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