Technology trends in fire detection and alarm systems
Release time: 2016-05-27 Browsing times: 1881
The fire protection community has come to see fire detection and alarm systems in a new light. Fire protection engineers, fire officials, and building owners have gained a new appreciation for the cost-effective role that fire-alarm systems play in protecting buildings and their occupants from fires. Recent technology advances to fire alarms include individual smoke detector sensitivity adjustment,drift compensation, and maintenance-needed indication. Such features reduce the nuisance alarms from these systems and, at the same time, shorten the time it takes alarms to detect actual fires.
The use of these so-called "smart systems" is being extended to buildings of all sizes as fire protection professionals come to understand the benefits they can provide-in small as well as midsize and large buildings. By some estimates, the use of addressable smoke detectors has increased to the point where they now account for more than 50% of the total nonresidential market.
The effectiveness of these systems is also increased due to the competency of people engaged in the detection and alarm business. The level of competence of the people who design, install, and maintain these systems-and of the officials who inspect them-continues to improve. That´s due, in large measure, to the quality and effectiveness of training programs conducted by the Automatic Fire Alarm Association, the National Fire Protection Association, and the Joint Apprenticeship Training Program of the IBEW/NECA.
Intelligibility of voice alarm systems The need for standards rose with the application of fire alarm systems that use recorded and live-voice messages for emergency notification. It extends beyond high-rise buildings to health-care occupancies ("Dr. Firestone, you´re wanted on the third floor, east wing."), malls, stadiums, and other large places of public assembly. Those standards should apply to intelligibility, which relates to speech clarity, as well as loudness. Ultimately, the intelligibility of voice messages determines whether it´s distinguishable and understandable to the people hearing it.
Concern for intelligibility will focus on the specifications for amplifiers and speakers. Just as important are the effects on individual, job specific system design. Factors, such as sound reflections and reverberation will need to be considered in system designs. This will alter the required skill set for system designers, installers, and also for the fire officials who will inspect these installations.
Integrating fire alarms As the interest in integrated building systems gains momentum, the fire alarm industry is starting to define ground rules for maintaining the dependability of the detection and alarm components when they are integrated with other building systems. Safeguards need to be defined to assure that a person on a terminal in the human resources department, for example, does not mistakenly access the fire alarm system via a LAN and leave portions of it disconnected. There needs to be assurance that such LANs will be monitored for integrity, making sure faults that might impair the detection and alarm function are promptly reported to the fire alarm system. If there is heavy, nonfire related traffic on the LAN, fire alarm signals must take priority.
The involvement of a nationally recognized testing laboratory (NRTL), such as Underwriters Laboratories, is also needed to assure the integrity of these integrated systems. Members of the fire alarm industry must adopt a standard communication protocol such as BACnet before these systems achieve integration. The industry is presently working toward that end.
Expanding the role of fire-alarm systems As fire-alarm systems become more integrated with other building systems, their role will likely expand beyond detecting fire and notifying building occupants and the fire service. For example, the sensor presently used to contro l lighting in a room (and also security) can be used to indicate to firefighters responding to a fire that a room is unoccupied, sparing them the time and danger of checking that room for a potential rescue. The security switch on a door can also be used to confirm to firefighters, responding to a working fire, the integrity of fire doors.
Testing sprinkler systems could simply be automated by installing solenoids on the inspectors´ test valves in a building and operating them from a timer in the fire alarm control. The sprinkler flow switch would confirm satisfactory sprinkler operation into a log or would automatically report a faulty sprinkler to building maintenance. Automating the sprinkler testing would likely elevate the reliability of these already very reliable systems and, at the same time, reduce the cost of testing.
In-duct smoke detection NFPA Standard 90A and the three model Mechanical Codes-which were developed by the model building code groups-BOCA, SBCCI and ICBO-all require smoke detection in certain duct work of building HVAC systems to shut down air handling equipment during fires. Smoke detection restricts the spread of smoke by these systems. Because there is no consensus as to when and where this detection should be installed, the Fire Detection Institute, a consortium made up of fire detection equipment manufacturers, users, insurance industry representatives, and other members of the fire protection community, has just accepted proposals for some in-depth research. The research will focus on smoke movement in ductwork and on the optimum location for smoke detection. The Fire Detection Institute´s research initiative shows the fire protection community´s commitment to improving the art of fire detection.
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