12
A
. ............. 42
B
. ....... 38 1/2
C
. ............. 22
D
. ............. 42
Figure 3. Framing Dimensions
Framing should be
constructed of 2 X 4
lumber or heavier.
Shows center of 12 x 12 vent
framing hole for top and rear
venting. The center of the hole is
one inch (25.4mm) above the
center of the horizontal vent pipe.