Today we will see how to make project on 'project on fire alarm for class 12th' this project is only for class 12th student and this project is belongs to 'chemistry' in this project we will cover following steps
1. CERTIFICATE OF
EXCELLENCE
2. ACKNOWLEDGEMENT
3. AIM OF PROJECT
4. INTRODUCTION
5. THEORY
6. APPARATUS REQUIRED
7. WORKING
8. OBSERVATION
9. CONCLUSION
10.PRECAUTIONS
11. BIBLIOGRAPHY
INTRODUCTION
An automatic fire
alarm system is designed to detect the unwanted presence of fire by
monitoring environmental changes associated with combustion. In general, a fire
alarm system is either classified as automatic, manually activated, or both.
Automatic fire alarm systems can be used to notify people to evacuate in the
event of a fire or other emergency, to summon emergency services, and to
prepare the structure and associated systems to control the spread of fire and
smoke. Fire alarm systems have become increasingly sophisticated and
functionally more capable and reliable in recent years. They are designed to
fulfill two general requirements: protection of property and assets and
protection of life. As a result of state and local codes, the life-safety
aspect of fire protection has become a major factor in the last two decades.
There are a number of reasons for the substantial increases in the life-safety
form of fire protection during recent years, foremost of which are
1.
The proliferation of high-rise construction and
the concern for life safety within these buildings.
2.
A growing awareness of the life-safety hazard in
residential, institutional, and educational occupancies.
3.
Increased hazards caused by new building
materials and furnishings that create large amounts of toxic combustion
products (i.e., plastics, synthetic fabrics, etc.).
4. Vast improvements
in smoke detection and related technology made possible through quantum advances
in electronic technology.
5. The passing of
the Americans with Disabilities Act (ADA), signed into law on July 26, 1990, providing
comprehensive civil rights protection for individuals with disabilities. With
an effective date of January 26, 1992, these requirements included detailed
accessibility standards for both new construction and Renovation towards the
goal of equal usability of buildings for everyone, regardless of limitations of
sight, hearing, and mobility. This had a significant impact on fire alarm
system signaling devices, power requirements, and device locations.
THEORY
A fire alarm system has a number of devices
working together to detect and warn people through visual and audio appliances
when smoke, fire,
carbon
monoxide or other emergencies are present. These alarms may be activated
automatically from smoke detectors and heat detectors or may also be activated
via manual fire alarm activation devices such as manual call points or pull
stations. Alarms can be either motorized bells or wall mountable sounders or
horns. They can also be speaker strobes which sound an alarm, followed by a
voice evacuation message which warns people inside the building not to use the
elevators. Fire alarm sounders can be set to certain frequencies and different
tones including low, medium and high, depending on the country and manufacturer
of the device.
WE WILL BE
STUDYING A THERMISTOR BASED FIRE ALARM WHERE WE WILL USE FIRE SWITCH TO CONTROL
THE CIRCUIT.
COMPONENTS OF
2. PCB
Board
3.
Fire switch
5.
Resistance 01K
6. PNP
Transistor 369
8.
Capacitor 0.04μF
9.
Buzzer
10.
Connecting wires
CIRCUIT WORKING
All the components are soldered using
soldering wire and are fixed on PCB board. Resistors of 330k and 0.1k are used
to bias transistors so that they work according to our requirement in the
circuit and control the flow of current I the desired way. We have npn and pnp
transistors to control the flow of current. Capacitors store the energy and let
the alarm sound for some time after the fire switch turns off. We have a buzzer
that will sound as soon as a fire is detected by the fire switch. The main
component of the whole circuit is the fire switch that is responsible for its
working.
FIRE SWITCH
It’s a device that works on the stimulus of
temperature. It consists of a bimetallic strips that are initially separated
when there is no fire that is the temperature is normal room temperature. As
soon as there is a fire the temperature goes up and the strips comes closer to
touch each other and complete the circuit. This lead the current to flow in the
circuit and the buzzer sounds.
Observations
We have seen that initially there was no
buzzer sound as none of the fire was detected.
When we bring a match stick near the fire
switch with a time lag of 5-10 seconds the buzzer starts giving sound as the
fire is detected and the circuit is completed by the action of bimetallic
strip.
When we remove the burning match stick away
from switch, the buzzer continues to give the sound for some time due to action
of capacitor and time is required by switch to return to room temperature.
Conclusion
A fire alarm is a device that
detects the presence of fire and atmospheric changes relating to smoke. In some
cases, a firm alarm is a part of a complete security system, in addition to a
burglary protection system. The fire alarm operates to alert people to evacuate
a location in which a fire or smoke accumulation is present. When functioning
properly, a fire alarm will sound to notify people of an immediate fire
emergency. Fire alarms can be found in homes, schools, churches and businesses,
and function as the catalyst to saving lives. For most fire alarms, when
sounded, a beep, bell or horn noise is made. This distinct sound exists to
allow the notification to be heard. The fire alarm constructed by this project
work is reliable at low cost.
Precautions
1.
Components
of the circuit should be handled carefully.
2.
Care
should be taken while soldering as it may burn the skin.
3. Connecting wires should be insulated to
prevent disturbance.
4. Connections should be tight as it
may break easily.
5. Soldering must be done carefully as
it may burn the PCB board.
BIBLIOGRAPHY
1) NCERT textbook class 12
2) NCERT physics lab Manuel
3) INTERNET
4) www.yahoo.com
5) www.google.com
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