Multi-Story Passive System

Detail ID 6.0304.1
Whole-Building Ventilation
Passive Ventilation
Desired Outcome

Efficient and effective passive ventilation system

SF Single Family Site-Built Housing
MH Manufactured Housing
MF Multifamily Housing


  • MF
Specification Objective

Install intake to pull air from the outdoors, which does not include unconditioned spaces such as attics and crawl spaces that are ventilated with the outdoors

Install intake:

A minimum of 6" from grade;

A minimum of 10' from contaminant sources or exhaust outlets;

Above local snow or flood line;

A minimum of 18" above an asphalt based roof;

Never on a flat roof

Unrestricted entry of contaminant-free air

  • MF
Specification Objective

Install corrosion resistant screen, louver, or grille material over exterior terminations with a hole size of no less than 1/4" and no greater than 1/2" in any direction

Prevent pest entry while allowing proper air flow.

  • MF
Specification Objective

System must contain a backdraft damper between all exterior terminations/intakes that only allows air flow in the desired direction

A system of one or more backdraft dampers shall be installed to isolate each dwelling unit from the common duct when the system is not operating

Prevent unwanted air movement

  • MF
Specification Objective

Intakes/supplies in dwelling units must minimize potential occupant discomfort and/or drafts

Minimize client discomfort

View Sub-Topic:
Passive Ventilation