Download presentation
Presentation is loading. Please wait.
1
Combustible Dust Handling Risks
2
Timber Products Manufacturers
Purpose The following will be discussed: Hazard characteristics and behavior of Combustible dusts. How to perform risk assessments to recognize hazards associated with combustible dusts, and Suggested Control Methods. Timber Products Manufacturers
3
Timber Products Manufacturers
Objectives Define combustible dust and its impact on industry Mention loss statistics due to dust explosions Identify risk areas Discuss available controls Identify applicable associated standards Briefly introduce the proposed regulation Timber Products Manufacturers
4
Timber Products Manufacturers
Topics to be discussed Historical background Definitions Related risks Facility evaluation Controls Prevention Mitigation 6. Training 7. Proposed Rule 8. References Timber Products Manufacturers
5
HISTORICAL BACKGROUND
Since 1980 there have been over 280 combustible dust explosions, according to a study by The Chemical Safety Board (CSB). The result has been a total of 133 deaths and more than 730 wounded. Most of the workers or their employers do not recognize the hidden dangers of combustible dust in general industry operations. Industrial Explosions Timber Products Manufacturers
6
Are These Materials Explosive?
sugar metal coal All these materials have the potential to become combustible dust if reduced to a very fine size and if the other conditions necessary to create an explosion are present (see p. 29) plastic medicines wood Timber Products Manufacturers
7
Imperial Sugar Company
February 7, 2008 Port Wentworth, Georgia 14 deaths and numerous persons injured A spark started the fire and explosion of the sugar cloud The sugar processing plant, 91 years old, was located near the city of Savannah, and processed granulated and powdered sugar. Investigation of the Chemical Safety Board revealed that the initial explosion occurred in a bucket elevator. It is assumed that the silo operations created a buildup of combustible sugar dust suspended on horizontal work surfaces generating the first explosion. The primary explosion generated a fire, caused the partial collapse of the four floor building, and also spread more dust into the atmosphere. The airborne dust generated a series of secondary explosions that advanced rapidly throughout the gallery of the silo and the tunnel. The fire of secondary explosions in turn affect the packing facility, and the inside of adjacent buildings. Timber Products Manufacturers
8
Fire and Explosion by Metal Powder : Indiana
October 23, 2003 Huntington, Indiana 1 dead, 6 injured Aluminum powder caught fire in a dust collector, from there the flame spread and generated the explosion A disastrous explosion and fire occurred in a cast aluminum automotive parts in Indiana with the consequence one dead and six wounded. The investigation determined that the event's primary explosion occurred because of dust in or near a smelter of aluminum pieces. This was followed by a secondary explosion in the dust collection equipment, causing a fire of great proportions. Timber Products Manufacturers 8
9
Fire and Explosion in “CTA Acoustics”
February 20, 2003 Corbin, Kentucky 7deaths, several injured A poorly worked oven lit a cloud of phenolic resin dust, causing the explosion. A common work practice in this plant was to use compressed air, electric fans and brooms to remove dust from the day's operations. This generated a dust cloud in the vicinity of the furnace of the production line. It was also common to see small fires ignite by the accumulation of combustible dust near the oven, which operators put out with fire extinguishers or hoses. The day of the accident the furnace was not working properly, the door was open, allowing contact with dust and there were no employees on hand to contain the fire. The first blast of dust and fire triggered secondary explosions in several production lines, which destroyed much of the production area. Timber Products Manufacturers 9
10
Timber Products Manufacturers
West Pharmaceutical January 29, 2003 Kingston, North Carolina 6 deaths, 38 injured Phenolic resin dust accumulation enabling false ceiling fire and dust explosion The investigation of this case identified the false ceiling spaces as hazardous areas where dust can accumulate and usually pass undetected. Phenolic resins are commonly used as finishes for materials such as paper, fiberglass or cotton, which will be used to create molds or work surfaces for applications in art, electronics, textiles and others. Timber Products Manufacturers 10
11
Fire and Explosion in Malden Mills
December 11, 1995 Methuen, Massachusetts 37 workers injured Destruction of the polar fabric manufacturing company (nylon fibers) According to the research, the first event was probably an explosion of powder containing polar nylon fibers. Although there had been minor incidents of fire with nylon fibers, managers and employees in general did not know that the fibers were a risk of explosion, before this event. Timber Products Manufacturers 11
