Coparison of LEED & Bild It Gtreen rating systen for new home construction

1. Architecture 160
Final Research Paper
Bill Durkin
New Construction “Green” rating systems
A comparison of the National Leadership in Energy and Environmental Design
(LEED) system and the California Green Point Rated system
Buildings have a profound impact on our environment, economy, health and productivity.
In the United States (US) alone, the resources used to operate commercial buildings
represents about 30% of total US annual energy requirements, including 60% of domestic
electricity.
The building industry began to incorporate more environmentally oriented building
materials, and employ different practices with significantly less negative impact on the
building site, energy systems and indoor air quality. The first nationwide program, called
Leadership in Energy and Environmental Design (LEED) was founded in 1993 by the US
Green Building Council group. It targeted the top 25% of the nation’s “green” home
builders. The group designed a rating system that enables builders to receive ‘credits’ in
a number of ways for certification [2].
In California, a number of public agencies, building professionals and non-profit firms
organized a state program to promote state initiatives and encourage ‘best’ sustainable
practices. This effort was developed in Alameda County in 2000 with eight major home
production builders collaborating to provide input and direction in the development of
Green Building Guidelines. In 2005, the Guidelines were updated to expand its
applicability throughout California, address changes in state building ordnances (Title 24
measures) and incorporate measures from other residential green building initiatives.
Both LEED and Green Building Guidelines are similar in that both programs [1]
• Require performance across different categories, as verified by a third-party rating
process
• Encourage builders to aim for increasingly higher levels of performance as the
gain experience with green building
• Serve the full range of residential new construction in California
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2. • The certification rating verification process is managed by independent, non-
profit third party agencies. Build It Green manages the Green Point Rated
program, and the Davis Energy Group manages the LEED program in California.
The two rating systems do differ in their scope of certification. LEED has been
developed for more comprehensive programs that include existing buildings, commercial,
schools, hotels and neighborhood development. Build It Green was initially formulated
for new residential home construction, and is developing verification protocols for
remodeling projects, and existing homes. Both LEED and Green Building Guidelines
programs cover multi-family unit projects.
The scope of this report will just review and focus on the verification programs for new,
single family homes by the LEED and Green Building Guidelines agencies. I will
compare specific components of each rating system by using design and construction
phases in the renovation of the Moraga Barn in Moraga. This building was built in 1914,
as a hotel, and has been completely renovated to LEED platinum standards. Although
this building is a commercial building, it falls under the LEED new construction
guideline, due to the extensive renovation efforts, and the need to maintain it as an
historical landmark. I believe that the ‘green’ components used in the restoration can
provide valid examples in this paper, to make comparative arguments about the two
rating systems.
Background (LEED)
In the early 1990’s, an initiative began with the challenge to create a certification system
that would identify and define more efficient building measures. The US Green Building
Council was founded in 1993, and began the first pilot project named Leadership in
Energy and Environmental Design (LEED). The committee membership included
architects, realtors, building owners, attorneys and environmental and industry
representatives. The group wanted to create a national rating system that would
substantially reduce or eliminate negative environmental impacts in building design and
construction, improve existing non-sustainable designs, and improve construction and
operational practices. This initial project scope designated different rating protocols for
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3. new construction, existing homes and commercial interiors. The LEED Rating System
has now been expanded to include the following protocols, which have created a greater
demand for green products and materials.
The LEED rating system covers both residential and institutional (commercial,
Government, public) buildings, where credits are earned for satisfying criterion, designed
to address specific environmental impacts in the design, construction and
operation/maintenance of buildings. Environmentally sound buildings should be
healthful, durable and affordable as well. The New Construction rating system is
organized into five environmental categories;
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4. • Sustainable Sites
• Water Efficiency
• Energy & Atmosphere
• Materials & Resources
• Indoor Environmental Quality
An additional category, Innovation in Design Process, addresses additional building
expertise and design measures not covered under the five stated categories, or enhance an
existing point attainment in the other categories [5].
