Our project is a residential dormitory on a university campus. We request clarification regarding EQ credit 3.1. The project is registered under LEED NC version 2.1. The LEED NC v2.1 Reference Guide states that all return air grilles must have MERV 8 filters installed during construction. Our project does not have return air ducts as the air handling units (AHUs) provide 100% outside air to the corridors. There are dedicated bathroom exhaust units that negatively pressurize the dorm rooms, but this air is not recirculated. To comply with this credit, must we filter exhaust air with MERV 8 filters? We intend for these openings to be covered during construction, but we ask specifically for the times at the end of the project when we are balancing and commissioning the systems. We assume that these exhaust grills will not need to be filtered at any time. We have a similar clarification request concerning our fan coil units (FCUs) providing heating and cooling in the dormitory units. These units take air from within the room they are located, heat or cool it, and then recirculate it through the room. We plan to keep these units completely protected until after all work is substantially complete, all dust-generating activities are finished, and the rooms are cleaned. Our questions relate to what has to happen with these units during balancing, commissioning and prior to occupancy. The CIR Ruling dated 10/20/03 indicates that regardless of HVAC protection, "new MERV 13 filtration media must be installed at Air Handlers immediately prior to occupancy," which we plan to do for all AHUs. If our FCUs are protected during construction, we follow our IAQ Management Plan, and rooms are cleaned before balancing and commissioning, are there any filtration requirements during system balancing and commissioning or prior to occupancy? It is our understanding that the MERV 13 requirement would only apply to the AHUs. Could you please confirm our assumptions concerning the exhaust grills and FCUs?
Based on the description given, there are two distinctive inquiries in this credit interpretation request. In response to the first question, the intent of MERV 8 filtration in return air grilles is to protect all spaces from cross contamination due to construction activities. As long as the exhaust system described is independent and there is no capability for cross contamination with other spaces, then installing MERV 8 filters would not be required. As for the filtration requirements during air balancing and commissioning phase, MERV 13 filters are not required in the system if the filters do not meet the project\'s design and performance requirements. However, this will require that the commissioning and balance testing procedures need to be coordinated when no indoor construction activities have taken place that could adversely affect the indoor air quality. Lastly, to be consistent with previous rulings (EQc3.1 CIRs ruling dated 12/24/2004 and 10/20/2003), the fan coil units would need to have MERV 13 filtration media installed during construction and prior to occupancy. -- *NOTE (Nov 1 2007): Per errata posted in Fall 2007, there is no LEED or ASHRAE 52.2-1999 requirement for MERV 13 filtration during construction. LEED-NCv2.1 EQc3.1 requires MERV 8 filters on return air grills during construction, and for all filtration media to be replaced with MERV 13 immediately prior to occupancy/at the end of construction. Applicable Internationally.