Iano's backfill

Complexities of Sustainability

LEED as the Definition of Sustainability
Can LEED Survive the Carbon-Neutral Era (Metropolis, November 2007) discusses the growing acceptance of the US Green Building Council LEED rating system while also considering future challenges to its relevance:

• USGBC claims 40,000 LEED-accredited professionals. The organization has certified only roughly 1000 buildings since its inception.
• A recent study by construction consultant Davis Langdon claims that LEED-certified buildings, at least up to the Gold certification level, need not cost more than conventionally designed buildings. Fiona Cousins of ARUP New York estimates it can cost $100,000 in service fees to document building performance for LEED.
• Until June of this year, buildings could achieve LEED certification without receiving any energy performance points associated with reductions in carbon emissions.
• ASHRAE, in conjunction with USGBC and others, is promoting its Advanced Energy Design Guides which target energy savings of 30% over current national  standards. ASHRAE intends to introduce similar mandatory standards by the year 2012. ASHRAE and the AIA are proposing national legislation that would require new buildings to be fully climate-neutral by the year 2020.

The article also discusses the pros and cons of the LEED "checklist" methodology for defining sustainability, in contrast to more ntegrated approaches to sustainable building design. And the article speculates on the possibility of LEED's broad definition of sustainability, which includes considerations of site and community development, materials and resources, and indoor air quality, being preempted in the future by the need to focus more narrowly on the conservation of water and energy.

Separately, The Battle for Green Building (Springfield Business Journal, 12/11/20067) discusses the Green Building Initiative's Green Globes sustainable building certification program, an alternative to the better know LEED. Though there are many similarities between these two programs, Green Globes is reportedly distinguished by its pending certification by the American National Standards Institute, and its lower implementation cost than LEED.

PVC as a Sustainable Material
The USGBC's February 2007 Assessment of the Technical Basis for a PVC-Related Materials Credit for LEED is the that organization's final report on the contentious issue of the use of PVC materials in building construction.

USGBC has been considering this issue since at least the year 2000. The Assessment looks at four common PVC applications: siding, drain/waste/vent piping, resilient flooring, and window frames. Each is compared with common alternatives, for example in the case of siding, with aluminum, wood, and fiber-cement. Materials are evaluated on a number of bases:

• Conventional life-cycle assessment in which all the resource and pollution inputs and outputs associated with the material-- beginning with its harvesting or extraction and ending with its reuse or disposal at the end of its service life--are considered. Impacts on both human health and the environment are included.
• Extended end-of-life analysis in which potential PVC dioxin emissions from backyard burning and accidental landfill fires are considered. Given the large uncertainties in the data for this scenario, upper, middle, and lower range estimates were evaluated.
• Risk assessments of the adverse human health effects due to exposure to toxic compounds generated throughout the life cycle of the materials.

The conclusion: No single material shows up as the best across all human health and environmental impact categories, nor as the worst.

The assessment's results resist simplistic conclusions. Material rankings vary depending on how environmental and human health impacts are prioritized. In other words, a choice of one material over another may benefit human health while increasing adverse effects for the environment, or vice-versa. Rankings also vary with the product category. Only in the resilient flooring category do PVC products rank consistently higher in both adverse human health and environmental effects than alternative materials (linoleum and cork).

Meanwhile, Schwarzenegger Bans PVC Additive In Toys (Healthy Building Network, October 25, 2007) reports that, despite claims made by the Vinyl Institute regarding the safety of PVC in children's toys, the state of California has passed legislation prohibiting the use of phthalates, a PVC plasticizer, in products intended for babies and children under three years of age. The article goes on to state:

Like the human carcinogens vinyl chloride and dioxin, phthalates are uniquely associated with PVC. It is this triple threat from PVC that distinguishes it as the worst plastic for environmental health and green building. Regrettably, there are still few restrictions on the use of vinyl in green buildings.

Evolving Measures of Material Sustainability
Shedding Light On The Pharos Project (Eco-Structure, December 2007) describes the Pharos Project, an ambitious building products rating program under development by the Healthy Building Network.

The Pharos Project is touted as a database of building materials intended to allow a more comprehensive and sophisticated evaluation of the sustainable attributes of materials than is currently offered by other rating systems. Its unique framework covers a broad range of health, environmental sustainability, and social justice criteria.The Project will also host a Wiki and online forums.

A visit to the Project's web site leaves one questioning whether the Project is alive and well. The most recently dated content appears to be from November of 2006. According to Eco-Structure, the next working version of the Project is scheduled for release in the spring of 2008.

Measures of Sustainable Buildings
Energy Performance Data Largely Lacking (ENR, November 12, 2007) reports that, despite the attention being given to green building design, there is a lack of standards for collecting and analyzing building energy performance data, and, though newer buildings may be designed to be more energy efficient than older buildings, building energy use overall continues to climb:

• According to the U.S. Department of Energy, commercial buildings consumed 18 quads (18 quadrillion BTUs) in 2004, and are projected to consume 25 quads--almost a 40 percent increase--by the year 2030. The largest part of this jump is attributed to increased use of electrical equipment and the increased cooling loads that result.
• Between 1980 and 2000, energy use per square foot in commercial buildings increased by roughly 25 percent.

