Combustible Dust Safety

John NewquistDraft 6 1 2017

Coal Dust

• Throughout a twenty‐five year (1980‐2005) study of PRB coal‐fired power plants, there were an average of 11 fires or explosions, 29 injuries, and 5 deaths per year.

• Another study conducted by the United States Department of Labor during the 1996‐2009 time period noted 437 workplace coal power‐related deaths, averaging 33 deaths per

year in the United States..

Will County Power Plant Crusher Building Explosion

April 2017

May 2017

•On May 31 at approximately 11 p.m., an explosion occurred at our milling operations located in Cambria, Wisconsin.

•The cause of the explosion is not known

•Corn milling

Apr 2017

• Dust collection systems must be installed which will safely capture potentially explosive aluminum fines.

Metallic dusts from grinding, sawing or cutting should be picked up by one collection system, while dusts from buffing and polishing should be picked up by a different system. This will prevent the mixing of explosive and flammable dusts.

March 2017

May 2017

NFPA requires that an explosion isolation device be installed on all suction side ducts that transport material with a KST value above zero.

KST values are used to measure the speed at which pressure rises during a standard explosion severity test.

EcoMAXX™ No Return Valve

August 2012

• WESTON, Mo. -- More than 200 people were briefly evacuated after a small explosion and fire at Kansas City Power & Light's Iatanpower plant in Weston.

• Coal bunker.

• Platte County fire crews were dispatched to the coal-fired power plant and quickly contained the blaze.

September 2016

• Francesville, IN

• An employee was operating the north leg of a grain elevator.

• Grain was being emptied from a semi-trailer into the north pit and then being sent to the wet holding bin when a grain explosion occurred.

• The employee received burns to his body resulting in his death.

• 67/M

February 2016

• Rockmart, GA

• An employee was scooping feed pellets off the floor with a shovel.

• There was an explosion when the dust ignited and the employee was killed.

• 25/M

January 2015

• Ticonderoga, NY

• An employee was climbing a fixed ladder to change filter bags on the bag house.

• While changing, fly ash was released from the bagger or silo.

• The employee caught on fire and died as a result of extensive burns.

• 57/M

January 2015

• Farmington Hills, MI

• An employee was prepping the north sand hopper interior walls.

• A fire started when a spark, radiant heat and/or conductive heat, likely ignited the fire retardant insulation.

• One employee died (37/M) and three were hospitalized from smoke and soot inhalation with complications.

Feb 2014• Federal inspectors determined excessive accumulation of grain dust in the hammer mill area ignited and the explosion killed one worker and sent five others to area hospitals.

• The blast caused excessive damage to the building and closed the feed mill.

April 2014

• Corrigan TX

• Four people remain hospitalized, three in critical condition, after an explosion and fire at a Polk County plywood mill

• a) dust collector bags impeded the venting area of the dust collector deflagration vents.

• b) explosion vents releasing in the dust collector without taking measure to protect employees from the fireball path

• c) dust collector vented and the deflagration traveled upstream to the sander.

• d) responding to a fire within the sander dust collection system without the main blower remaining in operation.

• e) responding to a fire within the sander dust collection system without a choke between the sander dust collector and silo leading to the briquetter.

May 2014

• Hartford CT

• A workbench in the finishing room of the facility caught fire on May 19, 2014, while an employee cleaned titanium aircraft parts.

• The room's dust collection system lacked adequate fire and explosion controls.

• Flammable titanium dust had also settled on electrical equipment.

Titanium Dust Collector fire

photo

August 2014

• 75 people were killed and 185 others injured after an explosion ripped through a metal products factory in China’s eastern Jiangsu Province

Chemical Safety Board

• From 2008 to 2012, our board documented, 50 combustible dust accidents that led to 29 fatalities and 161 injuries.

July 2013

• Springdale, MO

• 1 dead, 3 burned.

• “The dust associated with the type of process goes on here resulted in some type of a flash fire that encapsulated three of the employees,” McDonald said.

July 2014

Apr 2017

• If maintenance is planned and welding or cutting is required, all machinery, ductwork and collectors must be shut down, emptied and cleaned, and all aluminum dust removed from the area and properly disposed of.