12
Timber Products Manufacturers
Grain Handling During the 70s there were several explosions in grain silos. This led to implement a specific OSHA standard , for that industry, which has significantly reduced the explosions in this industry. The experience of the grain handling industry helps to illustrate the nature of the combustible dust problem and some possible solutions. Timber Products Manufacturers 12
13
Timber Products Manufacturers
Definitions IMPORTANT CONCEPTS Timber Products Manufacturers
14
Timber Products Manufacturers
Definitions Combustible dust: Very small particles (<420 microns) that when dispersed in air have the ability to ignite under certain conditions. The NFPA 654 (2006) defines combustible dust as a particulate solid that presents a fire hazard or deflagration when suspended in air (or other oxidant) at various concentrations independent of size or shape. Combustible dusts with a particle size less than 420 microns are considered by most reference sources as explosives. For example, the particle size of flour is around 100 microns. Size Pellets (wood) > 2mm diameter Granules between 0.42mm - 2mm Dust Particulate < 0.42mm (420ųm) Pellet is commonly used to designate a solid material compacted as a small cylinder of approximately 2 mm of diameter. A solid particulate of .42 mm o 420 microns (cubic or spherical) is believed to be big enough to remain suspended in air for a considerable amount of time. This particulate size can pass through a #40 standard sieve. IMPORTANT: solid particulate or oblong flakes not passing though a #40 standard sieve can still be considered a hazard if they behave like a spherical solid particulate Timber Products Manufacturers
15
Combustible Solid Particulate
Any combustible solid material composed of particles or different pieces independent of the size, shape or chemical composition Includes: Dust Fines (coal dust) Fibers Flakes Fragments Bits Mixture of any of the foregoing pellet The easiness of ignition and the seriousness of the combustible dust explosion are usually influenced by particle size. Finer particles tend to be more explosive because they have more superficial area in relation to their mass, which permits a rapid reaction with oxygen when dispersed in air, helping spread the explosion. Timber Products Manufacturers
16
Particle Size of Common Materials
Size (microns) Salt 100 Granulated white sugar Sand 50+ Talc, Dust (baby) 10 Mold Spores 10 – 30 Human Hair Flour The table shows the different size of common particles. Source: OSHA Filtercorp International Ltd. Timber Products Manufacturers
17
Combustible Dust Fires and Explosions
Fire Triangle Fire is a chemical reaction that generates energy as light and heat. For fire to ignite it requires three elements: fuel (combustible dust), ignition source (spark), and the oxidant agent (oxygen, air ). Timber Products Manufacturers
18
Fires and Explosions of Combustible Dust
For a combustible dust explosion to happen, it requires the presence of all these factors Ignition Source Fuel (dust) Oxidant Confinement Dispersion An explosion can occur after the initial fire, for this to happen two additional elements, besides those of fire, need to be present : dust dispersion (movement of enough solid particulate to create a dust cloud) and confinement (enclose within a space or equipment). Adding these two elements to the fire triangle creates what is known as the dust explosion pentagon. Be sure to define the following: 1. EXPLOSION – The burst or rupture of an enclosure or container due to pressure buildup caused by a deflagration. Explosions within work areas are produced as the result of dust accumulation in areas generating fine dust when combustible solid particulates are produced, processed, handled or transported . it should be expected that all combustible solid particulates generate o contain combustible dust. Timber Products Manufacturers
19
Timber Products Manufacturers
Dispersion It is the effect of moving the cloud of dust from one place to another, may it be by mechanical processes (transport, ventilation, vibration, improper cleaning) or as the result of a primary explosion. Timber Products Manufacturers
20
Timber Products Manufacturers
Confinement Occurs when the fire occurs in a confined space, where the rapid change in temperature causes a rapid change in pressure. This change in pressure shock wave can be more or less destructive depending on the magnitude of the explosion and how the structure is closed The confinement does not necessarily mean that the space or equipment is completely closed, but it rather refers to the resistance or barrier provided to the free movement of the pressure wave. Timber Products Manufacturers
21
Timber Products Manufacturers
