E. Vent Diagrams
To replace the first starter elbow with two 45° elbows, refer to Figure 7.4. All other 90° elbows can be replaced with two 45° elbows.
General Rules:
•SUBTRACT 3 ft. from the total H measurement for each 90° elbow installed horizontally.
•SUBTRACT
•A maximum of three 90° elbows (or six 45° elbows) may be used in any vent configuration.
NOTICE: DO NOT install elbows horizontally.
•Elbows may be placed back to back anywhere in the system as long as the first 90° elbow is a starter elbow except as shown in Figure 7.4.
•When penetrating a combustible wall, a wall shield firestop must be installed.
•When penetrating a combustible ceiling, a ceiling firestop must be installed.
•Horizontal runs of vent do not require vertical rise; horizontal runs may be level.
1. Top Vent - Horizontal Termination
One Elbow
V1
H1
V1 Min. | V1 Max. | H1 Max. |
3 ft (.91 m) | - | 1.5 ft (.46 m) |
4 ft (1.22 m) | - | 6 ft (1.83 m) |
|
|
|
5 ft (1.52) | - | 11 ft (3.35 m) |
6 ft (1.83 m) | - | 13 ft (3.96 m) |
|
|
|
7 ft (2.13 m) | - | 15 ft (4.57 m) |
10 ft (3.05 m) | 25 ft (7.62 m) | 20 ft (6.10 m) |
Figure 7.3
28 | Heat & Glo • LUX60 • |
