Of all the continuous-improvement efforts manufacturers can undertake, none is more vital than plant safety. Steady state is not an option when it comes to safeguarding an organization’s human assets.
Machine guards, light curtains, protective clothing and slip-resistant surfaces long have been mainstays in the safety toolbox. More recently, companies have focused on training programs that elevate behavior modification to a religion. But environmental hazards and human nature are powerful forces that are difficult to control. Perhaps the best approach blends human and technical elements, making sure people understand the hazards that exist and equipping them with the right tools to safeguard their well-being.
Process industries such as food can be particularly challenging because of the contained areas, ignitable materials and potential electrical hazards, cautions Mary Capelli-Schellpfeffer, a specialist in occupational medicine with a focus on arc flashes and other electrical dangers (see related story on page 54). February’s explosion at Imperial Sugar’s Savannah, GA refinery was a grim reminder of combustion dangers: At least six workers died, and 35 were treated at burn centers. One quarter of the combustible dust explosions since 1980 occurred at food plants, the US Chemical Safety Board found.
Zero-tolerance for injuries may be as unachievable as zero-tolerance for E. coli in ground beef, but many organizations are striving for it. The effort is aided by new disciplines such as cognitive engineering, designing systems to account for the way people assimilate information and apply it in their environment. But the work environment is constantly changing. Deployment of robotics changes the way people interact with machines, for example, and unseen particles in the air can sicken workers unexpectedly. How injuries are codified can obscure the underlying cause: A worker shocked by electricity might plummet to his death from a scaffold, and the incident would be lumped with slips and falls.
Triennial revisions to the National Electrical Code and electrical standards, as set by the National Fire Protection Association (NFPA), are being introduced this year. Capelli-Schellpfeffer advises manufacturers to seize the opportunity to reevaluate overall safety, rather than leaving it solely to the staff electrical engineer. “Integrate the new insights into the broader understanding of how the plant’s processes are secured,” says the principal of CapSchell Inc., Chicago. “Process engineers, facilities managers and others need to be involved in a reassessment of how systems work together and where previously underappreciated hazards lie.”
A seemingly modest change this year could have major implications for machine safety. NFPA 79 specifies that “final removal of power to the machine actuators shall be ensured and shall be by means of electromechanical components” in the event of emergency stops for machine jams and other exceptions to lock out/tag out procedures. NFPA is introducing an exception, permitting “drives or solid state output devices designed for safety-related functions” as the final switching element. The change harmonizes US safety standards with those in Europe, where safe-motion controls are common.
It’s not an iPod; it’s a hands-free, eyes-free voice-based picking system. Productivity improvements yield hard-dollar savings over handheld scanners and other communications media, but voice systems also produce a safer work environment at Dunkin’ Donuts Mid-Atlantic Distribution Center. Source: Voxware Inc.
Safe robot motion
Defeating e-stops and light curtains to make minor machine adjustments is almost a challenge to the ingenuity of an operator, proponents of the new exception argue. Whether motivated to achieve higher productivity or to simplify their own routines, people find ways to defeat safety systems. A study by a German worker’s compensation consortium found that safeguarding equipment on 37% of machines evaluated was temporarily or permanently disabled. Instead of trying to overcome human nature, safe-motion controls and drives integrate motion control and safety control, and allow the operator to do his job without hindrance, removing the motivation to tamper with safety guards.A risk assessment of a machine is required before safe-motion and standstill controls can be used, and a safe maximum speed during any procedure must be established. “If there is a failure, it’s in such a way that it is in a safe state,” says Kelly Schachenman, manager of safety-systems marketing at Rockwell Automation in Mayfield Heights, OH. US machine makers serving the international market are under pressure to incorporate risk-based controls in their designs, and automotive manufacturers see tremendous productivity gains with this approach, particularly in robotic systems where workers must enter the work envelope while the machine is powered. As a result, Rockwell is beefing up its control-reliable safety systems.
“Machine operators will ignore or override safety rules to do what needs to be done,” Schachenman points out. “By controlling speed and inertia force, you enable collaboration between the operator and the equipment in a way that is less likely to result in injury.”
In an analysis of safe-motion technology, Sal Spada of ARC Advisory Group wrote, “The European market has effectively demonstrated that machine utilization does not have to be traded off for increased operator safety.” He cited Swedish and Japanese studies of robotic accidents that concluded most accidents occur during programming, setup, changeover and basic maintenance, when perimeter guards must be disabled to allow someone inside the work envelope while the machine is operational.
The Dedham, MA-based analyst tabbed Bosch Rexroth Corp. as the leader in safe-motion technology. Safe-motion programming first surfaced in the firm’s drives in the late 1990s. Most of the drives it now sells have integrated motion and safety control.
