Webinar: Combustible Dust: From Sparks to Fires to Explosions

Over 500+ combustible dust related incidents in 2011 according to U.S Fire Administration (Department of Homeland Security) NFIRS reports. Find out more with free webinar ON DEMAND

Since the 2009 introduction of OSHA’s proposed combustible dust rulemaking following the 2008 Imperial Sugar Refinery catastrophic dust explosion, a regulation has not been finalized. In the interim, Congress has acted with the February 2013 reintroduction of a proposed combustible dust bill, “Worker Protection Against Combustible Dust Explosions and Fires Act (H.R. 691),” which directs OSHA to immediately publish an interim combustible dust regulation.

A problem arises in both the proposed OSHA combustible dust rulemaking process and reintroduced combustible dust bill in that neither acknowledges the multitude of “near miss” combustible dust related fires, precursors to catastrophic dust explosions and flash fires. In 2013 a preliminary analysis by the Combustible Dust Policy Institute (CDPI) of National Fire Incident Reporting System (NFIRS) 2011 data provided by the National Fire Data Center at the U.S. Fire Administration indicated over 500 combustible dust related incidents. The majority of these incidents are “near miss” fires in the manufacturing and non-manufacturing sectors with dust, item first ignited.

This webinar will provide valuable information on how partnering with the nation’s fire service assists facility owners, managers, and OHS professionals in identifying combustible dust hazards, preventing incidents, and reducing liability. The presenters will discuss the fire service’s response to the prevalence of repeatable “near miss” combustible dust-related fires occurring throughout U.S. industry.

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Vacuum Collection Systems Designed for Explosive Dust Atmospheres

When milling, machining, polishing, grinding, or drilling materials such as Titanium, Magnesium, Aluminum, Iron Oxides, Stainless Steel, and Carbon Fiber, manufacturers must address the inherent explosion and fire hazards associated with the combustible dust generated by these materials.

NFPA 484 Annex // A.3.3.6.1 Combustible Metal Dust.*

3.3.6.1* Combustible Metal Dust. “A combustible particulate metal that presents a fire or explosion hazard when suspended in air or the process specific oxidizing medium over a range of concentrations, regardless of particle size or shape.”

An overall system solution must address the process requirements, materials, and the volumes processed. All equipment in contact with hazardous / combustible dusts must be constructed in compliance with HazLoc  Class II disciplines, and applicable N.F.P.A., A.N.S.I.,  and A.S.M.E. standards.  Customized systems are usually application specific and sized appropriately for the collection, conveyance, and control of the materials, ratios, and anticipated volumes of debris to be recovered. 

A basic understanding of the issues and solutions as relate to current developments in systems configurations, and best industry practices requires an explanation as to how catastrophic events occur.  In the interest of enhanced worker and plant safety we will also review what can be done to prevent them.

FIRE:                 

               

Direct:

Combustible dust related fires occur in all cases as a result of combustible materials being exposed to an ignition source.  This can occur either during or subsequent to machining when materials are within ignition sensitivity levels capable of supporting a deflagration.

During Transfer:      

When being transferred for collection, combustible dusts can also impact duct work elbows and other constrained joints and as a result of high speed impact create a spark moving the ignition source toward a collection point.  Non-grounded components accumulating an electrostatic charge, exposure to electrical motors or other spark producing equipment can also provide an ignition source.

Collected:

If an ember or spark is eventually transferred to a collection location and maintains ignition energy it can initiate a further transfer of the ignition to additional materials in the process stream.

Accumulated Residuals:

Layers of dust which have accumulated over time have also been documented as transmitting an initial deflagration to secondary areas. In a worst case scenario if suspended as a dust cloud, explosions are easily generated as the deflagration gains rapid expansion due to the increase of combustibles.

EXPLOSION:

Suspension: 

Dust explosions occur when combustible materials are suspended in an air/fuel concentration consistent with rapid ignition transmission. If the initial deflagration generates even a primary explosion, the associated shock waves will dislodge any dusts which have accumulated over time on overhead beams, walls, duct work, machinery, or collection vents. When these materials are dislodged from their resting place, they become airborne and in the presence of the initial flame front ignition source presented by the initial deflagration, they will contribute to an even much larger secondary catastrophic explosion.  Incidents reported in recent years here in the U.S. have documented multiple deaths, injuries, and significant property destruction.

