Prevent secondary dust explosions and save lives and property by implementing a proactive approach that utilizes industrial vacuum cleaners.
In July 2008, OSHA proposed an $8.77 million fine against Imperial Sugar Co. for violations related to a Feb. 7, 2008 explosion at the company's refinery in Port Wentworth, Ga. This blast, which was caused when combustible sugar dust ignited, killed 13 workers and injured more than 40 others.
Since that explosion, lawmakers have urged OSHA to create a specific, dust-related standard. In the meantime, the agency has looked to standards already on its books to protect workers.
Under intense scrutiny since the U.S. Chemical Safety and Hazard Investigation Board (CSB) released its 2006 Combustible Dust Hazard Study, OSHA is taking action to amend is General Industry Housekeeping provision, 1910.22. The amendment to the housekeeping requirements comes as a result of employers' misinterpretation of housekeeping standards already included in the provision.
In a hearing before the Senate Subcommittee on Employment and Workplace Safety, Edwin G. Foulke Jr., former assistant secretary of OSHA, said the provision would “state more explicitly what has always been true: that the standard applies to accumulations of dust that contribute to an explosion hazard. This clarification of language in the Housekeeping provision will eliminate any doubt that employers are obligated to prevent combustible dust from accumulating in their workplaces.”
Although OSHA's General Industry Housekeeping provision 1910.22 does not specifically address housekeeping and fugitive dust, other OSHA standards such as the Dust Control Handbook For Minerals Processing and OSHA's Grain Handling Facilities Standard, as well as MSHA regulations for coal mines, do address fugitive dust and suggest that operations “eliminate the use of compressed air jets to clean accumulated dust from the equipment or clothing and substitute a vacuum cleaning system” and “use a vacuum cleaning system to clean spills and dust accumulations. Avoid brooms and shovels.” (The problem with using brooms and air compressors is that they just blow the dust around, resulting in small particles that settle onto elevated surfaces.)
However, there continues to be a lack of regulation regarding the handling of fugitive dust for general industry including food products, rubbers, metal, wood, pharmaceuticals, plastics, paint and coatings and synthetic organic chemicals.
VACUUM CLEANING FIRST DEFENSE
In nearly all industries, with the exception of the metals industry, the NFPA recommends vacuum cleaning as the preferred first defense method of controlling fugitive dust. NFPA 654 states, “Vigorous sweeping or blowing down with steam or compressed air produces dust clouds.” Specifics on NFPA standards in relation to particular industries will be covered later.
Despite the recommendations of NFPA and OSHA standards, many companies today still use air compressors and brooms to clean surrounding equipment and areas of dust and debris. This may be due to the misconception about industrial vacuum cleaners and sheer oversight when reviewing production processes. When a process has been in place for decades, it becomes somewhat transparent and the standard, ‘if it ain't broke, don't fix it,’ often prevails.
In an effort to bring a greater awareness to the severity of poor housekeeping methods, OSHA launched a National Awareness Program (NEP) focusing on workplaces where combustible dust hazards are likely to be found. The program lists different types of materials that can generate combustible dust.
Industries covered by the NEP include agriculture, food processing (including sugar), chemicals, textiles, forest products, metal processing, tire and rubber manufacturing, paper products, pharmaceuticals, recycling operations and coal handling and processing facilities. These industries deal with a wide range of combustible dusts, including metal dusts such as aluminum and magnesium, wood dust, coal and carbon dust, plastic dusts, biosolids, certain textile materials and organic dusts such as paper, soap, dried blood and sugar.
Although using vacuums isn't new to these industries, many companies in the past have tried to use shop-type vacuums to clean up dust and debris but have found them inadequate under the rigorous demands in the processing industry. In contrast, industrial vacuums can suck up tons of material an hour; these powerful tools are not what people have at home or in their workshops.
Frank Pendleton, the founder of Vac-U-Max, developed the first air-operated industrial vacuum for use in the textile industry. First-hand experience taught him the fire hazard had to be safely and efficiently removed, and he knew the dust and lint surrounding oiled textile machinery was a time bomb ready to go off. Dissatisfied with traditional compressed air hoses that simply blew unwanted debris around and aware that existing electrical vacuums were not only underpowered but also posed a real ignition risk due to sparking on start up, Pendleton began engineering a working solution. In 1954, he introduced the first air-operated vacuum cleaner, or air vac, which was three times as strong as its electrical counterpart and posed no sparking hazard.
VITAL HOUSEKEEPING STANDARDS
Although there have been many technological advances over the last 50 years to prevent dust explosions, good housekeeping is vital. Without the accumulation of significant amounts of combustible dust, catastrophic secondary explosions will not occur.
After the Imperial Sugar refinery dust explosion, OSHA launched an intense campaign targeted at preventing additional mishaps, including distributing a fact sheet, HazardAlert: Combustible Dust Explosions, that addresses secondary explosions. According to the fact sheet, “Due to poor housekeeping practices, an initial explosion may dislodge into the air the dust that is accumulated on the floors, beams and other areas of a workplace. This dispersed dust, if ignited, may cause one or more secondary explosions. These secondary dust explosions can be far more destructive than a primary explosion due to the increased quantity and concentration of dispersed combustible dust. Many deaths in past accidents, as well as other damage, have been caused by secondary explosions.”