Safety PLCs are best suited for large, complex machines, says Rami Al-Ashqar, product manager-electronic drives & controls at Hoffman Estates, IL-based Rexroth. For packaging machines and other high-speed equipment, “safety on the drive makes the most sense,” he says. “A couple of hundred milliseconds can mean the difference for a finger.”
Fingers will have to fend for themselves for the time being. Despite the technology’s acceptance elsewhere, US professional organizations still are vetting safe-motion. “If Underwriters Laboratory said this is okay, there wouldn’t be a debate about it,” Al-Ashqar notes. But UL approval is probably a year away, leaving task-oriented safety on the sidelines.
Low awareness of the change also works against the technology. “We’ll listen and take information, but none of us is going to put ourselves in a position of using new technology until OSHA says the NFPA and IEC standards cover this adequately,” insists Michael Coleman, safety manager at the Springdale, AR plant of Rockline Industries. Coleman also chairs the manufacturing branch of the American Society of Safety Engineers (ASSE), and the NFPA change was news to him.
Specialty clothing and other protection can minimize injuries from arc flashing and other dangers. Source: Oberon Company.
Hands free, eyes free for safety
Worker safety and increased productivity also are the appeal of voice software for order-picking and inventorying of raw materials and finished goods. Productivity gains of 10% over scanner-based picking are typically realized with voice systems, according to Scott Yetter, president of Lawrenceville, NJ-based Voxware Inc., “and users generally cut their error rate in half.” Reductions in worker injuries may be considered “soft savings,” but the dollar amounts can be significant, he adds.Handheld scanners and on-board video monitors boosted distribution efficiency, and now leading soft-drink bottlers and other food companies are graduating to voice systems to deliver instructions. One of the early adopters was Dunkin’ Donuts Mid-Atlantic Distribution Center (MADC), a cooperative owned by 7,000 restaurant franchisees in eight states. Since system installation in 2004, payments for worker’s compensation claims are down 71%, reports Warren Engaard, director of operations. The DC also has seen a reduction in its Mod Rate, the insurance industry measure of a company’s work-safety competence. That has meant lower insurance premiums.
By replacing clipboards with a voice system, MADC freed workers’ eyes and hands, a safety and efficiency benefit that would not have been realized with scanners. The change also eliminated a chronic danger with lift-truck operators. “They kept hitting a sheetrock wall,” Engaard ruefully notes. “One guy ran his forklift right into the ladies’ bathroom on the other side of the wall.”
MADC deployed 93 voice units in its Burlington, NJ facility. Eight full-time order checkers were made redundant by a system that consistently delivers 99.8% accuracy rates. Their annual pay alone exceeded system cost. The new DC also was designed to isolate lift-truck traffic from workers with electric pallet jacks.
“We went from being a company having a difficult time getting insurance to one that now gets back [premium] rebates,” says Engaard. “Everybody wants to put safety first, and now we have a building design and voice system that help us do it.”
Voxware uses a TTS engine that emulates the speech patterns of each worker using it. An individual repeats 250 phrases that are phonetically translated by the system. Whether the worker has a Southern drawl or speaks fluent Brooklynese, the system emulates his enunciation when delivering instructions. As many as 28 languages can be programmed into the system, Yetter says.
Drives that feature both motion and safety controls are incorporated into SIG’s ABF 610 filling system, allowing operators to safely clear bottle jams without cutting power to the machine. Bosch Rexroth supplies the drives. Source: Bosch Rexroth Corp.
Air supply
How an organization responds to a health and safety issue is at least as important as preventive steps on the front end. By that measure, the cooperative investigation by public health officials and pork processors in Austin, MN is a textbook example of a proactive response. Company nurses at Quality Pork Processors Inc. (QPP) alerted health authorities last year when they noticed a pattern of neurological illnesses in employees who worked in close proximity to a table where pig brains were extracted (see related story on page 52).As the Austin situation illustrates, dangers to human health in a manufacturing environment arise in unexpected ways. While a definitive conclusion regarding the cause has not been reached, circumstantial evidence is growing that inhalation of small particles of brain tissue triggers an auto-immune response in some people. Since a suspected process was suspended, only one additional patient has been identified. According to Dr. Michael Osterholm, an expert in infectious disease epidemiology, the latest case is consistent with other illnesses in that none of the affected workers were more than 15 feet away from a point where brain tissue could become airborne.
Several months passed before healthcare professionals recognized a link between sick workers and where they worked in QPP’s plant. When the Minnesota state epidemiologist raised the possibility of a link between a brain-removal process and the illnesses, Owner Kelly Wadding immediately suspended the process. Goggles and face shields were added to workers’ protective gear. “There’s no bad guy here,” says Wadding. “I don’t think anyone could have foreseen this.”
“Kelly Wadding’s done a very good job on safety,” adds Richard Morgan, president of Local 9 of the United Food and Commercial Workers Union.
