Get Ky Residential Energy Code Duct Testing Results 2015-2025

When low-pressure VAV and CAV systems are used, the total allowable leakage should not exceed 2 percent, including the box and downstream ductwork. The box and downstream ductwork should be tested at the lower 1-inch wg static. This is the minimum for most systems currently used in today's design practices.

When low-pressure VAV and CAV systems are used, the total allowable leakage should not exceed 2 percent, including the box and downstream ductwork. The box and downstream ductwork should be tested at the lower 1-inch wg static. This is the minimum for most systems currently used in today's design practices.

There are two standards allowed for duct tightness testing, ANSI/RESNET/ICC 380 (which also includes the blower door testing standards) and the ASTM E1554. Both standards require testing to be performed at a pressure of 25 Pascals or 0.1 inches of water column.

For the post-construction test, leakage measurement must be made across the entire system, including the manufacturer's air handler enclosure, with all register boots taped or sealed at a test pressure of 0.1 inches w.g. (25 Pa).

The test is designed to measure the CFM25 value for leakage in the duct system to outside of the conditioned space. Standard: The measured duct leakage must not exceed 0.04 CFM25 x floor area (in square feet) served by the system.

Percentage of System Volume Flow A percentage of volume flow is also a simple calculation for the testing contractor. For example, suppose you have a duct system where the duct system is handling 14,000 cfm. If the allowable leakage is specified as 2%, then the allowable leakage is 0.02 x 14,000, or 280 cfm.

A duct leakage test can be performed by either pressurizing or depressurizing the ductwork. Ductwork that is outside the building envelope, such as in an unconditioned attic or crawlspace, should be pressurized so as to not bring in unwanted contaminants such as dust.

The 2021 IECC limits both the rough-in and post-construction tests to an air leakage rate of 4.0 cubic feet per minute (CFM) per 100 sq. ft. of conditioned floor area when the air handler is present. If the air handler is not present during the rough-in test, air leakage is limited to 3.0 CFM per 100 sq.