Depending on the expected fire situation, structures and type, quantity and occupants (health care, business, residential, industrial, and day care), and criticality f contents and mission, these systems can offer multiple key functions to aid in the safety of the occupants (Department of Veterans Affairs (Office of Construction & Facilities Management) , 2011). Their first two functions are the most vital. The first being a way to identify a fire hazard as it transpires through either manual or automatic methods. Secondly, It alerts the structures occupants to an Imminent fire hazard and the need to withdraw from the building.Another common function in a non single family structure is to send an emergency alarm notification to the local emergency response organizations. Some systems are even designed to sensitive systems to help in aiding in stopping the fire from spreading or reaching vital systems/areas by shutting down electrical power, air handling equipment and/or some or all automatic suppression systems.
The following sections further explain the basic features of commonly used fire detection and alarm systems in most non single family structure. Control Panels The control panel is considered the “brain” of the system.The primarily responsibility is monitoring and controlling the numerous alarm “input” devices manual and automatic detection modules) and then triggering the appropriate alarm “output” devices (horns, bells, warning lights, emergency telephone dialers, and building controls) (Agony, 2008). Control panels often run the gambit from single input and output units, to high-tech computer systems that can monitor numerous structures that spread out over campuses depending on requirements. The two most common control panel designs are conventional and addressable.Both of which are further detailed below. Control Panel: Conventional System In a conventional system one or more circuits are commonly channeled through unused and out of the way spaces of the structure such as the crawl space, interstitial floor, drop down ceiling space, etc.
). Along each circuit predetermined amount of detection devices are positioned. Selections of type and location placement of these detectors are reliant on upon a wide range of conditions to include initiation type (automatic or manual), ambient temperature and environmental conditions.The desired systems are usually positioned along a circuit at specific points to address the specific requirement for that area. Once fire hazard is identified, all detectors in the vicinity of the hazard will operate.
The device rips or closes the circuit and consequently notifies the fire control panel of a potential situation. The panel will then trigger the appropriate signal to active the structures alarms and send for help. Some panels are also able to signal to additional panels thus allowing the event to be monitored from a remote point.The primary advantage of this type of systems lays in their ease of installation in most small to intermediate size structures. Also, servicing these systems generally requires a small degree of specialized training. The major disadvantages of conventional systems tends to be that they are inherently labor intensive and expensive to maintain and in larger buildings are not cost effective due to the expensive to installing the copious amounts of wiring that would be required to accurately monitoring these devices.
Another disadvantage would be that each individual device usually requires some type of periodical operational test to ensure that it remains in operational state. This type of system has no accurate method of determining which elements are in need of servicing. Subsequently, each individual unit must be removed and serviced (a timely, labor intensive, and costly endeavor) to identify which unit needs to be repaired/replaced. Control Panel: Addressable Systems Addressable systems embody the current high-tech systems in this field.These systems control each alarms initiating and signaling element through the combined use of microchips and system software. Basically, each unit is a small computer to oversee the operation of the input and output devices (Artic, nun).
Comparable to the conventional system, the addressable system is arrayed throughout a space or building and can also installed on a series of circuits. However, the main differences system, each initiating device (automatic detector, manual station, sprinkler water low switch, etc. ) is given a specific identification or “address”.Nick Artic (nun) explains in, An Introduction to Fire Detection, Alarm, and Automatic Fire Sprinklers, that these addresses are likewise programmed into the “brain” with the following information: type of device that is connected, its location compared to the control panel, and prescribed response to each condition it experiences. Artic further goes on citing that “the control panel’s microprocessor sends a constant interrogation signal over each circuit, in which each initiating device is contacted to inquire its status (normal or emergency).This active monitoring process occurs in rapid succession, providing system updates every 5 to 10 seconds (Artic, nun).
” The addressable system also monitors the condition of each circuit and device. Thus allowing the system to identify any faults and their specific identity and therefore, eliminating the major disadvantage of the conventional systems. This also permits for a quicker diagnosis of faulty devices and repair. Artic (nun) also points out several advantages of this type of system such as stability, easier maintenance requirement, and simplicity of modification.Stability is primarily achieved by the yester software. Modifying these systems (adding or deleting a unit) consist of attaching and/or eliminating the desired unit from the circuit, and altering the suitable data in the control panel. This data change can be done at the control panel or on a laptop linked into the system. The one of the primary disadvantage of addressable systems is that each system has its own unique operating characteristics.
This requires service technicians to be trained for each type of addressable system.The type of training program is typically takes about 3-4 days of training by the respective manufacturer. It will also require update training from time to time to incorporate new service methods are developed. Fire Detectors Individuals tend to be exceptional fire detectors when present.
A healthy individual should be capable of detecting several facets of a fire such as the heat, flames, smoke, and odors. This is the main inspiration that caused the fire alarm systems to be designed with some type of manual alarm.However this is only a viable option of fire detection if the person is present when a fire starts.
