an air cooled StormShield
flue pipe needs to be measured by its INSIDE measurement.
Typically... an air cooled flue system will consist of
an inner and outer pipe(s) with an air space between them. Some
systems may have braces, wire, tabs or smaller openings between the
layer(s) of pipe. The distinguishing factor for this system is
that the spacing channels from the top where the chimney cap would go
all the way to the start of the flue system.
Note: All layers of pipe need to be at the same level
for proper installation. Most pipe can be trimmed or extended to