3.1 LEED rating system
3.1. Rejting sustav LEED
The LEED rating system is administered by
United States Green Building Council (USGBC).
LEED is a voluntary rating system to ensure a superior
environmental performance of a building over its life
time. LEED was developed to evaluate the performance
of construction and design from a standpoint of
sustainability in 1998 for commercial constructions.
Since its inception, LEED has evolved and improved
through several revisions. LEED 2009 is the current
version, while discussions are currently underway for
LEED 2012. LEED 2009 contains the following specifi
c rating systems: 1) New Construction (NC); 2) Existing
Buildings: Operations and Maintenance; 3)
Commercial Interiors; 4) Core and Shell; 5) Retail; 6)
Healthcare; 7) Homes; and 8) Neighborhood Development.
Each of the rating systems is composed of 100
points, which are divided among fi ve categories: Sustainable
Sites (26); Water Effi ciency (10); Energy and
Atmosphere (35); Materials and Resources (14); and
Indoor Environmental Quality (15). Additionally, up to
10 bonus points are possible through innovative design
and consideration of regional priorities. Each category
in LEED 2009 has certain prerequisites that are mandatory
for all projects and are not eligible for points. The
points are then distributed across major categories and
are assigned in a progressive way for incremental level
of documented efforts to increase environmental performance.
The LEED system rates buildings at four
levels - certifi ed, silver, gold, and platinum, with the
following credit requirements:
- Certifi ed - 40 - 49 points
- Silver - 50 - 59 points
- Gold - 60 - 79 points
- Platinum - 80 points and above
Currently, the LEED rating system is a nationally
accepted benchmark for design, construction and operation
of high-performance green buildings and is used to
evaluate a signifi cant portion of new construction within
the United States. In the commercial arena in the United
States, LEED is the market leader, with 90 % of all certifi
ed buildings being LEED certifi ed. It can be argued
that the LEED system is also a global leader in green
building. The LEED International Roundtable is composed
of representatives from 21 countries who work to
provide global consistency in regional approaches to
green building. Each of these 21 countries utilizes LEED
rating systems that are catered to the local conditions in
their country. Additionally, LEED has registered projects
in 133 countries. The percentage of new construction
projects evaluated by LEED (for New Construction) has
markedly increased throughout the last decade, as various
stakeholders recognize the need to validate their
achievements for sustainable construction. The green
building concept and sustainable design are growing
phenomenon in engineering, which has an unprecedented
growth rate and acceptability. In 2006, studies showed
that about 20 % of the designers have been involved in
projects that have resulted in LEED certifi cation as opposed
to only 10 % in 2003 (BDC, 2011). It is projected
that by the end of 2013, 94 % of the current architectural
and engineering fi rms would be extensively working on
green projects (Bernstein and Bowerbank, 2008). In the
future, it is speculated that green building rating systems
will move towards performance-based systems and have
a performance monitoring protocol in place. The fact
that the energy supply and resources are diminishing;
coupled with the increased awareness in people to contribute
towards sustainability is helping drive this rapid
growth in green buildings. People like to see their efforts
validated by an agency and USGBC through LEED is
providing that. Furthermore, despite dominance of
Buildings Research Establishment Environmental Assessment
Methodology (BREEAM) in the European
green building performance market, LEED is gaining
some traction. Various projects all over Europe are
adopting LEED measures. Several buildings have been
already LEED certifi ed in Italy, England, Poland, the
Czech Republic, Bulgaria, and Portugal.
3.2 Questionable ratings in LEED
3.2. Dvojbeni rejtinzi u LEED-u
3.2.1 LEED – Materials
3.2.1. LEED – materijali
The USGBC, although a grand and comprehensive
effort towards sustainable design, has certain pitfalls
in terms of how it rates the materials. There are
provisions in LEED and other primary green building
programs, which could result in signifi cant negative impact
on wood and wood products as a building material
(Bowyer, 2008). The LEED rating system rates the material
at the same level while being used in the building.
All materials are considered at an equal footing and their
life history does not have an impact on the rating credits.
Materials like, concrete and wood are considered equal.
However, life cycle analysis have shown that wood has
less embodied energy than concrete or steel because it is
a biological renewable material (Puettman et al., 2005),
while the raw materials to