Ventilation for Gas Fired Equipment

Gas fired equipment requires a continuous air flow in order to support the combustion process. Ventilation for gas fired equipment is the process of replacing the air necessary for proper equipment operation. The amount of ventilation provided must equal or exceed the air flow demands for all of the gas fired equipment within a structure. The requirements for combustion and dilution air for gas-fired appliances shall be in accordance with the Fuel Gas Section of the Florida Building Code. 

How much air is needed for the proper ventilation of gas fire equipment and where can we get it?  Combustion, Ventilation, and Dilution air of flue gases shall be provided to the appliances through interior spaces, exterior spaces, or a combination of the two. 

Indoor Combustion Air: Utilizing the standard method, the minimum required volume shall be 50 cubic feet per 1,000 Btu/h of the appliance input rating. Openings can be used to connect multiple indoor spaces together.

Outdoor Combustion Air: May be provided through openings to the outdoors utilizing either a two-permanent-opening method or a one-permanent opening method. In the two-permanent-opening method, two openings, one commencing within 12 inches of the top and one commencing within 12 inches of the bottom of the enclosure, shall be provided. Where communicating directly with the outdoors, or communicating through vertical ducts, each opening shall have a minimum free area of not less than 1 square inch per 4,000 Btu/h of total input rating of all appliances in the enclosure. Utilizing the one-permanent-opening method, one opening, commencing within 12 inches of the top of the enclosure, shall be provided. The opening shall directly communicate with the outdoors, or through a vertical or horizontal duct, to the outdoors and shall have a minimum free area of 1 square inch per 3,000 Btu/h of the total input rating of all appliances located in the enclosure.