CTA Report, Draft 1, ISP Review - US Chemical Safety and Hazard ...

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C.1 Findings 1. The temperature controller memory was erased due to loss of power in the facility and failure of the backup battery. 2. The natural gas regulator for the oven 405 burner (Eclipse) had a measured output pressure of 11 inches of water column. The burner’s fixed gas butterfly valve was set at 80 to 90 percent closed to reduce gas input. Recorded burner flow rates would give a heat rate of approximately 210,000 British thermal units per hour (Btu/hr). 3. All timers in the burner control panel were found at their minimum settings. 4. The audible alarm mounted to the cabinet door of the burner control box was not connected. 5. The high gas pressure cutoff switch was set at 5 psi. 6. The normally open solenoid gas bleed valve had a 0.7 liter per minute (L/min) leak-through rate when energized. 7. The electronics for the oil pump control box were mounted on a plywood base plate. Several knockouts and feed troughs were not adequately covered or strain-relieved. The intended dustproof National Electrical Manufacturers Association (NEMA) ratings of the burner control boxes would not be met under observed conditions. 8. The burner 405 oil pump was found to have no abnormalities beyond damage that can be attributed to excessive external heat. 9. No significant external gas leaks (into the building) were found. 10. All components found on the subject controller were consistent with a Type I-535, manufactured between 1990 and 1998, except the display assembly, which was found to be a design from the Type 112
II controllers, only manufactured after January 1, 1998. The Type II display assembly was re-fitted into a Type I harness and Type I operator fronts. C.2 Conclusions The Crane-Powers temperature controller, tested in phase 4, was reported to have lost all data due to loss of power and backup battery failure. It is not clear why the battery failed. The battery draws down whenever the controller is not powered and is not rechargeable. The Moore Industries controller technician estimated that the average life of the controller’s battery was 5 years. If the date code on the controller display harness were consistent with controller and battery installation, then a battery with a life of 5 years likely would have expired prior to 2002. In general, there are electrical incompatibilities between Type I and Type II assemblies, particularly the option board, the power supply board, and the microcontroller board. By design, these sub-components must be replaced in-kind in order for the controller to operate correctly. However, for the display assembly, electrical designs are compatible, in that the user may cross-populate between types to yield a workable solution. Testing during phase 4 determined that interchangeability between platforms is feasible and that the CTA temperature controller configuration did not present a significant failure mode with respect to controller integrity. There were indications that the burner control box had been open or not properly sealed during operations and was open at the time of the explosion. Plant debris (i.e., fiberglass, dust, oily material) was present in the interior of the burner control panel and on the inside of the temperature controller, which was intended to be mounted within a NEMA-rated equivalent protected environment. The contamination may have contributed to the reported controller problems; there was some improvement in operation after the internal circuit boards were cleaned during phase 4 testing. 113
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KEY ISSUES: U.S. CHEMICAL S AFETY A
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5.1.2 Line 405 Oven Temperature Con
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9.1 FM Global Guidelines...........
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Figures 1 Simplified Layout of CTA
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ACC American Chemistry Council Acro
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Executive Summary A February 20, 20
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1.0 Introduction At approximately 7
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2.0 Key Findings 1. Combustible phe
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3.0 Facility Description 3.1 CTA Ac
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eams. Nonload-bearing masonry block
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Thirteen-foot-high freestanding enc
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4.0 Process Description The product
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4.1.2 Mat-former and Baghouse In th
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Circulating fans and dampers direct
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• Manually striking baghouse bags
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5.0 Incident Description 5.1 Pre-In
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• The line was one week past due
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forklift with a semi-enclosed cab d
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panels and lights down inside the b
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occurred in the southeast corner of
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5.3.3 Firefighting Activities 5.3.3
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5.4 Incident Aftermath The CTA inci
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6.0 Understanding Combustible Dust
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As depicted in Figure 11 (Eckhoff,
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Figure 12. Mechanism for a dust fir
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7.0 Reconstructive Analysis To dete
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urned clean but otherwise intact an
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7.1.2 Other Possible Initiating Eve
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Table 3 Borden Chemical Black Pheno
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7.3 Line 405 Equipment Testing CSB
Page 61 and 62: determine if those products are haz
Page 63 and 64: that the phenolic resin could explo
Page 65 and 66: A 1998 internal Borden Chemical mem
Page 67 and 68: • Characterize new and existing p
Page 69 and 70: CTA that phenolic resins, when susp
Page 71 and 72: CTA department supervisors were res
Page 73 and 74: 8.5 Work Practices 8.5.1 Production
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Page 77 and 78: 8.7 Incident Investigations The inc
Page 79 and 80: • Excessive accumulations of comb
Page 81 and 82: Data Sheet 6-9 also states: Clean o
Page 83 and 84: Table 5 Insurance Company Dust Issu
Page 85 and 86: standards (Appendix D). Kentucky OS
Page 87 and 88: 10.2.2 Division of Building Codes E
Page 89 and 90: 11.0 Combustible Dust Hazard Study
Page 91 and 92: 4. The Borden Chemical product stew
Page 93 and 94: 13.0 Recommendations CSB developed
Page 95 and 96: Kentucky Office of Occupational Saf
Page 97 and 98: BY THE U.S. Chemical Safety and Haz
Page 99 and 100: Lawson, Robert G., 1984. Beverly Hi
Page 101 and 102: APPENDIX A: Fire and Explosion Dama
Page 103 and 104: APPENDIX B: Laboratory Testing of P
Page 105 and 106: B.2 Minimum Explosible Concentratio
Page 107 and 108: B.4 Propagating Brush Discharge Ign
Page 109 and 110: Material Corona Charge Voltage (kV)
Page 111: APPENDIX C: Equipment Testing Line
Page 115 and 116: Therefore, at any given time, it wa
Page 117 and 118: APPENDIX D: NFPA Guidelines In prom
Page 119 and 120: D.2 Other Pertinent NFPA Codes D.2.
Page 121 and 122: APPENDIX E: HMIS Rating System The
Page 123 and 124: APPENDIX F: Simplified Organization
Page 125 and 126: Subtree A Second dust explosion abo
Page 127: Subtree C Most CTA personnel had a
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