Duct and Envelope Tightness (DET) Verifier and Testing
On January 1, 2011, the 2009 International Energy Conservation Code (IECC) with 2011 Georgia State Supplements and Amendments became mandatory and applicable statewide as the new Georgia State Minimum Standard Energy Code. The 2011 GA supplements and amendments include a new definition for Certified Duct and Envelope Tightness (DET) Verifier along with new mandatory testing requirements for verification of the building thermal envelope and duct tightness for new residential construction. Residential buildings include one and two family dwellings (R-3), multi-family apartment buildings (R-2) and residential care/assistance living facilities (R-4) that are three stories or less in height above grade.
The maximum allowable leakage rates for the building envelope and for duct systems that run external to the building envelope are outlined below.
- The building envelope must achieve less than 7 air changes per hour at 50 Pascals (7 ACH50).
- Duct systems can be tested either at rough in or post-construction with the total leakage test OR at post-construction with the leakage to the outside test.
- Rough-In Total (RIT) Leakage must be less than or equal to 6 CFM25 per 100 square feet of conditioned floor area served by that particular duct system.
- Post-Construction Total (PCT) Leakage must be less than or equal to 12 CFM25 per 100 square feet of conditioned floor area served by that particular duct system.
- Post-Construction Leakage to Outside (PCO) must be less than or equal to 8 CFM25 per 100 square feet of conditioned floor area served by that particular duct system.
Testing for building envelope and duct tightness shall be conducted by a certified DET verifier. A certified DET verifier shall be a certified Home Energy Rating Systems (HERS) rater, or be a certified Home Performance with ENERGY STAR contractor, or be a Building Performance Institute (BPI) analyst, or successfully complete a certified DET verifier course that is approved by the Georgia Department of Community Affairs (DCA). See DCA resource list below to find a certified DET Verifier in your area.
The required envelope and duct tightness testing is accomplished by using a blower door and duct blaster (air duct blower) pressure testing system. The results of duct tightness and envelope tightness test are required to be listed by the DET Verifier on a permanent certificate that is posted on or near the electrical panel or air handler. A sample certificate is provided in Appendix D of the Georgia Supplements and Amendments or a fillable format pdf copy of the sample certificate is also available.
Refer to the 2011 GA State Supplements and Amendments for the complete code requirements for Duct and Envelope Tightness (DET) Verifier and Testing. Additional helpful information about how to properly air seal the building envelope and air duct systems is found in Appendix A of the GA amendments and is also available from Southface Energy Institute or US Department of Energy at www.energycodes.gov.
Important Note: Although the new Georgia State Energy Code was implemented as of January 1, 2011, the DET verification testing has been delayed for 6 months per thewaiver issued by the Georgia Department of Community Affairs (DCA). The DET verfication testing will become mandatory and applicable statewide for all new residential buildings that are permitted on or after July 1, 2011.
The following information is provided to help locate certified Duct and Envelope Tightness (DET) verifiers which can perform the duct envelope and tightness testing (blower door and duct blaster test).