LEED certification does not necessarily correlate with reduced building energy consumption. On the one hand, Seattle's LEED-Silver Alley24 mixed-used development, completed in 2006, is reportedly close to achieving a 50 percent targeted reduction in CO² emissions. On the other hand, Seattle's new City Hall, also LEED-Silver, completed in 2003, is separately reported as consuming significantly more energy than the larger, older building that it replaced.

Carbon Neutral Building Design

Green Building Studio Inc. has launched version 3 of their Green Building Studio web-based software for analyzing the energy impacts of alternative building designs. According to GBS, in less than 3 hours you can register your project, submit your BIM building model, review results with your consultants, and tune building parameters to optimize the whole building energy use. The software addresses carbon neutral building, US EPA Energy Star scores, water usage, daylighting, natural ventilation, and other factors.

The BuildCarbonNeutral calculator estimates the C02 emissions of a proposed building based on its size, method of construction, and location. Jointly developed by Mithun Architects and the Lady Bird Johnson Wildflower Center, the tool purportedly:

estimates the embodied energy and subsequent carbon amounts released during construction. The measurements account for building materials, processes and carbon released due to ecosystem degradation or sequestered through landscape installation or restoration.

Standards: New (costly?), New (better?), and Needed(?)

ENR's Third Exit Stair Could Make Highrises Too Costly to Build (June 4, 2007) reports on the adoption of more stringent life safety requirements for tall buildings in the 2007 Supplement to the International Building Code. Both the Building Owners and Managers Association International and the American Institute of Architects oppose as too costly a new requirement for buildings taller than 420 feet to have at least 3 independent exit stairs. Other changes to tall building requirements in the 2007 Supplement, all coming in the aftermath of the 9/11 attacks on the World Trade Center Buildings in New York City, include:

• protected fire service elevators and lobbies
• photoluminescent pathway markings in exit stairwells
• inspection and greater strength requirements for spray-applied fireproofing.

Proposals for progressive collapse resistance, increased  exit stairway enclosure integrity, and requirements for a a building's ability to burn without collapse were rejected. See the ICC's Code Development page for more information about that organization's code development process and the adoption of these new requirements.

In the same issue, Energy-Efficiency Guidelines Would Be National Model reports on the American Society of Heating, Refrigerating and Air Conditioning Engineer's (ASHRAE) ongoing development of Standard 89, an enhanced building energy efficiency guideline. Standard 89, now open for comments, is intended to reduce building energy consumption by 30% in comparison to ASHRAE's long-recognized Standard 90, and is being touted as a national standard for achieving LEED certified optimized energy performance. See ASHRAE's Advanced Energy Design Guides page for more about this organization's enhanced energy performance guidelines.

Lastly, Innovative Mix with Fly Ash is Still Not Widely Used describes a concrete mix composed of lime, portland cement, and fly ash developed by Nai C. Yang of the New Port Authority 38 years ago for use in airport runway construction. The mix is claimed to provide superior concrete and a reduction in environmental impact (due to reduction in cement content and, consequently, reductions in C02 emissions). However its broader use in airport construction has been hampered by unfamiliarity and a lack of standards for its production.

Green Construction News

Greenhouse (Eco-Structure, May/June 2007) reports on the National Association of Home Builder's (NAHB) February announcement of the development of a new residential building sustainability standard. To be produced in cooperation with the International Code Council, the new National Green Building Standard will be an ANSI certified consensus standard and will replace NAHB's current Model Green Home Building Guidelines.

Unlike the Guidelines, the new standard will be administered nationally, rather than at the local level, and will apply not only to single-family residences and townhouses, but to apartments and other types of multi-unit residential construction as well. Three levels of certification will be offered, Bronze, Silver, and Gold.

The standard is planned for release in February, 2008.

Trends and Challenges in Green Building (Building Safety Journal, April 2007) discusses coordination between sustainable design standards and building codes.

Historically, building codes have focused  on life-safety concerns and regulated construction so as to achieve immediately tangible benefits (such as higher resistance to fire or improved egress). More recently, some code requirements, such as energy efficiency in buildings, have been developed with the intent to provide benefits in the longer term and extending beyond the immediate users of the building.

Outside of energy efficiency regulations, coordination between long-term sustainability goals and building codes has been limited to date. Green building techniques relying on alternative building practices (for example, rammed earth construction) are frequently not addressed in the model codes. Green building programs, such as USGBC LEED or GreenGlobes, were originally formulated and continue to operate outside of the building code regulatory infrastructure.

Efforts to improve coordination between the model codes and sustainability initiatives include:

• Newer provisions within the codes themselves recognizing sustainable design practices such as insulated concrete formwork construction, unvented conditioned attics, waterless urinals, and greywater recycling systems
• Incorporation of energy efficiency standards meeting green building assessment criteria into the building codes, such as the proposed Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings (ASHRAE/USGBC/IESNA Proposed Standard 189)
• The National Green Building Standard for residential construction, currently under development by the NAHB and the ICC (see above)
• Establishment of the USGBC committee Greening the Codes
• ICC's Industry Advisory Committee's comparison of Green Globes and LEED building assessment criteria (see Reports, IAC Task Group Report Green Buildings (March, 2007)

More Info
NAHB Research Center National Green Building Standard home page
ICC Green Building page

Pollution-Reducing Cement

A Concrete Step Toward Cleaner Air (Businessweek.com, 11/8/2006) reports on the use of concrete formulated with photocatalytic agents in the construction of walls and slabs at the Italian Pavilion of the Venice Biennale. In the presence of light, Italcementi Group's TX Active proprietary cement used in the concrete mix breaks down carbon monoxide, nitrogen oxide, benzene, and other pollutants into less harmful compounds such as water, nitrates, and carbon dioxide. The basic ingredient in TX Active, a blend of titanium dioxide, can be added to cement, mortar, paints, and plaster. Full-scale tests of the product in repaving projects in other locales have resulted in up to 60% reduction in measured pollutants.

