How long must the outdoor air ventilation system operate in a 4-hour period for certain Group R occupancies?

For certain Group R occupancies, the requirement that the outdoor air ventilation system must operate for 1 hour within a 4-hour period is grounded in the need to ensure proper indoor air quality and sufficient ventilation for the occupants. This regulation acknowledges that adequate ventilation is crucial in residential settings, where varying occupancy levels might lead to fluctuating air quality needs.

Operating the ventilation system for 1 hour during each 4-hour period helps to effectively introduce fresh air, dilute indoor pollutants, and maintain a healthy living environment, especially in spaces like apartments or dormitories where people may gather. This balances energy efficiency with public health considerations, ensuring that the air remains fresh without requiring constant ventilation, which may lead to energy waste and increased operational costs.

The specification of 1 hour provides a practical and manageable approach for ventilation schedules that can be integrated easily into automated building management systems, resulting in an effective compliance strategy for those managing these types of properties.