| In any type of production facility, fire control | | | | lamps indicated a flow of sparks, the trouble |
| encompasses a wide range of equipment or | | | | message is now displayed in clear text. Important |
| systems from building sprinklers to plant site fire | | | | functions and all alarms are displayed clearly. The |
| departments. A spark detection/extinguishing | | | | buttons on the keypad light up and provide visual |
| system must be thought of as part of a plant's | | | | information.Integrated MemoryThousands of |
| overall security and safety network. Just as a | | | | events are stored so that important information |
| residential alarm system provides protection to a | | | | is not lost. This enables analysis of alarms at any |
| homeowner, a spark detection system provides | | | | time: |
| preventive protection against potential loss of | | | | |
| human life, production facilities, equipment and | | | | When exactly did the spark stream happen? |
| costly downtime.Where do Spark Streams | | | | How heavy was the spark stream? |
| appear?Spark streams in dust collection systems | | | | How long did the extinguishment action last? |
| are a very common danger. They are not easily | | | | Where exactly did the spark stream appear? |
| detected and this means that they may exist but | | | | When was the system out of action? |
| are not known! Consequently, attention is paid to | | | | When and where did troubles appear? |
| a spark stream only when it is too late, namely | | | | |
| when there has been an explosion or a fire.When | | | | The answers to these questions can be found in |
| working with industrial machinery, sparks are | | | | the memory of the control console and the |
| created very quickly. A blunt tool, a damaged | | | | danger spots can be identified very quickly. The |
| bearing in the fan, an overheated motor or | | | | display field not only shows the alarm itself, but |
| foreign body within the material can be the | | | | also informs about the measures that have been |
| cause.Sparks are a constant danger in those | | | | taken. The memory content can be printed out at |
| factories where combustible materials are being | | | | any time to an external or internal |
| worked, exhausted, transported, filtered or | | | | printer.Automatic Function Checks To ensure |
| dried.The damage statistics provided by the | | | | cables are functioning correctly, they are |
| insurance companies point out that filters, dust | | | | constantly checked for open and short circuit |
| collection bins, silos and even complete production | | | | conditions. In addition, spark sensor function tests |
| lines are the areas of a plant at greatest risk. | | | | are performed regularly and automatically. |
| Foreign bodies in the conveyed material, defective | | | | Extinguishing device function tests can be |
| parts of the production machinery, friction | | | | performed manually from the control console.The |
| processes as well as electrical sparks are all | | | | Spark DetectorThe most important component |
| identified as fire generating. Here are the main | | | | of a spark detection and extinguishment system |
| danger areas known: | | | | is the spark detector. To suit the different and |
| | | | often very severe applications, three different |
| Fiber and Particle Board Industry: The fiber and | | | | types of sensors are used. All three sensor types |
| particle board processing as well as the further | | | | have highly sensitive electronics which detect |
| processing of the panels by sawing and sanding | | | | even the smallest of glowing particles.Spark |
| Wood-Working Factories: Working of materials | | | | Detector FM 1/8The FM 1/8 detector features |
| by means of saws, planers, mortisers, hoggers, | | | | reliable function even in very dense material flow |
| sanders and other wood working machines | | | | or when a dust layer covers the optical element. |
| Chemical Industry: Pneumatic conveyors of dusts | | | | It can be used at material temperatures up to |
| and powders | | | | 149°F (65°C), which corresponds to a |
| Foodstuff Industry: e.g. Coffee roasting, tobacco | | | | temperature range of extraction systems for |
| processing and pneumatic conveying of powders | | | | woodworking machines like saws, planers, sanding |
| | | | machines, etc.Spark Detector FM 3/8The FM 3/8 |
| Why is it so Dangerous?The spark itself is not | | | | detector is used in applications with operating |
| dangerous. Here's why: For the creation of fires | | | | temperatures above 149°F (65°C) as |
| or explosions there must be three elements that | | | | can appear in drying processes, for example. |
| are combined simultaneously: a combustible | | | | Spark radiation is carried through fiber optic cables |
| material, oxygen and an ignition source. Removal | | | | to the detector.Daylight Spark Detector DLD 1 |
| of one of the elements will prevent a fire or | | | | 8For the most reliable detection of glowing or hot |
| explosion.In today's production plants, we have to | | | | particles, no ambient light can be present at the |
| cope with all elements that can lead to fire | | | | sensor location. However, where an absolute dark |
| damage or cause an explosion. Extraction | | | | surrounding cannot be guaranteed, sensors that |
| systems and pneumatic conveyors increase the | | | | aren't sensitive to daylight or ambient light are |
| danger of fire. Once sparks and glowing embers | | | | used. These sensors operate only in the infrared |
| are created, the pneumatic extraction system | | | | spectrum of light so they can be installed at open |
