A Cross-Connection is a. water system and a nonpotable CROSS-CONNECTION CONTROL BACKFLOW PREVENTION CROSS-CONNECTION CROSS-CONNECTION

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1 CROSS-CONNECTION CONTROL and BACKFLOW PREVENTION Les O Brien, UF/TREEO Center CROSS-CONNECTION is any connection between a potable water system and any source of contamination through which contaminated water could enter the potable water system. CROSS-CONNECTION A Cross-Connection is a LINK between a potable water system and a nonpotable system. POTENTIAL CROSS-CONNECTION Situations in which some of the conditions for a cross-connection exist, but require something else to be done to complete the connection. Permanent and Temporary

2 BACKFLOW is the flow of any water, foreign liquids, id gases, or other substances back into a potable water system. BACKFLOW The Reversal of the normal ldirection i of fflow. BACKPRESSURE is a condition in which the foreign substance is forced into a water system because it is under higher pressure than the system pressure. BACKPRESSURE The customer s pressure is greater than the supply pressure. 60 psi 70 psi

3 BACKSIPHONAGE is a condition under which the water system pressure is less than atmospheric (vacuum), and the foreign substance is essentially sucked into the potable water system. BACKSIPHONAGE Backflow caused by negative or reduced d pressure in the supply piping. BACKSIPHONAGE Backflow caused by negative or reduced d pressure in the supply piping. CONTAINMENT SERVICE PROTECTION Chapter ISOLATION METER TO CUSTOMER INTERNAL PROTECTION Chapter Chapter 3

4 TOIC NON-TOIC CONTAMINANT HIGH HEALTH POLLUTANT LOW NON-HEALTH Chapter Chapter PURVEYOR The supplier / owner of the public water supply. CASE HISTORIES 933 Chicago World s Fair 969 Holy Cross College, Worcester, MA 976 Chattanooga, TN 988 Belle Glade, FL Chapter DEVICE ASSEMBLY ATMOSPHERIC VACUUM BREAKER (A.V.B.) 4

5 AIR INLET CHECK NORMAL FLOW ATMOSPHERIC VACUUM BREAKER NORMAL FLOW AIR ENTERS AIR ENTERS BACKSIPHONAGE BACKPRESSURE CAUSES AIR INLET TO STICK Atmospheric Pressure Minimum of 6 above highest outlet 5

6 ATMOSPHERIC VACUUM BREAKER Summary of Applications for Backflow Protection No Valve Downstream AVB PVB DCVA RP AG No Backpressure Single Fixture Application i Non-Continuous Use Turn off every - 4 hours Should be Inspected Annually BACKSIPHONAGE BACKPRESSURE HIGH LOW HIGH LOW PRESSURE VACUUM BREAKER (P.V.B.) CANOPY CANOPY TC # TC # AIR INLET VALVE CRITICAL LEVEL TC # INLET VALVE OUTLET VALVE PRESSURE VACUUM BREAKER CRITICAL LEVEL TC # INLET VALVE CHECK VALVE OUTLET VALVE PRESSURE VACUUM BREAKER 6

7 AIR ENTERS TC # TC # OUTLET VALVE OUTLET VALVE TC # TC # INLET VALVE BACKSIPHONAGE TC # TC # INLET VALVE Air Inlet stuck closed backpressure PRESSURE* VACUUM BREAKER Protects against backsiphonage ONLY! CL must be above downstream use Must be tested at least once a year * CONTINUOUS PRESSURE Summary of Applications for Backflow Protection BACKSIPHONAGE BACKPRESSURE AVB PVB DCVA RP AG HIGH LOW HIGH LOW DOUBLE CHECK VALVE ASSEMBLY (D.C.V.A.) 7

8 3 4 CV # CV # Outlet valve closed Outlet valve opened 8

9 DCVA Installation DOUBLE CHECK VALVE ASSEMBLY There is no height requirement Assembly should be easily and safely accessible. Installation should conform to OSHA Regulations DCVA installed on low hazard ONLY! Protects against Low Hazard ONLY! Both springs same, > or = to.0 psi Maximum pressure drop - 0 psi. Must be tested at least once a year Used on some Fire Sprinkler Systems Summary of Applications for Backflow Protection AVB PVB DCVA RP AG HIGH BACKSIPHONAGE LOW HIGH BACKPRESSURE LOW DCDA 9

