Safety is a clear -- if broad -- priority spanning all industrial sectors. It encompasses plant, machine, and worker safety; ergonomics; environmental standards; and security. Companies continue to strive to eliminate downtime -- in some sectors, an hour lost is a day's production lost. Yet companies often design safety problems into their operations.
"One of the most frequent mistakes system designers make is thinking only of the production process and ignoring the fact that the system will be safeguarded later to prevent injury before it is put into productive use," comments Steve Freedman, safety controls manager at SICK Inc. "The result is that operators often find the safeguards inhibit their ability to perform their jobs efficiently, resulting in reduced productivity. Many operators therefore unwisely bypass the safeguards in order to keep a sustained production pace or troubleshoot equipment." Such design flaws have become "one of the most frequent causes of machine related accidents in automated production today," Freedman believes.
Designing a safeguarding system "first requires a clear understanding of the hazards that exist in the system," continues Freedman, plus a thorough knowledge of appropriate technologies. For example, Presence Sensing Device Initiation (PSDI) simultaneously safeguards personnel and starts the machine cycle, which has "significantly improved productivity for many companies while reducing the ergonomic repetitive stress of a separate cycle-start button," Freedman notes. Another must: "Properly interfacing safeguards with the machine control and/or e-stop circuitry." Off-the-shelf technology is available to meet that need. "Prepackaged safety relays (DIN Rail mountable pre-wired circuits) are a readily available way to reduce safety circuit design time and wiring errors," observes Freedman, along with safe PLCs and bus networks. (For more, click here.)
Industry has turned to several innovative technologies to enhance safety, including Intelligent Assist Devices (IADs). "The need for IADs results from the need to reduce injuries, [and] improve productivity and quality, combined with the fact that today's 50-year-old material handling technology can provide no further improvements," according to Cobotics CEO and president Paul Decker.
Ergonomic Factors
"The annual cost of overexertion and repetitive trauma injuries to the world's major manufacturing industries exceeds $32 billion, and there has been no material reduction in injury rates for the past three years," states Decker. General Motors, Ford, and other companies "have gone so far as drafting an ANSI safety standard that prescribes how IADs can be implemented in their factories, thereby eliminating what would have been a significant barrier to widespread adoption of IADs," he adds. (For more, click here.)
"Preventing ergonomic injury without the benefit of accepted personal protective equipment product guidelines" tops the list, according to Chase Ergonomics Inc president Gary Shumate. "The word 'ergonomic' has become a buzzword, and is slapped on products ranging from software to ceiling fans. Personal Protective Equipment (PPE) may be labeled ergonomic, but it's all just so much chatter unless there is independent, reliable confirmation of the claim." He warns that the "incidence of ergonomic injuries in the U.S. borders on epidemic."
Common repetitive stress disorders are well publicized, while other problems have just begun to gain attention in the U.S. workplace. Shumate notes that "thousands of cases of vibration-induced HAVS (Hand-Arm Vibration Syndrome) have been diagnosed, but due to the wide variety of symptoms and a lack of awareness of the syndrome, and perhaps because of lack of media attention, undoubtedly thousands of cases go unreported and untreated." And musculoskeletal disorders (MSDs), which affect soft tissue, "can be difficult to diagnose and equally difficult, if not impossible, to remedy," he adds.
In the absence of an OSHA ergonomic rule, U.S. industry looks to international standards for guidance on Personal Protective Equipment (PPE). "General categories which fall under the ergonomic PPE umbrella, and which were discussed during the OSHA hearings, are cold weather gloves, palm and knee pads, back supports and anti-vibration or vibration-reducing gloves," continues Shumate. ANSI confirmed the ISO standard for vibration-reducing gloves in April 2002 (ANSI S3.40-2002: ISO 10819:1996). "Asking a factory representative or distributor sales associate whether his or her AV gloves have passed the ISO (and now ANSI) standard for effective vibration reduction is a good way to verify anti-vibration claims," Shumate suggests. "Ask to see the test results." (For more, click here.)
Southworth Products Corp president Brian McNamara points to the recent trend "toward incorporating multiple functions into a single machine." For example, "machines that were once fed by forklifts (container tilters, pallet levelers, and work positioners) now feed themselves." That means operators "don't have to wait for the forklift driver to deliver or remove the next batch of parts. Productivity improves and the risk of accident or injury is reduced," according to McNamara. (For more, click here.)
Ed Brown, president of Topper Industrial, notes: "Work that is poorly designed can gradually lead to injuries that are just as debilitating as trauma. Accidents can be avoided. But the slow effects of strain on the arms, back, and legs creeps up on workers and eventually affects the ability to carry out the requirements of an assembly job." Brown implicates forklifts as a leading cause of accidents. "This vehicle is the factory workhorse for moving parts and products throughout a facility. But the combination of a rapidly moving 5 ton forklift and people on the factory floor presents a high level of hazard." Topper is working with automakers to develop the Ergo-Cart line of container carts, built with wheels and casters "so workers can push the load into the desired position with minimal effort," Brown tells IEN. Heavy-duty frames can handle loads "to 3,000 lb and beyond [with] tilt mechanisms for easy access." (For more, click here.)