Buildings that qualify for LEED rating certification must meet all prerequisites and
achieve the minimum number of credits (points) required. Applicants submit their credit
requests during the project design phase in order to expedite building certification, while
other prerequisites can only be documented and submitted at the construction phase.
Applicants must also submit specific documentation that provides verification that each
specification has been completed correctly. The LEED for New Home construction
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5. protocol has different award levels beyond the required certification credits. Levels are
awarded based on the following scale –
Certify 26 – 32 points
Silver 33 – 38 points
Gold 39 – 51 points
Platinum 52 – 69 points
Background (Green Point Rated)
The Green Building Guidelines are administered by the Build It Green Council
organization., which is a professional, membership organization whose mission is to
promote healthy, durable, energy- and resource efficient buildings in California. The
Guidelines were developed for several reasons
• Provide local governments with a educational tool for city staff, builders and
homeowners, for green building construction
• To present a range of categories from which builders can choose when
constructing new homes in California
• To establish a regionally consistent set of guidelines for green building to help
standardize building practices
• To integrate varying residential initiatives in order to achieve greater simplicity
and local applicability
• To offer a set of guidelines developed by an independent, third party source, to
maintain impartiality and standardization [3]
Build It Green is the result of the 2005 merger of the Green Resource Center (est. 1999)
and Bay Area Build It Green (est. 2003.) The merger combined resources of these two
successful organizations and furthers the goal of transforming the California building
industry to embrace green building.
Bay Area Build It Green was formed in 2003 by a number of local and regionally
focused public agencies, building industry professionals, manufactures, and suppliers. Its
activities were focused on increasing the supply of green homes, raising consumer
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6. awareness about the benefits of building green, and providing Bay Area consumers and
residential building industry professionals a trusted source of information.
The Green Resource Center started in 1999 as a joint project of the City of Berkeley,
the Northern California Chapter of Architects, Designers and Planners for Social
Responsibility (ADPSR), and the Sustainable Business Alliance. Initially fueled by the
passion of volunteer efforts, the Green Resource Center emerged as an influential non-
profit organization, operated by full-time staff and an active board of directors. The
Green Resource Center was known as a trusted green building resource and has entrusted
its reputation for quality, unbiased information to Build It Green. [6]
These various agencies provided technical expertise and input in the creation and the
update of these guidelines, the performance benchmarks in GreenPoint Rated were
specifically developed to address climate and market conditions in California. In
addition, several councils, including the Public Agency Council, Non-Profit Network and
suppliers Network provide input for these guidelines. This holistic approach to
homebuilding emphasizes quality construction, energy efficiency, improved interior air
quality and more livable neighborhoods. The guidelines also stress protecting natural
resources surrounding the building sites, so that the built environment can help people,
communities and ecosystems thrive and prosper. And the process for updating the
program over time is controlled by California decision makers and stakeholders, not by
interests outside of the state. The LEED rating system national program is not tailored to
specific regional conditions [6].
New homes also place greater demands on local water and energy supply and distribution
systems, municipal infrastructures, roadways and transportation systems, and adjacent
communities, both natural and man made. The Green Rated Program strives to reduce
the impacts in these areas. The key to a successfully green built home is the careful
synergy of designing and coordinating of these various measures. This whole house
systems approach requires taking into account the interaction of many factors; heating,
cooling needs, water use, electrical use, renewable energy systems, climate factor as,
topography, and the overall well being of the home occupants. According to the Build
America program, a whole house system approach can reduce the energy consumption of
a new home by as much as 40%, with little or no effect in the cost of construction.
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7. Build It Green wanted to create a more ‘accessible’ rating system to Bay Area builders
than the emerging LEED standard, and combine the efforts of the various organizations
that were initiating green building practices, and build an ‘easier’ rating system and
process. LEED accreditation involves more costs, and process to file for credit on their
various components.
