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Section 3-2: Installing a Roof Mounted Direct Vent
Termination for 4''/7'' (MVTK-1)
This section applies to installations where the direct vent termination
will be roof mounted.
Section 3-2-1: Venting Layout
Selection of components and details of venting lay out should adhere
to the following guidelines:
• The maximum termination point is 34' above the fireplace (NOTE:
if the maximum termination height is used, the flame pattern may
be affected).
• The Vertical termination must be a minimum 2' higher than where
the termination exits the roofing materials, (asphalt shingles, cedar
shakes, etc). This distance should be measured from the high side of
the roof slope where the flue flashing intersects the roofing materials.
• Termination location must be a minimum 6' from a mechanical air inlet.
• For a more detailed diagram of allowed termination locations, see
Appendix A.
• A maximum of two offsets (each offset is made up of 2-90° bends) may
be made for vertical vent runs. (2 45° bends are equivalent to 1 90°)
• Firestops must be installed as required by National & local codes.
• Ensure all horizontal runs are supported with a minimum of 3
supports per 10' of venting.
• Install all roof flashing and storm collars as shown.
Roof mounted terminations
The following details are some possible configurations for roof mounted
terminations. See below.
MVTK1 Termination
Storm collar
Roof flashing
34' max
Figure 6. Top vent, roof mounted termination with no offset in vent run.
XG0226 - 042220
2' min
Support ring
Support plate
Firestop
MVTK1 Termination
Storm collar
Roof flashing
32' max
(1 elbow)
Obstacle
Figure 6.b Top vent, roof mounted with 1 offset (1 offset= two 90° bends).
MVTK1 Termination
Storm collar
Roof flashing
23' max
(4 elbows)
Obstacle
Figure 6.c Top vent, roof mounted with 2 offsets (1 offset= two 90° bends).
Installation
2' min
Support ring
Support plate
Firestop
2' min
Support straps OR
Support ring and
plates
Firestop
Support ring and
plates
Firestop
Firestop
21
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