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Buildings account for one-sixth of the world's fresh
water withdrawals, one-quarter of its wood harvest, and two-fifths of
its material and energy flows (Roodman and Lenssen,
1995). Building "green" is an opportunity to
use our resources efficiently while creating healthier buildings that
improve human health, build a better environment, and provide cost
savings.
What
Makes a Building Green?
A green building, also known as a sustainable
building, is a structure that is designed, built, renovated, operated,
or reused in an ecological and resource-efficient manner. Green
buildings are designed to meet certain objectives such as protecting
occupant health; improving employee productivity; using energy, water,
and other resources more efficiently; and reducing the overall impact to
the environment.
What Are the Economic Benefits
of Green Buildings?
A green building may cost more up front, but saves
through lower operating costs over the life of the building. The green
building approach applies a project life cycle cost analysis for
determining the appropriate up-front expenditure. This analytical
method calculates costs over the useful life of the asset.
These and other cost savings can only be fully
realized when they are incorporated at the project's conceptual design
phase with the assistance of an integrated team of professionals. The
integrated systems approach ensures that the building is designed as one
system rather than a collection of stand-alone systems.
Some benefits, such as improving occupant health,
comfort, productivity, reducing pollution and landfill waste are not
easily quantified. Consequently, they are not adequately considered in
cost analysis. For this reason, consider setting aside a small portion
of the building budget to cover differential costs associated with less
tangible green building benefits or to cover the cost of researching and
analyzing green building options.
Even with a tight budget, many green building measures
can be incorporated with minimal or zero increased up-front costs and
they can yield enormous savings
(Environmental Building News, 1999).
What Are the Elements of
Green Buildings?
Below is a sampling of green
building practices.
Siting
- Start by selecting a site well suited to take
advantage of mass transit.
- Protect and retain existing landscaping and
natural features. Select plants that have low water and pesticide
needs, and generate minimum plant trimmings. Use compost and
mulches. This will save water and time.
- Recycled content paving materials, furnishings,
and mulches help close the recycling loop.
Energy Efficiency
Most buildings can reach energy
efficiency levels far beyond California Title 24 standards, yet most
only strive to meet the standard. It is reasonable to strive for 40
percent less energy than Title 24 standards. The following strategies
contribute to this goal.
- Passive design strategies can dramatically affect
building energy performance. These measures include building shape
and orientation, passive solar design, and the use of natural
lighting.
- Develop strategies to provide natural
lighting. Studies have shown that it has a positive impact on
productivity and well being.
- Install high-efficiency lighting systems with
advanced lighting controls. Include motion sensors tied to dimmable
lighting controls. Task lighting reduces general overhead light
levels.
- Use a properly sized and energy-efficient
heat/cooling system in conjunction with a thermally efficient
building shell. Maximize light colors for roofing and wall finish
materials; install high R-value wall and ceiling insulation; and use
minimal glass on east and west exposures.
- Minimize the electric loads from lighting,
equipment, and appliances.
- Consider alternative energy sources such as
photovoltaic and fuel cells that are now available in new products
and applications. Renewable energy sources provide a great symbol of
emerging technologies for the future.
- Computer modeling is an extremely useful tool in
optimizing design of electrical and mechanical systems and the
building shell.
Materials
Efficiency
- Select sustainable construction materials and
products by evaluating several characteristics such as reused and
recycled content, zero or low off gassing of harmful air emissions,
zero or low toxicity, sustainably harvested materials, high
recyclability, durability, longevity, and local production. Such
products promote resource conservation and efficiency. Using
recycled-content products also helps develop markets for recycled
materials that are being diverted from California's landfills, as
mandated by the Integrated Waste Management Act.
- Use dimensional planning and other material
efficiency strategies. These strategies reduce the amount of
building materials needed and cut construction costs. For example,
design rooms on 4-foot multiples to conform to standard-sized
wallboard and plywood sheets.
- Reuse and recycle construction and demolition
materials. For example, using inert demolition materials as a base
course for a parking lot keeps materials out of landfills and costs
less.
- Require plans for managing materials through
deconstruction, demolition, and construction.
- Design with adequate space to facilitate
recycling collection and to incorporate a solid waste management
program that prevents waste generation.
Water Efficiency
- Design for dual plumbing to use recycled water
for toilet flushing or a gray water system that recovers rainwater
or other nonpotable water for site irrigation.
- Minimize wastewater by using ultra low-flush
toilets, low-flow shower heads, and other water conserving fixtures.
- Use recirculating systems for centralized hot
water distribution.
- Install point-of-use hot water heating systems
for more distant locations.
- Use a water budget approach that schedules
irrigation using the California Irrigation Management Information
System data for landscaping.
- Meter the landscape separately from buildings.
Use micro-irrigation (which excludes sprinklers and high-pressure
sprayers) to supply water in nonturf areas.
- Use state-of-the-art irrigation controllers and
self-closing nozzles on hoses.
Occupant
Health and Safety
Recent studies reveal that buildings with good overall
environmental quality can reduce the rate of respiratory disease,
allergy, asthma, sick building symptoms, and enhance worker
performance. The potential financial benefits of improving indoor
environments exceed costs by a factor of 8 and 14
(Fisk and Rosenfeld, 1998).
Choose construction materials and interior finish
products with zero or low emissions to improve indoor air quality. Many
building materials and cleaning/maintenance products emit toxic gases,
such as volatile organic compounds (VOC) and formaldehyde. These gases
can have a detrimental impact on occupants' health and productivity.
Provide adequate ventilation and a high-efficiency,
in-duct filtration system. Heating and cooling systems that ensure
adequate ventilation and proper filtration can have a dramatic and
positive impact on indoor air quality.
Prevent indoor microbial contamination through
selection of materials resistant to microbial growth, provide effective
drainage from the roof and surrounding landscape, install adequate
ventilation in bathrooms, allow proper drainage of air-conditioning
coils, and design other building systems to control humidity.
Building Operation and
Maintenance
Green building measures cannot achieve their goals
unless they work as intended. Building commissioning includes testing
and adjusting the mechanical, electrical, and plumbing systems to ensure
that all equipment meets design criteria. It also includes instructing
the staff on the operation and maintenance of equipment.
Over time, building performance can be assured through
measurement, adjustment, and upgrading. Proper maintenance ensures that
a building continues to perform as designed and commissioned.
Steps
to Ensure Success
- Establish a vision that embraces sustainable
principles and an integrated design approach.
- Develop a clear statement of the project's
vision, goals, design criteria, and priorities.
- Develop a project budget that covers green
building measures. Allocate contingencies for additional research
and analysis of specific options. Seek sponsorship or grant
opportunities.
- Seek advice of a design professional with green
building experience.
- Select a design and construction team that is
committed to the project vision. Modify the RFQ/RFP selection
process to ensure the contractors have appropriate qualifications to
identify, select, and implement an integrated system of green
building measures.
- Develop a project schedule that allows for
systems testing and commissioning.
- Develop contract plans and specifications to
ensure that the building design is at a suitable level of building
performance.
- Create effective incentives and oversight.
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