COMINGLED MATERIALS:

 

S.D.S. (SAFETY DATA SHEETS) seldom refer to the inherent danger of finite dust particles generated during machining processes. They fall short by NOT expressing the M.I.E. (Minimum Ignition Energy) and minimum ignition temperature (MIT) thresholds and seldom address the issue of reactivity with other materials.  In some industries such as aerospace, there are usually several materials in a waste stream.  As an example, drilling and assembling aircraft structures will generate carbon fiber, titanium, aluminum, and stainless steel in varying combinations.  These comingled materials lead to secondary handling issue that S.D.S. specifications don’t address. Using one collection system for recovering different materials from diverse operations should be evaluated by sample testing to determine if a volatile combination of materials with lower MIE than each by themselves may be present.

HOUSEKEEPING:

Housekeeping, provides increased worker and plant safety but usually adds to the overall cost of manufacturing operating expenditures.  Safely removing accumulated combustible dusts requires specialized equipment and in some cases access can only be achieved if entire production areas are shut-down.  As a result, cleaning activities are not performed as frequently as they should be thus increasing the risks associated with accumulated combustible dusts. To minimize personal risks, efforts should include materials safety awareness, safe handling protocols and training. For example, using plant compressed air to “blow-off” debris from recessed areas should be avoided as the resultant dust in suspension could easily propagate an explosion under the right conditions.

TESTING:

When dealing with any of the debris generated within the production waste stream, one of the first steps must include combustible dust testing of the materials for explosive severity and ignition sensitivity as they would be generated in the work environment.  Sample collection(s) and submittal to an independent laboratory for testing under N.F.P.A. Code 68 is essential. Data received from such test results is mandatory when designing fire prevention and explosion protection equipment and process systems with sufficient capacities to safely accommodate subsequent collection, conveyance, and containment of the materials being recovered.

 A PRO-ACTIVE SOLUTION:  COLLECT – CONTROL – CONTAIN

Central Vacuum System

Current systems have incorporated both high volume air flow AND high vacuum to optimize collection efficiencies and transfer capabilities of heavy combustible dusts.   The ability to collect and control the transfer of any debris or dust is related directly to the volume, size, weight, specific gravity, and surface area of the material to be addressed.  Vacuum in itself provides no means to act upon any material unless there is substantial air volume available to generate the motive force behind transfer.  Dust collectors generally rely upon large volumes of air flow and as a result impart minimal vacuum on materials to maintain their velocities in collection ducts. 

Collect dust as it is being generated.

Hazardous dust migration in many cases has been eliminated by using specialized high volume – high vacuum / dust recovery systems to collect debris simultaneous to generation further containing the recovered materials and minimizing the burden of house-keeping. Within the aerospace industry, complete recovery of drill chips and dust at the work piece is currently in use on several projects and in automotive applications, debris recovery has been accomplished within assembly and machining operations with the same process.

Control dust during transfer:

The recovery of combustible particulate solids must assure that air/material ratios never approach critical M.E.C. (Minimal Explosive Concentrations) which could support ignition resulting in a deflagration which could travel either up or down stream of the event. M.E.C. ratios vary based on materials and process requirements, however the speed at which materials are transferred and the separation of these materials by excessive air volumes provides a means to isolate one particle from the next. High volume rate transfer also maintains the materials in suspension which minimizes their contact with duct work thus reducing the build-up of fines, clogs, static, and sparks

Contain dust for safe disposal:

Many terms apply to the initial separation of the combustible dusts from the recovering air stream such as Vortex, Centrifugal, or Gate type systems. Initial contact between recovered dusts and the receiving receptacle act to slow the materials in the air stream such that heavy materials drop out of the airstream before contact with any filtering media. General dust collectors employ filter “bag-house” configurations with high pressure air jets to back flush the filters on occasion to maintain collection capabilities as the finer materials in these type systems have a tendency to migrate into the filter media. Rotary valves or gates at the bottom of the recovery receptacles allow recovered materials to be collected for disposal.

SYSTEM FEATURES:

Items which may have been considered as “OPTIONAL” in the past should be considered as MINIMAL requirements in systems collecting and conveying combustible dusts in compliance to HazLoc Class II.  Terminology may differ between industries and suppliers however the intent to which these are applied remains consistent with providing safety in the work place.                        