Deflagration It occurs when the combustion zone advances a velocity slower than the speed of sound, quickly producing great amounts of heat. The generated heat induces quick expansion of air and other gases freeing a great amount of pressure which can result in structural damages or injuries to workers. In the deflagration the flame advances as the material is consumed creating a fire front, with pressure changes Timber Products Manufacturers
22
Timber Products Manufacturers
Detonation The combustion speed advances faster than the speed of sound generating an audible event. Difficult to control once it has begun The speed of sound is the speed by which sound travels in an elastic medium (air, fluid). In dry 20 °C (68 °F), the speed of sound is 343 meters per second (1,125 ft/s). Timber Products Manufacturers
23
Minimum Explosive Concentration (MEC)
The minimum amount of dust suspended in air that will support deflagration. It is estimated that this concentration (MEC) can reduce the visibility of a 25 watt bulb in a room to only 6 feet of distance There are factors that determine dust explosivity: solid particulate size, humidity content of the solid particulate, ambient humidity, available oxygen for combustion, solid particulate shape and concentration (minimum explosive concentration, “MEC”). This dust concentration level is usually found in ducts, dusts collectors or process equipment. That concentration will be present when the material accumulated in work surfaces is dispersed in air due to an explosion. Thus, housekeeping is a critical factor in explosion prevention. 6 feet = 2 meters Combustible dust concentration suspended in air > MEC 25 watts Timber Products Manufacturers
24
Minimum Explosive Concentration (MEC)
Minimum Explosible Concentration. Minimum explosible concentration (MEC) of the sample is determined by suspending the sample in a 20-liter explosibility testing chamber and ignited with a 2500 joule chemical igniter. MEC is the lower concentration limit of explosibility for the dust. This limit is determined using test material that has been sieved through a 40 mesh sieve (425 µm particle size), dried, suspended in a 20-liter explosibility testing chamber. Approximately 200 grams of material with a particle size of 425 µm or less are needed for the MEC tests. There are factors that determine dust explosivity: solid particulate size, humidity content of the solid particulate, ambient humidity, available oxygen for combustion, solid particulate shape and concentration (minimum explosive concentration, “MEC”). This dust concentration level is usually found in ducts, dusts collectors or process equipment. That concentration will be present when the material accumulated in work surfaces is dispersed in air due to an explosion. Thus, housekeeping is a critical factor in explosion prevention. Timber Products Manufacturers
25
Minimum Explosive Concentration (MEC)
Some analytical details include: Use test material that has been sieved through 40-mesh screen. Use material which has been either dried in an oven at 75ºC overnight (if the moisture content is greater than 5%) or kept in a desiccator. Use 2500 J igniters. Plot both the dp/dt and pressure ratio verses concentration. The minimum explosible concentration is where the Kst is greater than or equal to 1.5 and the pressure ratio is greater than or equal to 2. There are factors that determine dust explosivity: solid particulate size, humidity content of the solid particulate, ambient humidity, available oxygen for combustion, solid particulate shape and concentration (minimum explosive concentration, “MEC”). This dust concentration level is usually found in ducts, dusts collectors or process equipment. That concentration will be present when the material accumulated in work surfaces is dispersed in air due to an explosion. Thus, housekeeping is a critical factor in explosion prevention. Timber Products Manufacturers
26
Minimum Explosive Concentration (MEC)
There are factors that determine dust explosivity: solid particulate size, humidity content of the solid particulate, ambient humidity, available oxygen for combustion, solid particulate shape and concentration (minimum explosive concentration, “MEC”). This dust concentration level is usually found in ducts, dusts collectors or process equipment. That concentration will be present when the material accumulated in work surfaces is dispersed in air due to an explosion. Thus, housekeeping is a critical factor in explosion prevention. Timber Products Manufacturers
27
Timber Products Manufacturers
