Rating System

LEED BD+C: New Construction, LEED BD+C: Schools, LEED ID+C: Commercial Interiors, LEED BD+C: Core and Shell, LEED O+M: Existing Buildings

Rating System Version

v2 - LEED 2.2, v2 - Schools 2007, v2 - LEED 2.0, v2 - LEED 2.0, v3 - LEED 2008

Inquiry

Background 1: We are designing a mixed use hotel / apartment building in the Philadelphia area. We are investigating the ventilation strategy required to comply with LEED EQ p1 for the living areas in hotel / apartment units. We understand that the IMC 2003 is the applicable mechanical code. We are proposing the following ventilation strategy: natural ventilation through operable windows for hotel / apartment living areas and bedrooms with recirculating systems (PTAC units) for space conditioning; mechanical ventilation via exhaust fans and transfer air for bathrooms and kitchens in hotel / apartment units (see question 2); and central mechanical ventilating units serving corridor / core areas. Question 1: Under this strategy we believe that the living areas and bedrooms would qualify as "natural ventilation" not "mixed mode ventilation" since the PTAC units are recirculating only and do not draw any outside air. Both the International Mechanical Code and ASHRAE 61.1-2004 allow recirculation-only mechanical systems to be installed in spaces where ventilation is provided by natural means. Since the living areas will comply with the natural ventilation requirements, they would not require the mechanical introduction of outside air as is necessary for "mixed mode ventilation." The corridor / core areas would be classified as "mechanically ventilated." We would like verification that including PTAC units in a space with operable windows does not change its classification from "naturally ventilated" to "mixed mode." Background 2: ASHRAE 62.1-2004, Appendix E, indicates that ventilation in residential living areas "is normally satisfied by infiltration and natural ventilation." It also indicates that "the air exhausted from kitchens, baths, and toilet rooms may utilize air supplied through adjacent living areas to compensate for the air exhausted." Section 6.2.8 indicates that "exhaust makeup air may be any combination of supply air, recirculated air, or transfer air." Question 2: We are proposing that the makeup air for kitchen and bathroom exhaust be drawn from corridor ventilation by undercutting the doors to hotel / apartment units. The air would be transferred from the corridor through the living areas to the toilet and kitchen areas. In this scenario, we believe the living / bedroom areas would comply with natural ventilation requirements and be considered "naturally ventilated" while the corridors / kitchens / bathrooms would comply with mechanical ventilation requirements and be considered "mechanically ventilated." We wouldn\'t have any spaces that are considered "mixed mode ventilation." Is this classification accurate based on LEED guidelines? We would like verification that transferring air through a space with operable windows does not change its classification from "naturally ventilated" to "mixed mode." Background 3: ASHRAE 62.1-2004, Appendix E, indicates that ventilation in residential living areas "is normally satisfied by infiltration and natural ventilation." It also indicates that "the air exhausted from kitchens, baths, and toilet rooms may utilize air supplied through adjacent living areas to compensate for the air exhausted." Section 6.2.8 indicates that "exhaust makeup air may be any combination of outdoor air, recirculated air, or transfer air." Question 3: It appears that the applicable code (IMC 2003) and ASHRAE 62.1-2004 Appendix E and section 6.2.8 allow makeup air for toilet and kitchen exhaust to come from infiltration ("outdoor air"). Is this acceptable under LEED EQ p1?