Combustible Dust Presentation
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Transcript of Combustible Dust Presentation
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J Howicz 2008
J Howicz 2008
Combustible Dust
Hazards and Controls
Benjamin RossAssistant Regional AdministratorOffice of Enforcement Programs(404) 562-2300
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Combustible Dust inIndustry:
Preventing and mitigating theeffects of fires and explosions
OSHA Safety and HealthInformation Bulletin 07-31-2005
Adapted from
Deadly dust
J Howicz 2008
This presentation describes: Hazards of combustible dust Work practices Guidelines Training to protect employees
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Background
Organic Dust Fires andExplosions:
North Carolina
(6 killed, 38 injured)
Kentucky
(7 killed, 37 injured
J Howicz 2008
Organic Dust Fire and Explosion:
North Carolina
A fire at the plantcaused dust to bedispersed and explodein the ceiling space
6 were killed, 38injured
Plant and nearbybuildings wereseverely damaged
Combustible polyethylene dust accumulatedabove suspended ceilings at pharmaceutical plant
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Organic Dust Fire and Explosion:
North Carolina
The causes of the incident cited by the ChemicalSafety Board (CSB) included inadequacies in:
Hazardassessment;
Hazardcommunication;and
Engineeringmanagement.
J Howicz 2008
Organic Dust Fire and Explosion:
Kentucky
A fire at an unattended ovenignited a dust cloudcreated by cleaning
operations at a facility makingfiberglass insulation for theautomotive industry.
The explosion was fueled byresin dust accumulated in a
production area, The resin involved was a
phenolic binder used in producing
fiberglass mats.
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Organic Dust Fire and Explosion:
Kentucky
The CSB identified ineffective dust control and explosion prevention /mitigation
Both of these causes involvedproblems relating to
Hazard assessment; Hazard communication; Maintenance procedures; Building design; and, Investigation of previous fires.
J Howicz 2008
Oxygen
Confinement
IgnitionFuel
Dispersion
Dust Explosion Requirements
Adapted from CSB
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Some eventdisturbs the
settled dustinto a cloud
Dust cloud isignited andexplodes
Dust explosion in a work area
Dust settles on flatsurfaces
Dust
Adapted from CSB
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Dust explosionsAn initial (primary) explosion in processing equipment or in an area
where fugitive dust has accumulated may shake loose more accumulated dust, or damage a containment system (such as a
duct, vessel, or collector). The additional dust dispersed into the air may
cause one or more secondaryexplosions.
These can be far more destructive than aprimary explosion
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Facility Dust Hazard Assessment
dyes,
coal, metals (e.g.,
aluminum,chromium, iron,magnesium, andzinc), and
fossil fuel powergeneration.
Combustible dust explosion hazard may
exist in a variety of industries
food (e.g., candy,starch, flour, feed),
plastics,
wood, rubber, furniture, textiles, pesticides, pharmaceuticals,
J Howicz 2008
Facility Dust Hazard Assessment. . .any industrial process that reduces a combustible
material and some normally noncombustiblematerials to a finely divided state presents a potential for a serious fire or
explosion. (NFPAs Industrial Fire Hazards Handbook)
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Particles and Powders*
Size Pellets > 2mm diameter Granules 0.42mm and 2mm,
and dust particles < 0.42mm
(420m)Hazard increases as particle size
decreases
larger surface area for combustion Fine particle may have a larger role
in dust cloud ignition and explosion
propagation.
J Howicz 2008
Particles and Powders*
Dusts may occur in the process streamand cause a hazard, regardless of
starting particle size of the material
maybreakinto
or
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Facility Analysis Components
Carefully identify: Materials that can be
combustible when finely divided; Processes which use, consume,
or produce combustible dusts; Open areas where combustible
dusts may build up; Hidden areas where
combustible dusts mayaccumulate;
Means by which dust may bedispersed in the air; and
Potential ignition sources.
J Howicz 2008
Facility Analysis Components
Identify and follow the applicablefederal, state, and local lawsand regulations. Somecommonly applicable mandatoryrequirements
OSHA General Duty Clause andStandards
The International Code Councils
International Fire Code NFPAs Uniform Fire Code.
29 CFR 1910
Local building codes frequently adopt NFPAdust standards by reference
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See
Explosivesregulations
Dust Combustibility
The primary factorin anassessment of thesehazards is whether thedust is in factcombustible.