The Hazard Alert also references several NFPA standards that address the need for companies to employ vacuum cleaners in housekeeping practices to prevent catastrophic explosions.
After Imperial Sugar's Port Wentworth sugar refinery exploded, OSHA determined that the company willfully refused to remedy similar conditions at their Grammercy plant, resulting in more than $8.7 million of proposed penalties for both plants, the third-highest proposed penalty in OSHA's history.
The relative cost of even the most elaborate central vacuum system is minute compared to the loss of life that occurs from secondary explosions or the fines levied against a company that fails to proactively protect their workers.
Although the majority of companies aren't in willful violation of the standards, a lack of understanding of housekeeping standards and misconception of the relatively low cost of vacuum systems prevail in the industry. Often times, the addition of industrial vacuum cleaners to the housekeeping routine produces additional cost benefits in terms of increased production, reclamation or wage savings.
APPLYING HOUSEKEEPING STANDARDS
The proper selection of an industrial vacuum cleaning system is based primarily on the application. In some cases, small air and electric-powered drum- style units will suffice, while others require a central large electric and diesel powered units for multiple users and filtration systems capable of capturing particles that are invisible to the naked eye. Often, users may assume they need a custom, one-of-a-kind solution when their application actually calls for a standard, pre-engineered product.
Some applications require sophisticated customized vacuum cleaner installations. For other applications, compact, off-the-shelf vacuum systems are perfectly adequate when replacing crude or unnecessarily hazardous cleaning methods, such as the use of compressed air hoses for blowing debris.
H.R. 849 would compel OSHA to issue an interim and final combustible dust standard to help prevent deadly explosions. Many proponents want OSHA to mandate combustible dust safety through the use of NFPA codes, and companies are urged to proactively follow these guidelines when setting up a good housekeeping program.
The NFPA standards that the OSHA Hazard Alert refers to being applicable to dust explosion hazards are NFPA 654, 61,484,664 and 655. In brief, the standards call for establishing regular cleaning frequencies to minimize dust accumulation on walls, floors and horizontal surfaces such as equipment ledges, above suspended ceilings and other concealed surfaces. The standards further state that vigorous sweeping or blowing down with steam or compressed air only should take place after the area or equipment has been vacuumed, due to the creation of dust clouds by the other methods.
Standards also call for vacuum cleaners to be specified for use in Class II hazardous locations or be a fixed pipe suction system with a remotely located exhauster and dust collector. When flammable gasses are present, vacuum cleaners need to be listed for Class I and Class II hazardous locations.
NFPA 61 for food and agricultural processing plants has somewhat reduced precautions compared to the previously listed standards. NFPA 484 for combustible metals requires that dust and particles be cleaned with non-conductive scoops or soft, natural brushes or brooms before the dust is vacuumed. In addition, vacuums are suggested to pick up dust that is too small to be picked up with brushes. Blowing combustible metal dust with air compressors is not permitted.
For cleanup of truly explosive materials such as gunpowder, rocket propellant, sodium azide and aluminum powder, which can explode if collected in dry form, a submerged recovery vacuum cleaner is available and designed specifically to pick up explosive powders safely. The explosive or hazardous material is submerged under fluid to render it inert. The unique design includes not only a high liquid level safety shut-off, but also a low liquid safety shutoff to prevent vacuum operation if insufficient liquid is in the drum.
HOUSEKEEPING FOR FINE POWDERS AND CHEMICALS
Industrial vacuum cleaner experts are skilled at designing systems around a company's particular needs. For instance, a custom job shop fabricator faced potential flammability issues because they couldn't adequately sweep the fine powder coating residue from the floor, lights, booth walls and components of their facility. Shop-type vacuums they had been using posed a static electric shock to the workers and productivity suffered. Not only did they have to vacuum, but they also had to clean by hand using wet rags to prepare booths for the next powder-coating job.
To eliminate any shock, fire or explosion hazard associated with electric or engine driven units, the fabricator installed a Venturi compressed air-powered vacuum with antisparking vacuum inlets and grounding lugs; static conductivity from end to end, including a static conductive hose with internal ground wire; and grounded end cuffs, which prevent static build up.
To further reduce sparking danger, static-conductive filters rated 99.9 percent efficient at one micron were used, which virtually eliminated any fine particle discharge from the vacuum's exhaust back into the work area. This helped to create healthful, productive breathing conditions in the workplace.
Furthermore, a unique pulse jet filter cleaning system on all the company's air vacs not only increased color changes in the powder coating industry but also ensured high vacuum efficiency while virtually eliminating clogged or “blinded” filters. By simply pushing a button on the air vac, the operator can backwash the filter with compressed air instead of taking the vacuum apart to clean the filter by hand.
For many manufacturers and processors, industrial vacuum cleaners now are being completely integrated into production and process systems, and are quickly becoming a key component of critical strategic issues that range from productivity to environmental safety and worker health.
Regardless of the political aspects of any combustible dust legislation, companies need to be proactive in implementing standard housekeeping practices. Since 2006, there have been nearly 100 reported dust fires and explosions, and no company executive wants to be responsible for allowing the makeup of a catastrophic explosion.
Lisa Zocco is a technical writer based in Long Beach, Calif., specializing in industrial manufacturing and B-to-B industries. To learn more about industrial vacuum cleaning systems for production lines and other dust-intensive areas, visit http://www.vac-u-max.com.