Explosion Results from the combination of these factors: fire dispersion of solid particulate material in a more or less enclosed space If one of the elements of the Pentagon is eliminated the explosion will not occur. Two of the elements in the pentagon are dificult to eliminate: the oxidant agent (air), and the confinement of the dust cloud (inside processes or buildings). Nevertheless, the other three elements of the pentagon, dust, dispersion and ignition sources, can be controlled. An initial or primary dust explosion can lead to one or more secondary dust explosions. This can happen when the initial dust explosion occurring inside process or emission control equipment ignites combustible dust in nearby areas. A secondary explosion occurs when accumulated dust on work surfaces or floors is ignited as the result of the first explosion. The expansive wave from this explosion can cause the ignition of fugitive dust from nearby areas Explosion confinement fire dispersion + = + Timber Products Manufacturers
28
Timber Products Manufacturers
Primary Explosion from dust in equipment Dust Colector This slide illustrates a dust explosion inside the equipment. The dust collector is essentially constructed to conatian a pressurizationo event until it can be vented safely to a relief point or through an engineering ventialtion control. It is designed and calculated for the type of event tahas might occur inside. The result wil be a falme front like a stream that will vent through the dust collector relief point . The worker shown here is out of the danger zone. Timber Products Manufacturers Fuente: Curso 7120 OSHA Training Center
29
Secondary Explosion Mechanism
Dust accumulates on work surfaces An event disperses dust creating a cloud The cloud ignites and explodes
30
Timber Products Manufacturers
Dust Collector This slide illustrates a dust explosion inside the equipment. The dust collector is essentially constructed to contain a pressurization event until it can be vented safely. Nevertheless, nearby areas to the vent relief point, have significant amounts of fugitive dust accumulation, allowing the flame front to reach more dust and generating a secondary explosion. Expansive Wave Secondary Explosión from dust in area Dust Accumulation (on floor and surfaces) Timber Products Manufacturers Fuente: Curso 7120 OSHA Training Center
31
Timber Products Manufacturers
Who IS at risk? INDUSTRIES Timber Products Manufacturers
32
Industries that Generate or Handle Combustible Dusts
Metalworking Textiles Pharmaceutical products Forest Products Food Wastewater Treatment (used) Paper products Recycling of metal, paper, plastic Wood products Agriculture Coal Chemical Manufacturing Timber Products Manufacturers 32
33
Timber Products Manufacturers
Metal Powders Aluminum Iron Carbonile Zinc Bronze Magnesium Timber Products Manufacturers
34
Plastic Powder/ rubber
Molded Cellulose Polyethylene Melamine and its resin Polypropylene Polyacrylamide Epoxy or phenolic resin Plastics and rubber have their base on large (poly)specific molecules chains of specific molecules (ethylene, propylene, etc. Polyethylene) Polyethylene - plastic most commonly used, has several formulations and their uses range from hip replacements to covered elastic. HDPE (high density) - used for packaging juice, milk and other foods, also in toys. LDPE (low density) used in plastic bags and rigid containers Melamina y su resina – usado en la producción de textiles, adhesivos y fibras resistentes a fuego Polipropileno – algunas aplicaciones incluyen empaque, textiles (sogas, ropa termal, alfombras), papelería, piezas plásticas y envases reusables, equipo de laboratorio, componentes de automóviles y otros. Poliacrilamida – coagulante en el tratamiento de aguas usadas y en la industria de papel. También usado en la producción de lentes de contacto Timber Products Manufacturers
35
Timber Products Manufacturers
Food Cotton Coconut shell Rice starch, corn, wheat Spice powder Potato starch Sugar Coffee Cocoa powder Timber Products Manufacturers
36
Timber Products Manufacturers
Food Rice flour, oats, corn, potato, wheat Lime Walnut powder Soybean powder Seeds of raw cassava Sunflower SeedsTomatoe Carrot Timber Products Manufacturers
37
Timber Products Manufacturers
Chemicals Sodium stearate Ascorbic Acid Carboxymethyl Cellulose Lactose Calcium Acetate Methylcellulose Dextrin They are used as raw material for everyday products Ascorbic acid is known as vitamin C Methylcellulose gives consistency to shampoos, toothpaste and food products (ice cream) The sodium stearate is the basis of solid deodorants, some rubber, latex paints and inks. Dextrin has many uses, if it is yellow is used for adhesives / glues. If it is white as a food additive, textile treatment, medicines and binding agent in paper. Timber Products Manufacturers
38
Powders Containing Carbon (Carbonaceous powders)
Cellulose paste Pine soot Activated charcoal Petroleum Black charcoal Celullose Bituminous coal Lignin Petroleum coke Dry chemical Wood charcoal Timber Products Manufacturers
39
Agricultural Products
Rice starch Celullose Dry powdered milk Wheat starch Egg white Barley Lactose The majority of natural and synthetic organic materials and some metals, can form combustible dust. Timber Products Manufacturers 39
40
Timber Products Manufacturers
Risk Analysis Area Assessment Timber Products Manufacturers
41
Risks Factors What factors should I consider for preventing explosion?
