According to ASHRAE Standard 62.1, how often should the outdoor air quantities to air handlers over 2,000 cfm be measured?

• A. Every year
• B. Every 5 years
• C. Every 2 months
• D. Every 10 years

Answer: (B)

The requirement focuses on periodic verification of the actual outdoor air delivered by large air handlers. ASHRAE 62.1 specifies that for air handlers over 2,000 CFM, the outdoor air quantities should be measured at least every five years. This interval balances the need to catch drift from sensors, damper movements, or duct changes with the practical effort and cost of testing. More frequent checks aren’t mandated for this item, while waiting longer could allow unnoticed deviations from the intended ventilation rates.