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Type B Gas Vent

Type B Gas Vent

DuraVent's innovative system for a lock-tight connection for Type B Gas Vent called DuraLock. See the alignment indicators meet; feel the ends grasp together; hear the snap as the connection firmly locks into place.

DuraVent Type B Gas Vent is designed to meet the rugged demands of the job site. The inner wall is recessed to eliminate damage in handling.

Type B Gas Vent has been engineered to heat up rapidly. It remains hot during the operation of the appliance with minimal condensation in the appliance and vent system. Pipe lengths are available in multiple lengths, 6 to 60 inches, with a full complement of adjustable and rigid fittings.

Type B gas vents are not suitable for use with wood-burning or coal applications, industrial ovens, exhaust ranges and hoods, grease or pollution ducting, or as free-standing exhaust vents for high-temperature applications.

  • Specifications
  • Typical Installation
  • Literature
  • Warranty

Applications
DuraVent's Type B Gas Vent system. Use with natural gas or liquid propane category I and draft hood equipped appliances, and appliances tested and listed to use Type B Gas Vent. Applications include: natural gas fireplaces, gas-fired furnaces, boilers, water heaters, and wall or space heating applications.

Materials and Construction
Round Type B Gas Vent 3" - 8" and oval 4" - 6": Aluminum .012" inner wall, galvanized .018" outer wall. Round Type B Gas Vent 10" - 16": Aluminum .016" inner wall, galvanized .021" outer wall. Round Type B Gas Vent 18" - 3": aluminum .020" inner wall, galvanized .021" outer wall. 3"-16" diameters feature twist-lock fittings, screws required for 14" and larger diameters.

Clearances
1" clearance to combustibles in single and multi-family dwellings.

Diameters
3"- 30" Round Diameter. 4", 5" and 6" Oval.

Listings
UL Listed to UL 441 and UL 1777 (MH6357). ULC Listed to ULC S605 (CMH1276 & CMH1407).

Refer to our Typical Venting Installation drawings to select the appropriate component parts for your installation.

Type B Gas Vent Typical Installations

More Typical Installations:

Type B Gas Vent Typical Installations

Installation Key
1 DuraCap
2 Storm Collar
3 Roof Flashing
4 High-Wind Cap
5 Round Pipe
6 Elbow
7 Tee
8 Tee Cap
9 Increaser Tee
10 Female Flex Adapter
11 Male Adapter
12 Double-Wall Wye
13 Pipe Collar
14 Increaser
15 Draft Hood Connector
16 Square Firestop Support
17 Oval Pipe
18 Oval to Round Adapter
19 Oval Tee
20 Oval Tee Cap
21 Oval Tee Support
22 Oval Firestop Spacer
23 DuraConnect II
24 DuraFlex AL Length
25 DuraFlex Motar Sleeve
26 DuraFlex AL Coupling

How Size and Height Affect Stove Performance

  • The amount of heat the vent gases lose as they flow 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.

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 5/8" 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 1/2" x 7 1/4" 3 1/8" x 10 7/8" 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 1/4" x 12" Inner - .012" Aluminum Outer - .018" Galvanized Button Lock MH6357 CMH1276
Type B Vent 3" to 6" Round Liner" 0"/Masonry 50 feet 5/8" larger than ID Inner - .012" Aluminum Outer - .018" Galvanized DuraLock MH14420 MH6357 CMH1407
DuraFlex AL Gas Relining 3" to 6" 0"/Masonry 50 feet 1/4" larger than ID .010" Aluminum Flex Screws DuraLock MH14420 --
DuraConnect 3" to 6" 1 inch to combustibles See Note 4 1/4" larger than ID .010" Aluminum Flex .018" Galvalume DuraLock MH14089 --
DuraConnect II 3" to 6" 1 inch to combustibles See Note 4 1/4" larger than ID .010" Aluminum Flex .018" Galvalume DuraLock MH14089 --

Note:

  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.

