Implementation of an Automatic Fire Detection and Alarm System
Chapter One
Aims and Objectives
The aims and objectives of this project are broken down into the following activities:
- To design a schematic representation of the whole system
- To design a power supply unit that supplies direct current (DC) sources of 5V and 12V independently.
- To design the sensor element for early fire detection
- To develop a program required to control the overall functioning of the microcontroller.
- To set up and integrate a high quality, voice record and playback chip with high efficiency rated speakers into the system
- To incorporate a sprinkler system into the overall system.
CHAPTER TWO
LITERATURE REVIEW
Introduction to Fire Alarm Systems
According to Vijay, G. and Elliot, S. in [5], the most basic alarm system is designed to only be initiated manually. This is a local warning system similar to the type installed in schools or theaters, and the signal alerts occupants of the need to evacuate the premises. While alarm standards have traditionally called this type a local system. A wide variety of optional features are available to expand the capabilities of an alarm system. Automatic fire detection devices may be added, allowing the system to sense the presence of a fire and to initiate a signal. There are four basic types of automatic alarm initiating devices which are designed to detect, heat, smoke, fire gases, and flame. These are briefly discussed below.
Heat or Thermal Type Detectors
Heat or thermal type detectors are the most primitive types of autonomous fire detectors, dating back to mid-1800. Nick Artem in [6] points out that most of these detectors are fixed temperature ones, which activates upon reaching a predefined temperature. Others include types, which activate whenever there is an abnormal rise in temperature in the premises.
Studies have shown that heat detectors are not as effective as smoke detectors in detecting fires in residential homes. Thermal detectors are reliable, inexpensive, easy to maintain, and have lower false alarm rate. However, these detectors are slow, and by the time they reach predefined detection point, damage could already been underway. Therefore these detectors are of limited use.
Smoke or Gas Detectors
Smoke or gas detectors, a relatively newer invention, became widespread during 1970’s and 1980’s.These detectors usually detect fire in early flaming or smoldering stages. They are of two main types—Optical or Photoelectric detectors and Ionization detectors [7].
Optical or Photoelectric detectors
Cote, A. and Bugbee, P. (1988) in [7] points out Photoelectric or optical smoke detectors include various components, mainly a light source (usually an infrared LED), and a lens to converge light rays forming a beam, into a photodiode. In normal condition, the light beam passes straight. However, when smoke distorts the path of light, it scatters fractions of light into the photodiode activating the smoke detector. This method of detection can detect fires that begin with long duration of smoldering.
Ionization detectors
Ionization smoke detectors are based on ionization from radioactive elements (americium 241). This radioactive isotope emits alpha particles into an ionization chamber, which comprises of electrodes. The alpha particles ionize the air inside the chamber, resulting current flow between the electrodes. Now, whenever smoke particles from a nearby fire passes through the chamber, the ions get attached to smoke particles, and thereby interrupts the current flow between the electrodes, and activates the detector [7].
According to National Fire Protection Association (NFPA) in [8], this type of detectors is more suited to rapid flaming fire outbursts, unlike the photoelectric detectors, which responds better to smoldering stages. Ionization detectors perform better where there is risk of fast flaming fire, whereas photoelectric detectors react better to cases of slow smoldering, like electrical or furnishing fire. Ionization devices are weaker in scenarios where air-flow is high.
W. Bukowski et al (2007) in [9] maintains that although ionization type detectors are cheaper than photoelectric ones, they have more chances of false alarm than the photoelectric detectors. However, ionization based detectors have safety issues and possess threats to environment, because of americium-241. Therefore, on the basis of performance and safety concern some countries have banned ionization based alarms, and different fire authorities and associations have reports not recommending use of these detectors [7].
Flame Type Detectors
Wikipedia, the Free Encyclopedia (2013) describes flame type detectors as sophisticated equipment used to detect the flame phenomena of a fire. These detectors have various types depending on the light wavelength they use. Such as, Ultra-violet, Near Infrared, Infrared, and combination of UV/IR type detectors [10].
CHAPTER THREE
METHODOLOGY
This project is aimed at designing and constructing an automatic voice prompt fire detector and extinguisher. The methodology used here would adopt a modular approach where the entire system is broken down in to separate sections. The design of the system is made up of the hardware design sections and the software design section. The hardware sections were designed and constructed separately while preserving the overall system requirements and specifications. This was achieved through schematic capturing, simulation and prototyping. This approach has one great advantage in which it allows user to interact with the system even if it is not ready for wide-spread organizational use. The different modules or section involved in this project includes:
- The power supply module
- The sensor module
- The control unit
- Notification appliance module
- Fire suppression unit
They will be individually highlighted and discussed in the next section of this chapter.
