Going Green is Building
There is a growing focus on controlling energy and monthly costs in homes and commercial buildings. Now, there is new emphasis on controlling water usage. In drier parts of the country, such as the Southwest and parts of the Pacific Northwest, freshwater sources are rapidly diminishing. This dilemma has influenced the building and design industries to create innovative methods of water conservation or so called ”water-cycle management”.
As costs for fresh water continue to escalate, implementing water efficient designs reduces the overall need for water and will save money and conserve resources for years to come.
Today, there are no national regulations, plumbing, or electrical codes requiring buildings to be highly energy or water efficient. Water conservation and water re-use are still in its infancy in the U.S., possibly due to the regulatory complexity.
Regulations vary greatly from city-to-city, county-to-county, and state-to-state. Arizona is very progressive in gray water re-use, having published 13 best practices that simplify the permit process. So far, no other state has published a similar guide for rainwater harvesting. Hopefully states will become more proactive in saving water and eventually push for a national standard in this area
The U.S. Green Building Council, founded in 1998 and working to promote buildings that are environmentally responsible, is starting to address the regulation and evaluation gap, and has established the LEED (Leadership in Energy and Environmental Design) ranking system.
LEED evaluates commercial buildings and provides a verifiable means of demonstrating that a building is “green”. Under the LEED certification program, there are four classification levels or ratings: Certified, Silver, Gold, and Platinum. The levels are based on points awarded for the design, construction, and operation of a building. The Certified level requires a minimum of 26 points; Silver requires 33 points; Gold is 39 points; and Platinum requires 52 points out of the 69 total possible points.
Points are awarded for sustainable sites, energy efficiency, material and resources efficiency, environmental quality, and more.
Water usage is also addressed, though there are currently only five points available for water efficiency. Water efficiency within the building can gain two possible points, two points are available for landscape efficiency, and the final point is for overall wastewater reduction.
For a builder, reducing water usage within a building can be a quick and easy way to obtain LEED credits, and can be achieved with little additional cost over standard plumbing fixtures and fittings.
Inside an office building, points for water conservation are awarded for reducing water use by 20 percent (worth 1 LEED point) and 30 percent (worth 2 LEED points).
Water efficiency measures inside commercial buildings can easily reduce water usage by 30 percent or more. In a typical 100,000 square-foot (9,290 square meter) office building, low-flow fixtures coupled with sensors and automatic controls can save a minimum of one million gallons of fresh, clean drinking water per year, based on 650 building occupants, each using an average of 20 gallons (90.0 liters) per day. The majority of this usage, in an ordinary office setting, is in toilets and sinks.
Currently, new, standard toilets use 1.6 gallons (7.2 liters) per flush (gpf), as compared to 3 gpf (13.6 liters) in older toilets. Dual-flush toilets also conserve water by having a much lower water usage for a half flush (no solids) vs. a full flush (solids). These new fixtures use less than the standard 1.6 gpf (7.2 liters) and are now widely available. They are even starting to show up in homes.
The new urinals consume only 1.0 gpf (4.5 liters). Design strategies using 0.5 gpf (2.2 liters) urinals, as well as water-free urinals, can even further maximize water savings. The use of nonwater-supplied urinals can save up to 1 gpf with each use.
For sinks, a 1.5 gallon (6.8 liters) per minute (gpm) aerator can be installed instead of the standard 2.2 gpm (10 liters) aerator. Additional water conservation can be achieved by installing automatic faucets, which save a tremendous amount of water by operating only when a person’s hands are within the activation range of the faucet.
In a recent study, bathrooms equipped with automatic faucets saved more than 30 percent compared to a traditional manual fixture.
Using low-usage fixtures can also overlap with other LEED categories. Knowing local products and understanding all LEED criteria can maximize point-earning potential for any given building. For example, the same low-flow urinals which contribute to water efficiency could be manufactured from recycled content, and be regionally manufactured (within a 500 mile (804 kilometers) radius of the project site), both of which contribute additional points.
Moving to the outside of the building, one of the largest areas of water use is in watering grass, which consumes an extremely large amount of fresh, drinkable water. Modern landscape design can significantly reduce the amount of water required for irrigation. Drip irrigation, timed irrigation (preferably watering at twilight so that water does not evaporate in the day’s heat), and low water-use plants are easy options that come to mind.
Better yet, the design of the building can include water re-use. The two most common methods of water re-use are gray water irrigation and rainwater harvesting.
For gray water use, a second plumbing system must be installed in a building, which receives the used water from the sinks, bathtubs, and showers and treats it to remove soaps, greases, bacteria, and other waste items before recycling it for irrigation.
Rainwater harvesting is another option that qualifies for a full point under the LEED process. Although rainwater harvesting requires onsite storage, which can be expensive to install, the system reduces water use for years to come with little maintenance and can be easily used for irrigation with little to no treatment.
The objective of the above measures is to reduce the amount of fresh, potable water use for irrigation by at least 50 percent (two LEED points). The two above methods when used together with planting low-water use native plants go a long way to meeting this objective.
The final category for obtaining water conservation points is in wastewater reduction. This category, of course, is directly tied to the previous categories. Less water used means less wastewater to be treated and released into the sewer system for treatment at the local wastewater plant (i.e. reducing the need to raise taxes to build new treatment plants).
The wastewater discharge must be reduced by 50 percent to receive the one point assigned to this category. The other option is to treat 100 percent of the wastewater on-site to a tertiary level. This means at the end of the treatment process, the water can be safely released directly into a local stream or river.
One of beauties of the LEED program is that it allows industrious consumers, builders, and architects to come up with innovative ways of conserving water and reducing wastewater. It is simply a matter of figuring out the best and most efficient way of saving water for a given home or building.
With over 23,000 accredited LEED professionals and 3,700 registered projects underway as of mid-2006, it is obvious that Green Building has captured the imagination of both providers and consumers. Even the government is coming on board: the federal government and some states are starting to provide incentives for building green.
James Wernicke PE and LEED AP, President-Elect of the New Mexico Chapter of the the Green Building Council agrees, saying, “LEED is helping change how builders and architects think about buildings.” He adds, “LEED will soon expand to residential homes and hopefully have the same impact in this market as it is in the commercial building market and eventually building sustainable buildings will be the norm rather than the exception”.
While LEED currently covers only commercial buildings, by the end of 2007, a similar certification program will be in place for homes, LEED-H. The LEED program and programs like it will help drive more sustainable building practices and lead to increased interest in rainwater harvesting and water re-use. With this increased awareness will come more innovative products, lower costs, and wider use.
Find out more about LEED below and get involved in your local community to promote this and other sustainable building practices.