A duct furnace flue pipe must provide a clearance to combustibles of how many inches?

The appropriate clearance to combustibles for a duct furnace flue pipe is 18 inches. This clearance is established to minimize the risk of fire hazards by ensuring that any heat radiating from the flue pipe does not ignite surrounding combustible materials.

In setting codes and regulations, safety standards are a critical concern, particularly in residential and commercial heating installations. The 18-inch requirement reflects a balance between safety and practicality, ensuring that the installation remains effective while being mindful of potential fire risks. Compliance with this clearance helps ensure that the system operates safely over time, reducing the likelihood of dangerous situations arising from excessive heat exposure to flammable materials.