The LEED 2.0 Reference Guide states, "Underfloor HVAC systems are assumed to have an air change effectiveness greater than 0.9 and do not require testing." This statement is not in the 2.1 Reference Guide. Can we assume that because underfloor systems do have an air change effectiveness greater than 0.9 that we do not have to provide any testing when submitting under LEED 2.1? Please clarify.
No testing is required for this credit if the design path is chosen. Please refer to the EQc2 ruling dated 7/19/04 for a thorough description of the design path and submittals for achieving this point, including how to deal with heating conditions and high cooling loads. Underfloor air distribution (UFAD) systems are somewhat simpler to document for EQc2 than other systems. Since ASHRAE Chapter 32, Table 4 does not include recommendations for underfloor systems, use the manufacturers\' recommendations for proper selection and spacing of the diffusers and then use ASHRAE 62-2001, Appendix N, Table 6.2, to select a zone air distribution effectiveness. Note that zone air distribution effectiveness is equivalent to ASHRAE 129 air change effectiveness (ACE). Per Table 6.2, underfloor systems in the cooling mode have an ACE greater than 0.9. However, not all underfloor system designs will achieve a sufficiently high ACE in the heating mode. For instance, UFADs that heat from the floor (e.g. through grilles along the building perimeter) have an ACE of 0.8 per the ASHRAE table. These systems may not qualify for this credit. Per EQc2 ruling dated 7/19/04, the ACE in each space in both heating and cooling mode must be documented and the average ACE must be shown to exceed 0.9. Applicable internationally.