Cross-Connection Control Manual Office of Water (4606M) EPA 816-R-03-002 www.epa.gov/safewater February 2003 Printed on Recycled Paper Cross-Connection Control Manual

United States Environmental Protection Agency Office of Water Office of Ground Water and Drinking Water

First Printing 1973 Reprinted 1974, 1975 Revised 1989 Reprinted 1995 Technical Corrections 2003 Preface

lumbing cross-connections, indirectly in water supply cross-connection control from Pwhich are defined as actual distribution systems. It is both the basic hydraulic or potential connections intended to be used for educa- concepts through the inclusion between a potable and non- tional, administrative, and of a sample program that can potable water supply, constitute technical reference in conduct- be a guide for a program at the a serious public health hazard. ing cross-connection control municipal level. New backflow There are numerous, well- programs. This manual is a devices have been included in documented cases where cross- revision of an earlier book this revision that are now being connections have been respon- entitled Water Supply and produced by manufacturers sible for contamination of Plumbing Cross-Connections (PHS reflecting the needs of the drinking water, and have Publication Number 957), market. Updated actual cross- resulted in the spread of disease. which was produced under the connection case histories have The problem is a dynamic one, direction of Floyd B. Taylor by been added containing graphic because piping systems are Marvin T. Skodje, who wrote schematic illustrations showing continually being installed, the text and designed the how the incidents occurred and altered, or extended. illustrations. how cross-connection control Control of cross-connec- Many of the original practices could be applied to tions is possible, but only illustrations and text have been eliminate future re-occurrence. through thorough knowledge retained in this edition. Previ- A more detailed explanation of and vigilance. Education is ous revisions were done by cross-connection control essential, for even those who are Peter C. Karalekas, Jr. with “containment” practice has experienced in piping installa- guidance from Roger D. Lee been included together with the tions fail to recognize cross- incorporating suggestions made use for “internal backflow connection possibilities and by the staff of the EPA Water protective devices” and “fixture dangers. All municipalities with Supply Division, other govern- outlet protection”. public water supply systems mental agencies, and interested This 1989 edition was should have cross-connection individuals. prepared by Howard D. control programs. Those This 3rd edition was Hendrickson, PE, vice president responsible for institutional or produced as a result of an of Water Service Consultants, private water supplies should updated need for cross- with assistance from Peter C. also be familiar with the connection control reference Karalekas, Jr. of Region 1, EPA, dangers of cross-connections material reflecting an increase Boston. and should exercise careful in cross-connection control This latest (2003) edition surveillance of their systems. activity throughout the United has technical corrections This Cross-Connection Control States. It has been revised and provided by Howard D. Manual has been designed as a re-issued reflecting a demand Hendrickson, P.E., showing tool for health officials, water- for its use, together with updates on pages iv, 18, 23, 30, works personnel, plumbers, and requests for a document that 31, and 32. any others involved directly or covers the broad spectrum of

ii • CROSS-CONNECTION CONTROL MANUAL Contents

American Water Works Association Policy on Cross-Connections ...... iv 11 Valved connection between potable water and sanitary sewer ...... 15 12 Air gap ...... 16 Chapter 13 Air gap in a piping system ...... 16 1. Purpose & Scope ...... 1 14 Barometric loop ...... 17 2. Public Health Significance of Cross-Connections ...... 2 15 Atmospheric vacuum breaker ...... 17 3. Theory of Backflow and Backsiphonage ...... 12 16 Atmospheric vacuum breaker typical installation ...... 17 4. Methods and Devices for the Prevention of Backflow and 17 Atmospheric vacuum breaker in plumbing supply system ...... 17 Backsiphonage ...... 16 18 Hose bibb vacuum breaker ...... 18 5. Testing Procedures for Backflow Preventers ...... 25 19 Typical installation of hose bibb vacuum breaker ...... 18 6. Administration of a Cross-Connection Control Program ...... 30 20 Pressure vacuum breaker ...... 18 7. Cross-Connection Control Ordinance Provisions ...... 33 21 Typical agricultural and industrial application of pressure vacuum breaker ...... 19 Appendixes 22 Double check valve with atmospheric vent ...... 19 A. Partial list of plumbing hazards ...... 38 23 Residential use of double check with atmospheric vent ...... 19 B. Illustrations of backsiphonage ...... 38 24 Double check valve ...... 19 C. Illustrations of backflow ...... 40 25 Double check valve detector check ...... 20 D. Illustrations of air gaps ...... 41 26 Residential dual check ...... 20 E. Illustrations of vacuum breakers ...... 41 27 Residential installation ...... 20 F. Glossary ...... 42 28 Copper horn ...... 20 G. Bibliography ...... 43 29a Reduced pressure zone backflow preventer ...... 21 H. Sample cross-connection survey form ...... 44 29b Reduced pressure zone backflow preventer ...... 21 I. Sample cross-connection test form ...... 45 30 Reduced pressure zone backflow preventer principle of operation . . . 22 31 Plating plant installation ...... 22 Illustrations 32 Car wash installation ...... 22 Human blood in the water system ...... 2 33 Typical by-pass configuration, reduced pressure principle devices . . . 23 Burned in the shower ...... 3 34 Typical installation, reduced pressure principle device, Heating system anti-freeze into potable water ...... 3 horizontal illustration ...... 23 Salty drinks ...... 4 35 Typical installation, reduced pressure principle device, Paraquat in the water system ...... 4 vertical installation ...... 23 Propane gas in the water mains ...... 5 36 Typical installation, double check valve, horizontal and vertical Chlordane and heptachlor at the Housing Authority ...... 5 installation ...... 24 Boiler water enters high school drinking water ...... 6 37 Typical installation, residential dual check with straight Pesticide in drinking water ...... 6 set and copper horn ...... 24 Car wash water in the water main ...... 7 38 Pressure vacuum breaker ...... 26 Shipyard backflow contamination ...... 7 39 Reduced pressure principle backflow preventer, Step 1 ...... 27 Chlordane in the water main ...... 8 40 Reduced pressure principle backflow preventer, Step 2 ...... 27 Hexavalent chromium in drinking water ...... 8 41 Double check valve assemblies, Method 1 ...... 28 Employee health problems due to cross-connection ...... 9 42 Double check valve assemblies, Method 2 ...... 29 Dialysis machine contamination ...... 10 43 Cross-connection protection, commercial, industrial and residential . 30 Creosote in the water mains ...... 11 44 Backsiphonage, Case 1 ...... 38 Kool aid laced with chlordane ...... 11 45 Backsiphonage, Case 2 ...... 38 46 Backsiphonage, Case 3 ...... 39 Figure 47 Backsiphonage, Case 4 ...... 39 1 Pressure exerted by one foot of water at sea level ...... 12 48 Backsiphonage, Case 5 ...... 39 2 Pressure exerted by two feet of water at sea level ...... 13 49 Backsiphonage, Case 6 ...... 39 3 Pressure on the free surface of a liquid at sea level ...... 13 50 Backflow Case 1 ...... 40 4 Effect of evacuating air from a column ...... 13 51 Backflow Case 2 ...... 40 5 Pressure relationships in a continuous fluid system at 52 Backflow Case 3 ...... 40 the same elevation ...... 13 53 Backflow Case 4 ...... 40 6 Pressure relationships in a continuous fluid system at 54 Air gap to sewer subject to backpressure—force main ...... 41 different elevations ...... 14 55 Air gap to sewer subject to backpressure—gravity drain ...... 41 7 Backsiphonage in a plumbing system ...... 14 56 Fire system makeup tank for a dual water system ...... 41 8 Negative pressure created by constricted flow ...... 14 57 Vacuum breakers ...... 41 9 Dynamically reduced pipe pressure(s) ...... 14 58 Vacuum breaker arrangement for an outside hose hydrant ...... 41 10 Valved connection between potable water and nonpotable fluid . . . . 15

TABLE OF CONTENTS • iii An AWWA Statement of Policy on Public Water Supply Matters.

Cross Connections The water purveyor shall To reduce the risk private assure that effective backflow plumbing systems pose to the dopted by the Board of prevention measures commen- public water distribution A Directors Jan. 26, 1970, surate with the degree of system, the water purveyor’s revised June 24, 1979, reaf- hazard, are implemented to backflow prevention program firmed June 10, 1984 and ensure continual protection of should include public education revised Jan. 28, 1990 and Jan. the water in the public water regarding the hazards backflow 21, 2001. distribution system. Customers, presents to the safety of The American Water together with other authorities drinking water and should Works Association (AWWA) are responsible for preventing include coordination with the recognizes water purveyors contamination of the private cross connection efforts of local have the responsibility to plumbing system under their authorities, particularly health supply potable water to their control and the associated and plumbing officials. In areas customers. In the exercise of protection of the public water lacking a health or plumbing this responsibility, water system. enforcement agency, the water purveyors or other respon- If appropriate back-flow purveyor should additionally sible authorities must prevention measures have not promote the health and safety implement, administer, and been taken, the water purveyor of private plumbing systems to maintain ongoing backflow shall take or cause to be taken protect its customers from the prevention and cross- necessary measures to ensure hazards of backflow. connection control programs that the public water distribu- to protect public water tion system is protected from systems from the hazards any actual or potential originating on the premises backflow hazard. Such action of their customers and from would include the testing, temporary connections that installation, and continual may impair or alter the water assurance of proper operation in the public water systems. and installation of backflow- The return of any water to prevention assemblies, devices, the public water system after and methods commensurate the water has been used for with the degree of hazard at the any purpose on the service connection or at the customer’s premises or point of cross connection or within the customer’s piping both. If these actions are not system is unacceptable and taken, water service shall opposed by AWWA. ultimately be eliminated.

iv • CROSS-CONNECTION CONTROL MANUAL Chapter One

ublic health officials have It might be assumed that standard backflow prevention Purpose Plong been concerned steps for detecting and elimi- devices and methods that may about cross-connections and nating cross-connections would be substituted for the conve- backflow connections in be elementary and obvious. nient but dangerous direct and Scope plumbing systems and in public Actually, cross-connections may connection. And third, it should drinking water supply distribu- appear in many subtle forms be made clear to all that the tion systems. Such cross- and in unsuspected places. hazards resulting from direct connections, which make Reversal of pressure in the connections greatly outweigh possible the contamination of water may be freakish and the convenience gained. This potable water, are ever-present unpredictable. The probability manual does not describe all the dangers. One example of what of contamination of drinking cross-connections possible in can happen is an epidemic that water through a cross- piping systems. It does attempt occurred in Chicago in 1933. connection occurring within a to reduce the subject to a Old, defective, and improperly single plumbing system may statement of the principles designed plumbing and fixtures seem remote; but, considering involved and to make it clear to permitted the contamination of the multitude of similar the reader that such installa- drinking water. As a result. systems, the probability is tions are potentially dangerous. 1,409 persons contracted great. The primary purpose is to amebic dysentery; there were define, describe, and illustrate 98 deaths. This epidemic, and typical cross-connections and to others resulting from contami- Why do such suggest simple methods and nation introduced into a water cross-connections devices by which they may be supply through improper exist? eliminated without interfering plumbing, made clear the with the functions of plumbing responsibility of public health First, plumbing is frequently or water supply distribution officials and water purveyors for installed by persons who are systems. exercising control over public unaware of the inherent water distribution systems and dangers of cross-connections. all plumbing systems connected Second, such connections are to them. This responsibility made as a simple matter of includes advising and instruct- convenience without regard to ing plumbing installers in the the dangerous situation that recognition and elimination of might be created. And, third, cross-connections. they are made with reliance on Cross-connections are the inadequate protection such as a links through which it is single valve or other mechanical possible for contaminating device. materials to enter a potable To combat the dangers of water supply. The contaminant cross-connections and backflow enters the potable water system connections, education in their when the pressure of the recognition and prevention is polluted source exceeds the needed. First, plumbing pressure of the potable source. installers must know that The action may be called hydraulic and pollutional backsiphonage or backflow. factors may combine to produce Essentially it is reversal of the a sanitary hazard if a cross- hydraulic gradient that can be connection is present. Second, produced by a variety of they must realize that there are circumstances. available reliable and simple

CHAPTER ONE • 1 Chapter Two Human Blood in the Water System

ealth Department officials Investigation revealed that Public Health Hcut off the water supply to the funeral home had been a funeral home located in a using a hydraulic aspirator to large southern city, after it was drain fluids from the bodies of Significance of determined that human blood human “remains” as part of the had contaminated the fresh embalming process. The Cross-Connections water supply. City water and aspirator directly connected to plumbing officials said that they the water supply system at a did not think that the blood faucet outlet located on a sink ublic health officials have contamination had spread in the “preparation” (embalm- Plong been aware of the beyond the building, however, ing) room. Water flow through impact that cross-connections inspectors were sent into the the aspirator created suction play as a threat to the public neighborhood to check for that was utilized to draw body health. Because plumbing possible contamination. The fluids through a hose and defects are so frequent and chief plumbing inspector had needle attached to the suction the opportunity for contami- received a telephone call side of the aspirator. nants to invade the public advising that blood was coming The contamination of the drinking water through cross- from drinking fountains within funeral home potable water connections are so general, the building. Plumbing and supply was caused by a combi- enteric illnesses caused by county health department nation of low water pressure in drinking water may occur at inspectors went to the scene conjunction with the simulta- most any location and at any and found evidence that the neous use of the aspirator. time. blood had been circulating in Instead of the body fluids The following documented the water system within the flowing into the sanitary drain, cases of cross-connection building. They immediately they were drawn in the opposite problems illustrate and ordered the building cut off direction—into the potable emphasize how actual cross- from the water system at the water supply of the funeral connections have compromised meter. home! the water quality and the public health. Normal operation Positive supply pressure Potable water Open

Closed

Negative supply pressure Open “Hydro” aspirator Closed

Reverse flow through aspirator due to Body fluids back siphonage

2 • CROSS-CONNECTION CONTROL MANUAL Burned in the Heating System Shower Anti-Freeze into Potable Water resident of a small town in One neighbor’s head was angor Maine Water AAlabama, jumped in the covered with blisters after she B Department employees shower at 5 a.m. one morning washed her hair and others discovered poisonous antifreeze in October, 1986, and when he complained of burned throats in a homeowner’s heating got out his body was covered or mouths after drinking the system and water supply in with tiny blisters. “The more I water. November, 1981. The incident rubbed it, the worse it got,” the The incident began after an occurred when they shut off 60 year old resident said. “It 8-inch water main, that fed the ‘the service line to the home to looked like someone took a town, broke and was repaired. make repairs. With the flow of blow torch and singed me.” While repairing the water water to the house cut off, He and several other main, one workman suffered pressure in the lines in the residents received medical leg burns from a chemical in house dropped and the anti- treatment at the emergency the water and required medical freeze, placed in the heating room of the local hospital after treatment. Measurements of the system to prevent freeze-up of the water system was contami- ph of the water were as high as an unused hot water heating nated with sodium hydroxide, a 13 in some sections of the pipe. system, drained out of the strong caustic solution. Investigation into the cause heating system into house Other residents claimed of the problem led to a possible water lines, and flowed out to that, “It (the water) bubbled up source of the contamination the street. If it had not been and looked like Alka Seltzer. I from a nearby chemical noticed, it would have entered stuck my hand under the faucet company that distributes the homeowner’s drinking and some blisters came up.” chemicals such as sodium water when the water pressure hydroxide. The sodium hydrox- was restored. ide is brought to the plant in

