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Definition of Backflow
The unplanned reversal of flow of water or mixtures of water and contaminants into the water supply system. See back-siphonage and back-pressure.
Definition of Cross connection
Any actual or potential connection between a potable water supply and a source of contamination.
Definition of Non-return valve
A valve that permits flow in one direction but prevents a return flow and is part of a hot or cold water system.
Definition of Valve vented storage water heater
(Also known as an unvented storage water heater.) A storage water heater in which the required venting to the atmosphere is controlled by a valve.
Definition of Back-pressure
A backflow condition caused by the downstream pressure becoming greater than the supply pressure.
what are the requirements for the gap of an air gap
be the greater of 25 mm or twice the supply pipe diameter
what are the three cross connection hazards
low, medium and high
what is the pressure 1 meter of head in KPa
9.81 KPa
drainpipes are required for hot water cylinders of more than what capacity
45 ltr
a hot water cylinders control thermostat should be set know less than what temperature to prevent the growth of legionella bacteria
600c
what is the temperature at an outlet of any sanitary fixture at a institution for people with physical disabilities
45 0c
the temperature of an electric and gas storage water heater shall be controlled by a ?
Thermostat
what is the acceptable flow rate and temperature of a shower
0.1 at 420c
which two places can hot water cylinder vent pipe terminated
outside the building
over the water tank supplying the storage water heater
what are the installation requirements for a Double check valve
there are none
how much cold-water storage is required for buildings with the classification of community care
50 ltr
how far away can a pressure relief valve be located from a hot water cylinder
1 meter
the pressure of a working sanitary fixture / appliance shall be no less than how much KPa
30
the working pressure at a sanitary fixture shall not be more than how many meters of head
50
the open vent for a storage water heater shall have a minimum standing water level of ? above the highest outlet
30 meters
what is the clearance for above the highest outlet served by a Atmospheric vacuum breaker
150 mm
when it comes to water storage heaters what is the other name for a Free outlet system
push through
A RPZ (Reduced pressure zone devices.) the relief valve outlet should not be instilled less than what measurement above the surrounding surface
300 mm
what is the minimum capacity for a solar water heater per square meter of collector area
50 ltrs
where roof penetrations are greater than what measurement is additional framing required
200 mm