Objectives. NFPA Dust Specific Documents. Combustible Dust Process Hazard Safety Overview of NFPA Standards for Combustible Dusts

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1 Combustible Dust Process Hazard Safety Overview of NFPA Standards for Combustible Dusts Guy R. Colonna, PE Division Manager, NFPA Combustible Dust Symposium Detroit, MI September 20, Objectives Be able to: 1. Identify what NFPA standards apply? 2. Describe the basis for safety established by NFPA standards for combustible dust 3. List significant changes to NFPA standards 4. Describe new Committee structure for NFPA combustible dust project 2 NFPA Dust Specific Documents NFPA 654, Combustible Particulate Solids NFPA 61, Agricultural and food processing NFPA 91, Pneumatic conveying and noncombustible particulate solids NFPA 120, Coal Mines NFPA 484, Combustible metals NFPA 655, Sulfur NFPA 664, Wood processing & woodworking NFPA 850, Electric generating plants 1

NFPA 654 Application Does not apply to: NFPA 30B Aerosols NFPA 61 Agricultural and Food Products* NFPA 120 Coal Preparation Plants NFPA 484 Combustible Metals Code* NFPA 664 Wood Processing and

2 NFPA 654 Application Does not apply to: NFPA 30B Aerosols NFPA 61 Agricultural and Food Products* NFPA 120 Coal Preparation Plants NFPA 484 Combustible Metals Code* NFPA 664 Wood Processing and Woodworking* Protect Against Two Hazards Fires Flash fire hazard Threat to property Thermal exposure extremely dangerous for workers Explosions Overpressure impacts structure Primary and secondary explosions 5 NFPA Standards Form Basis for Safety 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 6 2

3 Current Requirements Document Hazard Analysis Layer Thickness Housekeeping Combustible Dust Defined? Explosion Prevention& Protection 61 N None* Y Y Y 484 Y None Y Y Y 654 Y 1/32 Y Y Y 655 N 1/32 Y Y Y 664 Y 1/8 Y Y* Y 7 Document Revision Status Standard Revision Cycle Status NFPA 61 A2012 ROP published Committee meets October 2011 prepare ROC NFPA 484 A2011 Issued July 2011 NFPA 654 A2012 ROP published Committee meets September 2011 prepare ROC NFPA 655 F2011 ROP and ROC published Issued in November NFPA 664 A2011 Issued August 2011 Common Issues Definitions Determining hazardous condition or defining hazard area Layer thickness criteria i Housekeeping Controls Safety management 9 3

4 Issues - definitions Combustible dust Particle size specification 420 micron or something greater? Dust explosion hazard Dust flash fire hazard 10 Combustible Particulate Solid Any combustible solid material, composed of distinct particles or pieces, regardless of size, shape or chemical composition. (NFPA ) 11 Combustible Dust Combustible Dust* A combustible particulate solid that presents a fire or deflagration hazard when suspended in air or other oxidizing medium over a range of concentrations, regardless of particle size or shape. [NFPA 654] 4

5 Determining Hazardous Condition Defining Hazard Area Where an explosion hazard exists Dust explosion hazard area Dust flash fire hazard area What criteria i to use? What triggers application of protective measures? Accumulated dust Formation of dust cloud within enclosure 13 Reference NFPA-654 NFPA-664 NFPA-484 NFPA-61 How much Dust is too much? OSHA Grain Std. 1/8 OSHA Dust NEP 1/32 Thickness and Caveats 75 lb/ft 3, Adjusted for Lower Bulk Density 1/8, Assumes 20 lb/ft 3 Bulk Density, adjusted for bulk density Does Not Allow Accumulation, Infers Daily Cleaning Schedule Remove Concurrently with Operations, Refers to 654; OSHA for grain handling facilities used 1/8 Current allowances are based on layer thickness 3 1/ 32" 75 lb / ft Allowable Thickness in. 3 bulk density lb / ft Layer thickness is not the primary parameter Explosible cloud mass decides the consequences Layer Thickness Criteria Dust accumulation Layer depth criterion method Surface color no longer discernible Bulk density Threshold dust mass Entrainment considerations Ease of forming dust cloud Electrical ignition considerations 15 5