Chemical bulk storage and holding tanks liquid form in bulk tanker trucks and is transferred to a holding tank and then pumped into 55 gallon drums. When the water main broke, a truck driver was adding the water from the bottom of the tank truck instead of the top, and sodium hydroxide back- siphoned into the water main.

water ser

vice Hose with bottom fill

Automobile antifreeze Backsiphonage added to boiler water (reverse flow)

Normal flow Water main Curb stop with stop and waste drain

Water main break and repair

“Burned in the shower”

CHAPTER TWO • 3 Salty Drinks Paraquat in the Water System

n January, 1981, a nationally • A backflow preventer ellow gushy stuff ” water supply piping had been I known fast food restaurant that had been installed on the “Y poured from some of left open. A lethal cross- located in southeastern United service line to the shipyard had the faucets in a small town in connection had been created States, complained to the water frozen and had been replaced Maryland, and the State of that permitted the herbicide to department that all their soft with a spool piece sleeve. Maryland placed a ban on flow into the potable water drinks were being rejected by • The shipyard fire drinking the water supply. supply system. Upon restora- their customers as tasting protection system utilized sea Residents were warned not to tion of water pressure, the “salty.” This included soda water that was pumped by both use the water for cooking, herbicides flowed into the many fountain beverages, coffee, electric and diesel driven bathing, drinking or any other faucets and outlets on the town orange juice, etc. An investiga- pumps. purpose except for flushing water distribution system. tion revealed that an adjacent toilets. This cross-connection • The pumps were primed water customer complained of The incident drew wide- created a needless and costly by potable city water. salty water occurring simulta- spread attention and made the event that fortunately did not neously with the restaurant With the potable priming local newspapers. In addition to result in serious illness or loss of incident. This second complaint line left open and the pumps being the lead story on the life. Door-to-door public came from a water front ship maintaining pressure in the fire ABC news affiliate in Washing- notification, extensive flushing, repair facility that was also lines, raw salt water was ton, D.C. and virtually all the water sample analysis, emer- being served by the same water pumped through the priming Washington/Baltimore news- gency arrangements to provide main lateral. The (investigation lines, through the spool sleeve papers that evening. The news temporary potable water from centered on the ship repair piece, to the ship repair facility media contended that lethal tanker trucks, all contributed to facility and revealed the and the restaurant. pesticides may have contami- an expensive and unnecessary following: nated the water supply and town burden. among the contaminants was paraquat, a powerful agricul- tural herbicide. The investigation disclosed that the water pressure in the town water mains was tempo- rarily reduced due to a water Backflow preventer pump failure in the town water replaced by spool piece supply pumping system. Coincidentally, a gate valve Mixing Sink between a herbicide chemical holding tank and the town

Main fresh water line

Pump prime line Herbicide holding tank

High pressure fire line Seawater

Salt water suction line for fire protection Potable town water

Recommended installation of backflow preventer

4 • CROSS-CONNECTION CONTROL MANUAL Propane Gas in the Chlordane and Water Mains Heptachlor at the Housing Authority he services to seventy five of the gate valve. When the Tapartments housing workman cut the 6-inch line, approximately three hundred water started to drain out of the Fire Hose used for people were contaminated with cut, thereby setting up a propane tank chlordane and heptachlor in a backsiphonage condition. As a purging cross city in Pennsylvania, in Decem- result, the chemicals were connected to private ber, 1980. The insecticides siphoned out of the truck, fire hydrant entered the water supply through the garden hose, and system while an exterminating into the system, contaminating company was applying them as the seventy five apartments. a preventative measure against Repeated efforts to clean Recommended backflow termites. While the pesticide and flush the lines were not preventer contractor was mixing the satisfactory and it was finally installation chemicals in a tank truck with decided to replace the water water from a garden hose line and all the plumbing that Water main coming from one of the was affected. There were no pressure apartments, a workman was reports of illness, but residents 65 psi cutting into a 6-inch main line of the housing authority were to install a gate valve. The end told not to use any tap water Explosion of the garden hose was sub- for any purpose and they were merged in the tank containing given water that was trucked undreds of people were ate repair procedures. To the pesticides, and at the same into the area by volunteer fire H evacuated from their start the repair, the tank was time, the water to the area was department personnel. They homes and businesses on an “purged” of residual propane shut off and the lines being were without their normal August afternoon in a town in by using water from one of two drained prior to the installation water supply for 27 days. Connecticut in 1982 as a result private fire hydrants located on of propane entering the city the property. Water purging water supply system. Fires were is the preferred method of reported in two homes and the purging over the use of carbon town water supply was con- dioxide since it is more positive taminated. One five-room and will float out any sludge as residence was gutted by a blaze well as any gas vapors. The resulting from propane gas “purging” consisted of hooking “bubbling and hissing” from a up a hose to one of the private Recommended installation bathroom toilet and in another fire hydrants located on the of hose bibb vacuum breaker home a washing machine property and initiating flushing backflow preventer explosion blew a woman procedures. against a wall. Residents Since the vapor pressure of throughout the area reported the propane residual in the tank hissing, bubbling noises, was 85 to 90 psi., and the water coming from washing pressure was only 65 to 70 psi., machines, sinks and toilets. propane gas backpressure Faucets sputtered out small backflowed into the water streams of water mixed with main. It was estimated that the gas and residents in the area gas flowed into the water mains were asked to evacuate their for about 20 minutes and that Gate valve closed homes. about 2,000 cubic feet of gas This near-disaster occurred was involved. This was approxi- in one, 30,000 gallon capacity mately enough gas to fill one liquid propane tank when the mile of an 8-inch water main. gas company initiated immedi-

CHAPTER TWO • 5 Boiler Water Pesticide in Car Wash Water Enters High School Drinking Water in the Water Main Drinking Water Street pesticide contaminated a his car wash cross- ANorth Carolina water Tconnection and back- Water cooler system in April, 1986, prompt- pressure incident, which High School ing the town to warn residents occurred in February, 1979, of 23 households not to drink in the state of Washington, the water. The residents in the resulted in backflow chemical Bubbler affected area were supplied contamination of approximately drinking water from a tank 100 square blocks of water Bubbler truck parked in the parking lot mains. Prompt response by the Recommended installation of a downtown office building water department prevented a Street of backflow preventer Leaky check valves until the condition could be potentially hazardous water cleared up. Residents com- quality degradation problem plained of foul smelling water without a recorded case of but there were no reports of illness. Toxic rust inhibitor and illness from ingesting the water Numerous complaints of defoamant containing that had been contaminated grey-green and “slippery” water sodium dichromate with a pesticide containing were received by the water chlordane and heptachlor. department coming from the Pump Authorities stated that the same general area of town. A problem occurred when a water sample brought to the water main broke at the same time department by a customer High school boilers that a pest control service was confirmed the reported problem filling a pesticide truck with and preliminary analysis water. The reduction in pressure indicated contamination with high school in New No students or faculty caused the pesticide from inside what appeared to be a deter- Mexico, was closed for were known to have consumed A the tank to be sucked into the gent solution. While emergency several days in June 1984 when any of the water; however, area building’s water main. The crews initiated flushing opera- a home economics teacher physicians and hospitals advised pesticide contaminated the tions, further investigation noticed the water in the potable that if anyone had consumed potable water supply of the within the contaminated area system was yellow. City those high levels of chromium, office building and neighbor- signaled the problem was chemists determined that the symptoms would be nausea, hood area. probably caused by a car wash, samples taken contained levels diarrhea, and burning of the of chromium as high as 700 mouth and throat. Fortunately, parts per million, “astronomi- the home economics teacher, cally higher than the accepted who first saw the discolored levels of .05 parts per million.” water before school started, The head chemist said that it immediately covered all water was miraculous that no one was fountains with towels so that seriously injured or killed by the no one would drink the water. high levels of chromium. The Investigation disclosed chemical was identified as that chromium used in the sodium dichromate, a toxic heating system boilers to inhibit form of chromium used in corrosion of metal parts entered heating system boilers to inhibit the potable water supply corrosion of the metal parts. system as a result of backflow through leaking check valves Recommended installation on the boiler feed lines. of hose bibb vacuum breaker backflow preventer

6 • CROSS-CONNECTION CONTROL MANUAL Shipyard Backflow Contamination or laundry, based upon the • On Monday, February soapy nature of the contami- 12, 1979, the owner repaired nant. The source was quickly the high pressure pump and narrowed down to a car wash resumed normal car wash and the proprietor was ex- operations. The 2-inch hose Potable supply hose tremely cooperative in admit- connection (cross-connection) Shipboard ting to the problem and was not removed! raw water pumping explaining how it had occurred. • Because of the cross- system The circumstances leading up connection, the newly repaired to the incident were as follows: high pressure pump promptly • On Saturday, February pumped a large quantity of To washrooms 10, 1979, a high pressure pump the reclaimed wash/rinse water broke down at the car wash. out of the car wash and into a This pump recycled reclaimed 12-inch water main in the Cafeteria drinking fountains wash and rinse water and street. This in turn was deliv- and sanitation water pumped it to the initial ered to the many residences scrubbers of the car wash. No and commercial establishments To washrooms potable plumbing connection connected to the water main. upply Reduced pressure principle backflow preventers should have been installed is normally made to the car Within 24 hours of the at dockside outlets and other locations wash’s scrubber system. incident, the owner of the car Potable water s • After the pump broke wash had installed a 2-inch down, the car wash owner reduced pressure principle ater fountains at an East The cause of the problem was able to continue operation backflow preventer on his WCoast Shipyard were was a direct cross-connection by connecting a 2-inch hose water service and all car wash posted “No Drinking” as between the on-board salt section temporarily between the establishments in Seattle that workers flushed the water lines water fire protection water potable supply within the car used a wash water reclaim to eliminate raw river water system and the fresh water wash, and the scrubber cycle system were notified of the that had entered the shipyard connected to one of the ships at piping. state requirement for backflow following contamination from the dock. While the shipyard prevention. incorrectly connected water had been aware of the need lines between ships at the pier for backflow protection at the and the shipyard. Some third dockside tie up area, the device shift employees drank the had not been delivered and Wax injectors Soap injectors water before the pollution installed prior to the time of the was discovered and later incident. As a result, the salt Hose connection complained of stomach cramps water on-board fire protection made here and diarrhea. system, being at a greater pressure than the potable supply, forced the salt water, Rinse Rinse through backpressure, into the shipyard potable supply. Scrubbers Fortunately, a small To reclaim tanks demand for potable water at the time of the incident Recommended Recirculating prevented widespread pollution installation of pump in the shipyard and the sur- backflow preventer Reclaim tanks rounding areas. To restrooms

Potable water supply

CHAPTER TWO • 7 Chlordane in the Hexavalent Water Main Chromium in Drinking Water n October, 1979, approxi- end of a garden hose that was n July, 1982, a well meaning and intestinal sickness. Imately three gallons of connected to an outside hose I maintenance mechanic, in Maintenance crews working chlordane, a highly toxic bibb tap in a barrel of diluted attempting to correct a fogging during the plant shutdown insecticide, was sucked back pesticide. During the water lens in an overcooled laser were able to eliminate the cross- (back-siphoned) into the water service interruption, the machine, installed a tempering connection and thoroughly system of a residential area of chlordane solution was back- valve in the laser cooling line, flush the potable water system, a good sized eastern city. siphoned from the barrel and inadvertently set the stage thereby preventing a serious Residents complained that the through the house and into the for a backpressure backflow health hazard from occurring. water “looked milky, felt greasy, water mains. incident that resulted in The incident occurred as foamed and smelled,” and as Following numerous hexavalent chromium contami- follows: one woman put it, “It was complaints, the water depart- nating the potable water of a • Laser machine lenses similar to a combination of ment undertook an extensive large electronic manufacturing were kept cool by circulating kerosene and Black Flag program of flushing of the company in Massachusetts chilled water that came from a pesticide.” water mains and hand delivered employing 9,000 people. large refrigeration chiller. The The problem developed letters telling residents to flush Quantities of 50 parts per water used in the chiller was while water department their lines for four hours before million hexavalent chromium treated with hexavalent personnel were repairing a using the water. Until the water were found in the drinking chromium, a chemical additive water main. A professional lines were clear of the contami- water which is sufficient to used as an anticorrosive agent exterminator, meanwhile, was nant, water was hand-hauled cause severe vomiting, diarrhea, and an algicide. As a result, the treating a nearby home with into homes, and people went chilled water presented a toxic, chlordane for termite elimina- out of their homes for showers, non-potable substance unfit for tion. The workman for the meals and every other activity Hexavalent human consumption but very exterminator company left one involving potable water. chromium added to Fortunately, due to the obvious chilled water bad taste, odor and color of the contaminated water, no one Main plant cooling line consumed a sufficient quantity Laser to endanger health. machine

Temporary chiller Circulating feed pump pumps

Recommended installation of upply backflow preventer CHLORDANE Tempering valve Potable water s

Hot water heater To washrooms Backpressure backflow path To plant bubblers

To ice making machines

To plant vending machines

Recommended installation of hose bibb vacuum breaker backflow preventer

8 • CROSS-CONNECTION CONTROL MANUAL Employee Health Problems due to Cross-Connection acceptable for industrial process cross-connection incident supply line! As the storage tank water. No health hazard was A occurring in a modern pressure increased above the present as long as the piping seven-story office building supply pressure, as a result of was identified, kept separate located in a large city in New thermal expansion, the poten- from potable drinking water Hampshire, in March, 1980, tial for backpressure backflow lines, and not cross-connected resulted in numerous cases of was present. Normally, this to the potable water supply. nausea, diarrhea, loss of time would not occur because a • A maintenance and employee complaints as to boost pump in the supply line mechanic correctly reasoned the poor quality of the water. would keep the supply pressure that by adding a tempering On Saturday, March 1, to the storage tank always valve to the chilled water line, 1980, a large fire occurred two greater than the highest tank he could heat up the water a bit blocks away from a seven-story pressure. The addition of rust and eliminate fogging of the office building in this large inhibiting chemicals to this Roof mounted solar panels laser lenses resulting from the New Hampshire city. On tank greatly increased the chilled water being too cold. Sunday, March 2, 1980, the degree of hazard of the liquid. The problem with the installa- maintenance crew of the office Unfortunately, at the same time tion of the tempering valve was building arrived to perform the that the fire took place, the Utility Heat exchanger that a direct cross-connection weekly cleaning, and after pressure in the water mains was sink had been inadvertently made drinking the water from the reduced to a dangerously low between the toxic chilled water drinking fountains, and pressure and the low pressure and the potable drinking water sampling the coffee from the cutoff switches simultaneously line! coffee machines, noticed that shut off the storage tank • Periodic maintenance the water smelled rubbery and booster pumps. This combina- to the chiller system was had a strong bitter taste. Upon tion allowed the boiler water, performed in the summer, notifying the Manchester Water together with its chemical requiring that an alternate Company, water samples were contaminants, the opportunity Sink chiller feed pump be tempo- taken and preliminary analysis to enter the potable water rarily installed. This replace- disclosed that the contaminants supply within the building. Sink ment pump had an outlet found were not the typical When normal pressure was pressure of 150 psi, and contaminants associated with reestablished in the water Coffee promptly established an fire line disturbances. Investi- mains, the booster pumps machine imbalance of pressure at the gating teams suspected that kicked in, and the contami- tempering valve, thereby over- either the nearby fire could nated water was delivered pressurizing the 60 psi, potable have siphoned contaminants throughout the building. supply. Backpressure backflow from adjacent buildings into the Sink resulted and pushed the toxic water mains, or the contamina- chilled water from the water tion could have been caused by heater and then into the plant’s a plumbing deficiency occurring potable drinking water supply. within the seven story building Chemical Yellowish green water started itself. Water feeder fountatin pouring out of the drinking Water ph levels of the fountains, the washroom, and building water indicated that Booster pump all potable outlets. an injection of chemicals had probably taken place within the Meter seven-story building. Tracing of Water main the water lines within the Recommended installation Backpressure building pinpointed a 10,000 of backflow preventers backflow gallon hot-water storage tank that was used for heat storage in the solar heating system. It did not have any backflow protection on the make-up

