Astria.US.com
126730-01C
15
Figure 16 - Horizontal Termination Using Two 90° Elbows
Figure 17 - Offset with Wall Strap and 45° Elbows
VENTING INSTALLATION
Continued
Venting with Two 90° Elbows
Vertical (V)
Horizontal (H
1
) +
Horizontal (H
2
)
6' min.
8' max.
7' min.
10' max.
8' min.
15' max.
20' max.
20' max.
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.
2. Set fireplace in desired location. Drop a plumb line down from
ceiling to position 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 inside of roof to locating hole in ceiling.
Mark center point where vent will penetrate roof. Drill a small
locating hole at this point.
45° Elbow
Wall Strap
Roof Flashing
Ceiling Firestop
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 14).
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 sup-
port 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 8 on
page 11.
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.
Vent Termination Chart
Minimum Height
Roof Pitch
Feet Min.
Flat to 6/12
1
6/12 to 7/12
1.25
Over 7/12 to 8/12
1.5
Over 8/12 to 9/12
2
Over 9/12 to 10/12
2.5
Over 10/12 to 11/12
3.25
Over 11/12 to 12/12
4
Over 12/12 to 14/12
5
Over 14/12 to 16/12
6
Over 16/12 to 18/12
7
Over 18/12 to 20/12
7.5
Over 20/12 to 21/12
8.0
