the measurement that is generally used to calculate the amount of water per day that is evaporated, formed into clouds and which falls as rain on the earth is
ccubic kilometres
the most popular disinfection method used for water is
chlorination
in a mild climate areas of BC, the required minimum depth of cover placed over the top of a water service is
.6m or 2'
backfill placed next to and over the top of a water service must not contain
stones boulders, cynders, or frozon earth
k and L hard copper tube can be used
above ground in a water distribution system
For copper tubing installed underground, joints shall be made by using..
brazing alloy
Every water service pipe shall be provided with a shut off valve
where the pipe enters the building
the minimum water service pipe is
3/4"
if the static line pressure exceeds 85 psi, what must be installed
a pressure reducing valve
to decrease the pressure supplied by a PRV, turn the regulating screw
counter clockwise
what meter is used on residential installations
positive displacement meter
in a rotating disk meter, the amount of water used is transmitted to the dial of the meter by a..
gear train
CIB meters are installed in areas of the province which have
freezing conditions only
Split case meters are made from
brass
what valve closes the turbine side during low flow in a compound meter?
compound
in an ARB system, the water usage data is captured in..
a solid state memory
what causes back siphonage?
nagative pressure or a reduced pressure in a supply pipe
If a customer fails to cooperation in the installation, maintenance, testing or inspection of a back flow prevention device, the authority can
terminate the water service or require an approved device at the property line
a minus pressure in a waterline will cause
back siphonage
Any water source or system other than the public water supply that may be available in a building or premise should be considered
an unsafe water supply
fire fighting pumps on ships are capable of boosting pressures to
200 psi
High velocity in a potable waterline could create a partial vacuum along its inside walls. true or false?
true
the backflow preventer used with a flushometer is a
atmospheric vacuum breaker
Back low preventers should b tested how often?
annually
the zone of reduced pressure in a reduced pressure backflow device must be able to maintain______ between the zone and the supply pressure
14 kpa or 2 psi
what backflow preventer is required for a drinking fountain
an air gap
what is the minimum distance of an air gap at a tank or sump
1" or 2 times the diameater of the inlet pipe
what is the type of device best suited for protection against back pressure
reduced pressure backflow device (RPBD)
Backflow into a drinking water line from a direct fpressure connection to a food processing line containing edible syrup under pressure from a circulating pump may be prevented by the installation of..
a double check valve assembly (DCVA)
Premise isolation is used mainly in
plants
wher an extreme health hazard is present and a mechanical backflow preventer is not adequate protection, an____ should also be used.
air gap
modern hot water tanks are designed for working pressures of up to
150 psi
what promots convection currents in an electrically heated hot water tank
lower emersion heater
what tank has the slowest recovery rate
electrically heated tank
the releif valve discharge piping drains by
gravity
A pressure heat rupture would not be caused by corrosion factors and heat weakewning. true or false
false
the temperature of superheated water in a domestic hot water tank is above..
212 degrees farenheigt
the standard T &P valve temperature reief setting is
99 deg celcius or 212 deg farenheight
a domestic hot water ciruculation pump is required
on long runs of hot water piping
you should use ___ valves to balance multiple return lines in a domestic hot water circulation system
BALL valve
there will be a _____ on the outer cover of a hot water storage tank which has a pin hole in the tank wall
hot spot
What is used to replace plugged galvanized nipples on hot water storage tanks
plastic lined nipples
The inside of old water copper lines can be dissolved by
carbon dioxide
the only effective solution to scale build up in a domestic hot water tankk is to
have the water treated before heating
What is used to check a fuse that visually appears to be okay
a continuity tester
before replaceing an immersion heater element, the power is first --------- and the tank is ________ to a point below the element.
disconnected; drained
the majority of new tanks came equipped with a ___ immersion heater element
