By Allan B. Colombo
From the April 2018 Issue
Those who work in and visit high-rise office buildings, warehouses, petroleum storage facilities, electric power plants, and other sizable structures and outdoor work areas are commonly subject to safety and security issues beyond their control. This includes the potential of injury and death due to fire and explosion. Corporations typically spend sizable sums of money in an attempt to minimize the risks.
For example, according to the National Fire Protection Association (NFPA) of Quincy, MA, in 2016, there were 1,342,000 fires reported in the United States which caused 3,390 civilian deaths; 14,650 civilian injuries; and $10.6 billion in property damage (http://bit.ly/2pp2KK0). In addition, last year, 25 fires alone in the U.S. resulted in losses of at least $10 million each, for a cumulative total of $1.4 billion in direct property loss (http://bit.ly/2pphfOK).
Fire detection in commercial and institutional properties usually consist of traditional, code-compliant fire alarm systems. These systems commonly include 1) spot-type detectors, such as smoke detectors as well as heat, rate-compensation, and rate-of-rise sensors; 2) line-type detectors, such as photoelectric projected-beam smoke detection and ProtectoWire-type temperature-sensitive cable; and 3) volumetric detectors, such as air-sampling smoke/fire detection systems, infrared (IR) flame detectors, combination flame detectors, and others.
All of these devices commonly feed data to a central fire alarm panel where they are analyzed and acted upon when there appears to be a fire somewhere in or outside the building(s). Through the utilization of a data-driven, addressable technology, each and every device can be monitored for supervisory and alarm conditions, which is usually reported to either a UL/FM-listed proprietary, supervisory, or central station facility where there are operators on duty 24/7.
Today, there’s another volumetric detection technology available that has largely gone unnoticed or ignored by many architects, electrical engineers, professional engineers, NICET Level IV professionals, and others—the individuals who customarily engineer the listed, code-compliant fire alarm system in buildings today. This relatively recent technology, called Video Fire Detection (VFD), involves the use of video surveillance cameras along with analytical software designed to detect the ensuing smoke (Video Image Smoke Detection [VISD]) and flames (Video Image Flame Detection [VIFD]).
In this article, we’ll take a look at this video-based fire detection technology. We’ll discuss how it works, where it’s commonly deployed, how and where to employ it, and we’ll look at how VFD fits into the overall picture as defined by NFPA.
Traditional Versus VFD
Because of the nature of video technology, especially that which contains the necessary analytical software to detect smoke and flames, the environmental conditions necessary to realize the full potential of VFD technology includes buildings with large rooms and high ceilings, such as warehouses, atriums, indoor or outdoor sports stadiums, scrap yards, airports, and manufacturing.
Where traditional fire detection devices typically monitor well defined areas around a single detector/sensor or in between detection devices, VFD detectors have the ability to detect a fire within the entire field of view (FOV) of a VFD camera.
Common smoke detectors, for example, are designed, tested, and listed to detect fires in a 30-foot radius around each detector. Fixed heat sensors commonly detect within a radius of 50 feet, and photoelectric projected beam-type smoke detectors can detect smoke at distances of 50 to hundreds of feet, depending on the design and specifications associated with the detector.
There’s no denying that VFD cameras are a departure from the norm. Most VFDs, as previously stated, are capable of detecting a fire anywhere within the camera’s FOV. The primary problem associated with this, however, is that changes in the environment that take place after the initial installation can and often will impede or prevent detection of a fire in progress.
“One potential issue with video-based fire detection is the line of sight of the camera. A flame hidden from camera view by any object would likely cause some amount—even short—delay in detection. This particular issue is without an equally probable case in typical smoke and heat detection strategies,” says Michael Minieri, principal security consultant & SME in physical security and fire/life safety with Minieri Associates of Orlando, FL.
Because of the propensity for changes in any environment over time, NFPA 72 also stipulates that all VFD fire alarm systems must be visually inspected quarterly whereas traditional fire alarm systems are required to be visually inspected every six months. Table 126.96.36.199(h), 2013 Edition, says, “Verify [that] no point requiring detection is obstructed or outside the detection field of view.”
How VFD Systems Work
At the forefront of every VFD system is an analytical software capable of detecting smoke and the flame of a fire. According to Soeren Wittmann, product manager with Bosch Security Systems, Inc. of Fairport, NY, the VFD product that his firm offers, called AVIOTEC, features an algorithm “…based on the physical characteristics of fires. It detects flames and smoke within an incredibly short time span by analyzing video sequences. In case of flame or smoke detection, the video broadcast has the advantage to verify the alarm, speed up the rescue chain and give insights to rescue teams.”
In this case the analytical software is built into the camera on the edge of the network. Connection with the local fire alarm system usually occurs at the VFD camera, unless a VFD server solution is used (more about this later).
Most VFD manufacturers will tell you that there are individual analytical softwares within each camera—one for smoke detection, one for flame detection, and sometimes (but not always) one for ordinary security applications, such as directional motion and object-left-behind detection.
“In the most basic sense, video analytics’ algorithms for smoke detection monitor the image for movement of light patterns relative to a stable background. If the movement is consistent with known smoke movement patterns, and preset alarm zone, sensitivity and time-delay thresholds are met, then an alarm is generated,” says Rick Jeffress, business development, facilities protection group with Fike Corporation of Blue Springs, MO. “For flame detection, the analytics are monitoring the same stable background and looking for groups of pixels indicating slow changing brightness accompanied by known dynamic flicker signatures.”
