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BUILDING SERVICES 2
QSB 2714
BACHELOR OF QUANTITY SURVEYING (HONOURS)
SEMESTER 3
TESCO EXTRA (MUTIARA DAMANSARA)
Abang Azrin Bin Abang Affandi
0319073
Chua Jia Cheng
0315160
Goh Jeng Jhieh
0315080
Jake Sia Chyi Sern
0314396
Kellyann Hiew Yau Mei
0319532
Muhammad Aiman Bin Zainul Abidin
0321832
Rachel Emma Betty Ernesta 0317966
1
ABSTRACT
The case study of this report is on Tesco Extra which is located in Mutiara Damansara. The
four building services (mechanical and air-conditioning system, fire protection system,
vertical transportation and electrical supply) is analysed and information on the systems are
given. Recommendation is provided for the fire protection and vertical transportation to
improve the services.
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ABBREVIATIONS
% Percent
AC Alternating Current
AHU Air Handling Unit
CO₂ Carbon Dioxide
COPHK Hong Kong's Code of Practice for minimum Fire Service Installations and Equipment and Inspection, Testing and Maintenance of Installations and Equipment
This type of installation is most frequently used as it allows customers to travel quickly to
the upper floors without any waiting time.
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Application of Vertical Transportation at Tesco Extra
Photograph 12: Floor Plan of Tesco Extra
In the case of Tesco Extra, the building only has two and a half floors whereby the half
floor, being named Mezzanine floor, only has 4 shops compared to the vast amount of
retails provided in the ground and first floor. For a renowned hypermarket store like Tesco
Extra, it is extremely vital for the design team to plan, arrange and provide efficient vertical
transport to the building.
Photograph 13: Travellator at Tesco Extra
To travel from the ground to first floor, the building acquires the use of an inclined moving
walkway. A moving walkway is also known as a travellator. It is very similar to a normal
escalator. The main difference of an escalator to a moving walkway is that it provides a flat
platform throughout the whole transportation system in comparison to the steps provided by
escalators. This system provides the same function as an escalator, which is to transport
people across an inclined plane over a short to medium distance by using a conveyor
mechanism. This system suits the requirement for Tesco Extra, as customers of the
hypermarket are bound to be pushing their trollies full of groceries to their respective cars.
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The provision of these moving walkways could help the customers save energy by reducing
the amount of effort in pushing the trollies from a fair amount of distance considering the
load bearing of the trollies. These moving walkway machines are provided at both ends of
the rectangular shaped building, which is very much as efficient as it can get.
Photograph 14: Escalator at Tesco Extra
To get to the Mezzanine floor, a normal sized two-way traffic escalator flight is installed for
the use of the customers of Tesco Extra. A moving walkway is not required around this area
as trollies are prohibited within the Mezzanine floor area. The arrangement of both the
escalator and travellator in Tesco Extra use two-way traffic system. During the course of
emergencies or a case of a very heavy pedestrian traffic, both the escalator and the
travellator directions could be adjusted to suit the traffic flow. This gives precision to
travelling within the building.
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Elevators
Photograph 15: Elevator in Tesco Extra
Photograph 16: Service Elevator
An elevator is a platform, either open or enclosed, which is used for lifting of people or
freight to upper floors within a building. Elevators are a standard part of any tall commercial
or residential building. Factors that affect the number of lifts in a building are: -
1. Population of the building
2. Type of building occupancy
3. The starting and finishing times of the population, whether staggered or unified.
4. Number of floors and heights.
5. Position of building in relation to public transport services.
General specification of a lift car should be able to carry 21 ~ 24 passengers, lift entrances
are about 1100 ~ 1200mm wide with 2 pieces of doors, door closing time should take 3.1
seconds for 1100mm width door and 3.4 seconds for 1200mm doors, transfer time of
passengers are about 1.6 ~ 2.0 seconds in and out, and the acceleration of lift car is
1.0m/sec2.
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Type of lift Car speed (m/s)
Passengers, up to 4 floors 0.3 ~ 0.8
4 ~ 9 floors 0.8 ~ 2.0
9 ~ 15 floors 2.0 ~ 5.0
Over 15 floors 5.0 ~ 7.0
Paternoster Up to 0.4
Goods, to any height 0.2 ~ 1.0
Hydraulic, passengers or goods, max 4 or 5 floors 0.1 ~ 1.0
Table 2: General specification for car speed of a lift
A round trip time is basically the time in seconds taken by a single lift to travel from ground
floor to the top floor, including the probable number of stops, and return to the ground floor.
The flow rate percentage (%) of the total population requiring lift service during a 5 minute
peak demand period is 10 % to 25 %. If flow rate is not given for staggered starting time, it
is assumed to be 12 % and if flow rate is not given for unified starting time, it is assumed to
be 17 %.
