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Spark Detection System Spark Detection System
Fire & Explosions
Every year, people are injured and even killed as a result of industrial fires and dust explosions. Process industries worldwide lose millions per year in damages and production interruptions due to fire or dust explosions.
As opposed to taking action after the event of a fire or dust explosion, it is also possible to implement proactive measures to prevent a fire or explosion to occur in the first place. Intelligent process design and proper housekeeping are examples of vital measures. The installation of a Firefly spark detection system is another.
The principle of spark detection
A spark detection system consists of a detector that identifies dangerous particles (ignition sources) in process flows. Once a particle is detected, it is within milliseconds automatically extinguished before it can create a fire or a dust explosion. The detection and extinguishing functionalities are controlled by a control unit. This proactive way of eliminating ignition sources is why Firefly spark detection systems are called ‘preventive systems’.
The installation of a Firefly spark detection system can save the industry from costly fires and dust explosions. By combining unique and patented technology with 40 years of experience in the process industry, Firefly offers premium safety solutions that minimize false alarms and keep the industries in production.
Scientific research shows at which temperatures and energy levels different combustible materials can ignite. To be considered adequate, a spark detection system should detect ignition sources at these levels.
Ignition temperatures & energies
Different materials have different minimum ignition temperatures (MIT) and different minimum ignition energies (MIE). Only when both the MIT and MIE levels are met or exceeded, ignition can take place. The expression ‘spark detection systems’ may be misleading; one would believe that sparks are the only cause of industrial fires and explosions. An impact spark can have a very high temperature; it can very well be 1000°C. But, an impact spark normally contains a very low amount of energy and is therefore not likely to cause an ignition. In many cases, a piece of overheated material from the process most often contains more energy. This overheated material is therefore much more likely to cause an ignition compared to an impact spark.
Hot black particles
A hot particle will emit light, visible to the human eye when it has a temperature of about 700°C or more*. All particles below this temperature are perceived by the human eye as ‘black’ particles. As previously shown, most combustible materials can ignite at much lower temperatures than 700°C. Note that many fire problems in industrial processes are friction-related, i.e. initially creating hot black particles and not visible sparks.
All Firefly detectors are insensitive to daylight. Besides detecting down to the relevant temperature and energy levels, avoiding false alarms is a crucial aspect in the detection functionality of a spark detection system. Because each daylight detection results in the injection of unnecessary water into the process, secondary losses and often also costly production downtime are the unwanted results.
By detecting down to the relevant minimum ignition temperature and energy for different combustible material, and being insensitive to daylight, a Firefly spark detection system offers a premium detection functionality which is unrivalled on the market.
Why Firefly - Detection
Firefly’s TrueDetect technology™ enables detection down to the right ignition temperatures and energy levels for different materials without being sensitive to daylight. A Firefly True IR detector is based on lead sulphide cells (PbS) and is therefore insensitive to daylight. Conventional spark detectors are based on silicone photodiodes (Si) and will therefore detect visible light and near infrared radiation (i.e. temperatures from about 650°C or higher).
As the only supplier in the world, Firefly equips all its True IR detectors with the patented Multi-checkpoint technology™ to ensure detection quickness and reliability. Using a derivative measuring principle, Firefly True IR detectors can detect dangerous particles at transport speeds up to 50m/sec.
To consider when choosing suitable detector type:
- determine the minimum ignition temperature (MIT) and minimum ignition energy (MIE) of the processed material.
- choose the detection technology that will meet the MIT and MIE of that material.
- analyze possible detection disturbance sources and make sure that the chosen detector will not cause false triggering
Process industries generally handle large material flows; from hundreds of kilos up to hundreds of tons per hour. High flows of compact material demand a powerful extinguishing which is able to fully penetrate these flows.
Water is the most common method of extinguishing. However, dangerous particles can also be eliminated by means of mechanical diversion, isolation, steam or gas in applications where water is not suitable for use in the process.
If you use water extinguishing to protect your process from fires and dust explosions:
- require extinguishing from different directions in order to secure full coverage of the entire cross-section of a duct or chute.
- extinguishing needs to be powerful enough to penetrate also large and compact material flows.
- extinguishing needs to react within milliseconds after detection.
Why Firefly – Water Extinguishing
Firefly provides high-speed and powerful full-cone extinguishing with a unique nozzle design and placement from different directions aimed to penetrate and cover the entire material flow inside a pneumatic conveying system or chute.
Conventional extinguishing systems use hollow-cone spray nozzles with relatively small water droplets, often installed only from one direction. Consequently, conventional extinguishing provides less ability to penetrate the entire material flow and can leave uncovered areas inside a pneumatic conveying system or chute.
Other extinguishing methods
Firefly offers a wide variety of methods for extinguishing, isolation or diversion of ignition sources for processes where the use of water is not suitable.
Firefly’s ultra-fast isolation and diverter valves are known for their high quality and superb functionality and are available in many types and sizes. CO2 gas is often used in combination with isolation valves to inert the isolated process volume.
Also other extinguishing methods such as inert gas, foam, steam or other chemical agents can be included in Firefly’s system solutions.