Major Factors: Dust Combustibility The accumulation of dust in areas and work surfaces Presence of ignition sources. Timber Products Manufacturers
42
Combustibility Determination
The first step in the risk analysis should be to determine if the powder is combustible To determine whether an explosion may occur in a facility, we must conduct a risk analysis for the powder. The main thing to determine in this analysis is whether the dust is actually combustible. To do this you need to know if a cloud of dust studied detonated, deflagrate, or if you have any fire hazard. This information can be located in the data provided by the manufacturer or by a specific flammability test (see ASTM) Timber Products Manufacturers
43
Powder Combustibility
Verify if the presence of dust increases the risk of fire, explosion and / or a detonation within the workspace. In some cases it will be determined by an specific flammability test. Consider: Particle size and shape Relative humidity and oxygen present in the environment Minimum explosive dust concentration (MEC). It is believed that fine particles or smaller can play an important role in the ignition of dust clouds and hence, on the spread of the explosion. As more small particles there are in a determine space, larger surface area will be available for combustion. The smaller the particle, the easier it is warming up to the ignition temperature of the substance. Timber Products Manufacturers 43
44
Timber Products Manufacturers
Accumulation Open Areas Production Packaging Process Horizontal surfaces Floors Hidden Areas Beams False Ceilings Ducts Piping Powder Dispersion Mechanic Vibration Ventilation Sweep Cleaning Dust accumulation may occur in open areas such as work surfaces or floors or hidden areas on beams and false ceilings where is not possible to observe the build-up easily. Dust dispersion rarely occurs as a result of natural ventilation in most cases using a mechanical device or cleaning equipment caused the movement of dust Timber Products Manufacturers
45
Timber Products Manufacturers
Ignition Sources Vehicles Process Equipment Illumination Hot Surfaces Cleaning Any potential ignition source present in the work area can supply the energy needed to start the fire and / or explosion. Vehicles - forklift must be rated for use in Class II areas, typically are electric or of internal gas with specials covers on the engine or emission to prevent sparks. Process equipment - should be grounded or have the appropriate device driver or dissipate static charges. They should not have any mechanical sparks hot surfaces without proper protection systems. The lamp must meet electrical code requirements (NEC, NEMA). The mechanical equipment such as vacuum cleaning has to be type approved for use in Class II electrical classification. Timber Products Manufacturers
46
Timber Products Manufacturers
Contributing Factors Materials (dust type) Equipment (Electrical class) Processes (use, produce, consume) Areas (open, hidden) Ignition sources (present) Dispersion (dust movement) Actually there are several elements to take into account when assessing an installation to determine if there is a fire hazard or combustible dust explosion. This chart summarizes these factors: Materials that can be combustible when particle size is reduce Processes that: use (cleaning processes) consumed (as part of its raw material) or produce combustible dusts Equipments on which dust can concentrate or are not appropriate for the electrical rating of the area: Open areas where combustible dust may accumulate Hidden areas where combustible dust may accumulate Means by which dust can be dispersed in the air, and Potential sources of ignition. EXPLOSION Timber Products Manufacturers
47
Other Considerations in Risk Analysis
Must assess the electrical ratings of the areas Consider the scenario in which dust may be generated as a result of equipment failure or operating procedures Risk analysis should include evaluation of the electrical classifications. A detailed analysis that considers all possible scenarios that can generate dust is recommended, taking as reference the corresponding electrical code. They have tried to use some subjective rules to establish a relationship between the electrical rating and frequency of cleaning is recommended that you begin cleaning immediately: When you can write on the dust. If dust obscures the surface color - provided by the metal powder. If dust accumulation