*Determine if a dust cloudwill:DetonateDeflagrate Present a fire hazard
Or will Not burn orignite
Testing may be necessary
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Dust Combustibility
Combustible dust per NFPA 654
Prior to 2006 - Any finely divided solid materialthat is 420 microns or smaller in diameter(material passing a U.S. No. 40 Standard Sieve)and presents a fire or explosion hazard whendispersed and ignited in air.
*2006 Edition A combustible particulate solid thatpresents a fire or deflagration hazard whensuspended in air or some other oxidizing mediumover a range of concentrations, regardless ofparticle size or shape.
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Dust Combustibility
*OSHA work site health Limits (PELs) 2.5 ug/m3
(.0000025g/m3) through 15 mg/m3 (.015 g/m3)
Explosive range for combustible dusts 15 g/m3
through (Approx.) 1200 g/m3
0 250 500 750 1000 g/m3
Dust cloud concentration
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*25 watt light bulbprobably can not be seenthrough ten feet of acombustible dust mixture
Dust Combustibility
Whatbulb?
25 watts
2 meters
Glass Glass
40 g/m3 concentration ofcomb. dust suspended in air
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What is wrong here?
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Dust CombustibilityInformation sources (some better than
others) As used test data Chemical supplier test data MSDS sheets Published tables Variables
Particle size, Shape
Moisture content. Changes in the material
produced by processequipment.
Many others
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Electrical classification
OSHA Electrical standard(29 CFR Part 1910 Subpart S)
NFPA 70, the NationalElectrical Code.
NFPA 499, . . . Classificationof Combustible Dusts and of
Hazardous (classified)
Locations for Electrical
Installations in ChemicalProcess Areas.
ElectricalEquipmentClass IIDivision 1Division 2Group A
B
C
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Other Hazard Analysis
ConsiderationsSome subjective (and not always accurate) rules
of thumb
*Begin cleaning when dust reaches
When you can write in it
When it obscures the color of the surface
1/64th inch thick
1/32nd inch thick
1/16
th
inch thick 1/8th inch thick
Really no need to clean - if it hasnt exploded by now,
it wont
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Dust ControlNFPA 654 - contains
comprehensive guidanceSome of its recommendations:
Minimize the escape of dust
from process equipment orventilation systems;
Use dust collection
systems and filters;
Utilize surfaces thatminimize dust
accumulation and facilitate
cleaning;
Spotsare not
raindrops
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?
NFPA 654 guidance
Provideaccess to allhidden areas topermit inspection;
Inspect for dustresidues in openand hidden areas,at regular
intervals; Clean dustresidues atregular intervals;
Dust Control
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Dust Control
NFPA 654 guidance
Use cleaning methodsthat do not generatedust clouds, if ignitionsources are present;
Only use vacuumcleaners approvedfor dust collection;
HAZ LOC
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Ignition ControlNFPA 654, identifiescomprehensiveguidance
Use appropriateelectrical equipment andwiring methods;
Control static electricity,
including bonding ofequipment to ground;
Control smoking, openflames, and sparks;
No!
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Ignition Control
NFPA 654 -guidance Control mechanical
sparks and friction;
Use separator devices
to remove foreign
materials capable ofigniting combustibles fromprocess materials;
Separate heatedsurfaces from dusts;
Magnetic
Core
Non - Magnetic
rotating drum
J Howicz 2008
Ignition Control
NFPA 654 -guidance
Separate heating
systems from dusts;
Proper use and typeof industrial trucks;
Proper use ofcartridge activated
tools; and Adequately maintain
equipment.
Hotworkpermit
_________
_________
_________
_________
Grinder
Kaboom!
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Ignition Control
Other ignitionsources
Use appropriate Class IIElectrical equipment andwiring methods whererequired
OSHA 29 CFR 1910.178(c) regulates poweredindustrial trucks in dust
areasCoal handling operations
must comply with OSHA29 CFR 1910.269
Class I & II
Group D & G
J Howicz 2008
Hazardousvertical surfaceaccumulation
Employees needto be trained
To recognize andprevent hazards
associated withcombustible dust
In takingpreventative action,
and/or
How to alertmanagement.
Training
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TrainingThey need to know
The safe work practices applicable totheir job tasks,
The overall plant programs for dustcontrol and ignition source control.
Training must be
Before they start work
Periodically to refresh their knowledge
When reassigned
When hazards or processes change
J Howicz 2008
TrainingManagement Responsibility
Comply with the Hazard CommunicationStandard
Have a qualified team conduct a facilityanalysis (or have one done by qualified outside
persons) prior to the introduction of a hazard and
Develop a prevention and protection scheme
tailored to the operation.List of
Chemicals
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TrainingSupervisors and managers
should be aware of and supportthe plant dust and ignitioncontrol programs.
