Ergonomics 101

By Jeff Griffin | Jul 15, 2006
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It is easy to take the safety features of today’s hand tools for granted. Tools have come a long way from 40 or 50 years ago. For example, one major supplier of a lightweight reciprocating saw positioned the power switch where it was impossible to turn off or on with the hand holding the tool—-either turn it on and reposition the hand with the blade in motion, or use the other hand.

Turning the tool off quickly in an emergency was impossible—it ran until the hand was repositioned to move the switch to “off,” or the other hand could reach the switch. The power cord was connected to the tool in a place where the cord could easily touch the fast-moving blade.

Remember the set of pliers that, for some unknown reason, had a ridge on its metal handles that pressed uncomfortably into the hand when pressure was applied?

These days, weight and balance of power and manually operated hand tools make them safer and easier to use. Guards and shields of power cutting tools reduce the risk of injury from broken blades, bits or objects thrown by the force of the tool.

Power tools offer the most potential for serious injury, but manual tools—especially when incorrectly or inappropriately used—also pose numerous risks. Innovative safety features are showing up on basic hand tools such as Gardner Bender’s wire stripper with built-in circuit alert. It not only strips wire, but also allows the user to make a noncontact test for the presence of voltage.


Today, any discussion on tool safety today likely includes the term “ergonomics.”

Overused and misused, the term is at risk of becoming a meaningless superlative, similar to “all-natural” and “fat-free” in the food industry. Related to hand tools, physical ergonomics focus on the human body’s responses to physical and physiological loads and pressures encountered during the use of tools. And, while ergonomic features are not focused exclusively on safety, many can and do play a critical role in the safe use of tools.

Power tools

“The most recent power tool safety improvements have been in the area of ergonomics or the feel and comfort of a tool in a user’s hands,” said Peter Domeny, Bosch director of product safety. “Soft or contoured grips, lighter weight designs, side-assist handles, cooler running motors, multifinger triggers and more have made tools easier to use while decreasing user fatigue. The less fatigue a user experiences, the better control and attention they can give their work and avoid injury.”

Vibration-reduction technology in rotary and demolition hammers and reciprocating saws helps reduce cumulative trauma disorders, Domeny said. Internal slip clutches used in combination with side-assist handles can help reduce inertial and stall torque reactions that have been known to break wrists and cause falls off of ladders if a user is not paying attention.

“Grounding and total double insulation of all likely control surfaces reduce the likelihood of electric shock when striking live wires while drilling or cutting into a wall, for example,” Domeny said. “Tools once manufactured with all-metal housings now feature composite housings and rubber gripping areas to not only enhance grip, but also insulate the user against electrocution.”

Roderick Dick, senior product manager, Makita, believes tool buyers expect products from companies with a reputation for delivering quality products to be safe, which allows them to base their purchase decisions on features, brand and availability.

“As hand tools have evolved, they have become not only more productive and easier to use, but also safer,” said Dick. “They use heavy-gauge cable to prevent electrical failures, GFI circuitry for working around water, double-insulated enclosures to provide protection without the need for the ground prong, clutches to protect operators from kickback and the tool from damage, rubber overmold on handles to provide non-slip, secure and comfortable grip, speed controls to tune tool performance to various applications, and waterproof and dust-proof housings to prevent intrusion of foreign substances.”

Hand tools

Jon Howell, Ideal product manager for hand tools, said safety and ergonomics go hand in hand.

“Professional tradesmen,” said Howell, “use their hands all day, every day. Making tools more comfortable and ergonomic not only reduces user fatigue and repetitive stress injuries, but a more ergonomic tool provides more control, making it less likely to slip. Ergonomics brings the use of new materials that make tools more comfortable and durable with handles shaped to fit user’s hands. In addition, features like lanyard looping holes make tools safer when users work on ladders by allowing the tool to be attached to the worker’s wrist [preventing] it from dropping on others working below.”

Ed Liss, Bahco North America marketing manager for distribution, said ergonomic tools are relatively new to the electrical industry.

