Qualified Cross Connection Control Management and inspection by Source to Tap Water Management Inc.
Cross Connection Control Help
A cross connection shall be defined as an existing connection or a potential connection between any part of a potable water system and any other environment containing other substances in a manner which, under any circumstances, would allow such substances to enter the potable water system. Other substances may be gases, liquids or solids such as chemicals, waste products, steam, water from other sources (potable or non potable), or any matter, which may change the colour or add odour to the water.
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Definitions from the Pacific Northwest Section of the American Waterworks Association (PNWS-AWWA) Cross Connection Control Manual;
Hazards shall be defined in the following three categories:
(a) Minor hazard - any cross connection or potential cross connection that constitutes only a nuisance, with no possibility of any health hazard;
(b) Moderate hazard - any minor hazard as defined in item (a) that has a low probability of becoming a severe hazard;
Note: With this type of hazard, secondary protection by means of zone or premises isolation with a reduced pressure principle device or an air gap may be required.
(c) High or Severe hazard - any cross connection or potential cross connection involving any substance that could be a danger to health.
Note: This clause deals with the assessment of the potential hazard and the probability that backflow could occur. There is no simple method to qualify the problem by assessing the relevant factors, nor can the devices be categorized numerically according to the degree of protection they provide.
Devices and assemblies installed must be of an approved type as defined by CAN/CSA-B64-94.
Maintenance and field-testing shall be carried out as per CSA B64.10.1-01
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The most common cause of contamination due to backflow/backsiphonage is the simple misapplication of the garden hose.
This is also the least expensive cross connection to eliminate.
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Pressure vacuum breaker (PVB), is an assembly containing an independently acting check valve force loaded or biased in the normally open position and located on the discharge side of the check valve. The assembly is equipped with properly located resilient seated test cocks and tightly closing resilient seated shut off valves located at each end of the assembly.
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Backpressure is the reversal of normal water flow due to an elevated pressure in the water lines of a system causing water to flow back into the supply line. This can occur due to a booster pump or other pressure device, such as a boiler, acting on the supply water distribution system.
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A Double Check Valve Assembly protects against reverse flow due to back pressure and back siphonage.
This device can be applied in Moderate Hazard locations.
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