| conveys this danger very quickly to other | | | | transfer points or on conveyor belts.Thermo |
| subsequent areas of the plant. The danger is | | | | Detector TM 1/8The thermo sensor TM 1/8 is |
| when two of the three elements necessary for | | | | used for the additional inspection of large areas, |
| the creation of fires and explosions are | | | | like filter and silo systems. Its task is to monitor |
| transported, namely: air and ignition sources | | | | these areas for self-ignition of the material being |
| (sparks).When this conveyed danger meets | | | | conveyed or stored.The Extinguishing |
| combustible materials (filter cloth, deposited and | | | | DeviceWater is the best extinguishing agent. Its |
| combustible dust in a separator or silo) it becomes | | | | excellent extinguishing efficiency mainly results |
| more and more likely that a reaction will | | | | from the high ability of heat absorption. For this |
| happen.Environmental protection measures | | | | reason it has a strong cooling effect that |
| regarding dust emissions and tightened regulations | | | | prevents re-ignition of the combustible |
| for air pollution led to an increased use of filter | | | | materials.To obtain an optimal extinguishing |
| systems, but the danger of dust explosions has | | | | efficiency, the area covered by the water must |
| not been reduced. In the process of drying, the | | | | be kept as big as possible. This is accomplished by |
| dryer capacities have been steadily increased so | | | | a fine atomization of the water. Atomization is |
| that prevention of fires in these systems has | | | | achieved through a special nozzle and sufficient |
| become more important than ever.What happens | | | | operating water pressure. With high atomization, |
| after a filter fire? Environmental regulations | | | | the amount of extinguishing water can be |
| prohibit plant operation without the filter system. | | | | minimized so that filter elements are not damaged |
| The plant will not only have the cost of repairing | | | | by an excessive amount of water. This allows |
| the damaged filter system caused by fire but also | | | | production to continue while extinguishing takes |
| absorb the extremely high loss of a production | | | | place.The operating pressure of the extinguishing |
| shutdown.According to individual reports, these | | | | device should be at least 60 PSI at a flow rate of |
| production losses can exceed the damage costs | | | | 24 GPM per nozzle. If this pressure is not |
| many times over.The risk of fire can be | | | | available, a pressure-increasing unit must be used. |
| efficiently reduced or eliminated by means of | | | | Because extinguishing nozzles are spring loaded |
| modern spark detection and extinguishment | | | | and flush-mounted, they are contamination-free |
| systems.Returned air to the plant also requires | | | | and do not obstruct the material flow.Not all |
| spark detection and extinguishment systems. Due | | | | extraction ducts of the plant are located inside |
| to the high amount of material now collected in | | | | the production building. Sometimes the |
| the dust filter systems, in certain circumstances | | | | extinguishing devices are required to be installed |
| clean air is allowed to be returned to the | | | | outside. Heat tape and insulating material is used |
| production buildings. Enormous savings in heating | | | | to protect water pipes and extinguishing devices |
| energy are achieved in this way. A filter fire, | | | | from freezing in areas exposed to frost. Special |
| however, could quickly be transferred to the | | | | insulating bags are available for the extinguishing |
| production area with devastating consequences.To | | | | devices.Alternatives to Extinguishing MeansIn |
| protect such a system, all extraction ducts as well | | | | some production and processing systems, water |
| as the conveying duct to the material storage | | | | cannot be used as an extinguishing means |
| should be equipped with spark detection and | | | | because it would have too much influence on the |
| extinguishment systems.How can you take | | | | subsequent process. This is particularly true for |
| Preventive Measures?Protection can be achieved | | | | the food industry where extremely high accuracy |
| by installing a modern spark detection and | | | | in respect to the material's moisture must be |
| extinguishment system. The sensors detect | | | | observed. There are also other industries where |
| sparks and glowing embers immediately after | | | | water is not allowed as an extinguishing agent. |
| their creation. Upon detection and evaluation, | | | | There are alternatives: Diversion gates, shut-off |
| countermeasures are induced immediately in order | | | | gates, fire traps and even the actuation of a C02 |
| to eliminate the causes of a fire or an | | | | or other inert gas system.Diversion Gates, |
| explosion.Let's compare fire extinguishment | | | | Shut-off Gates, Fire Traps.In these industries, |
| systems with spark detection and extinguishment | | | | diversion gates to abort the material flow or |
| systems. Fire extinguishing systems combat fire | | | | shut-off gates and fire traps to stop the material |
| after it has come to life, consuming material and | | | | flow are used. When the spark sensor detects a |
| air thus producing smoke and damage. A spark | | | | spark, or when the preset spark threshold is |
| detection and extinguishment system eliminates | | | | exceeded, the installed device is activated from |
| one of the three elements (the ignition source) | | | | the control console.CO2 ExtinguishmentIf parts of |
