A project involves adding a new mechanical ventilation system to an existing building. The existing air handling unit will be reused. According to the CMC, what is the minimum MERV rating required for the filters in this reused unit serving regularly occupied areas?

• MERV 11, as a compromise between old and new standards.
• MERV 8, as a common standard for existing systems.
• The MERV rating is not specified for existing equipment; the exception applies.
• MERV 13, as required for all new and existing equipment.