Presentation on theme: "1 NBL Plumbing Cross Connections and Backflow Prevention Program NBL Plumbing System Inspection December 2009."— Presentation transcript:
1 NBL Plumbing Cross Connections and Backflow Prevention Program NBL Plumbing System Inspection December 2009
2 Purpose of Cross Connection Backflow 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.
3 Magnitude of Problem in 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.
4 Reasons Why Water Contamination Events May Be 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.
5 Legal Requirements EPA Safe Drinking Water Act 1974 (latest amendment 1996) EPA Safe Drinking Water Act 1974 (latest amendment 1996) IL Health/Plumbing Code (Sections dealing with cross connections/backflow protection) IL Health/Plumbing Code (Sections dealing with cross connections/backflow protection) TITLE 77: PUBLIC HEALTH CHAPTER I: DEPARTMENT OF PUBLIC HEALTH SUBCHAPTER r: WATER AND SEWAGE PART 890 ILLINOIS PLUMBING CODE OSHA OSHA (b)(2)
6 Types 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.
7 Definitions Backflow - a reversal in the normal direction of flow within a piping system. This can occur in two ways.
8 Backflow Situations Backflow Situations Common cause of Backflow due to the siphon effect
9 Backflow Situations
10Definitions Example of Back Siphon effect Example of Back Siphon effect
11 Definitions Backpressure-process piping pressure may overcome the incoming city pressure Backpressure-process piping pressure may overcome the incoming city pressure
14 Types of Backflow Preventers Five basic devices are used to protect against cross connections: 1. Air gaps 2. Atmospheric vacuum breakers 3. Pressure vacuum breakers 4. Double check valves 5. Reduced-pressure principle backflow preventers or reduced pressure zones.
15 Historic Example 1 US EPA Cross Connection Manual 1989
16 Historic Example 2 US EPA Cross Connection Manual 1989
17 Historic Example 3 US EPA Cross Connection Manual 1989
18 Historic Example 4 US EPA Cross Connection Manual 1989
19 Common Cross 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
20 Highlights NBL Backflow Cross Connection Inspection December 2009
21 4 Separate Water Systems at NBL 1. (potable – i.e. water fountains, lavatory sinks, break room kitchen sink, etc.) 1. Domestic (potable – i.e. water fountains, lavatory sinks, break room kitchen sink, etc.) 2. Lab (lab faucets, etc.) 3. Distilled (de-ionized water) 4. Canal (i.e. outside cooling towers, chillers, etc.)
22 Backflow Preventer Pu mens lockeroom janitors closet detergent sprayer with newly installed backflow preventer (installed 12/14/09). U wing janitors closet with backflow preventer.
23 Air 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.
24 Submerged Inlet Pipette washer submerged inlet. NBL lab sink faucets do not have intrinsic backflow preventers.
25 Prevention 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.
26 Double Check Valve Backflow Preventer 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.
27 No Backflow Preventer Industrial Motor Connected to Potable Water Line Auxillary pump cooling jacket in Pu basement B connected to potable water line without backflow preventer.
28 Washing Machine Connections Needing 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).
29 Aspirator Without Backflow Prevention 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.
31 Cross Connection and no backflow preventer to potable water line Pu Basement Acid Scrubber. Cross connection lab and distilled water. Potable water connection to scrubber. Potable water line has no fixed backflow preventer.
32 Perchloric Acid Hood Perchloric acid hood water spray in C138 needs back flow preventer.
33 Drain Lines Not Capped Uranium wing drain lines not capped. Stain on floor C218 possibly spill from uncapped drain.
34 Dried Out Lab Sink Traps Old sink possibly with dried out trap Plug for sink drain.
35 Dried 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.
36 Non Potable Water Supply Uranium 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.