Video Smoke Detectors
In the life safety area, video analytics capture images and use an algorithm to compare the images to a database of smoke and fire patterns. Typically these tools are assessing changes in brightness, contrast, motion, and color. The use of video in this manner has several advantages. The cameras may reduce or eliminate the need for traditional smoke detectors. Also, you can use the video smoke detector in spaces where a traditional smoke detector may not work, such as vehicle tunnels, high ceilings or in locations where the detection device may be exposed to outdoor elements. The first recognition of video images used for fire and smoke detection was in the 2007 edi-
Figure 19.3 tion of NFPA 72. (As always, their use should be discussed and approved by the local authority having jurisdiction (AHJ), generally the Fire Marshall.)
With typical smoke detectors the smoke from a fire has to move to the smoke detector causing transport delay, essentially wasting time to trigger the detector. Video smoke detectors have no such delay and therefore are quicker resulting in less damage and threat to life. When a fire occurs, minimizing detection latency is crucial to reduce damage and save lives.
While the main purpose of video cameras is physical security, analytic software allows for more enhanced applications. In the future we can expect video cameras to take on the role of building sensors, not only in calculating occupancy, but, sensing other characteristics such as light levels or even thermal comfort. Video cameras are the Swiss Army Knife (probably the most famous name in multi-tools) of building sensors.