Simpson Dura-Vent's Type B Gas Vent system is for 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 for a wide range of applications, including: natural gas fireplaces, gas-fired furnaces, boilers, water heaters, and wall or space heating applications.
Simpson Dura-Vent's Type B Gas Vent systems are UL Listed to UL 441 and UL 1777 (MH6357). ULC Listed to ULC S605 (CMH1276 & CMH1407).
Refer to the Typical Installation drawings below to select the appropriate component parts for your installation.
Type B Gas Vent Installation Key
|1. DuraCap||10. Female Flex Adapter||19. Oval Tee|
|2. Storm Collar||11. Male Adapter||20. Oval Tee Cap|
|3. Roof Flashing||12. Double-Wall Wye||21. Oval Tee Support|
|4. High-Wind Cap||13. Pipe Collar||22. Oval Firestop Spacer|
|5. Round Pipe||14. Increaser||23. DuraConnect II|
|6. Elbow||15. Draft Hood Connector||24. DuraFlex AL Length|
|7. Tee||16. Square Firestop Support||25. DuraFlex Motar Sleeve|
|8. Tee Cap||17. Oval Pipe||26. DuraFlex AL Coupling|
|9. Increaser Tee||18. Oval to Round Adapter|
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.
Gas Vent Specification Chart
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 2. (L202). 14"-16" Require screws.
3. When oval is used on wall furnaces, minimum height required from bottom of furnce 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.