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water distribution systems are composed of:
service lines
fire hydrants
storage pumps
the most difficult funcition of the distribution system is
the continuous delivery of water
the most important factor affect pressure requirements in a distribution system is
fire protection
TCEQ rules require that water systems maintain what psi during normal operating conditions and not less than what psi during emergencies
35 psi normal
20 psi emergency
palatable water means the water is
aesthetically pleasing
potable water means the water is
safe for human consumption
maintaining the minimum operating pressure in the distribution system helps to prevent
backflow contamination
the distribution system must provide what?
water at a continuous delivery of sufficent volumne of potalbe and palatable water at adequate pressure
the purpose of a water main is
to transport water throughout the system
water mains must be sized to meet the....
demand of peak flow, average flow, future growth and fire flow
design engineers estimate how many gallons/person/day?
130 gallons/person/day
the most common type of pipe joints in use today are:
push-on joints
mechnical joints
what weakens PVC pipe?
prolonged exposure to natural sunlight
what is a service line?
line used to transport water from the main line to the customers property line
what is the typical size for a single family service line?
3/4 to 1 in
the most common type of valve found on a customer service line is?
ball valve
it is recommended that all underground main line valves be operated at least?
once per year
if a system had two overhead storage tanks with different overflow elevations, the levels in the two tanks could be controlled with a?
altitude valve
on the discharge side of a centrifugal pump which pumps into the distribution systems, the operator would expect to find what kind of valve?
check valve
the primary purpose of a fire hydrant is
to provide water supply for fire fighting
a fire hydrant shall NOT be places on a main line smaller than?
TCEQ requires that all ground storage, elevated storange and pressure tanks be inspected?
one of the simplest and most commone electric motors found in teh distribution system is the
squirrel-cage induction motor
one psi will cause water to rise in a column of pipe
2.31 ft
the most common types of residential water meters found in distribution systems are
positive displacement and multi-jet
unaccounted for water should be less then what percent?
all new main lines installed shall be no less than what size?
2 in
fire hydrants shall be installed no closer than..... ft from sewer lines
9 ft
the term pathogen means
disease causing
the presence of fecal coliform or e. coli in a water sample indicates
intestinal waste in the sample
water born diseases:
if when collecting a water sample you discover there is little or no chlorine in the water at the sample site what do you do?
dont collect sample and immediately check chlorination equipment and begin flushing hte distribution system
a 300mg/L chlorine dosage wil require a contact time of how long?
15 mins
rotten-egg or sewer gas smell indicates what?
hydrogen sulfide gas
chemical analysis results must be kept how long?
10 yrs
x of y cards