CHAPTER TWO • 9 Dialysis Machine Creosote in the Contamination Water Mains

thylene glycol, an anti- potable supply line and fed faucet, which in turn dropped reosote entered the water E freeze additive to air through a manually operated the pressure in the potable C distribution system of a conditioning cooling tower control valve. With this valve supply line to the air condition- southeastern county water water, inadvertently entered the open, or partially open, potable ing holding tank. Since the authority in Georgia, in potable water supply system in make-up water flowed slowly manually operated fill valve was November, 1984, as a result of a medical center in Illinois in into the glycol/water mixture in partially open, this allowed the cross-connection between a September, 1982, and two of the holding tank until it filled glycol/water mixture to enter ¾-inch hose that was being six dialysis patients succumbed to the point where the pressure the medical center potable used as a priming line between as a direct or indirect result of in the closed tank equaled the pipelines and flow into the a fire service connection and the the contamination. pressure in the potable water dialysis equipment. The dialysis suction side of a creosote pump. The glycol was added to supply feed line. As long as the filtration system takes out trace The hose continually supplied the air conditioning water, and potable feed line pressure was at chemicals such as those used in water to the pump to ensure the glycol/water mix was stored least equal to, or greater than, the city water treatment plant, the pump was primed at all in a holding tank that was an the holding tank pressure, no but the system could not times. However, while repairs integral part of the medical backflow could occur. The stage handle the heavy load of were being made to a private center’s air conditioning cooling was set for disaster, however. chemicals that it was suddenly fire hydrant, the creosote back- system. Pressurized make-up It was theorized that subjected to. siphoned into the water mains water to the holding tank was someone in the medical center The effect upon the dialysis and contaminated a section of supplied by a medical center flushed a toilet or turned on a patients was dramatic: patients the water distribution system. became drowsy, confused and Detailed investigation of Glycol/water fell unconscious, and were the cause of the incident pressurized promptly removed to intensive disclosed that the wood Air conditioning units holding tank care where blood samples were preservative company, as part of taken. The blood samples their operation, pumped Submerged inlet revealed a build-up of acid and creosote from collective pits to cross-connection the medical director stated that, other parts of their operation. “Something has happened in The creosote pump would Recommneded installation dialysis.” Dialysis was repeated automatically shut off when the Dialysis room of backflow preventer Slightly open on the patients a second and creosote in the pit was lowered manual third time. to a predetermined level. After Dialysis valve Tests of the water supply to the creosote returned to a filtration unit the filtration system quickly higher level, the pump would determined the presence of “an restart. This pump would lose undesirable chemical in the its prime quite often prior to water purification system.” The the pit refilling, and to prevent Operating room partially open fill valve was the loss of prime, the wood Autopsy then found that it had permit- preservative company would ted the glycol water mix to connect a hose from a ¾-inch Rest Intensive care drain from the air conditioning hose bibb, located on the fire room holding tank into the medical service line, to the suction side center’s potable supply lines of the pump. The hose bibb and then into the dialysis remained open at all times in an filtration system equipment. effort to continuously keep the Washroom pump primed. Backpressure backflow

Main water Boiler supply room Laundry facility Recommended installation of backflow preventer

10 • CROSS-CONNECTION CONTROL MANUAL Kool-Aid Laced With Chlordane

n August, 1978, a profes- The chlordane was quickly Street main Private shut-off Recommended installation I sional exterminator was siphoned into the water lines of backflow preventers treating a church located in a within the church and became Creosote pump Process water small town in South Carolina, mixed with the Kool-Aid being for termite and pest control. prepared by women for the The highly toxic insecticide vacation bible school. Approxi- chlordane was being mixed mately a dozen children and with water in small buckets, three adults experienced Recommended installation and garden hoses were left dizziness and nausea. Fortu- of backflow preventers submerged in the buckets while nately, none required hospital- the mixing was being accom- ization or medical attention. Street main plished. At the same time, water department personnel Creosote contaminated flow came by to disconnect the parsonage’s water line from the church to install a separate water meter for the parsonage. In the process, the water was Recommended installation shut off in the area of the of hose bibb vacuum breaker backflow preventer church building. Since the church was located on a steep hill, and as the remaining water in the lines was used by residents in the area, the church was among the first places to Repairs were necessary to After the repairs were experience a negative pressure. one of the private fire hydrants made to the hydrant, and the on the wood preservative water service restored, the company property, necessitating creosote, now in the fire lines, the shutting down of one of two was forced into the main water service lines and removal of the distribution system. damaged fire hydrant for repair. Since the hydrant was at a significantly lower level than the creosote pit, the creosote back-siphoned through a ¾- inch pump priming hose connecting the creosote pit to the fire service line.

CHAPTER TWO • 11 Chapter Three

Pabsolute = Pgage + 14.7psi Water Pressure Theory of Backflow or For an understanding of the Pgage = Pabsolute – 14.7 psi nature of pressure and its and Backsiphonage In essence then, absolute relationship to water depth, pressure is the total pressure. consider the pressure exerted on Gage pressure is simply the the base of a cubic foot of water pressure read on a gage. If there at sea level. (See Fig. 1) The is no pressure on the gage other average weight of a cubic foot than atmospheric, the gage cross-connection1 is the of water is 62.4 pounds per would read zero. Then the link or channel connecting square foot gage. The base may A absolute pressure would be a source of pollution with a be subdivided into 144-square equal to 14.7 psi which is the potable water supply. The inches with each subdivision atmospheric pressure. polluting substance, in most being subjected to a pressure of The term vacuum indicates cases a liquid, tends to enter the 0.433 psig. that the absolute pressure is less potable supply if the net force Suppose another cubic foot than the atmospheric pressure acting upon the liquid acts in of water were placed directly and that the gage pressure is the direction of the potable on top of the first (See Fig. 2). negative. A complete or total supply. Two factors are therefore The pressure on the top surface vacuum would mean a pressure essential for backflow. First, of the first cube which was of 0 psia or -14.7 psig. Since it there must be a link between originally atmospheric, or is impossible to produce a total the two systems. Second, the 0 psig, would now be 0.433 vacuum, the term vacuum, as resultant force must be toward psig as a result of the super- used in the text, will mean all the potable supply. imposed cubic foot of water. degrees of partial vacuum. In a An understanding of the The pressure of the base of partial vacuum, the pressure principles of backflow and the first cube would also be would range from slightly less backsiphonage requires an increased by the same amount than 14.7 psia (0 psig) to understanding of the terms of 0.866 psig, or two times the slightly greater than 0 psia frequently used in their original pressure. (-14.7 psig). discussion. Force, unless com- Backsiphonage1 results in pletely resisted, will produce fluid flow in an undesirable or motion. Weight is a type of reverse direction. It is caused by FIGURE 1. force resulting from the earth’s atmospheric pressure exerted on Pressure exerted by 1 foot of gravitational attraction. water at sea level. a pollutant liquid forcing it Pressure (P) is a force-per-unit toward a potable water supply area, such as pounds per square system that is under a vacuum. inch (psi). Atmospheric pressure is 62.4#/ft3 Backflow, although literally the pressure exerted by the 12" meaning any type of reversed 12" weight of the atmosphere above flow, refers to the flow produced 12" the earth. by the differential pressure Pressure may be referred to existing between two systems using an absolute scale, pounds both of which are at pressures per square inch absolute (psia), greater than atmospheric. Sea level or gage scale, pounds per square inch gage (psig). 0.433 psig Absolute pressure and gage pressure are related. Absolute pressure is equal to the gage pressure plus the atmospheric pressure. At sea level the atmospheric pressure is 14.7 psia. Thus, 1See formal definition in the glossary of the appendix

12 • CROSS-CONNECTION CONTROL MANUAL If this process were Siphon Theory level exactly balances the because of the partial vacuum repeated with a third cubic foot weight of a column of water created by the drop in pressure. of water, the pressures at the Figure 3 depicts the atmo- 33.9 feet in height. The If the faucet were opened, base of each cube would be spheric pressure on a water absolute pressure within the however, the vacuum would be 1,299 psig, 0.866 psig, and surface at sea level. An open column of water in Figure 4 at broken and the water level 0.433 psig, respectively. It is tube is inserted vertically into a height of 11.5 feet is equal to would drop to a height of 77 evident that pressure varies the water; atmospheric pres- 9.7 psia. This is a partial feet above the ground. Thus, with depth below a free water sure, which is 14.7 psia, acts vacuum with an equivalent the atmosphere was supporting surface; in general each foot of equally on the surface of the gage pressure of -5.0 psig. a column of water 23 feet high. elevation change, within a water within the tube and on As a practical example, Figure 5 is a diagram of an liquid, changes the pressure by the outside of the tube. assume the water pressure at a inverted U-tube that has been an amount equal to the weight- closed faucet on the top of a filled with water and placed in per-unit area of 1 foot of the FIGURE 3. 100-foot high building to be 20 two open containers at sea level. Pressure on the free surface of a liquid. The rate of increase for liquid at sea level. psig; the pressure on the If the open containers are water is 0.433 psi per foot of ground floor would then be placed so that the liquid levels depth. 63.3 psig. If the pressure at the in each container are at the Frequently water pressure ground were to drop suddenly same height, a static state will is referred to using the terms due to a heavy fire demand in exist; and the pressure at any “pressure head” or just “head,” the area to 33.3 psig, the specified level in either leg of and is expressed in units of feet pressure at the top would be the U-tube will be the same. of water. One foot of head reduced to -10 psig. If the The equilibrium condition would be equivalent to the building water system were is altered by raising one of the pressure produced at the base airtight, the water would containers so that the liquid of a column of water 1 foot in remain at the level of the faucet level in one container is 5 feet depth. One foot of head or 14.7 14.7 psia psia 1 foot of water is equal to 0.433 FIGURE 5. FIGURE 4. sea level Pressure relationships in a psig. One hundred feet of head Effect of evacuating air from a continuous fluid system at the column. is equal to 43.3 psig. same elevation.

FIGURE 2. “Zero” Absolute 4.7 psia Pressure exerted by 2 feet of Pressure water at sea level. If, as shown in Figure 4, the tube is slightly capped and a vacuum pump is used to 0.0 evacuate all the air from the psia sealed tube, a vacuum with a or Vacuum pump

-14.7 '

pressure of 0 psia is created psig 10.3 psia 23 within the tube. Because the 24" pressure at any point in a static 0.433 psig

fluid is dependent upon the '

height of that point above a 10 ' reference line, such as sea level, 39.9 it follows that the pressure 9.7 within the tube at sea level psia or -5.0 psig 14.7 14.7 must still be 14.7 psia. This is psia psia 0.866 psig equivalent to the pressure at the ' Sea Level base of a column of water 33.9 11.5 feet high and with the column 14.7 14.7 psia or open at the base, water would psia 0.0 psig rise to fill the column to a depth Sea level of 33.9 feet. In other words, the 1See formal definition in the glossary of the appendix weight of the atmosphere at sea

CHAPTER THREE • 13 above the level of the other. (See level, since atmosphere cannot shown that as a fluid acceler- FIGURE 9. Dynamically reduced pipe Fig. 6.) Since both containers support a column of water ates, as shown in Figure 8, the pressures. are open to the atmosphere, the greater in height than 33.9 feet. pressure is reduced. As water pressure on the liquid surfaces Figure 7 illustrates how flows through a constriction From pollution To fixture in each container will remain at this siphon principle can be such as a converging section of source 14.7 psia. hazardous in a plumbing pipe, the velocity of the water If it is assumed that a static system. If the supply valve is increases; as a result, the state exists, momentarily, closed, the pressure in the line pressure is reduced. Under such within the system shown in supplying the faucet is less than conditions, negative pressures Figure 6, the pressure in the left the pressure in the supply line may be developed in a pipe. +50 psig tube at any height above the to the bathtub. Flow will occur, The simple aspirator is based free surface in the left container therefore, through siphonage, upon this principle. If this can be calculated. The pressure from the bathtub to the open point of reduced pressure is -10 psig at the corresponding level in the faucet. linked to a source of pollution, right tube above the free surface backsiphonage of the pollutant in the right container may also can occur. FIGURE 7. be calculated. Backsiphonage in a plumbing As shown in Figure 6, the Booster pump system. FIGURE 8. pressure at all levels in the left Negative pressure created by tube would be less than at Valve open constricted flow. corresponding levels in the right flow from the source of pollu- tube. In this case, a static Submerged inlet tion would occur when pressure condition cannot exist because on the suction side of the pump fluid will flow from the higher -10 psig is less than pressure of the pressure to the lower pressure; +30 psig +30 psig pollution source; but this is the flow would be from the backflow, which will be discussed right tank to the left tank. This below. Valve open One of the common arrangement will be recognized The preceding discussion occurrences of dynamically as a siphon. The crest of a Closed supply has described some of the reduced pipe pressures is found siphon cannot be higher than means by which negative on the suction side of a pump. 33.9 feet above the upper liquid pressures may be created and In many cases similar to the one which frequently occur to illustrated in Figure 9, the line produce backsiphonage. In FIGURE 6. The siphon actions cited supplying the booster pump is addition to the negative Pressure relationships in a have been produced by reduced continuous fluid system at undersized or does not have pressure or reversed force different elevations. pressures resulting from a sufficient pressure to deliver necessary to cause difference in the water levels at water at the rate at which the backsiphonage and backflow, two separated points within a pump normally operates. The there must also be the cross- continuous fluid system. rate of flow in the pipe may be connection or connecting link 8.2 psia 10.3 psia Reduced pressure may also increased by a further reduction between the potable water be created within a fluid system in pressure at the pump intake. supply and the source of as a result of fluid motion. One This often results in the creation pollution. Two basic types of of the basic principles of fluid ' of negative pressure at the connections may be created in 10 mechanics is the principle of pump intake. This often results piping systems. These are the ' conservation of energy. Based in the creation of negative 15 solid pipe with valved connec- upon this principle, it may be pressure. This negative pressure tion and the submerged inlet. may become low enough in 14.7 '

