In nearly all industries, the National Fire Protection Association (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.” Despite NFPA and OSHA recommendations, many companies 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. 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.
In an effort to bring 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 and lists different types of materials that can generate combustible dust,” according to Foulke.
“Industries covered by the NEP include food, coal and metal processing, chemicals, textiles, tire and rubber manufacturing, paper, pharmaceuticals and recycling operations. These industries deal with a range of combustible dusts with differing properties, including metal dusts, coal and carbon dusts, plastic dusts, biosolids, certain textile materials and organic dusts.”
Although using vacuums isn’t new, many companies have tried to use shop vacuums to clean up dust, and have found them inadequate under the rigorous demands in the processing industry. In stark contrast to weak shop vacuums, powerful industrial vacuums can suck up tons of material an hour, but most people don’t associate that type of volume with vacuum cleaners. People have a concept of what they have at home and often need education.
To prevent dust explosions, VAC-U-MAX founder Frank Pendleton developed the first air-operated industrial vacuum. Firsthand experience taught him the hazard had to be safely and efficiently removed, and he knew the dust surrounding 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 startup, Pendleton began engineering a solution. In 1954, he introduced the first air-operated vacuum cleaner, which was three times as strong as its electrical counterpart and posed no sparking hazard.
Since then, VAC-U-MAX has been a pioneer in solving vacuum-related challenges in a range of industrial settings—from powder coating and metalworking to chemical and pharmaceutical.
Although there has been many technological advances over the last 50 years to prevent dust explosions, good “housekeeping is vital because without the accumulation of combustible dust, catastrophic secondary explosions will not occur,” says Foulke.
Of the 17 existing standards actively targeted by OSHA, housekeeping dominates. However, even with OSHA’s increased enforcement, NFPA standards and the CSB’s push for tougher adherence, CSB Chairman and CEO John Bresland reported at the Senate hearing that “in the two years since the CSB compiled the data for the combustible dust study, media reports indicated the occurrence of approximately 82 additional dust fires and explosions.” He added, “CSB estimates that a percentage of those explosions could have been prevented if there were standard housekeeping practices in place.”
After the Imperial Sugar refinery exploded due to a 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 and states, “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 damages, have been caused by secondary explosions.”
After Imperial Sugar’s Port Wentworth sugar refinery exploded, the company willfully refused to remedy similar conditions at its 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 standards, a lack of understanding of housekeeping standards and misconception of the relatively low cost of vacuum systems prevail. 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 selection of an industrial vacuum-cleaning system is based primarily on application. In some cases, small air- and electric-powered drum units suffice, while others require large central electric- and diesel-powered units for multiple users and filtration systems capable of capturing particles that are invisible to the naked eye. Similarly, some applications require sophisticated custom vacuum cleaner installations. For others, compact off-the-shelf systems are adequate.
Frequently, industrial vacuum-cleaning system users assume they need a one-of-a-kind solution when their application actually calls for a pre-engineered product. In other words, most applications require standard equipment that offer options to best fit an application.
Because proponents of H.R 5522 are urging the Senate to ensure OSHA mandates combustible dust safety through the use of NFPA codes, it is suggested that companies 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. Except for NFPA 61 and 664, which deal with combustible metals and food/agriculture products respectively, the fugitive dust control standards are generally the same for manufacturing, processing and handling of combustible particulate solids.
In brief, the housekeeping standards call for establishing regular cleaning frequencies to minimize dust accumulation on walls, floors and horizontal surfaces. The standards further state that vigorous sweeping or blowing down with steam or compressed air should only take place after the area has been vacuumed due to the creation of dust clouds by these 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 gases are present, vacuum cleaners need to be listed for Class I and II hazardous locations.
NFPA 61 for food-processing plants has somewhat reduced precautions than the previously listed standards, and 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 isn’t permitted.
For cleanup of truly explosive materials, a submerged recovery vacuum cleaner is available. It’s designed to pick up these powders safely; the explosive or hazardous material is submerged under fluid to render it inert. This unique design includes not only a high liquid level safety shutoff, but also a low liquid safety shutoff to prevent vacuum operation if insufficient liquid is in the drum.
Housekeeping For Fine Powders & Chemicals
Industrial vacuum cleaner experts are skilled at designing systems around a company’s particular needs. For instance, when a custom job shop fabricator faced potential flammability issues because it couldn’t adequately sweep a fine powder-coating residue, and the shop vacuums it had been using posed a static electric shock to workers, productivity suffered. Not only did the fabricator have to vacuum, but it also had to clean by hand, using wet rags to prepare booths for the next powder-coating job.
The fabricator sought out VAC-U-MAX, which offers the industry’s only written static control guarantee. To eliminate any shock, fire or explosion hazard associated with electric- or engine-driven units, a Venturi compressed air-powered vacuum was installed with anti-sparking vacuum inlets and grounding lugs, and static conductivity from end to end to prevent static buildup. 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 also helps create healthful breathing conditions in the workplace.
Industrial vacuum cleaners are now being integrated into 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 this bill, companies need to be proactive in implementing standard housekeeping practices. Since 2006, there have been 82 dust fires and explosions—nearly one a week—and nobody wants to be responsible for allowing the makeup of a catastrophic explosion.