• The interior surfaces of all equipment must be carefully inspected to check for possible accumulations of fine powder, particularly at elbows, welded joints, etc. These surfaces must be wiped clean.

OSHA

• OSHA has regularly stated that NFPA standards that have not been specifically incorporated into OSHA standards or adopted by state or local jurisdictions should be considered by companies as guidance.

• At the same time, however, the NEP Compliance Directive instructs OSHA inspectors to consult the NFPA standards to “obtain evidence of hazard recognition and feasible abatement methods” to support a citation under the GDC.

• Consequently, companies should consult NFPAs when evaluating and mitigating potential combustible dust hazards at their facilities.

The Long and Winding Road

• History of Hazards

• OSHA Inspections

• Issues

• Citations

• Trends

Trend 1 – Rare Events but Still Occurring

• Two British Columbia sawmills

• Four dead and 52 injured

• Fines of up to $652,000

• Possible jail.

• These were wood dust explosions

Metal Dust - 2011

• Hoeganaes plant TN

• Four dead, two explosions

• The plant manufactures metal powder used in the automotive industry

• CSB and OSHA investigations

• The company issued a statement saying it has begun a review “to ensure that we fully understand the cause of the fire and have implemented appropriate measures to prevent a recurrence of this incident.”

• “We have already made significant progress on some of the issues raised by the CSB and we won't resume production until we are confident that all issues have been addressed.”

Grain Dust Explosion - 2011

• Oct 29, 2011

• Six dead, 2 injured

• Five Willful, 8 serious

• $400,000 penalty

• Case in court

• Lawsuit by families

Grain Elevator - 1977

• Westwego, LA

• Grain Elevator Explosion

• Dec 1977

• Spark ignited grain dust

• The explosion killed 36 people

Ford River Rouge Power Plant

• 2/1/1999

• Dearborn , MI

• MIOSHA General Duty egregious

• $1,500,000 penalty

• Natural gas boiler explosion triggered secondary coal dust explosion that had accumulated on building and equipment surfaces

• No flame sensing interlock for the gas lines

Imperial Sugar - 2008

• Feb 7, 2008

• 14 died

• 60 injured

• $180-220 million dollar est. loss

• $7,700,000 Fine – OSHA

Trend 2 – OSHA NEP continues

• Combustible Dust National Emphasis Program (NEP) –revised March 2008

• CSB issues recommendations in 2005

• Advanced Notice of Proposed Rulemaking (ANPRM) – published October 2009

• Expert panel met May 2011

• Next action???

OSHA Inspections

• Over 1000 COMDUST NEP inspections since 2008

• High Violations per inspections (Over 6.0/inspection)

Triggers are: • Complaint or referral • Media reports of fires and

explosions• Inspection Targeting List

~150-300 inspections in 2013

Sample Accident 2008

• Transfer of metal dust into mixer

• What questions would you ask?

Sample Accident Jan 2009

• The laminate panels pass on a conveyor underneath a curing UV light.

• A panel jammed up underneath the UV light.

• The panel heated up to the point where it charred, smoldered and eventually caught fire.

• The charred pieces were sucked up into the local exhaust system, where they ignited in the dust collector located outside the plant.

• The dust collector blew up, sending a shock wave back into/through the plant.

Several overhead doors were blown off, and one of these struck 4 employees, injuring them.

COMDUST NEP

• Plant history of fires• Employer’s Dust

Management System• MSDS’s• Dust Accumulation• Dust Collectors• Ventilation Specifications• One liter of dust sampled• Photos• Interviews – Employees,

Employers

Sample OSHA Questions

• What is the Plant’s Housekeeping program?

• Is there dust accumulation of 1/32 inch thick?

• Dust collectors located inside of buildings?

• Explosion relief venting distributed over the exterior walls of buildings and enclosures?

Sample OSHA Questions

• Does the facility have isolation devices to prevent deflagration propagation between pieces of equipment connected by ductwork?

• Does the facility have an ignition control program, such as grounding and bonding?

Fire through a duct is bad

Sample OSHA Questions

• Are Vacuum cleaners used in dusty areas and approved for the hazard classification?