The Vatican's Jubilee Church in Rome, 2003, (image above) was the first project to use TX-Active cement concrete.

Smog-Eating Concrete May Soon Cover US Buildings (ENR March 5, 2007) reports on the anticipated arrival TX-Active cement products in the United States via Italcementi Group's US subsidiary Essroc Cement Corp, though no specific projects are named. According to ENR, the titanium dioxide cement mix was first formulated to produce concrete with a brilliant white color, and it's pollution reducing properties were only appreciated later.

Superabsorber (transmaterial, March 8, 2007) describes the Superabsorber system designed by Douglas Hecker and Martha Skinner of fieldoffice that combines sound absorbing and photocatalytic air pollution reducing properties in sponge-like highway sound barrier walls. 

See also: Anti-Pollution Paint

Green Giant

Architecture firm SOM's very green Pearl River Tower, planned for Guangzhou, China, is described in both Super Tall and Green  (Metropolis, August 2006) and SOM's skyscraper innovation has moved to China (Architect Record, 07.06).  Included among its sustainable features are:

• An underfloor radiant cooling system that passively circulates air within the building's interior
• A sculpted building form that channels wind into turbine-driven electrical generators located on two of the building's mechanical floors
• A double-wall curtainwall system that preconditions fresh outside air and directs exhaust air to mechanical floors where excess heat is captured and reused
• Fuel cells located on-site that produce electricity more efficiently than that available from the public grid; Waste heat from the fuel cells is also recycled into the building's heating and cooling systems.
• A condensate reclamation system to reduce HVAC system water consumption

The 1000-ft tall building is scheduled for completion in Fall 2009. According to Metropolis Magazine, the building is designed to be the world's first "zero-energy supertall building in the world," though this claim is not fully explained.

Recycled Waste In Concrete Construction

Slab Alternatives From Recycled Waste (Architecture 04/2006) describes two proprietary Swiss systems from using recycled waste products in concrete to provide lighter-weight, better-performing concrete products.

Cobiax Technologies manufactures a system of hollow recycled polyethylene plastic spheres integrated with steel reinforcing cages that may be used to construct sitecast or "semi-precast" concrete floor slabs. This slab system can span from approximately 5 to 20 meters (15 to 65 feet) with thicknesses ranging from 230 to 580 mm (9 to 24 inches), capabilities roughly comparable with sitecast concrete one-way joist systems or precast concrete hollow core slabs.

In comparison to conventional concrete systems, the manufacturer claims weight savings of up to 35%, and additional potential savings through reduction in construction time and simplification of concrete forming requirements.

Geofil manufacturers glassy spheres from recycled waste, with sizes ranging from 2 to 25 mm (1/16 to 1 inch) in diameter. When added to concrete, the manufacturer claims a lighter-weight material with improved heat resistance and higher insulating values is produced. 

Is PVC OK?

Vinyl, wood, and sustainability (Building Design & Construction, 02.05) comments on the USGBC's recent draft report on the use of vinyl materials in building construction. Contrary to the expectations of many involved in the green building movement, the report takes no strong position regarding the issue. Building Design & Construction's editorial lauds the "courage and intellectual integrety" of the task group and the manner in which this controversial issue is being studied.

Prepared by the USGBC PVC Task Group, the report's executive summary states in part:

The available evidence does not support a conclusion that PVC is consistently worse than alternative materials on a life cycle environmental and health basis...Therefore the current body of knowledge [report's emphasis] as analyzed in this report does not support a credit in the LEED rating system for eliminating PVC.

According to the report, USGBC's consideration of a LEED credit for the avoidance of PVC in construction materials goes back to the year 2000, and its Technical and Scientific Advisory Committee was tasked with studying the issue in November of 2002. Tasks remaining in the evaluation process include solicitation of stakeholder comments, preparation of a final report and recommendations, and development of a final USGBG position.

More Info
Questions about materials strain the fabric of USGBC’s big tent (Architecture Record, 03.05)
c3.org: By the Chlorine Chemistry Council, advocating the benefits of PVC.
PVC Alternative Database: By Greenpeace International, describing the detriments of PVC and more desirable alternatives.

Building Design & Construction Sustainability White Paper

Progress Report on Sustainability is Building Design & Construction Magazine's 2004 edition of its annual white paper on the green building movement in the US. For anyone interested in the the state of sustainable building in this country, or in where this movement is headed in the upcoming year, this report is a must-read.

