Simple Solutions for Hand-Intensive Work:
The Problem
Construction workers usually spend a lot of time gripping tools or materials with one or both
hands. This work can put stress on your hand, wrist, and/or elbow, causing discomfort and pain.
Eventually you may develop a serious muscle or joint injury. Your ability to use your hands and
wrists may be reduced, and you may even become permanently disabled.
You are at risk of injury if you often use a forceful grip on tools, bend your wrist when using
them, or move your wrist rapidly or repetitively. Injuries also can result if you frequently hold
vibrating tools, or if tool handles that are hard or sharp often press into your hand, wrist, or arm.
Gripping tools and other materials can be physically demanding, repetitive work. It may injure
the muscles, tendons, and cartilage of your hand, wrist, and elbow. Damage to the nerves and blood
vessels can also occur.
If you experience soreness or pain, and continue doing the work without allowing your muscles
and tendons to rest and heal, the pain may get worse and you may eventually develop a serious disorder.
 Injuries & Disorders
Below are some of the injuries you may develop when you do hand-intensive work.
Tendinitis. Most of the muscles that move your hand and fingers are actually in your forearm. These muscles
are connected to the hand and fingers by tendons, which are like cords passing through your wrist.
You can strain the tendons in your wrist if you frequently exert strong force with your hand, bend your wrist while working, or repeat the same wrist movements over and over. If this strain continues over time,
you may develop tendinitis. Tendinitis makes it painful to use your hand, especially to grasp things.
Carpal tunnel syndrome. The carpal tunnel is an area in your wrist that is surrounded by bone and tissue. A nerve and several tendons pass through this tunnel. If you have tendinitis and your tendons swell, there is less room in the tunnel for the nerve. When the nerve is squeezed this way, the condition is called carpal tunnel syndrome. It often
leads to pain, tingling, or numbness in your hand, wrist, or arm. These symptoms are often felt at night.
If left untreated, carpal tunnel syndrome can weaken the hand and make it very difficult to grasp things or even use that hand at all.
 Trigger finger. Repeated pressure on a finger (such as when using the trigger on a power tool) may strain the tendon running to that finger, as well as the tendon covering This may cause discomfort or pain.
Epicondylitis. Forceful twisting motions may cause strain on your elbow tendons,  causing discomfort or pain. This condition is called epicondylitis, also known as tennis elbow.
Hand-arm vibration syndrome (HAVS). Operating vibrating tools like needle guns, chipping hammers, and rotary hammer drills may lead to finger discoloration, tingling, and numbness. Gangrene is possible in the most severe cases.
Some Solutions
Hand-intensive work cannot be eliminated from construction, but it is possible to change how you do it so the work is easier on your body. Solutions are available that can reduce the level of stress on your hands, wrists, and arms. They may also reduce how often and how long your body is subjected to this stress.
Many of the solutions can also eliminate other potential safety hazards and increase productivity.
The type of task and the site conditions will determine which solutions are best for you. A few possible solutions for specific hand-intensive tasks are explained in Tip Sheets #14-20.
General solutions for doing hand-intensive work with less risk of injury include:
Change materials or work processes. One of the most effective solutions may be to use materials, building components, or work methods that are less labor-intensive. For example, use lock nuts or button nuts on all-thread systems to reduce repeated hand-arm twisting and turning. An individual construction worker or subcontractor usually cannot make a decision like this. Certain
changes may require the approval of the building owner, architect, engineer, or general contractor.
Change tools and/or equipment. If the work requires frequent intensive hand activity, you can often substitute a power tool for a manual tool. This will reduce the amount of hand force needed and the number of repeated movements, especially twisting motions. You will get the job done with less effort.
You can also use ergonomically improved tools. Select a tool that comes with a power grip, or add a power grip to existing tools. Compressible foam can be used to wrap a narrow tool handle and improve the grip. Some power tools have a large trigger that can be operated with multiple fingers so you don't constantly put all the stress on one finger.
Also, look for power tools that meet stricter European hand-arm vibration requirements.
