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Vertical Through-The Roof Venting
The maximum vertical run of vent pipe is 55 ft. from the top of the fireplace. The fireplace will support a run of a
maximum of 55 ft. The vent system must be supported every 3 feet using Support Straps. Maintain 1" air space
clearances on all sides of vent components that are positioned vertically and 2" above horizontal pipe sections and
components.
THIS FIREPLACE MUST BE INSTALLED BY A QUALIFIED MENDOTA APPROVED SERVICEPERSON.
1. Place the fireplace in its desired location. Drop a plum bob from the ceiling to the 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 plum 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 choose to relocate the fireplace or choose to
offset the vent system to avoid cutting load bearing members.
2. Cut and frame a 9" x 9" opening in the ceiling centered on the hole drilled in Step 1.
3. 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.
4. Assemble the desired lengths of vent pipe and elbows to reach from the fireplace flue outlet. Ensure that all vent pipe and
elbow connections are in their fully twist-lock position and that inner pipe joints are sealed and are leak-proof. Maintain 1"
airspace clearances to combustibles around vertical pipe sections and 2" clearance above horizontal run sections.
5. Cut a 9" x 9" opening in the roof, centered in the small drilled hole placed in the roof in Step 1. The opening should be a
sufficient size to meet all clearance requirements. Continue to assemble lengths of pipe and elbows 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 resistance.
a.
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 are available for this purpose.
b. 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 one pipe section rise between the 90º elbow and the vent
cap. A maximum of three 90ºelbows are allowed per installation.
6. 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.
7. Continue to add pipe sections until the pipe and the vent cap meet
the minimum building code requirements.
For multi-story vertical installation, a ceiling fire stop is required at the
second floor and any subsequent floors. The opening should be
framed to 9" x 9" inside dimensions as described in step No. 5.
Add an attic insulation shield to keep attic insulation materials away
from vent pipe.
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.
8. Height "*H" of top of vent cap can be determined as follows:
9. Complete installation with storm collar and vent cap.
Height "*H" from roof surface to the top of vent cap can be determined
as follows:
Complete installation with storm collar and vent cap.
85-03-01116
ROOF PITCH
FLAT to 6/12
7/12 to 9/12
10/12 to 12/12
13/12 to 16/12
17/12 to 21/12
DXV42 TIMBERFIRE
"H" DIMENSION
FEET
METERS
2
.6
2
.6
4
1.2
6
1.8
8
2.4
Figure 4-13 Roof Pitch versus
Vent Cap Height
Page 59
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