Fire Side Chat: Picture Perfect Fire Detection
The fire protection industry is an ever-changing environment. If it were not, fire codes would remain the same year after year, cycle after cycle, and our job would be less complicated.
Oftentimes, changes occur in the fire protection industry because of advances in fire detection technology, while other times it’s a catastrophe, such as the Feb. 20, 2003 nightclub fire in West Warwick, R.I., that killed 100 patrons and injured more than 200.
Changes in technology inevitably bring about new products, installation methods and innovative engineering techniques. For example, a new detection technology that has the attention of the fire protection profession is designed to utilize conventional or IP-based video cameras to monitor large spaces for smoke and/or flames. Respectively, these technologies are calledvideo image smoke detection (VISD) and video image flame detection (VIFD). Collectively we’ll refer to them as video fire detection, or VFD.
“Video smoke detection is making a major contribution toward improved fire safety in areas that have traditionally provided the greatest challenges for the earliest possible detection of smoke” (Chubb of Australia, a UTC Fire and Security Company, www.chubb.com.au).
Both VISD and VIFD technologies are defined in NFPA 72, 2007 Edition. In Section 3.3.209, VIFD is described as: “The principle of using automatic analysis of real-time video images to detect the presence of flame.” VISD is defined in Section 188.8.131.52 as: “The principle of using automatic analysis of real-time video images to detect the presence of smoke.”
In brief, the difference between conventional heat and smoke detection technologies and VFD is the former requires the smoke or flames to impinge directly on the detector where the latter is capable of detection at a distance. Let’s take a closer look at this fascinating and potentially lifesaving technological breakthrough.
Protecting Property Vs. Lives
In the 1990s, while writing a video surveillance story, it occurred to me how practical and efficient it would be if the fire protection industry could use real-time video images to monitor facilities for smoke and flame. In fact, when writing articles on systems integration, I began to encourage security technicians to incorporate building fire alarm systems into the integration equation so as to provide on-site as well as remote operators with real-time video confirmation of the affected area when a fire alarm occurs.
It was in 2003 when I met some folks at a trade show that claimed to have created a software package that would turn an ordinary video surveillance system into a fire detection system. As many other have, I immediately recognized the potential of this technology. But the question was, as it still is, can we tout this relatively new technology as life safety?
The answer to that question probably won’t be known for some time. But VFD can be, and often is, deployed for early warning fire protection as it relates to the preservation of property. The type of application that this technology lends itself to involves large facilities and outdoor areas, such as warehouses; manufacturing plants; airplane hangers; and large swaths of land containing trees, fields and wildlife.
Examples of Video Fire Detection
According to the report, “Forest Fire Protection by Advanced Video Detection System-Croatian Experiences,” by Darko Stipanicev, Tomislav Vuko, Damir Krstinic, Maja Štula and Ljiljana BodroÅ¾ic, “The terrestrial systems based on CCD video cameras sensitive in visible and near IR spectra are today the best and the most effective solution for realizing automatic surveillance and automatic forest fire detection systems.”
The report goes on to say that this particular flavor of VFD uses day/night cameras, making it possible to detect smoke by day using color and a flame at night using black-and-white video.
Another example is the use of video for fire detection and visual confirmation in airplane cargo holds. According to the report, “AUBE ‘01 12th Int’l Conference on Automatic Fire Detection,” published by the National Institute of Standards and Technology (NIST) of Gaithersburg, Md., ” … a new fire detection system based on digital imaging (CFMS) is introduced which creates the basis for an in-flight cockpit video surveillance system, combined with fire detection capabilities.”
Yet another example includes the use of VFD to detect fires in Australia’s Sydney Harbour Tunnel, which is said to be worth AU$554 million. Upwards of 90,000 vehicles pass through this tunnel every day, so fire detection is critical to the saving of lives.
“We cannot afford to be complacent, the fatal fire within the Melbourne City Link Tunnel in March 2007 reminds us that we must remain vigilant at all times,” Bob Allen, general manager, Sydney Harbour Tunnel, was quoted as saying.
Industry Studies Both VFD Systems
Since VFD was first introduced to the market a few years ago, the National Fire Protection Association (NFPA) has adopted language in the new 2007 NFPA 72 code that helps legitimize the use of video in the detection of real fires, such as Section A.184.108.40.206 of NFPA 72, 2007.
“Video image smoke detection (VISD) is a software-based method of smoke detection that has become practical with the advent of digital video systems. Listing agencies have begun testing VISD components for several manufacturers. VISD systems can analyze images for changes in features such as brightness, contrast, edge content, loss of detail, and motion. The detection equipment can consist of cameras producing digital or analog (converted to digital) video signals and processing unit(s) that maintain the software and interfaces to the fire alarm control unit.”
VIFD is also covered in Section A.3.3.209, NFPA 72. Here it says, “Video image flame detection (VIFD) is a software-based method of flame detection that can be implemented by a range of video image analysis techniques.” The rest reads the same as the quote above. Proponents of the technology believe it’s only a matter of time until VISD and VIFD receives the seal of approval for life-safety use from both NFPA and UL. For now, however, both VFD technologies have proven themselves worthy of consideration.
How VFD Technologies Work, Differ
Fire detection took a radical turn a few years ago with the invention of video-based fire detection (VFD). There are two primary technologies on the market, as addressed by the National Fire Protection Association (NFPA) of Quincy, Mass. They are called Video Image Smoke Detection (VISD) and Video Image Flame Detection (VIFD).
VFD in general involves the use of a special computer software through which digitized video passes. The primary difference between VISD and VIFD involves what the software is designed to look for, in this case smoke vs. flames.
In brief, video smoke detection works by the software observing a known environment, setting up a template of sorts by which real-time video is compared. When smoke is introduced into the scene, the software can detect subtle changes in contrast and image sharpness.
VIFD operates in a similar manner, only instead of monitoring the environment for subtle signs of smoke it looks for signatures common to a flaming fire, such as flicker and those colors typical of a visible fire. In regard to the former, through experimentation it has been demonstrated that a typical flame exhibits a flicker rate of about 10Hz.
Detractors of VFD often cite the potential of false alarms, but the power of this technology is actually its ability to provide visual real-time confirmation to operators, enabling them to make more intelligent, informed decisions as to whether help from local firefighters is necessary.
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