Stop pickin' up bad vibrations

PRACTICAL WELDING TODAY® MAY/JUNE 2006

May 9, 2006

By:

Hand-arm Vibration Syndrome (HAVS), vibration white-finger, and carpal tunnel syndrome are all side effects of vibration overexposure, which can occur through using grinders often. Find out how to prevent these effects and reduce your overexposure to vibrations from using grinders and other power tools.

For years vibration overexposure has shortened many careers, causing irreversible damage to workers' nerves, muscles, bones, joints, and blood flow. By understanding the risks associated with overexposure to vibration, you can take safety measures that will prolong your career and result in less fatigue on the job.

Harmful Effects of Vibration Overexposure

Hand-arm vibration syndrome (HAVS) is a chronic disorder that has plagued the welding and fabrication industry for decades. By ignoring its symptoms, you may end up with a painful and eventually debilitating condition.

HAVS may result from regular occupational overexposure to all types of power tools, including vibrating pneumatic, electric, hydraulic, and gasoline-powered hand tools (such as grinders, jackhammers, chipping hammers, hammers, power drills, and concrete breakers).

This disorder is fairly common not only among metal workers and fabricators, but also electricians, builders, plumbers, and carpenters. The effects of vibration exposure can vary in terms of severity and the length of time it takes for symptoms to appear. Factors such as the type of tool, weight, operating speed, tool ergonomics, user body characteristics, environmental conditions, and the use of vibration-dampening accessories affect the overall severity.

Initial symptoms include a tingling or numbing sensation in the fingers and hands. Symptoms can develop anytime from a few months to several years, depending on the many factors involved. As this exposure continues, especially in cold conditions, the pain begins to intensify. If untreated, these symptoms can lead to vascular and sensorineural damage, which can progress to vibration white finger and carpal tunnel syndrome.

Vibration white fingeris a condition of the fingers, hands, and arms that starts with a tingling sensation in the fingers with numbness. Fingers become white and swollen when cold and red and painful when warmed up again. It results from a lack of blood flow, which can lead to nerve, muscle, bone, and joint damage. The lack of blood to the fingers can lead to a loss of the sense of touch or use of the hands. In severe cases, it can turn to gangrene, which leads to irreversible damage and eventually amputation. Another debilitating side effect of overexposure is carpal tunnel syndrome. This occurs when too much pressure is placed on a nerve in the wrist. The symptoms include aching and numbness or tingling in the thumb, some of the fingers, and sometimes part of the hand.

Tips and Tools: Reducing Overexposure

Government and private health and safety groups, industry, and tool manufacturers have conducted research to understand better the long-term effects of vibration exposure, but currently no official standards or guidelines are in place. However, manufacturers and suppliers have designed products intended to help prevent and control the vibration exposure that can result in HAVS.

For example, some large- and small-angle grinders incorporate vibration-dampening technology. This can include a vibration-dampening side-assist handle. Some large-angle grinders have similar vibration-dampening technology built into the body near the rear handles. These types of advancements are designed to help reduce overexposure and add comfort (see Figure 1).

Figure 1
The grinder on the left does not incorporate vibration-dampening technology.
The grinder on the right has a vibration-dampening side-assist handle.
This type of technology is geared toward reducing HAVS discomfort and injuries

Safety gear, such as vibration-dampening gloves, also can offer added comfort and help alleviate symptoms. Contractors, safety groups, and some manufacturers have developed training programs and published suggested guidelines for vibration limits and safe usage times to help reduce some of the harmful side effects of vibration overexposure.

Because a grinder is a commonly used tool—and one of the tools closely associated with HAVS—you should keep several guidelines in mind during operation. The following tips can help reduce the risk of HAVS and other vibration-related disorders:

  • Look for a grinder with vibration-dampening technology, such as side-assist handles or built-in reduction rings. New technology is introduced continually to address vibration reduction, so be sure to investigate the latest developments.

  • Try different grinders. See how the handles feel to your grip and how the tool balances when you use it. Select a model that has a low vibration level and a valid test record.

  • Take frequent breaks, and alternate between stressful and less stressful tasks and grip positions.

