If a contaminant source is within 10 feet of an intake opening, how far must the opening be below the contaminant source?

The correct answer is that the opening must be at least 2 feet below the contaminant source when it is within 10 feet of an intake opening. This requirement is based on best practices in HVAC system design and public health considerations. The primary aim is to ensure that any potential contaminants that could be released into the air do not find their way into the HVAC intake system.

Maintaining a vertical distance of 2 feet helps reduce the risk of any contaminants from the adjacent source being drawn into the system, as air tends to move in a downward direction due to gravity. This spacing allows for a buffer zone that can trap or disperse airborne contaminants before they reach the intake. The 2-foot requirement aligns with certain codes and standards intended to promote safe and efficient operation of HVAC systems, particularly in areas where contaminants may be prevalent. Such regulations are crucial for protecting indoor air quality and ensuring the health and safety of building occupants.

Positions that suggest smaller distances, such as 1 foot, do not provide sufficient buffer against potential contamination, while options for greater distances, such as 3 or 4 feet, may be unnecessarily conservative in many situations unless specific conditions warrant tighter controls. Therefore, the 2-foot guideline strikes an appropriate balance between practical engineering and