Page 069 - evaluate the cost-effectiveness of specific conservation strategies.
Source section: Section 4 - Green Building Core Concepts and Application Strategies PDF page: 69 Guide page: 62 OCR quality: high (450 words)
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Some project teams use their sites’ annual precipitation to determine how much water they should use. Clearly, the water balance approach is more achievable for projects that receive more rain and require less irrigation. However, projects around the country are experimenting with this goal. It requires reducing demand by designing sites to minimize or eliminate the need for irrigation and installing plumbing fixtures that either conserve water (such as low-flow lavatories and dual-flush toilets) or eliminate demand entirely (such as waterless urinals and composting toilets). Additionally, captured rainwater and treated graywater can be used instead of potable water for toilet flushing, irrigation, and cooling towers. The value of any particular measure for overall water conservation efforts depends on the end uses in the project. For example, office buildings typically lack extensive laundry and kitchen facilities; water is used for HVAC systems, restrooms, and landscaping. In contrast, kitchen sinks and dishwashers dominate the end use for restaurants. A water end-use profile can help project teams identify the largest users of water and evaluate the cost-effectiveness of specific conservation strategies. An “efficiency first” approach to water conservation can be very effective. First look at ways to use water efficiently and reduce potable water use. Then, consider the use of nonpotable water and alternative sources of water. LEED rewards projects that both reduce demand and reuse water for indoor and outdoor water uses. Indoor use encompasses water for urinals, toilets, showers, kitchen or break room sinks, and other applications typical of occupied buildings. Indoor water use can be reduced by installing water-efficient fittings and fixtures, using nonpotable water for flush functions, and installing submeters to track and log water use trends, check fixture performance, and identify problems. Buildings also use significant amounts of water to support industrial processes and systems, such as cooling towers, boilers, and chillers. These systems provide both heat and cool air and water for building operations. Process water also includes the water used for certain business operations (e.g., washing machines, dishwashers). Commercial building projects can reduce water use by selecting efficient cooling towers, chillers, boilers, and other equipment, and by substituting harvested rainwater and nonpotable water for certain applications. Understanding how water is being used allows teams to identify where they should focus conservation Zz 4 $ fo) efforts. Submeters report how much water is being used by systems and fixtures and alerts managers to leaks 3 or other inefficiencies. Metering the water lost to evaporation during cooling tower operation can provide w . . sdea5 +: . “ye a particularly important information. Facilities may be able to receive credit from the utility company for a I sewer charges if they reduce the amount of water entering the sewer system. re | Ww SI =] oO w a Ww .e) Zz fe) O Ww a fe) oO a w Ww ad 62