How does 62.1 address fume hoods and local exhaust?

• A. Local exhaust and dedicated ventilation are used to limit contaminants at the source, especially in labs.
• B. They are optional and rarely used in any space.
• C. They replace general ventilation entirely.
• D. They should only be used in residential buildings.

Answer: (A)

The main idea is that ASHRAE 62.1 uses local exhaust, including fume hoods, as a source-control measure to limit contaminants right where they originate. By capturing emissions at the source, these systems prevent pollutants from spreading into occupied spaces, which is especially important in laboratories where volatile substances are used. This approach also helps reduce the amount of outdoor air needed for dilution, improving energy efficiency. But local exhaust does not replace general ventilation; it complements it. General ventilation continues to supply outside air to dilute contaminants that aren’t captured at the source and to ventilate areas without local exhaust. They are applicable beyond residential buildings and are standard practice in labs and other spaces that require source containment.