5 psia some cases to cause vaporization of the water in the line. Actu- ally, in the illustration shown, 14.7 psia

14 • CROSS-CONNECTION CONTROL MANUAL Figures 10 and 11 illustrate of the installer about the difficult to control are those reversal in differential pressure solid connections. This type of possibility of reversed flow is which are not apparent until a may occur when pressure in the connection is often installed often more difficult. Upon significant change in water level potable system drops, for some where it is necessary to supply questioning, however, many occurs or where a supply may reason, to a pressure lower than an auxiliary piping system from installers will agree that the be conveniently extended below that in the system to which the the potable source. It is a direct solid connection was made the liquid surface by means of a potable water is connected. connection of one pipe to because the sewer is occasion- hose or auxiliary piping. A The most positive method another pipe or receptacle. ally subjected to backpressure. submerged inlet may be created of avoiding this type of Solid pipe connections are Submerged inlets are found in numerous ways, and its backflow is the total or com- often made to continuous or on many common plumbing detection in some of these plete separation of the two intermittent waste lines where fixtures and are sometimes subtle forms may be difficult. systems. Other methods used it is assumed that the flow will necessary features of the fixtures The illustrations included involve the installation of be in one direction only. An if they are to function properly. in part B of the appendix are mechanical devices. All meth- example of this would be used Examples of this type of design intended to describe typical ods require routine inspection cooling water from a water are siphon-jet urinals or water examples of backsiphonage, and maintenance. jacket or condenser as shown in closets, flushing rim slop sinks, showing in each case the nature Dual piping systems are Figure 11. This type of connec- and dental cuspidors. Oldstyle of the link or cross-connection, often installed for extra protec- tion is usually detectable but bathtubs and lavatories had and the cause of the negative tion in the event of an emer- creating a concern on the part supply inlets below the flood pressure. gency or possible mechanical level rims, but modern sanitary failure of one of the systems. FIGURE 10. design has minimized or Fire protection systems are an Valved connections between eliminated this hazard in new Backflow example. Another example is potable water and nonpotable fixtures. Chemical and indus- 1 the use of dual water connec- fluid. trial process vats sometimes Backflow , as described in this tions to boilers. These installa- have submerged inlets where manual, refers to reversed flow tions are sometimes inter- the water pressure is used as an due to backpressure other than connected, thus creating a aid in diffusion, dispersion and siphonic action. Any intercon- health hazard. agitation of the vat contents. nected fluid systems in which The illustrations in part C Even though the supply pipe the pressure of one exceeds the of the appendix depict installa- may come from the floor above pressure of the other may have tions where backflow under the vat, backsiphonage can flow from one to the other as a pressure can occur, describing occur as it has been shown that result of the pressure differen- the cross-connection and the the siphon action can raise a tial. The flow will occur from cause of the reversed flow. liquid such as water almost 34 the zone of higher pressure to Non potable Potable feet. Some submerged inlets the zone of lower pressure. This type of backflow is of concern in buildings where two or more FIGURE 11 piping systems are maintained. Valved connection between The potable water supply is potable water and sanitary sewer. usually under pressure directly from the city water main. Occasionally, a booster pump is City supply Condenser used. The auxiliary system is often pressurized by a centrifical pump, although backpressure may be caused by gas or steam pressure from a boiler. A

Sanitary sewer 1See formal definition in the glossary of the appendix

CHAPTER THREE • 15 Chapter Four

Air Gap (2) The air gap may be easily Methods and Devices defeated in the event that the Air gaps are non-mechanical “2D” requirement was purposely backflow preventers that are or inadvertently compromised. for the Prevention of very effective devices to be used Excessive splash may be encoun- where either backsiphonage or tered in the event that higher Backflow and backpressure conditions may than anticipated pressures or exist. Their use is as old as flows occur. The splash may be a Back-Siphonage piping and plumbing itself, but cosmetic or true potential only relatively recently have hazard—the simple solution standards been issued that being to reduce the “2D” wide choice of devices standardize their design. In dimension by thrusting the Aexists that can be used to general, the air gap must be supply pipe into the receiving prevent backsiphonage and twice the supply pipe diameter funnel. By so doing, the air gap backpressure from adding but never less than one inch. is defeated. contaminated fluids or gases See Figure 12. into a potable water supply (3) At an air gap, we expose the system. Generally, the selection water to the surrounding air FIGURE 12. with its inherent bacteria, dust of the proper device to use is Air gap. based upon the degree of hazard particles, and other airborne posed by the cross-connection. pollutants or contaminants. In addition, the aspiration effect of Additional considerations are Diameter based upon piping size, location, “D” the flowing water can drag down and the potential need to surrounding pollutants into the periodically test the devices to “2D” reservoir or holding tank. insure proper operation. (4) Free chlorine can come out of There are six basic types of treated water as a result of the air devices that can be used to gap and the resulting splash and correct cross-connections: air churning effect as the water gaps, barometric loops, vacuum enters the holding tanks. This breakers—both atmospheric reduces the ability of the water and pressure type, double check to withstand bacteria contamina- with intermediate atmospheric tion during long term storage. An air gap, although an vent, double check valve (5) For the above reasons, air extremely effective backflow assemblies, and reduced pressure gaps must be inspected as preventer when used to prevent principle devices. In general, all frequently as mechanical backsiphonage and backpres- manufacturers of these devices, backflow preventers. They are sure conditions, does interrupt with the exception of the not exempt from an in-depth the piping flow with corre- barometric loop, produce them cross-connection control pro- sponding loss of pressure for to one or more of three basic gram requiring periodic inspec- subsequent use. Consequently, standards, thus insuring the tion of all backflow devices. public that dependable devices air gaps are primarily used at end of the line service where Air gaps may be fabricated are being utilized and marketed. from commercially available The major standards in the reservoirs or storage tanks are desired. When contemplating plumbing components or industry are: American Society purchased as separate units and of Sanitary Engineers ASSE), the use of an air gap, some other considerations are: integrated into plumbing and American Water Works Associa- piping systems. An example of (1) In a continuous piping tion (AWWA), and the Univer- the use of an air gap is shown in system, each air gap requires sity of California Foundation for Figure 13. Cross-Connection Control and the added expense of reservoirs Hydraulic Research. and secondary pumping systems.

16 • CROSS-CONNECTION CONTROL MANUAL FIGURE 13. Atmospheric Vacuum FIGURE 15. FIGURE 16. Air gap in a piping system. Atmospheric vacuum breaker. Atmospheric vacuum breaker Breaker typical installation. These devices are among the Supply piping simplest and least expensive mechanical types of backflow Seal preventers and, when installed properly, can provide excellent protection against back- Tank or reservoir siphonage. They must not be utilized to protect against Not less than 6" Barometric Loop backpressure conditions. Construction consists usually of The barometric loop consists of a polyethylene float which is a continuous section of supply free to travel on a shaft and seal Flow condition piping that abruptly rises to a in the uppermost position height of approximately 35 feet against atmosphere with an and then returns back down to elastomeric disc. Water flow the originating level. It is a loop lifts the float, which then causes in the piping system that the disc to seal. Water pressure effectively protects against keeps the float in the upward backsiphonage. It may not be sealed position. Termination of used to protect against back- the water supply will cause the pressure. disc to drop down venting the FIGURE 17. Atmospheric vacuum breaker in Its operation, in the unit to atmosphere and thereby plumbing supply system. protection against back- opening downstream piping to siphonage, is based upon the atmospheric pressure, thus principle that a water column, preventing backsiphonage. Non flow condition at sea level pressure, will not Figure 15 shows a typical rise above 33.9 feet (Ref. atmospheric breaker. Chapter 3, Fig. 4 Page 13). In general, these devices Figure 16 shows the In general, barometric are available in ½-inch through generally accepted installation loops are locally fabricated, and 3-inch size and must be requirements—note that no are 35 feet high. installed vertically, must not shutoff valve is downstream have shutoffs downstream, of the device that would and must be installed at least FIGURE 14. otherwise keep the atmospheric Barometric loop. 6-inches higher than the final vacuum breaker under constant outlet. They cannot be tested pressure. once they are installed in the Figure 17 shows a typical plumbing system, but are, for installation of an atmospheric the most part, dependable, vacuum breaker in a plumbing trouble-free devices for supply system. backsiphonage protection. ' 35

CHAPTER FOUR • 17 Hose Bibb FIGURE 19. Pressure industrial applications are Typical installation of hose bibb Vacuum Breakers vacuum breaker. Vacuum Breakers shown in Figure 21. Again, these devices may These small devices are a This device is an outgrowth of be used under constant pressure specialized application of the the atmospheric vacuum but do not protect against atmospheric vacuum breaker. breaker and evolved in response backpressure conditions. As a They are generally attached to to a need to have an atmospher- result, installation must be at sill cocks and in turn are ic vacuum breaker that could be least 6- to 12-inches higher connected to hose supplied utilized under constant pressure than the existing outlet. outlets such as garden hoses, and that could be tested in line. A spill resistant pressure slop sink hoses, spray outlets, A spring on top of the disc and Hose bibb vacuum breaker vacuum breaker (SVB) is etc. They consist of a spring float assembly, two added gate available that is a modification loaded check valve that seals valves, test cocks, and an to the standard pressure against an atmospheric outlet additional first check, provided vacuum breaker but specifically when water supply pressure is the answer to achieve this designed to minimize water turned on. Typical construction device. See Figure 20. spillage. Installation and is shown in Figure 18. These units are available in hydraulic requirements are When the water supply is the general configurations as similar to the standard pressure turned off, the device vents to shown in Figure 20 in sizes vacuum breaker and the atmosphere, thus protecting ½-inch through 10-inch and devices are recommended for against backsiphonage condi- have broad usage in the internal use. tions. They should not be used agriculture and irrigation as backpressure devices. Manual market. Typical agricultural and drain options are available, together with tamper-proof versions. A typical installation is FIGURE 20. shown in Figure 19. Pressure vacuum breaker Spring

FIGURE 18. Hose bibb vacuum breaker. Test cock

First check valve

Gate Valve Test cock

Gate Valve

¾ inch thru 2 inches

2½ inches thru 10 inches

18 • CROSS-CONNECTION CONTROL MANUAL Double Check with FIGURE 22. Double Check Valve Double check valve with Intermediate atmospheric vent. A double check valve is Atmospheric Vent 1st check 2nd check essentially two single check The need to provide a compact valves coupled within one body device in ½-inch and ¾-inch and furnished with test cocks pipe sizes that protects against and two tightly closing gate moderate hazards, is capable of valves (See Figure 24). being used under constant The test capability feature pressure and that protects gives this device a big advan- against backpressure, resulted tage over the use of two in this unique backflow independent check valves in preventer. Construction is Vent that it can be readily tested to basically a double check valve determine if either or both having an atmospheric vent check valves are inoperative or fouled by debris. Each check located between the two checks FIGURE 23. (See Figure 22). Typical residential use of double is spring loaded closed and Line pressure keeps the check with atmospheric vent. requires approximately a pound vent closed, but zero supply of pressure to open. pressure or backsiphonage will Automatic feed valve This spring loading Supply open the inner chamber to provides the ability to “bite” atmosphere. With this device, through small debris and still extra protection is obtained seal—a protection feature not through the atmospheric vent prevalent in unloaded swing capability. Figure 23 shows a check valves. Figure 24 shows a typical use of the device on a cross section of double check residential boiler supply line. Drain Boiler valve complete with test cocks. Double checks are commonly Return Air gap used to protect against low to FIGURE 21. medium hazard installations Typical agricultural and industrial application of such as food processing steam pressure vacuum breaker. kettles and apartment projects. They may be used under continuous pressure and protect against both backsiphonage and backpressure conditions.

12" minimum above FIGURE 24. the highest outlet Double check valve.

Hose bibb

At least 6" Process tanks

CHAPTER FOUR • 19 Double Check Detector to insure proper operation of Residential Dual Check It is sized for ½-, ¾-, and Check both the primary checks and 1-inch service lines and is the bypass check valve. In the The need to furnish reliable and installed immediately down- This device is an outgrowth of event of very low fire line water inexpensive backsiphonage and stream of the water meter. The the double check valve and is usage, (theft of water) the low backpressure protection for use of plastic check modules primarily utilized in fire line pressure drop inherent in the individual residences resulted in and elimination of test cocks installations. Its purpose is to bypass system permits the low the debut of the residential dual and gate valves keeps the cost protect the potable supply line flow of water to be metered check. Protection of the main reasonable while providing from possible contamination or through the bypass system. In a potable supply from household good, dependable protection. pollution from fire line chemical high flow demand, associated hazards such as home photo- Typical installations are shown additives, booster pump fire with deluge fire capability, the graph chemicals, toxic insect in Figures 27 and 28. line backpressure, stagnant main check valves open, and garden sprays, termite “black water” that sits in fire permitting high volume, low control pesticides used by lines over extended periods of restricted flow, through the two exterminators, etc., reinforced, time, the addition of “raw” large spring loaded check a true need for such a device. water through outside fire valves. Figure 26 shows a cutaway of pumper connections (Siamese the device. outlets), and the detection of any water movement in the fire FIGURE 26. line water due to fire line Residential dual check. leakage or deliberate water theft. It consists of two, spring loaded check valves, a bypass assembly with water meter and double check valve, and two tightly closing gate valves. See Figure 25. The addition of test cocks makes the device testable

FIGURE 25. Double check detector check.

FIGURE 27. FIGURE 28. Residential installation. Copper horn.

Water meter Residential dual check

1¼" meter thread female inlet with 1" NPT thread female union outlet

Water meter

20 • CROSS-CONNECTION CONTROL MANUAL Reduced Pressure FIGURE 29A. Reduced pressure zone backflow Principle Backflow preventer (¾-inch thru 2-inches). Preventer Maximum protection is achieved against backsiphonage and backpressure conditions utilizing reduced pressure 100 psi 95 psi 94 psi principle backflow preventers. These devices are essentially modified double check valves with an atmospheric vent capability placed between the two checks and designed such that this “zone” between the two checks is always kept at least two pounds less than the supply pressure. With this Supply 60 psi Out 47 psi design criteria, the reduced pressure principle backflow 50 psi preventer can provide protec- tion against backsiphonage and backpressure when both the first and second checks become fouled. They can be used under constant pressure and at high hazard installations. They are FIGURE 29B. furnished with test cocks and Reduced pressure zone backflow preventer (2½-inches thru 10- gate valves to enable testing inches). and are available in sizes ¾-inch through 10 inch. Figure 29A shows typical devices representative of ¾-inch through 2-inch size and Figure 29B shows typical devices representative of 2½-inch through 10-inch sizes.

