| Building Services |
| Designing the Electrical Backbone System for
an Intelligent Building |
| By Michael M. F. Waye, Hong Kongmfw.hk@pbasia.com
852-2579-8672, mfw.hk@pbasia.com |
| The Kowloon Canton Railway Corporation (KCRC) uses
up-to-date technology to keep its expansive organization highly efficient.
PB has designed a wiring system that will support KCRC headquarter·s
requirements now and well into the future. |
|
The Kowloon Canton Railway Corporation (KCRC), a major corporation
with diversified operations, has experienced several years of expansion
and modifications of the several railway systems it operates and maintains.
To ensure smooth running of its organization, KCRC decided to build
a new headquarters building and consolidate all of its staff into
one location. KCRC wanted the headquarters building to be designed
as an intelligent building, one that will be capable of handling its
telecommunication needs for voice, data and other signals well into
the future. PB, the mechanical and electrical consultant for the entire
building, was given the additional duty of implementing the backbone
system to support the building’s electronic, computer and communication
systems.
Critical Requirements for Design
Some of the client’s critical requirements for the building
were that:
- The building be provisioned with top quality
HVAC, electrical, fire, plumbing and drainage systems.
- There be an integrated cabling system so
that both office computer communication and building electronics
could be interfaced easily and managed efficiently.
- The implemented system allow for easy relocation
of offices (such changes can occur on an almost daily basis).
We decided to provide a backbone (structured) wiring system, which
will be the common cabling system for all voice and data communication
systems and can be integrated with the building electronic systems.
Data and Voice. We examined the data and voice communication
systems for the building predominantly on a floor-by-floor basis and
for KCRC’s total breadth of operations. The solution we designed
is comprised of:
- A data communication system for a local
area network for each floor of the building
- A central database system for sharing of
information
- A data communication system for a metropolitan
area network that extends to the stations of the railway
- A private automatic branch exchange (PABX)
system for internal and external telephone communication
- A voice communication system that includes
background music and emergency broadcast capabilities.
This solution can provide communication at the physical layer level
of open system interconnection (OSI). A more advanced level of interconnection
(such as network level) can be built on it.
Building Electronics. Various electronic systems
that were to be part of our wiring system included:
- A security system with intrusion alarm and
access control
- A building automation system for controlling
and monitoring the HVAC system
- A video communication system with closed
circuit television.
The structured wiring system complies with the electromagnetic compatibility
(EMC) requirements for compatibility between various systems.
Overall Configuration
Components. We decided that a mixture of single mode
optical fiber cable and unshielded twisted pair (UTP) copper cable
would be used for the structured wiring system because it is the most
cost-effective means to fulfill the client’s needs. Optical
fiber cable could be applied for high baud rate communication. Copper
UTP cables could provide direct and easy connection for low bandwidth
and low baud rate communications, such as the telephone and public
address systems. A separate coaxial cable system was the most cost-effective
system for video communication.
Topology. Star topology was used in the structured
wiring system. The main distribution frame was located at the central
equipment room where the PABX was located. Jack panels were provided
at both the main distribution frame and intermediate distribution
frames on each floor. To ensure that the LAN connections were viable,
in particular the Ethernet, the location of each intermediate distribution
frame was checked to see that none exceeded the limits imposed by
common office networking topology. Light distribution frames were
provided on each floor with space reserved for optical equipment.
Because the optical fiber cables may be used for backup of copper
cable, the light distribution frames were located close to the copper
intermediate distribution frame.
Sizing. A saturated approach was used to size the
communication system in order to facilitate the flexibility needed
for moving offices. The complete system was provisioned according
to the usage of each floor. The usable area of the floor was calculated
and the maximum quantity of work stations was estimated. One voice,
two data, and one spare communication line were allowed for each work
station.
To size the electronic systems, we first established the requirements
for each system, then calculated the total requirement for the entire
horizontal wiring system. Typically, we used:
- Four pair of Category 5 UTP cable for the horizontal wiring
to each work station
- Three-hundred pair of Category 3 UTP cable
for the vertical cable risers
- A minimum of two 300-pair cables for each
floor to provide redundancy
- Twelve-core single-mode optical fiber cable
for the vertical riser
- One 12-core fiber cable assigned to each
floor.
System Meets Client’s Needs
Our design met the client’s critical requirements for flexibility
and easy and efficient handling. With the structured wiring system
in place, the building operator will be able to allow people to move
from floor to floor without any additional wiring or rewiring, and
be able to modify the electronic systems easily. The wiring space
of the building can be managed more effectively and efficiently, so
implementation of new technologies in the building, which require
some wiring connections, will be much easier.
Because the integrated wiring system will permit the implementation
of new telecommunication and computer technologies, the new building
is more than a three dimensional space. It has an added technology
dimension that will enable KCRC to implement any state-of-the-art
technology. |
|
| Note: A schematic diagram of the backbone system
is available from the author upon request. |
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