6 Housekeeping Housekeeping philosophy Source of accumulations, including spills Housekeeping frequency Electrical l equipment considerations per NFPA 499 versus fire or explosion considerations Cleaning methods Hierarchy based on least likely to stir up dust cloud Tools spark-resistant requirements 16 Other Controls Building design Detached, separated, or segregated Deflagration venting Isolation upstream and downstream Equipment and structure Suppression systems PPE 17 Safety Management Provisions Hazard analysis Management of change Contractor and subcontractor practices Contractor training Incident investigation procedures 18 6

7 NFPA 654 Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate t Solids (2006 edition) Represents fundamental dust provisions 19 NFPA 654 Scope Apply to manufacturing, processing, handling Combustible particulate solids or hybrid mixtures Particle size independent Fire or explosion hazard 20 NFPA 654 Contents Chapters 1 3 Administrative 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 21 7

8 Chapter 4 General Requirements Process Hazard Analysis Examine the facility, process, and fire and explosion hazards Actual test data required to support analysis Defines the nature and extent of hazard conditions Hazard control measures Management of Change 22 Chapter 6 Facility and Systems Design Define dust hazard area Protect those areas in a facility where dust explosion hazards and dust flash fire hazards exist Segregation, Separation, or Detachment Building Construction Deflagration Venting Chapter 8 Fugitive Dust Control and Housekeeping NFPA 654 establishes the need for housekeeping program Determine the source for the dust, whether from a process, handling or conveying, or fugitive Determine rate of release and accumulation Establish frequency for cleaning 24 8

9 Dust Removal Methods NFPA 654 establishes hierarchy for cleaning methods Vacuum preferred Where not practicable, use sweeping or water wash-down Blow down using compressed air only for hard to reach areas Control ignition sources All methods avoid creating dust cloud 25 Tentative Interim Amendment Protect areas where a dust deflagration hazard exists Evaluate areas to determine if hazardous conditions exist Is accumulated dust layer depth greater than 1/64 or underlying surface not discernible? If so, is layer depth criterion exceeded? Use equation to determine allowable layer thickness using bulk density correction as appropriate TIA 06-1 Determining Dust Deflagration Hazard Dust deflagration hazard exists where: Dust clouds of hazardous concentration exist, or any of the following conditions exist for buildings or rooms less than 20,000 ft 2 in footprint area: Area of dust accumulations exceeding allowable layer depth criterion is greater than 5% of footprint area, or Total volume of dust is greater than layer depth criterion multiplied by 5% of footprint area 9

10 TIA 06-1 Determining Dust Deflagration Hazard Dust deflagration hazard exists where: Dust clouds of hazardous concentration exist, or any of the following conditions exist for buildings or rooms equal to or greater than 20,000 ft 2 in footprint area: Area of dust accumulations exceeding allowable layer depth criterion is greater than 1000 ft 2, or Total volume of dust is greater than layer depth criterion multiplied by 1000 ft 2 TIA 06-1 Hazard Determination Dust explosion hazard exists in enclosed process equipment where dust is present in sufficient quantities to rupture enclosure if suspended and ignited and means of suspension exists Protect personnel exposed to dust deflagration hazards Assess hazards in order to select proper PPE Clarified use of separation in Chapter 6 NFPA 61 Agriculture and Food Processing Applies to facilities that: Handle,,p process, store or transport dry agricultural bulk materials Manufacture and handle starch Involve seed preparation and mealhandling systems of oilseed processing plants 10

11 NFPA Edition Proposed Changes Updating and/or adding definitions Performance-based provision Annex item referencing approach found in NFPA 654 Hazard analysis Refer to equivalency paragraph in standard 31 NFPA 484 Combustible Metals Applies to operations where metal or metal alloys processed or finished Combustible metal dust (CMD) been evaluated as noncombustible requires re-evaluation whenever a change occurs NFPA Edition Key Changes Issued July 10 and effective July 30, 2011 Revise Chapter 5 to include requirement for determining dust explosion and dust flash fire hazard area Hazard analysis now required for all metal chapters Management of change (MOC) now required for all metal chapters 33 11

