Rating System

LEED BD+C: New Construction

Rating System Version

v2 - LEED 2.2, v2 - LEED 2.1, v2 - LEED 2.0

Inquiry

California Title-24 requirements indicate that space conditioning controls must be provided to prevent reheating of air that has been mechanically cooled, recooling of air that has been previously heated, or simultaneous heating and cooling. The code specifically exempts zones that have special pressurization relationships or cross contamination control needs. However, the performance methodology defined in the Alternative Calculation Manual does not indicate how systems serving these zones should be treated in a performance energy model. Our project is a hospital where all zones have special pressurization relationships and cross contamination control needs. We are seeking clarification regarding the modeling protocol for the systems serving these zones. PG&E released a document entitled "2003 Savings by Design Healthcare Modeling Procedures" to define a methodology for modeling the baseline hospital HVAC and lighting systems, for cases where the methodology is not explicitly defined within the Title-24 2001 standards. Savings by Design is a California incentive program for energy efficiency offered by the major California utilities statewide, and modeling methodologies applied by the program are recognized by the California Public Utilities Commission as being consistent with Title-24 energy efficiency requirements. The "2003 Savings by Design Healthcare Modeling Procedures" state: If the standard design practice for the type of system being modeled is a constant air volume system, then the baseline will be a CAV system." Can we apply this HVAC modeling protocol defined in these 2003 Savings by Design Healthcare modeling procedures to our project? Also, can we apply the lighting requirements defined in the Savings by Design Healthcare Modeling procedures in spaces that are excluded from the Title-24 lighting power density requirements?