Fire detection and alarm systems have relied heavily on technology to detect smoke. However, other technology — essentially using computer software to analyze surveillance video — offers advantages over typical fire alarm systems and has been gaining more widespread acceptance and use.
Fire alarm systems that rely on traditional smoke and fire detection use various types of technology, such as air sampling smoke detectors or optical detectors, and they have continued to improve. A drawback, however, is that generally they rely on smoke or heat to travel to a device.
In most typical commercial and industrial applications, traditional fire detection equipment may work very well. However, large areas with high ceilings can undermine the performance of spot-type smoke and heat detectors and others.
Video image detection identifies the fire at the source and is especially effective in areas with high ceilings. In fact, the technology that analyzes the images is so accurate that it can differentiate between smoke and steam. Originally designed for mostly large facilities and outdoor settings, video image detection systems now are being used in a broader range of applications, including industrial buildings and warehouse and distribution centers.
Another technology that may be part of a fire detection system is thermal image cameras — cameras that can detect heat.
Generally, a video image detection system for fire prevention relies on video images from an analog or digital camera. An advantage is that they can utilize existing surveillance video cameras. The images are processed by software that uses analytical algorithms to identify smoke or flame. The algorithms can be based on various properties and characteristics of smoke and flame to analyze changes in brightness, contrast, motion, pattern and color matching, and other factors. Capabilities may vary from being able to detect only smoke or flame or both.
Video image detection systems for smoke require a minimum level of light to be effective; low-light cameras can improve performance, and some systems utilize infrared illuminators and infrared-sensitive cameras. In contrast, systems to detect flames are effective in light and dark, and some have enhanced detection capability for flame in the dark.
Initial video image detection systems consisted of several cameras connected via analog cable to a central processor. Advancements have resulted in a second type where the analysis is performed at the camera. They can store video footage and can be integrated with a closed-circuit video surveillance system with another processor, or can be configured as a ‘spot’ detector. The devices can be monitored remotely via network or Internet connections, too. Video of alarm conditions can be archived for each device and can be displayed automatically to monitors for instant viewing.
The National Fire Alarm Code recognizes the use of flame and smoke video image detection systems. Installation requires a performance-based design. Due to the variability of system capabilities and the differences in alarm algorithm technologies, the code requires systems to be inspected, tested, and maintained in accordance with the manufacturer’s instructions.
Some systems have little or no user definable settings and are almost plug-and-play. Others require a manufacturer’s representative to customize the system to the application. Once set up, little maintenance is needed. Similar to any field-of-view detector, the main concern is keeping the optical windows clean and the camera position fixed and unobstructed. Most systems monitor the video image and provide a warning if the image quality is degrading or not adequate for proper detection performance.
Video image detection systems provide unique advantages in a wide range of applications. One is the ability to protect a large area while still achieving fast detection, especially when it comes to systems for detecting smoke as compared to spot or beam smoke detectors. Conventional smoke detectors may not be practical in large buildings. Video image detection systems can detect smoke or flame anywhere within the field of view of the camera while conventional smoke detectors rely on smoke traveling to the detector.
The ability to use the system’s basic hardware (cameras and wiring) for other purposes is another advantage. Integrating a system with video surveillance minimizes certain costs for installation, maintenance, and service. It also can increase system reliability due to more frequent use of and attention to the video equipment.
Another advantage is that live video can be available immediately during a pre-alarm or alarm condition. Monitoring personnel can easily view the protected area to determine the extent and accurately identify the location. In the event of a nuisance alarm, the live video enables a better assessment and response.
The potential for nuisance alarms depends on the specific system and its technology. Some systems can be adjusted for sensitivity and time before an alarm is issued. Manufacturers also have developed specific alarm algorithms to prevent common nuisance events.
To sum up, video image detection for fire detection provides advantages over typical fire alarm systems in many applications. This technology is considered a significant step forward in fire protection.
A fire detection system may also include other equipment, such as heat detection cable or thermal imaging cameras. Thermal imaging technology can detect overheated equipment or components, notably hot spots in dust collection or conveying equipment, as well as heat from the initial stages of a fire developing under or in debris. The technology also can reveal incremental temperature changes over time in machinery and equipment.
Other sources of information you may want to consider include Fike Corporation (www.fike.com), a global business with headquarters in Missouri that specializes in solutions for detecting and preventing pressure, explosions, and fire, and NOTIFIER by Honeywell (www.securityandfire.honeywell.com/notifier/en-us), which also provides fire safety solutions.
You may also want to consider retaining the services of an independent fire engineer consultant.
In evaluating fire detection systems, consider whether they are UL listed or have been evaluated by FM Approvals as well as if they meet pertinent standards for fire safety and fire detection.
