Water Distribution (Source 3) Exam Questions & Answer Already Solved 100%

delivered min. working pressure - Answer 35 PSI RP backflow preventer will stop... - Answer back pressure and back siphon age gate valves have less... - Answer friction loss cavitation is caused by... - Answer excess pump speed hydrant flow - Answer (2.83)(D^2)(l)/(square root of H)=GPM min. distribution pressure - Answer 20 PSI aquifer - Answer water bearing stratum of rock, sand, or gravel type of rupture or breakage that may occur when a pipe is unevenly supported along its length - Answer beam breakage AWWA's max distance between residential valves - Answer 800 ft. min. flushing velocity when unidirectional flushing method - Answer 5 FPS which type of level sensor requires an air supply - Answer bubbler tube MCL for chloride - Answer 250 mg/L two tier 1 violations - Answer acute risk to health purpose for metallic tracer tape - Answer locating protection of distribution pipe min. backflow protection against a cross connection containing a contaminant that is dangerous to health - Answer double check valve assembly reverse water flow caused by a vacuum is called... - Answer back siphon age min. contact time when disinfecting water mains with the chlorine slug method - Answer 3 hours DI pipe primarily used for river crossings and underwater intakes - Answer ball and socket a reduced pressure zone device consists of two spring loaded check valves with a... - Answer pressure regulated relief located between them a venturi meter has... - Answer two taps, the downstream tap is the high pressure tap anodes suspended in a tank are used to prevent... - Answer corrosion min height of well vent pipe - Answer 36 inches test that determines if mains need cleaning or replacement - Answer fire flow test water demand in a community is usually estimated on the basis of - Answer per capita demand valves needed at pipe crosses - Answer three valves needed at pipe tees - Answer two min acceptable CL2residual when using chloramines for disinfection - Answer .6 mg/L CL2 residual needed to disinfect well casings - Answer 50 ml/L backflows are installed downstream from the what - Answer meter double check backflows offer what level of protection - Answer least RP backflows offer what level of protection - Answer medium RP backflows have what between two check valves - Answer relief valve what offers the highest level of backflow protection - Answer air gap min and max distance backflows to be off ground - Answer 12 min 30 inches max what is a more powerful disinfectant than chloramines - Answer chlorine what disinfectant is more persistent than chlorine - Answer chloramines chloramines are more effective than chlorine against what - Answer biofilms main chlorination at 25-50 mg/L is held for how long - Answer 24 hours min CL2 residual for main after 24 hour hold - Answer 10 mg/L main slug method at 100 mg/l must be held for min of - Answer 3 hours calcium hypochlorite can support a fire when stored close to what - Answer organics if CL2 residual leaving plant falls below .20, how long do you have to correct the problem - Answer 4 hours, if corrected under 4 hours not a violation, but regulatory agency must be notified convert F to C - Answer (F-32)/1.8 convert C to F - Answer (C x 1.8) + 32 how many times a day are CL2 residuals taken at small plants - Answer 3 times a day how often are CL2 residuals taken at large plants - Answer every 2 hours CL2 gas is extremely toxic and corrosive in what kind of atmosphere - Answer moist respiratory protection must be certified by what - Answer niosh national institute for occupational safety health when CL2 gas exceeds what level a full face respirator is needed - Answer .5 ppm respiratory protection needed during an uncontrolled release - Answer SCBA how often should reservoirs be inspected - Answer weekly how often should valves be inspected - Answer annually how often should valve boxes be inspected - Answer annually Why should ARV's be inspected after heavy rains or floods - Answer submersion danger what should you do if you suspect reservoir vandalism - Answer shut it down