33
At least 36 in.
18 in. maximum
Vertical separation
between combustion
air and vent
8 3/4 in. (222mm)for 3 in. (76mm)kit
6 3/4 in. (172mm)for 2 in. (51mm) kit
Roof Te rmination (Preferred)
Abandoned masonry
used as raceway
(per code)
At least
36 in.
A
Maintain 12
 in.
min. clearance above
highest anticipated
snow level, maximum of
24 in. above roof
Concentric Vent and Combustion Air
Roof Termination (preferred)
1
 in.
 
(25mm) 
maximum (typ) from wall to inlet
12
 in. (305mm) 
minimum from
overhang or roof
Maintain 12
 in.
min. clearance above
highest anticipated
snow level or grade
whichever is greater
A
A
t le
a
st
3
6
 in
.
Concentric Vent
and Combustion - Air
Side Te rmination
A
At least 36 in.
Side wall termination
of less than 12
 in. (305mm) 
above highest snow level
12
 in.
 min from
overhang or roof
12
 in.
 
(305mm) 
separation between
 bottom ofcombustion air and
bottom of vent (typ)
Maintain 12
 in.
min. clearance above
highest anticipated
snow level or grade
whichever is greater (typ)
A
At least
 36
 in
.
 A
Maintain 12 in. (305mm)min.
clearance above
highest anticipated
snow level
Maximum of 24 in.(614mm)
above roof
90°
Note: "A" denotes 0 to < 2 in.
 Between the first 2 vents
 Third vent must be > 36 in. away
 (typ)
(914mm)
(305mm)
(914mm)
(305mm)
(305mm)
(914mm)
(914mm)
(457mm)
(51mm)
(914mm)
A05090
Fig. 36 -- Combustion Air and Vent Termination for Direct Vent (2--pipe) System
Abandoned masonry
used as raceway
(per code)
12 in. (305 mm) min. from
overhang or roof
Maintain 12 in. (305mm)
minimum clearance
above highest anticipated
snow level or grade
whichever is greater.
Side wall termination
with 2 elbows (preferred)
12 in. min. (305 mm)from
overhang or roof
Maintain 12 in. (305mm)
minimum clearance
above highest anticipated
snow level or grade
whichever is greater
6 in. (152mm) minimum clearance
between wall and end of vent pipe.
10 in. (254mm) maximum pipe length
Sidewall Te r mi n at io n
with Straight Pipe (preferred)
Roof Termination (Preferred)
Vent
Maintain 12 in .
minimum clearance
above highest anticipated
 snow level maximum of
24 in. (610mm) above roof.
90°
(305mm)
A05091
Fig. 37 -- Vent Pipe Termination for Ventilated Combustion Air System
58MVC