By Susan McClendon, CCS
Buildings have historically caused much environmental degradation, particularly by the operation of their technology components. Heating by coal and oil, electricity produced by burning fuels, sewage dumped directly into streams, and various other pollutants and contaminants produced as by-products of building services have all contributed to local, regional, and global problems.
With greenhouse gas emissions now acknowledged as a global problem and with the cost of energy and water predicted to rise continuously for the foreseeable future, building owners are greatly concerned with improving efficiencies. New and improved technologies can reduce consumption of water and energy as well as reduce the environmental impact of every building.
There are many definitions of "green" building, but this article is focused on the effects of buildings on global and local sustainability. The life-cycle operation of buildings contributes to or inhibits the sustainability of the environment much more than the initial construction does. Buildings use resources and produce by-products: inputs and outputs. Water and energy are the two major inputs - the "lifeblood," if you will, of the building's services, its technology. From this point of view, the technology is a "user," using up natural resources, and because many of the outputs, pollutants, are produced by the technology, the technology itself could be considered the problem. Because we are not going to give up our technology, because it performs functions we need, the sustainability viewpoint forces us to evaluate inputs and outputs. Just as technologies have grown up from "low tech" to "high tech," using "even higher tech" can help us reduce both inputs and outputs.
People don't buy energy or water they don't need - it's not like the dessert we crave but shouldn't eat. Reducing the need for additional water or electricity is universally desirable, and conservation is the first step. Reducing inputs to zero is unlikely - no one has invented a perpetual motion machine yet - but no one knows how much the efficiency of current technologies can be increased.
Just as the auto industry has developed cars that go farther on a gallon of gas, much of the equipment we use in buildings has already been improved to use less power and water than ever before. High-efficiency motors, long-life fluorescent light bulbs, and low-flow toilets are just a few examples. Sometimes a new invention is required to dramatically reduce consumption, but most of the time it's just a matter of manufacturers responding to consumer demand.
Another way to reduce inputs is to eliminate unnecessary use. This is basic conservation like turning off lights not in use or making sure the faucets don't drip. Although traditionally these have been occupant responsibilities, new inventions have made automatic controls possible. Simple solutions include occupancy sensors to turn off lights in unoccupied rooms, sensor-operated faucets, and night-setback thermostats. A different type is submetering in multiple-tenant buildings - tenants are more motivated to conserve because they pay the actual cost of usage rather than a flat fee regardless of usage.
The third way to reduce inputs is to make or collect your own, on-site, eliminating or reducing the amount of purchased water or energy required. On-site generation of electricity is fairly common, but on-site extraction of the fuel needed to do this is not. Sustainable local sources of energy are essentially free - sunlight, water power, geothermal energy, and by-products of the facility operation. So far, electricity-based technologies have the best chance of becoming widespread local sources because they are proven existing technologies. Local sources of water are obvious - rainwater, local rivers, and lakes. The three "prongs" of a conservation strategy are: 1) improvement of efficiency, 2) elimination of unnecessary use, and 3) substitution of local sources.
Unlike conservation measures, outputs that pollute or degrade the environment mostly do not have direct monetary costs associated with them. Their effects are mostly social costs, like the health effects of poor sewage disposal, or survival issues, like global warming produced by greenhouse gases, which buildings generate more of than any other economic sector. Output reduction currently depends mostly on education and raising awareness. Reduction of by-products that leave the premises is in some cases actually a facet of conservation (improving efficiency by waste reduction). In other cases, the technology produces by-products that are inherent polluters that have historically been vented, burned off, or dumped. In addition, some systems have produced unanticipated, unwanted by-products. Emission reduction and pollution prevention are strategies to reduce the impact of specific outputs on the environment, while overall energy conservation reduces greenhouse gas effects by reducing the burning of fossil fuels.
So far, we have examined building services technologies from an abstract, ideal point of view. First costs and payback periods obviously affect how much improvement will be made and how fast it occurs. But it is clear that while building services technologies used without consideration of sustainability are commonly bad for the environment, better technology can also be the solution to the problem originally created by technology. The two basic strategies are conservation - reducing incoming energy and water requirements - and emission and pollution reduction - reducing undesirable outputs.