Green Building Guidelines Checklist
The Green Point Rated (GPR) Checklist point matrix has 14 sections, and within each
sub component, one can earn credits in one or more environmental ‘categories’. Each
category has a total potential credit total and a required minimum number of points. A
new building is considered ‘Green’ by Built It Green standards if it earns at least 50
points and meets the minimum points per category
Category Total Points Minimum
Community 24 NA
Energy 108 30
Indoor Air Quality (IAQ)/Health 45 5
Resources 66 6
Water 47 9
Some initiatives sub-sections have potential points in two of these categories. Installing
an energy efficient clothes washing machine, f or example, can earn credits in both the
Energy and in Water categories (total 3 point). Like the LEED rating system, additional
points are available in Innovative Design (total 20 points)
Certification Examples
The Canyon Construction building, located in Moraga, and referred to my many as the
‘Moraga Barn’, will be used for design & construction examples in this certification
example section. The building was built in 1914, and renovated in 2006, with two design
missions; to retain its historical structure, and to renovate it with a LEED platinum rating,
as a working example of the high quality, working, ‘green’ construction designed and
built by their company. The building is submitting 54 credits for the platinum rating. I
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8. will use a few examples of this restoration/greening project to compare how each rating
system assesses the project component.
There are several assumptions to be made in the comparison of the two rating systems.
LEEDS accreditation requires 26 points out of a possible 69 possible points, while the
Green Point Rated system accreditation requires 50 points out a possible 300 points.
While clearly the rating metric points are not immediately comparable, we can make the
assumption that LEED accreditation requires 37% of possible points; the GPR system
requires 16% of possible points. To simplify the comparison process, I assume that each
LEED credit is calculated as roughly twice the value of the GPR credit (37% to 16%)
I will use four examples to illustrate how each rating system evaluates the
design/construction components for the Canyon Construction project
Insulation
The Moraga Barn employed two types of insulation in the remodel. Cellulose
insulation is a fiber material that's sprayed into a wall's cavity during construction.
This material yields higher thermal ratings due to the manner in which it fills
voids and seals out airy drafts. Not only is cellulose healthy for a home, the
natural chemical composition can also hinder insect infestation and is fire and
mold resistant. Spray foam insulation was employed in the roof f the building to
mitigate any condensation issues. The solid foam provides a barrier that
eliminates any dew point issues (with a 5 ‘’ thickness, minimum).
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9. 3.3 inch blown cellulose with 3 inch spray insulation foam in walls (R value 27)
5.5 inch spray insulation foam in roof (R-value 35)
LEED, section – Energy & Atmosphere, Credit 2.2 – Insulation
Insulation is subject to third party inspection for credit (1 point) and must meet
Hone energy Rating system (HERS) Grade II pre-requisites, and gains credit for
HERS Grade I level insulation (1 point)
The Green Point Rated system, section F – Insulation, items 1, 2 and 3
:Insulate with 75% recycled content (1 point each for floor/walls and ceilings)
:Insulation that is low emitting [low Volatile Organic Compounds] (1 point each
for
floor/walls and ceilings)
: Inspection before drywall installation (1 point)
Analysis
Both rating systems require independent, third party verification, and reference
specific standards for point accreditation. I found it very confusing to try to
compare the two requirements, and obtain information on HERS grades.
HVAC radiant flooring
The Moraga Barn implemented a geothermal system for heating and cooling the
interior of the building. The first floor had recycled granite tiles, and the second
and third floors have a High Fly Ash Concrete (HVAC) slab. HFAC utilizes 50%
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10. fly ash, to offset the cement component, thereby reducing the amount of carbon
dioxide emissions by half, in the manufacturing of this material. Pex tubing is
installed in the slab to create a thermal mass within the building to stabilize
heating and cooling loads. Backup systems include a 12 ton chiller and a 92%
efficient gas boiler, both of which exceed LEED efficient rating requirements.
PEX tubing and floor insulation
LEED, section – Indoor Air Quality, Section 6.1 Supply Air distribution
& Section 7 Supply Air Filtering
Ductless air conditioning systems like radiant floor heating (and cooling) are an
alternative to these requirements. Radiant heating and cooling systems (within a
concrete slab) are more efficient, create less dust and create no circulation noise.