 Specifically best industry practices include:

Grounding – and incorporating non-spark producing elements, materials, motors, switches

Spark / Heat detection – includes multiple high temperature rise sensors

Explosion detection – detect first pressure wave of an initial explosion ( see isolation below )

Explosion venting – pressure relief and / or rupture disk,  vents explosion toward a safe area

Flame / Fire / Deflagration  Suppression – appropriate to the material(s) being encountered

Flameless venting – prevents flame travel beyond location of occurrence

Isolation-Explosion gates – prevents flame travel “up-stream” or to other process areas

Minimized debris contained for safe daily removal

Plant personnel education, awareness and training

Author: J. Byron Walker is Director for Systems Design and Engineering @ TECH TRANS UNLIMITEDCORP.  He has over 35 years of experience in Robotics and automation systems integration working in the automotive, aerospace, and electronics industries.  He holds patents in finite parts cleaning technologies and is responsible for providing total systems solutions for the safe recovery and transfer of Hazardous Materials to which this article is directed.

Wisconsin Combustible Dust Hazard Awareness Seminar, May 16

Full-day Combustible Dust Hazard Awareness Seminar. May 16, 2013, Northcentral Technical College, Wausau, Wisconsin. Workplace combustible dust related fires and explosions occur with alarming regularity throughout the global grain, mining, manufacturing and non-manufacturing sectors. Historically, many of these non-consequential incidents have escalated into catastrophic events. Subsequently, this educational seminar will provide stakeholders with the basic knowledge and skills in minimizing the probability of occurrence and severity of consequence of future combustible dust related incidents in addition to maintaining OSHA regulatory compliance.

Seminar agenda will include:

• Introduction to OSHA Regulations and NFPA Combustible Dust Standards

• Identifying combustible dust hazards

• Evaluating combustible dust hazards

• Administrative and engineering control measures

• Facility inspection and risk assessment

Date: May 16, 2013

Time: 9:00 a.m. - 5:00 p.m.

Location: NTC Wausau Campus

Price: $50

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Media Must Cease in Referring West, Texas Facility as a Fertilizer Plant

Fertilizer Plants Defined 101 from Combustible Dust Policy Institute

Quite alarming when nation-wide stakeholders don't believe they have anything in the magnitude of the West, Texas facility such as a fertilizer manufacturer yet have establishments supplying fertilizers to farmer end-users

Don't kid yourself folks, West Fertilizer was not a fertilizer manufacturer either, as the media incorrectly portrays in many instances. The Texas establishment supplied custom blended fertilizer to farmers in the area as a retail establishment in addition to operating a grain handling facility, yet exempt under the OSHA Process Safety Management (PSM) Standard, while handling a Highly Hazardous Chemical (anhydrous ammonia).

The media incorrectly labels the facility as a fertilizer plant. So a bakery that customs mixes flour and sugar is a flour mill or sugar refinery? As a result of this inaccurate information many stakeholders  don't believe they have potential fire and explosion hazards in their backyard.

This is a dangerous trend where safety professionals must educate the media on the facts before others incorrectly believe no hazards exist. Unfortunately Texas authorities did not learn from the Magnablend catastrophe  especially in regards to Local Emergency Planning Committees (LEPC).

NAICS 42451: Grain and Field Bean Merchant Wholesalers, in addition to West Fertilizer covered under EPA RMP handling anhydrous ammonia with OSHA PSM exemption.

Total number of facilities: 82
Number of deregistered facilities: 10
Number of processes that could reach off-site: 82
Total pounds of toxic chemicals in processes: 28,355,310
Total pounds of flammable chemicals in processes: 0
Number of 5-year accidents: 4
Number of deaths from 5-year accidents: 0
Number of injuries from 5-year accidents: 4
Amount of property damage from 5-year accidents: $0

NAICS 424910, Farm Supplies Merchant Wholesalers, additional establishments in USA under EPA RMP handling anhydrous ammonia with OSHA PSM exemption

Total number of facilities: 3,645
Number of deregistered facilities: 601
Number of processes that could reach off-site: 3,738
Total pounds of toxic chemicals in processes: 6,728,564,906
Total pounds of flammable chemicals in processes: 392,870
Number of 5-year accidents: 138
Number of deaths from 5-year accidents: 3
Number of injuries from 5-year accidents: 191
Amount of property damage from 5-year accidents: $209,774

NAICS 493130, Farm Product Warehousing and Storage. in addition to West Fertilizer covered under EPA RMP handling anhydrous ammonia

Total number of facilities: 260
Number of deregistered facilities: 121
Number of processes that could reach off-site: 267
Total pounds of toxic chemicals in processes: 101,485,227
Total pounds of flammable chemicals in processes: 72,000
Number of 5-year accidents: 5
Number of deaths from 5-year accidents: 0
Number of injuries from 5-year accidents: 4
Amount of property damage from 5-year accidents: $0

RMP was last updated on RTK Net with a set of EPA data made on May 30, 2012

TIER II Reporting To SEPC and LEPC's

Tier II in conjunction with LEPC' is a key element where many chemicals are not triggered with  thresholds in the EPA/RMP or OSHA/PSM programs. In contrast, TIER II when used as intended by the LEPC's engages the necessary hazard awareness on the other side of the fence-line throughout the community in preventing, planning and preparing for future accidents.

