Total leakage shall be less than or equal to 6 cfm (169.9 L/min) per 100 ft2 (9.29 m2) of conditioned floor area when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the roughed in system, including the manufacturer's air handler enclosure. All register boots shall be taped or otherwise sealed during the test. If the air handler is not installed at the time of the test, total leakage shall be less than or equal to 4 cfm (113.3 L/min) per 100 ft2 (9.29 m2) of conditioned floor area.
Exception: Duct tightness test is not required if the air handler and all ducts are located within conditioned space.
The building duct and plenum system shall meet the requirements above as verified using instruments and procedures specified in ANSI/ASHRAE 152 and ASTM E1554 Test Method A. Tests at other test pressures are permitted to be used if they are converted to equivalent leakage at 25 pascals (Pa) of pressure, and such equivalence is demonstrated to the satisfaction of the code enforcement official. The test shall be conducted by a qualified person, who shall demonstrate competence to the satisfaction of the code enforcement official for the conduct of such tests. For the purpose of this section CFM25 shall mean the leakage from all ducts and plenums in cubic feet per minute measured at 25 pascals of pressure in accordance with ANSI/ASHRAE 152 or ASTM E1554. Test results shall be provided to the code enforcement official and shall include:
- Name and place of business of the tester;
- Address of the building which was tested;
- Conditioned floor area of dwelling, calculated in accordance with ANSI Z65, except that conditioned floor area shall include areas where the ceiling height is less than 5 feet (1524 mm);
- Measurement of CFM25; and
- Certification of accuracy of test results and signature of tester.