Medical Construction & Design

JAN-FEB 2016

Medical Construction & Design (MCD) is the industry's leading source for news and information and reaches all disciplines involved in the healthcare construction and design process.

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+ It is recommended to replace storage tanks with steam-fi red instantaneous water heaters. These eliminate the need to store water that might otherwise become stagnant. Surveying for dead leg pipes identifi es insuf cient water fl ow. Dead leg pipes can be dif cult to fi nd and take a signifi cant amount of survey time. Pipes may have been capped during a renovation, capped for future extension or terminated improperly. Using fl ow restrictors instead of aerators in plumbing fi x- tures is also helpful. Flow restrictors produce a stream of water rather than a mist, minimizing the potential for aspiration. To keep water in motion, water pumps should run continuously. Exclude them from energy-conservation programs because the benefi t of preventing stagnation outweighs the energy savings. A self-draining pipe between the showerhead and control valve eliminates areas of insuf cient fl ow to prevent stagnation. Storage tank maintenance M aintaining storage tanks is a critical component of Legionella prevention. Hospitals must inspect and clean storage tanks annually. It is critical to verify that storage tank lids are secure to prevent the infi ltration of foreign materials. These tanks should also have the drainage valve at the lowest point of the tank to prevent stagnation. To avoid pockets of unregulated temperature in a tank, the tank heating element should also be as low as possible. Other maintenance tasks include fl ushing safety showers and eye wash stations at least monthly. Testing E nvironmental culturing is a proactive way to stay ahead of Legionella outbreaks. Test samples for Legionella typically come from faucets, sink outlets, taps, fi lters and showerheads. These are disassembled, swabbed and scraped to obtain Legionella-bearing bacteria. A study in the Environmental Protection Agency's Legionella: Human Health Criteria Document outlined a methodology with thresholds for maintenance practices. For Legionella concentrations that exceed 1,000 organisms/mL in cooling towers or 100/mL in potable water, the authors recommend immediate disinfection of equipment. The Centers for Disease Control outlines another approach in their Guidelines for Nosocomial Pneumonia. For hospitals without prior identifi ed cases, the CDC recommends two primary prevention measures. The fi rst is routine culturing of the potable water system, with diagnostic laboratory testing when more than 30 percent of environmental samples test positive for Legionella. The second is the use of diagnostic laboratory tests for high-risk patients with nosocomial pneumonia, with routine maintenance of potable water supplies. It requires an environmental investigation once one defi nite or two possible cases of Legionnaires' disease have been identifi ed. Many governing agencies have recognized the growing risk of Legionella. In some states, the Department of Health issues hospital guidelines for detecting and preventing the spread of the bacteria. Other jurisdictions require annual testing. Training hospital maintenance personnel is another good practice. Keep good records of all cleaning practices. These should include fl ushing, fi lter changes, chemical treatments and cleaning. Keep test results for reference. Performing a routine environmental culture of the hospital water supply has proven an important strategy in prevention. Getting started A water quality engineer tests for the presence of Legionella and can treat non-potable systems. A plumbing engineer identifi es the infrastructural elements that foster Legionella activity in potable and non-potable systems. Although it is dif cult to treat every possible area where Legionella can grow, using available preventive measures can greatly reduce risk. Plumbing engineers perform an as-built survey to identify possible Legionella growth sources. With the many renovations that occur in medical centers, most have dead leg pipes and in- suf ciently distributed recirculation loops. With this informa- tion, plumbing engineers recommend controls to deter future bacterial cultivation. Adequate control is costly and requires considerable attention to detail, and is best implemented by qualifi ed engineers. Any prevention measures should comply with the latest guidelines, such as ASHRAE Guideline 188-2015, Legionellosis: Risk Management for Building Water Systems. Don't be the next facility in the news. Rely on an engineer- ing partner to assist in developing a prevention, mitigation and treatment plan. Charlie Hall, P.E., QCxP, is the director of engineering at FreemanWhite. He can be reached at charlie@freemanwhite.com. MCDM AG.COM | JA N UA RY/ F EBRUA RY 2016 | Medical Construction & Design 45

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