  • Use a comfortable grip when working with the tool. Allow your fingers to fit on the tool's entire handle. Don't use tools with handles that will dig into your hands: A soft grip on handles reduces stress. As the saying goes, let the tool do the work.

  • Use heavily padded antivibration gloves to help absorb and dissipate some of the vibration. These gloves should be available in the gear and apparel sections at your local distributor. Remember to keep gloved hands away from the spinning disks.

  • Limit high-vibration work in cool environments, and direct exhaust away from hands. Cold aggravates and intensifies the effects of HAVS, as it further slows and reduces blood flow to the hands. Be especially careful to take extra breaks and precautions in colder weather.

  • Maintain your equipment on a regular basis. Clean all components and replace worn parts. A regular maintenance program keeps your grinder in top shape, providing you with consistent results.

  • Find the right balance between power and weight. The lightest tool doesn't always mean that the job can be done more quickly.

  • Talk to your employer and co-workers about the risks associated with HAVS and how you can prevent potential injury.

Stay Healthy by Doing Your Part

No one has determined a specific quantitative exposure limit that will eliminate the risk of developing HAVS in all end users exposed to hand-transmitted vibration from vibrating tools. Stay alert on the job, and understand that most symptoms don't appear in the early stages. No single factor prevents HAVS or a vibration-related disorder, so you need to be aware of the potential risk and take multiple precautions throughout your career.

Even though you're logging long hours on the job, you need to maintain your focus on your long-term health. The threat of HAVS is real, but you can reduce the risks, whether you're using a tool associated with HAVS at work or off the job. Staying educated and raising your health and safety awareness are the keys to a long and productive career.

Welders reflect on vibration-dampering equipment use
By Stephanie Vaughan, Associate Editor

       Bob Rehl and John Ayers may have two different weld preparation needs, but they share the same feeling: vibration-dampening technology makes a difference.
       Both welders have been using grinders with antivibration technology and said that they won't go back to any other type of grinder.
       Rehl has been using Bosch grinders with vibration-dampening grips for about four months, but he started using them somewhat by accident.
     Rehl owns Rehl Welding, Zanesville, Ohio, but currently is fabricating 72-foot beams in Louisiana, helping rebuild the levee systems destroyed by Hurricane Katrina last year. From his years being a welder, he knows all about the vibration sensation he gets when he's grinding—and after he's completed the job.
       "With some [grinders], your hands are still vibrating after you're done working," he said.
     When he got down to Louisiana, he decided to try a vibration-dampening grinder.
       "We noticed the difference after we started using them. We caught onto them by accident, but were very pleased with them," he said. He explained that the beams he's fabricating have to be 100 percent visually and 10 percent ultrasonically tested, so to pass these inspections, a lot of grinding is necessary. Grinding is especially important where tack welds are concerned, which sometimes can be more difficult to grind than others.
       "Sometimes the tackers just aren't the greatest in the world, and they'll make a great big tack, and you pick up a lot of vibration when you go to grind it because they'll grind and skip. When it went to do that [with the vibration-dampening grinders], you didn't feel the vibration in your hands," he said.
     Comfort in tight areas has been a bonus with the vibration-dampening grinders.
       "When you're inside the web on a beam, you don't have a lot of room to work around," he said. "I won't buy another [grinder] without one [antivibration grip] on it."
       Ayers decided to try vibration-dampening grinders after getting frustrated with how often he had to replace the grinders he was using.
     The foreman of Fabricated Products of Tampa, Ayers fabricates railings with five co-workers, all of whom use small-angle grinders daily.
       "Sometimes you're grinding for two hours," he said, noting that the vibration often was evident after his grinding work was complete.
     In Ayers' case, price wasn't an issue. He said the grinders he bought were priced competitively with the ones he had been using, and he found that in addition to reducing vibration, the grinders also last longer than the ones he'd been using.
       "They are a lot smoother, and you're not hanging onto something that's vibrating you and making your arms numb," he said. "It makes a big difference in the comfort."

Mitch Burdick is the product manager for grinding and metalworking tools, Bosch Power Tools and Accessories, 1800 W. Central Road, Mount Prospect, IL 60056, 877-267-2499, www.boschtools.com.



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