Reason Magazine 2014 Quartal 2 Seite 30

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Another common area where combusti ble materials can be found in a semiconduc tor facility is the exhaust ductwork Many of the waste vapors and gases liberated from wafer production are corrosive limiting the materials that can be used in the construction of the exhaust system Combustible ductwork presents an enormous fire hazard in a semiconductor fabrication facility as there are often miles of ductwork travelling through the facility that can provide a path for fire to spread It is entirely possible that the combustible smoke and other fumes will continue to be exhausted from the cleanroom reducing the potential for contamination Another option for protecting combus tible ductwork for extremely corrosive envi ronments is to provide corrosion resistant sprinkler nozzles as outlined in Data Sheet 7 78 Industrial Exhaust Systems This pro tection utilizes a technology developed and patented by FM Global utilizing the above mentioned coated sprinkler nozzles with a linear heat detection system triggering a deluge protection system and the compo nents of this protection system have been tested and shown to be able to withstand the extremely corrosive environments found within these ducts There are commercially available FM Approved corrosion resistant nozzles suitable for this use Selecting noncombustible ductwork or using Approval Standard 4922 for a new exhaust system is a great property conser vation measure but in an existing fabrica tion facility replacing the existing ductwork may not be possible in the short term In these instances Data Sheet 7 7 recommends that a companywide policy be developed to replace combustible ductwork with either noncombustible or Approval Standard 4922 ductwork as the opportunity arises perhaps during retooling or a redesign of a section of the cleanroom Until such time as combustible ductwork can be replaced Data Sheet 7 7 provides guidance on how to protect the combus tible ductwork to prevent the spread of fire throughout the fabrication facility guarding against the potential for a large and destruc tive loss like the one at the SK Hynix plant For more information on construction material related fire hazards or other hazards associated with a semiconductor fabrication facility please refer to Data Sheet 7 7 which can be found at fmglobal com datasheets ductwork was the mechanism for fire spread in the SK Hynix fire In order to avoid the potential of a multimillion dollar loss non combustible ductwork such as stainless steel is an ideal choice or ductwork that is manufactured to Approval Standard 4922 Fume Exhaust Ducts or Fume and Smoke Exhaust Ducts The key difference between an Approval Standard 4922 cleanroom duct and the other Approval Standard 4922 ducts listed in the Approval Guide is that the ducts rated for cleanroom use will maintain their structural integrity during a fire so that TOP Snapshot of a plastic wet bench free burn test conducted by FM Global BOTTOM As seen here combustible ductwork presents a dangerous fire hazard 30 Reason ISSUE 2 2014 theSCIENCE