11

NBL Plumbing Cross NBL Plumbing Cross Connections and Connections and

Backflow Prevention Backflow Prevention Program Program

NBL Plumbing System NBL Plumbing System Inspection December 2009Inspection December 2009

22

Purpose of Cross Connection Purpose of Cross Connection Backflow ProgramBackflow Program

The purpose of a cross connection and backflow control program is to ensure that potable water is safe to drink by verifying that no potential or actual cross connections with non-potable water exist.

33

Magnitude of Problem in Magnitude of Problem in U.S.*U.S.*

From 1981 to 1998, CDC documented 57 waterborne disease outbreaks related to cross connections, resulting in 9,734 illnesses. 20 outbreaks (6,333 cases of illness) caused by

microbiological contamination. 15 outbreaks (679 cases of illness) caused by

chemical contamination. 22 outbreaks (2,722 cases of illness) where the

contaminant was not reported.

Note: The CDC believes many cases of waterborne illness are not recognized or reported.

*US EPA Office of Ground and Drinking Water, Potential Contamination Due to Cross Connections and Backflow and Associated Risks, 2001.

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Reasons Why Water Reasons Why Water Contamination Events May Be Contamination Events May Be

Under-reported*Under-reported* Outbreaks of illness may not be linked to an incident of

backflow contamination. Documented effects of contamination are usually acute and

result from short-term exposures; whether mild or severe, the effect appears soon after exposure. Effects that are long-lasting or only appear after some time (chronic effects) are difficult to ascribe to a single event or associate with a waterborne source.

Cross-connections combined with uncorrected backflow situations that cause continuous or intermittent exposure over a long time and result in chronic illness would be less likely to be linked to backflow contamination.

Contamination may not affect enough people to attract the attention of public health officials.

Information that could tie an incident to an outbreak of illness or disease, such as where and when a contaminant entered the system, is often missing.

*US EPA Office of Ground and Drinking Water, Potential Contamination Due to Cross Connections and Backflow and Associated Risks, 2001.

55

Legal RequirementsLegal Requirements

EPA Safe Drinking Water Act 1974 EPA Safe Drinking Water Act 1974 (latest amendment 1996)(latest amendment 1996)

IL Health/Plumbing Code (Sections IL Health/Plumbing Code (Sections dealing with cross dealing with cross connections/backflow protection) connections/backflow protection)

TITLE 77: PUBLIC HEALTH TITLE 77: PUBLIC HEALTH CHAPTER I: DEPARTMENT OF PUBLIC CHAPTER I: DEPARTMENT OF PUBLIC

HEALTHHEALTHSUBCHAPTER r: WATER AND SEWAGESUBCHAPTER r: WATER AND SEWAGEPART 890 ILLINOIS PLUMBING CODEPART 890 ILLINOIS PLUMBING CODE

OSHA OSHA 1926.51(b)(2)

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Types of Cross ConnectionsTypes of Cross Connections Backflow is the undesirable reversal of flow of water or

other substances or mixtures into the drinking water distribution system.

Back siphonage is caused by negative pressure (vacuum) in the supply line. This effect is similar to sipping a coke by inhaling through a straw, which induces a flow in the opposite direction.

Back pressure is caused by higher pressure in the system than is in the supply line. This can be caused by turning on a pump in the system that has a higher pumping pressure than that of the supply line. If the pump line is contaminated with a hazardous chemical, the higher pressure in the system could force the hazardous chemical back into the supply line or water main.

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DefinitionsDefinitions Backflow - a reversal in the normal Backflow - a reversal in the normal direction of flow within a piping system. direction of flow within a piping system. This can occur in two ways. This can occur in two ways.

88

Backflow SituationsBackflow Situations Common cause of Backflow due to Common cause of Backflow due to

the siphon effectthe siphon effect

99

Backflow SituationsBackflow Situations

1010

DefinitionsDefinitions

Example of Back Siphon effectExample of Back Siphon effect

1111

Definitions Backpressure-process piping pressure Backpressure-process piping pressure may overcome the incoming city pressuremay overcome the incoming city pressure

1212

1313

1414

Types of Backflow Types of Backflow PreventersPreventers

Five basic devices are used to protect against cross connections: 1. Air gaps2. Atmospheric vacuum breakers 3. Pressure vacuum breakers4. Double check valves5. Reduced-pressure principle backflow

preventers or reduced pressure zones.

1515

Historic Example 1Historic Example 1

US EPA Cross Connection Manual 1989

1616

Historic Example 2 Historic Example 2

US EPA Cross Connection Manual 1989

1717

Historic Example 3Historic Example 3

US EPA Cross Connection Manual 1989

1818

Historic Example 4Historic Example 4

US EPA Cross Connection Manual 1989

1919

Common Cross Common Cross Connections*Connections*

Where are the most common cross-connections found?

