Water Ways
Jun 1, 2007 12:00 PM, By Peter Jahrling
By using products such as no-water urinals, schools and universities can help ease the environmental burden by reducing water consumption. Photo courtesy of Sloan Valve Company
In many communities, schools are among the largest facilities and house the highest concentrations of daytime population. They create a huge demand for water. Even in regions with abundant water supplies, an increase in demand stresses local capacity, and water becomes more expensive.
However, with the help of innovative products that reduce water consumption, schools can have less impact on local environments.
Technology advancements
New technologies that improve performance and reduce water consumption are available for education institutions. For instance, ultra-low-consumption products — and in some cases, zero-consumption fixtures — will become the standard. Industry stakeholders — building owners, operators, municipal water districts, construction associations and manufacturers — are helping develop water-efficiency standards that are feasible at local, state and federal levels.
One new conservation effort is product labeling that identifies both performance and flush volume. On the federal level, the Environmental Protection Agency's (EPA) WaterSense water-efficiency labeling program, which is comparable to the ENERGY STAR program, has established voluntary specification criteria for a high-efficiency toilet (HET). The program includes a standard to ensure optimal performance in addition to maximum consumption levels based on Uniform North American Requirements (UNAR), which includes a soybean mixed-media extraction test.
As defined, an HET fixture has an effective flush volume that does not exceed 1.28 gpf/4.8 Lpf. Further, for fixtures to qualify for the product-labeling program, a performance standard requires a minimum extraction of 350 grams of soybean media. The fixtures also must meet applicable sections of ASME A112.19.2-2003, A112.19.5-2005 and A112.19.14-2001.
The labeling program is a residential program, but these high standards are an excellent benchmark and ultimately may be applied to commercial fixtures used for school applications.
Initial cost vs. life-cycle cost
Green building strategies can reduce the average operating cost of a building by 8 to 9 percent, says Harvey M. Bernstein, vice president of Industry Analytics, Alliances & Strategic Initiatives for McGraw-Hill Construction. Green buildings reduce water consumption by up to 30 percent, and cut overall annual utility costs by 20 to 40 percent for new facilities and 20 to 30 percent for renovations, he says.
With the average age of U.S. schools reaching 40 years, and continued growth in K-12 and college construction projected, the education sector can be an example to teach the rest of the construction industry about the benefits of green building.
The building industry is shortchanging itself by emphasizing initial cost more than life-cycle cost, which is the most important factor to education institutions. Manual faucets, for example, will be “a cheaper quote” when trying to secure a contract. However, specifying no-touch, sensor-operated faucets with 0.5-gpm aerators is the more fiscally conservative choice over the life of the building.
Water conservation and decreased sewage rates enable electronic faucets to close the cost gap on their manual counterparts in just a short time. No-touch faucets are designed to operate for a preset amount of time when a user's hands are in the “active area” that triggers the sensor to allow water flow, and also use significantly less water than manual units.
Using LEED for water conservation
The U.S. Green Building Council's LEED Green Building Rating System establishes “best practice” criteria for water and energy usage that can be applied to any type of construction, even if certification is not the goal. The Water Use Reduction section of LEED-NC identifies a baseline for water use and awards one or two credits for surpassing requirements, in aggregate by 20 percent or 30 percent, respectively, beyond the Energy Policy Act of 1992 fixture performance requirements (see Chart 1 above).
The LEED program shows the importance of establishing a baseline calculation for comparison to a design case scenario (see sidebar, p. 36).
Using this method, school districts can consider “what if” scenarios using simple calculations, with usage factors taken into consideration.
Smart design
Unlike previous generations, new water-conserving products have had extensive field evaluations, which are invaluable for restroom designs. This “in-the-field” experience should reduce any anxiety that may have been formed from experiences with previous generations of low-flow toilets.
For example, no-water urinals have been in use for the past 15 years throughout the world. Half-gallon urinals have been available for the past 18 years. Fractional flush urinals, also called high-efficiency urinals (HEU), have been around for decades. For water closets, dual-flush technology has been available for more than 10 years, and 1.0-gallon pressure-assist units have been available for more than six years.
As potable water and sewer costs escalate — averaging about $4 per 1,000 gallons across the United States, according to the U.S. Department of Energy — water-efficient designs that reduce consumption will minimize operating costs at education facilities for years to come.
