Venting Installation
Continued
Existing
Ceiling
Frame
Firestop 
Spacer
Screws or 
Staples (Min. of 8)
Figure 14 - Firestop Spacer with Living
Space Above Ceiling
| Screws or Staples |
Firestop | (Min. of 8) |
Spacer | Existing |
| |
| Ceiling |
| Frame |
combinations of 12", 18", 36" and 48" length of double wall pipe (see offset chart and Figure 18).
Maximum length of pipe between supports
2" (5.1cm) Minimum
Angled Firestop
Ceiling
Support
Straps
Return 
Elbow
Figure 15 - Firestop Spacer with Attic
Space Above Ceiling
and 12" length of pipe. A chimney support is required every 30 feet above fireplace after a straight chimney run or above a return elbow after a straight chimney run (see Figure 16). This support is designed to relieve the extra weight load on firebox and elbows when high
chimneys are installed.
Elbow Offset Installation
| |
Support |
|
30 FT. Required | 30 FT. |
(9.14m) | (9.14m) |
Return
Elbow
Figure 16 - Elbow Offset
Chimney weight above offset rests on return elbow. Straps must be securely nailed to rafters or joists (see Figure 17).
To achieve desired offset, you may install
Figure 17 - Chimney Supports
Screws
B
A
OFFSET | RISE | CHIMNEY LENGTH | |||
A | B | 48" | 36" | 18" | 12" |
4 3/8" | 16 3/8" |
|
|
|
|
9 1/2" | 25 1/4" |
|
|
| 1 |
12 1/2" | 30 3/8" |
|
| 1 |
|
14 3/8" | 34" |
|
|
| 2 |
17 5/8" | 39 1/4" |
|
| 1 | 1 |
21 1/2" | 46" |
| 1 |
|
|
22 3/4" | 48 1/8" |
|
| 1 | 2 |
26 3/8" | 54 7/8" | 1 |
|
|
|
26 3/8" | 60" |
| 1 | 1 |
|
31 3/4" | 63 3/4" | 1 |
|
| 1 |
34 3/4" | 69" | 1 |
| 1 |
|
38 5/8" | 75 5/8" |
| 2 |
|
|
39 7/8" | 77 7/8" | 1 |
| 1 | 1 |
43 3/4" | 84 1/2" | 1 | 1 |
|
|
46 3/4" | 87 3/4" |
| 2 | 1 |
|
48 7/8" | 93 3/8" | 2 |
|
|
|
Figure 18 - Rise and Offset
8 | www.desatech.com | 55511E |