I have insulated a 'sweaty' pipe to prevent condensation from forming and dripping on to ceiling tiles (hyperlink provides context). I have been advised that the insulation foam should have the slit at the 6PM position.
- What is the reason to orient the slit at 6PM and not 12PM?
The PVC pipe in questions carries cold water from second-story (AC evaporator) to the outside. Because it runs above paneled ceiling on the first floor, the pipe 'sweats' and the condensation drips onto the ceiling tiles (resulting in stains and mold).