Page 198 - The Engineering Guide to LEED-New Construction Sustainable Construction for Engineers

176 Cha pte r F o u r

For projects with multiple systems, each individual system does not need to meet the
criteria based on the inequality in Eq. (4.4.5), but the overall project average must meet
the criteria. The LEED-NC 2.2 Reference Guide has a table in the EAc4 section that gives
default maximum allowable equipment refrigerant charges in pounds of refrigerant per
ton of cooling for several refrigerants based on the default losses and leaks and
applicable equipment life. These default maxima are for the individual pieces of
equipment. These default maxima do not have to be met if the overall project complies
with Eq. (4.4.5). There is also technical guidance for adapting this credit to projects with
district energy systems on the USGBC Registered Project Tools page found at http://
www.usgbc.org/projecttools.
It is important that the refrigerant also be chosen based on compliance with the
Montreal Protocol, as many refrigerants are being phased out over the next two decades.
It is recommended that project designers refer to the EPA ozone depletion and global
warming potential lists on its website for information on new or alternative refrigerants.
In addition, in 2004 several major corporations formed an initiative called Refrigerants,
Naturally! The intent of this initiative is to promote and develop refrigeration technologies
which are HFC-free. Its website contains information on many alternative systems, such
as those with carbon dioxide and solar cooling. Tri-State Generation and Transmission
Association, Inc., also has a Web-based Energy Library which gives information on many
alternatives.

Special Circumstances and Exemplary Performance
In summary, two points will be awarded in this category for LEED 2009 (one for
LEED 2.2) if no CFCs, HCFCs, or halons are used for fire suppression systems, and
either the criteria in Eq. (4.4.5) are met or there are no refrigerants used other than
natural refrigerants in the base building HVAC&R systems. There is no EP point
available for this credit.

4.5 EA Credit 5: Measurement and Verification
Designing a system to be more efficient and the system actually performing in that
manner in various situations with different occupancies are two separate issues.
Therefore, credit is also given if it can be proved that the systems are operating as
intended. A side benefit of this credit is that it gives the owners the knowledge of which
systems may not be operating as efficiently as desired and, therefore, the opportunity
for modification and improvement. LEED 2009 awards three points for EAc5, whereas
LEED 2.2 awarded one point.

USGBC Rating System
LEED-NC 2.2 lists the Intent, Requirements, and Potential Technologies and Strategies
for EAc5 as follows, with modifications to incorporate additional LEED 2009 verbiage,
particularly with numbering the credit options and providing a process for corrective
action if appropriate:

Intent
Provide for the ongoing accountability of building energy consumption over time.