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VERTICAL THROUGH-THE-ROOF VENTING FOR NG AND LPG
B - 1
The maximum vertical run of vent pipe is 36 ft. from the top of the fireplace. The fireplace will support a run of a maximum
of 36 ft. Maintain 1" air space clearances on all sides of vents (2" above horizontal vents).
IMPORTANT: REFER TO DRAWING ON PAGE 10 & 11 WHILE FOLLOWING THESE INSTRUCTIONS.
Place the fireplace in its desired location. Drop a plumb bob from the ceiling to the center position of the fireplace flue exit.
Mark the location where the vent will penetrate the ceiling. Drill a small hole at this point. Next, drop a plumb bob from the
roof to the hole previously drilled in the ceiling. Mark and drill the spot where the vent will penetrate the roof. Determine if
ceiling joists, roof rafters or other framing will obstruct the venting system. You may need to relocate the fireplace or need
to offset, to avoid cutting load bearing members.
Cut and frame a 10-3/4" x 10-3/4" opening in the ceiling centered on the hole drilled in No. 1.
To determine the length of the vent pipe required, measure the distance from the fireplace flue outlet to the ceiling, the
ceiling thickness, and the vertical rise in the attic or second story and allow sufficient vent height above roofline. For two
story installations, fire stops are required at each floor level. If an offset is needed in the attic, additional pipe and elbows
will be required.
Assemble the desired lengths of vent pipe and elbows to reach from the fireplace flue outlet. Ensure that all pipe and el-
bow connections are in there fully twist-lock position and are leak-proof. Maintain 1" airspace clearances to combustibles
(2" above horizontal runs). Be sure 1000º silicate sealant (Millpak #65-06-00909) is used on the inner pipe joints of all
pipe sections (DuraVent Only).
If an offset is necessary, it is important to support the vent pipe every 3 ft. to avoid excessive stress on the elbows and
possible separation. Wall straps (#45-01-00231) are available for this purpose.
Whenever possible, use 45º elbows instead of 90º elbows. The 45º elbow offers less restriction to the flow of flue gases
and intake air. If a 90º elbow is necessary there must be a minimum of a one-foot pipe section rise after the 90º elbow to
the vent cap or to the next offset. A maximum of three (3) 90ºelbows are allowed per installation.
o
o
Each 90º elbow, after the first 90
elbow, reduces the maximum horizontal distance by 3'. Each 45
elbow, after the first
o
equivalent 90
elbow, reduces the maximum horizontal distance by 1-1/2'.
Cut a 12" x 12" opening in the roof, centered in the small drilled hole placed in the roof in No. 1. The opening
should be a sufficient size to meet all clearance requirements. Continue to assemble lengths of pipe and el-
bows necessary to reach up through the roofline. Galvanized pipe and elbows may be utilized in the attic, as
well as above the roofline. The galvanized finish is desirable above the roofline due to its higher corrosive re-
sistance.
Slip the flashing over the pipe sections protruding through the roof. Secure the base of the flashing to the roof
with roofing nails and seal flashing to roof. Ensure the roofing material overlaps the top edge of the flashing.
Verify you have at least the minimum clearance to combustibles at the roofline.
Continue to add pipe sections until the pipe and the vent cap meet the minimum building code requirements, as outlined in
No. 8 on the following page.
For multi-story vertical installation, a ceiling fire stop is required at the second floor and any subsequent floors. The open-
ing should be framed to 12" x 12" inside dimensions as described in step No. 5.
Any occupied areas above the first floor, including closets and storage spaces, which the vertical vent passes through,
must be enclosed. The enclosure may be framed and sheet rocked with standard construction materials, however, be
sure to maintain minimum allowable clearances between the outside of the vent pipe and the combustible surfaces of the
enclosure.
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