What is a Texas Tier Two Report?
"Two types of thresholds that determine whether a hazardous chemical will be included on the Texas Tier Two Report:

#1. There are very low thresholds for any of the listed EPA Extremely Hazardous Substances (500 pounds or the Threshold Planning Quantity in pounds for the specific listed chemical, whichever amount is less).

#2. For all other "generally hazardous chemicals" products which require a Safety Data Sheet (SDS) under the federal Occupational Safety and Health Administration's (OSHA's) Hazard Communication Standard], the threshold for reporting is 10,000 pounds."

LIST OF LISTS
• EPCRA Section 302 Extremely Hazardous Substances
• CERCLA Hazardous Substances
• EPCRA Section 313 Toxic Chemicals
• CAA 112(r) Regulated Chemicals For Accidental Release Prevention

"This consolidated chemical list includes chemicals subject to reporting requirements under the Emergency Planning and Community Right-to-Know Act (EPCRA), also known as Title III of the Superfund Amendments and Reauthorization Act of 1986 (SARA), Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and chemicals listed under section 112(r) of the Clean Air Act (CAA).

This consolidated list has been prepared to help firms handling chemicals determine whether they need to submit reports under sections 302 and 313 of EPCRA and determine if releases of chemicals are reportable under CERCLA and section 304 of EPCRA. It will also help firms determine whether they will be subject to accident prevention regulations under CAA section 112(r)"

3rd IND EX Safety Congress Nuremberg, Germany April 24-25

 

Nuremberg Castle
Photo Credit: Vitold Muratov

Industrial explosion protection IND EX Safety Congress  in conjunction with POWTECH 2013 International Trade Fair for Mechanical Processing Technologies and Instrumentation.For instance, at  POWTECH 2011: 704 exhibitors from 73 countries, 15,498 trade visitors (including TechnoPharm)

Two days of explosion protection session topics which also includes live dust explosions (outdoors) at the Nürnberg Convention Center. IND EX, the German based Association of Experts for Explosion Safety, organizes this two day extravaganza. Keynote Speaker: Dr. Bert Reichert -Nürnberg Hospital for Burn Traumas- "Fatal consequences of insufficient safety concepts - burn and explosion traumas to the human body."

Sessions chaired by Dr.-Ing. Johannes Lottermann, Dipl.-Ing. Richard Siwek, and Stefan Penno

Presentation topics include:

• Dust explosion in a Fiber Board Factory

• Protection of Mixers and Blenders against explosions

• Combustion of Biomass - Influence of material specifications on explosion protection measures

• Are we sure that certified safety systems are really safe?

• Trends in norms, guidelines vs. old school approaches from the past

• The design of explosion proof Battery Rooms for solar driven boats and consequences for other applications in the field of renewable energy

• Modeling of Dust Explosions to determine optimum protection when EN standards and codes are not relevant or considered too conservative

• State of the art in explosion isolation

• Of using a belt as well as additional suspenders: Explosion safety repeated unnecessarily

• Explosion safety goes South America - about the ABNT + its standardization efforts in Brazil

• Simplified explosion protection of filters - explosion venting, explosion isolation + improved separation all in one

•  CFD simulations of the 20 liter explosion vessel

• Dispersion of two-phase jets from accidental releases in hydraulic pipes
• Hydrogen Hazards

 

 

Fact Sheet: 2011 Combustible Dust Related Incidents, NFIRS Analysis

Fact Sheet: 2011 Combustible Dust Related Incidents, NFIRS Analysis from Combustible Dust Policy Institute

A Combustible Dust Policy Institute (CDPI) preliminary analysis of 2011 National Fire Incident Reporting System (NFIRS) incident data provided by the National Fire Data Center of the U.S. Fire Administration indicated over 500 combustible dust related incidents in manufacturing facilities where dust was the item first ignited. Near misses include incidents that did not result in any harm to personnel, the facility, process, or product. Analysis did not include the grain sector or coal-fired energy plants.

