Back flow test practice test.

Back flow test practice test. what is the difference between check valve 1 and check valve 2 on a double check valve assembly - ANS the two check valves operate the same in a perfect vacuum, water can be drawn up in a column _______ feet - ANS 33.9 which of the following is considered to be a chemical contaminant? - ANS arsenic which of the following is considered to be a biological health hazard - ANS giardia what type of assembly has two internally spring loaded check, two shut-off valves, and four test cocks? - ANS double check valve air gap is the_________ when directly connecting potable water supply lines to sewerage systems or to radioactive sources? - ANS most suitable protection a bypass of a backflow prevention assemble may be permitted only if the assembly in the bypass: - ANS is the same type what federal law made water purveyors responsible for water quality all the way into consumers' homes or businesses? - ANS safe drinking water act amendment of 1986 if a column of water is exerting a pressure of 50 psi, how high must the water be inside the column? - ANS 115.5 as the velocity of water increases, pressure: - ANS decreases atmospheric pressure at sea level is _______ psi - ANS 14.7 a water supply other than the water purveyor's approved supply, that is on or available to the premises is called a - ANS auxiliary water supply how can a backsiphonage action be broken - ANS air gap what single difficult to regulate item is most commonly associated with cross connections, specifically through backsiphonage? - ANS garden house the appropriate height fo an air gap is - ANS twice the diameter of the pipe above the flood rim of vessel, minimum of 1 inch while testing check balbe #1 on a DC, water recedes from the tuve attached to test cock #3. The gauge should be moved to the centerline of the assembly and the static pressure drop across the no. 1 check should be recorded. What other information should be recorded. - ANS check valve #2 is leaking and shutoff valve #2 is leaking at what point is the relief valve in an RP required to open - ANS 2.0 psid what is the minimum spring tension recommended on the #1 check valve in an RPZ - ANS 3 psi greater than the tension on the relief valve. according to the USC, what is the correct height for installing an RPZ - ANS 12 inches above grade, but no more than 36 inches what is the correct height to install a PVB - ANS 12 inches above the highest downstream point. what company or agency is responsible for testing and approving all backflow prevention assemblies in the united states? - ANS foundation of cross-connection control & hydraulic research backflow prevention assemblies are often installed in parallel in order to: - ANS maintain service during testing and repairs which of the following is not a criterion for an approved assembly? - ANS shipped by manufacturer in separate parts for inspection what is the minimum pressure drop across a spring-loaded, soft-seated check valve? - ANS 1.0 psid when testing a double check valve assembly, what is the correct order for closing the shutoff valves? - ANS shutoff #2 , then shutoff #1 where is the relief valve of an RPZ located? - ANS between check valve #1 and check valve #2 an atmospheric vacuum breaker is designed to protect against? - ANS Pollutants & contaminants, but under backsiphonage only backflow prevention by containment means: - ANS placing a backflow preventer at the meter what type of backflow prevention assembly would be recommended in a car wash facility at the service connection to a potable water supply? - ANS RPZ according to the safe Drinking water act, the primary responsibility for preventing water from an unsuitable or unsafe source from entering the public water system lies with the: - ANS water utility supplying the water should a customer refuse to install a backlow prevention device at a service connection where a potential health hazard exits, the water purveyor should have the authority to: - ANS discontinue water service the condition where undersized water pipes carry water under high velocity and may cause a backsipohonage is referred to as the - ANS venturi effect what is the purpose of the 3.0 psi buffer in an RPZ when check valves in other assemblies only require a 1.0 psi static pressure drop across them - ANS to minimize the effects of small fluctuations in line pressure se not to cause the differential pressure relief valve to discharge. which of the following markings is not required for backflow prevention assemblies - ANS minimum working water pressure for proper operation the best place to install a reduced pressure backflow prevention device is; - ANS in an accessible location above grade what protection is equivalent to or better than an RP - ANS approved air-gap separation when should an RP device be tested - ANS at least annually, after installation, and after repairs why do you open then close the test kit low bleed valve before determining the pressure differential across an RP check valve #1 - ANS reestablish "setup pressure" when testing a reduced pressure zone backflow preventer, bleed valves should be opened in which order - ANS low then high what type of gauge is used to measure the pressure across check valves in RP's, DC's, and PVB's - ANS differential when setting up an RP for testing you notice that the gauge dropped to the low end of the scale and that the relief valve began discharging continuously when the no. 2 shutoff valve was closed. what is the probable cause - ANS leaking #1 check valve if you observe the relief valve of an RPZ spitting water, what would be the suspected cause? - ANS line pressure fluctuating. You approach an RP that is dripping. Your first move is to close the no. 2 shutoff valve at which time the relief valve stops dripping. what does this indicate - ANS failing #2 check valve, under backpressure you approach an RP that is dripping and the customer is currently using water. You close the no. 2 shutoff valve and the relief valve continues to leak. what does this indicate? - ANS leaking relief valve under backpressure conditions, the check valves of a double check valve assembly should be - ANS closed atmospheric pressure is defined as - ANS the pressure exerted by the weight of the air upon the earth what would most likely occur, if you switched the spring's on each check valve of an RP assembly - ANS relief valve would discharge continuously while testing a reduce pressure backflow preventer. the tester has determined that the line pressure is 75 psi. the test shows that check valve #1 holds a pressure differential of 7.5, check valve #2 holds a pressure differential of 2.2, and the relief opened at 1.8 psid. what is the line pressure downstream of the RP in a no-flow condition? - ANS 65.3 what are the limitations of an air gap separation? - ANS air gap is easily altered backpressure against cv1 of an RP will cause which of the following: - ANS relief valve to dump static pressure means: - ANS no flow an approved air gap shall be at least ______ the diameter of the supply pipe. - ANS twice the minimum approved air gap is _________ inch(es). - ANS one the term "auxiliary supply" means any water supply on or available to the premises other than the ___ water supply. - ANS public regulations dealing with cross connections require that the backflow prevention device shall be tested at least ________ a year - ANS once the specifications of the 9th edition of the manual for cross connection control calls for the relief valve to be full open when the pressure differential between the "zone" and the upstream line pressure is __________ psi or less. - ANS two the difference between the opening point of the relief valve and the differential across the first check valve should be at least _______ psi to minimize excessive discharges due to pressure fluctuations in the supply line. - ANS three an appropriate application of a reduced pressure backflow preventer would be to provide adequate protection for what type (degree) of haxard? - ANS high hazard what are two backflow conditions that may cause a reversal of flow in water lines? - ANS backsiphonage and backpressure for installations requiring continuous service service lines entering the premises, it is sometimes necessary to install _______ devices. - ANS dual a vacuum breaker should only be used to protect against _________. - ANS backsiphonage only according to usc, what is the correct height to install an atmospheric vacuum breaker? - ANS 6 inches above the highest downstream point test kits should be verified for accuracy and, if needed, calibrated how often? - ANS at least once a year to determine the air inlet opening point on a PVB, the tester must open the: - ANS high side bleed valve backpressure - ANS a form of backflow due to a vacuum or partial vaccum reduced pressure principle assembly - ANS a device consisting of two check valves and a differential relief valve located between the two check valves pressure vacuum breaker - ANS a device having a spring loaded air opening down stream from a single check valve backsiphonage - ANS a form of backflow due to a vacuum or partial vacuum air gap - ANS a physical break between a supply pipe and a receiving vessel atmospheric vacuum breaker - ANS a device consisting of a single check valve and an air opening. device must be installed on the discharge side of the last valve double check valve device - ANS a device consisting of two internally loaded check valves cross connection - ANS any actual or potential connection between a public or private potable water system and any other source through which pollution may enter the potable system.