Combustion, Ventilation, and Dilution Air

Air for combustion, ventilation, and dilution of flue gases must be provided for appliances installed in buildings by one of the methods described in Sections 304.5 through 304.9 of the 2023 Florida Fuel Gas Code.

Standard Method (304.5.1)

The minimum required indoor volume is calculated as:

Required Volume (ft³) = (Total Appliance Input in Btu/h ÷ 1,000) × 50

Known Air Infiltration Rate Method (304.5.2)

For appliances other than fan-assisted:

Required Volume = (Other Appliance Input ÷ 1,000) × (21 ÷ ACH)

For fan-assisted appliances:

Required Volume = (Fan Appliance Input ÷ 1,000) × (15 ÷ ACH)

Other Methods

Sections 304.6 through 304.12 cover alternative provisions including:

• Outdoor combustion air methods
• Combination indoor and outdoor air
• Engineered installations
• Mechanical combustion air supply
• Louvers, grilles, and duct requirements
• Protection from corrosive or flammable fumes and gases

All installations must comply with manufacturer instructions and the Florida Fuel Gas Code.

Reference: 2023 Florida Fuel Gas Code (IFGS) – Section 304