ASHRAE Journal - June 2010 - S17

Section 6:

Plumbing Fixture Water Closets (Toilets) • Flushometer Valve Type • Flushometer Valve Type • Tank-Type

Maximum Volume Single Flush – 1.28 gal (4.8 L) Effective Dual Flush – 1.28 gal (4.8 L) Single Flush – 1.28 gal (4.8 L) and WaterSense-Certified Effective Dual Flush – 1.28 gal (4.8 L) and WaterSense-Certified 0.5 gal (1.9 L) 0.5 gpm (1.9 L/min) 0.25 gal (1.0 L) per Metering Cycle 1.5 gpm (5.7 L/min) and WaterSense-Certified 2.2 gpm (8.3 L/min)

Water Use Efficiency
The standard provides significant water savings over current codes and addresses the unnecessary water waste that takes place in buildings and on landscape, and establishes significant yet attainable limits to monitor and manage water consumption.

Urinals Faucets • Public Lavatory • Public Metering Self-Closing • Residential Bathroom Lavatory Sink • Residential Kitchen Showerheads

• Residential 2.0 gpm (7.6 L/min) • Residential Shower Compar tment All Shower Outlets – 2.0 gpm (7.6 L/min) (Stall) in Dwelling Units and Guestrooms Table 1 Plumbing fixtures and fittings requirements.

Mandatory Site Water Use Reduction

Landscape design has a huge impact on water use. To conserve resources, municipalities and other local water utilities have started to impose restrictions on the use of domestic treated (tap or potable) water for lawns and other landscape areas. From an economic standpoint, the water that is available is becoming more expensive to water users than in the past. When extensive landscaping is in turfgrass, water needs are the highest. Standard 189.1 requires that at least 60% of the improved landscape of a project be in biodiversity plantings of native and adapted plants, limiting the allowed areas for turfgrass. These are plants that reliably grow well in a given habitat with minimal attention from humans in the form of winter protection, pest protection, water irrigation, or fertilization once root systems are established in the soil. Adapted plants are considered to be low maintenance but not invasive. Have you ever noticed sprinklers watering grass when it is raining? The required use of smart controllers for
June 2010

irrigation that use evapotranspiration, soil types, weather data or on-site rain or moisture sensors can fix this problem. They will shut down the system when there is enough water available to the root zone of the plants. Another requirement to reduce water use in landscaping is through use of zoning the irrigation system. By placing plants in groups near each other that require similar moisture levels, they can be similarly irrigated, a practice known as hydrozoning, since differing amounts of water are required by trees, shrubs and grass.
Mandatory Building Water Use Reduction

The U.S. Green Building Council’s LEED rating system encourages use of plumbing fixtures that are more efficient than the EPAct 1992 code requirements and, in some cases, are WaterSense certified. These high-efficiency goals are part of the mandatory requirements of Standard 189.1 (Table 1). Appliances must be ENERGY STAR rated. The standard also contains water efficiency requirements for HVAC equipment. “Once-through” cooling systems

are prohibited. In these prohibited systems, water is withdrawn directly from the source water body, diverted through a condenser where it absorbs heat, and then discharged back into the source water body at elevated temperatures. Because once-through cooling systems do not recirculate the cooling water, they can require thousands of gallons of water per day. Even though these systems can be simple and low-cost, the environmental impact of drawing water from wells, lakes, streams, rivers or even municipal water systems is high. High discharge temperatures back into the environment can have damaging impacts, such as increased algae growth, depleted oxygen levels and elimination of microorganisms that feed fish. Condensate from steam systems and large air-conditioning units (larger than 65,000 Btu/h [19 000 W]) must be recovered and reused. Air handler condensate recovery systems can reroute the collected condensate from the AHUs to cooling towers to be used as makeup water, reducing the amount of potable water needed for cooling
S17

ASHRAE Journal’s Guide to Standard 189.1

ASHRAE Journal - June 2010

Table of Contents for the Digital Edition of ASHRAE Journal - June 2010