The Green Point Rated system, section H – Heating, Ventilation & Air
Conditioning, item 3
This requirement calls for a zoned system, installed with Slab insulation. (One
point is awarded in the Energy category, and one point in the Indoor Air Quality
category
Analysis
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11. Again, it was quite difficult to research the requirements for LEED credit. Their
rating system clearly addresses air duct systems, and it addresses ductless system
in several different sections. GRP awarded 2 points for hydronic systems; one
point for indoor air quality improvement and one point for energy savings, for
amore efficient HVAC system.
Renewable Energy systems (Photovoltaic System design and installation)
The Canyon Barn roof is a pyramidal hip roof. The Atlantis Sun Slate integrated
building panels were installed on all triangular faces of the roof, with four
separate inverters for each face. Any excess electrical power generated during the
day by the 4.4 KW system is returned to the PG&E electrical grid for ‘credit’
Sun Slate tiles being installed
LEED, section – Energy & atmosphere, Credit 2 – On Site Renewable energy
The determination for this credit under LEED is quite complex, for the average
builder/homeowner, for it requires several energy cost calculations, based on
different governmental databases. Based on these prior calculations, the points are
then awarded based on the following percentages of the summary of renewable
energy provided
% Renewable Energy Points
2.5% 1
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12. 7.5% 2
12.5% 3
The Green Point Rated system, section I – Renewable Energy, item 4
Provides successive points (in six point intervals) for the percentage of electrical
needs provided by this renewable energy system
a. 30 % pf electric needs OR 1.2 KW system (total 6 points)
b. 60% pf electric needs OR 2.4 KW system (total 12 points)
c. 90% pf electric needs OR 3.6 KW system (total 18 points)
Analysis
Given the weighing factor (6 vs. 18 points), the GPR point credit clearly awards
more accreditation points for PV systems, in this case. The main reason being for
the scaled weighing in that, electrical power in California, per KW is the forth
highest in the nation, and the cost savings factor per KW is reflected in the higher
California rating system credit. Secondly, California receives more annual
Isolation [4] (the average daily solar amount of radiation received in an area) than
more states, and renewable systems like PV systems can provide more renewable
electrical environmental ‘credits’.
California PV energy cost savings are somewhat difficult to determine, given the
variable costs of PV panels (prices are decling based on current availability) , the
state rebate sliding scale, per watt (decling as more PV systems come online), and
the new federal tax credit (30% of project costs). The LEED system does not
include any of these varying factors in determining the cost/benefit analysis, while
the GPR system ignores these important factors in determining the true life ‘cycle
cost ‘of such a system.
Rainwater Harvesting (Water Catchment systems)
The Canyon building rainwater catchment system collects rainwater from the
2,000 sq. ft. pyramidal hip roof . Rain calculations showed that annual rainfall for
the area is 26” per year, with the roof collecting about 625 gallons in a 1’ rainfall.
The rainwater catchment system was designed to hold 15,000 gallons. The annual
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13. rainfall catchment required for LEED credit is 90% or 14,625 gallons of annual
rainfall. Any excess rainwater not stored on site need to be filtered to attain an
80% sediment free discharge.
15,000 gall water catchment storage tanks
LEED, section SS 6.2 – Storm water Design: Quality Control
: Storm water storage has the capacity to capture 90% of the annual rainfall
Amount
: Any excess water runoff must have 80% of suspended solids removed
The Green Point Rated system
No stated criteria
Analysis
Any accreditation system should evaluate catchments systems with respect to
such examples as
• Mitigate property soil runoff, eliminating soil erosion
• Mitigate excess water runoff on established rainwater runoff systems
• Purify rainwater contaminants through soil filtration
• Recycle water for landscape requirements
• Maintain independent fire protection water reservoirs
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14. • Build indent communities where resources are provided in part by localize
d resource systems
The LEED system provides clear, but detailed guidelines for stormwater catchment
credit, but the GPR system does not adequately addresses this water conservation
measure. This may be addressed in the next version, since California is taking more
drastic measures to conserve water, in light of climate change factors effecting
rainfall and snow fall in our state. The Green Building Guidelines manual mentions
construction of a rainwater catchment system such as a cistern, in the Landscaping
section overview, but there are no points categories for controlling rainwater runoff,
or rainwater harvesting in the Checklist.
