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WARNING - this video shows the ignition of the dust cloud and people within the dust cloud on fire and trying to escape. The sights and sounds of this video ARE VERY GRAPHIC in nature, but shows the hazards of Corn Starch and its ease to ignite.
Corn Starch has one of the lowest MIE's in the Combustible Dust family. We do not yet know the ignition source, but a high wattage concert light bulb or a lit cigarette would be enough to ignite this cloud of corn starch.
As you watch this video, remember the five (5) things that have to be present for a COM DUST incident:
The U.S. Chemical Safety Board (CSB) completed a study of combustible dust hazards in late 2006, which identified 281 combustible dust incidents between 1980 and 2005 that killed 119 workers and injured another 718. Based on these findings, the CSB recommended OSHA pursue a rulemaking on this issue. OSHA has previously addressed aspects of this risk. For example, on July 31, 2005, OSHA published the Safety and Health Information Bulletin, ‘‘Combustible Dust in Industry: Preventing and Mitigating the Effects of Fire and Explosions.’’ Additionally, OSHA implemented a Combustible Dust National Emphasis Program (NEP) on March 11, 2008, launched a new Web page, and issued several other guidance documents. However, the Agency does not have a comprehensive standard that addresses combustible dust hazards. OSHA will use the information gathered from the NEP to assist in the development of this rule.
The purpose of this memorandum is to provide guidance in calculating the levels of dust accumulations that may be allowed at workplaces for combustible dusts with bulk densities less than 75 lb/ft3. The guidance provided in this memorandum supplements the dust accumulation guidance provided in several sections of CPL 03-00-008, Combustible Dust National Emphasis Program (Reissued), including IX.E.3.c and d; IX.E.8; and IX.E.9.c and d.
Several sections of CPL 03-00-008, Combustible Dust National Emphasis Program (Reissued), reference 1/32 inch dust accumulation levels. This accumulation thickness is based on certain assumptions, including uniformity of the dust layer covering the surfaces and a bulk density of 75 lb/ ft3 of the material. NFPA 654 (2013) allows the dust accumulation level to exceed the layer depth criteria of 1/32 inch according to the following equation for materials with bulk density less than 75 lb/ft3:
(A) Section 1301 General
(1) 1301.1 Scope. The equipment, processes and operations involving dust explosion hazards shall comply with the provisions of this rule.
(2) 1301.2 Permits. Permits shall be required for combustible dust-producing operations as set forth in rule 1301:7-7-01 of the Administrative Code.
(B) Section 1302 Definitions
(1) 1302.1 Definition. The following word and term shall, for the purposes of this rule and as used elsewhere in this code, have the meaning shown herein.
"Combustible dust." Finely divided solid material which is 420 microns or less in diameter and which, when dispersed in air in the proper proportions, could be ignited by a flame, spark or other source of ignition. Combustible dust will pass through a U.S. No. 40 standard sieve.
(C) Section 1303 Precautions
(1) 1303.1 Sources of ignition. Smoking or the use of heating or other devices employing an open flame, or the use of spark-producing equipment is prohibited in areas where combustible dust is generated, stored, manufactured, processed or handled.
(2) 1303.2 Housekeeping. Accumulation of combustible dust shall be kept to a minimum in the interior of buildings. Accumulated combustible dust shall be collected by vacuum cleaning or other means that will not place combustible dust into suspension in air. Forced air or similar methods shall not be used to remove dust from surfaces.
(D) Section 1304 Explosion protection
(1) 1304.1 Standards. The fire code official is authorized to enforce applicable provisions of the codes and standards listed in Table 1304.1 of this rule to prevent and control dust explosions.
Table 1304.1 Explosion protection standards
R.C. 119.032 review dates: 11/01/2016
Promulgated Under: 119.03
Statutory Authority: 3737.22 , 3737.82
Rule Amplifies: 3737.22 , 3737.82
Prior Effective Dates: 7/1/79, 6/1/85, 6/15/92, 7/1/93, 9/1/95, 3/30/98, 1/3/00, 9/1/05, 7/1/07
The flash fire that burned seven workers, one seriously, in 2012 resulted from the accumulation of combustible dust inside a poorly designed dust collection system that had been put into operation only four days before the accident. The CSB investigation team concludes that the system was so flawed it only took a day to accumulate enough combustible dust and hydrocarbons in the duct work to overheat, ignite spontaneously, cause an explosion in the rooftop dust collector, and send back a fiery flash that enveloped seven workers. The CSB found that the ductwork conveyed combustible, condensable vapors above each of three tanks in the mixing room, combining with combustible particles of dust of carbon black and Gilsonite used in the production of black ink. The closed system air flow was insufficient to keep dust and sludge from accumulating inside the air ducts. But to make matters worse, the new dust collector design included three vacuuming hoses which were attached to the closed-system ductwork, used to pick up accumulated dust, dirt and other material from the facility’s floor and other level surfaces as a ‘housekeeping’ measure. The addition of these contaminants to the system ductwork doomed it to be plugged within days of startup. The report describes a dramatic series of events that took place within minutes on October 9, 2012...