There are 2 main types of elevator available in Tesco Extra, which are hydraulic and
electric elevators. Electric elevator is a type of vertical transport equipment that efficiently
moves people or goods between floors of a building. It is powered by electric motors that
either drives traction cables or counterweight systems. Hydraulic elevators are elevators
which are powered by a piston that travels inside a cylinder. An electric motor pumps oil
into the cylinder to move the piston. The piston smoothly lifts the elevator cab. Electrical
valves control the release of the oil for a gentle descent.
1. Control System – Located in a machine room above the elevator shaft.
2. Electric Motor – Motor rotates and the sheave will either raise or lower the elevator.
3. Sheave – A pulley with grooves around the circumference. The sheave grips the hoist ropes, and it moves as the sheave is rotating.
4. Counter weight – Weighs about the same as the car filled to 40-percent capacity, mainly to balance the speed of elevator when it goes too fast.
5. Guide rails – Along the sides of the elevator shaft, to prevent the car from swaying back and forth, also work with the safety system to stop the car in emergency.
Figure 11: Electric Elevator
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In Tesco, there are 2 different types of elevators to serve different purposes. The first one is
an electric type which is to carry customers or workers to different levels in the building and
another one is the freight elevator which is to transport trolleys from basement floor to
levels above for shopping purpose. Electric elevator is only provided at 1 side of the
building while the escalator is provided at another side of the building. The arrangement of
escalator and elevator is considered good to provide vertical transport at both different
entrances. But the problem comes in during peak hour, as a lot of people have to wait at
the elevator for a long time since only 1 elevator is provided and the car lift is small and is
unable to carry a lot of people at once. It also cannot be easily found as the elevator is
placed behind a wall.
1. Tank - Shall have sufficient capacity to provide an adequate reserve to prevent the entrance of air or other gas into the system.
2. Motor - Used in hydraulic elevator is constantly pushing Liquid into the cylinder to lift the elevator.
3. Valve - Let liquid out of system, keep the pressure low when open & increase pressure when closed.
4. Actuator - The device that transfers fluid or electrical energy into mechanical energy.
Figure 12: Hydraulic System
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Electrical Supply
Electrical System
Figure 13: Electrical Distribution Grid
Figure 13 shows the design for electrical distribution for a city or a town. Electricity is
generated from the generating station or power plant (Brain & Roos, 2015). There are a few
types of generating stations some of which are thermal power plant, hydropower plant and
nuclear power plant. The power travels through a distribution grid that works by dividing the
electrical power into networks which then supplies electrical power to every building in the
vicinity.
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Transformers
Figure 14: Transformer
The transformer is an apparatus used to convert the system’s voltage to increase the
efficiency of distribution for each respective area as per Figure 14. Substations may include
transformers that reduce the voltage of two different transmission voltages. Electrical
transformers can be configured as either a single-phase or a three-phase configuration.
There are several necessary specifications to specify when it comes to electrical
transformers. These include: maximum secondary voltage rating, maximum secondary
current rating, maximum power rating, and output type. An electrical transformer may give
more than one secondary voltage value. Output choices include AC or DC.
Figure 15: Step-Up Transformer
Figure 16: Step-Down Transformer
The transformers can perform both step-up and step-down depending on how it is built. The
transformer increases the voltage from high to low of the electricity being supplied by
increasing the number of coils and decreases the voltage by reducing the number of coils
as per Figure 15 and Figure 16 respectively (Electrical4U, 2015).
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Service Entrance
Figure 17: Service Entrance
The service entrance is the point where electricity enters the building, which in this case
would be Tesco Extra. It is the directly linked to the TNB substation and is located in Tesco
Extra. A grounding system is used that acts like a drain for current to flow into the building.
The grounding system consist of two parts which are the equipment grounding conductors
and earth grounding conductors used for ground fault protection and dissipating induced
voltages and surges respectively. Although TNB substation is located in the premises of
Tesco, no personnel can simply enter without the permission of TNB.
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Main Switchboard
Photograph 17: Main Switchboard 1
Photograph 18: Main Switchboard 2
Photograph 19: Main Switchboard Room
The main switchboard (MSB), as shown in
Photograph 17 and
Photograph 18, is an important part of any electrical installation and is generally where the
service protection device and supply authority metering equipment is located. The main
switchboard is located inside Tesco Extra at the point which incoming power supply
distributes throughout the building (Schneider Electric, 2015). It distributes the large
incoming power supply into a smaller form that can be easily controlled. Protection is also
provided; tripping the breakers for when current overloads or short circuits.
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Distribution Panel
Figure 18: Example of Distribution Panel
Photograph 20: Distribution Panel in Tesco
The diagram above shows one of the many distribution panels in Tesco. It is usually
positioned in strategic locations all around Tesco and fixed to the wall. It is used to
distribute power to consuming appliances while providing a fuse or circuit breaker for each
circuit. The distribution panel normally comes with a metre for when the power oversupplies
and actives the circuit breaker to trip. Circuit breakers are automatic protection devices in
the distribution panel that turns off a circuit when they detect an overload. Circuit breakers
are similar in size to fuses, but gives better protection. When they trip, you can simply reset
the switch whereas fuses need to be replaced when there is an overload.