The report Action Plan recommends the USGBC:

• Coordinate more closely with Federal agencies and regulators
• Seek stronger sponsorship from the executive branch
• Eliminate code requirements and other regulations that discourage or restrict sustainable design
• Continue to document the health and performance benefits of green building in schools
• Promote a national program to reduce construction and demolition waste by 50% in five years
• Seek progress in the green homes sector, balancing sustainability goals with the high competitive cost pressures of this market segment

From the report's reader survey:

• Green know-how does not appear to be a strong attraction for clients choosing design professionals.
• First costs are still seen as the single greatest barrier to green design.
• Green products should be evaluated on a cradle-to-grave life cycle basis rather than solely based on energy and environmental impacts.
• Designers have trouble sourcing green products because "green" is not always clearly defined, green products are difficult to find or obtain, and manufacturer claims for the green products do not always seem trustworthy.
• Respondents want independently documented evidence of the benefits of green building in comparison to conventional construction techniques.

USGBC continues to develop its various green building categories. In addition to the now four-year-old New Construction (NC) category, Existing Building (EB) and Commercial Interiors (IC) categories were rolled out in this past year, and the Core & Shell (CS) category is "well into its pilot phase". Some particularly interesting statistics regarding existing buildings from this section of the report include:

• 75% or more of the lifetime costs of a building go into operations and maintenance.
• Existing buildings, including homes, consume nearly 40% of the nations energy, add 40% to its atmospheric emissions, consume 12% of its fresh water and 88% of its potable water, and account for 40% of its municipal solid waste. They also consume 40% of all wood and raw materials used in US construction.

Additional articles in this white paper discuss aspects of green building related to first costs, state and local regulations, "high performance" schools", residential construction, health care facilities, and more.

Sustainability And The Highrise

Sustainability and highrise construction appears as a topic in a number of recent publications.

Innovation, a November 2004 supplement to Architectural Record magazine, is devoted to highrise design and includes considerations of sustainability from a variety of perspectives:

In lead editorial Aiming High, Robert Ivy discusses Norman Foster and Partner's new Swiss Re building (also known as 30 St. Mary Axe). Foster's building uses a dual-glazed skin to convert convective air flow into power, heat, and lighting for the building interior. As air within the curtainwall sandwich is warmed by solar heat gain and rises, it is captured by various mechanical systems and then turned into useful energy and heating.

In Do skyscrapers still make sense? the relationship of highrises to revived downtowns and the urban business environment is discussed:

_Three years after the attacks on the World Trade Center Towers, financial firms for the most part have decided to remain located in New York City's financial district, despite the costs. The benefits of the "human network"--face-to-face, close, personal interaction--outweigh the location's higher costs and risks.

_European cities are losing their traditional resistance to highrise development, recognizing the amenity and economic efficiency this building type can offer. London's new towers are characterized as modestly proportioned so as to minimize casting shadows on neighboring areas, and sustainably designed with daylighting, informal spaces for impromptu meetings, and individually controlled natural ventilation.

_Holistic approaches to building physics, more common in Europe than the US, use air buoyancy effects, diurnal temperature cycles, natural ventilation, breathable skins, localized control of heating and cooling, and passive shading to strategically reduce building energy requirements. Systems that rely less on mass air movement than traditional HVAC approaches can also result in reduced floor-to-floor heights bringing additional economies.

The thrust of this article is perhaps best summed up by Craig Schwitter, structural engineer with Buro Happold in New York, quoted as saying, "I don't believe the challenges are in making towers bigger, but more livable."

In Green grows up...and up and up and up the recent surge in design of green highrises for New York City is discussed, including projects such as:

• _Renzo Piano Building Workshop and Fox & Fowle Architect's New York Times Tower
• _Cook + Fox Architect's One Bryan Park
• _Foster and Partner's Hearst Tower
• _SOM's Freedom Tower (in regard to the proposed wind turbines)
• _Cesar Pelli & Associate's  211 Murray Street residential building

Numerous sustainable design strategies are discussed, such as passive solar screens, daylighting, rainwater collection and reuse, underfloor air distribution, cogeneration, photovoltaics, adaptive reuse of existing building shells, slab-integrated cooling and heating, and more.

Building Safety Bulletin's High-Efficiency High-Rise Breaks Ground (November 2004) discusses New York City's Bank of America Tower, the first US highrise aiming for USGBC Platinum LEED rating. Sustainable technologies include double-wall skin, translucent insulating glazing, natural daylighting, automatic dimming of artificial lighting, planted green roof, on site cogeneration, ice-based thermal storage, underfloor HVAC with individual floor air handling units, and more.

New Yorker Magazine's Green Manhattan (October 18, 2004) is a highly readable article espousing the green benefits of living in Manhattan. The short story: If Manhattan were the fifty-first state, it would be the country's 12th largest based on population, but its energy use on a per capita basis would be the lowest of all. Read the article to learn more :)

NY Time's Full-Scale Lighting Tests

A Day In The Light, Metropolis, May 2004, describes the New York Time's full-scale mockup of a portion of a typical floor of their planned 51-story Manhattan high rise. The mockup is being used to evaluate numerous aspects of the design, including:

• office furnishings
• lighting and controls
• constructability
• user reactions to the space.

