Photo Credit: U.S. Chemical Safety Board -“Large hole (approximately 3 x 7 inches) in a corroded section of piping that carried hydrogen and ran through the trench.”
Incorrect labeling the third Hoeganaes incident on MAY 27, 2011 as a combustible dust flash fire resulting in three fatalities. “…not just one, not just two, but three — three! — combustible dust flash fires.” They killed a total of five workers and injured three others.In contrast, according to the CSB Hoeganaes Case Study, the third incident was a hydrogen vapor cloud explosion (VCE) where hydrogen was ignited following a leakage from a corroded section of piping conveying hydrogen. http://www.csb.gov/assets/document/CSB_Case_Study_Hoeganaes_Feb3_300-1.pdf (page 6 .pdf)
There were no reported thermal burns of employees from combustible dust flash fires in this incident. “Two mechanics near the forklift were transported to a local hospital where they were treated for smoke inhalation and released shortly thereafter.”
“Witnesses saw burning dust raining down from above. However, the witness statements as well as the physical evidence leave no doubt that combustible iron dust was also involved in the aftermath of the explosion. Examining the scene following the incident, CSB investigators observed splattering of burned iron dust.” http://www.csb.gov/assets/news/document/Final_Statement_6_3_2011.pdf (page 2-3 .pdf)
Since when does burning dust raining down from above resulting in splattering of burned iron dust on the deck constitute a combustible dust flash fire? A ComDust flash fire requires a minimum explosive concentration (MEC). Burning dust raining down is not a flash fire.
Tunnel vision ignoring other explosive atmospheres in conjunction with accident investigations determining root and contributing cause regarding mechanical integrity in close proximity to combustible dust is not the solution in comprehensively addressing best practices from lessons-learned.
“Powdered metals plant in Gallatin Tennessee had not just one, not just two, but three — three! — combustible dust flash fires. They killed a total of five workers and injured three others.”
The “company’s lack of adherence to rigorous dust control standards was the primary cause of the incidents due to large dust accumulations throughout the facility. ” http://www.csb.gov/assets/news/document/ICC_Speech_10_22_2012.pdf (page 3 .pdf)
So lack of adherence to rigorous dust control standards was the primary cause of the corroded hydrogen piping resulting in the catastrophic hydrogen vapor cloud explosion (VCE) with three fatalities? What about adherence to best industry practices referencing ASME B31.12 Hydrogen Piping and Pipelines, NFPA 55 Compressed Gases and Cryogenic Fluids, CGA G-5.4 Standard for Hydrogen Piping Systems at User Locations and NFPA 2 Hydrogen Technologies Code in preventing future catastrophic hydrogen vapor cloud explosions?
Excellent resource from the EUROPEAN INDUSTRIAL GASES ASSOCIATION. “Scope of this document is for metallic transmission and distribution piping systems carrying pure hydrogen and hydrogen mixtures.” Must read section on corrosion protection for underground pipelines. Did the Hoeganaes hydrogen pipeline have sufficient corrosion protection? http://h2bestpractices.org/docs/Doc121_04%20H2TransportationPipelines.pdf
Solely referring to the primary cause of the hydrogen vapor cloud explosion as large dust accumulations throughout the facility could possibly overlook more pertinent root and contributing causes such as insufficient corrosion protection. Are global stakeholders aware their underground hydrogen piping is at potential risk?
Post Contributor: John Astad – The Combustible Dust Policy Institute – Combustible Dust Blog: http://dustexplosions.blogspot.com/
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