Choose the right tool for the job. For example, snips and other tools are available with features such as offset handles that can help keep your wrist straight on some types of jobs. Also, never use your hand to hammer or pound anything into place.
In a few cases, cost and site conditions may restrict the use of ergonomically improved tools.
Change work rules and provide training. Contractors can encourage the use of equipment like ergonomic tools. Site rules can limit the amount of time that workers do hand-intensive jobs without a break. A policy of providing ergonomics training may help workers more quickly identify potential problems and find effective solutions.
Page Content:
TIP SHEET #14 Ergonomic Hand Tools
TIP SHEET #15 Easy-Hold Glove for Mud Pans
TIP SHEET #16 Power Caulking Guns
TIP SHEET #17 Reduced Vibration Power Tools
TIP SHEET #18 Power Cleaning and Reaming with a Brush
TIP SHEET #19 Snips for Cutting Sheet Metal
TIP SHEET #20 Quick-Threading Lock Nuts
TIP SHEET #14 Ergonomic Hand Tools
The Problem
Using a conventional hand tool over and over can lead to muscle strain or even a serious injury like carpal tunnel syndrome or tendinitis. Using the wrong tool, or using a tool the wrong way, can strain your hand, wrist, forearm, shoulder, and neck.
One Solution
Use an "ergonomic" tool that fits the job. Many new tools are available that may help prevent muscle and joint injuries. However, some new tools advertised as "ergonomic" have not been carefully designed.
A tool can be considered "ergonomic" when it fits the task you do, fits your hand, allows a good grip, takes less effort, does not require you to work in an awkward position, does not dig into your fingers or hand, and is comfortable and effective. Remember that a tool designed for one task may put more stress on the hand or wrist when used for a different task. For example, needle-nose pliers work well for crimping electrical wire but should not be used for twisting.
How It Works
Here are some tips for selecting an ergonomic hand tool. Handle. The handle should be non-slip, coated with soft material, and not have sharp edges. You may want to add a soft sleeve to the handle for a better and more comfortable grip. However, make sure the sleeve doesn't increase the handle diameter to more than
two inches, which would make it harder to grip. Make sure the sleeve does not slip on the handle. If your task requires high force, pick a tool with a handle longer than the widest part of your hand. The end of the handle shouldn't press continually on your palm. Avoid tools with finger grooves on the grip. Grooves that do not fit your hand can put more pressure on your fingers, which can injure the finger tendons.
Wrist position. Pick a tool that keeps your wrist straight when you use it. A tool with a bent handle may work best if you are applying a horizontal force (in the same direction as your straight forearm and wrist). A tool with a straight handle may work best if you are applying an upward or downward force.
Handle diameter. For single-handle tools, if the task requires high force, handle diameter should be between 1-1/4 inches and 2 inches. For low-force tasks requiring precision or accuracy, handle diameter should be between 1/4 inch and 1/2 inch.
For double-handle tools, grip span for high-force tasks should be at least 2 inches when closed and no more than 3-1/2 inches when fully open. For low-force tasks requiring precision or accuracy, grip span should be at least 1 inch when closed and no more than 3 inches when fully open.
Pinching, gripping, or cutting tools. Choose a tool with a spring-loaded handle that automatically returns to an open position. If continuous high force is necessary, consider using a clamp, a grip, or locking pliers.
Benefits for the Worker and Employer
When you choose a tool that fits your task, you reduce your chance of developing an injury. You may also get the job done quicker and improve the quality of your work.
Approximate Cost
Many tool manufacturers now produce ergonomically improved hand tools. Often these are no more expensive than non-ergonomic tools.
For More Information
- Products related to this solution are described at www.cpwr.com/simple.html. Products also may be found on the internet using the following search terms: (type of tool) + "ergonomically designed."
- Local contractor tool and equipment suppliers or rental companies may be another source of information on products.