Contrast the QPP case with the response to worker illnesses associated with inhaling diacetyl vapors. The chemical lends a buttery flavor to snack foods, but as early as the mid-1990s, it was suspected of causing bronchiolitis obliterans in exposed workers. In 2001, the National Institute for Occupational Safety and Health issued a bulletin linking the lung disease to the chemical, and in 2003, the agency urged manufacturers to make ventilation changes and provide respirators to at-risk workers. Respiratory problems for mixing-room workers in microwave-popcorn processing became so prevalent that bronchiolitis obliterans came to be known as “popcorn workers disease.” Six deaths and multi-million dollar lawsuits have resulted, but not until doctors linked consumer exposure to diacetyl in microwave popcorn did manufacturers switch to other ingredients. Within four months, retail shelves featured microwave popcorn with “no added diacetyl” boasts on the cartons.
Food safety is about more than future sales. Similarly, plant safety is about more than reducing insurance costs and injury claims, though a compelling economic case can be made: ASSE estimates occupational injuries cost businesses $171 billion a year. Workplace safety programs can reduce those costs 20-40%, ASSE estimates, not including the cost of absenteeism and product defects. After all, if the well-being of the people who make the product isn’t a high priority, what message is the company conveying regarding the well-being of the people who consume the product?
For more information:
Sal Spada, ARC Advisory Group, 781-471-1000
Rami Al-Ashqar, Bosch Rexroth Corp., 847-645-3746, rami.al-ashqar@ boschrexroth-us.com
Mary Capelli-Schellpfeffer, CapSchell Inc., 773-960-5802
Kelly Schachenman, Rockwell Automation, 440-646-3511,klschachenman@ra.rockwell.com
Joseph Weigel, Square D Co., 615-844-8656
Scott J. Yetter, Voxware Inc., 609-541-4100
Air quality and the safety equation
With the early-February identification of a 13th worker suffering from a neurological disorder at the Quality Pork Processors plant in Austin, MN, public health officials solidified their theory that atomized brain tissue from slaughtered hogs is the root cause.The 13th diagnosis involved a Hormel Foods employee who worked in a rendering room below the area where the previously diagnosed employees worked. “The heads come down to rendering with a lot of energy, causing splattering of some brain matter,” explains Michael Osterholm, the director of the Center for Infectious Disease Research and Policy in Minneapolis. Dr. Osterholm is serving as a consultant to Hormel in the investigation.
Epidemiologists suspect an auto-immune system reaction was triggered after the workers inhaled or otherwise absorbed particles of harvested brain tissue. Tingling and numbness in limbs, fatigue and difficulty walking are among the symptoms. Nine of the affected workers have returned to work, and “the ones we’ve been able to identify and treat right away are doing quite well,” according to QPP Owner Kelly Wadding.
QPP was one of three US slaughterhouses that used pressurized air to harvest pig brains for human consumption. Compressed air enters the skull through a needle inserted at the base of the medulla oblongata. The pressure turns brain mass into a slurry, which comes out the same opening. QPP had used the technique since 1997. The first worker illness was diagnosed in December 2006. Wadding ordered a halt to the practice in November 2007.
The same technique was used at Indiana Packers Corp, Delphi, IN, a joint venture of Mitsubishi Corp. and Itoham Corp. At least two IPC workers have exhibited neurological symptoms similar to those at QPP. A Hormel Foods plant in Fremont, NE also used high-pressure extraction, but no worker illnesses have been identified there.
Arc-flash hazards and the maintenance onus
Revisions to National Fire Protection Association (NFPA) standards for electrical safety in the workplace put new teeth into electrical maintenance routines, and industrial firms are scrambling to comply.Given the piecemeal additions and changes that occur in most plants, “detailed” and “electrical diagrams” are not words often used consecutively. NFPA 70B requires such analysis, “but nobody does maintenance around that standard,” bemoans Joseph Weigel, product manager at Nashville, TN-based Square D Services Marketing. That is changing, however, because practices recommended in NFPA 70B are now incorporated into NFPA 70E, as safety experts strive to curtail the potential for arc-flash explosions.
Five to 10 injuries due to arc-flash explosions result in injuries and lost work time each day in the US, estimates CapSchell Inc., and many more unreported and near-miss incidents happen. “The cost of litigation in each event typically is between $8 million-$10 million,” Weigel says, and one advantage of an audit to ensure 70E compliance is to reduce that exposure. At least as important is the message proper electrical maintenance sends to workers about the company’s interest in maintaining a safe work environment, he adds.
Electrical audits determine the condition of over-current protective devices and generate one-line diagrams and other documentation to help minimize the likelihood of arc flash. But performing those audits will take time, Weigel cautions: An estimated 8 million US industrial facilities are affected, and “less than 3% of facilities have completed the arc-flash analysis,” he says. “It’s going to be years before all the engineering studies can be done.”
