
rest of the crawlspace low enough to freeze the pipes, even
if the air around the pipes is barely moving. Your house gets
heated/cooled from a relatively modest amount of air blowing out
of registers.

Your above statement is absolutely correct. The wind chill in your
above example is unknown and irrelevant because the temp is 32° F or
below. Because of the air temperature the pipes could freeze. The
fact that the wind is blowing will only decrease the time required.
That's all I've been saying.

Snip

Here, from the Weather Channel:
http://www.weather.com/activities/ho...e_prevent.html


"Pipes in attics, crawl spaces and outside walls are all vulnerable to freezing, especially if there are cracks or openings that allow cold, outside air to flow across the pipes. Research at the University of Illinois has shown that €œwind chill,€? the cooling effect of air and wind that causes the human body to lose heat, can play a major role in accelerating ice blockage, and thus bursting, in water pipes."


From City of Rochester:

http://www.rochesternh.net/public_Do...ER%20PIPES.pdf
"Pipes inside or outside walls, or in an enclosed area can freeze,
especially when the wind-chill factor is well below zero and heat is
not circulating in those areas."

Because you found it on the Internet doesn't make it true. Hell, the
one example I gave earlier you picked apart.