- For general information on this solution, check www.cpwrconstructionsolutions.org and
www.elcosh.org. Other good information is available at:
Page Content
TIP SHEET #15 Easy-Hold Glove for Mud Pans
 The Problem
A mud pan full of drywall compound can weigh more than five pounds. Continuously gripping the pan
can put a lot of stress on your hand, wrist, and forearm. If the mud pan is too wide for your hand,
you have to squeeze its sides to hold it, putting more strain on your forearm muscles.
The smooth sides and bottom on a mud pan make it hard to grip with bare hands. Because of its weight,
size, and smoothness, you must use a lot of hand force to hold the pan.
All these types of strain can tire your hand, wrist, arm, and forearm. If you do drywall work often and
for long periods of time, the strain may lead to serious injuries.
 One Solution
Use an easy-hold glove attached to the mud pan, which you can make yourself. The glove cuts down on the hand strength required
to grip the pan. With the glove, all you need to do is balance the pan.
 How It Works
The glove is bolted to the pan with a swivel mount. A bolt is welded to the bottom of the pan, and held by a nut inside the glove. This holds the pan in place.
You never have to squeeze the pan. Because of the swivel mount, you can spin the pan in your hand as needed. The glove fits snugly on your hand. A Velcro® strap holds it in place. The glove spreads the weight of the pan over your whole hand.
You need only to open your hand wide to balance the pan. The pan swivels easily.
Benefits for the Worker and Employer
Finishers who used the easy-hold glove liked it and said it was great for long periods of coating drywall. They said that it cut down on their long-term fatigue and pain.
Researchers found that wearing the glove led to a 25% reduction in grip force needed to hold the pan.
There are some drawbacks. Finishers said that it takes time to put the glove on and take it off. Other tasks,
such as putting up tape, cannot be done while wearing the glove.
Approximate Cost
If you make your own easy-hold glove (see section below), the cost of materials is low.
You can begin with a fingerless bicycle glove, available for $5-20.
To make your own: Use a tight-fitting glove with a stiff palm, such as a fingerless bicycle glove. Make sure the glove is not so tight that it affects blood circulation in your hand. But if the glove is too loose, you will end up gripping the mud pan tighter. A glove without fingers lets you use your own fingers more easily. However, it also makes
the glove a little harder to take off, because the finger holes can get caught on your knuckles.
Fix the head of a small bolt to the bottom of the mud pan. You can weld the bolt or "glue" it using a metal-to-metal adhesive. Place a large (up to two-inch) washer on the bolt. Punch the bolt through the palm of the glove. Inside the glove, place another large washer over the bolt that sticks through. Tighten a lock nut over the bolt inside the glove. Cut off any part of the bolt that sticks above the nut and sand the bolt smooth. If the bolt
still presses on the palm of your hand inside the glove, cover it with duct tape or another material.
For More Information
Page Content TIP SHEET #16 Power Caulking Guns
The Problem
Using a non-powered caulking gun requires high hand forces to pull the trigger. If you  use these guns often and for long periods of time, you are at risk of stressing the soft tissues in your hand, wrist, and forearm. This can lead to serious muscle or joint injuries.
The more pressure your gun requires to pull the trigger (low mechanical advantage), the higher your chance of injury. You may have to use even more force when you apply thicker sealant material. If you have to bend your wrist or twist your forearm when pulling the trigger, you also increase your chance of injury.
Your chance of developing an injury increases if the gun you use has sharp edges or grooves on the trigger, or has a wide span between the trigger and the grip, forcing you to stretch your hand.
One Solution
Use a power caulking gun. These guns may be powered by a battery or may be pneumatic
(powered by compressed air). With a power caulking gun you won't need to pull the trigger to apply
the caulk or sealant. This will reduce the stress to your fingers, hand, and forearm.
How It Works
A battery (cordless gun) or compressed air (pneumatic gun) provides the power to force the caulk from the gun. Some guns have a variable speed control to manage sealant flow. You do need access to a power source. This may be an electrical outlet or generator to charge the batteries in a cordless gun, or an air compressor to power a pneumatic gun. When you use a pneumatic gun, the hose may produce some resistance (or "drag") on the tool, possibly increasing the grip force necessary.
