In Site Development
"Every time we design a building, we set up its energy consumption pattern and its greenhouse gas emissions pattern for the next 50 to 100 years."
Ed Mazria*
* http://www.inhabitat.com/2007/01/29/interview-ed-mazria-from-architecture-2030/
Green building considers the building's life cycle, from siting through design, construction, operation, maintenance, renovation and deconstruction. Primary tenets of sustainable design are low-impact development, passive design, the synergistic strategies of integrated design and energy-efficiency maximization.
Low-impact Development
"Low-impact development aims at maintaining the natural hydrology as much as possible within the limits imposed by the site. It entails minimizing impervious areas, maintaining natural slopes and depressions in the landscape, infiltrating and storing rainwater, and carefully selecting materials for maximum benefit to the ground and water with minimal harm. For example, preserving the old, mature trees is not only an aesthetic benefit and a source of shade canopy in warm weather, but it goes a long way to reducing runoff.”
The fundamental approach of using micro-scale management practices and source control has great potential to generate substantial benefits in existing urbanized watersheds. LID principles and practices are particularly well-suited to ultra-urban areas because most LID techniques, like rain gardens and tree planter boxes, use only a small amount of land on any given site. Many LID practices, including bioretention, are good for urban-retrofit projects since they are easily integrated into existing infrastructure, like roads, parking areas, buildings and open space.
LID practices can be applied to all elements of the urban environment. For example, bioretention technology can effectively turn parking-lot islands, street medians, tree-planter boxes and landscaped areas near buildings into specialized stormwater-treatment systems. Developers can redesign parking lots to reduce impervious cover and increase stormwater infiltration while optimizing parking needs and opportunities. Innovative designs for urban areas may also include roof gardens, methods for capturing and using rainwater, and use of permeable pavement in low-traffic areas, parking areas and walking paths. Furthermore, LID strategies can help beautify the urban environment and create desirable public open space."*
Local permitting agencies can use LID as a model in revising local zoning and subdivision regulations in favor of more cost-effective, ecologically sound development practices.
Developers can achieve greater project success and cost savings through the intelligent use of LID.
Designers can apply these techniques for innovative, educational, and more aesthetically pleasing sites.
Important Resources
US EPA Low Impact Development: http://www.epa.gov/nps/lid/
*National Resources Defense Council http://www.nrdc.org/water/pollution/storm/chap12.asp
Low Impact Development (LID) Urban Design Tools Website http://www.lid-stormwater.net/index.html
Synergistic Strategy
The very essence of integrated design is the blending of these elements and systems to solve numerous problems with interrelated benefit: one idea creating many solutions. For example, a design that emphasizes daylighting and cross-ventilation reduces the need for electricity to maintain ambient air temperatures and adequate lighting. The Energy Policy Act of 2005 defines a "high performance building" as a building that integrates and optimizes all major high-performance building attributes, including energy efficiency, durability, life-cycle performance and occupant productivity. Low energy, zero-carbon building begins with passive-design strategies, i.e. site orientation, operable windows, funneling and baffling wind, collecting and dispersing heat through interior thermal mass and exterior shading. It then integrates those strategies with mechanical systems powered by renewable resources – e.g., solar panels, wind turbines, geothermal heat-exchange systems, bioremediation and agile-energy systems – making the building's envelope an active component of the design.
Incorporating a green roof or walls into the design of multi-family housing may cost more initially, but provides the multiple benefits listed below. Ultimately, a living membrane can actually reduce the life-cycle cost of the project, and qualify the developer for green-building certifications and financing incentives that attract green investors. It also helps to bring down the ambient temperature for a broader area and increase the diversity of plant and bird life in the city by replacing the landscape that was sacrificed to the building's footprint. Such synergy, and the potential for great benefit and the lowest additional cost, occurs only in green building.
A green roof (or wall system)
- decreases summer roof temperatures by 70 degrees and cooling costs by 10%
- reduces amount of publicly owned land, and resultant costs, needed for stormwater-management practices
- provides an extra layer of insulation
- provides for sound attenuation
- delays flow and reduces stormwater runoff to overtaxed sewer systems
- can be designed to integrate with a graywater re-use system
- filters dangerous particulate matter from the air and heavy metals from the water
- reduces ambient air by 10 degrees or more compared to urban heat islands
- precludes the need for treatment for UV damage or replacement of shingles or tiles
- lasts longer (up to 50 years ) than conventional roofing materials
- provides a regenerative environment for natural grasses, birds and insects
- can provide for rooftop gardening and harvesting
What is more, Biotechture Ltd, a UK company specializing in sustainable-facade greening systems, has suggested the greatest benefit may occur from retrofitting biomembranes into existing buildings, as they will always make up the majority of the building stock.
