Cross-Connection Control

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Cross-Connection Control

• This is the subtitle

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What is it?

• Actual cross-connection
• Potential cross-connection
• Potable water
• Non-potable fluid
• Backflow

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Hazards of Backflow Contamination

• Biological hazards
• Chemical hazards
• Physical hazards

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Contamination of Water from Backflow

• Backflow contamination
• Link Force
• Elimination or control of cross-connection

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Conditions That Cause Bckflow

• Backpressure backflow
• Definition the reverse from the normal flow
  direction within a piping system that is the
  result of the downstream pressure being higher
  than the supply pressure.

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Conditions That Cause Backflow

• Pressurized Systems
• Pumped or pressurized
• Pipe carries fluid other than potable water

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Conditions That Cause Backflow (continued)

• Elevated Piping
• Delivery point higher than supply
• High-rise buildings
• Storage tanks

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Conditions That Cause Backflow

• Thermal Expansion
• Boilers
• Solar water heaters

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Finding Backpressure Backflow Potential

• To find potential backpressure backflow problems,
  ask yourself the question
• Where is the pressure higher than the system of
  supply pressure?
• or
• Where could the pressure be higher than the
  system or supply pressure?

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Backsiphonage Backflow

• Definition the reverse from the normal flow
  direction within a piping system that is the
  result of a partial vacuum (negative pressure)
  within the piping system.

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Causes of Backsiphonage Backflow

• Pumping systems
• Suction side
• Booster pumps
• Pump priming with potable water

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Causes of Backsiphonage Backflow

• Elevated Piping
• Drop in system of supply pressure
• Vacuum created in high points of piping
• Draining pipes for maintenance
• Breaks in lines at lower elevations

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Causes of Backsiphonage Backflow

• Venturi Effect
• High velocity reduces pressure in line
• Backsiphonage at pipe connections
• Overpumping of supply lines
• Fire flows
• Line restrictions (valves half-closed)
• Undersized pipes and fittings

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Backsiphonage Backflow (continued)

• To find potential backsiphonage backflow
  problems, ask yourself the question
• Where is the system pressure lower than the
  downstream pressure?
• or
• Where could the system pressure be lower than
  the downstream pressure?

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Types of Backflow Prevention Assemblies

• Physical Protective Assembly
• Air gap 2 x pipe diameter (min. 1 inch)
• Mechanical Protective Assembly
• Double-check valve assembly
• Reduced pressure zone assembly
• Vacuum breaker
• Pressure vacuum breaker
• Atmospheric vacuum breaker

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Double Check Valve Assembly

• 2-spring-loaded check valves
• Pressure relief valve
• 2-shutoff valves
• 4-test connections (test cocks)

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Reduced Pressure Zone Backflow Assembly (RPZ)

• 2-spring-loaded check valves
• Pressure relief valve
• 2-shutoff valves
• 4-test connections (test cocks)

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Vacuum Breaker

• Pressure vacuum breaker
• 1-spring-loaded check valve
• Air inlet valve
• 2-shutoff valves
• 2-test connections

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Vacuum Breaker

• Atmospheric vacuum breaker
• Float check valve only

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Other Devices

• Residential check valve
• Dual check with atmospheric vent
• In-line faucet and hose bibb device

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Testing and Maintenance of Assemblies

• Testing required
• after installation
• after repairs
• after being moved or reinstalled
• annually
• more often, if required
• Requires a State-certified Tester

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Safety Concerns

• Confined space
• Electrical grounding
• Hazardous materials

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Cross-Connection Control Program

• Local enforcement
• Program authority
• Prioritize existing facilities
• Regular inspections

• New installations
• Approved assemblies
• Certified testers
• Record maintenance