17 of 23
9.
INSTALLATIONS WITH THROUGH THE ROOF VERTICAL
TERMINATION
•
Check the roof pitch to determine which roof flashing will be needed
- see vent accessories section 2.4.
•
The distance from the roof to the lowest terminal discharge opening
(“H” in figure 25) depends on the roof pitch and must be in
accordance with the Dura-vent instructions supplied with the
termination unit.
Note: The venting system for these appliances is considered to be a
Special Venting System. The rule in the Installation Code requiring
a minimum vent height of 2ft above any portion of a building within
10ft does not therefore apply.
•
The minimum clearances to combustible materials all round the vent
pipes must be in accordance with the dimensions shown in section 4
of this manual.
•
Drop a plumb from the ceiling to the center of the appliance vent
opening. Mark the position on the ceiling. Drill a small hole at the
marked position.
•
Determine the position where the vent will pass through the roof. If
directly above the position where it penetrates the ceiling, drop a
plumb from the roof to the small hole in the ceiling and mark the
roof at this spot.
If rafters or other obstructions will prevent a vertical exit or if clear
attic space is desired, the roof outlet can be offset using 45º elbows -
see fig. 25.
Drill a small hole at the marked position.
•
A ceiling firestop must be installed
at the second floor
and higher
floors.
A ceiling support should be used below the flat ceiling.
To install the firestop & support cut and frame a 10” (254mm)
square hole centered on the small hole previously
drilled - see fig. 26.
•
Fit vent accessory elbows and pipe lengths as required
up through ceiling support boxes and firestops.
If installation includes offset, support the offsetting
pipes every 3 feet (1m) with wall straps (fig. 25).
•
Cut a hole in the roof centered on the small hole. The
hole must allow for the minimum clearances to
combustible materials - see section 4.
•
Fit pipe lengths through the roof. Fit roof flashing
securing it with roofing nails.
•
Fit storm collar and termination cap.
Fig 26 Firestop hole
Fig 25 Through the roof installation