Important Resources
Building Green - Integrating Agriculture into the Built
Environment
http://www.buildinggreen.com/auth/article.cfm/2009/1/29/Growing-Food-Locally-Integrating-Agriculture-Into-the-Built-Environment/
Heat Island
Video segments demonstrating thermal gradient differences between developed and undeveloped areas
http://www.epa.gov/heatisland/about/videos.htm
American Association of Landscape Architects Green Roof
Central http://www.asla.org/
Greenroofs 101 and Green Roof and Green Walls database http://www.greenroofs.com/
Integrated Design Collaborative http://www.integrativedesign.net/resources
Getting Aggressive about Passive Design, McGraw Hill Construction http://continuingeducation.construction.com/article.php?L=5&C=208&P=1
AeroTurbine - Becker's Darrieus and Savonious Combination
http://www.youtube.com/watch?v=iPuWSBYMWqg&feature=related
Rana Creek http://www.ranacreek.com/
Green Roofs http://www.greenroofs.org/resources/GRIM_Fall2006.pdf
http://www.greenroofs.org/resources/GRIM_Fall2007.pdf
Verdant SurfacesGreenSource magazine September 2008 Continuing Education Center http://continuingeducation.construction.com/article.php?L=5&C=440
Plan for Net Zero
A net-zero building is designed to rely on renewable energy, and could be designed to use passive-solar energy exclusively. A net-zero building need not be attached to the grid, but depending upon its size and energy source, it may generate more energy than it can use in a given period and will need a system for storing the excess. While a net-zero building is hooked up to the grid, it does not draw more energy from the grid than it contributes, within a 12-month period. Typically, photovoltaics or wind turbines generate all of the building's net energy need, returning excess energy back to the grid on optimum days, while drawing energy from the grid on days when the atmosphere is cloudy or still.
EPA's online Power Profiler offers a calculator for determining the carbon footprint of any building www.epa.gov/cleanrgy/powerprofiler.htm
The Home of Carbon Management: How to Calculate
the Carbon Footprint of any Location
http://www.carbonfootprint.com/
Elements of Building Green
Green-building codes, rating systems and building guidelines share the elements outlined below. The Department of Energy Smart Communities Network provides a comprehensive overview of the elements of green building and includes links to publications, local success stories, and sites with information on green-building construction and materials. An expanded discussion of these elements can be found at http://www.ciwmb.ca.gov/GREENBUILDING/Basics.htm
Siting
- orient east-west with southern exposure to take advantage of passive solar
- follow existing land forms, natural features and drainage patterns
- locate near mass transit and services
Energy Efficiency
- maximize natural lighting with south-facing windows, reflective awnings and skylights
- design for a tight building shell with good ventilation
- control sunlight with shading devices
- reduce or shade glass surfaces on east and west exposures
- regulate heat with thermal mass flooring
- install high R-value wall and ceiling insulation, and low U-value windows with a Low-E coating
- Install high-efficiency lighting systems, motion-sensor dimmers, task lighting
- maximize light colors for roofing and wall-finish materials
- use Energy Star appliances
- integrate alternative energy sources – photovoltaics, fuel cells, wind turbines, geothermal heating and cooling, solar hot-water systems, green roofs and walls
- plant deciduous trees on the south side
- design electrical and mechanical systems and the building envelope with the benefit of computer modeling
Materials Efficiency
- use preassembled and climate-tested integrated-systems components for thermal, moisture and air protection
- design to conform to standard-sized building materials to cut construction costs and waste
- reuse and recycle construction and demolition materials to divert debris from landfills
- specify Forest Stewardship Council (FSC)-certified wood for framing, flooring, trim, cabinets, decking and fencing
- use rapidly renewable materials, typically harvested within a 10-year cycle: ex: bamboo, wool, cotton-batt insulation
- use engineered wood for its greater strength and 45%-less lumber content
- use formaldehyde-free insulation, preferably cellulose with a typically 85% recycled content
- use materials harvested, extracted and manufactured regionally wherever possible
- use recyclable materials
- include space for recycling collection and waste management
Water Efficiency
- design for dual-flush toilets and a graywater system for site irrigation
- minimize wastewater by using ultra low-flush toilets, low-flow shower heads and other water-conserving fixtures
- use a recirculating system for centralized hot water distribution
- install tankless water heaters
- irrigate with a drip system and meter the landscape separately from buildings
Occupant Health and Safety
- use low- or zero-VOC (volatile organic compounds) paint, construction adhesives and caulks without solvents, and construction sealants free of hydrochlorofluorocarbons (HCFCs)
- use natural-fiber carpet or carpet of recycled content with low VOC underlay
- use formaldehyde-free, medium-density fiberboard (MDF) for cabinets and counter substrates
- install a high-efficiency HVAC system resistant to microbial growth, that maintains positive pressure to resist air leakage, prevent backdrafts and control humidity
- provide effective gravity-flow drainage from the roof and surrounding landscape
Building Operation and Maintenance
Engage building commissioning to:
- test and adjust the mechanical, electrical and plumbing systems to ensure that all equipment meets design criteria
- instruct the staff on the operation and maintenance of equipment
- conduct ongoing measurement, adjustment and upgrading
Important Resources
The Affordable Housing Energy Efficiency Handbookhttp://h-m-g.com/multifamily/AHEEA/Handbook/default.htm
US Department of Energy Efficiency and Renewable Energy Building Divisions Program
http://www1.eere.energy.gov/buildings/
2008 Efficiency Standards for Residential and Nonresidential Buildingshttp://www.energy.ca.gov/2008publications/CEC-400-2008-001/CEC-400-2008-001-CMF.PDF
Whole Building Design Guide: Gateway to Up to Date Information on Integrated Whole Building Design Techniques and Technology http://www.wbdg.org/design/
Sustainable Building Toolkit http://www.ciwmb.ca.gov/Greenbuilding/ToolKit.htm
GREENGUARD Environmental Institute ANSI Authorized Standards Developer, GEI establishes acceptable indoor air standards for indoor products, environments, and buildings: http://www.greenguard.org/Default.aspx?tabid=22
Green from the Ground Up: Sustainable, Healthy and Energy-Efficient Home Construction. David Johnson and Scott Gibson, Taunton Press, 2008 [David Johnson is founder of www.greenbuilding.com]
Home Building Industries Toolbase Services Building Systems, Design & Construction Guides, Construction Methods and Best Practices http://www.toolbase.org/ |
