Gas-fueled appliances shall have a minimum clearance from the flue outlet.

• A. 12 Inches
• B. 24 Inches
• C. 18 Inches
• D. 6 Inches

Answer: (C)

Keeping a safe distance between the flue outlet and nearby materials is about preventing heat from causing fires and ensuring proper venting. The exhaust from a gas‑fired appliance is hot and can transfer enough heat to ignite combustibles or damage surfaces if they’re too close. A minimum clearance creates a cushion so heat doesn’t reach walls, cabinets, or other combustible items, and it also helps keep the vent path clear for efficient exhaust and for maintenance access. Codes set this distance to balance safety with practical installation, accounting for the appliance’s heat output and the surrounding environment. If space makes meeting the clearance difficult, the installation must use approved shielding or relocate the appliance to satisfy the requirement and maintain safe venting.