Evaluating lighting strategies is one of the mockup's primary and most interesting purposes. The 4300 sf mockup simulates the southwest corner of a typical office floor, the quadrant most affected by exposure to direct sunlight. Daylight control is accomplished with a combination of exterior shading elements and computer controlled motorized shades. Two control systems are being evaluated. One responds to ambient exterior lighting conditions analyzed in combination with a database of seasonal and time of day lighting information. The second system monitors and responds to interior lighting levels. Each of these daylight control systems is paired with one of two separate systems for controlling interior artificial light levels. Lighting data from the mockup is being recorded at Lawrence Berkeley National Laboratories (LBNL) every 60 seconds around the clock, and the tests are being run from winter solstice to summer solstice to capture the fullest range of solar exposure conditions.

Since the mockup represents only one-sixth of a typical floor plate, lighting conditions for the remainder of the floor are being modeled in computer using LBNL's Radiance software. By synchronizing the computer model to the data coming from the mockup, results can be generated for the remainder of the floor with a high degree of confidence. Human factors surveys are also a part of the testing protocol.

Designed by Renzo Piano, the building will be located on Eight Avenue, between 40th and 41st Streets, in New York City.

More Info
Radiance software

Sustainable Design: Costs & Energy Savings

Various items in Eco-Structure, February 2004, offer perspectives on the long-term costs/savings and energy use implications of sustainable design, including:

• Classic Homes Get Energy Boost describes Chicago's Green Bungalow Initiative. This program provides guidance to homeowners for energy efficient renovation, including use of fluorescent lighting fixtures, energy efficient windows, Energy Star rated appliances, low-flow plumbing fixtures, products with high recycled content, and unique systems for heating, cooling, and water supply. Four model homes demonstrated actual energy savings of 47% to 69%, compared to projected savings of 38% to 72%. Life-cycle cost analysis project life-cycle savings from 12% to 157%, with payback periods of 5 to 12 years.
• Statistics Show Newer Homes Use More Energy reports on a US Department of Energy Information 2001 survey. The survey indicates that new homes are using more energy than older homes, despite the use of more energy efficient technology in newer homes. This apparent contradiction seems to stem from newer homes' larger size and their owners' tendency to run more energy consuming devices.
• Study Proves Green Buildings Are Cost-Effective describes a comprehensive cost analysis of sustainable-built projects. The study, conducted by Capital E Group, Lawrence Berkeley National Laboratory, and other California state agencies shows sustainable building increases up-front construction costs by about 2 percent, but results in life-cycle savings of 20 percent on average of construction costs. The report assesses green design value at about $50 per square foot for LEED Certified Silver buildings and $70 per square foot for Certified Gold and Platinum buildings when calculated over a 20 year life span. By this author's calculations, approximately 70% to 80% of this value appears to derive from occupant productivity and health gains. The remainder comes from savings in operation and maintenance, energy use, emissions, water, and construction waste (listed here in order of decreasing contribution).

Simpler Energy Codes Coming?

DOE Aims for Simpler Energy Code, Journal of Light Construction, March 2004, discusses efforts by the US Department of Energy to encourage simplification of the International Code Council's International Energy Code. According to the article, the proposed changes are intended to be "result-neutral", in that they will not increase or decrease baseline energy use requirements from the current version of the Energy code. But they will "drastically simplify" the code's prescriptive and performance based requirements. The article paraphrases DOE sentiments as "A strict energy code accomplishes little if it's too complicated to understand or enforce."

Some of the proposed changes include:

• Reduction in the number of US climate zones
• Simplification of climate zone boundaries by running boundaries along state lines where possible
• Elimination of window area restrictions
• Elimination of window-to-wall restrictions
• Allowance for building element tradeoffs that meet or exceed prescriptive requirements

The deadline for final public comments is April 2004.

More Information
DOE: Building Energy Codes - 2004 DOE ICC Code Proposals

Trends In Metal Roofing

Metal With Pizzazz, Building Design & Construction, 02-04, reports on new materials and coatings in the metal roofing market, such as:

• New, infrared reflective pigments allow dark-colored coatings to achieve higher levels of solar reflectance and infrared emittance. These so-called "cool" color pigments result in lower roof temperatures on darker-colored roofs, allowing these roofs to meet EPA EnergyStar/LEED standards for reducing building heat island effects.
• According to the article, alternatives to traditional coated metal roofing, such as stainless steel, titanium, zinc, and aluminum, are gaining market acceptance. With stainless steel and titanium, the protective oxide layers that form naturally on these metals can be manipulated to affect their appearance. By precisely controlling the thickness of the oxide layer, light interference effects result in a unique, colorized appearance that is virtually fade-proof.
• Other processes can be used to alter the natural patinas of zinc, copper, and other roof metals.

Also according to the article, the Cool Metal Roofing Coalition trade association, is currently working with the US Green Building Council to advance the credits attainable for cool metal roofing in the next LEED version. The Coalition is also working with the state of California to advance recognition of uncoated metal roofing in the next version of that state's Title 24 energy code.

Cool Metal Roofs and Sustainability
Cool metal roofs can contribute to meeting sustainability goals for a project under current LEED standards. The US Green Building Council's LEED New Construction Version 2.1 Rating System, Sustainable Sites Credit 7.2, awards one point for high-reflectance, high-emissivity roofs that contribute to reducing heat islands. Cool roofs can also contribute to building energy performance which is awarded points under Energy & Atmosphere, Prereqs 1 through 3 and Credit 1.

