ABC Cross-Connection Control and Monitoring Flashcards

What is a cross-connection in a potable water system?

Answer: A link between a potable supply and a potential source of contamination

A cross-connection is any physical connection between a potable water supply and a non-potable source that could allow contamination to enter the drinking water.

What phenomenon causes backflow from a high-pressure non-potable source into the potable water system?

Answer: Back-pressure backflow

Back-pressure backflow occurs when downstream pressure exceeds supply pressure, forcing non-potable water backward into the potable system.

Which backflow preventer provides the highest level of protection and is required for high-hazard cross-connections?

Answer: Reduced Pressure Zone (RPZ) assembly

The Reduced Pressure Zone (RPZ) assembly provides the highest level of backflow protection and is required for high-hazard applications such as chemical injection systems.

What type of backflow occurs when a drop in supply pressure creates a vacuum that siphons contaminants into the potable water system?

Answer: Backsiphonage

Backsiphonage is caused by negative pressure (vacuum) in the supply line that draws contaminants backward into the potable system.

Under the USC Model Cross-Connection Control Program, which device is approved for protection against backsiphonage only and must not be installed under continuous pressure?

Answer: Atmospheric vacuum breaker

The atmospheric vacuum breaker (AVB) is approved only for backsiphonage conditions and must not be subjected to continuous downstream pressure.

What is the minimum air gap required between a potable water supply outlet and the flood rim of a receiving vessel, per ASME/ANSI standards?

Answer: Two times the diameter of the supply pipe or 1 inch, whichever is greater

ASME A112.1.2 specifies that the air gap must be at least twice the effective opening diameter or 1 inch, whichever is greater.