The purpose of this test procedure is to measure the air leakage rate through a building enclosure or a dwelling unit enclosure.

The measurement procedure shall be based on the specifications of Residential Energy Services Network's (RESNET) 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 (ANSI/RESNET/ICC 380-2019) (RESNET 380) as further specified in Subsections RA3.8.2, RA3.8.3, RA3.8.4 below.

This enclosure leakage procedure is applicable to:

• Single family building enclosures
• Multifamily dwelling unit enclosures

The instrumentation for the enclosure leakage measurements shall conform to the specifications in RESNET 380 Section 4.1.

The enclosure leakage measurement procedure shall conform to the following specifications:

1. The procedure for preparation of the building or dwelling unit for testing shall conform to the applicable requirements in RESNET 380 Section 4.2.
2. The procedure for installation of the test apparatus, and preparations for measurement shall conform to the applicable requirements in RESNET 380 Section 4.3.  If compliance requires the results of the test to be reported in cubic feet per minute per ft2 of dwelling unit enclosure surface area at 50 Pa (0.2 inch water) (CFM50/ft2 of enclosure), the dwelling unit enclosure interior surface area in ft2 (compartmentalization boundary area) shall be recorded. Note: the compartmentalization boundary area is the sum of the interior surface areas of the dwelling unit enclosure walls between dwelling units, exterior walls, ceiling, and floor.
3. The procedure for the conduct of the enclosure leakage test shall conform to the One-Point Airtightness Test specified in RESNET 380 Section 4.4.1.

The results of the test shall be determined as follows:

1. The leakage airflow in CFM50 determined by the One-Point Airtightness Test specified in RESNET 380 Section 4.4.1 shall be adjusted using RESNET 380 Section 4.5.1, equation (5a).
2. If compliance requires the results of the test to be reported in air changes per hour at 50 Pa (0.2 inch water) (ACH50), the leakage results determined by RESNET 380 Section 4.5.1, equation (5a) shall be converted to ACH50 using RESNET 380 Section 4.5.2, equation (7a).
3. If compliance requires the results of the test to be reported in CFM50/ft2 of enclosed the leakage results determined by RESNET 380 Section 4.5.1, equation (5a) shall be converted to CFM50/ft2 of enclosure using RESNET 380 Section 4.5.2, equation 10.

If the applicable value(s) for CFM50, ACH50, or CFM50/ft² of enclosure determined in Section RA3.8.4 are less than or equal to the enclosure leakage compliance criterion specified by the Standards or the Certificate of Compliance, the enclosure complies. Otherwise the enclosure does not comply.