reaches the dimensions given in Table A of NFPA 654 Quantity Accumulation frequency Cleaning frequency elect. Classification. Negligible Almost none N/A None – gen. use Up to 1/32” Less frequent, Less during None – gen use no more than 2-3 times per year -per shift - Up to 1/32” Frequent(>3 time/year) Clean as needed None – covered Continuous – < a 1/32” /24 hr to mantain 1/64” NEMA12, sealed From 1/32” a 1/8” Less frequent clean during None – covered (2 coins) per shift NEMA 12, sealed From 1/32” a 1/8” Frequent to continous Clean as necessary Class III to keep 1/64” division 2 Greater at 1/8” Les frequent Stop and clean Class II immediately division 2 Greater than ¼” Continue to frequent Class II, Division 1 Timber Products Manufacturers Fuente: Curso 7120 OSHA Training Center
48
Timber Products Manufacturers
Hazards Analysis Determine if a combustible dust is potentially dangerous in a work area Look for accumulations of fine dust Find ways in which the powders are dispersed in the air Possible sources of ignition Consider dust collectors, hoppers and other equipment that can confine a cloud of dust. Investigate possible ignition sources Look for: processes that use, consume or produce fine powders. accumulations of fine dust, even in hidden areas (such as inside air conditioning ducts or suspended ceilings (acoustic)). Timber Products Manufacturers
49
Principal Methods of Control
Prevention & Mitigation Timber Products Manufacturers
50
Principal Methods of Control
Both OSHA and NFPA established that the best way to prevent the combustible dust hazard is using engineering controls such as; Design of pipes and equipment capable of containing the dust or a dust explosion safely Reduction of work surfaces where dust can accumulate Control of ignition sources We must establish a program of regular cleaning frequencies for floors and horizontal surfaces, such as ducts, pipes, hoods, attic and rafters to minimize dust accumulation within areas of operation. Work surfaces should be designed to minimize dust accumulation and facilitate cleaning. Timber Products Manufacturers
51
Principal Methods of Control
Control methods are: Prevention of fire and explosion, this means, to prevent it from happening either of these situations by; Dust accumulation control Ignition sources control Reduction in the concentration of oxidant (NFPA 69 Chap.7) Timber Products Manufacturers
52
Principal Methods of Control
Mitigation of damage, once the fire or explosion process occurs, keep damages to a minimum by: Systems of ignition detection and control Containment pressure deflagration Deflagration Suppression Isolation Timber Products Manufacturers
53
Principal Methods of Control
Administratives Establish a cleaning program with regular frequencies Good work practices Personal Protective Equipment Equipment classified as fire resistant (FR) Timber Products Manufacturers 53
54
Prevention – Dust Control
NFPA 654 recommends: Minimize the relelease of fugitive dust that comes from process equipment or ventilation systems Use dust collection systems Use work surfaces that reduce dust accumulation and facilitate cleaning NFPA provides general recommendations for prevention and damage control that can be adapted to any industry The spots are traces of dust Timber Products Manufacturers Fuente: Curso 7120 OSHA Training Center
55
Prevention – Dust control
NFPA Code 654 – Inspect and clean dust residues at regular intervals in open and hidden areas Hidden areas should have access for inspection, if not must be sealed Timber Products Manufacturers
56
Prevention – Dust Control
NFPA code 654 Use cleaning methods that do not generate dust clouds; Only use vacuum cleaners approved for combustible dust collection Only use vacuum cleaners approved for dust collection in areas classified as Class II Timber Products Manufacturers
57
Prevention – Ignition Control
NFPA Code 654 Consider all sources of ignition from: Electrical systems and lighting equipment Static electricity, including grounding connection of equipment; Flame and sparks control; No! Use the following ignition controls; Using methods of wiring and electrical equipment suitable for the area. Control of static electricity, including grounding the equipment. Smoking Control, flames and sparks Timber Products Manufacturers Fuente: Curso 7120 OSHA Training Center
58
Prevention – Ignition Control
