How far must combustible materials be from the inside surface of the nearest flue lining in masonry chimneys constructed as part of masonry or concrete walls?

Combustible materials must be placed a minimum of 12 inches from the inside surface of the nearest flue lining in masonry chimneys that are part of masonry or concrete walls to ensure fire safety and compliance with building codes. This distance is essential because it helps prevent the risk of heat transfer from the flue to the combustible materials, which could lead to ignition and potentially cause a fire.

By maintaining this distance, the integrity of the chimney system is preserved, and the risk of fire hazards is minimized. This regulation is grounded in fire safety standards, which aim to protect occupants and property from the dangers associated with improperly installed or maintained flue systems.