DRAFT GreenPoint Rated Existing Home Rating Manual version 6.0 | Page 94

J Building Performance and Testing J7. SUPPLY AND RETURN AIR FLOW TESTING CRITERIA FOR QUALIFICATION Two points of credit are available for having an experienced home performance professional test each register and match the results to the design calculations, and taking corrective action to repair any problems and achieve the performance targets. Use a flow hood to test the total supply air flow rates in each room of the home. Adjust the air flow rates using balancing dampers (at plenum) to ensure that supply air flow rates are within +/- 10% of the calculated values from Air Conditioning Contractors of America (ACCA) Manual J and D. The rooms should be balanced based on room size, total supply, and total return. The total supply must be within 10% of the total return. Testing should follow Building Performance Institute (BPI) standard testing practices, or an equivalent recognized methodology. VERIFICATION Documentation: The Rater will collect a report and documentation of test results that are within 10% of ACCA Manual J calculations from a qualified professional, such as a home performance contractor. These tests may be completed by the Rater, if he or she is appropriately qualified. INTENT To increase building comfort and conserve energy used by forced air systems, by verifying performance through testing and adjusting the systems as needed. J8. MECHANICAL VENTILATION TESTING AND LOW LEAKAGE CRITERIA FOR QUALIFICATION One point of credit is available for having a certified HERS Rater test the mechanical ventilation system (each supply and exhaust fan used for ventilation) and then match the results to ASHRAE 62.2-2010. Additionally, the system must be pressurized to verify that the duct system does not leak more than 6%. VERIFICATION Documentation: The Rater will collect the following: ? ? ? The results of the total ventilation flow rates The ASHRAE 62.2 minimum requirements The duct leakage test results from a HERS Rater or another qualified professional INTENT To improve indoor air quality by using mechanical ventilation and verifying performance through testing and adjusting the systems as needed. GreenPoint Rated Existing Home Rating Manual Version 6.0, September 2013 © Build It Green 88