• Are separator devices to remove foreign materials used?

• Can tramp metal ignite combustible dusts in the dust collection systems? Check the label for Class II

Sample OSHA Questions

• Is the exhaust from the dust collectors recycled?

• Does the dust collector system have spark detection and explosion/deflagration suppression systems?

Sample OSHA Questions

• Are ducts designed to maintain sufficient velocity to ensure the transport of both coarse and fine particles?

• What is the design basis for the ventilation?

• Are duct systems, dust collectors, and dust-producing machinery bonded and grounded to minimize accumulation of static electrical charge?

Sample OSHA Questions

• Is metal ductwork used? • Are bulk storage containers

constructed of noncombustible materials?

• Are employees trained in the hazards of the combustible dust?

• Are MSDSs for the chemicals which could become combustible dust under normal operations available to employees?

NEP Citations• 1910.22, Housekeeping • 1910.38, Emergency action plans • 1910.94, Ventilation• 1910.132, PPE Hazard Analysis• 1910.146, Permit-required confined

spaces • 1910.272, Grain handling facilities• 1910.307, Hazardous (classified)

locations • 1910.1000 Z table, Toxic and

hazardous substances • 1910.1200, Hazard communication • General duty clause

5/16/2002 Vicksburg, MS5 fatalities, 7 injured23 serious, 2 unclassified $210,000Fire in the baghouse, then rubber dust explosionNo explosion venting or suppression in baghouse Poor housekeeping88 fire reports in 13 years

Trend 3 – OSHA will continue to use the General Clause Violation

• Dust collectors (Air Material Separator) inside

• No proper explosion protection systems such as explosion venting or explosion suppression systems

NFPA 654 – 2013 7.13.1.1.1 Where an explosion hazard exists, air-material separators with a dirty-side volume of 8 ft3 (0.2 m3) or greater shall be located outside of buildings.There are exceptions.

Typical 5(a)(1) Violations

• Systems were not provided to prevent deflagration propagation from dust collectors to other parts of the plant.

October 29, 2003 - Hayes Lemmerz Manufacturing Plant, IN

Shawn Boone, 33, died in the Aluminum Dust explosion

Typical 5(a)(1) Violations

• No explosion relief venting distributed over the exterior walls and roofs of the buildings.

CTA Acoustics 2003 – 7 dead

Fiberglass fibers and excess phenolic resin powder probably went to the oven while workers were using compressed air and lance to break up a cogged bag house filter

Typical 5(a)(1) Violations

• Dust Collector and ducts do not prevent propagation to other parts of the plant

From BS&B

Typical 5(a)(1) Violations

• Ducts and system were not grounded

Grounding

All equipment used in the dust generating process must be thoroughly grounded to remove static electricity. “Recommended Practice on Static Electricity,” NFPA 77, should be followed.

Inspection and cleaning of all electrical equipment must be done regularly and frequently (at least weekly). Ground connections should be checked visually on a daily basis by the operators.

Typical 5(a)(1) Violations

• Airborne fugitive dust

Typical 5(a)(1) Violations

• A means of tramp metal protection was not provided to keep any unwanted metal fragments out of the air-material separators

From Duramag

Typical 5(a)(1) Violations

• Excessive dust

• Not cleaning per the appropriate NFPA Standard

Typical 5(a)(1) Violations

• Compressed Air was used for cleaning

• Tip: Clean fugitive dust• Regular program• Access to hidden areas• Safe cleaning methods• Maintain dust free as possible• No blow down unless All

electrical power and processes have been shutdown and other means cannot work.

