Page 170 - The Engineering Guide to LEED-New Construction Sustainable Construction for Engineers

148 Cha pte r F o u r

Option
and Path Guidance Requirements
Option 2 ASHRAE Advanced • Building less than 20,000 sf GFA
Path 1 Energy Design Guide • Office occupancy
for Small Office
Buildings 2004
Option 2 ASHRAE Advanced • Building less than 20,000 sf GFA
Path 2 Energy Design Guide • Retail occupancy
for Small Retail
Buildings 2006
Option 2 ASHRAE Advanced • Building less than 50,000 sf GFA
Path 3 Energy Design Guide • Warehouse or self-storage occupancy
for Small Warehouses
and Self-Storage
Buildings 2008
Option 3 Advance Buildings™ • Building less than 100,000 sf GFA
Core Performance™ • Health care, warehouse, and laboratory facilities are
Guide not eligible
• Office, school, public assembly, and retail projects
comply with
Section 1: Design Process Strategies and
Section 2: Core Performance Requirements
• Other project types comply with the basic requirements
• Additional requirements for EAc1 points are:
The building must have a window-to-wall ratio less
than 0.40
1 point given for compliance with Sections 1 and 2
1 point additional for every 3 strategies
implemented from
Section 3 for a maximum total of 3 points
(strategies 3.1–Cool Roofs, 3.8–Night Venting, and
3.13–Additional Commissioning not included)

TABLE 4.0.3 Summary of Options 2 and 3 in LEED 2009 EAp2: Minimum Energy Performance and
EAc1 Optimize Energy Performance

This prerequisite requires that certain mandatory provisions in the energy standard
be met. In addition, there are other items that may be met by either adhering to some
pres criptive requirements in the standard or alternatively meeting the intent of these
prescriptive requirements by meeting certain overall design-based performance criteria.
Prescriptive requirements in standards generally refer to actions that are specifically met,
whereas, with design-based performance criteria, there may be many design options that
will fulfill a similar goal. For instance, a prescriptive requirement might state that all
windows must be double-paned, whereas a performance requirement might state that
the overall energy loss from the windows must not exceed a certain value.