Astria.us.com
126733-01H
15
Figure 16 - Horizontal Termination Using Two 90° Elbows
Figure 17 - Offset with Wall Strap
and 45° Elbows
VENTING INSTALLATION
Continued
Vertical Termination Installation
NOTE:
Vertical restrictor must be installed in all vertical installations.
1. Determine route your vertical venting will take. If ceiling joists,
roof rafters or other framing will obstruct venting system, consider
an offset
(see
Figure 17
)
to avoid cutting load bearing members.
NOTE:
Pay special attention to these installation instructions for
required clearances (air space) to combustibles when passing
through ceilings, walls, roofs, enclosures, attic rafters, etc. Do not
pack air spaces with insulation. Also note maximum vertical rise
of venting system and any maximum horizontal offset limitations.
45° Elbow
Wall
Strap
Roof
Flashing
Ceiling Firestop
2. Assemble desired lengths of pipe and elbows necessary to reach
from fireplace flue up through firestop. Be sure all pipe and elbow
connections are fully twist-locked
(see
Figure 9, Page 13
)
.
3. Cut a hole in the roof using locating hole as a center point. (Cover
any exposed open vent pipes before cutting hole in roof.) The 11-
1/2" x 11-1/2" hole must be measured on the horizontal; actual
length may be larger depending on pitch of roof. There must be a 1"
clearance from vent pipe to combustible materials. Frame opening
as shown in
Figure 10, Page 13
.
4. Connect a section of pipe and extend up through hole.
NOTE:
If an offset is needed to avoid obstructions, you must support
vent pipe every 3 feet. Use wall straps for this purpose
(see
Figure
17
).
Whenever possible, use 45° elbows instead of 90° elbows.
The 45° elbow offers less restriction to the flow of flue gases.
5. Place flashing over pipe section(s) extending through roof. Secure
base of flashing to roof and framing with roofing nails. Be sure roofing
material overlaps top edge of flashing as shown in
Figure 17
. There
must be a 1" clearance from vent pipe to combustible materials.
6. Continue to add pipe sections until height of vent cap meets the
minimum building code requirements described in
Figure 17a
.
NOTE:
You must increase vent height for steep roof pitches. Nearby
trees, adjoining rooflines, steep pitched roofs and other similar
factors may cause poor draft or down-drafting in high winds.
Increasing vent height may solve this problem.
7. Twist-lock vent cap onto last section of vent pipe.
Venting with Two 90° Elbows
Vertical (V)
Horizontal (H
1
+ H
2
)
feet
(meters)
feet
(meters)
6' Min.
(1.829)
8' Max
(2.439)
7' Min.
(2.134) 10' Max
(3.048)
8' Min.
(2.439) 15' Max
(4.572)
20'Max. (6.096) 20' Max
(6.096)
Roof Pitch
Termination Height *
Flat to 6/12
1.0 ft (0.3 m)
6/12 to 7/12
1.25 ft (0.38 m)
7/12 to 8/12
1.5 ft (0.46 m)
8/12 to 9/12
2.0 ft (0.61 m)
9/12 to 10/12
2.5 ft (0.76 m
10/12 to 11/12
3.25 ft (0.99 m)
11/12 to 12/12
4.0 ft (1.22 m)
12/12 to 14/12
5.0 ft (1.52 m)
14/12 to 16/12
6.0 ft (1.83 m)
16/12 to 18/12
7.0 ft (2.13 m)
18/12 to 20/12
7.5 ft (2.29 m)
20/12 to 21/12
8.0 ft (2.44 m)
Figure 17a- Termination Heights for Vents above Flat or Sloped
Roofs (NFPA 54 / ANSI Z223.1)—Gas Vent Rule
12
X
Roof pitch is X/12
2 ft
minimum
2 ft minimum
Lowest
discharge
opening
H*
*H = minimum height from roof to
lowest discharge opening of vent
Horizontal overhang
Vertical
wall
Vent
termination
Storm collar
Concentric
vent pipe
Flashing
1” (26 mm) minimum
clearance to combustibles
2. Set fireplace in desired
location. Drop a plumb line
down from ceiling to posi-
tion of fireplace exit flue.
Mark center point where
vent will penetrate ceiling.
Drill a small locating hole
at this point.
3. Drop a plumb line from in-
side of roof to locating hole
in ceiling. Mark center point
where vent will penetrate
roof. Drill a small locating
hole at this point.
Flat Ceiling Installation
1. Cut an 11-1/2" square hole in ceiling using locating hole as a center
point. Opening should be framed to 11-1/2" x 11-1/2" inside dimen-
sions, as shown in
Figure 10 on Page 13
using framing lumber the
same size as ceiling joists. If area above ceiling is an insulated ceiling
or an attic, nail firestop from top side. This prevents loose insulation
from falling into required clearance space. If area above ceiling is a living
space, install firestop below framed hole. Firestop should be installed
with no less than three nails per side
(see
Figure 15, Page 12
).
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