There is also a chance that they some people might not raise an alarm in the required manner to ease the alarm efficiently, or they may have impaired sense to recognize fire hazards. Therefore this is the leading causes that lead to creating an assortment of automatic fire detectors. Automatic detectors are designed to emulate a variety of the senses such as touch, smell or sight. Therefore it is vital that the properly selected and installed automatic detector is properly utilized.Fire Detectors: Thermal Detectors Thermal detectors are among the oldest and most common type of automatic detection device (dating back to about in the mid sass’s) with similar models still in use today. The most commonly utilized detectors are the fixed temperature devices that historically function when the targeted area approaches a prearranged temperature (usually in the 1350-OFF/570-ICC). The next most common type of thermal sensor is the rate-of-rise detector, which recognizes an uncharacteristically rapid temperature rise over a predetermined time (Agony, 2008).
These units are also known as “spot type” detectors that requires sporadically spacing along a ceiling Handbook (Richardson & J. Roux, 2013). The third most common style is a fixed temperature line detector, which utilizes two cables with an insulated outer layer hat is intended to disintegrate when encountering a certain degree of heat. The primary advantage to this type is that the level of disintegration can be adjusted at a fraction of the cost in increase or decrease sensitivity.There are several other advantages to using thermal detectors such as they are highly reliable, have good resistance to operational wear and tear, environmental factors, and easy and cost effective to maintain. On the flipped, they tend to remain nonfunctional until the area temperatures have meet or exceeded the predetermined temperature that is usually a fully developed fire with rapidly growing damage to property. Fire Detectors: Smoke Detectors Smoke detectors are a much newer technology and have gained wide usage (about a century after the use of fire detectors. The sass’s and sass’s saw a huge up sing of usage in residential and health care applications.
This type of detector was created to simulate the sense of smell by identifying a fire in its earlier stage of smoldering. The most common smoke detectors are spot type units that are placed along ceilings or high on walls in a manner similar to spot thermal units. Smoke detectors primarily utilize either an unionization or photoelectric principle depending n their intended application and location.Large open spaces (galleries, foyers, halls, and lobbies) often used smoke detector such as a projected beam unit. This type of unit utilizes a low intensity laser that is mounted at equal intervals apart.
As smoke travels to intersect the laser, the transmitted beam becomes blocked, thus lowering the beam intensity and triggering the smoke alarm (Artic, nun). The most important advantage of system is to recognize a hazard in one of its earliest stages. Therefore, they are crucial for early and rapid response to mitigate property and arsenal damage to occur.They are frequently favored detection system utilized in most health care facilities and high value avenues. The primary drawback of this system is the comparatively expensive install price when compared to other systems.
Fire Detectors: Flame Detectors Flame detectors rounds out the major type of automatic detection method cite here. This type of detector closely imitates the sense of sight. Therefore, there detection abilities are limited to anything inside their sight angles that register on infrared, ultraviolet or combination principle depending on type (Department ofVeterans Affairs (Office of Construction & Facilities Management) , 2011). This device measures radiant energy and at approximately 4,000 to 7,700 angstroms range occurs (suggestive of a fire) their sensing element identifies the potential hazard and activities the alarm (Agony, 2008).
The main advantage of this type of system is their extreme reliability in most environments. Primarily their used in critical energy and transportation situations where other types tend to trigger false alarms.Some of these more common applications include public transportation maintenance facilities, refineries and hazardous loading platforms.
The major disadvantage of this system is the intensive cost and labor to maintain. Another liability is that they have to be focused directly at the hazard to detect it, unlike the other two types of detectors that can identify drifting fire signatures. Alarm Output Devices emergency is in progress which is a vitally important purpose of this type of device. Most devices notify two groups at the same time, occupants and emergency agencies.The occupants are generally signaled via audible and/or visual alerting components. Bells are the most commonly used alarm sounding device.
Horns are more common in areas where a loud alarm is needed such as warehouses, machine shops, and other heavy industrial places. Chimes are often utilized were a soft alarm tone is preferred to limit panic and confusion in health care facilities and theaters. Speakers are another option, which generally broadcast a prerecorded message or in a few cases a live message (Agony, 2008).Some systems also produce a visual alert by way of a strobe and flashing lights.
Visual alerting is required in spaces where the back ground noise levels are high enough to prevent hearing sounding equipment, ND where hearing impaired people may be found. Standards such as the Americans with Disabilities Act (DAD) mandate visual elements in most public building (Richardson & J. Roux, 2013).
As mentioned earlier one of the primary functions of the output device is notify the emergency response agencies.This is usually accomplished by either an automatic phone or radio signal that is sent to a continuously staffed emergency monitoring center. Once received the center will then inform the proper fire department and medical crew and provide pertinent information about the alarm. In some cases, the center may be the police or fire departments, or a 911 center. In other cases it will be a civilian monitoring establishment that is under contract to the parent organization such as with a large university or corporation such as Boeing, Microsoft, etc.
Summary In conclusion, there are a number of options for a structure’s fire detection and alarm system that are dependent on several key factors. These factors include the building construction (shape and size) and its value (to include contents), its use or uses (commercial, residential, or industrial), the type of occupants (residential, health are, child care, or business), mandated standards (DAD, NAP, building code, and so on), and mission sensitivity.