Initiating devices are the first sensors in a fire alarm system that detect the presence of fire. The main initiating devices include smoke detectors, heat detectors, manually operated pull stations, and sprinkler water flow sensors. Smoke detectors come in ionization, photoelectric, and dual types. Heat detectors include fixed temperature and rate-of-rise types. Manually operated pull stations allow users to manually trigger the alarm. Sprinkler water flow sensors detect water flow from sprinklers and trigger the alarm. These initiating devices sense fire and initiate the fire alarm system.

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Initiating Devices in a Fire Alarm System
What are initiating Devices?
In an other article, we were introduced to the Fire Alarm System.
The system actually is a fulfilling compact loop in itself which actually
frees manual intervention & dependence to a substantial amount. It
works with the help of some smart devices. But here too, the first
input is the instance of Fire and then the rest of the system. So the
first set of devices is the Initiating Devices. They are the ones which
actually sense that there is a danger. Without them, you can’t predict
that there is a fire. Let’s understand what Initiating Devices are in a
little more depth:
Typical Initiating Devices are:
1. Smoke Detectors:
Smoke Detectors detect Smoke in the premise & initiate the further
system. There are 3 types used:-
(A)Ionization Type:
In this type of a smoke detector, you will find an
ionization chamber, which consists of very small
amount of Americium-241, which is a radioactive
Isotope.

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When smoke enters any premise, an electric current is created &
signals are passed to the further system.
(B) Photoelectric Type:
The Video above demonstrates how a
Photoelectric Smoke Detector works.
It mainly detects the difference in light
inside the room or premises. These are the
most widely used Smoke detectors. (Refer
this article)
Photo electric type smoke detector can detect the smoke by a couple
of infrared diodes. The principal of detecting is particle in the smoke
can reflect infrared lights. The chamber can shield external light, but
does not affect the smoke into it. While there is no smoke the diode
can receive very week infrared light. When the smoke enters in the
chamber diode can receive more and more light and the detector
can give out alarm single when the smoke reaches the certain
density.
(C) Dual Type:
These are the combo type where Ionization &
Photoelectric smoke detectors are smartly
used. It balances the usage to alert the system
smartly.
2. Heat Detectors:
Heat Detectors actually track if there is a
major Temperature Difference within the
premise. There are Fixed Temperature Heat
Detectors & Rate of Rise (ROR) Heat
Detectors.

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The Fixed Temperature Heat Detectors
actually changes its state from Solid to Liquid with the rise of
temperature. So this initiates
The Rate of Rise Heat Detectors, unlike the Fixed Temp
Detectors, works on the variation of temperature tracks. In a minute
if it observes rapid temperature difference from 6.7 to 8.3 degrees, it
will initiate the follow up system.
Details of these can be seen at
3. Manually operated pull stations:
A Manually operated pull station
device, usually wall-mounted, by pulling
the handle down or up, initiates an alarm.
In its simplest form, the user activates the
alarm by pulling the handle down, which
completes a circuit and locks the handle in
the activated position.
Are they still in operation? Yes and No. Read
details
4. Sprinkler water flow sensors:
Sprinkler Shower Sensor is a device on which a
transparent
When the surrounding temperature in the room goes
beyond 58
Water in the pipeline starts sprinkling in the room.
This gives an indication to the Control Panel through
the Flow Switch to actuate the Fire Alarm System.
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Fixed Temperature Heat Detectors contain Eutectic Alloy, which
actually changes its state from Solid to Liquid with the rise of
initiates a following system.
The Rate of Rise Heat Detectors, unlike the Fixed Temperature Heat
on the variation of temperature tracks. In a minute
if it observes rapid temperature difference from 6.7 to 8.3 degrees, it
the follow up system.
Details of these can be seen at this article in Wikipedia.
. Manually operated pull stations:
Manually operated pull station is a
mounted, by pulling
the handle down or up, initiates an alarm.
st form, the user activates the
alarm by pulling the handle down, which
completes a circuit and locks the handle in
the activated position.
Are they still in operation? Yes and No. Read this article for more
. Sprinkler water flow sensors:
Sprinkler Shower Sensor is a device on which a
transparent bulb containing Red Alcohol is mounted.
When the surrounding temperature in the room goes
beyond 580
c; the Bulb bursts. Immediately the
Water in the pipeline starts sprinkling in the room.
This gives an indication to the Control Panel through
the Flow Switch to actuate the Fire Alarm System.
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contain Eutectic Alloy, which
actually changes its state from Solid to Liquid with the rise of
erature Heat
on the variation of temperature tracks. In a minute
if it observes rapid temperature difference from 6.7 to 8.3 degrees, it
this article for more
Sprinkler Shower Sensor is a device on which a
bulb containing Red Alcohol is mounted.
When the surrounding temperature in the room goes
Immediately the
Water in the pipeline starts sprinkling in the room.
This gives an indication to the Control Panel through
the Flow Switch to actuate the Fire Alarm System.

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These are some of the major Initiating Devices used in a Fire Alarm
System. Many companies, manufacturers and system providers come
up with their own smart designs.
At Vighnaharta, we strongly believe in offering a very flexible, yet
technically appropriate solution to our clients. Please contact us so
that our team will find out what will be the best solution for you.
Realty Automation & Security Systems Pvt. Ltd.
Website: www.vighnaharta.in
Email Id: sales@vighnaharta.in
Contact Us: +91 9011033259