Install a Dryer Vent Duct and Exterior Termination

A. Finished-Project Specification

Quantity: one complete dryer exhaust duct run from the transition-duct connection to one listed exterior termination, including all fixed-duct sections, supports, and the transition duct, sized and routed within the dryer manufacturer's approved diameter and maximum equivalent length.

B. Component Schedule

Component	Quantity	Material	Finished Size	Preparation
Fixed duct sections	Per route length	Rigid or semi-rigid metal, per manufacturer instructions	Diameter per dryer manufacturer instructions	Cut square, burrs removed, male ends oriented per airflow direction requirement
Elbows	Per route design	Matching rigid or semi-rigid metal	Diameter matching fixed duct	Oriented to minimize bend count and maintain full diameter
Transition duct	1	Manufacturer-approved flexible or semi-rigid connector	Per dryer manufacturer instructions	Positioned without crushing or kinking
Exterior termination	1	Listed dryer termination with backdraft damper	Diameter matching fixed duct	Installed with flashing integration and pest-screen restrictions observed
Duct supports	Per required interval	Manufacturer- or code-specified strap or hanger	Sized to duct diameter	Installed without creating low points

C. Material Takeoff

• Duct materials: rigid or semi-rigid metal duct sections and elbows sufficient for the measured route, sized to the dryer manufacturer's specified diameter.
• Connection materials: one listed transition duct, one listed exterior termination with backdraft damper, listed joint closures compatible with the duct material.
• Support materials: supports sufficient for the required interval across the full route length.
• Sealing materials: sealant compatible with the exterior wall or roof assembly for the termination penetration.

D. Fastener and Hardware Schedule

Joint	Fastener/Hardware	Requirement
Fixed-duct section joints	Listed closure method per duct manufacturer	No fastener may project into the airstream where prohibited; male end points in direction of airflow where required
Transition-to-appliance connection	Manufacturer-specified clamp or closure	Secured without crushing the transition duct
Duct supports	Strap or hanger fasteners sized to framing	Installed at the required interval without creating low points or sag
Exterior termination	Manufacturer-specified fasteners	Termination secured, flashing integrated with the building envelope, damper verified free-moving

E. Acceptance Standards

Check	Standard
Route	Dedicated to the dryer exclusively; no connection to another exhaust or HVAC system at any point
Equivalent length	Within the dryer manufacturer's stated maximum after applying bend penalties
Fasteners	No fastener projects into the airstream where prohibited
Supports	Installed at the required interval with no low points or excessive sag
Termination	Listed type, functioning damper, flashing integrated, no unapproved lint-trapping screen
Airflow test	Unobstructed warm airflow and free damper movement verified during an authorized dryer cycle
Leakage and lint	No visible leakage, heat damage, vibration, or lint escape at any joint or the termination

F. Preparation and Route Layout

1. Review the dryer manufacturer instructions, approved duct material, diameter, maximum equivalent length, bend allowances, transition duct, termination, and clearances. Record each value on the Route Definition Record before proceeding.
2. Confirm that the route is dedicated to the dryer and does not connect to another exhaust or HVAC system. Verify this against the Chapter 1 system map.
3. Inspect the route for framing, electrical, plumbing, gas piping, insulation, fire separations, and access. Mark and avoid every identified conflict before cutting.
4. Mark the shortest approved route and each support point. Record the marked route and support locations on the worksheet.
5. Confirm that concealed duct material is rigid or semi-rigid metal as required and that plastic or foil accordion duct is not used where prohibited. Stop and correct the material selection before continuing if this is not met.

G. Duct Assembly and Support

1. Cut rigid duct sections square and remove sharp burrs. Verify each cut edge is free of burrs before joining.
2. Orient joints so male ends point in the direction of airflow where required. Confirm orientation at each joint before securing.
3. Join sections using the approved listed closure method. Verify full engagement at each joint.
4. Do not install screws or fasteners projecting into the airstream where prohibited. Inspect the interior of each joint after fastening.
5. Support the duct at the required intervals without creating low points. Verify support spacing against the manufacturer or code requirement.
6. Minimize bends and maintain full duct diameter. Recheck the calculated equivalent length after assembly against the manufacturer's maximum.
7. Maintain required clearances from combustible materials and heat sources. Verify clearance at every point the duct passes near a heat-producing component.

H. Exterior Termination

1. Prepare the exterior wall or roof opening using the approved structural and envelope procedure. Verify the opening size matches the termination's rough-in requirement.
2. Install the listed dryer termination without an unapproved screen that can trap lint. Confirm the termination model is listed for dryer exhaust use.
3. Integrate flashing with the building envelope. Verify shingle-lap or wall-drainage order is correct before sealing.
4. Verify that the damper opens freely and is accessible for cleaning. Test the damper by hand before final assembly.
5. Seal duct joints and the building penetration using compatible materials. Confirm sealant compatibility with the exterior assembly material.

I. Appliance Connection and Testing

1. Install the manufacturer-approved transition duct between dryer and fixed duct. Confirm the transition duct type matches the manufacturer's specification.
2. Position the dryer without crushing or kinking the transition duct. Verify clearance behind the appliance before final positioning.
3. Confirm access for future cleaning and appliance service. Verify the transition duct and nearest fixed-duct joint remain reachable.
4. Operate the dryer in an authorized test mode. Confirm the appliance is otherwise ready for normal operation before starting the test.
5. Verify exterior damper opening and unobstructed warm airflow. Observe the termination from outside during the test cycle.
6. Inspect joints, transition duct, termination, and surrounding surfaces for leakage, vibration, heat damage, or lint escape. Record any deficiency found.
7. Measure or document equivalent length as required. Confirm the final as-built value against the manufacturer's maximum.
8. Correct restricted, crushed, leaking, or unsupported sections. Re-run the affected test after any correction.
9. Document materials, route, bends, termination, and test result. Complete the Dryer Vent Installation Worksheet before closeout.