Initial Installation
QUALIFIED INSTALLERS ONLY
support straps to the roof. Seal the nails holes heads with
7.Slip the flashing over the pipe section protruding through the roof. Secure the base of the flashing to the roof with roofing nails. Use a
8.Continue to add pipe sections until the height of the vent cap meets the minimum code requirements. Refer to Figure 31 and Table 5. Note that for steep roof pitches, the vent height must be increased. In high wind conditions, nearby trees, adjoining roof lines, steep pitched roofs, and other similar factors can result in poor draft, or down drafting. In these cases, increasing the vent height may solve the problem.
9.Slip the storm collar over the pipe, and push it down to the top of the roof flashing as shown in Figure
30.Use the
10.Twist-lock the vent cap.
Figure 31: Height of Vertical Termination;
Reference Table 5.
Table 5: Minimum ‘H’ for Figure 31.
Roof Pitch | Minimum Height | |
|
|
|
| Ft | Meters |
|
|
|
Flat to 7/12 | 1 | 0.3 |
|
|
|
Over 7/12 to 8/12 | 1.5 | 0.46 |
|
|
|
Over 8/12 to 9/12 | 2 | 0.61 |
|
|
|
Over 9/12 to 10/12 | 2.5 | 0.76 |
|
|
|
Over 10/12 to 11/12 | 3.25 | 0.99 |
|
|
|
Over 11/12 to 12/12 | 4 | 1.22 |
|
|
|
Over 12/12 to 14/12 | 5 | 1.52 |
|
|
|
Over 14/12 to 16/12 | 6 | 1.83 |
|
|
|
Over 16/12 to 18/12 | 7 | 2.13 |
|
|
|
Over 18/12 to 20/12 | 7.5 | 2.29 |
|
|
|
Over 20/12 to 21/12 | 8 | 2.44 |
|
|
|
NOTES:
•If an offset is necessary in the attic to avoid obstructions, it is important to support the vent pipe every 3 ft (91 cm), to avoid excessive stress on the elbows, and possible separation. Wall straps are available for this purpose (see Figure 32).
•When ever possible, use 45° degree elbows instead of 90° degree elbows. The 45° degree elbow offers less restriction to the flow of flue gases and intake air.
Figure 32: Use of Wall Straps.
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