What is the minimum vertical clearance above the air intake required for exhaust vents?

What is the minimum vertical clearance above the air intake required for exhaust vents?

• A. 3 m
• B. 4.5 m
• C. 2 m
• D. 6 m

Answer: (B)

Exhaust vents must be kept far enough above any air intake so exhaust gases don’t get drawn back into the building. The air intake supplies air for ventilation or combustion, and if an exhaust vent is too close, wind or stable air can push the plume toward the intake, bringing odor, moisture, or dangerous gases like carbon monoxide inside. Setting a vertical clearance of 4.5 meters gives enough distance for the exhaust plume to disperse and dilute before it could reach the intake, reducing the risk of recirculation. Smaller clearances increase the chance of backdrafts, while larger ones aren’t required by the standard and add unnecessary height.

Exhaust vents must be kept far enough above any air intake so exhaust gases don’t get drawn back into the building. The air intake supplies air for ventilation or combustion, and if an exhaust vent is too close, wind or stable air can push the plume toward the intake, bringing odor, moisture, or dangerous gases like carbon monoxide inside.

Setting a vertical clearance of 4.5 meters gives enough distance for the exhaust plume to disperse and dilute before it could reach the intake, reducing the risk of recirculation. Smaller clearances increase the chance of backdrafts, while larger ones aren’t required by the standard and add unnecessary height.