Requirements of Electrical Installation
There are some factors to be considered before installing the electrical system in a building
and Tesco has satisfied all of the some of which are enough capacity for purpose, minimum
wastage of current, prevention of fire, isolated and corresponding with laws and regulations.
As stated in the Uniform Building By Law 2012 Amendments on EE Bylaw 38A and
MS1525, 7.5, power factor correction capacitors should be the low loss type with losses per
kVAR not exceeding 0.35 W at upper temperature limit excluding the losses in the
discharge resistors. This is to reduce the energy lost in the capacitors and cables. It is also
written in 7.6, that to facilitate monitoring of energy consumption and energy management,
electrical energy meters should be installed at strategic load centre to identify consumption
by functional use (air conditioning, lighting, etc) (Izdihar, 2013). This is to effectively record
and control the usage of the electrical energy.
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PART 3 – RECOMMENDATION AND SOLUTION
Fire Protection System
There are various fire protection services installed in the vicinity of Tesco Extra such as the
two types of fire extinguisher, fire escape, hose reel, alarm bell, smoke detector and
sprinklers. Despite having sufficient fire protection, the building can be further improved to
withstand the disaster of a fire. Compartmentalisation should be included to help prevent
the spread of fire.
Even though Tesco Extra has taken the measures to provide plenty of sprinklers in the
building, there are times when a sprinkler can fail to douse the fire. The top five reasons
that sprinkler systems failed to operate or were ineffective during a fire were (Long, et al.,
2010):
1. System shut off (38%)
2. Inappropriate system for the type of fire (18%)
3. Water discharged did not reach fire (12%)
4. Lack of maintenance (12%)
5. Problem with water supply or not enough water discharged (9%)
Photograph 21: Food Court
Photograph 22: Bakery
As you can see from Photograph 21 as well as Photograph 22, Tesco Extra has a kitchen
that cooks and bakes freshly made food. If a fire were to ever occur in the kitchen and the
sprinklers were ineffective, the initial fire may erupt into a large scale fire and spread to
different areas and floors. Fire Compartmentation is designed to contain the fire to within
the area of starting point of the fire (A L Fire Systems, 2014). Compartmentation can help in
delaying the spread of fire before the fire brigade arrives to the location.
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According to COPHK Part 4.14, low rise commercial buildings are required to install
‘Automatic Actuating Devices’ (Fire Services Hong Kong, 2012). Fire shutters can be
installed in the premise to help satisfy the requirement. Modernised fire shutter can now
close at a controlled speed (typically 10 centimetres per second). With a combination of a
Fire Detection Interface (FDI) panel it is now possible for a fire roller shutter to initially
deploy to a pre-determined safe height, (normally just above head height) to act as a smoke
barrier while allowing people to escape (HVP Security Shutters , 2015).
The fire shutter is fully closed after a pre-determined time (following fire protocol for the
building) to create a fire resistant barrier. The FDI panel can also act as a visual and
acoustic alarm, alerting occupants that the fire shutter is about to close (HVP Security
Shutters , 2015)
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Vertical Transportation
Escalator/Travellator
A simple recommendation to the vertical transport of the building would be to adjust the
direction of the two-way traffic to only one-way traffic on each end of the building. Instead of
having a travellator moving in different directions at both ends, Tesco Extra could adjust the
travellator on one end going up and the other travellator on the other end of the building to
go down. This could help enhance the number of customers going all the way round the
building. This change to the arrangement of the moving walkway could also inevitably
increase the customer density and thus help boost sales among the retails available inside
the building area.
Elevator
Instead of having an elevator, we propose to have another escalator to replace the area
that the elevator was serving. Escalator can carry more people and save time compared to
waiting for the lift car from other levels to reach. At the same time, it is more spacious to
carry goods bought by customers, especially during peak hour.
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PART 4 – CONCLUSION
In conclusion, Tesco Extra has fulfilled the requirements of the required building services.
The building is operating a centralized air-conditioning system with a multi zone variable air
volume. This will allow the retail shops within Tesco Extra to adjust the temperature to their
own satisfaction. According to the first floor plan, they have over 40 Dry Powder fire
extinguishers, 5 CO₂ fire extinguishers, 9 hose reel, 9 alarm bells and 9 breakglass. Their
premise is installed with an automatic CO₂ at selected areas and a sufficient amount of
smoke detector and sprinklers. Despite that, the fire protection services can be further
improved with the implementation of fire shutters which would compartmentalise the area.
Instead of escalators, Tesco Extra has a travellator to accommodate the use of trolleys and
service elevators to transport the trolleys back into the storage for customers to use. It is
recommended for the travellator to change from a two-way direction to a one-way direction.
This will allows customers to venture and notice the retail stores along the sides of Tesco
Extra.
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Fire Services Hong Kong, 2012. Code of Practice for minimum Fire Service Installations
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