Frugal Flow

Mar 1, 2008 12:00 PM, By Richard Nortier

Plumbing systems engineered for high-use environments can reduce water use in restrooms.

The plumbing products most appropriate for a high-end hotel or executive restroom will differ from those most suited for school and university restrooms, where large numbers of boisterous students may charge through the doors all day long. But installing plumbing that can stand up to rough-and-tough student use doesn't have to compromise efforts to save water.

In fact, two plumbing technologies, originally designed to solve problems common in high-use/high-abuse restrooms, also enable schools and universities to use water more efficiently. These plumbing technologies — high-use flush modes for urinal flushometers and monitored control systems — can be used in conjunction with other plumbing products to substantially reduce restroom water use.

High-use flush modes

The high-use flush mode is a built-in option on some electronic urinal flushometers. Its intention is to get the lines of men waiting for urinals to move more quickly when restroom traffic volume is high, especially in large facilities such as auditoriums and stadiums.

Sensor-operated urinal flushometers with high-use flush modes can be set to flush only at pre-determined intervals, instead of after every single user, or to vary the water volume from flush to flush. Either way, these modes can reduce water usage. Urinals that already consume as little as 0.5 gallons per flush for regular operation can use much less water overall when equipped with a high-use flush mode feature.

High-use flush modes come in two basic types. The first, stadium flush, typically flushes once for about every five men in line. The second type is per-cycle reduced-volume flushing. This mode flushes after each user, but the water volume varies with each flush. It may flush with 0.3 gallons for several users in a row, followed by one full-volume, cleansing flush. Then the low-volume cycle restarts.

Monitoring systems

In private restrooms, such as those restricted to staff members or administrators, users typically will be more conscientious about treating restrooms properly. Technologies such as manual dual-flush flushometers make sense in these restrooms; habitual users are more likely to learn how to use these water-efficient devices to their full potential.

Restrooms for students and the general public are a different story. Depending on the facility, these restroom users are more prone to vandalize or misuse plumbing, and they're more apathetic about or less familiar with their surroundings.

In these restrooms, where facility managers can't count on user cooperation, plumbing products and systems that are automatically set to use water more efficiently are the best bet. Sensor-operated, low-consumption flushometers and faucets with 0.5 gallon-per-minute sprayheads are suited especially for high-use restrooms. These water-efficient plumbing products automatically regulate water flow. Plus, there's less chance of breakage that results because users are not turning knobs or pushing handles.

Another technology that some schools are turning to is monitored plumbing-control systems, which better manage plumbing products and water usage. These automated plumbing systems, which keep tabs on and control any or all plumbing components, traditionally have been deployed in prisons and other facilities where security is a priority. If the software-based system shows that one flushometer is being flushed continuously, the administrator immediately can deactivate only that flushometer.

The system also enables preset parameters: Administrators can program the system to automatically lock out additional flushes, for example, after two flushes in a row, or to allow water to flow to showers during limited hours. This type of control keeps users from abusing plumbing products.

When administrators change which plumbing products can operate when, they are saving water — whether or not that's their main intention. Think about how much water would be wasted or the potential flooding that could occur if a single shower was left running over a weekend or if no one witnessed an unattended water closet that repeatedly flushed.

This type of control system has wide-reaching uses in education settings. Remote monitoring and control of one or all sinks, water closets, urinals and showers in a facility make it easy to turn water flow on and off to plumbing products when students pull pranks that could damage plumbing or when they attempt to flush contraband. These controls also help with scheduled or emergency maintenance, or for regulating plumbing in seasonal facilities, such as fieldhouses and residence halls.

Because monitored systems provide views of when and how long each system-connected sink, water closet, urinal or shower is used, they also offer administrators valuable usage information that relates directly to water efficiency. Using these system views, administrators could calculate how much water certain plumbing products use or determine traffic patterns in different sections of a building.

Administrators then would have solid data to make the case for investing in more water-efficient plumbing or to take other water-saving steps.

Nortier is marketing research manager for Sloan Valve Company, Franklin Park, Ill.

0.5
Total gallons of water used in one standard toilet flush.

To flush or not to flush

A recent study compared two high-use flush modes to determine which uses water more efficiently. Results showed that stadium flush uses much less water than reduced-volume flushing when there's a long queue. In fact, the longer the queue, the more water a stadium flush mode will save.

For a queue of 15 users, the reduced-volume flush mode typically would have a 0.5-gpf flush after users 1, 10 and 15; after all other users, there would be a 0.3-gpf flush. The stadium flush mode, on the other hand, would trigger a 0.5-gpf flush after users 5, 10 and 15; there would be no flush after all other users until the queue ended.

The results: The stadium flush mode serving 15 men would use only 1.5 gallons of water, compared to 5.1 gallons total for the reduced-volume flush mode.

Both high-use modes, however, are improvements over a regular flush mode of 0.5 gpf after every user, which totals 7.5 gallons of water for a queue of 15 users. The stadium flush mode would be 80 percent more water efficient than the regular flush mode, and the reduced-volume flush mode would be 32 percent more efficient. The savings would grow even more with new urinal flush valves using only 1 pint of water.

Total gallons used by urinals for a queue of 15 men, by flush mode

USER # IN LINE	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	TOTAL GALLONS USED
Stadium flush					0.5					0.5					0.5	1.5
Reduced-volume flush	0.5	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.3	0.5	0.3	0.3	0.3	0.3	0.5	5.1
Standard flush	0.5	0.5	0.5	0.5	0.5	0.5	0.5	0.5	0.5	0.5	0.5	0.5	0.5	0.5	0.5	7.5
*Gallons used based on standard urinal flush volume of 0.5 gpf. Source: Sloan Valve Company