Astria.us.com
901046-00NC
10
VENTING INSTALLATION
Continued
Figure 11 - Elbow Offset
FIRESTOP SPACERS (3600FS-8DM-1)
Firestop spacers are required at each point where chimney penetrates
a floor space. Their purpose is to establish and maintain required
clearance between chimney and combustible materials. When pipe
passes through a framed opening into a living space above, firestop
must be placed onto ceiling from below as shown in Figure 12.
They also provide complete separation from one floor space to an-
other or attic space as required by most codes. When double wall
pipe passes through a framed opening into an attic space, firestop
must be placed into an attic floor as shown in Figure 13.
Figure 12 - Firestop Spacer with Living Space Above Ceiling
Figure 13 - Firestop Spacer with Attic Space Above Ceiling
If area above is a living space, install
firestop below framed hole.
If area above is an attic or insulated
area, install firestop above framed hole.
PENETRATING ROOF
To maintain a 1" clearance to pipe on a roof with a pitch, a rectangular
opening must be cut.
1. Determine center point where pipe will penetrate the roof.
2. Determine center point of the roof. Pitch is the distance the roof drops
over a given span, usually 12". A 6/12 pitch means that the roof drops
6" for each 12" measure horizontally down from roof rafters.
3. Use roof opening chart (Figure 14, page 11) to determine correct
opening length and flashing required.
4. Remove shingles around opening measured. Cut out this section.
5. Add next sections of pipe until end penetrates roof line. Check to
see that proper clearances are maintained. Extend chimney by add-
ing sections of double wall pipe until pipe is minimum of 30" above
highest point of roof cutout. Termination and chimney must extend
a minimum of 36" above highest point where it passes through roof.
B
A
Screws
OFFSET
RISE
CHIMNEY LENGTH
A
B
48" 36" 24" 18" 12"
4
3
/
8
"
16
3
/
8
"
ELBOW SET ONLY
9"
25
3
/
4
"
1
11
7
/
8
"
31"
1
15"
37
3
/
8
"
1
16
3
/
4
"
40
1
/
2
"
1
1
20"
47
1
/
8
"
1
22
5
/
8
"
52
1
/
8
"
1
1
25
1
/
2
"
57
7
/
8
"
1
27
5
/
8
"
62"
1
1
30
3
/
8
"
67
1
/
4
"
1
1
33"
72
5
/
8
"
1
1
35
3
/
4
"
78"
2
37
7
/
8
"
82"
1
1
1
41
1
/
4
"
88
5
/
8
"
1
1
43
3
/
8
"
92
3
/
4
"
2
1
46
5
/
8
"
99
3
/
8
"
2
48
3
/
4
"
103
1
/
2
"
1
1
1
51
1
/
2
"
108
7
/
8
"
2
1
54
1
/
4
"
114
1
/
8
"
2
1
57"
119
1
/
2
"
1
2
59"
123
5
/
8
"
2
1
1
61
3
/
4
"
129"
1
2
1
64
1
/
2
"
134
3
/
8
"
1
2
1
67
1
/
4
"
139
5
/
8
"
4
Figure 13a - Firestop Thimble
Thimble
38FST or
FST30
Firestop
IMPORTANT NOTICE
When penetrating a ceiling into an attic, a firestop thimble
(38FST or FST30) is required to avoid intrusion by insulation
and recommended to negotiate a joist (see Figure 13a).
