cold waterr Flashcards
What is water
Water is a compound consisting of two atoms of hydrogen and one atom of
oxygen
What is evaporation
water is
constantly evaporating from the
oceans, lakes, rivers and streams
into the air
what is transpiration
water moves through plants until it reaches the leaves where it evaporates into the atmosphere
what is a precipitation
– another word for rain. When water vapour precipitates, it condenses back into
water droplets and falls to the earth as rain, hail and snow.
what are the different types of water
sea water
ice
ground and surface water
what are shallow wells
Historically, shallow wells have been
dug by hand and only penetrate the
first water-bearing strata or aquifer.
They should be considered as
dangerous because of the close
proximity to leaking drains.
what is aquifers
Aquifers are naturally occurring rock and sand formations that have the ability to hold vast quantities of
usually clean water deep below the Earth’s surface.
what are Artesian wells and springs
The water from Artesian springs rise
from under the ground under its own
pressure in situations where the
spring opening is below the level of
the water table. The water is usually
very good quality as the water is filtered naturally through the rock due to its constant movement.
what are bore holes
what is screening
First, the water is passed through a series of coarse meshes to remove large debris such as leaves, plant
material and other fragments
Flocculation
Here, a chemical coagulant is added to the water to act as a
binding agent to remove colour, turbidity and algae. This
process also allows any dissolved metals such as aluminium
and iron to precipitate. This leads to the formation of a ‘floc’
which can then be removed by other processes.
what is sedimentation
Sedimentation is designed to slow down the velocity of the water to allow any solid matter, such as grit, mud
and decaying vegetation missed by the screening process, to sink under gravity to the bottom of the
sedimentation tanks.
what are the types of filtration
slow sand filters
pressure filters
what is disinfection
The final stage of the water treatment process is disinfection. This is where a small amount of chlorine,
usually less than 1 milligram per litre of water, is added to kill off any bacteria that may have escaped all the
other processes. This is usually injected into the water just before it enters the water supply.
what is distribution of water supply
After the water has gone through the treatment process, it is distributed to homes and businesses
throughout the UK by one of two ways:
By gravity distribution
By pumped distribution
what is gravity distribution
Gravity water distribution
begins when the reservoir is
sited on high ground. The
water, once it has gone
through the treatment
process, is fed to the
distribution network by
gravity. No pumping is
necessary as the head of
water created by the
vertical distance between the reservoir and the outlets is sufficient to create the pressure required at the
taps and outlets in homes, offices and factories.
what is pumped distribution
After going through the
water treatment process,
the water is pumped to a
service reservoir held on a
tower. From here, the
water distributes to the
water network via gravity.
what is Distribution of water to cities, towns and villages
Water is supplied to cities, towns and villages via a grid network of pipes. These are known as trunk mains
and will vary in diameter depending on the population, the purpose of the cold water main or the likely
demand for water in a particular area.
what is the communication pipe
The communication pipe is
installed by and remains the
property of the water undertaker.
It connects to the water main via
a ferrule and terminates at the
property boundary.
what is the supply pipe
The supply pipe runs from the boundary of the property to the building, terminating inside the building with
a screw down stop tap manufactured to BS1010.
advantage of cold water
It is the most cost effective cold water system
installation
disadvantage of cold water
The water pressure may drop at times of peak demand
what is an advantage
Mains cold water is available at all cold water taps and outlets
what is a disadvantage
There is no cold water storage if the cold water main is under repair
what is an advantage
Little or no structural support is required for cisterns in the roof space
what is a disadvantage
Greater wear on taps and valves, which can increase the noise within the system
what is an advantage
Good pressure at ALL cold water outlets
what is a disadvantage
Greater condensation build-up on pipework that is often mistaken for a leak
what is direct system
Generally speaking, most direct systems utilise a 15mm rising main with
15mm pipework to all cold water outlets. This is sufficient for small
installations where a combination boiler supplying hot water is installed,
without en-suite bathrooms and shower rooms.
what is indirect systems
The indirect system of cold water supply is designed for areas where the
cold water supply pressure is low and not capable for supplying the full
water requirements of the system design.
What is the primary purpose of flocculation in water treatment?
To remove colour and turbidity
What is the typical size of a rising main for most dwellings?
15mm
What is the primary purpose of a drain valve in plumbing systems?
to allow complete system drainage
Which type of pump boosts water after the shower valve?
single impeller
What is required for cold water cisterns installed in the roof space?
structural support
Which valve ensures full bore water flow in low-pressure systems?
gate valve
What does activated carbon in filters primarily remove?
chlorine and odors
How should MDPE pipes enter a building to prevent UV degradation?
with no more than 150mm showing
Which ion is used in base exchange water softeners to replace hardness?
sodium
What supplies an instantaneous electric shower?
cold water mains and internal heater
What is a unique feature of thermostatic mixing valves?
self adjusting to maintain water temperature
Who is responsible for monitoring private water supplies?
local authorities
What material is resistant to de-zincification in fittings?
gunmetal
What level of chlorine is typically added during disinfection?
less than 1 mg/L