Reduced pressure zone 1st check valve 2nd check valve

100 psi 94 psi 93 psi

Relief valve (rotated 90˚ for clarity)

CHAPTER FOUR • 21 The principles of operation the pressure increases down- relief valve 3 should remain hazard installations such as of a reduced pressure principle stream from the device, tending fully open to the atmosphere to plating plants, where they backflow preventer are as to reverse the direction of flow, discharge any water which may would protect against primarily follows: check valve 2 closes, preventing be caused to backflow as a backsiphonage potential, car Flow from the left enters backflow. Because all valves result of backpressure and washes where they would the central chamber against the may leak as a result of wear or leakage of check valve 2. protect against backpressure pressure exerted by the loaded obstruction, the protection Malfunctioning of one or conditions, and funeral parlors, check valve 1. The supply provided by the check valves is both of the check valves or relief hospital autopsy rooms, etc. pressure is reduced thereupon not considered sufficient. If valve should always be indi- The reduced pressure principle by a predetermined amount. some obstruction prevents cated by a discharge of water backflow preventer forms the The pressure in the central check valve 2 from closing from the relief port. Under no backbone of cross-connection chamber is maintained lower tightly, the leakage back into circumstances should plugging control programs. Since it is than the incoming supply the central chamber would of the relief port be permitted utilized to protect against high pressure through the operation increase the pressure in this because the device depends hazard installations, and since of the relief valve 3, which zone, the relief valve would upon an open port for safe high hazard installations are the discharges to the atmosphere open, and flow would be operation. The pressure loss first consideration in protecting whenever the central chamber discharged to the atmosphere. through the device may be public health and safety, these pressure approaches within a When the supply pressure expected to average between devices are installed in large few pounds of the inlet pres- drops to the minimum differen- 10 and 20 psi within the quantities over a broad range of sure. Check valve 2 is lightly tial required to operate the normal range of operation, plumbing and water works loaded to open with a pressure relief valve, the pressure in the depending upon the size and installations. Figures 31 and 32 drop of 1 psi in the direction of central chamber should be flow rate of the device. show typical installations of flow and is independent of the atmospheric. If the inlet Reduced pressure principle these devices on high hazard pressure required to open the pressure should become less backflow preventers are installations. relief valve. In the event that than atmospheric pressure, commonly installed on high

FIGURE 30. FIGURE 31. Reduced pressure zone backflow Plating plant installation. preventer — principle of operation.

1 2

3 Direction Meter of flow Reversed direction of flow Reduced pressure principle backflow preventer er main Wat

FIGURE 32. Car wash installation.

Reduced pressure principle backflow preventer

Main

22 • CROSS-CONNECTION CONTROL MANUAL FIGURE 33. FIGURE 34. Typical bypass configuration Typical installation reduced reduced pressure principle pressure principle device devices horizontal illustration.

Reduced pressure Reduced pressure Air gap principle device principle device

Drain

Water meter Air gap

Drain 12" min. 30" max.

Note: Device to be set 12" minimum from wall. Reduced pressure principle device

Air gap

FIGURE 35. Drain Typical installation reduced pressure principle device vertical Note: Devices to be set a min. of 12" and a max. of 30" from the floor and 12" from any wall. illustration.

Typical fire line installation double check valve vertical installation.

Reduced pressure principle device

Elbow Siamese Air gap check Siamese Alarm check fitting Drain

Grade

Double check Water meter valve

Note: (1) Refer to manufacturers installation data for vertical mount. (2) Unit to be set at a height to permit ready access for testing and service. (3) Vertical installation only to be used if horizontal installation cannot be achieved. OS&Y gate valve

Fire pipe

CHAPTER ONE • 23 FIGURE 36. FIGURE 37. Typical installation double check Typical installation residential dual valve horizontal and vertical check with straight set and installation. copperhorn.

Double check valve

Water meter Water meter Residential dual check valve 12" min. 30" max.

¾" ball valve

Double check valve

Residential dual check (unit to be set at a height that permits ready access for testing and service)

Copperhorn with Copperhorn with water meter water meter

¾" ball valve

¾" K-copper

Note: Vertical installation only to be used if horizontal installation cannot be achieved.

24 • CROSS-CONNECTION CONTROL MANUAL Chapter Five

Testing Procedures for Backflow Preventers

rior to initiating a test of connections existed which 5. Shut off the downstream Pany backflow device, it is would contaminate the building (number 2) shut-off valve. (Ref. recommended that the follow- water supply system. In order Item (1) above.) ing procedures be followed: to address this situation, it is 6. Wait several moments prior recommended that the owner 1. Permission be obtained from to hooking up the test kit hoses caution the inhabitants of the the owner, or his representative, when testing a reduced pressure building not to use the water to shut down the water supply. principle device. If water exits until the backflow test is This is necessary to insure that the relief valve, in all likelihood, completed and the water since all testing is accomplished the first check valve is fouled pressure restored. Additional under no-flow conditions, the and it is impractical to proceed options available to the building owner is aware that his water with the testing until the valve owner would be the installation supply will be temporarily shut is serviced. This waiting period of two backflow devices in off while the testing is being is not necessary when testing parallel that would enable a performed. Some commercial double check valves. protected bypass flow around and industrial operations 7. Hook up the test kit hoses in the device to be tested. Also, if require constant and uninter- the manner appropriate to the all water outlets are protected rupted water supplies for device being tested and the within the building with cooling, boiler feed, seal pump specific test being performed. “fixture outlet protection” water, etc. and water service backflow devices, cross- Test personnel are cau- interruption cannot be tolerat- connections would not create a tioned to be aware and follow ed. The water supply to problem in the event of local municipal, county, and hospitals and continuous potential backsiphonage state testing requirements and process industries cannot be conditions occurring while guidelines as may be dictated shut off without planned and devices are tested, or for any by local authority. The follow- coordinated shut downs. The other reason. ing test procedures are guide- request to shut down the water lines for standard, generally 2. Determine the type of device supply is therefore a necessary acceptable test procedures to be tested i.e., double check prerequisite to protect the but may be amended, superced- valve or reduced pressure customer as well as limit the ed, or modified by local principle device. liability of the tester. jurisdiction. Concurrent with the 3. Determine the flow direc- request for permission to shut tion. (Reference directional flow off the water, it is advisable to arrows or wording provided by point out to the owner, or his the manufacturer on the representative, that while the device.) water is shut off during the test 4. Number the test cocks, bleed period, any inadvertent use of them of potential debris, and water within the building will assemble appropriate test cock reduce the water pressure to adapters and bushings that may zero. Backsiphonage could be required. result if unprotected cross-

CHAPTER FIVE • 25 Test Equipment

or field testing of reduced FIGURE 38. Method 2 Reduced Pressure Fpressure principle backflow Air inlet valve canopy Using a water column sight Principle Backflow preventers and double check tube and 90 degree elbow Preventer valve assemblies, a differential fitting with bleed needle (Figure 39) pressure test gauge is utilized Loaded air inlet valve Test 1 Test the internal check Field testing of a reduced having a 0 to 15 psi range and valve for tightness of 1 psid in pressure principle backflow a working pressure of 500 psi. Test cock the direction of flow. preventer is accomplished Appropriate length of hoses No. 2 utilizing a differential pressure No. 2 shut off valve 1. Assemble sight tube to test with necessary fittings accom- gauge. The device is tested for cock number 1. Open test pany the test gauge. Several three optional characteristics: Check valve cock and fill the tube to a manufactured test kits are i.e., (1) the first check valve is minimum of 36-inches of commercially available that Test cock tight and maintains a minimum No. 1 shut off valve water height. incorporate the differential No. 1 of 5 psi differential pressure, gauge, hoses, and fittings and 2. Close number 1 shut-off (2) the second check valve is are packaged for ease of valve. tight against backpressure and portability and come with 3. Open test cock number 2. (3) the relief valve opens at a protective enclosures or straps The air inlet valve should minimum of 2 psi below inlet for hanging. Calibrated water open and discharge water supply pressure. Testing is columns are commercially number 1 shut-off valve through number 2 test performed as follows: available that are portable and open) bleed test cocks cock. Step 1 Test to insure that the come with carrying cases. number 1 and number 2. 4. Open number 1 test cock. first check valve is tight and It is important that all test 2. Hook up the high pressure The sight tube level of maintains a minimum pressure equipment be periodically hose to number 1 test cock water should drop slowly of 5 psi differential pressure. checked for calibration. and the low pressure hose until it stabilizes. This to number 2 test cock. 1. Verify that number 1 shut- point should be a mini- off valve is open. Close 3. Bleed the high pressure mum of 28-inches of water number 2 shut-off valve. Pressure Vacuum hose, and low pressure column which equals 1 psi. Breaker If there is no drainage hose, in that order, and from the relief valve it is (Figure 38) close the test kit needle Test 2 Test the air inlet valve for a breakaway of 1 psi. assumed that the first Field testing of a pressure valves slowly. check is tight. 1. Assemble sight tube to vacuum breaker involves testing 4. Record the differential 2. Close all test kit valves. both the internal spring loaded pressure on the gauge. A test cock number 2. Open soft seated check valve as well reading of 1 psid is test cock number 2 and fill 3. Connect the high pressure as testing the spring loaded air acceptable to insure a tight the tube to a minimum of hose to test cock number 2. inlet valve. The testing must be check valve. 36-inches of water height. 4. Connect the low pressure performed with the device Test 2 Test the air inlet valve 2. Close number 1 shut-off hose to test cock number 3. pressurized and the air inlet for a breakaway of 1 psi. valve. 5. Open test cocks number 2 closed. The number 2 shut-off 1. Connect the high pressure 3. Bleed water slowly from and number 3. valve must also be closed and hose to test cock number 2, the number 2 test cock 6. Open high side bleed the air inlet valve canopy and bleed the high pressure bleed needle and observe needle valve on test kit removed. hose. the water column height as bleeding the air from the it drops. Method 1 2. Shut off number 1 shut-off high hose. Close the high Using a differential pressure valve. 4. At the point when the air side bleed needle valve. inlet valve pops open, gauge 3. Slowly open the bleed valve 7. Open the low side bleed record the height of the needle valve on test kit Test 1 Test the internal check of the test kit, and observe water column. This point and record the psi when bleeding air from the low valve for tightness of 1 psid in should be a minimum of hose. Close the low side the direction of flow. the air inlet poppet opens. 28-inches of water column This should be a minimum bleed needle valve. Record 1. With the valve body under which equals 1psi. of 1 psi. Restore the valve the differential gauge pressure, (number 2 shut- Restore the valve to normal to normal service. pressure. It should be a off valve closed and service. minimum of 5 psid.

26 • CROSS-CONNECTION CONTROL MANUAL FIGURE 39. 3. To check the tightness of This completes the lve lve 1 2 number 2 shut-off valve, standard field test for a reduced leave the hoses hooked up pressure principle backflow the same as at the conclu- preventer. Before removal of the

t cock No. 1 No. 1 shutt cock off vaNo. 2 t cock No. 3 t cock No. 4 No. 2 shut off va Check valve No. Check valve No. sion of Step 2 above, and test equipment, the tester Tes Tes Tes Tes then close test cock should insure that he opens number 2. This stops the number 2 shut-off valve supply of any high pressure thereby reestablishing flow. water downstream of check Also, the test kit should be valve number 2. If the thoroughly drained of all water Bleed needle valves differential pressure gauge to prevent freezing by opening High side Low side reading holds steady, the all control needle valves and hose hose number 2 shut-off valve is bleed needle valves. recorded as being tight. If All test data should be the differential pressure recorded on appropriate forms. gauge drops to zero, the (Ref: sample Page 45) Bypass hose number 2 shut-off valve is Control recorded as leaking. Note: The steps outlined above may needle vary in sequence depending upon local valves With a leaking number 2 regulations and/or preferences. shut-off valve, the device is, in most cases, in a flow condition Step 2 Test to insure that the pressure water downstream and the previous readings taken second check is tight against of check valve number 2.) are invalid. Unless a non-flow backpressure. (Figure 40) If the differential pressure condition can be achieved, 1. Leaving the hoses hooked gauge falls off and water either through the operation of up as in the conclusion of comes out of the relief an additional shut-off down- Step 1 above, connect the valve, the second check is stream, or the use of a tempo- bypass hose to test cock recorded as leaking. If the rary compensating bypass hose, number 4. differential pressure gauge accurate test results will not be remains steady, and no 2. Open test cock number 4, achieved. water comes out of the the high control needle relief valve, the second Step 3 To check that the relief valve and the bypass hose check valve is considered valve opens at a minimum control needle valve on the tight pressure of 2 psi below inlet test kit. (This supplies high pressure. 1. With the hoses hooked up the same as at the conclu- FIGURE 40. sion of Step #2 (3) above, slowly open up the low control needle valve on the test kit and record the differential pressure gauge reading at the point when the water initially starts to Temporary Tee bypass hose drip from the relief valve opening. This pressure reading should not be below 2 psid.

CHAPTER FIVE • 27 Double Check Valve FIGURE 41. Assemblies (Figure 41)

Some field test procedures for No. 1 shut off valve No. 2 shut off valve Check valve No. 1 Check valve No. 2 testing double check valve Test cock No. 1 Test cock No. 2 Test cock No. 3 Test cock No. 4 assemblies require that the number 1 shut-off valve be closed to accomplish the test. This procedure may introduce debris such as rust and tubercu- Bleed needle valves lin into the valve that will impact against check valve High side hose Low side hose number 1 or number 2 and compromise the sealing quality. This potential problem should be considered prior to the Bypass hose selection of the appropriate test Control method. needle Two test methods, one valves requiring closing of the number 1 shut-off valve, and one without this requirement are 7. Record the differential To check tightness of 7. The differential gauge presented below: gauge pressure reading. number 2 shut-off valve, both pressure should read a It should be a minimum the check valves must be tight minimum of 1 psid. Method 1 of 1 psid. and holding a minimum of 8. Open the high side control Utilizing the differential 1 psid. Also, little or no 8. Disconnect the hoses. needle valve and the bypass pressure gauge and not fluctuation of inlet supply hose control needle valve shutting off number 1 shut-off Step 2 Checking check valve pressure can be tolerated. on the test kit. (This valve. Figure 41) number 2. The testing is performed as supplies high pressure Step 1 checking check valve 1. Connect the high hose to follows: water downstream of check number 1 test cock number 3. 1. Connect the high hose to valve number 2). 1. Verify that the number 1 2. Connect the low hose to number 2 test cock. 9. Close test cock number 2. shut-off is open. Shut off test cock number 4. 2. Connect the low hose to (This stops the supply of number 2 shut-off valve. 3. Open test cocks number 3 number 3 test cock. any high pressure water downstream of number 2 2. Connect the high hose to and 4. 3. Connect the bypass hose to check valve), If the test cock number 2. 4. Open high side bleed number 4 test cock. differential pressure gauge 3. Connect the low hose to needle valve on test kit 4. Open test cocks numbers holds steady, the number 2 test cock number 3. bleeding the air from the 2, 3, and 4. shut-off valve is recorded as high hose. Close the high 4. Open test cocks 2 and 3. 5. Open high side bleed being tight. If the differen- side bleed needle valve. 5. Open high side bleed needle valve on test kit tial pressure gauge drops to needle valve on test kit 5. Open low side bleed needle bleeding the air from the zero, the number 2 shut-off bleeding the air from the valve on test kit bleeding high hose. Close the high valve is recorded as leaking. high hose. Close the high the air from the low hose. side bleed needle valve. Close the low side bleed side bleed needle valve. 6. Open low side bleed needle needle valve. 6. Open low side bleed needle valve on test kit bleeding valve on test kit bleeding 6. Record the differential the air from the low hose. the air from the low hose. gauge pressure reading. Close the low side bleed Close the low side bleed It should be a minimum needle valve. needle valve. of 1 psid. 7. Disconnect the hoses.