The Cool Roof Rating Council, another independent standards association for rating radiative roof performance, claims the following benefits for cool roofs:

• Lower your utility bills for air conditioning
• Down-size your air conditioning systems
• Expect lower roof maintenance costs and longer roof life
• Enjoy greater occupant comfort
• Use this low-cost energy efficiency measure for meeting building codes


• Help address your community's heat island effects

Anti-Pollution Paint

Smog-busting paint soaks up noxious gases, New Scientist, February 4, 2004, reports on Ecopaint, a coating product that asbsorbs nitrogen oxide (NOx) emissions.

Ecopaint is scheduled to go on sale in Europe in March of this year. The coating relies on embedded particles of titanium dioxide and ultraviolet radiation from the sun to catalytically convert NOx gasses to nitric acid. The nitric acid is then either washed away by rain or neutralized by other embedded calcium carbonate particles. The success of the coating depends on the paint's unique polysiloxane base which, unlike other paint bases, is itself resistant to reacting with the titanium dioxide embedded in the coating. A 0.3-millimeter (12-mil) thick coating is expected to have a 5-year lifespan before exhausting the capacity of the calcium carbonate to neutralize the nitric acid. (Left unneutralized, the nitric acid may cause color changes in the coating.)

This article also discusses Europe's Photocatalytic Innovative Coverings Applications for Depollution Assessment program, and its experience with catalytic cement coatings for roadways that have demonstrated success at significantly reducing NOx gas levels as well. This program is part of EU-member countrys' efforts to reduce NOx levels to below an annual average of 21 parts per billion by the year 2010, a reduction from current levels of 10 times or more for some urban areas.

Plastic Bridge Faring Well

One-year-old plastic bridge exceeds expectations, Structural Engineer, January 2004, reports on the current health of the nation's first all plastic bridge, the New Jersey Pine Barrens Mullica River Bridge, first covered on this site last November.

According to the article:

• After more than one year in service, the one-lane, 56-foot long bridge is so far exceeding expecations.
• The structural plastic material is a combination of polystyrene and polyethylene, recycled from items such as milk cartons, soda bottles, and foam cups.
• The bridge is rated to carry a 36-ton load and cost $75,000 to build. Costs to replace the original wood structure were estimated at $350,000.

Also according to the article, the Federal Highway Administration currently has sponsored more than 40 projects involving experimental plastic materials and sees an "incredible" market potential for these materials.

Plastic Wrap for Buildings?

The Cleverest Building Material Around, The Sustainable Metropolis, describes SmartWrap, a thin, plastic membrane material under development for use as a complete building cladding system. Product developers James Timberlake and Stephen Kieren of KierenTimberlake Associates claim the material has the ability to change color and appearance, perform the functions of shelter and control of interior climate, and provide light and electricity. The membrane's heating, lighting, information display, and energy collection and storage capabilities can all be controlled by computer, either on- or off-site.

Finally, in an apparant hat trick, the material is claimed to be 100% recyclable.

Inexpensive, Green Housing

Cheap Homes, Rich Benefits, ENR, January 12, 2004, describes Chicago area developer-built low-cost housing that is also energy efficient and environmentally friendly. Developed by Claretian Associates, an area non-profit developer, the homes are being constructed through the City's New Homes program, which according to the article has freed up approximately 1600 abandoned or underutilized lots for redevelopment.

Green features include:

• Low-VOC interior and exterior paints
• High efficiency gas furnaces
• Low-flow toilets and plumbing fixtures
• Recycled glass bathroom tiles
• Cork kitchen flooring
• Insulated glazing window units
• Recycled plastic carpeting
• Recycled wallboard and structural insulated wall panels
• Wood-polymer composite porch decking

The economics of the units is also interesting. Lots are granted to developers for as little as $1 each. According to the article, the additional cost for using green materials is approximately $4000 per house. Qualified low-income families can receive $10,000 to $30,000 in buyer subsidies. The first tweleve buyers will also receive 1.2 kw rooftop photovoltaic systems, estimated to save several hundred dollars each year in energy costs. These photovoltaic systems are being provided at no cost through subsidies provided jointly by Chicago's Department of Commerce and Economic Opportunity, local utility Commonwealth Edison, and local supplier Spire Solar Chicago. Single-family unit purchase costs are between $123,000 and $165,000.

Top 10 Green Products

BuildingGreen, Inc., publishers of Environmental Building News, have released their 2003 BuildingGreen Top-10 Products . The list includes pigments, insulations, vapor retarder membranes, paints, interior finish armor, laboratory casework, office chairs, hot water systems, and faucets, all of which earn high marks for their green, enivornmnetally friendly attributes.

Portland Cement Gets Greener

[This image shows a rotating cement kiln used in the manufacture of Portland cement. The scale is deceiving. Note the small human figures standing on the facility floor toward the bottom right of the image.]

The Portland Cement Association (PCA) is in the later stages of spearheading changes to the formulation of portland cement according to the ASTM C 150 standard. By allowing the inclusion of up to 5 percent ground limestone, PCA estimates annual enivironmental benefits including:

• Reduction in raw materials use of 1.6 million tons
• Reduction in energy use of over 11.8 trillion BTUs
• Reduction in carbon dioxide emissions of over 2.5 million tons
• Reduction of cement kiln dust of over 190 thousand tons

According to PCA's November 13, 2003 press release, the proposed changes will result in a 2.6 percent reduction in carbon dioxide emissions per ton of product, part of PCA's longer-term goal to reduce such emissions by 10 percent between 1990 and 2020. PCA also claims to have reduced energy consumption in the manufacture of portland cement by 33 percent since 1975.