SYSTEM ANALYSIS/DESIGN
As stated earlier above, the design of this system involves the hardware design sections and the software design section. The separate modules of which have been listed in the previous section above are carefully integrated into the block diagram of the system.
The block diagram of the system is seen in the figure below:
CHAPTER FOUR
SYSTEM IMPLEMENTATION/RESULT ANALYSIS
SYSTEM IMPLEMENTATION
After a thorough analysis and design of the different modules evaluated in Chapter three, the system was test run on a bread board after which all the components and ICs were transferred to the vero board where they were soldered.
The vero boards were used to implement the circuits contained in the design of this prototype. The dot vero-boards were preferably used in this project because the problem of encountering continuity is reduced.
CHAPTER FIVE
CONCLUSION AND RECOMMENDATIONS
CONCLUSION
The Voice prompt fire detector and extinguisher are considered better alternatives to traditional audible alarms because a voice is typically less likely to instill panic, and the voice feature can be used to give specific instructions, for specific situations. They not only let everyone when an emergency arises but they also inform the people of certain measures to take to avoid confusion and thereafter saving them valuable time necessary for protection of life and properties.
Furthermore, the Voice prompt fire detector and extinguisher can be programmed to give voice alerts in diverse languages or dialects according to where it is being installed around the world. It clears the problems of families or communities who do not understand a particular global language or dialect. This thereby increases the number of lives saved since there are no excuses on the ground of not understanding a particular language.
In addition, the Voice prompt fire detector and extinguisher limits the spread of fire through the means of the water sprinkler system which removes the heat content of the fire (cooling effect) thereby extinguishing the fire.
LIMITATIONS OF THE WORK
- Getting the complete components needed for the project work was very tasking especially in getting the ISD170120PY Voice Chip. During the project the Chip developed a fault and needed to be changed. This posed a lot of difficulties since they were not readily available in the market and had to be ordered from abroad.
- Upon installation, the system energizes. This causes the alarm goes off each time the system is powered.
- Fire can only be detected when the system is powered. Therefore fire cannot be detected in a building where there is no power source.
RECOMMENDATIONS
- More time should be given to students by the school or departmental management to enable them have enough time to research more on their work and also enable them offer more efficient works. Moreover, since most unavailable components are shipped from abroad to Nigeria, more time is required.
- To prevent the alarm from always going off every time it is powered on, a microcontroller should be used to initialize the circuit. This means that the microcontroller delays the system or puts it on hold for a period of time for it to be properly triggered by an input value of the sensor.
- Since this system can only be functional when there is power supply, it should be modified to become battery powered or solar powered in order that it can be used at all times.
References
- “Home Fires”. Available: https://ready.gov/home-fires
- Evax Systems, “Why Voice Evac”? New Haven.
- Reliable Fire & Security, “Voice Evacuation”. Available: http://reliablefire.com/fire-protection/fire-alarms/voice-evacuation/ [Accessed 21st May 2016]
- Siemens Technologies, “Voice Alarm System E100 – The new standard for Safe evacuation”, Siemens Switzerland Ltd.
- Vijay Gehlot, and Elliot B. Sloane, “Software and System Engineering to Ensure Patient Safety in Wireless Medical Device Networks,” Villanova University, Copyrights© 2006 Gehlot and Sloane, accepted for Computer Magazine, April 2006.
- Nick Artim , “An Introduction to Fire Detection, Alarm, and Automatic Fire Sprinklers”. Northeast Document Conservation Center: Available at:
- http://www.nedcc.org/free-resources/preservation-leaflets/3.-emergency-management/3.2-an-introduction-to-fire-detection,-alarm,-and-automatic-fire-sprinklers
- Cote, A. and Bugbee, P. (1988). “Ionization Smoke Detectors, Principles of Fire Protection”. National Fire Protection Association, Quincy, 249.
- National Fire Protection Association, “Ionization vs. Photoelectric”. Available at: http://www.nfpa.org/safety%20information/for%20consumers/fire%20and%20safety%20equipment/smoke%20alarms/ionization%20vs%20photoelectric.aspx
