41
Ve
ntin
g
MULTIVENTING OF DIRECT-VENT FURNACES
GENERAL VENTING REQUIREMENTS AND
GUIDELINES
TWO-PIPE VENTING
THROUGH ROOF
TWO-PIPE VENTING
THROUGH WALL
3” (8cm) MIN.
12” (32cm) MAX.
COMBUSTION
AIR INTAKE
2” PVC
8”/20cm
MIN.
SEE DETAIL
“A”
12”/31cm MIN. ABOVE
GRADE OR HIGHEST
ANTICIPATED SNOW LEVEL.
CANADA: MUST CONFORM TO
CSA B149.1-10, SECT. 8.14
A
See
TWO-PIPE VENTING
THROUGH ROOF
TWO-PIPE VENTING
THROUGH WALL
3”/8cm
MAX.
TERMINATIONS
MUST BE GREATER
THAN 8” APART.
COMBUSTION
AIR INTAKE
2” PVC
8”/20cm
MIN.
SEE DETAIL
“A”
12”/31cm MIN. ABOVE
GRADE OR HIGHEST
ANTICIPATED SNOW LEVEL.
CANADA: MUST CONFORM TO
CSA B149.1-10, SECT. 8.14
Figures 27 & 28
:
NOTE: WHEN VENTING MULTIPLE FURNACES IN CLOSE PROXIMITY, EACH FURNACE MUST
BE INDIVIDUALLY VENTED – NO COMMON VENTING IS PERMITTED. See
Figures 27 & 28
for positioning of the
terminations. When more than two furnaces are to be vented, there must be at least 4 feet between the first two fur-
naces and the third and etc.
Figure 27, (Detail A)
below shows the necessary detail for the roof penetration on a stan-
dard direct-vent vertical termination.
MINIMUM 12”/31cm IN
U.S. ABOVE AVERAGE
SNOW ACCUMULATION.
MAXIMUM OF 24”/61cm
ABOVE ROOF.*
6’ (1.8m) MINIMUM
10’ (3m) RECOMMENDED
A
A
SEE
SEE
MINIMUM 12”/31cm
ABOVE GRADE IN U.S.
*
*
12” (31cm) U.S.
CANADA: TERMINATIONS
MUST CONFORM TO
CSA B149.1-10, SECT. 8.14
48” MAX.
(122 cm)
45” MAX.
(114 cm)
36” MAX.
(91 cm)
3” MIN.
(8 cm)
MINIMUM 12”/31cm IN
U.S. ABOVE AVERAGE
SNOW ACCUMULATION.
MAXIMUM OF 24”/61cm
ABOVE ROOF.*
6’ (1.8m) MINIMUM
10’ (3m) RECOMMENDED
A
A
SEE
SEE
MINIMUM 12”/31cm
ABOVE GRADE IN U.S.
*
ST-A1194-18
DETAIL A
ST-A1194-21
ST-A1194-22
DETAIL A
CONCENTRIC VENTING THROUGH ROOF
CONCENTRIC VENTING THROUGH WALL
TWO PIPE VENTING THROUGH ROOF
TWO PIPE VENTING THROUGH WALL
DIRECT VENT VERTICAL TERMINATION DETAIL
*3” (8cm) minimum only if no snow accumulation is anticipated.
*
CANADA: TERMINATION MUST CONFORM TO CSA B149.1-10,
SECT 8.14.
ST-A1194-22
2 FURNACES
➀
Terminations must be greater than 8” apart.
➁
Terminations must be less than 24” apart or greater than
➁
36” apart.
3rd OR MORE FURNACES
Each additional termination must be greater than 48” from
the previous termination.
A
TERMINATIONS MORE THAN
24” ABOVE ROOF PENETRA-
TION REQUIRE ADDITIONAL
SUPPORT.
A
NOTE:
IF 3
Ø
VENTING IS USED,
BOTH PIPES (INTAKE
AND EXHAUST) MUST
BE REDUCED TO 2
Ø
BEFORE PENETRATING
ROOF.
NOTE:
IF 3
Ø
VENTING IS
USED, BOTH
PIPES (INTAKE
AND EX-
HAUST) MUST
BE REDUCED
TO 2
Ø
BEFORE
PENETRATING
ROOF.
FIGURE 27
TWO FURNACE VENTING
FIGURE 28
TWO FURNACE VENTING WITH CONCENTRIC VENTING