If you insulate the pipes from the interior of the living space, the
pipes will be exposed to the cinder block wall of that part of the
foundation. If the air space surrounding the pipes goes below freezing
- guess what happens?

If you insulate the **** around the pipes, you will insure that the
pipes will eventually reach the same temperature as the cinder blocks
that they're in contact with. So you'd have to judge just how cold that
gets. Also - is there any insulation or barrier on the outside of the
blocks?

Thank you. You have a _very_ valid point.