BASC Search | Building America Solution Center

Right – The termination of this kitchen exhaust duct is sealed to the wall to keep out air and water and is screened to keep out pests.

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Wrong – Air sealing and fastening of this duct take-off has been damaged during construction, causing a large gap in the right-hand side of the connection that will reduce air delivered to living spaces and make it difficult to balance the system

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Wrong - The IRC prohibits the use of flex duct for kitchen exhaust and only permits PVC duct for downdraft systems that meet specific exceptions; also, gaps at the ceiling have not been air sealed.

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Wrong – This duct boot is not sealed to the wall board

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Wrong – The plastic seal of the open end of this duct is ripped; the test measurement will overestimate the duct leakage if the temporary seals are not very carefully completed

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Right – These duct take-offs are well sealed to the branch duct

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Wrong – This ductwork is not sealed where the round duct is attached to the square duct riser

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Right – This register is sealed for a final test and the duct test pressure is being monitored at the register

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This constant airflow regulator (CAR) has been fouled by deposition of aerosolized sealant because it was not protected during duct sealing

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Wrong – This duct boot is sealed inside the boot for a duct leakage test; this fails to account for the ductwork leakage between the duct boot and the wall board

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This constant airflow regulator (CAR) has been fouled by aerosolized sealant because it was not covered while the ducts were being sealed with the aerosolized acrylic sealant.

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This exhaust fan duct opens into the attic rather than exiting through the roof and mold has begun to form on the underside of the deck sheathing and on the rafter due to the moist air exiting the duct

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ANSI/RESNET/ICC 380: Standard for Testing Airtightness of Building, Dwelling Unit, and Sleeping Unit Enclosures; Airtightness of Heating and Cooling Air Distribution Systems; and Airflow of Mechanical Ventilation Systems

Reference

This ANSI/RESNET/ICC standard provides a consistent, uniform methodology for evaluating the airtightness of building, dwelling unit, and sleeping unit enclosures and heating and cooling air distribution systems, and the air flows of mechanical ventilation systems.

Exhaust fan ducts should be made of rigid metal ducting not flexible corrugated ducts like these and the ducts should be attached to the roof or soffit to vent completely to the outside not left open in the attic near an attic vent

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Kitchen Exhaust Retrofit Duct Guide

Guide

Guide describing the retrofit of kitchen exhaust systems, including duct sizing and routing considerations.

Existing HVAC System Upgrade or Expansion

Guide

Guide describing how to upgrade or expand an existing HVAC system.

Duct Leakage Testing for Central Exhaust and Ventilation Systems in Multifamily Buildings

Guide

Guide describing the testing of duct leakage in central ventilation systems for multi-story, multi-family buildings.