What is backflow and how does it occur?
Backflow is the undesirable reversal of flow of non-potable water or liquids into the potable public water system through back pressure backflow or back siphon-age. Back pressure backflow occurs when a higher system pressure (i.e. from a boiler or chilled water make-up system) comes in contact with a potable water system with lower pressure. This differential will cause a cross connection where non-potable water used for mechanical systems can affect the potable drinking water. Back siphon-age occurs like back pressure occurs, across a pressure differential. However, in this case, the non-potable system being siphoned into a potable water system is of a lower pressure. This often occurs in irrigation systems where chemicals or other fertilizers used in landscaping could be pulled into the potable water system.
What is a backflow preventer and how does it prevent cross connections?
A backflow preventer, simply put, does as the name implies—it prevents the backflow of water through itself. The way it works is through a series of springs, seals, check valves and other mechanical features which activate if a pressure differential occurs. The two types of backflow preventers are dual check valve or reduced pressure zone (RPZ). A dual check valve backflow device prevents cross connection with non-health hazard applications and, when activated, simply holds the back flow in the piping systems. A reduced pressure zone (RPZ) backflow device is installed in systems to prevent the backflow of health hazardous or polluted material. When it activates, the check valves close and there is a mechanism in the body of the valve which dumps the contaminants out of the valve and, therefore, the system. These valves are located outdoors or elevated above ground, often in thermal boxes to prevent freezing. In the event of a failure, the backflow device will dump water onto the ground, which will make the property owner aware of a malfunction. If located indoors, RPZ devices are equipped with an air gap and discharge drain which catches the water coming from the RPZ relief and directs it either to a drain or outdoors to prevent property damage.
What backflow services does Hardy provide?
Hardy Services offers a full range of backflow services, from testing and rebuilding to replacing. If you receive a notice from the Water Works Board about having your property’s backflow device tested, Hardy Services will perform the test with little to no interruption to the property or facility. We will also handle the paperwork by sending the test results to the Water Works Board. If, for whatever reason, the backflow device is found to be malfunctioning, Hardy Services will present a quote to the property owner detailing what needs to be replaced or rebuilt and a time frame when the work can be performed.