To truly appreciate the impact of water efficiency, consider the unique requirements of schools and their massive water draw. Down the line, that water becomes sewage and then returns to municipal water treatment plants to make the circuit again. By incorporating fixtures that promote sustainability and improve hygiene, schools and universities can help ease the environmental burden by dramatically reducing water consumption — and ultimately operating costs.
Jahrling is the director of design engineering for Sloan Valve Company, Franklin Park, Ill.
15
Number of years that no-water urinals have been in use throughout the world.
Saving with no-water urinals
Forsyth County (Ga.) School District engineer George Petty was faced with a weekly bill of $7,500 for pumping septic fields at a single location. He decided that enough was enough.
“South Forsyth High School was on a septic system, and we were having trouble because the field could not take the liquid,” says Petty. “We were pumping three times a week, 10,000 gallons each time at $0.25 a gallon.”
Petty decided that a wholesale retrofit of the school's “regular” urinals with no-water models was the best way to address the situation.
“We changed out all of the urinals in the South Forsyth High School — 50 in total,” he says.
Like traditional urinals, no-water models connect to a drain line to transport waste to the main sewer, but only after it travels through a cartridge that acts as a funnel, allowing liquid from the bowl to flow into the filtering cartridge that holds a biodegradable sealant liquid.
“We have ‘low-flow everything’ — faucets with 0.5 gallon-per-minute aerators, and of course, the waterfree urinals,” says Petty. “We're looking to save water wherever we can.”
To keep pace with the population growth in the Atlanta area, the district is building three schools. “Those buildings also will have waterfree urinals,” says Petty. “In fact, waterfree urinals are now specified in all of our construction documents. They are the accepted standard.”
| Fixture | Flow Req. |
|---|---|
| Water closets | 1.6 gpf |
| Urinals | 1.0 gpf |
| Showerheads | 2.5 gpm |
| Faucets | 2.5 gpm |
| Replacement aerators | 2.5 gpm |
| Metering faucets | 0.25 gal/cycle |
| NOTE: Flowing water pressure of 80 psi | |
Apples to apples
To create the baseline, a spreadsheet can be used to list each water-using fixture in the facility, as well as the frequency-of-use data. This data includes daily uses by males and females, the duration of use and the water-volume use.
| Daily uses | Fixture type | Duration (flushes); faucets shown in minutes | Flow rate (gpf); faucets shown in gpm | Water Use (gallons) |
|---|---|---|---|---|
| 50 | Men's water closets | 1 | 1.6 | 80.00 |
| 150 | Women's water closets | 1 | 1.6 | 240.00 |
| 100 | Men's urinals | 1 | 1.0 | 100.00 |
| 300 | Conventional sinks with faucets | 0.25 | 2.5 | 187.50 |
| Daily total | 607.50 | |||
| Annual work days | 260 | |||
| Total annual volume (gallons) | 157,950 | |||
| Assumptions: Males use urinals twice per day, closets once per day; females use closets three times per day. Both males and females use faucets three times per day. | ||||
To calculate the design case, the number of building occupants, the number of workdays, and the frequency data must remain the same. However, assume the following:
No-water urinals will be used.
0.8-gpf pressure-assist water closets will be used.
Electronic faucets with low-flow aerators (0.5 gpm) will be used. Plus, the electronics have been factored as reducing sink duration by 20 percent (to 12 seconds).
The calculations shown in the design case below use the above fixture types and show a 69 percent reduction in annual water use for the building — far greater than the 30 percent reduction required for the LEED-NC credit. In fact, Water Efficiency Credits 3.1 and 3.2 are achieved cumulatively.
| Daily uses | Fixture typ | Duration (flushes); faucets shown in minutes | Flow rate (gpf); faucets shown in gpm | Water Use (gallons) |
|---|---|---|---|---|
| 50 | Men's water closets (ultra-low-flow) | 1 | 0.8 | 40.00 |
| 150 | Women's water closets (ultra-low-flow) | 1 | 0.8 | 120.00 |
| 100 | Men's urinals (no-water) | 1 | - | - |
| 300 | Conventional sinks with faucets | 0.2 | 0.5 | 30.00 |
| Daily total | 190.00 | |||
| Annual work days | 260 | |||
| Total annual volume (gallons) | 49,400 | |||
| Assumptions: Males use urinals twice per day, closets once per day; females use closets three times per day. Both males and females use faucets three times per day. | ||||
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