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DS 1.0—Introduction
Performance-based duct testing shall be performed only by technicians certified by Performance Tested Comfort Systems (PTCS) or Oregon Department of Energy (ODOE). All duct testing shall be performed, or inspected for material and workmanship compliance by technicians certified as duct sealers, by PTCS or ODOE.
DS 1.1—Measurement
Measurements of duct leakage and leakage reductions shall be performed to the requirements of PTCS or ODOE. All leakage and reduction tests shall be Duct Leakage to Outside, tested at 50 Pascals of pressurization with respect to outside.
Duct leakage shall be measured before sealing (Pretest) and after sealing (Post test). Reductions in duct leakage shall be measured as follows:
Pretest - Post test = Leakage Reduction
In extreme cases, duct system leakage may be tested as a split system (testing supply leaks only). Both Pretest and Post Test shall be conducted as a split system. When a system is sealed as a split system, returns in garages shall be sealed to prevent carbon monoxide and other pollutants from entering the duct system.
DS 1.2—Duct Testing Replication Standard
When Quality Control (QC) inspection is performed on a duct sealing job, the QC post test CFM 50 shall be within 20% or 100CFM, which ever is less, of the contractors post test CFM 50 as recorded on the contractor’s invoice.
DS 1.3—Supporting Repaired Ductwork
Ducts shall be supported with durable supports that do not restrict airflow. Wherever possible, ducts shall be supported above the ground. When contact with the ground is unavoidable, closed cell rigid insulation shall be placed under the ducts.
DS 1.4—Materials and Application
Ducts shall be sealed using water-based mastic labeled as meeting UL 181 standards. Boot to floor connections shall be sealed using either mastic or expanding foam. Foil HVAC tape labeled as meeting UL 181 standards may be used only on the air handler access door. Mastic caulking in tubes meeting the UL 181 standard are recommended to seal the air handler when appearance is a consideration.
All accessible components of the supply plenum and all accessible take-offs, including the gores on flexible elbows, shall be sealed with approved materials. Presence of insulation alone shall not be considered a barrier to accessibility.
Mechanical fastening requirements:
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Disconnected, loose-fitting or new metal ducts shall be fastened using at least three sheet metal screws.
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Disconnected, loose-fitting or new flexible ducts shall be fastened using compression straps tightened using a tool designed for that purpose.
When there are large gaps in sheet metal or in duct connections, repairs shall be made using sheet metal, sheet metal screws, and mastic and mesh reinforcing.
DS 1.5—Installation
All materials shall be installed according to manufacturers’ specifications and instructions. Any loose duct tape or other sealants shall be removed prior to duct sealing. Gaps greater than 1/8 inch shall be reinforced using mesh reinforcing tape. Flex duct connections to metal duct and flex duct splices require metal fittings and must be fastened using a compression strap on the inner liner and a compression strap on the outer liner.
DS 1.6—Manufactured Homes
To qualify for an incentive, reduction in duct leakage to outside must be at least 100 CFM at 50 Pascals.
DS 1.7—Site-Built Homes
To qualify for an incentive, reduction in duct leakage to outside must be at least 100 CFM at 50 Pascals.
DU 1.0—Introduction
Supply and return ducts and plenums shall be insulated. Sheet metal ducts and plenums shall be insulated with R-11or greater insulation batts. Flexible duct shall be R-8 or greater. Special attention shall be paid to elbows and termination areas to ensure complete coverage.
DU 1.1—Duct Air Sealing
Before insulating ducts, all ducts must be sealed according to specifications in Section DS.
Exception: If tested duct leakage is less than 0.10 CFM50 per sq. ft. of floor area (as defined by PTCS), ducts may be insulated without further duct sealing. Documentation of PCTS-certified duct test shall be provided to Home Energy Solutions.
DU 1.2—Insulating Ductwork
All ducts in unconditioned areas shall be insulated. Duct insulation installed in basements, garages, storage areas, or other Human Contact Areas, shall be covered to limit occupant exposure to insulation fibers. Covering shall meet applicable fire codes. Do not insulate flex ducts or preformed fiberglass duct board. Insulation shall be secured to ductwork every 12 inches with twine, noncrossive wire or vinyl tape.
DU 1.3—Supporting/Repairing Ducts
Ducts shall be supported with durable supports. Supports shall not restrict airflow through added flex ducts. Whenever possible, ducts shall be supported above the ground. When contact with the ground is unavoidable, rigid insulation shall be placed between the ground and the duct. |
