1. Installing wall terminations for exhaust fan vent

• Follow steps 1a-1h to install a wall termination for an exhaust fan vent.

1a. Termination location

• Terminations will be ducted to the outdoors.

• Ensure termination does not exhaust into a carport or buffered space.

• Ensure termination has appropriate clearances from other openings into the home. Terminations must be at least 3' from operable openings into the building, 10' from mechanical air intakes, 3' from property lines, and must have appropriate clearances from Category IV appliance vent terminations, to prevent exhaust from reentering house.

1b. Termination pest screen

• Vent terminations shall have screen material with no less than 1/4" and no greater than 1/2" hole size in any direction to prevent pest entry.

1c. Identify location

• Follow instructions in work order and Identify where to install the termination in attic, floor or crawlspace.

• Note the location of structural members, and plumbing and electrical lines.

1d. Trace hole

• Locate where to install the termination on the exterior of the home and trace outline of duct avoiding structural members and utilities.

1e. Cut hole

• Determine vent diameter and cut hole in exterior wall slightly larger, but not more than 1/4" larger, than the outer diameter of the vent shroud on the termination.

• Take care not to cut any plumbing or electrical lines.

1f. Drill hole

• If installing termination through masonry or stone, use a core drill to cut hole.

1g. Install flashing

• Whenever possible, install flashing under cladding to direct water away from penetration and preserve the integrity of the building envelope.

1h. Install collar

• Install a collar the same diameter as the outlet on the fan, or larger.

• If collar is larger than exhaust fan outlet, a rigid transition shall be used.

1i. Install vent termination on gable or wall

• Position vent termination flush against exterior.

• Orient to allow damper(s) to close when not in use.

• Secure to house using 4 or more exterior grade fasteners.

1j. Seal termination

• Seal gap between termination and exterior of home with exterior grade caulk to prevent water intrusion.

2. Installing roof terminations for exhaust fan vent

• Follow steps 2a-2h to install a roof termination for an exhaust fan vent.

2a. Termination location

• Terminations will be ducted to the outdoors.

• Ensure termination does not exhaust into a carport or buffered space.

• Ensure termination has appropriate clearances from other openings into the home.

• Terminations must be at least 3' from operable openings into the building, 10' from mechanical air intakes, 3' from property lines, and must have appropriate clearances from Category IV appliance vent terminations, to prevent exhaust from entering house.

2b. Termination pest screen

• Vent terminations shall have screen material with no less than 1/4" and no greater than 1/2" hole size in any direction to prevent pest entry.

2c. Identify location

• Identify location from inside the attic.

• Choose location to minimize length of duct, turns and bends.

• Trace outline on the roof sub-straight.

2d. Install marking screws

• Drive a couple screws thru the sub-straight and thru roofing to transfer the location to the exterior.

2d. Continued . . .

2e. Transfer outline

• Outside the house, trace the outline of the duct onto the roofing, using the pilot holes as a guide.

2f. Cut hole

• From the exterior, cut out the hole for the duct slightly larger, but not more than 1/4" larger, than the outer diameter of the vent shroud on the termination.

• Take care not to cut any structural members or plumbing or electrical lines.

2g. Pry shingles

• For roof holes, pry up and break shingle tab seals around the top half of the hole to allow for installation of roof termination.

2h. Trim shingles

• Trim shingles to lay flat and fit tightly around roof termination in a manner that will direct water away from termination, and prevent water intrusion into the building.

2i. Install roof vent cap

• Install a vent cap under shingles and directly over the hole.

• Trim shingles as necessary to fit vent cap.

• Tuck top of roof termination flashing under shingles, and lay bottom of termination flashing on top of shingles to prevent water intrusion.

2j. Seal vent termination

• Seal the underside of the vent cap flange, nail holes, and shingles with roof sealant.

2k. Fasten vent termination

• Secure to roof using 4 or more roofing fasteners.

• Top fasteners should be installed under shingles.

2l. Seal top of vent termination

• Seal the nail holes, and edges of shingles with roof sealant.

3. Installing exhaust fans

• Follow steps 3a-3h to install an Exhaust Fan.

3a. Locate fan

• Follow work order to select exhaust fan location.

