6.6103.1 Inline or Multi-Port

Desired Outcome: 
Inline or multi-port fan installed in accordance with specifications
The authority having jurisdiction may require that a licensed professional perform certain tasks outlined in this detail.

Wiring will be installed in accordance with original equipment manufacturer specifications, and local and national electrical and mechanical codes

Prevent an electrical hazard


Fan and service switch Service switch An electrical switch that controls the complete flow of electricity to a mechanical device will be accessible for maintenance, service, and replacement in accordance with applicable code or authority having jurisdiction

Ensure accessibility for maintenance

Fan mounting

Fan will be oriented with inlet toward the fan intake fitting

Fan will be oriented so the equivalent length of the duct run is as short as possible

Fan will be securely mounted in accordance with manufacturer specifications

Fan will be isolated from the building framing unless specifically designed to be directly attached

Fan will be installed remotely by ducting from supply register or grilles

Ensure short duct run to achieve optimum air flow

Ensure fan is mounted securely

Ensure fan housing or building framing does not shake, rattle, or hum when operating

Minimize noise

Damper (required for intermittent operation)

Damper will be installed to open in the direction of the desired flow

Damper will close when system is off

Ensure unrestricted air flow

Duct connections

Ducts will be connected and sealed to the intake fitting, fan, and register or grilles as follows:

  • Metal-to-metal or metal-to-PVC will be fastened with a minimum of three equally spaced screws
  • Flexible duct-to-metal or flexible duct-to-PVC will be fastened with tie bands using a tie band Tie band A strap, often made of nylon, that mechanically squeezes a flexible duct to a fitting. Must have a minimum performance temperature rating of 165° (per UL 181A-type test) and a minimum tensile strength rating of 50 pounds tensioning tool
  • Flexible duct between the cable tie and end of metal or PVC duct will be screwed
  • PVC-to-PVC materials will be fastened with approved PVC cement
  • Other specialized duct fittings will be fastened in accordance with manufacturer specifications

All joints and connections in ductwork will be fastened and sealed with UL UL Underwriters Laboratories 181B or 181B-M welds, gaskets, adhesive mastics, or mastic-plus- embedded-fabric systems

Provide desired air flow

Preserve integrity of the duct system and building envelope Envelope The separation between the interior and exterior environments of a building that includes a combination of air and thermal barrier


An accessible filter will be installed between the intake fitting and the fan

Contaminant removal will be consistent with at least minimum efficiency reporting value ( MERV MERV Minimum efficiency reporting value ) 6 or better when tested in accordance with ANSI ANSI American National Standards Institute, www.ansi.org / ASHRAE ASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers, www.ashrae.org 52.2

Filter or air cleaning systems that intentionally produce ozone will not be allowed

Ensure occupant health and safety

Preserve integrity of the building envelope Envelope The separation between the interior and exterior environments of a building that includes a combination of air and thermal barrier

Occupant education

Occupant will be educated on how and when to change filter

Ensure occupant health and safety

Boot to interior surface seal

All gaps between boot and interior surface will be air sealed

Gypsum edge will be wetted before applying water-based sealant

Sealants will be continuous and be in accordance with IRC IRC International Residential Code

Prevent air leakage around intake housing

Ensure a permanent seal to the building air barrier Air barrier The separation between the interior and exterior environments of a building that slows air flow to the point that no smoke movement is visible at 50 pascals of pressure difference across the boundary

Prevent a fire hazard