56/Plumbing Engineer August 2021
but on a much smaller scale. The movement of water through the unit spins a turbine that generates electricity to supplement battery usage. In facilities with high usage, the advantage of turbines is that the more often these devices are used, the more energy they generate and the more battery power they can supplement. Because the turbine is immersed within the incoming water supply, it is often recommended that turbines be specified only in locations that have a known, consistent, good-quality water supply. Most municipally supplied water systems in the United States and Canada will meet this criterion. Both solar and turbine hybrid power-generating tech- nologies have the potential to double the life of batter- ies, though this can vary due to factors such as usage patterns, water and ambient temperatures, water quality and other variables. When there is no choice and no hard-wired connection is available, the use of batteries in conjunction with hybrid power supplies is more sus- tainable and more cost-effective in the long run than just batteries alone. Touch-Free Sensor-Operated Fittings and Waterborne Pathogen Risk The drive toward lower water consumption in fittings and fixtures (both manual and sensor) had a significant environmental impact relative to water savings, but at the same time also led to concerns about water stagna- tion in distribution lines and drain carry issues. Older facilities designed when the average faucet flow was 2.2 gallons/minute (8.3 liters/minute) and the typical toilet flush volume was 5.0 gallons/flush (19 liters/flush) had much larger piping sizing to match the increased water consumption. As the facility converts to today's 0.5 gpm (1.9 lpm) faucet flows, 1.28 gpf (4.8 lpf) toilet flush volumes, and 0.125 gpf (0.47 lpf) urinal flushes, the larger piping becomes a potential liability due to slower water veloci- ties and longer residence time for water in the pipe. Water conservation and water efficiency in commer- cial restrooms and in health-care facilities have been encouraged for over a decade. With these efforts becom- ing more commonplace and successful, new technolo- gies should be considered for the overall water health of the building. Stagnant water is a real problem, but these technologies offer real solutions. The risk of water stagnation due to lower flows (or less frequent use) involves the reduction in residual disinfectant (chlorine, for example) over time. The EPA recommends a free chlorine level of between 1.0 and 4.0
Touchless
Photo: SmithGroup
Previous Page