This CIR is seeking clarification on the scope of Systems Performance Testing required for Commissioning. The project is a 300,000 square foot residential building located in New York City. As part of commissioning, the project intends to commission the HVAC and refrigeration systems, lighting and daylighting controls and domestic hot water systems as per the credit requirements of EA prerequisite 1 and EA credit 3. All major equipment in the building will be commissioned such as boilers, hot water pumps, roof top units (DX), supply and exhaust fans. However, for cooling, the residences use Packaged Terminal Air Conditioners (PTAC). The Project is seeking guidance on the representative sampling of PTAC for the systems performance testing. The project is intending to test 10% (industry standard) of the PTACs in the building for each size (7500 Btu, 9000 Btu, 12000 Btu etc.) subject to a minimum count of 10. For example, if there are 27 units of Type A, and 120 units of Type B and 400 units of Type C, the functional testing will be done for: 10 qty - Type A 12 qty - Type B 40 qty - Type C If failures are found in a group, in addition to the faulty units, an additional sample is tested. Is this approach of a 1 in 10 representative sampling acceptable to USGBC?
Yes, in this specific case, 10% of PTAC systems subject to a minimum count of 10 are acceptable representative sampling for the systems performance testing. However, in a large multi-family residential project, the operation of a PTAC system may be influenced by the location/orientation of the residential unit. Since, it is being proposed that only representative samples would be tested, therefore, the project team should be careful in the selection of the representative samples and provide sufficient documentation when submitting for LEED review.