Additionally, the CDPI analysis does not include many incidents that were not reported by fire departments to the National Fire Data Center. As a result there are many more combustible dust related incidents that cannot be evaluated in determining whether the incident was a near miss or not. 

Special thanks to the nation's Fire Departments, NFIC State Program Managers, and the National Fire Data Center at the U.S. Fire Administration in sharing this valuable Information.  

Casual Pathways Between Near Misses and Catastrophic Events 

Excellent article by Carsten Busch from Norway, highlighting Common Cause Hypothesis (CCH) which also pertains to near misses and catastrophic combustible dust related incidents. In the current OSHA ComDust rulemaking process and recently reintroduced proposed combustible dust bill H.R. 691, incidents resulting in property/content loss (30% NFIRS analysis) yet no casualties (approximately 95%) are considered near misses. Yet the casual pathways (ignition sources, dust management strategies, etc.) for the consequences of all combustible dust related incidents are all the same. 

The true definition of a "near miss" is an incident not resulting in any harm to personnel, the facility, process, or product. So why are near misses ignored in accounting for combustible dust related fire and explosion hazards in protection of the workplace in the OSHA ComDust rulemaking process and recently reintroduced proposed combustible dust bill H.R. 691?

Report on preliminary findings of a study of incident reporting systems for near misses in non­medical domains. This can also apply to combustible dust related incidents/accidents where NFIRS data provides a multitude of information in developing barriers for the prevention of future accidents.

Near Misses in Non­-medical Domains

"Consequently, the same patterns of causes of failure and their relations precede both adverse events and near misses." Sounds familiar with ComDust related incidents at facilities whether it was flash fire, dust explosion, or layer fire? They all have casual pathways of improperly managed ignition sources and fuel sources. A written fire prevention plan (FPP) addresses these casual pathways initially at the organizational level. The next step would be implementation at the technical and operational level.

"We defined a near miss as any event that could have had adverse consequences but did not and was indistinguishable from fully fledged adverse events in all but outcome." Note: National Fire Incident Reporting System (NFIRS) was not included in the report of near misses in non­medical domains. 

U.S. Chemical Safety Board (CSB): Near Misses.
Dust Explosion Hazard Awareness / Imperial Sugar Management and Workers
(Page 54 .pdf) "The CSB concluded that the small events and “near-misses” caused company management, and the managers and workers at both the Port Wentworth, Georgia, and Gramercy, Louisiana, facilities to lose sight of the ongoing and significant hazards posed by accumulated sugar dust in the packing buildings."

CSB Key Findings: Imperial Sugar Refinery
Page 48 .pdf)  # 4 "Company management and the managers and workers at both the Port Wentworth, Georgia, and Gramercy, Louisiana, refineries did not recognize the significant hazard posed by sugar dust, despite the continuing history of “near-misses’”

Hoeganaes
(Page 14 ,pdf) "Operators and mechanics reported being involved in multiple flash fires during their employment at the Gallatin facility. At the time of the incidents, many were aware that the iron dust could burn or smolder. However, they were not trained to understand the potentially severe hazard when accumulated dust is dispersed in air. Rarely would operators report the minor flash fires and “near-misses” that periodically occurred."

(page 27 .pdf) CSB Recommendations to Hoeganaes 2011-4-I-TN-R9
"Develop and implement a “near-miss” reporting and investigation policy that includes the following at a minimum:"
• Ensure facility-wide worker participation in reporting all near-miss events and operational disruptions (such as significant iron powder accumulations, smoldering fires, or unsafe conditions or practices) that could result in worker injury.

• Ensure that the near-miss reporting program requires prompt investigations, as appropriate, and that results are promptly circulated throughout the Hoeganaes Corp.

• Establish roles and responsibilities for the management, execution, and resolution of all recommendations from near-miss investigations

• Ensure the near-miss program is operational at all times (e.g. nights, weekends, holiday shifts).  

Conclusion 

Near misses can no longer be ignored. It's very distressing that OSHA in the combustible dust rulemaking process in conjunction with the legislators in the reintroduction of the proposed combustible dust bill H.R. 691 have chosen to ignore 95% of combustible dust related incidents in manufacturing facilities, which do not result in personnel casualties. Yet these very same incidents, as history illustrates are precursors to catastrophe.