Using tables from the National Fuel Gas Code or our Sizing & Application Guide, determine the diameter of venting required. The Sizing & Application Guide also offers tips on good design including multi-appliance system sizing and design. The System Design and Installation Guide is an additional resource.
Required by Los Angeles Code and UMC
The Type BW attic shield is used on a single-story building or on the top story of a multi-story building for Type BW gas vent. A 26-gauge galvanized sleeve should extend from the top of the ceiling plate into the attic. A Type BW attic shield is required by Los Angeles Code and UMC.