Building Technology Improvements
Efficiency is clearly one key to conservation, but evaluating which efficiency measures applied to which technology would do the most good is often difficult. Most building code jurisdictions in the United States have minimum energy conservation standards incorporated into law via either a model energy code or customized regulations. The most commonly cited standard is ASHRAE 90.1, Energy Standard for Buildings Except Low-Rise Residential Buildings. Some states, notably California, have more stringent energy conservation standards. These regulations specify overall performance for the whole building and some portions or systems of buildings and prescribe some requirements for some systems. Existing buildings typically are not required to be retrofitted to meet the regulations. Water consumption is typically not regulated except for plumbing fixture maximum flow rates prescribed by plumbing codes based on federal regulations. Conservation measures that would satisfy the applicable regulatory requirements should be considered the bare minimum.
Although the requirements of codes and regulations are considered merely minimum, they are a good starting point for identifying potential conservation measures. Many performance criteria can simply be increased further for additional reduction in consumption. Other conservation measures might involve completely different systems than those mentioned in the codes. Two good resources for identifying potential improvement measures are the U.S. Green Building Council's LEED rating system and the Green Building Initiative's Green Globes rating system. Both of these organizations have studied the problem of buildings in relation to the environment for many years and have worked out performance criteria for many building systems that can be used to evaluate existing buildings and design new ones. Although both organizations offer third-party certification or verification services - to demonstrate achievement of a certain rating level - participation in the programs is not a prerequisite to using their publications and resources for self-evaluation or design. The rating system publications of both organizations are the most comprehensive checklists of environmental issues relating to buildings available.
|Both LEED and Green Globes organize their criteria by general category: |
LEED-NC Version 2.2
- Sustainable Sites
- Water Efficiency
- Energy & Atmosphere
- Materials & Resources
- Indoor Environmental Quality
- Innovation & Design Process
Green Globes v.1
- Project Management - Policies & Practices
- Resources, Building Materials, & Solid Waste
- Emissions & Effluents
- Indoor Environment
In both systems, the measures in the water and energy categories are almost exclusively devoted to technologies. Green Globes separates emissions and effluents into a separate category, while LEED includes many of the same criteria in other categories. Some of the technologies that address criteria in both systems are described below.
- Upgrading plumbing fixtures in existing construction (new construction is regulated by law in the United States)
- More efficient landscape irrigation technology, such as by drip or other high-efficiency methods
- More efficient cooling towers
- Innovative wastewater technologies
Local Water Sources
- Collected rainwater. Rainwater can be used untreated for all nonpotable uses and, when treated, for potable uses.
- Gray water. Wastewater not containing sewage can be used for landscape irrigation and sewage conveyance.
- Automatic lighting controls, to take advantage of daylighting
- Lighting control zones and occupancy sensors
- Day-night scheduling or setback of HVAC controls
- Thermally zoned HVAC systems
- Direct occupant control of HVAC and lighting
- Hybrid natural/mechanical ventilation, with automatic controls
- "Right-sized" energy-efficient systems of all kinds
- More efficient motors
- Submetering in multiple tenant facilities, to promote accountability
- Advanced monitoring, for information to raise awareness
- Advanced controls to fine-tune systems
- Retrocommissioning of existing HVAC systems (restoration to design parameters)
Local Energy Sources
- On-site photovoltaic, wind, geothermal, and bio-based electricity generation
- Purchasing of "green power" by the building owner
Emission and Pollution Avoidance
- No use of refrigerants that damage ozone layer
- Refrigerant leak detection and alarm
- Low-NOx and low-CO boilers and furnaces
- Interceptors and traps on drains from kitchens, photo finishing facilities, laundries, parking lots and garages, and places where hazardous or toxic materials are used
- Fuel oil tanks with secondary containment and leak detection and alarm
- On-site wastewater treatment (reduces load on municipal facilities)
- Adequate and enhanced ventilation and outdoor air intake
- Direct occupant control of HVAC and lighting
- Advanced HVAC controls
- Outdoor light pollution reduction by means of light fixtures, shading, and controls
- Isolation and venting of spaces involving use of hazardous materials
Source Material Reduction
- Reusable components
- To promote building adaptability, Green Globes gives credits for both avoiding relocating light fixtures and other components and using such components that are easily relocated.