NFPA Code 654 Sparks and friction mechanical control to remove foreign materials that can cause fires in combustible materials of the process; Separate combustible dust from hot surfaces and equipment that generate heat Have hot work permits available Timber Products Manufacturers
59
Magnets operating position Timber Products Manufacturers
Magnetic Separator Hopper Magnets operating position You can use permanent magnets or electromagnets with failure indicators to warn of unwanted material. This slide illustrates the need for periodic inspection and cleaning. Timber Products Manufacturers
60
Prevention – Ignition Control
Other ignition sources OSHA 29 CFR (c) regulates powered industrial trucks on dust areas The coal handling operations must meet the electrical requirements specified in OSHA 29 CFR The establishes the recommended powered industrial trucks categories for areas classified as Class II The is more properly directed to the requirements in distribution or electrical generation areas from different sources in this case coal. Class II Group E,F,G Timber Products Manufacturers
61
Prevention – Ignition Control
NFPA Code 654 The manual loading of material from intermediate bulk containers is not allowed, when the movement of dust may cause a flammable atmosphere. Tank with flammable mixture Dust No! The transfer of combustible dust from intermediate bulk containers (IBC) can cause static ignition hazard. NFPA 654 discusses the various types of IBC and the risk of ignition of the powder for each type of IBC. As more conductivity is associated with a IBC, reduces the risk of ignition. Manual additions through a hatch or lid to a container containing flammable vapors are allowed in batches of 50 lbs. or less. The lower amount of product reduces the risk of a fireball that involves workers. Timber Products Manufacturers
62
Mitigation – Damage Control
Are methods used to control and reduce the severity of an explosion or fire. Combustion Detection and Ignition control Spark and ember detection Gas sensors Optical sensors Deflagration Suppression Detects changes in pressure Activates discharge suppressor material to stop the flame propagation Some methods of control and risk reduction involves the separation of the hazard (isolation distance) or segregation of the hazard (isolate with a barrier). These and / or other methods listed on this slide can fit into engineering solutions carefully planned. Timber Products Manufacturers
63
Mitigation – Damage Control
Are methods used to control and reduce the severity of an explosion or fire. Containment of pressure / deflagration Provides cover or structure able to contain the pressure generated in the deflagration Is not useful for detonation Isolation Seperation - isolated by distance Segregation - isolating chemical or physical barrier Timber Products Manufacturers
64
Timber Products Manufacturers
Requirements TRAINING Timber Products Manufacturers
65
Timber Products Manufacturers
Training Personnel working in areas at risk of explosion or fire from combustible dust must be trained at least: Hazard Communication on combustible dusts Engineering control methods such as detection, suppression and extinguishing Timber Products Manufacturers 65 65
66
Timber Products Manufacturers
Training Workers must be trained on: Equipment and systems preventive maintenance Considerations as the electrical classification of the area Emergency plans Timber Products Manufacturers 66 66
67
Timber Products Manufacturers
New ProposeD Rule Standard Combustible Dust Combustible Dust Explosion and Fire Prevention Act of 2008 (Introduced in House HR 5522 IH 110th CONGRESS 2d Session Timber Products Manufacturers
68
The U.S. Chemical Safety Board
Conducted a comprehensive study of dust explosions and found A pattern of catastrophic explosions. The MSDS often fail to provide information on dust explosion Recommended that OSHA develop a standard. OSHA responded by establishing its National Emphasis Program (NEP) for combustible dust In 2006, the CSB issued a report recommending that OSHA regulate powders for industry in general, according to the provisions of the NFPA standards. Since that recommendation OSHA established a national emphasis program. He also began the steps to create a regulation for dust. Timber Products Manufacturers 68 68
69
Industries Inspected Under the NEP
Timber Products Manufacturers 69
70
Combustible Dust Violations
General Duty Clause Violations Housekeeping Violations Electrical Violations Timber Products Manufacturers 70
71
Timber Products Manufacturers
