58/Plumbing Engineer August 2021
parts/million (mg/L), but the estimated time it takes for free chlorine to diminish below recommended levels in stagnant systems is 1 1/2 days in galvanized piping sys- tems, 4 1/2 days in unlined cast iron systems, and 10 to 14 days in lined systems. Refreshing water supplies takes energy and must be programmable to occur on a regular basis. Today's sen- sor-operated fittings and fixtures can support that func- tion and limit the potential for stagnation. They also can use programmable flushes to clear undesirable fluids and combat odors in drains, limit dwell times and resultant metals contamination, and ensure water is maintained in p-traps over time. When considering touch-free units, the questions you should ask yourself and your team are: Does the touch-free device being specified include the ability to set a regular line-flush in order to bring residual disinfectant into the distribution system to avoid stagnation? Is the feature flexible enough to permit adjustment of both the frequency and duration of the line flush in order to meet the needs of a particular facility? To save time and minimize customer interruptions, can the settings of the devices be done wirelessly using a device similar to a smartphone? Are the devices set up to deliver data such as water usage and verification of line flushes? All these are features available in today's sensor- operated devices were unavailable just a few years ago. They can offer key advantages in infection-control ini- tiatives that are unavailable with manual devices. You also should ask if it's possible to upgrade older existing sensor-operated devices to include these features. Key Variables and Features Here are some key items to consider: Does the touch-free device come with the line flush features described previously? Verify the mountings of the products being upgraded. Faucets can be deck-mounted or wall-mounted using either a single hole, a 4-inch center set, or an 8-inch center set. Mountings for matching faucets and soap dis- pensers should be verified. Existing flushometers can be upgraded with side- or top-mounted retrofit kits. Verify the basin type, size depth, faucet-mounting setback and the location of mirrors and shelves. Some standards require a specific faucet height or flow in rela- tion to the drain position. Smaller basins require lower faucets to avoid splashing, while scrub sinks might require gooseneck faucets with surgical bend spouts to ensure optimal use. Confirm temperature-mixing requirements. The fau- cets used may vary based on a pre-tempered supply, on separate hot and cold lines and on an ASSE 1070-com- pliant thermostatic mixing device. Consider the use of an optional side-mixer to give users temperature control. Consider the available room for the faucet controls. Verify if enough room is available under the sink deck to place a control module. If not, an above-deck faucet with all key components contained in the spout is an option to provide the same function. Match toilet and urinal flush volumes with the appropriate flushometer settings. A 5.0 gpf (19 lpf) toilet installed prior to the Energy Policy Act of 1992 may have pressure issues operating with today's 1.28 gpf (4.8 lpf) flushometers. This applies equally to manual and sensor-operated units. Is the facility hard-wired to supply power to all new fittings and fixtures, or will batteries be required? Recall from the previous section that hard-wired products are more sustainable and require less service over time than battery-powered products but may need a backup battery for use during a power outage. If batteries are the only option, the use of a hybrid power-generating type such as solar cells or turbines will extend battery life. The application of hybrid solutions should consider the frequency of use for the fixtures in the space as well as the incoming water quality. The intent of this article is to advise facility owners and managers of automatic sensor technology develop- ments, identify the potential advantages these fixtures can offer, and reduce confusion regarding best practices application of this technology. In an upcoming article, we'll expand into options and best practices specifically for educational institutions. The availability of American Rescue Plan stimulus fund- ing through September 2023 has led many schools to upgrade from manual to touch-free restroom equipment as part of their post-pandemic return to "normal." In that upcoming installment, we'll focus directly upon the need and considerations for that sector. O Lowell Manalo is the lead plumbing and fire protec- tion designer with SmithGroup's Phoenix office. He is a member of ASPE and has 20 years of experience design- ing plumbing systems for various building types. Andrew Warnes is the manager of technical training for Sloan. His areas of expertise include bacteria and virus exclusion using artificial membrane substrates and sensor faucet design. He is the former international director of the Water Quality Association and negotiator of water treatment standards between the United States and the European Union.
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