Explosions in hazardous locations pose a major safety risk as well. "These locations are classified by the amount, type, and frequency of the presence of hazardous gases," explains Wieland Electric Inc product manager Marc Immordino. "Certain protected electrical devices can protect the area and workers from the dangerous combination of electrical sparking and flammable gases." The company also "realized that its NEMA and IP rated devices were sealed properly in order to be approved for hazardous locations use," Immordino notes. "For instance, fully enclosed DIN rail mountable relays are able to be used in standard enclosures within Class I, Zone 2 locations. The idea is to eliminate the possibility for arcing or sparking where flammable gases may be present." (For more, click here.)
Security Concerns
According to Bernie Cowens, vp of security services at Rainbow eSecurity, the "primary security concerns facing manufacturers are hackers from inside and outside the company, both in the physical world as well as the information world." Now authentication technology not only "identifies and allows people into buildings, but allows users to access the network and data. Today's authentication tokens, like the Rainbow iKey, provide granular access control to secure the network and applications, and secure data transactions," he adds. "Constant authentication is one sure-fire way for companies to make sure that the people who are accessing the company's data, networks, and possibly secrets, are really who they say they are."
Increased worker mobility requires enhanced Web security. And manufacturers now deploy "appliances that secure access to these Web-enabled applications, optimizing the online server performance in the process," Cowens continues. Additionally, "wireless devices should have encryption applications installed that encrypt the data stored on the device." Wireless LANs use wired equivalency protocol (WEP) to secure PDA links. WEP can slow the PDA connection to "where it's practically unbearable," while PDAs with 200 MH processors "really don't have the horsepower to do the encryption to make the link secure," says Cowens. "Usually, users end up turning the WEP off and losing all security across that wireless link." (For more, click here.)
Property theft losses exceed $8.1 billion annually, according to the FBI's 2000 Uniform Crime Report, accounting for about 2% of the total value of construction and industrial facilities and job sites. Products such as Ingersoll-Rand Co's Kryptonite Flex Security line of anchors, chains, cables, and padlocks are designed to prevent crimes of opportunity, and reduce unauthorized use of tools and equipment by trespassers. Kryptonite combines alloys of triple-heated boron, manganese, Kryptonium, and molybdenum in security devices for high-risk locations. (For more, click here.)
Training is crucial. Symtron Systems Inc uses full-fledged simulation as a key part of its curriculum. "The system's simulated smoke is nontoxic and water run-off from the trainer can safely be discharged into conventional drainage systems," notes Symtron marketing manager Louis Orotelli. "Scenarios can be configured to represent class A, B, and C fires -- Instructors can manually control the lesson or allow the system to automatically detect the proper application of extinguishing agent. If insufficient agent is applied, the fire will surprise the trainee by rekindling." (For more, click here.)
Impact of Technology
Looking at light curtains, mats, interlocks, and relays, Tom Knauer, vp of marketing at STI, believes that "safety networks and buses will emerge, similar to the DeviceNet/Asibus/Profibus systems in use in industrial automation today." (Pictured, STI's MCJ4700 light curtain.) Knauer also sees broader applications for laser scanning devices, the spread of safety vision systems, and "more sophisticated device diagnostics." He does not view the Web as an important factor "in terms of safety networking," but the Internet will play a role in "providing documentation, training, and support." (For more, click here.)
Omron safety product marketing manager Reno Suffi says bus technology already is migrating to the safety sector. "Applied redundant bus and the ability to perform self-monitoring functions can make a safety bus system perform with the equivalent level of reliability as a traditional hardwired safety system," comments Suffi.
"It is likely that more and more electrical interconnect devices will be designed and approved for hazardous locations," Immordino predicts. "The safety factor increases exponentially when individually approved devices are used. This is because the large and expensive intrinsically safe enclosures are often not maintained properly."
At some point wireless technology will play a role in safety. Knauer comments: "In machine safeguarding, not in the near future -- except for non-safety data gathering purposes. Eventually, yes -- once reliable wireless networks are developed that can meet the safety standards and requirements."
Cost-effective safety is essential, Immordino emphasizes. "Control engineers need a quick, reliable and safe way of ensuring the connectivity and control operations of a hazardous location. Utilizing individually approved devices is all of these things. Class I, Zone 1/Zone 2 approved interconnect devices, such as rectangular, modular connector systems, relays, and terminal blocks are rapidly becoming the choice for retrofits." Immordino urges companies "to install hazardous locations-approved devices before they are needed," in light of the rapid changes in Zone classifications in recent years.
"The most flexible machine in the factory is the human being," asserts McNamara. The key to optimizing human flexibility and machine efficiency is ergonomics. "For this reason, it has become important for manufacturers to provide machine operators with ergonomic lifting, leveling, and positioning equipment that will help them keep up with faster production machines and to do it consistently for a full shift without fatigue," McNamara tells IEN.
As for integrating safety and security, Knauer contends the two do not necessarily connect. "Though there may be technologies that are common, safety and security have very different market drivers and the applications do not really overlap," he notes. "Perhaps safety interlock switches have security applications, but the primary use is, and will remain, to protect machine operators."
