6.6003.4 Multi-Port System

Topic: 
Exhaust
Subtopic: 
Fans
Desired Outcome: 
Multi-port fans installed to specification
Note: 
The authority having jurisdiction may require that a licensed professional perform certain tasks outlined in this detail.
TitleSpecification(s)Objective(s)
6.6003.4a
Wiring

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

Prevent an electrical hazard

6.6003.4b
Access

Fan and access switch shall be accessible for maintenance according to NFPA NFPA National Fire Protection Association, www.nfpa.org 70 National Electric Code or local authority having jurisdiction

Achieve designed exhaust flow from desired locations to the outside

6.6003.4c
Fan mounting

Fan outlet will be oriented toward the final termination location

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

Fan will be mounted securely 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 intake grilles

Ensure short duct runs to achieve optimum air flows

Ensure mounting is installed securely

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

Minimize noise

6.6003.4d
Backdraft dampers (required in intermittent systems)

A backdraft damper Backdraft damper A damper that allows air to flow in only one direction will be installed between the fan and the exterior unless the system operates continuously

A backdraft damper Backdraft damper A damper that allows air to flow in only one direction will be installed in any duct serving any room with a separate exhaust (e.g., dryer)

Prevent reverse air flow when the system is off

Prevent spread of contaminants between rooms

6.6003.4e
Combining intake ducts

All individual exhaust intake ducts will be combined on the upstream side of fan (e.g., Y-fitting, T-fitting, collector box) with the exception of dryer, kitchen, and garage

Exhaust air from desired locations to outside

6.6003.4f
Duct connections

Ducts will be connected and sealed to applicable intakes, collector box, fan, and termination fitting

Ducts will be connected and sealed as follows:

  • Round metal-to-metal or metal-to-PVC will be fastened with a minimum of three equally spaced screws
  • Other metal-to-metal or metal-to-PVC connections will be securely fastened and sealed with welds, gaskets, mastics (adhesives), mastic-plus-embedded-fabric systems, or tapes
  • 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
  • PVC-to-PVC materials will be fastened with approved PVC cement
  • Other specialized duct fittings will be fastened in accordance to manufacturer specifications
  • In addition to mechanical fasteners, duct connections will be sealed with UL UL Underwriters Laboratories 181B or 181B-M listed material

Exhaust air from desired locations to outside

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

6.6003.4g
Insulation

All components outside of the thermal envelope Envelope The separation between the interior and exterior environments of a building that includes a combination of air and thermal barrier will be insulated to a minimum of R-8 or equivalent to local code

Exception: If system operates continuously, fan housing need not be insulated

Preserve integrity of the duct system

6.6003.4h
Boot to interior surface seal

Sealants will be compatible with their intended surfaces

Sealants will be continuous and meet fire barrier specifications

Prevent air leakage around boot

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

6.6003.4i
Air flow

Air flows in CFM CFM Cubic feet per minute will be measured and adjusted to meet the design requirements

Exhaust sufficient air from desired locations to outside

6.6003.4j
Preventing air leakage caused by exhaust fans

Air leakage into the house from other spaces will be prevented (e.g., garages, unconditioned crawl spaces, unconditioned attics)

Ensure occupant health and safety

6.6003.4k
Combustion safety

Pressure effects caused by fans will be assessed and corrected when found outside of combustion safety standards

Ensure safe operation of combustion appliances