Liam Tanti
Assignment 1 of 4. Hot and Cold-Water Services
ACN 4.2C
Task 1
Criteria 1.1 K&U
a. Direct system of a cold-water supply.
A direct cold-water supply system in a local domestic dwelling is when the main gives water
directly to the water heater and the cold-water taps. This means that in a direct cold-water
supply, a head tank is not used and the water of the taps, toilet and other types of
equipment with water needs are adjacent to the mains water pressure.
Indirect system of a cold-water supply.
An indirect cold-water supply system in a domestic dwelling is when cold water is provided
to the house at mains pressure, hence it goes directly into a head tank/ expansion tank, and
the cold water used in the house, such as taps, showers, and other sources, is being fed from
the head tank. This means that the cold water is not coming directly from the main but is
being stored in a head tank before use. The tap for the kitchen sink is the only source that
receives water directly from the main since the water that is most likely going to be used for
cooking or washing plates need to be at category 1.
Liam Tanti
Assignment 1 of 4. Hot and Cold-Water Services
ACN 4.2C
b. Health Hazard 1 – backflow
Backflow is when an unwanted flow of water or germs is moving in the opposite direction. If
for instance, you drop the showerhead in the toilet bowl, a backflow has occurred and the
contaminated water inside the toilet bowl has infected the potable water.
Preventive measure – the best way to prevent backflow is by leaving an air gap. If the
water in the sink and faucet has an air gap, backflow will not occur, and the contaminated
water will not affect the potable water. Non-return valves are also another preventive
measure for backflow.
c. Health Hazard 2 – Galvanic action.
Galvanic action is when dissimilar metals are placed in a wet or damp environment and
corrosion occurs. When certain metals such as lead, copper, and galvanized steel are in
electrical contact with other types of certain metals and are both submerged in an
electrolyte like water.
Preventive measure – Apart from using other types of materials and metals that do not
corrode, a sacrificial anode can be placed inside cisterns, hot-water vessels, tanks, and
pipelines. The anode corrodes in this case, which prevents corrosion on the fitting
Liam Tanti
Assignment 1 of 4. Hot and Cold-Water Services
ACN 4.2C
Task 2
Criteria K&U 1.4
a. Direct system of hot-water supply
A direct system of hot-water supply is made up of one circuit of water where the water
is heated and pushed out by cold water. The water is always being replaced with cold
water and never reused.
Indirect system of hot-water supply
An indirect circuit is divided into two circuits, which are completely different from each
other. The water of circuit 1 gets heated by fossil fuels, such as gas, coal, etc… After the
water is heated, the water heats the water of circuit 2. This happens because the coil of
circuit 1 is being passed through circuit 2, hence the water heats up the coil, and the coil
heats the water inside circuit 2. Circuit 1 is a closed circuit, which means that the water
is always being reused, and cannot be replaced or transferred to circuit 2.
b. Health hazard 1 - Pressure.
Pressure occurs by the steam of the water generated when heated by the boiler/ water
heater. When the water is heated, the water expands and generates steam. The
expansion of the water builds up pressure inside the tank, hence, the higher the
temperature the more pressure is generated.
Preventive measure – A pressure relief valve is recommended in order to avoid
excessive pressure built inside the tank. A pressure relief valve works by releasing
excessive pressure inside the tank. A tank usually holds up to 150 PSI, when the pressure
exceeds that limit, the pressure relief valve opens to release extra pressure and lower
Liam Tanti
Assignment 1 of 4. Hot and Cold-Water Services
ACN 4.2C
the temperature. The pressure could lead to an explosion; hence it is always best to
avoid taking risks when it comes to the health of yourself and others.
Health hazard 2 - Temperature.
Task 3
Criteria A&A1.2
a.
Material
Jointing process
Properties Application
Copper pipes
Compression/ Soldering
Transportation of
cold/hot water
Cast iron
Compression
Waste and vent
Steel pipes
Butt weld
Gas supply
b.
Material
Stands for
Jointing process
Properties
application
ABS
Acrylonitrite Butadiene
Styrene
Cement solvent
Sanitary/ storm
water drainage/vent
piping
PE
Polyethylene
Underground water
services
PB
polybutylene
Fusion weld/
threading/cement
solvent
Push-fit
delivers good
resistance to freezing
temperatures
Task 4
Criteria K&U 1.5
a.
Heating
mediums
Electric
Solar
Gas
Advantage
Advantage
Disadvantage
Disadvantage
Low upfront
cost
Environmentally
friendly
Self-contained
unit
Easy to install
Affected by
blackouts
Depends on the
climate
Slightly shorter
lifespan
Slow heating time
Low
maintenance
Fast heating
time
High installation
cost
High maintenance
cost
Liam Tanti
Assignment 1 of 4. Hot and Cold-Water Services
ACN 4.2C
b.
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An electric water heater is most suitable in a domestic dwelling, since it is the
cheapest to install, and the need for hot water does not need to be instant.
A gas water heater is most suitable in hotels and air BnBs since they need to
provide their customers with hot water when they need it. The gas water heater
is most suitable for this scenario because they are not affected by blackouts and
is the fastest to heat up water.
A solar water heater is most recommended for restaurants and factories since
they are in need of hot water more frequently, and they will save a lot of money
on electricity.
Task 5
Criteria S&E 1.3
Direct cold-water distribution systems
Advantages
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You will save a lot of pipework, especially in multi-story buildings.
You will have access to fresh drinking water from all taps.
No pumps are used to pump water to cisterns since it’s direct cold-water
distribution.
Less installation cost because of pipework and storage tanks.
Disadvantages



Lowering of pressure in peak periods.
If some sort of damage occurs to one of the pipes, all the water supply to the
building will be stopped.
The pipes need to be strong enough or they will leak due to high pressure.
Indirect cold-water distribution systems
Advantages

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Pipes don’t need to be as strong as direct since the water pressure is reduced and is
less likely to be damaged by the water hammer.
Less pressure and plumbing materials lead to less wear and tear on all water
networks.
Less maintenance since an indirect water system doesn’t require extra burners.
Even though only one tap is provided with potable water, it cannot be contaminated
by back siphonage.
Liam Tanti
Assignment 1 of 4. Hot and Cold-Water Services
ACN 4.2C
Disadvantages
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The pumps and tank need to be regularly maintained.
The water being carried to the tank, and from the tank to the appliances results in
additional cost and pipework
Weight is added to the roof of the house due to the storage tank being full of water.
Due to the storage tank being on the roof, this causes problems in lower floors to
have immediate pressure. Such as showers and flushing valves.
Potable water is only available in the kitchen sink.
Scenarios
Direct cold-water supply
A scenario where a direct cold-water distribution system might be appropriate is a domestic building
in the northern region where the main supply and pressure are good due to large high-level
reservoirs.
Indirect cold-water supply
A scenario where an indirect cold-water distribution system is appropriate is a restaurant where he
needs access to high water pressure for a specific period of time. Even though an indirect
distribution system does not come at main pressure, it is capable of giving continuous pressure at
periods of time, whereas a direct distribution system is not capable if the main supply is inefficient
and is only available at certain times and not 24/7.
Liam Tanti
Assignment 1 of 4. Hot and Cold-Water Services
ACN 4.2C
References
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https://www.researchgate.net/figure/Direct-system-of-cold-watersupply_fig1_237370352
https://dolantethole.wordpress.com/2012/10/04/direct-and-indirect-cold-watersystems-2/
https://www.practicaldiy.com/plumbing/water-supply/indirect-water-supply.php
https://gharpedia.com/blog/indirect-water-supply-system/