More Information:
The manufacture of portland cement is discussed on pages 469 - 471 of the textbook. Issues of sustainability in concrete construction are discussed on pages 472 - 473.
PCA's Cement Basics page provides information on the formulation of portland cement, blended cement, and hydraulic cement, and provides links to additional related topics.

The Benefits of Schools Built for Sustainability

The Sustainable Buildings Industry Council is offering a free video series about "...how High-Performance School Buildings boost student health and productivity, conserve energy and water and other natural resources, and save communities money."

Major topics include:

• Overview of High-Performance School Buildings
• Building Blocks of a High-Performance School Building
• Benefits of a High-Performance School Building
• How do you Create a High-Performance School Building: Eight Steps for Managing the Process

This is a worthwhile resources for design professionals and educational facility clients alike.

Pervious Concrete

Pervious Concrete Pavement: A Win-Win System, Concrete Technology Today, August 2003, a three times a year newsletter from the Portland Cement Association, discusses concrete pavements with high porosity. Also known as no-fines concrete or porous concrete, this 50-year old technology is gaining renewed attention for its ability to contribute to improved storm water management.

Unlike conventional concrete mixes, the aggregate in pervious concrete is narrowly graded. By omitting smaller sized aggregates, and limiting the amount of cement paste, interconnected voids may constitute 15% to 35% of the final concrete after curing. The interconnected void spaces allow water to pass through the concrete and percolate into the ground below. According to the article, percolation rates of pervious concrete may range from 2 to 18 gallons per minute per square foot of surface. The large percentage of void space also makes pervious concrete lighter and less strong than conventionally formulated concrete. Its compressive strength may range from 500 psi to 4000 psi, and its density may vary from 100 to 120 pounds per cubic foot.

This article provides more information about mix design for pervious concrete, its application to various site pavement applications, and its benefits related to federal clean water regulations.

Growth of Green

Green Building Industry Grows by Leaps and Bounds, ENR November 24 2003, describes the state of the 10-year old US Green Building Council. For example:

• USGBC now has more than 3,500 members, two-thirds of which have joined in the last two years.
• USGBC's budget has grown from $400,000 in 1999 to $17 million for 2004.
• USGBC continues to refine its LEED rating system for new buildings, and is developing systems for building operation and maintenance, interior renovations, and core and shell construction.

Two issues currently being looked at by the USGBC, described as contentitious by ENR, are awarding LEED credits for alternatives to the use of halocarbons in HVAC equipment and inclusion of a PVC-related credit (i.e., award LEED credits for avoiding PVC materials).

Highrise Aspires to LEED Platinum Certification

In What Will The City Look Like in 2010: Productivity, Metropolis Magazine reports on Genzyme's new corporate headquarters in Cambridge, Massachusetts. The 12-story, 350,000 square foot building will be applying for LEED Platinum certification, the US Green Building Council's highest rating. If successful, it will become the first Platinum certified building of this size in the United States.

According to the article, sustainable features include:

• The concrete structural frame adds thermal mass that contributes to energy efficiency. The concrete filigree system makes efficient use of materials, relies on locally produced materials, and is reinforced with recycled reinforcing bars.
• Natural daylighting is achieved with a mixture of skylights, fixed and motorized mirrors, prixmatic louvers, interior reflective surfaces, and blinds.


• A double wall glazing system along with selective use of reflective glass creates an energy efficient building skin.
• Heat exchangers reduce heat loss in winter heating mode. Steam absorption chillers, running entirely on waste heat from a nearby power plant, provide summer cooling. The building's atrium allows natural ventilation. Microclimate control allows localized control of heating and cooling in as many as 50 separate locations per floor.
• A system of water sensors control a water saving, on demand irrigation system for site landscaping.
• Sustainable site strategies include brownfield site development, urban redevelopment, and public transportation access.
• The project makes extensive use of sustainable woods and recycled materials.

More Information:
What Makes Genzyme Center a Green Building? provides more information about this project's compliance with LEED goals.
Genzyme's Genzyme Center web pages provide more information about the project in general.
Atlantic City NJ Casino Collapse, on this site, provides more information on the filigree concrete framing system.

Another Moisture-Resistant Board Product

Abuse, Moisture, Mold and Fire Resistant...Who Could Ask for Anything More?, ENR November 17 2003, reports on US Gypsum's newly announced Fiberock Aqua-Tough panels. Panels are gypsum-based with a specially formulated moisture resistant core material. Purported benefits include:

• Suitable for use in wet areas, such as showers, as both a ceramic tile backer board and to receive paint above the tile line
• Mold-resistance
• Resistant to flame spread and zero smoke development
• Abuse resistant, with no easily damaged paper face to

Additionally, the panels are manufactured from 95% recycled materials, included synthetic gypsum extracted from flue gas, and shredded consumer waste paper.