Cordless guns are available for tube, sausage, and bulk caulks. A 12-volt or higher cordless gun will produce 600+ lbs. of thrust force. Pneumatic guns will handle sausage and bulk caulks.
Another device available is a caulk-dispensing adapter that can be used with a cordless drill or variable speed AC drill. These adapters are available for 10 oz. and 30 oz. caulk cartridges.
Benefits for the Worker and Employer
Use of power caulking guns should result in less soft tissue fatigue, discomfort, and injury. Although power caulking guns are heavier than non-powered guns, they do not require high hand forces to get the caulk out of the gun.
One minor drawback is that pneumatic caulking guns are tethered to the air compressor with a hose, and the hose must be moved along with the gun.
Approximate Cost
Cordless caulking guns, with 12-volt battery and charger, range from $200-300, depending on size. Pneumatic caulking guns start around $20. Caulking attachments for cordless drills cost $45-50. For More Information
- Products related to this solution are described at www.cpwr.com/simple.html. Products also may be
found on the internet using the following search terms:
- Cordless Caulking Guns: "cordless caulk (or caulking) gun"
- Pneumatic Caulking Guns: "pneumatic caulk (or caulking) gun"
- Caulk-Dispensing Attachments for Drills: "power caulker drill attachment"
- Local contractor tool and equipment suppliers or rental companies may be another source of information on products.
- For general information on this solution, check www.cpwrconstructionsolutions.org and www.elcosh.org.
Page Content
TIP SHEET #17 Reduced Vibration Power Tools
 The Problem
From chainsaws to impact drills to soil compactors, some hand-held power tools can produce a lot of vibration. Certain tools generate vibration levels so high that they can damage the blood vessels and nerves in your hands.
The problem usually begins with numbness and tingling in your hands. After you have been exposed to vibration for a while, your fingertips may become discolored or white, especially when they get cold. You may also lose grip strength. In extreme cases, gangrene is possible. This injury is sometimes called "white finger" or "hand-arm vibration syndrome" (HAVS).
You are at greater risk of developing a vibration-related injury if you use vibrating power tools often or for long periods of time. These injuries can be prevented, but there is no cure once you have them.
 One Solution
Use reduced vibration power tools. Many tools are now available that are designed to produce less vibration. They should always be used with full-fingered anti-vibration gloves that are certified to meet International
Organization for Standardization (ISO) vibration standards (ISO 10819). Gloves that are not ISO-certified may not reduce vibration adequately, even when using a tool designed for low vibration.
Always keep your hands warm when using any vibrating tool, and use as light a hand grip as possible. Using a lighter grip helps reduce your exposure to vibration.
How It Works
Many manufacturers now offer reduced vibration tools. Although there are no regulations limiting vibration exposure in the U.S., there are limits in Europe and companies produce tools for both markets. The European limits have been adopted by the American National Standards Institute (ANSI) as recommended exposure limits (S2.70-2006).
The possible harm caused by operating a vibrating tool is related to the level of vibration and the amount of time the tool is used. The higher the vibration level, the shorter the time the tool can be used safely. In 2002, the European Union limited ISO frequency-weighted vibration exposure to an average of 5 meters per second per second (m/s2) over any 8-hour period. For example, use of a tool with a high level of vibration (10 m/s2) would be limited to a shorter period (2 hours per day). For text of the European regulation search for "Directive 2002/44/EC" in any Internet search engine.
The National Institute for Working Life in Sweden lists vibration levels for hundreds of specific power tools on the web (go to http://vibration.niwl.se/eng). Vibration measurements are approximate, not absolute. They can vary depending on how the vibration is measured, how the tool is being used, and the condition of the tool. Also check users' manuals for vibration information.
If you know the vibration level of a tool, you can determine how much time you can safely use it. (This is called "trigger time.") There are several vibration exposure calculators on the web. If you enter a tool's vibration level (in m/s2) the calculator will tell you the trigger time. Vibration exposure calculators can be used to help determine whether the tool you use produces too much vibration. Calculators can be found online by using the following search terms: "vibration exposure calculator."
