When people think about hand safety they often think about gloves. And rightly so: gloves help prevent cuts and scrapes, keep out chemicals and protect against extreme temperatures. Hand safety doesn’t just involve hazards related to the skin, though. Ergonomics play a significant role in hand safety over time, and those kinds of injuries don’t happen in one day. Health problems like tendonitis, carpal tunnel syndrome and other muscle strains are the result of repetitive motions. These injuries can be prevented at industrial and construction worksites, though, by selecting appropriate hand tools. Not having the right tools, organized with a good piece of tool foam, close to hand, often causes excessive motion. Bad layout of the work area, also can result in excess small motions. While each movement may not seem like much, these extra motions repeated day after day, can lead to injuries.
Hand Tools and Ergonomics
According to the National Institute for Occupational Safety and Health (NIOSH), workers should select tools that can be used with the least amount of force, repeated movement and awkward positioning possible to perform a task. Over time, things like using a tool at the wrong angle or lifting a heavy tool repeatedly can get employees into trouble and lead to what are called musculoskeletal disorders.
Symptoms of musculoskeletal disorders in the hands and arms include decreased movement, decreased grip strength, muscle fatigue, tingling, joint swelling, soreness, numbness, changes in skin color and pain, and any workers experiencing these symptoms should discuss their current work behaviors with a doctor. To prevent these types of problems, it’s essential to select the right tools for the job.
So which tool is the right tool? An ergonomic one.
An ergonomic tool, NIOSH explains, is one that fits both your hand and the task you are performing. You shouldn’t use a tool for a task it’s not designed for, nor should you use a tool too big or too small for your hand. Either can cause you to strain muscles in unhealthy ways.
Before you run to the store and start picking up tools to see which feels best in your hand, there are a few key things to consider.
How Will the Tool Be Used?
Tools serve many purposes in the workplace, and specific tools are designed to accomplish specific tasks. Just because you have a heavy wrench on hand and can’t find a hammer doesn’t mean you should use the wrench to pound something. That may be an obvious example, but consider a more common problem: sometimes you may have the incorrect size tool available, and using it could require you to hold your arm at an odd angle.
The point is you should know what tools a job requires and obtain those tools to get the job done. Common tools include striking tools (like hammers or mallets), driving tools (like screwdrivers or wrenches), cutting/pinching tools (like pliers) and hammered tools (like chisels).
Another consideration when choosing a tool for a task is how that tool will be held. Certain tasks require more force than others, which means tool users will employ different hand positions.
A power grip, which is when a person wraps all fingers around the handle of a tool, provides the most force. Think of the way someone grips a hammer to strike a nail.
A pinch grip (sometimes called a precision grip), on the other hand, is used when a task requires small, accurate movements. The tool user holds the tool between the thumb and fingertips. Think of the way someone grips a screwdriver to remove a screw from a small space.
The type of grip a person will use with a tool helps determine what size tool is necessary for a job, which we will return to in a bit.
A tool must fit the job and it also must fit your hand. To achieve the best fit possible for your hand, one option is to learn your actual hand size. ChooseHandSafety.org, an informational website run by the Center for Construction Research and Training (CPWR), provides information about how to measure the size of your hand, your grip and your palm. (The size of your grip is probably the least obvious here; put simply, if you make the okay sign with your hand, your grip size is the diameter of the circle made by your thumb and index finger.)
CPWR also suggests workers can experiment with tools by using them for a while, then adding tape to a tool’s handle to see if the larger size is more comfortable and removing tape if necessary.
What to Look for in a Tool
Non-electric tools like hammers, trowels and brushes may seem simple, but you should consider a number of factors before selecting a tool for a job.
The diameter of a tool’s handle is one of the most important characteristics of a tool because a proper diameter will give you the best grip. For single-handle tools (most tools), NIOSH recommends a handle diameter of 1-¼ inches to 2 inches for tools that will require a power grip and ¼ to ½ inch for tools that will require precision grips. (For even more precise information about the measurements needed for your hand size, visit Choose Hand Safety).
Some tools like pliers, cutters or tweezers have two handles so they are referred to as double-handle tools. If you will use a power grip to complete a task with a double-handle tool, the tool should have an open grip span of 3-½ inches or less and a closed grip span of 2 inches of greater. For tasks that will use the pinch grip, the grip span should be slightly smaller: 3 inches or less when open and 1 inch or more when closed. Take a look at NIOSH’s Guide to Selecting Hand Tools to see more detailed information about these measurements.
As a general rule, you will always want to select a tool whose handle is long enough that its end won’t press into your palm. This typically means the handle must be at least four to six inches long.
A bent wrist can over time become an injured wrist, so always choose tools that allow you to keep your wrist straight while you use them. Sometimes this means the handle will be straight, but other times this might mean the handle is at an angle. For example, if you want to apply force in the same direction as your straight forearm, a bent handle would work better than a straight one.
Also consider whether you will need to use the tool in a small space. If you were using a screwdriver to work inside of a machine, for example, a long handle could get in the way and require you to bend your arm at an angle that is not ergonomic.
When it comes to a tool’s weight, lighter is usually better. At first glance, it might seem like a heavy tool could get the job done faster, but oftentimes a heavy tool will cause worker fatigue sooner and can place extra strain on muscles. Consequently, it’s important to select the lightest tool possible that can still effectively accomplish the task at hand.
Keep in mind that the listed weight of a tool may not include the weight of a handle.
Tool handles are made from a variety of materials including metal, wood and fiberglass. Each material has benefits, but as a user you should think about how the material could impact your safety.
When using a heavier tool like a hammer, the handle will vibrate each time you strike something. Over time, this can cause nerve damage in the hands and wrist. Wood and fiberglass tend to vibrate less than metal, so those materials will likely keep your hands safer when using striking tools.
Additionally, some materials provide a better grip than others, which prevents a tool from slipping out of your hand. Some handles also have anti-slip materials added to them, so look for those features when dealing with tools like hammers or mallets.
Adjusting Tools to Fit Your Hand
Choose Hand Safety suggests tools can be adjusted to make them more ergonomic. Tool sleeves can be added when handles are too small. If a handle is too big, it’s sometimes possible to replace the handle. Wood handles can also be sanded down to make them smaller (although if you go this route, make sure your adjustments to the tool won’t make it more likely to break during use).
Gloves can also help make a tool that’s too small for your hand fit better, but you should assess whether the gloves limit your ability to perform required tasks. Some tasks also require PPE like gloves, and in those cases users should always select tools based on the size their gloved hands.
For more information about selecting hand tools and the ergonomics of hand safety, visit ChooseHandSafety.org or NIOSH.
Need somewhere to store your new tools? Try using foam tool organizers to keep your workspace safe and organized.