ABSTRACT
Despite many buildings have fire fighting systems installed in them; many people are still losing their lives and properties due to fire accidents. In this research, an automatic cost effective device for the detection and control of fire has been designed and constructed. The system has an additional feature of sending signal to a pump/sprinkler through a relay. It is made up of two sensors, microcontroller, buzzer and a controlled fire fighting equipment (pump/sprinkler). LM 35 IC has been used as temperature sensor while MQ-2 gas sensor has been used as smoke sensor. All sensors are connected to the microcontroller through an input/output port. The controlling software for the whole system was designed in C programming language. The popular high performance, low power 8-bit microcontroller from the AVR family microcontrollers was used. The system was finally tested by introducing fire parameters (smoke and temperature) close to the detectors. When the parameters go above the set level in the detectors, audio alarm, LED indicator and pump/sprinkler were activated. The measured temperature of the system was compared with the reference temperature. The result showed that there was a mean deviation of 1.550C between the measured values and
reference values which served as the control.
CHAPTER ONE
INTRODUCTION
1.1 Background to the study
The need for early fire detection is paramount in protecting human life and property as fire disaster is a great threat to lives and properties. Fire is the rapid oxidationof a material in the exothermic chemical process of combustion, releasing heat,light, and smoke. It is understood that every fire start with a smoke and heat. A key subject of interest to many researchers has thus been on fire fighting systems. More interest has been given on automation of these systems to allow fire fighting operation be less dependent on human support. Automated fire fighting system, which depends on temperature and smoke sensing devices, is used in many industrial and commercial applications. It is however true that in most cases sensible heat often occurs after great destruction has occurred and thus the use of smoke sensors need not be ignored at any point whatsoever. A number of fire detectors have been designed that can be installed within buildings. Among these types of sensors, the smoke sensor is widely used because of its early fire detection capability and its relatively low cost (Richard et al., 1998). However, although this sensor provides rapid response time, it has high false-alarm rates. In contrast, the temperature sensor provides more reliable responses but with slow response time. Fire detectors that use a single sensor may fail to activate when required or may cause false alarms. Therefore, a fire detecting system that uses a combination of smoke and temperature sensors will not only provide better smoke sensor compensation but also provide a more intelligent fire control system (Cheon et. al., 2009).
The need to safeguard lives and properties from fire disasters has led to the invention of an automatic fire control system using a smoke detector, a heat detector and an automatic sprinkler (Bukowski et. al., 1999). Automatic fire alarm system provides an immediate surveillance, monitoring and automatic alarm. It sends early alarm when the fire occurs and helps to reduce the damage (Zhang and Wang, 2009). A smoke and heat detector is one of the numerous ways of detecting fire outbreak at an early stage, while a water sprinkler is the most common way of extinguishing fire. An automatic fire control system is an electronic circuit designed to control a sprinkler which produces water or any extinguishing element, when it detects the presence of smoke and excessive heat (Bukowski et. al., 1999).
The automatic fire control system brings out efficient automatic fire detection and extinguishing system. The fire detection sensors will sense the occurrence of fire, by monitoring smoke and heat, which automatically generate a signal to interrupt the microcontroller which is connected to a buzzer and a pump. Suddenly after detecting the fire, the buzzer automatically sounds to indicate the presence of fire and starts the relay which runs a pump and pressurizes the extinguishing element to suppress the fire using water sprinkler. The role of the control unit in improving fire detection and control capability has already been recognized, with a system using control unit for decision making being one of two main versions of intelligent fire detection systems (Liu et. al., 2008).
Automatic fire control systems have been made and installed in our buildings, which performed its specific functions accordingly. Both system activation (detection) and notification (alarm) must occur to achieve early warning (Bukowski et. al., 1999).
1.2 Statement of the research problems
The need for people to protect their lives and properties from fire disaster cannot be overemphasized. Today, the incidence of fire outbreak in our homes, offices and industries are increasing. An uncontrolled fire can destroy an entire room contents within few minute and completely burn out a building in a couple of hours. Most of the fire outbreaks occur when the occupant is not at home or sleeping. As these problems need instant human intervention to avoid it, automatic fire detection and control system become necessary in our buildings. The majority of fire fighting systems are manually operated, which cannot be reachable during fire outbreaks. Manual fire fighting systems, though are relatively cheap and do not require any power supply are however associated with the problem of non-controlling fire outbreak without human intervention. Furthermore, the automatic fire control systems available in modern buildings are very expensive and not affordable by most people, hence, the need for designing and constructing a cost effective automatic fire control.
1.3 Objectives of the research
The main aim of this research work is to design and construct a cost effective automatic fire control system.
To achieve this, the following objectives would be accomplished:
§ Design and construct a smoke sensing device.
§ Design and construct a threshold temperature sensing device.
§ Design and construct a control device to switch pump/water sprinkler.
§ Develop a computer program (software) to control the constructed system.
§ Produce an affordable automatic fire control system.
1.4 Significance of the study
Automatic fire control system finds application in every building that stands the risk of fire outbreak. These includes homes, filling station, large and small scale industries, store houses, school campus, airports, hospitals just to mention a few. Most of the fire fighting systems in Nigeria is manually operated. These systems, is mostly not very effective as fire incidents are often not detected early enough. In some cases the places requiring fire extinguishing are difficult to reach making it impossible for fire fighters. The main reason is manual operation of these systems which causes great challenge in their operation during fire accidents especially when they are located inside the building. System that detects fire parameters, give audio warning, activate water sprinkler will be a reliable system to control the fire accident.
All these are the key subject of this research.
1.5 Scope and Limitations
This research work undertakes the design and construction of an automatic fire control system, capable of detecting smoke and heat. It involves design of various units: power supply, sensing and control units.
However, it is hardly that anyone’s research is a complete study of any problem, let alone a postgraduate research work of this nature which is considerably limited by time and resource. This is why the system was constructed with materials that are cheap and readily available thereby making the cost of the system low and easily acquired. This will enable the use of the system throughout every category of person and firm. Coupled with the low cost, the size of the system is also small enough for convenience in installation.