Venting Gas Appliances
On the installation of natural draft water heater vents and draft hoods.
Follow Manufacturer installation instructions
Always follow manufacturer instructions on the installation of draft hoods and water heater vents.
M2004.1 of the 2018 International Residential Code (Pg 526) states "Water heaters shall be installed in accordance with Chapter 28, the manufacturer's instructions and the requirements of this code"
Page 7, The last paragraph states "Draft Hood Connectors must be attached to the appliance outlet (draft hood) with screws"
Page 3, Step 3, Section C states "Secure the vent pipe to the draft hood with self drilling screws"
When a coupling is used for B-Vent connections to the draft hood, Page 4 states "Note: be sure to secure connections as described in step 3"
Secure the vent pipe to the draft hood as instructed by the manufacturer. As well as follow all other manufacturer instructions.
Secure the draft hood to the water heater as it is designed, using the draft hood supplied by the manufacturer of the water heater.
Use sheet metal screws to attach different sections of single wall vent pipe. Pg 595 G2427.10.6 of the IRC, or 12.11.6 Joints from the 2018 National Fuel Gas Code "Venting of Appliances".
Use an adapter to connect B-vent to the draft hood.
Connect sections of pipe as they are designed for B-Vent (slide together and twist).
For single wall vent pipe, attach different sections together with 3 sheet metal screws.
Allow at least a 12" verticle rise from the draft hood before any turns in the vent pipe where possible.
Connect single wall to double wall vent pipe using an adapter and following manfacturer instructions
Connect any sections of vent pipe with tape only
Use a 3 inch vent for a 4 inch draft hood
Reduce the vent size from 4 inch to 3 inch vent pipe.
Allow single wall vent pipe to pass through any unfinished area (attic, crawlspace, etc) or a wall.
Penetrate the inner lining double wall (B-vent) with any screws EXCEPT at the transition
from the appliance draft hood outlet, flue collar, or single-wall metal connector to a double-wall vent.
(12.7.2 paragraph 4, 2018 National Fuel Gas Code)