A certified DET verifier shall be a certified Home Energy Rating Systems (HERS) rater or a certified Home Performance with ENERGY STAR contractor or a Building Performance Institute (BPI) Analyst, or successfully complete a certified DET verifier course that is approved by the Georgia DCA. Green Summit employs 4 BPI Analysts and 1 HERS rater.
3. Does the DET verifier need to be a third party?
No. DET verifiers do not have to be third party. Language concerning third party inspectors in Appendix C of Georgia’s Supplements and Amendments is intended to be adopted by a jurisdiction should it desire a third party to perform inspections for the energy code as a whole and not Duct and Envelope Tightness verification.
4. What are the tightness requirements set by the DET verification diagnostic testing?
The maximum allowable leakage for the building envelope and duct systems external to the building envelope are outlined below.
Building Envelope must achieve <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.
Existing duct systems must be tested and proven tight to the same criteria as new systems if more than 50% of an existing duct system has been modified or altered. Except for longitudinal seams, mastic or mastic tape is required as a sealant for any new or modified ductwork.
5. When does a duct system need to be tested?
A newly installed duct system must be tested if any part of the duct system or air handler is located outside the building envelope, i.e. in unconditioned space. The test may be performed at rough-in or at final (see question 4 above).
When just the equipment (air handler, furnace, air conditioner coil, etc.) is replaced, the duct system is not required to be tested. However, mastic is required to be applied to all plenum connections including air handler holes and seams, as well as plenum to air handler and plenum to collar connections. Additional sealing with mastic beyond the plenum connections is optional.
6. When does a house need to be tested?
Houses must be tested for building envelope tightness if they are new homes or if they are existing homes that have undergone a renovation that affects the entire building envelope (e.g., gut rehabs).
7. What are the testing requirements for low-rise multi-family building (R-2)?
Low-rise multifamily buildings (3 stories or less) fall under the residential code. Duct tightness testing must be conducted for these buildings. However, a builder may either have the building tested for envelope tightness or have the units in the building undergo a visual inspection by a third-party.
The visual inspection requires that a third party inspect each dwelling unit at least two times during construction for the items listed in table 402.4.2 of the energy code and illustrated in Appendix A of Georgia’s Supplements and Amendments. If blower door testing multifamily units for envelope tightness, a builder may either sample one in four dwelling units on each floor or follow the sampling protocol described in Chapter 6 of the 2006 Mortgage Industry National Home Energy Rating Systems Standards.
8. Do additions need to be tested with a blower door for building envelope tightness?
No, neither additions nor the houses to which they are attached are required to be tested UNLESS the construction affects the entirety of the building envelope (see question 6).
9. How much does DET verification cost?
Price is based on size of the home and number of HVAC systems to be tested. Contact us for a firm quote.
10. What are the steps to verify the duct and envelope tightness of a home?
A certified DET verifier must first perform the blower door and duct pressurization diagnostics using the protocol detailed in Appendix B of Georgia’s Supplements and Amendments. The results of these tests along with the DET verifier’s name and contact information must then be posted on the compliance certificate for the code official to view
11. Where do the DET verification results need to be posted?
The results of the DET verification should be included on the compliance certificate to be posted on or near the electrical distribution panel or air handler.
12. What happens if a house or duct system fails the DET verification tests?
The builder must identify and target leakage through air sealing and duct sealing measures and retest the building and any non-compliant duct system until the failed test is passed. See Appendix A of the Georgia Amendments for detailed information on air sealing practices. Proper assembly and proper application of mastic on joints and seams of mechanical duct systems should yield passing results.