White Paper On The Green Building Movement

Building Design & Construction Magazine has produced its White Paper on Sustainability, A Report on the Green Building Movement. This author highly recommends this thoughtful and comprehensive assessment of the state of the art to any serious student or practitioner of green building. Contents include the history of green building, LEED basics, survey results of BD&C's readership, developments in green building at the international, federal, state, and local levels, costs of green building, selecting green products, the future of green building and more.

Concluding Action Plan points include, in part:

• Conduct peer-reviewed studies of the benefits of green buildings related to human performance, health, and well-being.
• Enlist the real estate brokerage, financial, and appraisal community to champion a rigorous, peer-reviewed study of the economic and "business-case" aspects of sustainable design.
• Establish an Institute for Sustainable Development Research, pooling the resources of major universities, the Federal government, and the private sector.
• Launch a pilot program to measure the impact of green schools on student achievement and health.
• Reconsider the admission of trade associations to the GBC (up until now excluded from membership).
• Continue to upgrade LEED.

The Code Authority Fall 2003

The 2003 Issue of Underwriter Laboratory's online newsletter for code community includes articles on:

Fire Resistance vs. Surface Burning Characteristics discusses the difference between fire-resitance ratings for walls and ceilings, and surface burning and smoke developed limits for finish materials. In a nutshell, partitions and ceilings are rated according to their capacity to contain the spread of fire. Finishes are rated according to their propensity to spread flame along the finished surface and generate combustion smoke.

Limited Combustible Cable Category Created discusses a newly created classification for telecommunications cabling used in air plenums, where the cable's surface burning and smoke developed characteristics are a concern. The new category surpasses the current minimum requirements (in NFPA 90A) and has been developed in response to the increasing density of cabling within such spaces.

Here Comes the Sun discusses photovotaic solar electric systems and related issues such as system types, connecting to the local power grid, integration of systems into traditional building components (e.g., PV modules as part of roofing shingles), and safety issues.

Leed CS Rating

Earlier this year, the US Green Building Council released its LEED Rating System for Core and Shell.

The purpose of this separate rating system is to open up LEED certification to projects where the building developer does not control buildout of tenant spaces, when such work is contracted separately at a later date.

Rastra Insulating Concrete Formwork

Farmhouse Fusion, Fine Homebuilding January 2004, highlights an interesting insulating concrete formwork (ICF) system from the Rastra Corportation.

The insulating form units are made from 85% recycled postconsumer polystyrene waste. Units used on the project featured in FH were 10 inches thick, 10 feet long, and 15 or 30 inches in height. (The 30-inch high units required a portable hoist for lifting.) Blocks can be cut with an electric chain saw, and edges can be eased with abrasive forming tools. Stucco is a common exterior finish applied over the completed walls.

For more about ICF construction, see pages 512 - 513 in the textbook.

Structural Recycled Plastic

Plastic Fantastic, Metropolis May 2003, reports on a bridge made entirely of recycled plastic. The fifty-six foot long, single-lane bridge provides access over the Mullica River in the New Jersey Pine Barrens for hikers, forest rangers, and fire fighting vehicles. The recycled plastic, a mix of polystyrene and polyethylene, was developed by Rutgers University School of Engineering professors Tom Nosker and Richard Refree. Reported benefits include:

• Natural resistance to decay, without the need to treat with potentitally toxic chemicals
• 50-year lifespan
• Recyclability at the end of its useful lifespan

More information about this project and its development partners can be found at Rutgers Focus, March 10, 2003. The patented material is manufactured for commercial applications by Polywood Inc.

GreenBuild Conference

The GreenBuild International Conference and Expo is being held November 12 - 14 in Pittsburgh, Pennsylvania, sponsored by the US Green Building Council. Highlights include:

• Educational programs
• Making the business case: Case studies
• More than 250 exhibitors
• LEED workshops
• USGBC chapter and member days
• Green building tours
• Thought-provoking keynote speakers
• Annual USGBC Leadership Awards

Perspectives on Sustainability

Two thoughtful articles on sustainability that have come to this author's attention within the last year:

Architecture Record
In Architecture Record (02.03), Nadav Malin, editor of Environmental Building News, makes some interesting points about evaluating sustainability from a life cycle point of view. Some examples:

Maline states that where a space depends on indirect lighting, the reflectivity of the ceiling material will probably be a more important contributor to sustainability than the amount of recycled content in the ceiling tiles, when considered over the life of the building.

Low-VOC paints reduce emissions during the construction of a project. But chemical emissions from cleaning agents and other maintenance materials will impact the environment throughout the life of the building.

Maline references a study suggesting just one instance of stripping and waxing a floor releases as much VOCs as were released during installation of the original floor.

Malin proposes that the manufacture and disposal of a product are important considerations in its measure of sustainability--but these are one-time events in the life of the product. In contrast, considerations of the product's performance in the building apply throughout its useful life, and in many cases probably make a larger contribution to sustainability over the product's total life cycle.

This article also discusses some state of the art tools for evaluating the life cycle environmental impact of building materials.

Metropolis Magazine
In Metropolis October 2002, Pay It Forward, Jade Chang writes about Toyota's Los Angeles based real estate division's commitment to sustainability, and its ability to move its consultants and suppliers toward meeting the company's high standards for sustainability throughout its operations. This well-written article makes a strong case for the positive impact that can be made by an enlightened owner/client. Highly recommended reading for students of sustainability.