• See NFPA

Typical 5(a)(1) Violations

• No PVC or nonconductive ducts

Typical 5(a)(1) Violations

• Not maintaining duct velocity

• Aluminum Conveyor velocity might be 4500 ft/min for pneumatic conveyors

Strategy for Employers

• Test for Combustible Dust

• Find Applicable NFPA standards

• Implement a Safety Management System

• Housekeeping• Electrical Classification• Conduct Process Hazard

Analysis for Dust Generation Processes

• Control Ignition sources

• Develop safety procedures for working on dust collectors

• Investigate leaks, hot spots, near misses

• Train Employees in hazards of combustible dust

• Plan for fires and emergencies

NFPA References

• 654 General

• 664 Wood

• 61 Agriculture

• 484 Metal

• 850 Coal Power Plants

• 70 National Electric Code

• 499 Classification of Combustible Dust

• 68 Deflagration Venting Systems

• 69 Explosion Prevention Systems

• 91 Exhaust Systems

• 2113 Flame Resistant Clothing

NFPA Objective

• Hazard control objectives:

• Prevent or limit formation of hazardous atmosphere

• Prevent ignition of the hazardous atmosphere

• Limit the consequences of a deflagration to acceptable levels (mitigation or control) Includes secondary explosion protection

Trend 4 – Employers are Testing

• NFPA 654 recommends that determination of dust combustibility be based on screening test methodology per ASTM E1226 – 2010 edition

• If dust is determined explosive, further testing may be needed to establish the properties needed for the intended protection methods

• E1226-2010 as well as NFPA 654 recommends testing in larger scale (e.g. in 1 m3) if dust is marginally explosive in 20-L apparatus.

How Much Dust is too Much?

Where are Dust Sources?

• Bag Openers (Slitters)

• Blenders/Mixers

• Dryers

• Dust Collectors

• Pneumatic Conveyors

• Size Reduction Equipment (Grinders)

• Silos and Hoppers

• Hoses, Loading Spouts, Flexible Boots

Ignition Source Control• Electrical equipment

• Hot Works

• Static electricity control

• Mechanical sparks & friction

• Open flame control

• Design of heating systems & heated surfaces

• Use of tools, & vehicles

• Maintenance

NFPA 654 - 2013

• Chapters 1 – 3Administrative

• Chapter 4 General Requirements

• Chapter 5 Performance-based Design Option

• Chapter 6 Facility and Systems Design

• Chapter 7 Process Equipment

• Chapter 8 Fugitive Dust Control and Housekeeping

• Chapter 9 Ignition Sources

• Chapter 10 Fire Protection

• Chapter 11 Training and Procedures

• Chapter 12 Inspection and Maintenance

Seven Key NFPA 654 Changes

• 4.2 Process Hazard Analysis (PHA)

• TREND 5 – PHA are conducted in less than 10% of companies, but increasing rapidly

• OSHA VPP facilities have conducted numerous PHAs

• 4.2.1* The design of the fire and explosion safety provisions shall be based on a process hazard analysis of the facility, the process, and the associated fire or explosion hazards.

NFPA 654 PHA

• Examine the facility, process, and fire and explosion hazards

• Actual test data required to support analysis

• Which materials are combustible?

• If not known, but suspected, then data are needed

• Closed or open processes?

• Rate of generation or release of solids to an environment?

• Any collection methods in place?

• Conclusion: processes generates or handles solids and dusts are formed in process, potential exists

Seven Key NFPA 654 Changes

• 4.3 Management of Change. Written procedures to manage change to process materials, technology, equipment, procedures, and facilities shall be established and implemented.

Seven Key NFPA 654 Changes

• 4.4.1* Incidents that result in a fire or explosion of a magnitude that causes property damage, production shutdown time, or injury shall be investigated.

• 4.4.3* A written report …

• 4.4.4* A summary of the incident investigation report shall be shared with affected personnel…

Seven Key NFPA 654 Changes

• 6.1.1.1 Those portions of the process and facility interior where dust accumulations exist external to equipment in sufficient depth to prevent discerning the underlying surface color shall be evaluated to determine if a dust explosion hazard or flash fire hazard exists.

Seven Key NFPA 654 Changes

• 6.1.1.3* Dust flash fire or dust explosion hazard areas shall additionally be determined in accordance with any one of the following four methods:

• Layer depth criterion method in 6.1.3

• Mass method A in 6.1.4• Mass method B in 6.1.5• Risk evaluation method in

6.1.6

The NFPA 2 day course on combustible dust covers these assessment.

Seven Key NFPA 654 Changes

• 6.2 Segregation, Separation, or Detachment of Combustible Dust Handling and Processing Areas.