| before it becomes a fire. In this way there is no | | | | the plant, complete machines or sensitive filter |
| fire, no smoke, and no damage.Spark detection | | | | systems are to be extinguished, a C02 system |
| and extinguishment systems are able to detect | | | | can be activated by a spark detection system. |
| even the smallest of sparks or hot particles in | | | | For this application, spark sensors monitor the |
| extraction ducts, drop chutes or mechanical | | | | ducts leading to these areas. Upon detection of |
| conveyors, and to instantly trigger | | | | sparks, an alarm message is transferred to the |
| countermeasures. Countermeasures can be: | | | | CO2 system through voltage-free relays of the |
| activation of an extinguishing system, diverting the | | | | control console. The corresponding parts of the |
| transport path or interrupting the production. All | | | | system are simultaneously shut-off by activating |
| these measures are taken within a split | | | | shut-off gates so that the incoming CO2 can now |
| second.Detection of the ignition source is made by | | | | flood the contained area.Central Visualization |
| means of spark sensors recognizing the infrared | | | | SoftwareEvents recorded by several consoles |
| radiation of sparks and glowing particles. These | | | | that are installed in different areas of the plant |
| sensitive spark sensors are even capable of | | | | are accessible through the visualization software. |
| detecting sparks through layers of dust or | | | | Such an application offers many advantages: |
| through the conveyed dense material flow. The | | | | Central actuation and processing of all spark |
| sensors give alarm signals to the control console, | | | | alarms on one monitor is possible. The central |
| which processes the signals and activates the | | | | acquisition of all events provides the operator with |
| appropriate countermeasures automatically. | | | | meaningful and comparable data. The remote |
| Normally an extinguishing device is triggered, which | | | | control of the individual spark extinguishing |
| is installed downstream from the spark detectors. | | | | systems make it possible to react rapidly on each |
| This device releases a mist of water in the duct | | | | alarm event and allows time and cost savings and |
| section where the sparks are transported. When | | | | shorter production interruptions.Spark Detection |
| no additional sparks are detected, the | | | | and Extinguishing Systems Insurance Premium |
| extinguishment spray is automatically stopped. | | | | RatesFire insurance companies have |
| While the extinguishment takes place, the | | | | acknowledged the minimized risk when automatic |
| production process can continue unless otherwise | | | | spark detection and extinguishment systems are |
| desired. Due to this special operation principle, | | | | installed, and may grant discounts on insurance |
| spark detection and extinguishment systems are | | | | premiums. Precondition for achieving discounts on |
| classified differently than sprinkler systems, deluge | | | | premium rates is the use of an extinguishment |
| systems, or even explosion suppression | | | | system that is approved by a commercial and |
| systems.The Control ConsoleThe centerpiece of a | | | | industrial property insurance and risk management |
| spark extinguishing system is the control | | | | organization. Factory Mutual is one such |
| console.All signals given by the spark sensors | | | | organization and the only North American |
| installed in different plant areas are being | | | | organization to test spark detection and |
| accumulated and processed by a microprocessor. | | | | extinguishment systems. Factory Mutual requires |
| The extinguishing devices of the affected areas | | | | stringent manufacturing standards and technical |
| are activated without any delay.A practical fire | | | | reliability that not only applies to the system, but |
| protection concept also considers the demand for | | | | also to the planning, installation and after-sales |
| an almost uninterrupted production. The use of | | | | service.ConclusionSpark detection and extinguishing |
| microprocessor technique including the | | | | systems are among the most efficient fire |
| corresponding software results in new possibilities | | | | prevention systems, which is a result of their |
| to react on sparks. Integrated counters and time | | | | highly developed technique and reliability. The use |
| recording systems allow an exact assessment of | | | | of these systems for various applications is even |
| the spark stream. A graded use of the existing | | | | prescribed by Factory Mutual. All these factors |
| countermeasures is then possible.For example, | | | | lead to considerable investment reductions and |
| single sparks are only extinguished, but for heavy | | | | improved safety for your plant, people and |
| flow of sparks or when single ignition sources are | | | | production.Author |
| detected over a longer period, further measures | | | | Bob Barnum, Vice President of Sales for GreCon, |
| like machine shut down of the affected plant | | | | Inc. Bob has over 30 years of experience with |
| sections have to be taken. Diversion of the | | | | pneumatic and mechanical conveying. GreCon is an |
| material transport is also possible using fast-acting | | | | ISO 9001 and Factory Mutual Approved |
| abort gates.The microelectronics has many other | | | | manufacture of spark detection and |
| advantages.Ease of OperationWhere once little | | | | extinguishment systems. |