The minimum required clearance from a single-wall exhaust flue at an oil furnace to combustibles is _____ inches.

The minimum required clearance from a single-wall exhaust flue at an oil furnace to combustibles is 9 inches. This clearance is established to ensure safety by reducing the risk of fire hazards. Single-wall exhaust flues, which are used for venting exhaust gases from oil furnaces, can get quite hot, and having a proper clearance from combustible materials is critical to prevent any potential ignition.

The 9-inch clearance provides a sufficient buffer zone that allows heat to dissipate and prevents any combustibles, such as wood framing or insulation, from being exposed to excessive heat. Adhering to this clearance is crucial for maintaining safe operating conditions and ensuring compliance with local building codes and manufacturer specifications. Overall, this standard helps to ensure both the safety and efficiency of the heating system.