28 • CROSS-CONNECTION CONTROL MANUAL FIGURE 42. 4. By loosening the low side hose at test cock number 3, lower the pressure in the

No. 1 shut off valve No. 2 shut off valve assembly about 10 psi Check valve No. 1 Check valve No. 2 Test cock No. 1 Test cock No. 2 Test cock No. 3 Test cock No. 4 below normal line conditions. 5. Simultaneously open both needle valves. If the check Individual Bourdon gages mounted on a board valve is holding tight the Duplex gauge high pressure gauge will begin to drop while the low pressure gauge will Bypass hose Bypass hose increase. Close needle valves. If the gauge shows that a small (no more than High side hose Low side hose 5 psi) backpressure is created and held, then the High side hose Low side hose check valve is reported as tight. If the check valve leaks, a pressure differential With a leaking number 2 Method 2 Step 2 checking check valve is not maintained as both shut-off valve, the device is, in Utilizing “Duplex Gauge” or number 2. gauges tend to equalize or most cases, in a flow condition, individual bourdon gauges, Proceed exactly the same move back towards each and the previous test readings requires closing number 1 test procedure as in Step other, then the check valve taken are invalid. Unless a non- shut-off. (Figure 42) number 1, except that the is reported as leaking. flow condition can be achieved, high hose is connected to test With both needle valves Step 1 checking check valve either through the operation of cock number 3 and the low open enough to keep the number 1 an additional shut-off down- hose connected to test cock needles on the gauge stream, or the use of a tempo- 1. Connect the high hose to number 4. stationary, the amount of rary compensating bypass hose, test cock number 2. leakage is visible as the Step 3 accurate test results will not be 2. Connect the low hose to discharge from the achieved. test cock number 3. 1. Open shut-off valve upstream needle valve. number 1 to repressurize This completes the 3. Open test cocks number 2 the assembly. standard field test for a double and number 3. check valve assembly. Prior to 2. Loosely attach the bypass 4. Close number 2 shut-off removal of the test equipment, hose to test cock number 1, valve; then close number 1 the tester should insure that he and bleed from the gauge shut-off valve. opens number 2 shut-off valve through the bypass hose thereby reestablishing flow. All 5. By means of the high side by opening the low side test data should be recorded on needle valve, lower the needle valve to eliminate appropriate forms and the test pressure at test cock trapped air. Close low side kit drained of water. number 2 about 2 psi needle valve. Tighten below the pressure at test bypass hose. Open test cock number 3. If this cock number 1. small difference can be 3. Close number 1 shut-off maintained, then check valve. valve number 1 is reported as “tight”. Proceed to Step number 2. If the small difference cannot be maintained, proceed to Step number 3.

CHAPTER FIVE • 29 Chapter Six Responsibility

nder the provisions of the “containment” theory. This Administration of USafe Drinking Water Act of approach utilizes a minimum of 1974, the Federal Government backflow devices and isolates has established, through the the customer from the water a Cross-Connection EPA (Environmental Protection main. It virtually insulates the Agency), national standards of customer from potentially Control Program safe drinking water. The states contaminating or polluting the are responsible for the enforce- public water supply system. ment of these standards as well While it is recognized that as the supervision of public “containment” does not protect water supply systems and the the customer within his sources of drinking water. The building, it does effectively water purveyor (supplier) is held remove him from possible responsible for compliance to contamination to the public the provisions of the Safe water supply system. If the FIGURE 43. Drinking Water Act, to include water purveyor elects to protect Air conditioning cooling tower a warranty that water quality his customers on a domestic provided by his operation is in internal protective basis and/or conformance with the EPA “fixture outlet protective basis,” FIXTURE standards at the source, and is then cross-connection control OUTLET Post mix delivered to the customer protective devices are placed at PROTECTIVE beverage Reduced pressure zone without the quality being internal high hazard locations as DEVICES machine backflow preventer compromised as a result of its well as at all locations where INTERNAL delivery through the distribu- cross-connections exist at the Backflow preventer PROTECTION with intermediate DEVICES tion system. As specified in the “last free-flowing outlet.” This atmospheric vent Code of Federal Regulations approach entails extensive Laboratory faucet double Reduced (Volume 40, Paragraph 141.2, cross-connective survey work on check valve with pressure zone Section (c)) “Maximum contam- behalf of the water superinten- intermediate vacuum breaker backflow preventer inant level, means the maxi- dent as well as constant policing mum permissible level of a of the plumbing within each contaminant in water which is commercial, industrial and Process tank delivered to the free flowing residential account. In large Laboratory Sinks outlet of the ultimate user of a water supply systems, fixture Reduced public water system, except in outlet protection cross- Atmospheric pressure zone the case of turbidity where the connection control philosophy, vacuum backflow Photo breaker preventer developing maximum permissible level is in itself, is a virtual impossibility equipment measured at the point of entry to achieve and police due to the Dishwasher to the distribution system. quantity of systems involved, Contaminants added to the the complexity of the plumbing Hose Double check valve water under circumstances systems inherent in many vacuum backflow breaker preventer controlled by the user, except industrial sites, and the fact that Cafeteria cooking those resulting from corrosion many plumbing changes are Slop sink kettle of piping and plumbing caused made within industrial and by water quality, are excluded commercial establishments that from this definition.” do not require the water depart- Reduced pressure Reduced pressure Figure 43 depicts several ment to license or otherwise zone backflow Dedicated zone backflow options that are open to a water endorse or ratify when contem- line preventer preventer Boiler purveyor when considering plated or completed. cross-connection protection to In addition, internal Containment device commercial, industrial, and plumbing cross-connection residential customers. He may control survey work is generally elect to work initially on the foreign to the average water

30 • CROSS-CONNECTION CONTROL MANUAL Method of Action

purveyor and is not normally a nature of the facility and its complete cross-connection (5) Equip the water authority portion of his job description or potential impact on the water Acontrol program requires a with backflow device test kits. duties. While it is admirable for system (determine degree of carefully planned and executed (6) Conduct meeting(s) with the water purveyor to accept hazard], personally see actual initial action plan followed by the local plumbing inspection and perform survey work, he cross-connections that could aggressive implementation and people, building inspectors, and should be aware that he runs contaminate the water system, constant follow-up. Proper licensed plumbers in the area the risk of additional liability in and take appropriate action to staffing and education of who will be active in the an area that may be in conflict insure the elimination of the personnel is a requirement to inspection, installations and with plumbing inspectors, cross-connection or the installa- insure that an effective program repair of backflow devices. maintenance personnel and tion of required backflow devices. is achieved. A recommended Inform them of the intent of the other public health officials. To assist the water purvey- plan of action for a cross- program and the part that they Even where extensive or in the total administration connection control program can play in the successful “fixture outlet protection,” of a cross-connection control should include the following implementation of the program. cross-connection control program requires that all public characteristics: (7) Prior to initiating a survey programs are in effect through health officials, plumbing (1) Establish a cross-connection of the established commercial the efforts of an aggressive and inspectors, building managers, control ordinance at the local and industrial installations, thorough water supply cross- plumbing installers, and level and have it approved by prepare a list of these establish- connection control program, maintenance men participate the water commissioners, town ments from existing records, the water authorities should also and share in the responsibility manager, etc., and insure that it then prioritize the degree of have an active “containment” to protect the public health and is adopted by the town or hazard that they present to the program in order to address the safety of individuals from cross- private water authority as a water system, i.e., plating many plumbing changes that connections and contamination legally enforceable document. plants, hospitals, car wash are made and that are inherent or pollution of the public water (2) Conduct public informative facilities, industrial metal within commercial and industri- supply system. meetings that define the finishing and fabrication, al establishments. In essence, proposed cross-connection mortuaries, etc. These will be fixture outlet protection control program, review the the initial facilities inspected for becomes an extension beyond Dedicated Line local cross-connection control cross-connections and will be the “containment” program. ordinance, and answer all followed by less hazardous Also, in order for the Figure 43 also depicts the use questions that may arise installations. supplier of water to provide of a “dedicated” potable water concerning the reason for the maximum protection of the line. This line initiates immedi- (8) Insure that any new program, why and how the water distribution system, ately downstream of the water construction plans are reviewed survey will be conducted, and consideration should be given to meter and is “dedicated” solely by the water authority to assess the potential impact upon the requiring the owner of a for human consumption i.e., the degree of hazard and insure industrial, commercial and premise (commercial, industrial, drinking fountains, safety that the proper backflow residential water customers. or residential) to provide at his showers, eye wash stations, etc. preventer is installed concurrent Have state authorities and the own expense, adequate proof It is very important that this with the potential degree of local press and radio attend the that his internal water system piping be color coded through- hazard that the facility presents. meeting. complies with the local or state out in accordance with local (9) Establish a residential plumbing code(s). In addition, plumbing regulations, flow (3) Place written notices of the backflow protection program that he may be required to install, direction arrows added, and the pending cross-connection will automatically insure that a have tested, and maintain, all piping religiously policed to control program in the local residential dual check backflow backflow protection devices that insure that no cross-connections newspaper, and have the local device is installed automatically at would be required—at his own to other equipment or piping radio station make announce- every new residence. are made that could compro- ments about the program as a expense! (10) As water meters are mise water quality. In the event public service notice. The supplier of water repaired or replaced at residen- should have the right of entry that it is felt that policing of (4) Send employees who will this line cannot be reliably ces, insure that a residential to determine degree of hazard administer the program, to a dual check backflow preventer and the existence of cross- maintained or enforced, the course, or courses, on backflow installation of a containment is set with the new or reworked connections in order to protect tester certification, backflow water meter. Be sure to have the potable water system. By so device on this line should be a survey courses, backflow device consideration. the owner address thermal doing he can assess the overall repair courses, etc. expansion provisions.

CHAPTER SIX • 31 Cross-Connection Control Survey Work (11) Prepare a listing of all ross-connection control connection survey will be of (8) Review with the host what testable backflow devices in the C survey work should only benefit to him. you have found and explain the community and insure that be performed by personnel (3) Ask what processes are findings to him. Inform him they are tested by certified test knowledgeable about commer- involved within the facility and that he will receive a written personnel at the time intervals cial and industrial potential for what purpose potable water report documenting the consistent with the local cross- cross-connections as well as is used, i.e., do the boilers have findings together with a written connection control ordinance. general industrial uses for both chemical additives? Are air recommendation for corrective (12) Prepare and submit potable and process water. If conditioning cooling towers in action. Attempt to answer all testing documentation of “containment” is the prime use with chemical additives? Do questions at this time. Review backflow devices to the State objective of the survey, then they use water savers with the findings with the owner or authority responsible for only sufficient time need be chemical additives? Do they manager if time and circum- monitoring this data. spent in the facility to deter- have a second source of water stances permit. mine the degree of hazard (13) Survey all commercial and (raw water from wells, etc.) in (9) Document all findings and inherent within the facility or industrial facilities and require addition to the potable water recommendations prior to operation. Once this is deter- appropriate backflow protection supply? Does the process water preparing the written report. mined, a judgment can be based upon the containment cross-connect with potentially Include as many sketches or made by the cross-connection philosophy and/or internal hazardous chemical etching photos with the final report as control inspector as to what protection and fixture outlet tanks, etc.? possible. If the located cross type of backflow protective protection. Follow up to insure (4) Request “as-built” engineer- connection(s) cannot be device will be needed at the that the recommended devices ing drawings of the potable eliminated, state the generic potable supply entrance, or are installed and tested on both water supply in order to trace type of backflow preventer immediately downstream of the an initial basis and a periodic out internal potable lines and required at each cross connec- water meter. In the event that basis consistent with the cross- potential areas of cross- tion found. the cross-connection control connection control ordinance. connections. (10) Consider requiring or program requires “total” recommending compliance of The surveys should be protection to the last free (5) Initiate the survey by the survey findings within a conducted by personnel flowing outlet, then the survey starting at the potable entrance definitive time frame. (if experienced in commercial and must be conducted in depth to supply (the water meter in most appropriate authority is in industrial processes. The owners visually inspect for all cross- cases) and then proceed with effect). or owners representatives, connections within the facility the internal survey in the event should be questioned as to what and make recommendations that total internal protective the water is being used for in and requirements for fixture devices and fixture outlet the facility and what hazards outlet protective devices, protective devices are desired. the operations may present to internal protective devices, and (6) Survey the plant facilities the water system (both within containment devices. with the objective of looking for the facility and to the water It is recommended that cross-connections at all potable distribution system) in the consideration be given to the water outlets such as: event that a backsiphonage or following objectives when Hose bibbs backpressure condition were to performing a cross-connection Slop sinks exist concurrent with a non- control survey: Wash room facilities protected cross-connection. In (1) Determine if the survey will Cafeteria and kitchens the event that experienced be conducted with a pre- Fire protection and survey personnel are not arranged appointment or Siamese outlets available within the water unannounced. Irrigation outlets authority to conduct the survey, Boiler rooms consideration should be given (2) Upon entry, identify Mechanical room to having a consulting firm yourself and the purpose of the Laundry facilities perform the survey on behalf of visitation and request to see the (hospitals) the water department. plant manager, owner, or maintenance supervisor in order Production floor to explain the purpose of the (7) Make a sketch of all areas visit and why the cross- requiring backflow protection devices.

