Our LEED-NC v2.2 project includes 5 high rise hotels having an approximate total of 5,000 guest rooms with two-pipe chilled water fan coil units and supplemental electric heating. The windows within the guest rooms are not operable, and mechanical ventilation is ducted directly to each guest room from central air handling systems utilizing 100% outdoor air commercial rooftop units. The amount of outdoor air delivered to each guest room meets or exceeds the requirements of ASHRAE 62.1-2004. All air exhausted from the toilet rooms is ducted directly to the outdoors. The third part of the requirement for EQ 5 requires MERV 13 or better filtration on all building HVAC systems serving regularly occupied spaces. The guest room fan coil units cannot physically handle the MERV 13 filters due to filter size and increased air pressure drop across the filter. The corridor supply units, which are commercial grade, can and will be provided with MERV 13 filters. The project design will also meet both of the other requirements for this credit for the entryway systems and chemical and pollutant exhaust and control. We propose to meet the credit requirements by providing MERV 8 filters on all guest room fan coil units and MERV 13 filters on the commercial rooftops serving the corridors. All outdoor air ventilation is provided through the rooftop units. The fan coils will handle only recirculated air within each guest room. These filtration levels are the best that the systems can accommodate. We feel that this approach meets the intent of the credit while providing a practical and superior approach to hotel applications. Is this approach acceptable?
The filtration portion of NCv2.2 EQc5 requires MERV 13 filters should be applied to process both outside air and return air that is to be delivered as supply air. The recirculated air that you are referencing would be considered return air, and would therefore need to be filtered with MERV 13 filters. The credit states that the design team should "Ensure that air handling units can accommodate required filter sizes and pressure drops". The fan-coil units would be considered to be air handling units as they process air for human use. MERV 13 filters are available in a 2" thick version. Upsizing of fan coil fan motors would allow for the increased pressure drop required for the filter. NOTE: UPDATED CREDIT LANGUAGE FOR 2009 STATES THAT "PARTICLE FILTERS OF AIR CLEANING DEVICES SHALL BE PROVIDED TO CLEAN THE OUTDOOR AIR AT ANY LOCATION PRIOR TO ITS INTRODUCTION TO OCCUPIED SPACES". REQUIREMENT FOR FILTRATION ON RETURN AIR IS NO LONGER APPLICABLE TO ANY RATING SYSTEM. Applicable Internationally.