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Design And Construction Of Fire Alarm System In A Two Storey Building
CHAPTER ONE -- [Total Page(s) 4]
Page 3 of 4
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CABLE
A
cable is of long insulated single conductor solid or stranded) or of
two or more such conductors, each provided with its own insulation,
which are laid up together. Basic parts of cable are:
(a) The conductor
(b) Insulator
A.C. CONTACTORS
These
are mechanical devices whose function in any given system is for making
and breaking of circuits on receipt of electrical signals (current)
from the supply. They depend for their operation on the electromagnetic
principles.
However, it can also be defined as a device for
repeatedly establishing and interrupting an electric power circuit. It
can be seen from the meaning of contactor that it’s principle function
is to carry the current when the contacts are closed and to interrupt
the circuit by opening the contacts.
Contactors may be of various types
(a) Manually operated
(b) Electrically operated, that operated by air cylinder. They may be of various sizes and details of construction.
SOUNDERS
These
are devices in which electrical signals are converted into sound
signals, e.g. bells, boosters, sirens etc. The types and the locations
should be such that alarms are clearly audible to people using the
building. They must not have a similar sound to any other device on the
premises.
MANUAL (BREAK THE GLASS)
They are coloured red, and are
located so that no person has to travel more than 30m from any position
within the premises in order to raise the alarm. They are located on
exist routes and in particular on floor landings of staircases and exit
to streets. They should be fixed at a height of 1.4 above the floor at
easily accessible, well illuminated, conspicuous positions free from
obstruction.
CHAPTER ONE -- [Total Page(s) 4]
Page 3 of 4
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