10 REDUCED PRESSURE PRINCIPLE BACKFLOW PREVENTION ASSEMBLY =RP psi 95 psi 0

11 94 psi 00 psi 95 psi 94 psi 00 psi DUMPS THE ZONE 3 4 SPITS 00 psi 95 psi DRIPS STEADILY 00 psi + 95 CV Leaks 00 psi 95 psi 05 psi 00 psi 95 psi 05 psi 00 psi + 95 Backpressure 00 psi Backpressure and CV fails

12 REDUCED PRESSURE PRINCIPLE ASSEMBLY Summary of Applications for Backflow Protection Protects against High Hazard, Backpressure & Backsiphonage RV > or = to.0 psi CV # 3.0 psi > RV opening CV # > or = to.0 psi RV Vent to 36 inches above grade Must be tested at least once a year BACKSIPHONAGE BACKSIPHONAGE BACKPRESSURE BACKPRESSURE AVB PVB DCVA RP RP AG AG HEALTH HIGH NON-HEALTH LOW HEALTH HIGH NON-HEALTH LOW AIR GAP times the I.D. of the supply pipe or Minimum of inch. Flood Rim AIR GAP Summary of Applications for Backflow Protection AVB PVB DCVA RP AG WHAT SINGLE ITEM AT HOME CAUSES OVER HALF OF THE CROSS-CONNECTION ACCIDENTS IN THIS COUNTRY? BACKSIPHONAGE BACKPRESSURE HIGH LOW HIGH LOW The Common Garden Hose Would you let your children drink from a hose that you just used to clean out your sewer line?

13 Backflow Incidents The problems: WHY CROSS-CONNECTIONS EIST: unaware of problem convenience inadequate devices Inadequate Education and Training: Engineers & Architects Contactors Inspectors Health officials Customers 3

14 Plumbing Codes (IPC) Code only refers to new construction Annual testing required only on approved, testable assemblies Backflow devices cannot be tested There are no testing and maintenance requirements for backflow devices What are the odds that a backflow incident will happen in your community? We need: backflow and a cross-connection Murphy's laws If anything can go wrong, it will. Sometimes Murphy helps out. If there is a possibility of several things going wrong, the one that will cause the most damage will be the one to go wrong. If anything just cannot go wrong, it will anyway. 4

15 Left to themselves, things tend to go from bad to worse. Quantization Revision of Murphy's Laws Everything goes wrong all at once. How many water main breaks happen each day? Gainesville has 45,000 metered customers and 000 miles of water mains. Gainesville averages water main breaks each day. That is neighborhoods each day that experience a drop in pressure. BACKFLOW Now, all we need is that cross-connection. What single item at home causes the most backflow incidents? The common Garden Hose 5

16 Commercial products: There are dozens of products available to the public These products can create a cross- connection These products do not have warning labels There is no control over the manufacture and sale of these dangerous products Commercial products: There are dozens of products available to the public These products can create a cross- connection These products do not have warning labels There is no control over the manufacture and sale of these dangerous products Commercial products: There are dozens of products available to the public These products can create a cross- connection These products do not have warning labels There is no control over the manufacture and sale of these dangerous products Commercial products: There are dozens of products available to the public These products can create a cross- connection These products do not have warning labels There is no control over the manufacture and sale of these dangerous products. Let s look at some of the products the uneducated public purchase and then connect to their garden hose. 6

17 NO AIR GAP 7

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19 Refill Your Dog s Water Bowl Automatically! 9

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21 AIR GAP NO AIR GAP Maybe a little public education would help. More Information:

22 The topic for the next Buster may focus on reuse water for homeowners.

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24 GIL 0 4 Number of UF/TREEO Backflow Testers in each County GL BRAD BRAD 0 GIL Number of UF/TREEO Backflow Testers in each County Number of UF/TREEO Backflow Testers in each County

25 Also: Jackson Duval 3 Number of ASSE Backflow Testers in each County FS/AWWA Endorsed Backflow Tester Training Organizations. UF/TREEO Center. Florida Water and Pollution Control Association (FW-PCOA) 3. the Florida Plumbing Apprenticeship School in West Palm Beach 4. ICCC in Hollywood 5. MTI EPA White paper: Potential Contamination Due to Cross-Connections and Backflow and the Associated Health Risks Prevalence of Cross- Connections in Household Plumbing Systems 5