Their training should includeidentifying how they canencourage the reporting ofunsafe practices and facilitate
abatement actions.
J Howicz 2008
IMPERIAL SUGARIMPERIAL SUGAR
COMPANYCOMPANY
Port Wentworth, Georgia
Facility constructed in 1917; purchased by ISCin 1997
2nd largest sugar refinery (300+ acres)
Publicly traded
Largest sugar refiner in country-2001
Bankrupt in 2001, sold off most facilities
850 employees total; 400 at Port Wentworth Refines cane sugar into granulated,
confectioners (powdered) sugar, brown sugar,liquid sugar and specialty sugars
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J Howicz 2008
Overview of EventOverview of Event
February 7, 2008 @7:16pm catastrophic dustexplosion
8 employees killed immediately; 40 employeesinjured
19 victims admitted to Augusta Burn Center; 5 diedfrom their injuries; 3 remain hospitalized
13 total employees killed
CEO in plant at time of event
117 employees onsite; 29 contract employees
7 total contractors; 3 contractors on site at time ofevent; 2 of the fatalities were contract employees
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Response
SAV AO arrives on-site @ 8:45pm Established contact and entered into ICS
Assistant Safety Officer
Investigation Team
Initiated Compliance Assistance support until 2/15
Police & Fire State Fire Marshall (Arson Investigation) ATF National Response Team (Criminal Inv) Chemical Safety Board
Entered site agreement with OSHA & company
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THE INVESTIGATION OSHA onsite within one and half hours Began interviews upon release from ATF February 15 Interviews of 200+ employees and managers (not
including contractors) Over 1,000 hours of interviews & depositions Collection and evaluation of physical evidence to
determine cause of explosion Collection & review of over 20,000 documents, 7
subpoenas issued Comprehensive inspection of all accessible parts of
facility Limited engineering documentation maintained OSHA camper and trailer
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Deflagration - WorkingDefinition
Propagation of a flame or combustionzone through a mixture of a fuel andoxidizer (usually air) producing a pressurefront and flame front that propagate fromthe point of ignition at a rate that is slowerthan the speed of sound in the unburnedmixture.
J Howicz 2008
Deflagration
Deflagrations liberate large quantities ofheat very rapidly. Increases the air temperature rapidly
Causes the air and combustion product gasesto expand rapidly (8X for sugar)
Rapid heating and expansion causes largepressures to develop
Large pressures cause structural failure
Heat and structural failure cause personnelinjuries
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Necessary Conditions for DustDeflagration
Four conditions must be met: Combustible particulate solid of sufficiently
small particle size to be deflagrable.
Deflagrable particulate is suspended in air (orother oxidizing medium)
Deflagrable particulate suspension ofsufficiently high concentration.
A competent igniter applied to the suspensionwhere the concentration is sufficient for flamepropagation.
J Howicz 2008
Necessary Conditions for Dust
Deflagration
All four (4) conditions must be met in the sameplace and at the same time.
Deflagrable particulate.
Suspension
Sufficient Concentration.
Competent igniter applied to the suspension where
the concentration is sufficient for flame propagation. Consequently, deflagrations are rare events with
devastating consequences.
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Hazardous Particulate
Largest particles
Smallest particles
Every large compartment is a particulateseparator, separating particles by mass.
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The Typical Explosion Event
Most dust explosions occur as a series ofdeflagrations (secondary events) instages.
While a single explosion is possible it is theexception rather than the rule.
Most injuries are the result of the secondary
deflagrations rather than the initial event, inthis case - ALL of them
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The Typical ExplosionEvent
Factory
Time, msec.
0 25 50 75 100 125 150 175 200 225 250 300 325
Process
Equipment
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The Typical Explosion
Event
ProcessEquipment
InitialInternalDeflagration
Time, msec.
0 25 50 75 100 125 150 175 200 225 250 300 325
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The Typical ExplosionEvent
ProcessEquipment
InitialInternalDeflagration
Shock Wave
Time, msec.
0 25 50 75 100 125 150 175 200 225 250 300 325
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e yp ca xp os on
Event
ProcessEquipment
InitialInternalDeflagration
Elastic ReboundShock Waves
Time, msec.
0 25 50 75 100 125 150 175 200 225 250 300 325
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The Typical Explosion Event
Time, msec.
