Design And Construction Of A Fire Alarm System Using Thermistor

ABSTRACT

This project is titled design and construction of an automatic fire alarm. Fire alarm is an electronics device that is stored in a building to detect the presence of fire accident. 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 classified as either automatically actuated, manually actuated, or both. Automatic fire alarm systems are intended to notify the building occupants to evacuate in the event of a fire or other emergency, report the event to an off-premises location in order to summon emergency services, and to prepare the structure and associated systems to control the spread of fire and smoke. This fire alarm system composes of 555 timer IC and thermistor – which works as a smoke sensor. The aim of this project is to design and construct a fire alarm for a building that will detect the presence of fire accident in a building.

TABLE OF CONTENTS

COVER PAGE

TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

CHAPTER ONE

1.0      INTRODUCTION

1.1      BACKGROUND OF THE PROJECT

• AIM OF THE PROJECT
• OBJECTIVE OF THE PROJECT
• PURPOSE OF THE PROJECT
• SIGNIFICANCE OF THE PROJECT
• PARTS OF FIRE ALARM
• APPLICATION OF THE PROJECT
• LIMITATION OF THE PROJECT
• PROJECT ORGANISATION

CHAPTER TWO

LITERATURE REVIEW

• HISTORICAL BACKGROUND OF THE PROJECT
• REVIEW OF SMOKE DETECTOR
• REVIEW OF TYPES OF FIRE ALARM SYSTEM
• REVIEW OF FIRE ALARM DESIGN
• REVIEW OF FIRE ALARM INITIATING DEVICES
• FIRE ALARM NOTIFICATION APPLIANCES
• PARTS OF FIRE ALARM

CHAPTER THREE

3.0     CONSTRUCTION METHODOLOGY

3.1      BLOCK DIAGRAM OF THE SYSTEM

3.2      CIRCUIT DIAGRAM

3.3      CIRCUIT OPERATION AND DESCRIPTION

3.4      POWER SUPPLY UNIT

3.5      PARTS LIST

3.6      DESCRIPTION OF MAJOR COMPONENTS USED

CHAPTER FOUR

4.0      TESTING AND RESULTS

• CONSTRUCTION PROCEDURE AND TESTING
• INSTALLATION OF THE COMPLET DESIGN
• ASSEMBLING OF SECTIONS
• TESTING OF SYSTEM OPERATION

CHAPTER FIVE

• CONCLUSION
• RECOMMENDATION
• REFERENCES

CHAPTER ONE

1.0                                                      INTRODUCTION

In modern society, it is impossible to imagine house or building without a fire accident detector. Modern houses require a continuous installation of fire detector. Not only industry, but also in the household. Take the case of a duplex that experience a fire accident without a detector that means everything in that building will get burnt even human beings. But in a case whereby fire alarm is installed that means everyone in that building will be alerted and also fire security bodies will also be informed for quick security action. The same thing can also happen to our offices and industries. In order to notify residence of any building in the presence of fire accident, a fire alarm system is used.

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 classified as either automatically actuated, manually actuated, or both. Automatic fire alarm systems are intended to notify the building occupants to evacuate in the event of a fire or other emergency, report the event to an off-premises location in order to summon emergency services, and to prepare the structure and associated systems to control the spread of fire and smoke.

1.1                           OBJECTIVE OF THE PROJECT

The objective of this work is to construct a device that will detect the unwanted presence of fire by monitoring environmental changes associated with combustion.

1.2                                SIGNIFICANCE OF FIRE ALRM SYSTEM

The primary advantage of a home fire alarm system is increased reliability and the ability to place alarms and bells exactly where needed. However, the reason most people have them is that they wanted a burglar alarm system and the cost of adding fire alarm features to a residential burglary system is relatively small.

Another advantage is that they are the only way to obtain remote monitoring services. This becomes important in cases where family members may not be capable of escaping from a fire without assistance. For example, if you have an older or physically impaired person in your home and a fire started when no one was home to assist that person, alarms alone might not be enough to assure their safety.