32 • CROSS-CONNECTION CONTROL MANUAL Chapter Seven

Cross-Connection Control and Backflow CROSS CONNECTION CONTROL Prevention Program MODEL PROGRAM

he successful promotion of 1. Authority for establish- WATER DEPARTMENT NAME Ta cross-connection control ment of a program. ADDRESS and backflow prevention 2. Technical provisions program in a municipality relating to eliminating will be dependent upon legal backflow and cross- authority to conduct such a connections. program. Where a community 3. Penalty provisions for has adopted a modern plumb- DATE violations. ing code, such as the National The following model Plumbing Code, ASA A40.8- program is suggested for 1955, or subsequent revisions municipalities who desire to Approved ______thereof, provisions of the code adopt a cross-connection will govern backflow and control ordinance. Communi- Date ______cross-connections. It then ties adopting ordinances should remains to provide an ordinance check with State health officials that will establish a program to assure conformance with of inspection for an elimination State codes. The form of the of cross- and backflow connec- ordinance should comply with tions within the community. Water Department Name local legal requirements and Frequently authority for such Cross-Connection Control Program receive legal adoption from the a program may already be community. possessed by the water depart- I. Purpose ment or water authority. In A. To protect the public potable water supply served by the such cases no further document ( ) Water Department from the possibility of contamination may be needed. A cross- or pollution by isolating, within its customers internal distribution connection control ordinance system, such contaminants or pollutants which could backflow or should have at least three back-siphon into the public water system. basic parts. B. To promote the elimination or control of existing cross- connections, actual or potential, between its customers in-plant potable water system, and non-potable systems. C. To provide for the maintenance of a continuing program of cross-connection control which will effectively prevent the contamination or pollution of all potable water systems by cross- connection. II. Authority A. The Federal Safe Drinking Water Act of 1974, and the statutes of the State of ( ) Chapters ( ) the water purveyor has the primary responsibility for preventing water from unapproved sources, or any other substances, from entering the public potable water system. B. ( ) Water Department, Rules and Regulations, adopted.

CHAPTER SEVEN • 33 III. Responsibility D.3 Barometric Loop The Director of Municipal Services shall be responsible for the A fabricated piping arrangement rising at least thirty five (35) protection of the public potable water distribution system from feet at its topmost point above the highest fixture it supplies. It is contamination or pollution due to the backflow or backsiphonage utilized in water supply systems to protect against backsiphonage. of contaminants or pollutants through the water service connec- D.4 Double Check Valve Assembly tion. If, in the judgment of the Director of Municipal Services, an An assembly of two (2) independently operating spring loaded approved backflow device is required at the city’s water service check valves with tightly closing shut off valves on each side of the connection to any customer’s promises, the Director, or his check valves, plus properly located test cocks for the testing of each delegated agent, shall give notice in writing to said customer to check valve. install an approved backflow prevention device at each service connection to his premises. The customer shall, within 90 days D.5 Double Check Valve with Intermediate Atmospheric Vent install such approved device, or devices, at his own expense, and A device having two (2) spring loaded check valves separated failure or refusal, or inability on the part of the customer to install by an atmospheric vent chamber. said device or devices within ninety (90) days, shall constitute a D.6 Hose Bibb Vacuum Breaker ground for discontinuing water service to the premises until such A device which is permanently attached to a hose bibb and device or devices have been properly installed. which acts as an atmospheric vacuum breaker. IV. Definitions D.7 Pressure Vacuum Breaker A. Approved A device containing one or two independently operated spring Accepted by the Director of Municipal Services as meeting an loaded check valves and an independently operated spring loaded applicable specification stated or cited in this regulation, or as air inlet valve located on the discharge side of the check or checks. suitable for the proposed use. Device includes tightly closing shut-off valves on each side of the check valves and properly located test cocks for the testing of the B. Auxiliary Water Supply check valve(s). Any water supply, on or available, to the premises other than D.8 Reduced Pressure Principle Backflow Preventer the purveyor’s approved public potable water supply. An assembly consisting of two (2) independently operating C. Backflow approved check valves with an automatically operating differential The flow of water or other liquids, mixtures or substances, relief valve located between the two (2) check valves, tightly under positive or reduced pressure in the distribution pipes of a closing shut-off valves on each side of the check valves plus potable water supply from any source other than its intended properly located test cocks for the testing of the check valves and source. the relief valve. D. Backflow Preventer D.9 Residential Dual Check A device or means designed to prevent backflow or An assembly of two (2) spring loaded, independently operat- backsiphonage. Most commonly categorized as air gap, reduced ing check valves without tightly closing shut-off valves and test pressure principle device, double check valve assembly, pressure cocks. Generally employed immediately downstream of the water vacuum breaker, atmospheric vacuum breaker, hose bibb vacuum meter to act as a containment device. breaker, residential dual check, double check with intermediate E. Backpressure atmospheric vent, and barometric loop. A condition in which the owners system pressure is greater D.1 Air Gap than the suppliers system pressure. A physical separation sufficient to prevent backflow between F. Backsiphonage the free-flowing discharge end of the potable water system and any other system. Physically defined as a distance equal to twice the The flow of water or other liquids, mixtures or substances into diameter of the supply side pipe diameter but never less than one the distribution pipes of a potable water supply system from any (1) inch. source other than its intended source caused by the sudden reduction of pressure in the potable water supply system. D.2 Atmospheric Vacuum Breaker G. Commission A device which prevents backsiphonage by creating an atmospheric vent when there is either a negative pressure or The State of ( ) Control Commission. subatmospheric pressure in a water system.

34 • CROSS-CONNECTION CONTROL MANUAL H. Containment V. Administration A method of backflow prevention which requires a backflow A. The Department will operate a cross-connection control prevention preventer at the water service entrance. program, to include the keeping of necessary records, which fulfills I. Contaminant the requirements of the Commission’s Cross-Connection Regula- A substance that will impair the quality of the water to a tions and is approved by the Commission. degree that it creates a serious health hazard to the public leading B. The Owner shall allow his property to be inspected for possible to poisoning or the spread of disease. cross-connections and shall follow the provisions of the J. Cross-Connection Department’s program and the Commission’s Regulations if a cross-connection is permitted. Any actual or potential connection between the public water supply and a source of contamination or pollution. C. If the Department requires that the public supply be protected by containment, the Owner shall be responsible for water quality K. Department beyond the outlet end of the containment device and should utilize City of ( ) Water Department. fixture outlet protection for that purpose. L. Fixture Isolation He may utilize public health officials, or personnel from the A method of backflow prevention in which a backflow Department, or their delegated representatives, to assist him in the preventer is located to correct a cross connection at an in-plant survey of his facilities and to assist him in the selection of proper location rather than at a water service entrance. fixture outlet devices, and the proper installation of these devices. M. Owner VI. Requirements Any person who has legal title to, or license to operate or A. Department habitat in, a property upon which a cross-connection inspection is to be made or upon which a cross-connection is present. 1. On new installations, the Department will provide on- site evaluation and/or inspection of plans in order to determine N. Person the type of backflow preventer, if any, that will be required, will Any individual, partnership, company, public or private issue permit, and perform inspection and testing. In any case, a corporation, political subdivision or agency of the State Depart- minimum of a dual check valve will be required in any new ment, agency or instrumentality or the United States or any other construction. legal entity. 2. For premises existing prior to the start of this program, O. Permit the Department will perform evaluations and inspections of plans A document issued by the Department which allows the use of and/or premises and inform the owner by letter of any corrective a backflow preventer. action deemed necessary, the method of achieving the correction, and the time allowed for the correction to be made. Ordinarily, P. Pollutant ninety (90) days will be allowed, however, this time period may be A foreign substance, that if permitted to get into the public shortened depending upon the degree of hazard involved and the water system, will degrade its quality so as to constitute a moder- history of the device(s) in question. ate hazard, or impair the usefulness or quality of the water to a 3. The Department will not allow any cross-connection to degree which does not create an actual hazard to the public health remain unless it is protected by an approved backflow preventer for but which does adversely and unreasonably effect such water for which a permit has been issued and which will be regularly tested domestic use. to insure satisfactory operation. Q. Water Service Entrance 4. The Department shall inform the Owner by letter, of That point in the owners water system beyond the sanitary any failure to comply, by the time of the first re-inspection. The control of the District; generally considered to be the outlet end of Department will allow an additional fifteen (15) days for the the water meter and always before any unprotected branch. correction. In the event the Owner fails to comply with the necessary correction by the time of the second re-inspection, the R. Director of Municipal Services Department will inform the Owner by letter, that the water The Director, or his delegated representative in charge of the service to the Owner’s premises will be terminated within a ( ) Department of Municipal Services, is invested with the period not to exceed five (5) days. In the event that the Owner authority and responsibility for the implementation of a cross- informs the Department of extenuating circumstances as to why connection control program and for the enforcement of the the correction has not been made, a time extension may be provisions of the Ordinance. granted by the Department but in no case will exceed an addi- tional thirty (30) days.

CHAPTER SEVEN • 35 5. If the Department determines at any time that a serious VII.Degree of Hazard threat to the public health exists, the water service will be termi- The Department recognizes the threat to the public water nated immediately. system arising from cross-connections. All threats will be classified 6. The Department shall have on file, a list of Private by degree of hazard and will require the installation of approved Contractors who are certified backflow device testers. All charges reduced pressure principle backflow prevention devices or double for these tests will be paid by the Owner of the building or check valves. property. 7. The Department will begin initial premise inspections to VIII. Permits determine the nature of existing or potential hazards, following the The Department shall not permit a cross-connection within approval of this program by the Commission, during the calendar the public water supply system unless it is considered necessary and year ( ). Initial focus will be on high hazard industries and that it cannot be eliminated. commercial premises. A. Cross-connection permits that are required for each B. Owner backflow prevention device are obtained from the Department. A fee of ( ) dollars will be charged for the initial permit and 1. The Owner shall be responsible for the elimination or ( ) dollars for the renewal of each permit. protection of all cross-connections on his premises. B. Permits shall be renewed every ( ) years and are 2. The Owner, after having been informed by a letter from non-transferable. Permits are subject to revocation and become the Department, shall at his expense, install, maintain, and test, or immediately revoked if the Owner should so change the type of have tested, any and all backflow preventers on his premises. cross-connection or degree of hazard associated with the service. 3. The Owner shall correct any malfunction of the backflow C. A permit is not required when fixture isolation is achieved preventer which is revealed by periodic testing. with the utilization of a non-testable backflow preventer. 4. The Owner shall inform the Department of any proposed or modified cross-connections and also any existing cross- IX. Existing in-use backflow prevention devices. connections of which the Owner is aware but has not been found Any existing backflow preventer shall be allowed by the by the Department. Department to continue in service unless the degree of hazard is 5. The Owner shall not install a bypass around any backflow such as to supercede the effectiveness of the present backflow preventer unless there is a backflow preventer of the same type on preventer, or result in an unreasonable risk to the public health. the bypass. Owners who cannot shut down operation for testing of Where the degree of hazard has increased, as in the case of a the device(s) must supply additional devices necessary to allow residential installation converting to a business establishment, any testing to take place. (Ref. Fig. 33 page 23.) existing backflow preventer must be upgraded to a reduced 6. The Owner shall install backflow preventers in a manner pressure principle device, or a reduced pressure principle device approved by the Department. (Ref. Figures 3 through 37, pages 23 must be installed in the event that no backflow device was present. through 24.) 7. The Owner shall install only backflow preventers ap- X. Periodic Testing proved by the Department or the Commission. A. Reduced pressure principle backflow devices shall be 8. Any Owner having a private well or other private water tested and inspected at least semi-annually. source, must have a permit if the well or source is cross-connected B. Periodic testing shall be performed by the Department’s to the Department’s system. Permission to cross-connect may be certified tester or his delegated representative. This testing will be denied by the Department. The Owner may be required to install done at the owner’s expense. a backflow preventer at the service entrance if a private water C. The testing shall be conducted during the Department’s source is maintained, even if it is not cross-connected to the regular business hours. Exceptions to this, when at the request of Department’s system. the owner, may require additional charges to cover the increased 9. In the event the Owner installs plumbing to provide costs to the Department. potable water for domestic purposes which is on the Department’s D. Any backflow preventer which fails during a periodic side of the backflow preventer, such plumbing must have its own test will be repaired or replaced. When repairs are necessary, backflow preventer installed. upon completion of the repair the device will be re-tested at 10. The Owner shall be responsible for the payment of all fees owners expense to insure correct operation. High hazard situa- for permits, annual or semi-annual device testing, retesting in the tions will not be allowed to continue unprotected if the backflow case that the device fails to operate correctly, and second re- preventer fails the test and cannot be repaired immediately. In inspections for non-compliance with Department or Commission other situations, a compliance date of not more than thirty (30) requirements. days after the test date will be established. The owner is respon-

36 • CROSS-CONNECTION CONTROL MANUAL sible for spare parts, repair tools, or a replacement device. Parallel Addendum installation of two (2) devices is an effective means of the owner insuring that uninterrupted water service during testing or repair 1. Residential dual check of devices and is strongly recommended when the owner desires Effective the date of the acceptance of this Cross-Connection such continuity. (Ref. Fig. 33 page 23.) Control Program for the Town of ( ) all new residential E. Backflow prevention devices will be tested more fre- buildings will be required to install a residential dual check device quently than specified in A. above, in cases where there is a history immediately downstream of the water meter. (Ref. Figure 37 of test failures and the Department feels that due to the degree of page 24.) Installation of this residential dual check device on a hazard involved, additional testing is warranted. Cost of the retrofit basis on existing service lines will be instituted at a time additional tests will be born by the owner. and at a potential cost to the homeowner as deemed necessary by XI. Records and Reports the Department. The owner must be aware that installation of a residential dual A. Records check valve results in a potential closed plumbing system within The Department will initiate and maintain the following: his residence. As such, provisions may have to be made by the 1. Master files on customer cross-connection tests and/or owner to provide for thermal expansion within his closed loop inspections. system, i.e., the installation of thermal expansion devices and/or 2. Master files on cross-connection permits. pressure relief valves. 3. Copies of permits and permit applications. 4. Copies of lists and summaries supplied to the 2. Strainers Commission. The Department strongly recommends that all new retrofit B. Reports installations of reduced pressure principle devices and double check valve backflow preventers include the installation of strainers The Department will submit the following to the Commission. located immediately upstream of the backflow device. The installa- 1. Initial listing of low hazard cross-connections to the State. tion of strainers will preclude the fouling of backflow devices due to 2. Initial listing of high hazard cross-connections to the both foreseen and unforeseen circumstances occurring to the water State. supply system such as water main repairs, water main breaks, fires, 3. Annual update lists of items 1 and 2 above. periodic cleaning and flushing of mains, etc. These occurrences 4. Annual summary of cross-connection inspections to the may “stir up” debris within the water main that will cause fouling State. of backflow devices installed without the benefit of strainers. XII. Fees and Charges The Department will publish a list of fees or charges for the following services or permits: 1. Testing fees 2. Re-testing fees 3. Fee for re-inspection 4. Charges for after-hours inspections or tests.

