How close can the exterior air outlet be located to the firebox opening on the floor?

The minimum distance between the exterior air outlet and the firebox opening is crucial for ensuring proper ventilation and safety in a commercial building. A distance of 24 inches helps to prevent issues such as backdrafts and ensures an adequate supply of combustion air. This spacing allows for the necessary clearance to minimize the risk of heat transfer and ensures that the air supply is not adversely affected by the draft patterns created by the firebox.

Having the exterior air outlet too close—such as at 6 or 12 inches—could lead to safety hazards, such as inadequate ventilation for combustion or potential flue gas re-entry into the building. A distance of 36 inches, while it may provide additional safety, is typically excessive according to most code requirements, as 24 inches usually provides sufficient separation. Understanding this standard is vital for maintaining safety and efficiency in building operations.