Preface

The vent sizing Tables, published in 1992 as Amendments to the CAN/CGA-B149.1-M91 Natural Gas Installation Code, and CAN/CGA-B149. 2-M91 Propane Installation Code, contained new venting criteria for Category I type appliances. These same Tables (unchanged) were included in subsequent editions of the Codes (ie. CAN/CGA-B149.1-M95 and CAN/CGA-B149.2-M95) and have been adopted by all provinces.

The General Venting Requirements accompanying these Tables includes a requirement (#14) that states ""if the desired vent height and vent connector rise and or lateral are between the Table entries, linear interpolation is permitted for calculation of the permissible appliance input ratings. Extrapolation beyond the table entries is not acceptable."" In response to requests from those using the Tables, the attached interpolations have been published. These Tables are intended to provide the user with a convenient way to size vent systems.

Please note that reference should be made to the complete B149 Installation Codes, any provincial regulations that apply, and the appliance manufacturers' installation instructions, to properly install the appliance and associated vent system.