DESIGN AND CONSTRUCTION OF FIRE ALARM SYSTEM IN A THW STOREYED BUILDING
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF THE STUDY
Today, humanity can be classified as living in a “machine society” where technological tools are predominantly at different levels, interfacing in the day–to-day activity of man. These livelihood activities constitute and deliver economic, social and political benefits and potential risks to the survivability of nations –especially developing nations like ours. Due to the fast development in telecommunication technologies, it is believed that wireless communication is a good practice for remote sensing and automation in industrial and residential locations. Nigeria, like any developing country, is witnessing an era of rapid economic and social development. This development brings with it, new technologies, new materials, power sources and telecommunication equipment. Modern industries are springing up housing volatile materials and highly sophisticated equipment that increase the menace of fire. Concerns for safety of lives and properties call for an efficient and dependable fire protection system using sensors. Sensors are able to consider certain dynamic and static variables such as humidity, the type of fuel, slope of the land, the direction and the speed of the wind, smoke , to mention a few.
The reports of most of the panel of enquiries on fire accidents in Nigeria, oral interview of some fire experts and personal experience confirmed the fact that electrical fault is a major source of fire accident. Hence, realization that a fire protection system capable of automatically switching off electrical power supply to the affected area in addition to the traditional role of raising an alarm and triggering a sprinkler or other automatic fire lighting system is going to be more efficient than the existing systems which leaves that important role unaddressed. Nowadays, automatic fire detection and control is becoming very essential to reducing fire outbreak in the building and industry. Automatic fire alarm system provides real-time surveillance, monitoring and automatic alarm. A key aspect of fire protection is to identify a developing fire emergency in a timely manner, and to alert the building's occupants and fire emergency organizations. This is the role of fire detection and alarm systems. Generally fire detectors are designed to respond at an early stage to one more of the four major characteristics of combustion, heat, smoke, flame or gas. No single type of detector is suitable for all types of premises or fires. Heat detectors respond to the temperature rise associated with a fire and smoke detector respond to the smoke or gas generated due to fire.
Thus, proposed in this paper is the design and implementation of a fire detection and alarm system, this idea is economically efficient as well because the system proposed is intelligent and reduces human intervention and labour extensively and execution can be gotten at a very low cost providing extensive environmental, property and life safety.
1.1 Statement of the Problem
The Nigerian environment is considered to be hazards prone brought about by man-made and natural disasters due to its geographic circumstance which is exposed to catastrophic, floods droughts and fires. Based on the reports; devastations of these natural hazards and disasters including fires have increased in recent years. Our lifestyle of negligence and adapting to emerging technological solutions puts us at the risk of loss to fire and related occurrences as seen in markets, homes and other public places. The risk of fire occurrence is high especially during the dry season, Christmas and New Year celebration due to firecrackers. In the case where house fires are prevalent, it has effect to derail the economic growth, destroy social and physical capital including infrastructures, which resort to reallocation of ongoing programs to finance relief operations to fatalities and inhabitants and reconstruction efforts which diverts funds to social services.
Fires are considered natural and manmade hazards. In existing system, fire prevention and fire suppression requires the manual notification by humans after which the fire men are called. This process is slow and destruction of lives and property is paramount. To curb the current menace due to fire outbreak, there is need to automate the fire detection process. This automated method involves the adoption of uniform fire safety standards, the incorporation of fire safety, construction and provision of protective and safety devices in buildings and structures. These technologies can accurately predict heat, smoke in a building and give alarm for immediate attention.
1.2 Aim and Objectives of the Study
The main aim of this project is to design and construct a real-time fire alarm system for a two storey building capable of monitoring the status of the environment and make a prompt remote response in case of a fire incident. To achieve the stated aim, the following specific objectives were laid out:
i. Design a system capable of detecting smoke and heat in a two storey building
ii. The system should produce alarms when fire is detected
1.3 Significance of the Study
The implementation of this system will go a long way in helping minimise the losses that arise due to fire outbreak in buildings. It is hoped that the fire alarm unit will find useful application in homes, offices, hospitals, restaurants, market places, service centres etc to reduce the outbreak of fire. This project will serve as a contribution to knowledge to scholars who are researching the field of fire alarms.
1.4 Scope and Limitations of the Study
There are two main parts tot eh developed fire alarm systems: The public fire alarm system and the private fire alarm system. The public fire-alarm boxes are connected to the fire station by dedicated lines. These alarms boxes also perform the function of relaying calls initiated from private fire detection system to the fire station automatically. The private fire alarm detections system are used to monitor particular limited properties. They are installed in among other places, offices and business premises, industrials and commercial undertakings, theatres, cinemas department stores, schools, old people homes, hospitals and hotels.
The fire detection system consist of the control centre including its power supply (mains equipment and battery) with the principal functions of indication control activating alarms and system management, the alarm units connected through call circuits, the monitored and unmonitored lines for controlling the local alarm and information equipment, the fire protection equipment and the circuit to the fire brigade.
The fire alarm units are in the form of automatic fire detectors or of press bottom alarm boxes. Base of these, we extended our attention on the form and nature of a fire alarm system that will give the desired result. Careful study was extended also to such areas as choice of components, portability, durability, economic choice and of course engineering efficiency. We also did our very best to ensure that the circuit wiring conformed with set standards with regard to requirements rules and regulations of electrical installation.
The position of the sensory unit of fire alarm system found convenient on the corridors, rooms, bath rooms or any strategic position where it is likely to be any fire outbreak. However, the sensory unit of the system should be kept at some convenient distance from the kitchen, because of the thermal characteristics of some of the relay component. Although, if installed in the kitchen should be well safeguarded against the heat that normally comes from the kitchen and should be at least 1.5 meters above the floor to avoid children’s reach.
1.5 Methodology
In the design of this circuit, much care was taken to ensure correct polarity which in effect determines the continuity of the circuit. This was also made possible by numbering each connections. Nevertheless, the approach to the design of this system involve trial and error methods. After the initial design was completed, the model was set up to task the behavior of the initial system configuration and was by no means satisfactory, and was re-designed and corresponding analysis completed. This process of design and analysis was repeated until a satisfactory workable system was obtained. Then a prototype physical system was constructed, built and tested to see whether or not it is satisfactory.
1.6 Definition of Terms
· Switch: A Mechanical switching device capable of making carrying and breaking current under normal circuit conditions, which may include specified time currents under specified abnormal circuit conditions such as those of short circuit. It is also used for economy reasons when conserving electrical power.
· Fuse: A fuse is a device for opening a circuit by means of conductor designed to meet when on excessive current flow. The fuse comprises of all the parts that form the complete device.
· 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.
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.
1.2 STATEMENT OF THE PROBLEM
The alarm is given locally (visually and audibly) in order to mobilize internal auxiliary personal e.g the works fire brigade) and inform them as to the seat of the fire. A control center performs the organization of the alarm, that is, it makes available operational aids for the fire fighting measures and automatically bring the fire protection equipment into operation.
