On Tuesday, December 15, 2015 at 9:05:57 AM UTC-5, trader_4 wrote:
On Tuesday, December 15, 2015 at 8:47:22 AM UTC-5, KenK wrote:
How cold does that split sleeve-type insulation that you slide over water
lines protect to? 0? 10?

TIA

--
You know it's time to clean the refrigerator
when something closes the door from the inside.

To ~32. Insulation only slows down heat transfer, it doesn't stop it.
If you have no water flow, leave standing water in a pipe with insulation
on it long enough, it will freeze just like it would without insulation.

that is correct for the case the OP asked about where the insulation is wrapped directly around the pipe. If the air around the pipe is under 32, the water will enetually freeze, insulation or not.

BUT...

if this is indoors, a crawl space etc. and instead of wrapping the pipe itself, you instead install insulation as a barrier between the cold outside and the warm inside, so that you can keep the air around the pipe above 32, that can keep the pipe from freezing.

Of course, this won't work at all if you are talking about a pipe that is outside or if there is no heat at all in the house.