Whenever a plumbing fixture is connected to the drinking water supply, a potential cross-connection exists. Fortunately, many of the plumbing fixtures have built-in backflow protection. Here are some examples of cross-connections that can lead to backflow are:

• Wash basins and service sinks• Laboratory equipment• Irrigation or lawn sprinkler systems• Swimming pools and spas• Solar heat systems• Fire sprinkler systems• Auxiliary water supplies (wells, storage tanks and second feeds)• Photo developing equipment• Chemical feed equipment• Attachment to hoses to apply weed killer or fertilizer or to flush antifreeze• Food and beverage processing equipment• Ornamental fountains• Boilers• Hose bibs

*City of San Diego, Water Department

2020

HighlightsHighlights

NBL Backflow Cross Connection NBL Backflow Cross Connection InspectionInspection

December 2009December 2009

2121

4 Separate Water Systems at 4 Separate Water Systems at NBLNBL

1. Domestic (potable – i.e. water (potable – i.e. water fountains, lavatory sinks, break fountains, lavatory sinks, break room kitchen sink, etc.)room kitchen sink, etc.)

2.2. LabLab (lab faucets, etc.) (lab faucets, etc.)

3.3. DistilledDistilled (de-ionized water) (de-ionized water)

4.4. CanalCanal (i.e. outside cooling towers, (i.e. outside cooling towers, chillers, etc.)chillers, etc.)

2222

Backflow Preventer Backflow Preventer

Pu men’s lockeroom Pu men’s lockeroom janitors closet detergent janitors closet detergent sprayer with newly sprayer with newly installed backflow installed backflow preventer (installed preventer (installed 12/14/09). 12/14/09).

U wing janitors closet with backflow preventer.

2323

Air GapAir Gap

Emergency eyewash without air gap for drain.

Emergency eyewash with air gap for drain

Note: Many Emergency Showers and eyewashes incorrectly connected to lab water rather than potable (domestic) water system.

2424

Submerged InletSubmerged Inlet

Pipette washer submerged inlet. NBL lab sink faucets do not have intrinsic backflow preventers.

2525

Prevention Submerged InletPrevention Submerged Inlet

Hoses cut above level of sink prevents a submerged inlet.

Hose below level of sink creating potential submerged inlet. NBL lab sink faucets do not have intrinsic backflow preventers.

2626

Double Check Valve Backflow Double Check Valve Backflow PreventerPreventer

Pu Basement B water main dividing into potable water and standpipe (sprinkler) line without double check valve backflow preventer.

Uranium Wing C057 water main dividing into potable water and standpipe (sprinkler) line with double check valve backflow preventer.

2727

No Backflow Preventer Industrial No Backflow Preventer Industrial Motor Connected to Potable Water Motor Connected to Potable Water

LineLine

Auxillary pump cooling jacket in Pu basement B connected to potable water line without backflow preventer.

2828

Washing Machine Connections Washing Machine Connections Needing Backflow PreventerNeeding Backflow Preventer

Pu Rad Washing Machine Water connections needing backflow preventer. Need in Uranium Wing D114.

Washing machine backflow preventer. Special type recommended for radiological facilities (reduced pressure zone double check valve).

2929

Aspirator Without Backflow Aspirator Without Backflow PreventionPrevention

Aspirator without backflow preventer D118 U wing. NBL lab sink faucets do not have intrinsic backflow preventers. Only use aspirator on sink faucet that has back flow preventer – ask Building Manager.

3030

Hose Bib Vaccum Breaker Hose Bib Vaccum Breaker Backflow PreventerBackflow Preventer

Hose bib with newly installed (12/14/09) backflow preventer (vacuum breaker) Room C057

3131

Cross Connection and no Cross Connection and no backflow preventer to potable backflow preventer to potable

water linewater line

Pu Basement Acid Scrubber. Cross connection lab and distilled water. Potable water connection to scrubber. Potable water line has no fixed backflow preventer.

3232

Perchloric Acid HoodPerchloric Acid Hood

Perchloric acid hood water spray in C138 needs back flow preventer.

3333

Drain Lines Not CappedDrain Lines Not Capped

Uranium wing drain lines not capped. Stain on floor C218 possibly spill from uncapped drain.

3434

Dried Out Lab Sink TrapsDried Out Lab Sink Traps

Old sink possibly with dried out trap Plug for sink drain.

3535

Dried Out Lab Cup SinksDried Out Lab Cup Sinks

Lab cup sink with dried out trap. If trap is dried it will probably be positively pressured relative to room. Periodically fill trap with water or cover with parafilm or cellophane.

3636

Non Potable Water Supply Non Potable Water Supply Uranium Distillation ApparatusUranium Distillation Apparatus

Uranium wing distillation apparatus for de ionized water. The device is fed by a steam line which is non-potable. Do not drink water from distillation apparatus.