On 2005-11-01, Wayne Whitney wrote:

"Wayne Whitney" wrote:

Design #2: Unpressurized flow through 1.5" copper pipe sleeved in a
2" copper pipe. The space between the pipes is pressurized.

But I'm hoping he will allow design #2 since the positive
pressurization of the potable water should mean any leaks in the
single wall won't contaminate the potable water.

Hmm, thinking about this some more, if there is a small leak in the
single wall, and water is being drawn through the outer pressurized
region, could this suck water in from the unpressurized drain area? A
sort of Venturi effect? Or is the 35 psi (minimum) of domestic water
pressure avoid this?

Cheers, Wayne