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ASHRAE Indoor Air Quality Standard Reduces Excess Ventilation

October 25, 2013 By Linda Hardesty

Energy Manage ASRAE logoThe newly published 2013 version of ASHRAE’s indoor air quality standard contains several revisions to allow designers and building operators to provide adequate ventilation airflow to occupants while reducing excess ventilation and the associated energy consumption.

ANSI/ASHRAE Standard 62.1-2013, Ventilation for Acceptable Indoor Air Quality, sets minimum ventilation rates and other requirements for commercial and institutional buildings.

The 2013 standard combines the 2010 standard and 10 published addenda to that edition, providing a consolidated standard. Significant changes include:

  • Table 6-2, Zone Air Distribution Effectiveness is modified to increase the ventilation effectiveness of underfloor air distribution systems that meet certain conditions.
  • Requirements for the quality of water used in humidification systems are modified and clarified.
  • Building level pressurization requirements are clarified, including adding a definition of “exfiltration.”
  • A performance alternative to the prescriptive exhaust rates is added. This approach differs from the Indoor Air Quality Procedure, the existing performance-based method for setting supply ventilation rates, in that monitoring of the concentrations of contaminants of concern is required and provides the basis for control of exhaust flow rates.
  • Some changes to the ventilation rates and space types are made. These add refrigerated warehouses and change the ventilation rate for sports related spaces to include a per occupant component which then allows the use of demand controlled ventilation in these spaces.
  • The filtration requirement on air entering wetted cooling coils has been modified to change the MERV rating from 6 to 8. This change will reduce potential for particulate deposition on the coils that could lead to biological or other contamination on the coils.
  • Toilet exhaust air that is cleaned to Class 1 may be recirculated.

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