M&G DuraVent Limited Lifetime Warranty

M&G DuraVent, Inc. (“DuraVent”) provides this limited lifetime warranty for all of its products with the exception of Ventinox® (lifetime), and PolyPro® (ten years). Subject to the limitations set forth below, DuraVent warrants that its products will be free from defects in material or manufacturing, if properly installed, maintained and used. DuraVent products are fully warranted if installed only by a professional installer. This Warranty is transferable from the original homeowner to the buyer of the home. This warranty does not cover normal wear and tear, smoke damage or damage caused by chimney fires, acts of God, or any product that was: (1) purchased other than from an authorized DuraVent dealer, retailer or distributor; (2) modified or altered; (3) improperly serviced, inspected or cleaned; or (4) subject to negligence or any use not in accordance with the installation instructions included with the product as determined by DuraVent. Installation instructions are available online at www.duravent.com under Support/Literature and through our Customer Service Department 800-835-4429 or customerservice@duravent.com. This limited lifetime warranty applies only to parts manufactured by DuraVent.

DuraVent provides the following warranties for its products: One Hundred Percent (100%) MSRP 15 years from the date of purchase, and Fifty Percent (50%) thereafter, except for the following limitations on: all Termination Caps and DuraBlack® are warranted at One Hundred Percent (100%) for five years.

All warranty obligations of DuraVent shall be limited to repair or replacement of the defective product pursuant to the terms and conditions applicable to each product line. These remedies shall constitute DuraVent’s sole obligation and sole remedy under this warranty. This warranty provides no cash surrender value. The terms and conditions of this warranty may not be modified, altered or waived by any action, inaction or representation, whether oral or in writing, except upon the express, written authority of an executive officer of DuraVent.

Corn, bio-fuels, driftwood or other wood containing salt, preservative-treated lumber, plastic and household trash or garbage, or wood pellets containing such materials must not be burned in the appliance or fireplace. In case of a chimney fire, the chimney must be inspected and approved by a certified Chimney Sweep before reuse. After each annual inspection, maintenance, and cleaning, the certified Chimney Sweep must fill out and date the appropriate section of the warranty card provided with the chimney liner.

LIMITATIONS ON INTERNET SALES: Notwithstanding any other terms or conditions of this Limited Lifetime Warranty, DuraVent provides no warranty for the following specific products if such products are not installed by a qualified professional installer: DuraTech®, DuraPlus HTC®, DuraChimney® II, PelletVent Pro®, DirectVent Pro®, FasNSeal®, FasNSeal® W2, FasNSeal® Flex, and PolyPro®, and M&G DuraVent’s relining products including DuraLiner®, DuraFlex® (SW, Pro, 316, 304), and Ventinox®. For purposes of this warranty, a trained professional installer is defined as one of the following: licensed contractors with prior chimney installation experience, CSIA Certified Chimney Sweeps, NFI Certified Specialists, or WETT Certified Professionals.

DuraVent must be notified and given the opportunity to inspect defective product prior to replacement under the terms of this limited lifetime warranty. All warranty claims must be submitted with proof of purchase. Labor and installation costs are not covered under this warranty. To obtain warranty service contact: DuraVent Warranty Service, 877 Cotting Ct., Vacaville CA 95688, or call 800-835-4429.

WHERE LAWFUL, DURAVENT DISCLAIMS ALL OTHER WARRANTIES, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT WILL DURAVENT BE LIABLE FOR INCIDENTAL, CONSEQUENTIAL, PUNITIVE OR SPECIAL DAMAGES OR DIRECT OR INDIRECT LOSS OF ANY KIND, INCLUDING BUT NOT LIMITED TO PROPERTY DAMAGE AND PERSONAL INJURY. DURAVENT’S ENTIRE LIABILITY IS LIMITED TO THE PURCHASE PRICE OF THIS PRODUCT. SOME STATES DO NOT ALLOW LIMITATIONS ON IMPLIED WARRANTIES, OR THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATIONS AND EXCLUSIONS MAY NOT APPLY TO YOU. THIS LIMITED WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, AND YOU MAY ALSO HAVE OTHER RIGHTS THAT VARY FROM STATE TO STATE.

M&G DuraVent Limited Lifetime Warranty (PDF, 146KB )