• 6.2.1 General. Areas in which combustible dusts are produced, processed, handled, or collected such that combustible dust accumulation on exposed or concealed surfaces, external to equipment or containers, exceeds the threshold as determined in Section 6.1, shall be detached, segregated, or separated from other occupancies to minimize damage from a fire or explosion.

Seven Key NFPA 654 Changes• 7.3.2* Pneumatic Conveying,

Dust Collection, and Centralized Vacuum Cleaning Systems.

• 7.3.2.1 The design of the system shall be documented, and the documentation shall include the following information:

• Data on the range of particulate size

• Concentration of combustible dust in the conveyance air stream

• Potential for reaction between the transported particulates and the extinguishing media used to protect process equipment

• Conductivity of the particulates• Other physical and chemical

properties that could affect the fire protection of the process

Mitigation Ignition source control• Electrical equipment

• Class II, Division 1 and 2• Consider equipment both inside dust handling equipment and outside

• Static electricity control• Grounding and bonding are key• Inspection of ground and bonding means• Vibrating equipment (e.g., sifters) may cause fatigue failure in straps

• Mechanical sparks & friction• Rotating equipment bearing failure can lead to very hot surfaces (above the MIT)• Sliding surfaces can develop charges• Steel tools dropping onto concrete or steel• Mechanical integrity management system/vibration analysis system

• Hot work program• Open flames

• Design of heating systems & heated surfaces• Use of tools & vehicles• Maintenance

• Comfort heating equipment shall obtain combustion air from clean outside source

Damage Control

• Detachment (outside or other bldg.)• Separation (distance within same room)• Segregation (barrier)• Pressure resistant construction• Pressure relieving construction• Pressure Venting• Relief valves• Maintenance• Specialized detection systems• Specialized suppression systems• Explosion prevention systems• Maintenance

Safety and Health Information Bulletin

• Purpose• Background• Elements of a Dust Explosion• Facility Dust Hazard Assessment• Dust Control• Ignition Control• Damage Control• Training• References

Resources and Questions?

• NFPA 2-day Combustible Dust Seminar

• Combustible Dust Guidebook - NFPA

• OSHA SHIB

• www.csb.gov

• LinkedIn Combustible Dust Forums

• Facebook Grain Mill Accident page

Contact

• John Newquist

• Facebook

• LinkedIn

• Johnanewquist

• Twitter

• Email Johnanewquist@gmail.com

• Cell (815) 354-6853

Sample citations follow

2011• 5(a)(1) Hammond DusKolector, model DK- 8, dry-type dust collector,

which collected combustible aluminum dust generated by the polishing of aluminum tubing on equipment

• (1) The employer had the Hammond DusKolector, model DK-8, located inside the building.

• (2) This dust collector did not have deflagration venting.

• (3) This dust collector did not have any barriers or other means of protection for personnel from flash fire or shrapnel in the event of explosion.

• (4) Ribbed, flexible, non-metallic ductwork connected the Hammond sander. This ductwork would allow the combustible aluminum dust to accumulate on interior surfaces, and the non- metallic material of which the ductwork consisted would allow for the accumulation of static charges.

2011 continued• (5) This dust collector did not get emptied at least once per day.

• (6) When employees emptied the combustible aluminum dust from the dust collector, they did not mix the combustible aluminum dust with an inert material (five parts inert material to one part aluminum dust), but rather just disposed of the combustible aluminum dust in a dumpster, where the dust commingled with various other wastes.

• (7) This dry-type dust collector recycled air back into the Polishing Room. (b)Polishing Room - The facility had a dry-type dust collection system, which collected combustible stainless steel dust generated by the polishing and buffing of stainless steel tubing. This dust collection system, located outside of the building, had the following deficiencies, on or about

2011 continued• Among other methods, one feasible and acceptable abatement method to

correct this hazard includes following National Fire Protection Association NFPA 484, Standard for Combustible Metals, 2009 Edition, including, but not limited to:

• *Locate dry-type dust collectors, used to collect combustible aluminum dust, outside of buildings (NFPA 484 Chapter 6, Section 6.3.2.5).

