Exterior Intakes

Detail ID 6.0101.3
Topic
Infrastructure
Subtopic
Components
Desired Outcome

Appropriate, safe, weather-tight, pest-resistant and effective intake fittings with unrestricted air flow

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

Specifications

  • SF
  • MH
  • MF
Specification Objective

Select intake fitting:

that is appropriate for regional weather conditions and installation location

with an integrated collar at least the same diameter as the exhaust duct outlet

with an integrated pest screen with holes no less than 1/4" and no greater than 1/2"

in very cold climates that have no backflow dampers or use backflow dampers that resist freezing

Appropriate, safe, and weather resistant termination

  • SF
  • MH
  • MF
Specification Objective

Damper must open in the direction of the desired flow

Damper will close when system is off

No damper is required if the system operates continuously

Prevent unwanted air movement while not restricting desired air flow

  • SF
  • MH
  • 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

  • SF
  • MH
  • MF
Specification Objective

Cut hole no larger than a 1/4" greater than the termination fitting

Weather seal and flash the exterior fitting

Mechanically fasten termination in place following manufacturer specifications

Do not inhibit damper operation if included in termination

Weather-resistant, durable, and effective installation

  • SF
  • MH
  • MF
Specification Objective

If termination collar is larger than intake duct install a rigid metal transition

Effective termination connection

  • SF
  • MH
  • MF
Specification Objective

Label intake fitting: "ventilation air intake"

Prevent fitting restriction

  • SF
  • MH
  • MF
Specification Objective

Seal all duct connections with UL 181B or 181B-M listed materials (e.g., mastic, tape)

Airtight duct connections

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