0 25 50 75 100 125 150 175 200 225 250 300 325
ProcessEquipment
InitialInternalDeflagration
Dust clouds causedby Elastic Rebound
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The Typical Explosion Event
ProcessEquipment
ContainmentFailure from InitialDeflagration
Dust Clouds Causedby Elastic Rebound
Time, msec.
0 25 50 75 100 125 150 175 200 225 250 300 325
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The Typical Explosion Event
ProcessEquipment
Secondary DeflagrationInitiated
Dust Clouds Causedby Elastic Rebound
Time, msec.
0 25 50 75 100 125 150 175 200 225 250 300 325
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The Typical Explosion
Event
ProcessEquipment
Secondary DeflagrationPropagates through Interior
Time, msec.
0 25 50 75 100 125 150 175 200 225 250 300 325
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The Typical Explosion Event
ProcessEquipment
Secondary DeflagrationVents from Structure
Time, msec.
0 25 50 75 100 125 150 175 200 225 250 300 325
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The Typical Explosion Event
Secondary DeflagrationCauses Collapse and Residual Fires
Time, msec.
0 25 50 75 100 125 150 175 200 225 250 300 325
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Evaluation of Causal Factors Dust emissions/housekeeping Dust collection systems Ignition Sources
PITs Electrical
Mechanical
Prevention Systems Deflagration venting
Explosion suppression systems
Explosion isolation devices Life Safety Fire Protection
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WHAT HAPPENED?
Rodding of Silo 1 all day resulting inadded fuel load in tunnel
Initiating event inside East PackagingProduction Bucket Elevator
Secondary explosions in the silogallery and the tunnel
Flame front and overpressurizationadvances through packing houses andinto adjacent buildings
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PROPOSED VIOLATIONS
Egregious willful: 12 instances of housekeeping by location
(1910.22(a)(1) & (a)(2))
44 instances of electrical equipment not classified forarea (1910.307(c)(1)(i))
5 instances of powered industrial trucks not classifiedfor the area (1910.178(c)(2)(vii))
8 Willful violations: Explosion prevention systems (5a1)
Dust collection deficiencies (5a1) Operation of sweeper in hazardous locations (5a1)
Fall Protection (1910.22 & 23)
Unguarded belt & pulley (1910.219(d)(1) & (e)(3)(i)
J Howicz 2008
PROPOSED VIOLATIONS
51 Serious violations Dust collection system installed improperly (5a1) Masonry construction of exterior wall in powder room (5a1) Conveyor belts with no sensors (5a1); Maintenance of boilers (5a1) Stairs & Ladders Egress Manlifts Fire extinguishers
Machine Guarding Welding Electrical Lead Maritime
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Housekeeping & Dust
Emissions EE statements, emphasis on production Calculation for fuel load Company created MSDSs
Numerous previous fires, including week before event Explosion at Domino, November Audit Reports (Insurance, AIB, internal) LO/TO Procedure Photos depicted heavy accumulations Injury/illness reports (injury and illnesses documented accumulations) Corp Safety Manager
Stated to have no responsibility over housekeeping, considered food quality issued Emailed managers that condition of facility was bad
VP of Ops Worst facility he has ever seen Didnt know places like this still existed in America
Told facility management they would end up in body bag Placed CEO on notice, told to cool it. Also told to give a positive response to board Spoke of accumulations up to waist deep throughout packing houses
J Howicz 2008
Other Critical Evidence Electrical
EE, mgr statements Didnt classify hazardous locations, did @ Grammercy facility Training document detailing requirement Laundry list of equipment not rated for Class II, Div 1 or 2 Insurance audits, placed on notice of unapproved devices No one assigned responsibility in selection/purchase
Deflagration protection Mgr & engineer statements
Insurance Audits (Grammercy) Protective systems in place at other company facilities One bucket elevator vented & dust collectors vented
Isolation (rotary valves) used Dust Collection
Engineering audits (poor design & maintenance) Duct velocities 20-50% designed capacity-18 months
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TOTAL PENALTIES
$5,062,000
Egregious: $4,270,000
Willful: $560,000
Serious: $232,000
J Howicz 2008
Helpful Hints
Manage the scene, dont let it manage you! Establish good communication Evidence collection
Professional input/opinions Photos Interview statements
Identify & establish base of ops Establish document collection system Demolition/Evidence collection involvement Thorough interviews!! Create Timeline (interviews, 911 calls, emerg resp docs)
Manage Photos Plan, delegate, & monitor activities Plan, obtain, & use resources wisely (personnel & equipment) Keep team focused on mission! Good communication with RO and NO. NO SURPRISES!!! Careful w/ CSB