Benefits for the Worker and Employer
Reduced vibration tools allows workers more "trigger time" with less risk of injury. Where trigger time limits are enforced by the employer, using reduced vibration tools may also increase productivity. Using anti-vibration gloves alone may not eliminate exposure to all harmful vibration.
Approximate Cost
Reduced vibration power tools are available for purchase and rental. Contact the tool manufacturer or representative for prices. Anti-vibration work gloves usually cost $40-50.
For More Information
- Products related to this solution are described at www.cpwr.com/simple.html. Products also may be found on the internet using the following search terms: "low vibration tools."
- Local contractor tool and equipment suppliers or rental companies may be another source of information on products.
- For general information on this solution, check www.cpwrconstructionsolutions.org and
www.elcosh.org. Information, including additional vibration exposure calculators, is also available from the Canadian Center for Occupational Health and Safety (CCOHS) at www.ccohs.ca.
Page Content
TIP SHEET #18 Power Cleaning and Reaming with a Brush
The Problem
Frequent use of a wire brush to clean or ream pipes, grates, and other building materials can strain your hands, wrists, forearms, and elbows. Using the brush may be light work, but you must bend your wrist and use fast pulling, pushing, or rotating motions. If you do this work often, you can be at risk of a serious muscle or joint injury.
Your chance of developing a serious injury increases when you have to apply high hand force to the brush or use a pinch grip to hold it. If you wear loose-fitting, thick gloves, the brush may be harder to hold and require more force.
One Solution
Place the wire brush in the chuck of a battery-powered or corded screw gun or screwdriver. The power tool will eliminate the repeated hand, wrist, and forearm motions and may improve your grip.
How It Works
The power tool rotates the brush for you. Choose a power tool with a soft, non-slip handle (plastic or rubber covering). The handle should be large enough to fit your whole hand. It should not have sharp edges or ridges. You will need less hand strength to grip this type of handle than to grip a brush. The smaller handles on manual wire brushes must be gripped with a few fingers, rather than with the full hand. This requires more muscle force.
There will be less localized pressure on your hand because the handle won't dig into your skin. There also will be fewer rapid movements of your hand, wrist, and forearm. The rotation of the power tool replaces the motions necessary with the manual wire brush.
Many power tools can help keep your wrist straight. Some have handles that change from in-line to pistol-grip (two-way handles). These prevent awkward wrist positions because the tool bends-not your wrist. Or, depending on the location of the work, you can use a power tool with either a pistol grip or in-line handle, whichever best reduces wrist bending in each situation.
Benefits for the Worker and Employer
Using a power tool with the wire brush should result in less strain on your hand, wrist, forearm, and elbow. It will also improve productivity because the work is faster than using a brush by hand.
You do need access to a power source. This may be an electrical outlet or generator to run a corded tool or to charge the batteries in a cordless one.
Approximate Cost
Professional-quality tools can be purchased at most hardware, home improvement, and commercial building supply stores. Prices vary and you should shop around before purchasing one. If you plan to use the tool often, consider purchasing a heavy-duty contractor or professional-quality model. For professional models, a corded screw gun runs $125-150. A battery-powered screw gun (14.4-18 volts) is $180-250. A battery-powered screwdriver (2.4-3.4 volts) is $100-125. Wire brushes are available as accessories from many power tool manufacturers.
For More Information
Page Content
TIP SHEET #19 Snips for Cutting Sheet Metal
 The Problem
Cutting sheet metal with snips takes a lot of hand force. You often need to work with your wrist in an awkward position. If you do this work often or for long periods of time, you may experience hand or wrist pain. Eventually you may develop a serious injury.
Using the wrong snip for the job increases your chance of injury. Snips come in many shapes and sizes. Manufacturers produce different snips for specific tasks and specific workers. If you use left-cut snips to do a right-cut task, your hand and wrist will be in a stressful position and you will have to use more force. If you cut sheet metal that is thicker than the snip manufacturer recommends, more force will also be necessary. If you use dull snips, they will make your work even harder.