Evaluation of possible conservation measures is analogous to evaluating your family's budget: Water and energy cost money, so first find out how much they cost now. For an existing building, this is pretty easy - about 12 months of utility bills will show you an average year's worth of consumption. For a new building, energy analysis requires more computation but is a well-established discipline. The U.S. Environmental Protection Agency (EPA) also has two relatively easy analysis methods. For existing buildings, the EPA's ENERGY STAR® Portfolio Manager is an online system that compares an existing building to a database of similar buildings and gives the building a relative rating. EPA's Target Finder performs a similar function for new buildings and upgrades to existing buildings, helping establish performance goals on a 1 to 100 scale.
Computing the cost allocated to each system or service is the next step. This will usually involve estimating based on certain assumptions. For instance, the amount of water used by toilets in a residential facility is not usually metered but can be estimated based on available usage studies. On the other hand, the amount of water used by an existing cooling tower could be relatively easy to meter.
If a potential conservation measure involves replacement of equipment or systems, it is probably not necessary to do a whole building energy study. The relative efficiency of the new technology can be compared to the existing (or designed) technology and a consumption reduction calculated. Based on the water or energy unit cost for the facility, the actual operating cost savings can be estimated. Cost increases over the life of the system can be estimated and a "payback" period calculated. For measures to reduce pollution or emissions, the social cost of not doing it may need to be taken into account.
Both the LEED and Green Globes rating systems provide many resources for evaluating potential conservation and pollution/emission avoidance measures. They both direct the reader to expert references in each field and include criteria for calculating how much improvement has occurred. The LEED Rating Systems each have discrete prerequisites and credits. There are currently five rating systems: new construction, existing buildings, core and shell development, commercial interiors, and schools. The building services-related credits are similar in each rating system regardless of occupancy - most of the differences relate to operating procedures for different occupancies. The Green Guide for Health Care is a similar rating system, based on LEED, for hospitals and other healthcare occupancies. The Green Globes rating system is for new construction, with an existing buildings rating system in the pilot stage.
All of these rating systems include many more requirements, including:
- Passive measures for conservation, daylighting, and views
- Good site selection
- Alternative transportation measures
- Reduction of heat island effects
- Commissioning of building services
- Building operations for indoor air quality
- Reused and reusable building fabric and materials
- Materials with low- or no-VOC emissions
- Recycled material content
- Rapidly renewable material content
- Locally and regionally sourced materials
- Sustainably harvested wood products
- Solid waste collection and recycling
- PCB, asbestos, and mercury reduction in existing buildings
- Construction waste management
- Construction indoor air quality procedures
- Indoor chemical and pollutant source control
- Environmental tobacco smoke control
Conservation and Emission/Pollution Reduction Guidelines
International Code Council (ICC)
- International Energy Conservation Code (IEC), 2006. Model code for adoption by local jurisdictions
U.S. Green Building Council
- LEED-EB, version 2 - for Existing Buildings, Upgrades, Operations, and Maintenance
- LEED-NC, version 2.2 - for New Construction and Major Renovations
- LEED-CS, version 2.0 - for Core and Shell Development
- LEED-CI, version 2.0 - for Commercial Interiors
- LEED-K12, version 1.0 - for Schools for New Construction and Major Renovations
Green Building Initiative
- Green Globes, v.1 Rating System, New Construction
- Existing Buildings (pilot program)
Green Guide for Health Care
- Green Guide for Health Care, version 2.2 (pilot program), based on LEED with modifications for healthcare
Design and Upgrade Resources
American Society of Heating, Refrigerating, and Air-Conditioning Engineers
- ASHRAE 90.1, Energy Efficient Design of New Buildings Except Low-Rise Residential Buildings, 2004
- ASHRAE Handbook - Fundamentals, 2005. Chapter on Energy Estimating and Modeling Methods
- ASHRAE Handbook - HVAC Applications, 2003. Chapter on Owning and Operating Costs
Energy Star, joint program of U.S. EPA and Department of Energy
U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy
Susan McClendon (firstname.lastname@example.org) is executive vice president of Building Systems Design Inc. (www.bsdsoftlink.com).
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