Costs of Accreditation
Costs associated with comparing the cost structure for the two rating systems is out side
the scope of this paper, primarily because of the complexity of the LEED requirements
for determining critical energy savings calculations, and the need for detailed drawings,
documents and other filings that would generate another topic. The LEED certification
can be in excess of $20,000, given the project scope. Build It Green costs can be below
$2,500 for minimal accreditation. This is of course, a very important element in
addressing which rating system to choose (in California) for new construction. The cost
for the platinum rating for the Canyon building was $16,000
Other Rating Systems
Green Point Rated is a comprehensive program specifically addressing the needs of
California's residential building industry, but using it does not preclude participating in
other green home rating systems. In fact, Green Point Rated was designed not to compete
with but rather be compatible with programs such as those listed below. The LEED
rating system includes some reciprocation accreditation in some rating programs,
provided certain point totals are attained.
National Association of Home Builders
NAHB is a national, Washington, D.C.-based trade association whose mission is
to enhance the climate for housing and the building industry. Chief among
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15. NAHB’s goals is providing and expanding opportunities for all consumers to have
safe, decent and affordable housing.[7]
California Green Builder
The program encourages voluntary partnerships between builders and local
governments to build cost-effective, green homes that benefit homebuyers and the
community at large. Builders who embrace CGB differentiate themselves in the
marketplace through resource efficiency. Documented savings is a plus for local
officials who must record greenhouse gas emissions and water conservation
efforts. The California Green Builder homebuyers benefit from lower energy
costs while their home makes less impact on the environment. This program was
developed by the building industry for production home builders. This
certification system does not cover the Renewable energy, Community or
Landscaping categories of LEED and Build It Green.[8]
Energy Star
ENERGY STAR is a joint national program of the U.S. Environmental Protection
Agency and the U.S. Department of Energy helping all homeowners save money
and protect the environment through energy efficient products and practices.
Third party raters verify that homes adhere to their standards for insulation,
efficient windows, building envelop, HVAC and home appliances. To earn the
Energy Star Rating, a home must meet guidelines for energy efficiency set by the
U.S. Environmental Protection Agency. These homes are at least 15% more
energy efficient than homes built to the 2004 International Residential Code, and
include additional energy-saving features that typically make them 20–30% more
efficient than standard homes [9]. Both rating systems analyzed promote Energy
Star Lighting and Appliance products in their accreditation protocol [9].
Conclusion
There are many other, possibly more important aspects that will evolve from both green
building initiatives, such as LEED and GPR, which promote sustainable and earth
friendly housing. Hopefully, these measures will help us restructure our ‘world view’
about our buildings, and help us to become better stewards of our environment. They
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16. will help view our buildings as part of the world landscape, rather than abstract structures
of our rational mind. They will help us to use fewer resources in building them, and to
design them so their components can be reused, or recycled. I present several concepts
that may help the reader to better understand how green buildings can gain a wider
acceptance, by the nature of their contribution tour long term lifestyle, and build better
evaluation for us all
Life cycle cost models
Traditionally, financial models for new home construction concentrate on the project
budget, assigning separate dollars to various design and construction phases. When
heating systems are evaluated, for example, the initial purchase/installation costs are too
often used as the deciding choice factor. Green Building concepts help to promote a
better financial model, by evaluating a home’s overall life cycle cost. This long term
view allows the costs of home ownership to be understood from a wider picture, which
includes the initial purchase/installation costs, but maintenance, energy costs, and the
escalating utility factors in the future. Many project decisions are determined by payback
models or risk/benefit analysis, but we seldom apply these models to our new home
analysis. For example, solar thermal hot water systems can provide a payback period of
5-7 years for an average home, given the current state rebates tax credit incentives, and
factored gas price escalation, but new home designers/buyers just view the initial
purchase costs, of a traditional gas fired, hot water system as a ‘cost savings’. A long
term life cycle model will reveal the true savings, and cleaner environmental aspect of
such a solar thermal systems
Conserve natural resources/ Reduce GHG emissions
Such programs significantly offset demands for water, energy, land use and related
infrastructure systems, required for home projects that do not look at their impact on
existing systems. But more important are the reused, and recycled materials that do not
end up in city landfills, retain existing resources like wood and water. Green House
Gases can be reduced with less new materials manufactured, when recycling is employed.
