Filter
Top Products
31
36"
12" MIN.
36" MIN.
VENT CAP
VENT PIPE
COMBUSTION
AIR FILTER
BOILER
UNIT
INTAKE
VENT
Model
No.
Appliance
Category
Certified
Venting
Material
Vent Size
(inches)
Min./Max.
Vertical
Venting
Height
(feet)
Combustion
Air Intake
Pipe
Material
Air Inlet
Size
(inches)
Max. Air
Intake
Length
(feet)
122
I
Type B
Equivalent
4
5/25
Galvanized
Steel
PVC
ABS
CPVC
5
40
Subtract 10
ft per
elbow,
Max. two
elbows
162
202
242
5
322 6
Table M: Vertical Venting
Fig. 21: Direct Vent—Vertical Venting (Category I)