Since the adoption in 2020, the energy code requirements for South Carolina have been governed by the 2009 IECC. The entire state is in climate zone 3, which dictates some of the the leakage requirements and testing guidelines. The guidelines for South Carolina are as follows:

1. Blower Door Testing: Homes in South Carolina can meet the state energy code requirement via a documented visual inspection checklist or through a performance path by way of a passing blower door test. This test is aimed at measuring the air tightness of the building. The requirement is that the building envelope must not exceed more than 7 air changes per hour at a pressure difference of 50 Pascals (ACH50).
2. Duct Leakage Testing: While there are 2 paths to compliance for the building tightness, South Carolina requires that all HVAC duct systems be tested, if any portion of the system is outside the building envelope. This test is designed to ensure the tightness of the ductwork system. While every system must be tested, there are provisions that allow 3 different methods of testing:

• ‍Post Construction Duct Leakage Testing: The allowable leakage for post-construction testing is up to 12 cubic feet per minute per 100 square feet of conditioned floor area served by the duct system. As noted above, this only applies if any portion of the ductwork is outside the building envelope. If your home has a sealed attic with spray foam or another insulation that is installed in direct contact with the the roof deck, then the duct system may not have to be tested.‍
• Pre Drywall Duct Leakage Testing: South Carolina also offers the option to test duct leakage prior to drywall, however the pass/fail guidelines are more stringent. At this stage, the allowable leakage for testing is up to 6 cubic feet per minute per 100 square feet of conditioned floor area.‍
• Total Leakage to Outside: The last options for duct leakage compliance is to perform a test that includes the use of both a blower door and a duct blaster. In conjunction these tools can be used to measure the total Leakage to the Outside, also known as LTO. The allowable leakage for LTO testing is up to 8 cubic feet per minute per 100 square feet of conditioned floor area.‍

1. Who Can Perform the Tests: The governance of who qualifies to perform energy code testing generally falls to local building inspectors. There are several  certifications available for energy code testing, including those provided by RESNET and the Building Performance Institute (BPI). All field inspectors at Green South Energy Solutions are BPI certified for Infiltration and Duct Leakage (IDL).

It's important for builders and homeowners in South Carolina to consult with local building departments or energy code specialists to confirm the specific requirements and standards applicable in their area. Additionally, hiring qualified professionals to conduct these tests is crucial for accurate and compliant results.

For more detailed and specific information about the code requirements in South Carolina, it would be beneficial to directly consult the 2021 South Carolina Residential Code or reach out to local energy experts or building code officials.