Some VFD systems, such as Bosch’s, feature traditional security detection features as well as fire.
Supplemental Versus Primary VFD
There are two types of VFD systems on the market today: Primary and Supplemental. Primary protection uses third-party listed components—listed by Underwriters Laboratories (UL) or Factory Mutual (FM)—that specifically are tested for full-fire code (primary) compliance. This includes alarm and supervisory alerts. The latter is used to get attention when something inside a listed VFD camera/system is not working.
For comparison, supplemental protection entails the use of non-listed video components that have the ability to detect smoke and flames but cannot report internal supervisory problems. Both types of VFD are defined in NFPA 72, entitled National Fire Alarm and Signaling Code, which is adopted by almost every municipality and state within the United States.
According to Kenneth Oberst, SET, southern regional support representative with Hochiki America of Buena Park, CA, NFPA defines primary Video Image Smoke Detection (VISD) as “The principle of using automatic analysis of real-time video images to detect the presence of smoke” (Section 3.3.269.5, NFPA 72, 2013 Edition). Oberst says that NFPA also authorizes the use of supplemental protection in Section 188.8.131.52, NFPA 72, 2013 Edition: “Supplemental notification shall be permitted to provide additional information or more detailed instructions than those transmitted by the primary notification means.”
NFPA 72, for informational purposes, specifically addresses how to install all fire alarm system types, including listed VFD cameras/systems. In the section entitled “Important Notices and Disclaimers,” it states that “NFPA codes, standards, recommended practices, and guides (‘NFPA Documents’), of which the document contained herein is one, are developed through a consensus standards development process approved by the American National Standards Institute (ANSI).”
Says Oberst, “The most common video fire detection system on the market today involves supplemental protection. This means that a supplemental video fire detection system provides a second opinion of sorts to that of a primary detection system. The latter is comprised largely of traditional detectors, such as photoelectric beams, smoke detectors, and heat sensors. The VFD component is installed above and beyond what’s actually required.”
Joining the fire detection mission with alarm verification also assures that when a supervising or central station calls a local fire service to request fire department response, there’s really a fire to fight. Otherwise false alarm fines can and often are levied against the facility in question. VFD systems, whether they are primary or supplemental, are a valuable commodity from this point of view.
“Connecting [a VFD] camera to a video management system offers the possibility to find out the cause of fires. Based on video recordings, incidents can carefully be established and evaluated. This helps eliminating and preventing hazardous situations in the future,” says Bosch’s Wittmann.
Potential Benefits of VFD
One of the advantages of using VFD technology, whether it’s supplemental or primary, is that detection is relatively quick compared to traditional smoke detection systems. For example, in a high ceiling, warehouse application, there’s usually projected-beam detectors atop the ceiling. Smoke must actually reach ceiling level—and in enough quantity—for alarm detection to occur. This can take considerable time because of air stratification, especially when the fire is in its incipient stages.
Listed, fully-compliant VFD technology also can be more economical than projected-beam detectors. For example, in a warehouse setting, photoelectric projected-beam detectors are usually spaced 60 feet apart—30 feet to each sidewall (in accordance with the manufacturer’s installation instructions). If the distance from sidewall to sidewall is 600 feet, there will be approximately 10 photoelectric projected-beam detectors. Using the VFD route might require two or three cameras—maybe one depending on the areas of interest for detection purposes.
Another issue that makes fully-compliant and listed VFD technology attractive is the fact that the analytical software in use will often allow the installer to specify zones of detection so when a fire does occur, the local fire department has at least an idea what portion of the facility to address first.
“An example of configuration flexibility is the ability to set specific areas within the camera view as alarm zones; the analytics monitor and track the camera view and, when smoke breaks the plane into the alarm zone, an alarm is generated,” says Fike Corporation’s Jeffress. “Alarm zones allow us to specifically target areas for alarm. This strategy can also be used in aircraft hangars or outdoor chemical processing with flame detection by targeting specific areas of possible flame, while monitoring—but not alarming—in areas with false alarm potential.”
It’s also possible to utilize existing video surveillance cameras to provide early warning of a fire using an unlisted supplemental VFD network server.
“If the existing video surveillance system uses IP cameras, by adding a VFD server it’s possible to monitor large areas with high ceilings for fire. Also, if the existing video system uses analog cameras, encoders can be added to convert the video signals into digital data, as in a traditional IP camera system,” says Oberst. “In this type of application, however, you cannot remove the photoelectric beam-type smoke detectors because they’re listed and compliant with fire code while the aforementioned unlisted video fire detection system isn’t.”
As mentioned earlier, supplementary VFD then acts to support the existing traditional fire alarm system with the exception that VFD offers the potential of rapid, early detection. Many times this is integral to saving lives because seconds count.
“All codes clearly state that they are ‘minimums’ and that nothing prevents one from exceeding them. As long as the system is first fully compliant, the additional measures—being nonrequired—are not subject to enforcement,” says Minieri.
While supplementary VFD technology can be an excellent addition to an existing fire alarm system, primary VFD can actually replace the use of traditional fire detection. In large facilities with high ceiling, even in outdoor applications, VFD can save a significant amount of money simply because a limited number of these types of cameras will perform the same task as an armada of traditional fire detection devices.
Colombo, a recipient of the prestigious Jesse H. Neal Award, is a longtime trade journalist in the security and life safety markets. His articles have appeared in locksmith, security, and fire-related magazines since the mid 1980s. He can be contacted via his website, www.Tpromo.Com.
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