Thursday, February 16, 2012

Decade anniversary: Silo fire at Tire Recycling plant

NCNewsPress.com Article Feb 6, 2012
U.S. Fire Administration/Technical Report Series: Tire Recycling Facility Fire Nebraska City, Nebraska USFA-TR-145/January-February 2002

Excerpts from US Fire Administration report:

The Facility
The plant had been inspected by Nebraska State Fire Marshal’s Office on more than one occasion and had a history of poor housekeeping as well as a track record of poor equipment maintenance. There had previously been two fires at the site, as well as two fires at another EnTire facility, also located in Nebraska City.

The Incident
The explosion expelled chunks of rubber that were approximately two to four inches in diameter. Debris was hurled 300 to 400 feet away, damaging and destroying apparatus and equipment as well as injuring the thirteen firefighters

Investigation
The State Fire Marshal has determined that the probable cause was a faulty bearing in the stiff leg auger which carried the crumb rubber from the ground level to the top of the silos.

The bearing overheated igniting the rubber debris around the sugar base. A contributing factor was the poor housekeeping practices. No definite cause of the explosion has been identified,

Lessons Learned
Most local zoning and building codes do not adequately address facilities of this type.
Traditionally, volunteer fire departments do not become involved in local zoning issues and often lack the resources to properly preplan target hazards.

The facility in this incident was not designed for its use, nor were there adequate safe guards built into the process since the com­plex already existed and was modified to accommodate this particular process.

Fire departments should become more proactive in the permitting and zoning process and should endeavor to ensure appropriate code enforcements in facilities of this type, whenever it is possible to do so.

Sunday, February 12, 2012

How Fast Will the Fire Spread in Your Dust Layers Compared to Gunpowder (BZ 6)

A recent news account of a paper dust fire rapidly spreading a distance of 300 feet, brings to mind the importance of understanding the burning behavior of combustible dust layers.

It is time all stakeholders understand the burning behavior of their combustible dust through VDI 2263 lab test. Under elevated temperatures a layer of dust can escalate from a potentially non-spreading fire to a spreading fire. Example of BZ #'s : Salt (BZ 1) Gunpowder (BZ 6) Below are several files from BIA Report 13-97 "Combustion and explosion characteristics of dust": (BZ 1-3 No Fire Spread) in contrast to
(BZ 4-6 Fire Spread).


Index File

Information and Description File page 21/Combustion Test

Organic Products

Chemical Products

Inorganic Products

Miscellaneous Products


In thefourth file, group1_2.pdf , go to second page of material data in the last column on the right under combustibility test to find the BZ number (1-6) Note: The BZ numbers should only be used as a guideline since the dust at your facility will have unique and different characteristics of particle size, shape, moisture content, chemical composition, etc.

Another resource in locating BZ numbers is the Gestis-EX Dust database. Not all the dust samples in the database will have the BZ number. So you will have to search for several different samples in finding a BZ number to use as a guideline.

Wednesday, February 1, 2012

Revise Combustible Dust National Emphasis Program (NEP): Poll




Combustible dust related fires and explosions are occurring throughout the manufacturing and non-manufacturing sectors that are not specifically recognized in Appendix D-1 & D-2 of the OSHA Combustible Dust National Emphasis Program (NEP). 
http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=directives&p_id=3830

Recently a CSB recommendation in the Hoeganaes Case Study instructed OSHA to revise the Combustible Dust National Emphasis Program (NEP) to add industry codes for facilities that generate metal dusts (e.g., North American Industrial Classification System, NAICS, code 331111 Iron and Steel Mills, and other applicable codes not currently listed)..

What about the dozens of other NAICS having a history of combustible dust related fires and explosions that are not recognized in the ComDust NEP?

 

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