Masonry outer chimney and fire safety

[bholler]

Insulation that is squished has very little r value too. If the pipe presses against the side of the raceway there is minimal r value at that point, allowing for heat transfer.

The insulation used for insulating liners is not that easily compressed. This has all been proven many many times with testing with an insulated liner you can have zero clearance from the liner to the minimum 4" masonry and zeto clearance from th

 

[Squisher]

Insulated stainless liner in a masonry chimney with or without a clay liner is far greater protection than a uninsulated stainless liner in a masonry chimney with the clay liner intact. Period.

As others have been repeatedly saying.