3b. Avoid wires, pipes and joists

• Be careful to avoid structural members and electrical and plumbing lines.

3c. Trace outline

• Inside the home, trace the outline of the fan on the ceiling.

• If location was selected from attic, use pilot holes as a guide.

3d. Cut hole

• From inside the home, carefully cut the fan hole no greater than 1/4" greater than assembly.

• Support the piece while cutting to prevent breaking larger hole.

3e. Install fan

• Install the fan according to the manufacturers specifications. Aim the exhaust port in the direction of the termination.

3f. Backdraft damper

• A backdraft damper will be installed between the outlet side of the fan and the exterior to prevent reverse air flow when the fan is off.

• Ensure fasteners do not inhibit damper operation.

3g. Install electrical

• Connect fan to commercial electricity.

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

• Notice:  This must be done by a Licensed Electrician.

3h. Air seal

• Caulk or mastic all of the cracks between the drywall and the housing and all holes in the housing unit.

4. Install ducting

• Follow steps 4a-4d to install a rigid metal or PVC duct.

• Our program standard is to use rigid ducting wherever possible because it is more durable, offers higher efficiency, and provides quieter ventilation. 

• Flexible ducting may ONLY be used when rigid ducting cannot be safely and effectively installed, and flexible ducting can be.

4a. Select duct sizing

• Refer to manufacturer's specifications to determine correct duct sizing.

• Duct must be sized  to allow for air flow needed and to prevent excessive noise.

4b. Plan duct run

• Design a rigid metal or PVC duct that will connect the exhaust fan to the exterior termination.

• Duct sizing, overall duct length and number of elbows should be within allowable manufacturers specs, and should be ran in the most direct route to minimize total duct length.

4c. Connect duct

• Cut and connect each piece of duct to allow for maximum air flow.

• For metal duct connect with the crimped end furthest away from the exhaust fan to maximize flow of exhaust fan.

4d. Fasten duct

• For metal duct Install 3 or more duct screws evenly spaced around the diameter of the duct at each connection.

• For PVC duct prime and glue all connections.

• All flexible duct connections must be secured to a metal collar or fitting.

  • To make a proper flex duct connection, first slide the inner liner of the duct over the metal collar or fitting. Secure it tightly with a clamp so it cannot slip off. Once clamped, seal the connection with tape with UL181 rating or mastic to prevent air leaks.  

• At no time can you reduce the size of the ducting smaller than what the collar is on the appliance.

4e. Seal duct

• Use mastic or UL181 Listed Tape to seal all seams and connections on metal duct.

5. Insulate duct

• Follow steps 5a-5e to insulate duct.

5a. Insulate duct

• Measure and cut insulated flex duct to cover duct between the exhaust fan and the termination.

• Inside diameter of flex duct should be about 1" larger than the outer diameter of the duct.

• The R-value of the insulation should be an R-8 or equivalent to local codes.

5b. Slip insulation over duct

• Slip the insulation over the duct and stretch from end to end to ensure proper fit and coverage.

5c. Connect duct to fan and termination

• Connect the duct to the exhaust fan and to the exterior termination.

5d. Connect outer sleeve

• Slide outer sleeve over duct boot, adjust insulation to allow for full coverage, and secure outer sleeve with zip tie.

6. Support duct

• Support rigid ducts every 10' or less using 1/2" or wider material.

• If flexible ducting was allowed in step 4, it must be supported every 4 feet or less with a minimum of 1.5 inch wide support material. This support ensures the duct remains fully extended, preventing kinks and airflow restrictions. Additionally, the duct should not sag more than 1/2 inch per foot between supports and should maintain a bend radius of at least one duct diameter to avoid restricting airflow.

7. Test airflow

• Use flow meter to test fan flow to ensure it meets flow requirements.

8. Client education

• Educate client on the proper use and settings of the fan.

9. Worst Case Draft test

• Conduct a Worst Case Draft (WCD) test to verify Category I, II, and III appliances are venting safely before leaving home for the day.

• Testing shall be recorded using the Utah WAP Worst Case Draft Test form.

Manufacture specs

• Manufacture specs must be followed at all times.

• Ventilation rates must meet ASHRAE 62.2 as calculated using the Utah WAP ASHRAE Calculator or other approved tool.