12 NFPA Edition Key Changes PPE requirements included for most metals Added new chapter on performance-based design Additional requirements and supplemental information on housekeeping New chapter format provides consistent numbering throughout chapters 34 NFPA 655 Sulfur Applies to the crushing, grinding, or pulverizing of sulfur Handling of sulfur u in any form Does not apply to mining of sulfur, recovery of sulfur from process streams, or transportation NFPA Edition Key Changes Determine dust explosion hazard and dust flash fire hazard conditions Introduced threshold dust mass and layer depth criterion methods Establish cleaning frequency requirements based on accumulation Establish preferred cleaning methods Included performance-based design option Added annex commentary on FIBC use 36 12

13 NFPA 664 Wood Processing and Woodworking Applies to facilities that process wood or manufacture wood products, using wood or other cellulosic fiber Applies to woodworking operations that either: Occupy areas of more than 465 m 2 (5000 ft 2 ), or Require an aggregate dust collection flow rate of more than 2549 m 3 /hr (1500 ft 3 /min) Chapter 4 General Requirements Process Analysis Management of Change Objectives Life safety Structural integrity Mission continuity Mitigation of fire spread and explosions Options performance-based or prescriptive 38 Chapter 6 Building Construction Compartmentation fire walls, fire partitions, fire barrier walls Protection of openings and penetrations Life safety and means of egress Surfaces and ledges Damage-limiting construction Dust accumulation threshold established Draft curtains 39 13

14 Chapter 7 Ignition Control Hot work Electrical systems Hot surfaces Industrial trucks Lighting Fuel-fired equipment Lightning protection Static electricity Smoking Machines and processing equipment Foreign material Friction Fans Spontaneous ignition and chemical action Propellant-actuated tools Portable electric tools 40 Chapter 8 Processes, Operations, and Special Systems Particulate conveying and dust collection Pneumatic conveying see NFPA 654 Duct system Hoods and enclosures Fans or blowers (air-moving devices) Dust collectors (air-material separators) Recycling exhaust air 41 Chapter 10 Human Element Inspection and maintenance Record retention Employee training Contractors and subcontractors Contractors and subcontractors Portable appliances Incident investigation Impairments of fire protection systems Hot work Emergency planning and response 42 14

15 Chapter 11 Housekeeping Vacuuming is preferred Sweeping or water wash down is acceptable Vigorous sweeping can generate dust cloud Blowing down with steam or compressed air least preferable After other methods used and only to access hard-to-reach areas Limits on air pressure Shut down other operations if ignition source 43 NFPA Edition Key Changes New and revised definitions Determination of allowable dust layer thickness for mass accumulation Similar layer depth criterion method to NFPA 654 Define conditions necessary for dust flash fire or dust explosion hazard to exist Issued August 11 and effective August 31, NFPA 850, Recommended Practice for Fire Protection for Electric Generating Plants and High Voltage Direct Current Converter Stations Chapter 7 addresses coal handling Storage Bins, bunkers and silos Dust suppression and control Coal conveyors Coal conveying and handling structures Fire protection 45 15

16 Additional References NFPA 68, Standard for Explosion Protection by Deflagration Venting, 2007 NFPA 69, Standard on Explosion Prevention Systems, 2008 NFPA 91, Standard for Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Noncombustible Particulate Solids, 2010 New Committee Structure Per Standards Council decision March 2011, new committee structure approved Technical Correlating Committee Technical Committee on Fundamentals of Combustible Dusts CMD-FUN startup roster approved August 9, 2011 CMD-AAC roster pending October meeting of Standards Council 47 Accessing NFPA Document Information Pages Home page Codes and Standards tab List of documents From web browser Next edition tab 48 16

17 49 Combustible Dust Process Hazard Safety Overview of NFPA Standards for Combustible Dusts Guy R. Colonna, PE Division Manager, NFPA Combustible Dust Symposium Detroit, MI September 20,

Combustible Dust Hazard Recognition and Control NFPA Standards for Combustible Dusts

Combustible Dust Hazard Recognition and Control NFPA Standards for Combustible Dusts Guy R. Colonna, PE Division Manager, NFPA Pellet Fuels Institute Conference Asheville, NC July 20, 2010 1 Objectives