CHAPTER SEVEN • 37 Appendix A Appendix B

Partial List of Illustrations of Plumbing Hazards Backsiphonage

Fixtures with Direct Sewer, sanitary The following illustrates typical undersized water service line Connections Sewer, storm plumbing installations where reduces the pressure at the Swimming pool backsiphonage is possible. water closets to atmospheric producing a reversal of the flow. Description C. Suggested Correction: The Backsiphonage water connection at the bedpan Air conditioning, air washer Fixtures with wash sink and the sterilizer Air conditioning, chilled water Submerged Inlets Case I (Fig. 44) should be provided with Air conditioning, condenser A. Contact Point: A rubber properly installed backflow water hose is submerged in a bedpan preventers. Description Air line wash sink. Aspirator, laboratory Baptismal fount B. Causes of Reversed Flow: Aspirator, medical Bathtub (I) A sterilizer connected to the Backsiphonage water supply is allowed to cool Aspirator, weedicide and Bedpan washer, flushing rim Case 2 (Fig. 45) without opening the air vent. fertilizer sprayer Bidet As it cools, the pressure within A. Contact Point: A rubber Autoclave and sterilizer Brine tank the sealed sterilizer drops below hose is submerged in a labora- Auxiliary system, industrial Cooling tower atmospheric producing a tory sink. Auxiliary system, surface water Cuspidor vacuum which draws the B. Cause of Reversed Flow: Auxiliary system, unapproved Drinking fountain polluted water into the sterilizer Two opposite multi-story contaminating its contents. (2) buildings are connected to the well supply Floor drain, flushing rim Boiler system The flushing of several flush same water main, which often Garbage can washer valve toilets on a lower floor lacks adequate pressure. The Chemical feeder, pot-type Ice maker which are connected to an building on the right has Chlorinator Laboratory sink, serrated nozzle installed a booster pump. Coffee urn Laundry machine FIGURE 44. Backsiphonage (Case 1). Cooling system Lavatory FIGURE 45. Backsiphonage (Case 2). Dishwasher Lawn sprinkler system Fire standpipe or sprinkler Photo laboratory sink system B Sewer flushing manhole Fountain, ornamental A Slop sink, flushing rim Hydraulic equipment Slop sink, threaded supply Laboratory equipment A Steam table Lubrication, pump bearings Urinal, siphon jet blowout Photostat equipment Vegetable peeler Plumber’s friend, pneumatic Water closet, flush tank, Pump, pneumatic ejector ball cock Pump, prime line Water closet, flush valve, Pump, water operated ejector siphon jet BB

B

38 • CROSS-CONNECTION CONTROL MANUAL When the pressure is inad- Backsiphonage Backsiphonage B. Cause of Reversed Flow: equate in the main, the build- Gasoline may enter the ing booster pump starts Case 4 (Fig. 47) Case 5 (Fig. 48) distribution system by gravity pumping, producing a negative A. Contact Point: The water A. Contact Point: The gasoline or by siphonage in the event of pressure in the main and supply to the dishwasher is not storage tank is maintained full a leak or break in the water causing a reversal of flow in the protected by a vacuum breaker. and under pressure by means of main. opposite building. Also, the dishwasher has a solid a direct connection to the city C. Suggested Correction: A C. Suggested Correction: The waste connection to the sewer. water distribution system. reduced pressure principle laboratory sink water outlet B. Cause of Reversed Flow: backflow preventer should be should be provided with a The undersized main serving installed in the line to the vacuum breaker. The water the building is subject to FIGURE 48. gasoline storage tank or a surge service line to the booster pump reduced pressures, and therefore Backsiphonage (Case 5). tank and pump should be should be equipped with a only the first two floors of the provided in that line. device to cut off the pump building are supplied directly when pressure approaches a with city pressure. The upper negative head or vacuum. floors are served from a booster Backsiphonage pump drawing suction directly Case 6 (Fig. 49) from the water service line. Backsiphonage During periods of low city A. Contact Point: There is a pressure, the booster pump submerged inlet in the second Case 3 (Fig. 46) suction creates negative Gasoline floor bathtub. A A. Contact Point: A chemical pressures in the low system, B. Cause of Reversed Flow: tank has a submerged inlet. thereby reversing the flow. Water An automobile breaks a nearby B. Cause of Reversed Flow: C. Suggested Correction: The fire hydrant causing a rush of The plant fire pump draws dishwasher hot and cold water Main water and a negative pressure in suction directly from the city should be supplied through an B the service line to the house, water supply line which is air gap and the waste from the sucking dirty water out of the insufficient to serve normal dishwasher should discharge bathtub. plant requirements and a major through an indirect waste. The C. Suggested Correction: The fire at the same time. During a booster pump should be hot and cold water inlets to the fire emergency, reversed flow equipped with a low-pressure FIGURE 49. bathtub should be above the may occur within the plant. cutoff device. Backsiphonage (Case 6). rim of the tub. C. Suggested Correction: The water service to the chemical FIGURE 47. tank should be provided Backsiphonage (Case 4). through an air gap. A

FIGURE 46. Backsiphonage (Case 3).

CHEMICALS INC.

B

A Dishwasher A

Sewer

High service Low service B B Main

APPENDIX B • 39 Appendix C

C. Suggested Correction: Illustrations of Each pier water outlet should be protected against backflow. The main water service to the Backpressure pier should also be protected against backflow by an air gap The following presents FIGURE 51. or reduced pressure principle illustrations of typical plumbing Backflow (Case 2). backflow preventer. installations where backflow resulting from backpressure is possible. Backflow B Case 4 (Fig. 53)

Backflow A A. Contact Point: A single- valved connection exists Case I (Fig. 50) between the public, potable A. Contact Point: A direct Backflow water supply and the fire- connection from the city supply Case 2 (Fig. 51) sprinkler system of a mill. to the boiler exists as a safety B. Cause of Reversed Flow: measure and for filling the A. Contact Point: Sewage The sprinkler system is nor- system. The boiler water system seeping from a residential mally supplied from a nearby is chemically treated for scale cesspool pollutes the private Backflow lake through a high-pressure prevention and corrosion well which is used for lawn Case 3 (Fig. 52) pump. About the lake are large control. sprinkling. The domestic water numbers of overflowing septic B. Cause of Reversed Flow: system, which is served from a A. Contact Point: A valve tanks. When the valve is left The boiler water recirculation city main, is connected to the connection exists between the open, contaminated lake water pump discharge pressure or well supply by means of a valve. potable and the non potable can be pumped to the public backpressure from the boiler The purpose of the connection systems aboard the ship. supply. may be to prime the well exceeds the city water pressure B. Cause of Reversed Flow: supply for emergency domestic C. Suggested Correction: The and the chemically treated While the ship is connected to use. potable water supply to the fire water is pumped into the the city water supply system system should be through an air domestic system through an B. Cause of Reversed Flow: for the purpose of taking on gap or a reduced pressure open or leaky valve. During periods of low city water for the potable system, principle backflow preventer C. Suggested Correction: As water pressure, possibly when the valve between the potable should be used. minimum protection two check lawn sprinkling is at its peak, and nonpotable systems is valves in series should be the well pump discharge opened, permitting contami- FIGURE 53. provided in the makeup pressure exceeds that of the city nated water to be pumped into Backflow (Case 4). waterline to the boiler system. main and well water is pumped the municipal supply. An air gap separation or into the city supply through an ACME MILLS reduced pressure principle open or leaky valve. FIGURE 52. backflow preventer is better. C. Suggested Correction: The Backflow (Case 3). connection between the well Sprinkler FIGURE 50. water and city water should be System Backflow (Case 1). broken

City main A A B Pump B

To potable A system B Chemical feeder

40 • CROSS-CONNECTION CONTROL MANUAL Appendix D Appendix E

Illustrations of Illustrations of Air Gaps Vacuum Breakers

The following illustrations describe methods of providing an FIGURE 57. air gap discharge to a waste line which may be occasionally or Vacuum breakers. continuously subject to backpressure. Vaccum closes gate FIGURE 54. Brass inset Air gap to sewer subject to backpressure—force main. Air enters here Air preventing rise of D Rubber sleeve contaminated liquids Ball check in fixtures

2xD

Air vent Waste line Flush connection

Pump Cowl nut

FIGURE 55. Air gap to sewer subject to backpressure—gravity drain.

D FIGURE 58. Vacuum breaker arrangement for 2xD an outside hose hydrant. Indirect waste

“A” “A” Ball check Plan Support vanes

Horizontal waste 1" sleeve, sch. 40. FIGURE 56. ½" or ¾" Fire system makeup tank for a Hand wheel gate valve dual water system. Exterior " " ½ or ¾ building wall I.P.S. hose adapter sch. 40. galv.

½" or ¾" vacuum breaker " " Coupling M.I. galv. Nonpotable supply Float valves Potable supply ½ or ¾ 2xD nipple galv. ½" or ¾" Ell. m. M. I. galv. Section “A” “A”

(By permission of Mr. Gustave J. Angele Sr., P.E. formerly Plant Sanitary Engineer, Union Carbide Nuclear To fire system Division, Oak Ridge, Tenn.)

APPENDIX E • 41 Appendix F

Glossary

Air gap The unobstructed Effective Opening The Plumbing The practice, Vacuum Breaker A device vertical distance through minimum cross-sectional materials, and fixtures that permits air into a the free atmosphere area at the point of water used in the installation, water supply distribution between the lowest supply discharge, measured maintenance, extension, line to prevent opening from any pipe or or expressed in terms of and alteration of all piping, backsiphonage. faucet supplying water to a (1) diameter of a circle, or fixtures, appliances and Water Outlet A discharge tank, plumbing fixture, or (2) if the opening is not appurtenances in connec- opening through which other device and the flood- circular, the diameter of a tion with any of the water is supplied to a level rim of the receptacle. circle or equivalent cross- following: sanitary fixture, into the atmo- Backflow The flow of water or sectional area. drainage or storm drainage sphere (except into an open other liquids, mixtures, or Flood-Level Rim The edge of facilities, the venting tank which is part of the substances into the the receptacle from which system and the public or water supply system), to a distributing pipes of a water overflows. private water-supply boiler or heating system, to systems, within or potable supply of water Flushometer Valve A device any devices or equipment adjacent to any building, from any source or sources which discharges a prede- requiring water to operate structure, or conveyance; other than its intended termined quantity of water but which are not part of also the practice and source. Backsiphonage is to fixtures for flushing the plumbing system. materials used in the one type of backflow. purposes and is actuated by Water Supply System The installation, maintenance, Backflow Connection Any direct water pressure. water service pipe, the extension, or alteration of arrangement whereby water-distributing pipes, Free Water Surface A water storm water, liquid waste, backflow can occur. and the necessary connect- surface that is at atmo- or sewerage, and water- ing pipes, fittings, control Backflow Preventer A device spheric pressure. supply systems of any valves, and all appurte- or means to prevent Frostproof Closet A hopper premises to their connec- nances in or adjacent to backflow. Backflow with no water in the bowl tion with any point of the building or premises. Preventer, Reduced and with the trap and public disposal or other The water supply system Pressure Principle Type water supply control valve acceptable terminal. An assembly of differential is part of the plumbing located below frost line. Potable Water Water free valves and check valves system. Indirect Waste Pipe A drain from impurities present including an automatically pipe used to convey liquid in amounts sufficient to opened spillage port to the wastes that does not cause disease or harmful atmosphere. connect directly with the physiological effects. Backsiphonage Backflow drainage system, but which Its bacteriological and resulting from negative discharges into the chemical quality shall pressures in the distribut- drainage system through conform to the require- ing pipes of a potable water an air break into a vented ments of the USEPA supply. trap or a properly vented National Primary Drink- Cross-Connection Any actual and trapped fixture, ing Water Regulations and or potential connection receptacle, or interceptor. the regulations of the between the public water public health authority supply and a source of having jurisdiction. contamination or pollution. Vacuum Any absolute pressure less than that exerted by the atmosphere.

42 • CROSS-CONNECTION CONTROL MANUAL Appendix G

Bibliography

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M14, American Water Works Certification Training Course, How To Prevent Industrial Cross- Association, Denver, Colorado Public Drinking Water Use of Backflow Preventers for Connection Dangers, Water Cross-Connection Control, Joint 1966. Program, Division of Environ- Works Engineering, Feb. 1962. Committee Report, Journal Backflow Prevention and Cross- mental Quality, Department of Manitoba Plumbing Code 1981, Connection Control, Ohio EPA, Natural Resources, State of American Water Works Issued by the Department of , Vol. 50, No.12, Office of Public. Water Supply. Missouri. Association Labour and Manpower of the Dec. 1958. Second Edition, Revised Mar. Cross-Connection Control Manual, Province of Manitoba. 15, 1977. Backflow Prevention Division of Sanitary Engineer- Van Meter, R. O., Backflow Manual of Cross-Connection Prevention Hardware, Water and Devices—Selection, Installation, ing, Tennessee Dept. of Public Control, Dept. of Health and Wastes Engineering, Pt. 1, Sept. Maintenance, and Field Testing, Health, 1975. CSA Standard B64.10M1981. Hospitals, Denver, Colorado, 1970; Pt. 2, Oct. 1970. 1977. Canadian Standards Association, Cross-Connection Control Regula- , Dec.1981. tion in Washington State Manual of Cross-Connection Washington State Dept. of , Foundation for Cross- Backflow—The Manual of Cross- Control Social and Health Services, Connection Control and Connection Prevention in Public Denver, Colorado, 1974. Second Hydraulic Research, University Water Supplies, Missouri Dept. of Edition. Natural Resources. of Southern California, 7th Cross-Connection Control, New Editions, June 1985. York State Dept. of Health, Jan.1981.

APPENDIX G • 43 Appendix H

Cross-Connection Survey Form

Date: ______

Name of Company, Corporation, or Business: ______

______

Address: ______

Name of Contact: ______

Type of Use: Industrial ______Commercial ______Governmental ______Other

Location of Service: ______

Size of Service: ______Inch Metered? Yes No

Require non-interrupted water service? Yes No

Does Boiler Feed utilize chemical additives? Yes No

Is Backflow protection incorporated? Yes No

Are air conditioning cooling towers utilized? Yes No

Is Backflow protection incorporated? Yes No

Is a Water Saver utilized on condensing lines or cooling towers? N/A Yes No

Is the make-up supply line backflow protected? Yes No

Is process water in use, and if so, is it potable supply water or “Raw” water N/A Potable Raw Protected Unprotected

Is fire protection water separate from the potable supply? Yes No

Are Containment Devices in place? Yes No

Summary

Degree of Hazard: High Low

Type of Device recommended for containment: RPZ DCV None

Fixture Outlet protection required? Yes No

If so, where? ______

44 • CROSS-CONNECTION CONTROL MANUAL Appendix I Backflow Prevention Device Test and Maintenance Report

To: ______(water purveyor or regulatory agency) ______

______Attn: Cross-connection Control Section

The cross-connection control device detailed hereon has been tested and maintained as required by the (rules or regulations) of (purveyor or regulatory agency) and is certified to comply with these (rules or regulations). Make of device ______size ______Model Number ______located at ______Serial Number ______

Reduced Pressure Devices Pressure Vacuum Breaker Double Check Devices Relief Valve Air Inlet Check Valve 1st Check 2nd Check Opened at ______psid DC - Closed Opened at ______psid Leaked Tight Closed Tight Initial Test ______psid Did not open RP - ______psid Leaked Leaked

Repairs and Materials Used

DC-Closed Tight Closed Tight Opened at Opened at ______psid Test After Repair RP- ______psid ______psid ______psid

The above is certified to be true. Firm Name ______Certified Tester ______Firm Address ______Cert. Tester No. ______Date ______WH-550 Office of Water (4606M) United States EPA 816-R-03-002 Environmental Protection www.epa.gov/safewater Agency February 2003 Washington, DC 20460

Official Business Penalty for Private Use $300