Flushing Out Solutions
Jul 1, 1997 12:00 PM, Jose Baz
The Federal Energy Act and other water-conservation trends are forcing educational administrators to demand better performance from washroom equipment, which is pushing plumbing-fixture manufacturers to create products that achieve water savings.
One new technology arising from this demand--pressure-assist, along with continued improvements in gravity-type toilets--offers institutions the best chance of reaching true water conservation without sacrificing performance. However, this new technology did not come about without its share of problems.
Trial and error Once fixture manufacturers decided to take a serious look at water consumption levels and water conservation, modifications to the existing gravity product were made. What resulted, however, has contributed more to the negative impressions regarding 1.6 gallons per flush (GPF) low-consumption toilets than any other factor.
To achieve low-consumption gravity performance, manufacturers decreased the size of the trap and other openings. This resulted in a stronger siphonic action to withdraw the waste. Still, institutions began dealing with:
*Students having to double flush. *Students having to hold down the handle longer to clear the bowl. *Toilets clogging more often. *Toilets having to be cleaned more often.
It was about this time that pressure-assist technology came into the market. From early efforts to utilize a gravity-type bowl with the pressure vessel, it was realized that a new bowl design was essential to the success of the pressure type. The eventual design of a pressure bowl is the main reason why pressure-type technologies do not work when retrofitting existing toilets; they require specific design elements to accommodate the strong forces from the pressure--elements not built into the gravity bowl.
Creating the solution Pressure-assist technology is responsible for delivering the performance that institutions have come to expect from toilets. Low-flush toilets work as well as regular toilets. The satisfaction with these pressure toilets is impressive, and that satisfaction relates directly to the frequency of problems encountered with the new toilets compared to older gravity models.
When considering retrofitting your washroom facilities with pressure-assist technology, ask the following questions: *Should I use a pressure-assisted system? There are distinct situations where one technology will be preferred over the other, and it often depends on whether it is new construction or renovation. Evaluate the water supply, pressure levels and piping. Determine how long the system has been installed and if there could be bacteria buildup or corrosion in the pipe flow. These findings will determine which technology fits best for the installation.
*How much water is really saved? If a toilet is more than 15 years old, it uses between 5 and 7.5 GPF. The older the toilet, the more water it probably uses. If a toilet was manufactured after 1980, it uses 3.5 GPF, which is the current national standard and not considered a low-flush toilet.
Commercial and institutional applications require especially close evaluation. More states are mandating the use of pressure technology in commercial and institutional structures, and for good reason--especially in schools, children tend to throw just about anything in the toilet. The pressure option allows a facilities manager to deal with the unknown in a positive, preventive way.
It also is important to evaluate the user. For example, consider adults' and children's needs, as well as how much usage the toilet will receive and the venting required.
If one or more of the following conditions exist, consider pressure technology as a low-flush 1.6 GPF solution:
*Pressure is at least 20 psi. *Oversized drains. *Poor venting. *Poorly pitched drain lines. *Users have had previous problems with the toilet. *State regulations on commercial/institutional installation.
San Simeon, Calif., is a good example illustrating some of the differences in pressure technologies and how they relate to low flushing. Because of the now-infamous western drought of 1986, the effects on the city's water supplies grew more severe. Waste-water-treatment-plant demand was reaching 100-percent capacity during the peak season; the situation intensified despite a public awareness. In 1989, with levels becoming critical, a new action plan had to be implemented.
The choices were rather grim--new, supplemental water sources; additional waste treatment capacity; and more rationing. The alternative that town officials finally settled on was replacing all toilets with low-consumption ones. After tests and evaluation of the technologies, pressure-assist was selected because of the commercial successes it had experienced. Also, officials performed their own evaluation tests, settling on the pressure option.
Once pressure-assist low-consumption toilets were installed, water consumption in the town was reduced by 39 percent, and bowl stoppages were reduced by 95 percent compared to the older 3.5 GPF toilets. Besides preserving the economic vitality of the community, the low-consumption systems eliminated all double flushing.