Many materials today are formaldehyde free, or contain very low volatile compounds,
make the environment cleaner, and create better indoor air quality.
Higher cost for going green myth
16

17. A major issue concerning the acceptance of sustainable homes had been the perceived
‘cost’ of going ‘green’. This perception revolves mainly around the costs of sustainable
materials, which includes a variety of factors that confuse the comparison – recycled,
reuse, composite, high efficiency, high tech, etc. This argument may have been more
valid several years ago, but the pricing differential for traditional versus green products
has continued to level out. There several studies that demonstrate that the increased ‘cost’
for new ‘green’ homes lie in the increased design costs. This cost should diminish, as
this is an important tenet of both rating parties’ mission statements – to educate more
manufacturers, architects and builders to green building products and construction
practices. A recent panel discussion of building officials for the cities of Walnut Creek,
Pleasanton, Pleasant Hill and Dublin hosted by the Northern California group for the
USGBC stated that the upfront design costs average about 2-3% for new Homes (March
25, 2009 meeting in the Walnut Creek Lesher Center). This study does not even factor in
the overall savings, when the new home project costs are considered in the total project
life cycle model.
Dual Certification
“The thing I like about standards is that there are so many to choose from….” It’s a
popular lament, especially among architects and builders, and recently with ‘standards’
raters/reviewers of our comparative systems. Given the wide dispersion with the LEED
and GPR accreditation system scales, it is often hard to make comparisons, and to find
common ground so that green components can be compared. The LEED system does
award reciprocal points in the Green Rated program, if applicants achieve certain point
levels in the LEED system
Evolving set of guidelines
These ratings are at best, the best approximation of how builders, architects and vendors
can bring to the marketplace their best evaluations of the most current design, materials
and building practices available. Build It Green has revised, and published their April
2009 guidelines, which were not available for this report, but I am confident will contain
more updated requirements, especially in light of the various new state initiatives. The
LEED program is about to start training on the 3.0 version, as well
Building Industry Changes
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18. Builder will continue to incorporate more sustainable materials in their projects, as the
standards become more commonplace. This will help to encourage more manufacturers
to enter this market, and encourage people to create new sustainable products, especially
as the builders find that their costs to traditional building materials are comparable over
time.
Last words
Learning about the Canyon Construction building has been an invaluable opportunity to
really study all about the ways buildings can reduce their environmental impact. I am also
now learning how buildings can not only minimize their site impact, but contribute to it,
and help rebuild it…
Also, LEED is a federal program; Build It Green is a California based initiative. I now
better appreciate how easier it is to work with a state program. LEED is almost beyond
comprehension, at times, with it s calculations, references to other standards requirements
and verification documentation, to name a few……………...
I hope to learn more……………
Thank you for a most rewarding class……
References
1. Davis Energy Group, Green Point Rated and LEED for Homes
2. LEED, New construction Reference Guide, Version 2.2, Third edition, October 2007
3. Build It Green – Green Building Guidelines, 2007 Edition
4. Grid-Tied PV System Seminar Textbook, Solar Living Institute 2007, pg89
5. http://search.msn.com/results.aspx?q=us+green+building+council&FORM=MSNH11
6. http://www.builditgreen.org/history
7. http://www.nahb.org/page.aspx/generic/sectionID=89
8. http://www.cagreenbuilder.org/
9. http://www.energystar.gov/index.cfm?c=behind_the_walls.btw_landing
ATTACHMENTS
LEED for Homes Pilot Project Checklist
Single Family GreenPoint Checklist
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