Other Violations Industrial Trucks (Forklifts) Hazard Communication Personal Protective Equipment Lockout/tagout Machine Guarding Exit Routes Timber Products Manufacturers 71
72
Common Findings - Housekeeping
Hazardous levels of dust in the workplace due to poor cleaning Dust accumulation depth of 1/32 of inch. Process equipment, such as windmills, air ducts, mixers and dust collectors are not designed or maintained to keep dust out of nearby areas Horizontal surfaces not minimized Timber Products Manufacturers 72
73
Common Findings - Electrical
Using electrical equipment and vacuum cleaners not approved for locations in areas with combustible dust. Management of motor vehicles (forklifts) not authorized in areas with combustible dust Timber Products Manufacturers 73
74
Common Findings - Fire Protection
Heating equipment with open flames used in areas that generates or handle dust. Lack of preventive maintenance of mechanical equipment - creating heat and friction Perform hot work in areas where dust is handled without hot work procedures Timber Products Manufacturers 74
75
Common Findings - Explosion Control
OSHA has announced it will issue a citation for the presence of combustible dust under this standard if dust accumulations exceed 1/32-inch deep, cover at least 5% of a room’s total area or 1,000 square feet, and are combustible. Dust that has accumulated to a depth of 1/32 inch is about the thickness of a standard paper clip. Timber Products Manufacturers 75
76
Common Findings - Explosion Control
Dust accumulations inside dust collection systems, containers, or mixers are not subject to this standard, but may be subject to OSHA’s general duty clause NFPA standards for specific substances, such as wood dust (1/8 inch) Before an OSHA inspector arrives, an employer should ensure that someone in the company understands the integral parts of the company’s dust collection system enough to explain to OSHA inspectors what precautions are in place. Timber Products Manufacturers 76
77
Common Findings– Explosion Control
Lack of ventilation and supression systems on hoppers, silos, bucket elevators, and dust collectors. Equipments with dust bag located inside the buildings without appropriate systems for explosion protection. Explosion releasing directly to work areas instead of outwards Timber Products Manufacturers 77
78
Timber Products Manufacturers
Proposed Rule These findings and the studies conducted by the Chemical Safety Board have resulted in OSHA decision to start the process to adopt a rule for the handling of combustible dust in the General Industry Originally known as the Congress project HR5522. Timber Products Manufacturers 78
79
Timber Products Manufacturers
Proposed Rule Standard is expected to discuss issues such as : Definitions Methods of hazard evaluation Methods of hazard control Interaction with the Hazard Communication Standard Trainings Emergency rescue plan, etc. Timber Products Manufacturers 79
80
Timber Products Manufacturers
Applicable Standards Timber Products Manufacturers
81
Timber Products Manufacturers
Applicable Standards Existing OSHA Standards: – Housekeeping – Emergency Action Plans – Ventilation – Process Safety Management – Generation of Electrical Energy Grain Handling Facilities Timber Products Manufacturers 81
82
Timber Products Manufacturers
Applicable Standards Existing OSHA Standards (cont.) Hazardous locations, Hazard Communication Section 5 (a) (1) – General Duty Clause ANSI and NFPA Applicable standards Timber Products Manufacturers 82
83
Timber Products Manufacturers
References OSHA 29 CFR 1910 – Applicable standards NFPA 654 – Prevention of Fire and Dust Explosions from Manufacturing, Processing and Handling of Solid Combustible Particle. NFPA 499 – Combustible Dust Classification, and Hazardous Locations. NFPA 61 – Agricultural and Food Processing Facilities NFPA 69 – Explosion Prevention Systems CSB – Chemical Safety Board, publications Timber Products Manufacturers
84
Timber Products Manufacturers Association
Safety Consultation Safety Audits Safety Training OSHA Citation Consultation Creating Safety Programs & Manuals Industrial Hygiene – Noise & Chemical exposures…. Ergonomics – Work Evaluations and Procedures Employment Law & Human Resources Employee Benefits Health Insurance Retirement 401K Timber Products Manufacturers
85
Timber Products Manufacturers
END Timber Products Manufacturers
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.