On Friday, January 3, 2014 6:21:03 PM UTC-5, Gordon Shumway wrote:
On Fri, 03 Jan 2014 16:11:35 -0500, Stormin Mormon

wrote:



Tonight in NYS supposed to be 0F, and wind

chill -10 or so. Which number is the one

which concerns water pipes freezing?



I know the pipes won't get below the actual

temp, but are they more likely to freeze,

with wind?



Wind chill is the effect the combination of cold air and wind has on

exposed flesh relative to only cold air. "Wind chill" has absolutely

no effect on inanimate objects. The wind on an inanimate object will

cool an inanimate object to the ambient temperature quicker than no

wind.


Which of course means that wind chill does have an effect on inanimate
objects, in some cases. If you take an inanimate object like a brick
that's at 70F and put it outside where it's exposed when the wind chill
is 0F it's going to cool off faster than if you put it outside when
the wind chill is 15F, even if the actual temperature in both cases is 20F. Once it's reached 20F, then it will have no further effect of any significance.

In the case of freezing pipes, I would say in many cases wind chill does matter,
because any place that is drafty, or even an exterior wall, is going to
be effected by the wind. The pipe in the wall could be colder on a night
with a lower wind chill, even though the actual outside temp is the same.


It is impossible to get an inanimate object colder than ambient

temperature by using wind that is also ambient temperature.



Now, don't ever ask that question again or I'll turn this car

around...