External Webinar - What to Know Before Completing a Dust ......equipment explosion, dust explosion...
Transcript of External Webinar - What to Know Before Completing a Dust ......equipment explosion, dust explosion...
What to Know Before Completing a Dust Hazard Assessment
Principal Engineer – BakerRisk, San Antonio Has performed over 200 dust hazard analyses as well as numerous incident investigations across a
wide range of industries all over the world. Committee member of:
NFPA 652 “Standard on the Fundamentals of Combustible Dust.” NFPA 654 “Standard for Prevention of Fire and Dust Explosions from the Manufacturing,
Processing, and Handling of Combustible Particulate Solids,” NFPA 61 “Standard for the Prevention of Fires and Dust Explosions in Agricultural and Food
Processing Facilities”www.BakerRisk.com
Presenter: Phil Parsons
Copyright BakerRisk. All rights reserved.
Dust Hazard Assessment Webinar, February 2021 2
Presenter: Phil ParsonsPrincipal Engineer, BakerRisk
What to Know Before Completinga Dust Hazard Assessment
February 9, 2021Copyright BakerRisk. All rights reserved.
Dust Hazard Assessment Webinar, February 2021
Notable Losses
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Housekeeping
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How Dust Explosions Occur
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Codes and Standards
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Common Deficiencies
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Dust Hazard Analysis
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Overview
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Imperial Sugar Company
Port Wentworth, GA
14 fatalities
Numerous injuries
Imperial Sugar (2008)
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Didion Milling (2017)
Didion Milling
Cambria, WI
5 fatalities
14 injuries
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Slow Combustion Faster Combustion
Deflagration(Explosion if Contained)
Source: Dust Explosions in the Process Industries, Second Edition, Rolf K Eckhoff
How Dust Explosions Occur (1 of 5)
• If it can burn, its dust is probably a combustible dust
• Combustion rate increases with subdivision of material
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How Dust Explosions Occur (2 of 5)
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• Damage generally limited to enclosure in which explosion occurs, with potential for heavy damage to adjoined structures
• High potential for burn injuries in vicinity of dust explosion
How Dust Explosions Occur (3 of 5)
Testing Completed by BakerRisk
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• Catastrophic dust explosions are generally secondary dust explosionso Primary explosion occurs (e.g., gas fired
equipment explosion, dust explosion within equipment, primary dust explosion, etc.)
o Resulting blast and air motion suspends dust that had accumulated in area (primarily on elevated horizontal surfaces)
o Suspended dust ignites and explosion propagates until dust is consumed throughout enclosed area
How Dust Explosions Occur (4 of 5)
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• Significant dust explosions can also occur from “primary” explosionso Deflagrations within individual or connected equipment can result in significant consequence
unless appropriately protected
o Major focus of dust hazards analysis (DHA)
How Dust Explosions Occur (5 of 5)
Dust Hazard Assessment Webinar, February 2021
Firefighter Caught in a Vented Dust Deflagration Fireball (Photo courtesy of OSHA.gov)
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• Good housekeeping eliminates secondary explosion potential
Importance of Housekeeping (1 of 3)
o NFPA 654: manage dust accumulations <1/32-inch (0.8 mm, paper clip) over < 5% of building footprint 5% typically equivalent to surface area of
elevated horizontal surfaces Can scale allowable thickness for different
bulk densities (1/32-in based on 75 lb/ft3) BakerRisk recommends using “accumulation
obscures color of underlying paint” as criteria for cleaning
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Importance of Housekeeping (2 of 3)
Examples of problematic dust accumulations
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Importance of Housekeeping (3 of 3)
Examples of good housekeeping
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NFPA 652Standard on the Fundamentals of Combustible Dust
NFPA 61Agricultural and Food Processing Facilities
NFPA 654Manufacturing, Processing and
Handling of Combustible Particulate
Solids
NFPA 664Wood Processing and
Woodworking Facilities
NFPA 655Sulfur Fires and
Explosions
NFPA 484Combustible Metals
NFPA 499 Recommended PracticeClassification of Combustible Dusts and of Hazardous
(Classified) Locations for Electrical Installations in Chemical Process Areas
NFPA Standards
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• On October 18, 2007, OSHA published the “Combustible Dust National Emphasis Program” (NEP)o NEP describes OSHA expectations regarding owner / operator compliance with U.S. Safety
Standards
o OSHA references NFPA relevant standards for guidance on identifying and mitigating combustible dust hazards
• NEP activity has lagged over last few years due to lack of qualified inspectors
• OSHA still issuing dust-related citations based on plant inspections
• OSHA will issue dust-related citations in event of incident
US Regulatory Environment (1 of 2)
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US Regulatory Environment (2 of 2)
Top OSHA dust-related citations ………. Insufficient progress made on completing DHA by Sept 2020 Hazardous levels of dust accumulations in the workplaces due to
poor housekeeping practices Electrical equipment and Powered Industrial Trucks not approved