• *Provide deflagration vents on dry collectors, used to collect combustible aluminum dust (NFPA 484, Chapter 6, Section 6.3.5.6).

• *Provide dry-type dust collectors, used to collect combustible aluminum dust, with barriers or other means for protection of personnel (NFPA 484, Chapter 6, Section 6.3.2.5.2).

• *Construct ducts on dust collection systems, used to collect combustible aluminum dust, only of conductive material fabricated and assembled with smooth interior surfaces and with internal lap joints facing the direction of airflow (NFPA 484, Chapter 6, Section 6.3.3.5.1), and also bond and ground duct systems, dust collectors, and dust-producing machinery to minimize accumulation of static electric charge (NFPA 484, Chapter 6, Section 6.3.3.6).

2011 continued• *Remove combustible aluminum dust from dry collectors at least once each

day and at more frequent intervals if conditions warrant (NFPA 484, Chapter 6, Section 6.3.5.5), and mix the combustible aluminum dust waste with an inert material in a volume ratio of five parts inert material to one part metal dust (NFPA 484, Chapter 6, Section 6.3.5.5.3).

• *Do not recycle air from dry-dust collectors, used to collect combustible aluminum dust, into buildings (NFPA 484, Chapter 6, Section 6.3.6).

• *Provide each machine that produces combustible stainless steel dust with hoods, capture devices, or enclosures connected to a dust collection system that has sufficient suction and capture velocity to collect and transport all the dust produced (NFPA 484, Chapter 12, Section 12.2.1.1).

• *Provide deflagration vents on dry collectors, used to collect combustible stainless steel dust (NFPA 484, Chapter 12, Section 12.2.10.7).

• *Provide dry-type dust collectors, used to collect combustible stainless steel dust, with barriers or other means for protection of personnel (NFPA 484, Chapter 12,Section 12.2.1.5). *Locate the blower for drawing the dust-laden air into the stainless steel dust collector on the clean-air side of the collector (NFPA 484, Chapter 12, Section 12.2.10.12).

2011 continued• *Construct ducts on dust collection systems, used to collect combustible

stainless steel dust, only of conductive material fabricated and assembled with smooth interior surfaces and with internal lap joints facing the direction of airflow (NFPA 484, Chapter 12, Section 12.2.5.6), and also bond and ground duct systems, dust collectors, and dust-producing machinery to minimize accumulation of static electric charge (NFPA 484, Chapter 12, Section 12.2.5.10).

• *Remove combustible stainless steel dust from dry collectors at least once each day and at more frequent intervals if conditions warrant (NFPA 484, Chapter 12, Section 12.2.10.6).

• *Do not recycle air from dry-dust collectors, used to collect combustible stainless steel dust, into buildings (NFPA 484, Chapter 12, Section 12.2.11).

• *Do not install automatic sprinkler systems in area where combustible metals are produced or handled (NFPA 484, Chapter 13, Section 13.3.1.1).

2013

• (5)(a)(1) American Roto-Clone dust collector located outside and used to collect aluminum dust from finishing operations.

• The dust collector lacked means of

• (1) explosion protection and

• (2) upstream ductwork was deficient, as it was: not conductive, not bonded and grounded, not as straight and short as possible and has capped ends that can accumulate aluminum dust. .

• 2014 Enforcement Case: Powderpart Inc.

• Last spring, a Woburn, Massachusetts-based 3-D printing company, Powderpart Inc., was cited by OSHA for multiple alleged violations involving combustible dust hazards, including violations of the GDC for failure to furnish employment and a place of employment “which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees.” The inspection followed a November 5, 2013 explosion and fire that inflicted third-degree burns on a company employee. Powderpart allegedly failed to eliminate known sources of potential ignition and follow pertinent instructions from equipment manufacturers, did not alert Woburn Fire Department to the workplace presence of hazardous materials, and located an employee workstation and flammable powders next to an area with explosion potential, among other alleged violations, according to OSHA. OSHA’s then acting regional administrator for New England stated, “Establishments that use metal powders in this new technology need to scrutinize their processes and take steps to prevent and protect their employees from fire and explosion hazards that arise with these materials