Demand-Controlled Ventilation Requirements Proposed for ASHRAE
Requirements for systems that use optional demand-controlled ventilation strategies are being proposed for ASHRAE’s ventilation standard.
Requirements for systems that use optional demand-controlled ventilation strategies are being proposed for ASHRAE’s ventilation standard.
ANSI/ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality, sets minimum ventilation rates and other requirements for commercial and institutional buildings.
Seven proposed addenda to the standard currently are open for public comment.
Currently, the dynamic reset section of the standard allows designers to use optional controls to reset outdoor air intake flow and/or zone minimum airflow as conditions within the system change. For instance, it would allow a ventilation-system control approach that alters outdoor air intake flow based on time-of-day, if variations in zone population follow a predictable schedule, according to Dennis Stanke, committee chair.
Proposed addendum 62g provides more specific requirements for such optional system controls, especially those historically called “demand controlled ventilation” (DCV) and based on the use of CO2 levels, as they relate to outdoor airflow rates.
For example, the addendum would require that optional DCV controls provide no less than the “area outdoor air rate” listed in Table 6-1, and that such controls maintain the minimum outdoor air intake flow no lower than the exhaust airflow rate required by Section 6.2.8, Stanke says.
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