One Solution
Use the right size and type of snip for the task. New types of snips are available that may fit your hand better, keep your wrist straighter, and require less hand force.
Any snip you use should be sharp and tight. Do not use dull or damaged snips. Where necessary use compound snips, which provide much more power. Some compound snips will increase your hand strength by 12 times. Electric snips are usually best when you need to make many cuts.
Most snips are made for cutting soft metal only. For hard metal, you should use other cutting tools designed for that purpose.
How It Works
Improvements found in the newer snips include less space between the handles, soft grips and curved handles. Using a curved handle can help keep your wrist straight. A soft grip lowers the pressure on your hand and fingers. When the space between handles is less, you may be able to get a better grip on the tool. An upright snip can help keep your wrist straighter when working in confined areas or overhead.
No pair of snips will work well for every task. Decide what the job requires and select the correct snips. Manufacturers make specific snips for left and right cuts, straight cuts, and wide or tight curved cuts. There are specific snips for different gauges of sheet metal. Different snips are made to fit left- and right-handed workers.
Pay attention to the manufacturer's specifications. Manufacturers color-code snip handles for the type of cut they make- yellow for straight, green for right, and red for left. Use snips that fit both your hand and the job you do, either left-handed or right-handed. Always wear eye protection when using snips.
Benefits for the Worker and Employer
Choosing the correct snips should make the job easier. Your hand and wrist should be less tired, and less likely to be injured. You also should be able to get the job done faster.
Approximate Cost
The best snip for the job should not cost much more than other snips. Newer snips are often between $10-40.
For More Information
- Products related to this solution are described at www.cpwr.com/simple.html. Products also may be
found on the internet using the following search terms: "aviation snips" + "ergonomic design."
- Local contractor tool and equipment suppliers or rental companies may be another source of
information on products.
- For general information on this solution, check www.cpwrconstructionsolutions.org and
www.elcosh.org.
Page Content
TIP SHEET #20 Quick-Threading Lock Nuts
 The Problem
When you tighten a standard lock nut around the thread on a long rod, you have to twist your hand, wrist, and forearm over and over. Making these twisting movements can strain the muscles and tendons in your hand, wrist, and elbow. The strain can become more serious if you do this work a lot and you repeat the same movements for a long period of time. You can eventually develop pain and even a serious injury.
Your chance of injury depends on the amount of finger pressure you use to hold the nut, the distance the nut is threaded, and the number of nuts threaded. Working in positions where you have to reach above your shoulders to thread the nut increases your chance of injury.
One Solution
Use a quick-threading lock nut. Depending on the type of nut, these can either snap onto an all-thread rod at any position, or slide up and down the rod freely. They eliminate the repeated hand, wrist, forearm, and elbow twisting. They can also reduce the time you spend working above your shoulders because they go on faster.
How It Works
There are two types of quick-threading lock nuts-two piece lock nuts and button lock nuts .
When using the two piece lock nut, you twist the two sections of the nut apart until the slot is open, then place the nut on the all-thread rod where you need it. Then twist the two sections together again until the slot is closed and the sections are snug against each other. Finally, tighten the nut with a wrench until the openings on the two sections face in opposite directions.
When using the button lock nut, you first push the button to loosen the nut from the thread. Then slide the nut to the spot you want. Let go of the button to make the nut re-connect with the thread. Then tighten it as you would any nut.
Benefits for the Worker and Employer
Using quick-threading lock nuts should reduce the strain on your hand, wrist, and forearm. It should therefore lessen the chance of pain and musculoskeletal injury. Because you spend less time working above your shoulders, there is also less overall strain on your shoulders, neck, and back during a shift.
In addition, these nuts should lead to a gain in productivity because they take less time. They make certain kinds of work much easier, such as threading nuts in locations that are difficult to access. Quick-threading lock nuts may not be appropriate for all jobs, and their use may require the approval of the building owner, architect, engineer, or general contractor.
Approximate Cost
The two piece lock nuts start at $2-3 each, depending on diameter. Metric sizes are available. The button lock nuts start at approximately $6 each.
For More Information
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Hand–Intensive Work
