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LENNOX HEARTH PRODUCTS • MERIT
VENT TERMINATION
CLEARANCES
Multiple Terminations
These appliances may vent adjacent to and at
the same level with any other gas appliances
(including direct vent appliances), provided
there is at least 2 ft (0.6 m) between the proxi-
mal edges of the vent caps. These appliances
may be vented adjacent to a chimney vent
servicing a solid fuel fireplace, provided the
B-vent cap is at least 2 ft (0.6 m) away from the
nearest point of the chimney opening.
Gas Vent Rule
Gas vent caps are not permitted within 8 ft (2.4
m) of a vertical wall or similar obstruction. Gas
vent caps that are located 8 ft or more from a
portion of a building that extends at an angle
greater than 45° upward from the horizontal
may terminate in accordance with Figure 4,
provided that any discharge opening on
the cap is NEVER LESS THAN 2 ft (0.6 m)
horizontally from the roof surface (National
Fuel Gas Code ANSI Z223.1 (NFPA 54) "Gas
Vent Termination" section) (CAN/CGA B149.1).
6
SERIES B-VENT GAS FIREPLACES • MODELS MLBV-35, MLBV-40 • INSTALLATION INSTRUCTIONS
®
Gas Vent Rule
Roof Pitch is X/12
Minimum Height from Roof to
Lowest discharge Opening
1" (25 mm)
Minimum
Figure 4
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Termination Heights for Vents
Above flat Or Sloped Roofs
Ref. NfPA 54 / ANSI z223.1
Roof Pitch
Flat to 6/12
X
6/12 to 7/12
12
7/12 to 8/12
8/12 to 9/12
9/12 to 10/12
10/12 to 11/12
11/12 to 12/12
12/12 to 14/12
14/12 to 16/12
16/12 to 18/12
18/12 to 20/12
20/12 to 21/12
Table 5
* feet
* Meters
1.0
0.3
1.25
0.38
1.5
0.46
2.0
0.61
2.5
0.76
3.25
0.99
4.0
1.22
5.0
1.52
6.0
1.83
7.0
2.13
7.5
2.29
8.0
2.44
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