for locations handling combustible dusts Dust collectors located inside buildings without proper explosion
protection systems (e.g., venting or suppression) Deflagration isolation systems not provided to prevent deflagration
propagation from dust handling equipment to other parts of plant
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DHA Overview (1 of 6)
Owner/operator is responsible to ensure a DHA was completed by September 2020 (January 2022 for Ag/Food Industries)
DHA must be: Performed by a qualified person Documented, including action items / recommendations and path
forward to implement solutions. NFPA standards allow for two approaches to satisfy DHAo Prescriptive (gap analysis)o Performance based (risk)
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DHA Overview (2 of 6)
Prescriptive Approach (gap analysis) Comparison against relevant commodity-specific NFPA standard, along
with NFPA 652 Audit of operations, equipment, housekeeping, and procedures for
combustible dust fire & explosion hazards Comparison against prescriptive requirements from standards Should cover all requirements, not just the “highlights” Needs to be comprehensive to avoid false sense of security
Recommendations can be extensive Can pose challenge to address all recommendations in a timely fashion
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DHA Overview (3 of 6)
Prescriptive Approach – Example:
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DHA Overview (4 of 6)
Prescriptive approach (gap analysis)
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DHA Overview (5 of 6)
Performance-based approach (risk) Systematic approach to assess hazards and associated risk Allows for prioritization and screening of risks Can utilize same approach as in traditional PHA Employ corporate risk matrix Assess consequences and likelihood of identified scenarios Layers of Protection Analysis (LOPA) can be implemented to evaluate
integrity of associated safeguards BakerRisk uses PHA-Tool with purpose-built DHA module to conduct
performance-based studies
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DHA Overview (6 of 6)
Performance-based approach (risk)
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What’s wrong with this picture?
Deflagration Vent Panels
Exhaust Duct
Dust Collector
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What’s wrong with this picture?
Deflagration Vent Panels –acknowledges explosion hazard is credible
Dust Collector
No deflagration isolation device on the inlet!
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• Material specific explosibility data (e.g., Kst, Pmax) to support explosion system design basis Key parameters needed to ensure explosion protection system will function as intended
• If available, often not representative “As-received” vs. finest fines
Moisture content
Explosion Protection Design Deficiencies
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Design Basis Limitations
Example: Suppression System Design Details
“DURING SYSTEM ACTIVATION BY PRESSURE OR OPTICAL DEFLAGRATION DETECTION, A MOMENTARY PRESSURE EXCURSION WITHIN THE PROTECTED VOLUME NOT EXCEEDING 3.0 PSIG CAN BE EXPECTED.”
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Abort Gate Trigger
What’s wrong with this picture?
Abort Gate
Upstream Fan
Dust Collector
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What’s wrong with this picture?
Deflagration Vent Panels
Plant Manager’s Office!Dust Collector
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What’s wrong with this picture?
Product Buildup in the Duct
Fire Hazard!
• Not Achieving Minimum Flow Velocity (4,000 fpm)
• No Inspection/Clean out hatches
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What’s wrong with this picture?
Deflagration Vent Panels
Escape Route
Possible Solution - Canopy
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Deflagration Vent Panels
Roadway
Building Egress
Possible Solutions:
- Flameless Vents- Restricted Access- Canopy
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What’s wrong with this picture?
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What’s wrong with this picture?
Deflagration Vent Panel
Vent Duct to Outside
Vendor should supply proof that design basis is compliant with NFPA standards!
Dust Hazard Assessment Webinar, February 2021
Dust Hazard Assessment Webinar, February 2021
It is the owner/operator's obligation to determine whether the particulate solids handled are combustible.
Do I Handle Combustible Dust?
NFPA Standards require owner/operators perform a DHA to ensure safe operations.
Should I Perform a Dust Hazards Analysis?
Ensure someone qualified with sufficient experience to be able to identify potential combustible dust hazards participates in the DHA process.
Not All DHAs are Equal
A well-performed DHA should be able to identify hazards that may still be present even though equipment is “protected”.
Details Matter
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Closing Thoughts
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Dust Hazard Assessment Webinar, February 2021
• Hazard identification – Facilitate Explosibility Testing of Dusts
• Perform Your DHA - Evaluate and Quantify Combustible Dust Hazards
• Corporate DHA Guidance – Provide Assistance Developing DHA Strategies for Multi-Facility Organizations
• Incident Investigation – Aid with Determining Cause/Origin
How Can We Help?
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What to Know Before Completing a Dust Hazard Assessment
[email protected] 210-824-5960www.bakerrisk.com
www.BakerRisk.com
Phil Parsons
Copyright BakerRisk. All rights reserved.
Upcoming BakerRisk Webinar:What to Know Before Completing a Building Upgrade
www.BakerRisk.com
Date: April 6th, 2021Presenter: David Wood
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