Building Management Hawaii August/September - (Page 33)

Preventing Backflow Near disasters in Hawaii underscore the importance of preventing non-potable materials from entering a public water supply By Paula Bender M ost of us take for granted that the water we use in hospitals, commercial kitchens, office buildings, hotels, industrial facilities, homes and schools is safe. The reality is that our water supply quality depends on how diligently we monitor and maintain our water system equipment and how careful we are with our water system practices. Managers and engineers at Hawaii's residential and commercial buildings and facilities are responsible for not only making sure that building toilets flush and the plumbing stays plumbed, but also that sinks and water fountains flow clear and steamers, coolers and chillers do their jobs. Should a backflow of water occur at your building, it could seriously compromise the health of anyone who comes in contact with it. Backflow is the reversal of flow of non-potable water or other substances through a cross-connection and into the piping of a public water system or consumer's potable water system. According to the Hawaii chapter of the American Backflow Prevention Association, there have been a number of incidents in the Islands in which water systems were compromised by backflow. Fortunately none resulted in disastrous consequences, but each makes the case for due diligence and certification. Let's also not forget the cost of bad press for any given property, which could result in a loss of revenue thanks to one incident that leaves a black mark on your building's reputation. The following are examples of local occurrences over the last two decades that could have easily turned into health and public relations nightmares: * Yellow water noted in a bar sink, caused by the chemically treated airconditioning water (containing the carcinogen chromate) backflowing into the domestic water system. * The discovery of coliform and fecal matter in the domestic water system at one of our airports, caused by a cross-connection between the potable and non-potable water systems. * Red water at a shopping center restaurant, caused when a contractor added a chemical to the center's air conditioning system that had no backflow assembly. * Deodorizer in a hotel's trash chute that backflowed into its domestic water supply. The Honolulu Board of Water Supply requires that building backflow prevention assemblies be tested once a year by a certified tester and that a building's entire backflow system be certified every three years. * Soapy water backflowed into the domestic water system at a carwash, caused by backpressure. A backflow preventer at work in Hawaii Kai. * Discolored water in homes near a coffee processing plant, where the bean washer had used domestic water for priming. So what can you do to help ensure the safety of water at your building? Routinely inspect, clean and maintain your backflow system. This will decrease the likelihood that backflow will occur, plus extend the life of your system and keep fuel and insurance costs under control. Identifying possible compromises in your water system is vital to preventing the spread of germs and potentially fatal diseases. You should also obtain a backflow preventer, which is a mechanism that prevents backflow. The basic means of preventing backflow is an air gap, which is a vertical and physical separation between the end of a water supply outlet and the flood-level rim of a receiving vessel. Together they either eliminate a cross-connection or provide a barrier to backflow. The principal types of mechanical backflow preventers are the reduced-pressure principle assembly, the pressure vacuum breaker assembly and the double check valve assembly. A secondary type of mechanical backflow preventer is the residential dual check valve. On average, backflow Continued on page 36 www.buildingmanagementhawaii.com BMH August-September 2014 33 boileRs & backflow * Blue water in a state office building from the air-conditioning system, which backflowed into the domestic water system. The cross-connection wasn't correctly protected and an unapproved metal-on-metal swing check was in place. http://www.buildingmanagementhawaii.com

Table of Contents for the Digital Edition of Building Management Hawaii August/September

Roofing Warranties: Read Them
Heeding Pacific Cyclone Warnings
Eco-friendly Metal Roofing
Cool Roofing Technology
When Good Pipes Go Bad
Why Cast Iron Pipes Fail
Is Your Sewer Squeaky Clean?
Water Heaters Versus Boilers
Preventing Backflow
Safeguarding Your Building’s Water
Safeguarding Your Building’s Water
Why Regular HVAC Inspections Matter
Why Regular HVAC Inspections Matter
Industry News
Industry News
On Site: A Well-Run Association
On Site: A Well-Run Association

Building Management Hawaii August/September

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