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How to Avoid Health Hazard in Plumbing Cross Connections


Quiz Questions

1.Air gap is the unobstructed vertical distance through the free atmosphere between the lowest opening from any pipe or faucet supplying water to a tank, plumbing fixture, or other device and the floodlevel rim of the receptacle.
True
False
2. Backflow is the flow of water or other liquids, mixtures, or substances into the distributing pipes of a potable supply of water from any source or sources other than its intended source. Backsiphonage is one type of backflow.
True
False
3.Cross-Connection is any actual or potential connection between the public water supply and a source of contamination or pollution.
True
False
4.Potable Water is water free from impurities present in amounts sufficient to cause disease or harmful physiological effects. Its bacteriological and chemical quality shall conform to the requirements of the USEPA National Primary Drinking Water Regulations and the regulations of the public health authority having jurisdiction.
True
False
5.In Chapter 2, "Burned in the shower" , the sodium hydroxide had got into the water main line because:
When the water main broke, a truck driver was adding the water from the bottom of the tank truck instead of the top, and sodium hydroxide backsiphoned into the water main.
Extra pressure in the pipes.
6.In "Boiler water enters high school drinking water" case, the boiler water (chromium used in the heating system boilers to inhibit corrosion of metal parts) entered the potable water supply system as a result of backflow through leaking check valves on the boiler feed lines.
True
False
7.In Fig. 9. One of the common occurrences of dynamically reduced pipe pressures is found on the suction side of a pump. In many cases similar to the one illustrated in Figure 9, the line supplying the booster pump is undersized or does not have sufficient pressure to deliver water at the rate at which the pump normally operates. The rate of flow in the pipe may be increased by a further reduction in pressure at the pump intake. This often results in the creation of negative pressure at the pump intake. This often results in the creation of negative pressure.
True
False
8.There are six basic types of devices that can be used to correct cross-connections: airgaps, barometric loops, vacuum breakers—both atmospheric and pressure type, double check with intermediate atmospheric vent, double check valve assemblies, and reduced pressure principle devices. In general, all manufacturers of these devices, with the exception of the barometric loop, produce them to one or more of three basic standards, thus insuring the public that dependable devices are being utilized and marketed.
True
False
9.The major standards in the industry are: American Society of Sanitary Engineers ASSE), American Water Works Association (AWWA), and the University of California Foundation for Cross-Connection Control and Hydraulic Research.
True
False
10.Figure 15 shows a typical atmospheric breaker. Construction consists usually of a polyethylene float which is free to travel on a shaft and seal in the uppermost position against atmosphere with an elastomeric disc. Water flow lifts the float, which then causes the disc to seal. Water pressure keeps the float in the upward sealed position. Termination of the water supply will cause the disc to drop down venting the unit to atmosphere and thereby opening downstream piping to atmospheric pressure, thus preventing backsiphonage.
True
False
11.Atmospheric breakers are among the simplest and least expensive mechanical types of backflow preventers and, when installed properly, can provide excellent protection against backsiphonage. They must not be utilized to protect against backpressure conditions.
True
False