Advances Spark New Age of Fire Safety
While the controlled use of fire predates written history, it has taken humans until modern times to nearly master its deadly capabilities. Thankfully today, an array of detection technologies has drastically reduced the threat to lives and property as the result of fire, smoke and gases. Get up to speed on the latest fire safety innovations.
Perhaps no other technology in the past 150 years has contributed more to fire safety than early warning smoke detection systems. Data collected during the past 40 years alone estimates 90,000 lives have been saved by smoke detection and fire protection technologies. In addition, countless other potential tragedies may have been averted by early warning and intervention.
From rudimentary heat detectors invented in the late 1800s to sophisticated and integrated electronic systems in place today, smoke detection has been a significant scientific achievement. Like many aspects of modern life that we take for granted, progress has been the result of the convergence of need and opportunity.
Recent studies reveal the odds of dying in a house fire are reduced 50% by having a working smoke alarm/detector installed. In commercial buildings, even in the presence of sprinkler systems, the benefits of smoke detection are significant. Sprinkler systems, by design, provide a localized response as heat (typically above 135° F) triggers the sprinkler directly where the fire is burning. Smoke detection systems integrated across commercial buildings quickly warn occupants of a potential danger before it spreads.
Clearly the best life-safety solution is to provide a combination of early warning smoke detection and fire sprinkler systems. Let’s take a look at the impressive variety of fire/life-safety detection technologies and devices currently available to help installing contractors best protect their clients’ persons and properties.
Advances Enable Smarter Detection
Today the focus is on integration of “smart” (multicriteria fire detection) technologies that increase value, simplicity and reliability. For example, one area of development involves advanced signal analysis via software that converts sensor signals into a mathematical formula. In real-time, the software dynamically compares signal data to sophisticated algorithms that differentiate between a fire emergency and harmless smoke (e.g., from a welder, steam, dust).
In special applications such as data and telecommunication centers, ultra-sensitive air sampling smoke detection systems continuously monitor the air and apply a staged alarm sequence to determine if, when and how a response is needed. For example, an active monitoring system may combine multiple air-intake ports to provide more immediate notification and increased efficiency within areas of high airflows.
One detector can cover up to 20,000 square feet as compared to passive detectors that generally cover about 900 square feet. Additionally, spot detector technology has evolved to include the capability to provide high sensitivity capabilities for Very Early Warning Fire Detection (VEWFD) suitable for the protection of a telecommunication facility, data center and high value areas.
Multicriteria fire detectors are the emerging technology in the 21st century. Technology today provides for two or more different fire sensors (e.g., smoke, heat, CO, ion, etc.) in a single detector that will process the signals with algorithms to determine alarm or monitoring status. Multicriteria detectors can sense danger more quickly, avoid nuisance alarms and provide valuable information for emergency responders. Combined with newer panels and control systems, they can also improve reliability and reduce maintenance costs.
As smoke detection advancements continue, it is useful to understand the current state of detection technologies to better understand the landscape and make informed choices when specifying system elements, and to mitigate risk within the context of the facility and its intended purpose.
Detectors using ionization technology are based on an “ionization chamber” that includes a small radioactive source and a positively and negatively charged electrical circuit. The radiation “ionizes” the air in the chamber by removing an electron and thus maximizes electrical flow across the circuit. Any smoke particles entering the chamber neutralize the air, which reduces the current flowing across the electrical circuit and triggers the alarm.
Generally speaking, ionization technology is low cost, and most common in home detection units and basic commercial systems. Ionization smoke detectors are particularly effective for quick response to fast burning fires (which may produce less smoke than smoldering fires), but these kinds of units are also more prone to false alarms (e.g., from cooking, toaster, cleaning aerosols etc.)
For the most part, ionization sensors are used in residential systems or in some multicriteria detectors. In the latter, combining ionization with other technologies helps detect different smoke signatures more quickly, while also avoiding false alarms.
Optical Sheds Light on Sensing
In the most common smoke detector units, photoelectric cells register changes in light intensity as minute smoke particles enter the detector. These units often have the receiver sensor at a 90° angle to the photo beam — smoke particles “scatter” the light beam and cause rays to hit the receiver, which triggers the alarm. Forward scatter detectors typically are more accurate sensing light smoke particles, while backscatter technology better distinguishes lighter and darker particles.
More advanced optical systems operate on a similar principle, but may involve laser beams or more precise and accurate light sources. Light meters that measure ultraviolet rays are also used in “flame detectors” that help identify when a fire is present in manufacturing environments or other situations that are normally smoky or dusty.
Photoelectric sensors have long been popular in home smoke detectors and commercial units because they are more accurate at detecting smoldering fires than ionization. These types of detectors are relatively low cost and have proven reliable across a long period of time.
The upper-end optical systems, such as laser sensors, also work well in sophisticated aspirating smoke detection systems that actively monitor air samples and channel them to a centralized detection unit.
Multicriteria units are often integrated into smart monitoring systems. For example, one manufacturer has developed a dual optical multicriteria system that combines both forward and backward light scattering sensors with thermal detection to provide very early warning to both smoldering and flaming fires.
Gas Units Warn of Invisible Dangers
Gas detectors, which are in common use today, operate on a similar principle as ionization detection. Electrochemical or catalytic circuits are programmed to measure changes in current brought on by the presence of gases with
specific molecular structure. Gas detection is becoming more common and sophisticated to address air quality and safety issues. For example, 35 states have legislation mandating installation of carbon monoxide (CO) detectors for life safety.
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