A feature of most monitoring services is the ability to keep special information on the residence which comes up on the computer screen whenever an alarm is received from that home. Thus, if there is a disabled person in the home who needs special assistance this fact will be known to the operator and can be passed along to the fire department when they are called.

1.3                                PURPOSE OF THE STUDY

The purpose of this work is to build a circuit that detects the fire and activates the Siren Sound or Buzzer. This device is very important devices to detect fire in the right time and prevent any damage to people or property.

1.4                         APPLICATION OF THE PROJECT

Fire alarms are prime necessities in modern buildings and architectures, especially in banks, data centers and gas stations.

1.5                                              SCOPE OF THE PROJECT

They detects the fire in ambiance at very early stage by sensing smoke or/and heat and raise an alarm which warns people about the fire and furnish sufficient time to take preventive measures. It not only prevents a big losses caused by deadly fire but sometimes proves to be life savers. The major components of this device is 555 Timer IC and thermistor which is the sensor –  which will sense the fire (temperature rise in surrounding), and trigger the alarm.

1.6                               PARTS OF FIRE ALARM

Fire alarm composed of the following parts:

• Primary Power supply: Commonly the non-switched 240 Volt Alternating Current source supplied from a commercial power utility. In non-residential applications, a branch circuit is dedicated to the fire alarm system and its constituents. “Dedicated branch circuits” should not be confused with “Individual branch circuits” which supply energy to a single appliance.
• Secondary (backup) Power supplies: This component, commonly consisting of sealed lead-acid storage batteries or other emergency sources including generators, is used to supply energy in the event of a primary power failure.
• Initiating Devices: This component acts as an input to the fire alarm control unit and are either manually or automatically actuated. Examples would be devices pull stations, heat detectors, or smoke detectors. Heat and smoke detectors have different categories of both kinds.

1.7                                         METHODOLOGY

To achieve the aim and objectives of this work, the following are the steps involved:

1. Study of the previous work on the project so as to improve it efficiency.
2. Draw a block diagram.

• Test for continuity of components and devices,

1. Design and calculation for the device was carried out.
2. Studying of various component used in circuit.
3. Construction of the circuit was carried out.

• Finally, the whole device was cased and final test was carried out.

1.6                                         LIMITATION OF THE PROJECT

The amount of “smoke” present may be insufficient to alarm smoke detectors. Smoke detectors are designed to alarm at various levels of smoke density. If such density levels are not created by a developing fire at the location of detectors, the detectors will not go into alarm.

• Smoke detectors, even when working properly, have sensing limitations. Detectors that have photo-electronic sensing chambers tend to detect smoldering fires better than flaming fires, which have little visible smoke. Detectors that have ionizing-type sensing chambers tend to detect fast flaming fires better than smoldering fires. Because fires develop in different ways and are often unpredictable in their growth, neither type of detector is necessarily best and a given type of detector may not provide adequate warning of a fire [4][5].
• Smoke detectors are subject to false alarms and nuisance alarms. For example, a smoke detector located in or near a kitchen may go into nuisance alarm during normal operation of kitchen appliances.

In addition, dusty or steamy environments may cause a smoke detector to falsely alarm. If the location of a smoke detector causes an abundance of false alarms or nuisance alarms, do not disconnect the smoke detector; call a professional to analyze the situation and recommend a solution.

• Smoke detectors cannot be expected to provide adequate warning of fires caused by arson, children playing with matches (especially within bedrooms), smoking in bed, violent explosions (caused by escaping gas, improper storage of flammable materials, etc.
• System components will not work without electrical power. If system batteries are not serviced or

Replaced regularly, they may not provide battery backup when AC power fails.

• Environments with high air velocity or that are dusty or dirty require more frequent maintenance.
• In general, fire alarm systems and devices will not work without power and will not function properly unless they are maintained and tested regularly.

The most common cause of an alarm system not functioning when fire occurs is inadequate maintenance.  As such, the alarm system should be tested weekly to make sure all sensors, transmitters, and notification devices are working properly [3][4].

1.9                                                         PROJECT ORGANISATION

The work is organized as follows: chapter one discuses the introductory part of the work,   chapter two presents the literature review of the study,  chapter three describes the methods applied,  chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.