In ASHRAE 62.1, what is the role of the VRP versus IAQP?

• A. VRP defines the minimum ventilation rate; IAQP allows alternative strategies to meet target IAQ.
• B. VRP is optional and IAQP is mandatory.
• C. IAQP defines minimum ventilation; VRP optimizes IAQ targets.
• D. They refer to energy calculations only.

Answer: (A)

In ASHRAE 62.1, two paths exist to ensure acceptable indoor air quality. The ventilation-rate procedure provides a prescriptive rule: it sets the minimum outdoor air (ventilation) rates for each space to dilute contaminants. The IAQ procedure, by contrast, is a performance-based option that lets you meet the IAQ targets using alternative strategies—such as higher-efficiency filtration, source control, air cleaning, or different ventilation rates—as long as the resulting indoor air quality meets the targets for the contaminants of concern. So the first path establishes a minimum ventilation rate, while the second path offers flexibility to achieve the same IAQ goals through other design measures. This is not about energy calculations alone, and IAQP is not mandatory in every project—the VRP remains the baseline option, with IAQP available as an alternative.