“Most genuine ergonomic tools feature rounded areas and protective shields that reduce the risk of immediate direct injuries, such as cuts and bruises,” said Liss. “For example, properly designed pliers should have no unnecessary sharp edges, even around the jaws. Ergonomic tools also should minimize the cumulative wear and tear on skin that leads to abrasions, blisters and calluses.

“Screwdrivers that have a hard core should be surrounded with a soft thermoplastic gripping surface to protect skin and preserve the grip. The soft gripping surface improves traction and prevents rubbing. Safe design should also ensure that tools don’t pinch or snag hands between closing parts.

“Ergonomic slip-joint pliers, for example, have handles that remain open even when the jaws are fully shut to keep from pinching palms.”

Liss cautions that any tool can be promoted as ergonomic, but true ergonomic tools undergo a specialized ergonomic design process that takes into consideration cumulative trauma disorders and repetitive strain injuries.

“The design process requires the tool to be thoroughly researched and tested in order to validate the real benefit they provide to the user,” he said. “True ergonomic design results are quantified.”

David Onachilla, senior vice president of marketing at Gardner Bender, said that as the average age of electricians approaches 50, the occurrences of work-related strains and injuries also increases.

“Today, no electrical contracting business can afford to ignore the bottom-line benefits to ensuring its work force is choosing and utilizing the most appropriate hand tools for optimal safety and productivity,” he said.

Hand tools with grips that are easier to hold improve leverage and reduce fatigue. Properly sized handles accommodate pressure points. Neutral-operating position reduces wrist stress. Clear audible and visual indicators eliminate guesswork.

“Multiply these benefits by the number of employees and the electrical contractor’s business will significantly benefit from higher productivity rates and fewer strain and injury complaints,” Onachilla said.

Ed Pulaski, Ripley national sales manager, utility, said he believes buyers recognize the benefits of features designed to make tools safer.

“As a manufacturer,” he said, “we have seen and implemented a number of things to make tools safer. For instance, in stripping tools, we have inserted blades in bushing assemblies that make it less likely that someone will cut themselves while handling a tool. We have spent time developing ergonomic tools that eliminate repetitive motion-type injuries, for instance, a cable stripper that can be used with an electric or battery-operated drill instead of being operated by hand. And, of course, tools are being insulated to protect users from electrical shock.”

Insulated hand tools

Properly insulated hand tools must be used in situations where circuits cannot be shut down, and OSHA requires the use of insulated tools or handling equipment if the tools or handling equipment might make contact with such conductors or parts.

These tools are designed to reduce the chance of injury if the tool should make contact with an energized source.

Insulated hand tools must be clearly marked with the official, international 1,000-volt rating symbol. They also must meet ASTM F1505 standards. To receive the 1,000-volt rating, an insulated tool is tested at 10,000 volts.

“The most important advances in safety are happening in the insulated arena,” said Howell. “Not only are tool design and safety features improving, but even the materials used to create the tools are changing for the better. An excellent example is the Santoprene material we use on our insulated tools.

“Santoprene is resistant to harmful chemicals, oils, hydraulic fluids, etc. Injection-molded Santoprene material makes it possible to have two layers of plastic with different strengths. The underlying yellow layer acts as an at-a-glance safety check—if the orange outer coating reveals any of the inner yellow surface, an electrician will know that the tool needs to be replaced.

“The orange outer layer is soft and comfortable in the hands, but the yellow layer underneath is a much stronger plastic than a dipped grip and is much more difficult to damage or penetrate, providing the user with an added level of confidence in the tool’s performance and making it a safer tool.”

In addition, Howell said standards and regulations are changing and affecting workplace safety. Recent changes to National Fire Protection Association regulations provide more specific working requirements and have helped electricians be more aware of work practices and tools that will allow them to be safe on the job.

“Product standards are also evolving,” he said. “We recently introduced the first and only line of insulated pliers that are UL classified. In addition to meeting the ASTM product specifications, these tools are independently certified by UL, giving end-users an added level of confidence that, when used properly, these tools will provide the performance and quality that is needed in these demanding applications.” EC

GRIFFIN, a construction and tools writer from Oklahoma City, can be reached at 405.748.5256 or [email protected].




About The Author

GRIFFIN, a construction journalist from Oklahoma City, can be reached at [email protected].





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