Round Gas Vent Product Catalog

How Size and Height Affect
Stove Performance
• The amount of heat the vent gases lose as they ow determines
how much condensation will occur and how strong the draft
will be. To control the heat loses, proper selection of venting
materials is of vital importance.
• Double-wall Type B Gas Vent, with an aluminum inner wall and
a galvanized steel outer wall, has proven to be the ideal choice in
venting materials.
• A Type B Gas Vent Sizing Handbook is available to assist you
with the proper installation. View online at www.duravent.com,
under catalogs and instructions.
Vent Termination Chart
Using listed Type B Gas Vent caps may terminate in accordance with
this table.
Minimum Height
Roof Pitch Feet Meters
Flat to 7/12 1 0.30
Over 7/12 to 8/12 1.5 0.46
Over 8/12 to 9/12 2 0.61
Over 9/12 to 10/12 2.5 0.76
Over 10/12 to 11/12 3.25 0.99
Over 11/12 to 12/12 4 1.22
Over 12/12 to 14/12 5 1.52
Over 14/12 to 16/12 6 1.83
Over 16/12 to 18/12 7 2.13
Over 18/12 to 20/12 7.5 2.29
Over 20/12 to 21/12 8 2.44
Gas Vent Specification Chart
Item Clearances
Maximum
Height
Outer Tube Ø Materials
Locking
Device
UL
Listing
ULC
Listing
Type B Vent
Round 3"-8"
1 inch to combustibles 100 feet ⁄" larger than ID
Inner - .012" Aluminum
Outer - .018" Galvanized
DuraLock MH6357 CMH1276
Round 10" to 16"
See note 2
1 inch to combustibles 100 feet 1" larger than ID
Inner - .016" Aluminum
Outer - .021" Galvanized
TwistLock
Screws
MH6357 CMH1276
Round 18" to 30"
1 inch to combustibles 100 feet
2" larger than ID
See note 5
Inner - .020" Aluminum
Outer - .021" Galvanized
Screws MH6357 CMH1276
Oval Type B Vent
4" and 5"
2" x 4" & 2" x 6" stud wall
and 1 inch to combustibles
See Note 3
2 ⁄" x 7 ⁄"
3 ⁄" x 10 ⁄"
Inner - .012" Aluminum
Outer - .018" Galvanized
Button
Lock
MH6357 CMH1276
Oval Type B Vent
6"
2" x 6" stud wall and 1 inch
to combustibles
See Note 3 3 ⁄" x 12"
Inner - .012" Aluminum
Outer - .018" Galvanized
Button
Lock
MH6357 CMH1276
Type B Vent 3" to 6"
Round Liner
0"/Masonry 50 feet ⁄" larger than ID
Inner - .012" Aluminum
Outer - .018" Galvanized
DuraLock
MH14420
MH6357
CMH1407
DuraFlex AL Gas
Relining 3" to 6"
0"/Masonry 50 feet ⁄" larger than ID .010" Aluminum Flex
Screws
DuraLock
MH14420 --
DuraConnect
3" to 6"
1 inch to combustibles See Note 4 ⁄" larger than ID
.010" Aluminum Flex
.018" Galvalume
DuraLock MH14089 --
DuraConnect II
3" to 6"
1 inch to combustibles See Note 4 ⁄" larger than ID
.010" Aluminum Flex
.018" Galvalume
DuraLock MH14089 --
NOTES
1. Clearance to combustibles is
the air space between vent and
combustibles.
2. Maximum height varies with
equipment over 50’, for taller
applications refer to SDV sizing
handbook (L202). 14"-16" Pipe
require screws.
3. When oval is used on wall
furnaces, minimum height required
from bottom of furnace to cap is 12’,
minimum 16” stud space.
4. Limited by sizing tables.
5. 18” pipe OD is one inch larger
than ID and 20” - 30” OD is 2” greater
than ID.
Type B Gas Vent | Round Gas Vent
DuraVent | www.duravent.com
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