Simple Solutions for Lifting, Holding, and Handling Materials:

The Problem

On many construction sites, workers spend time lifting, carrying, holding, pushing, or pulling loads of material. Although it is common today to use mechanical devices for some of this work, a lot of materials are still handled manually. Sometimes it is not possible to use mechanical material handling devices due to site conditions.

If you lift and carry materials often or for long periods of time, there is constant stress on your back and shoulders. Eventually you may develop a serious muscle or joint injury. You are at risk if you often handle materials that are heavy and/or bulky, carry materials long distances, stoop downward to pick up heavy objects, or stretch upward while holding them. Your risk is higher if you twist your body when handling heavy items.

You may also develop an injury if you frequently push or pull heavy carts, dollies, or other transport equipment.

Injuries   Disorders

Below are some of the injuries you may develop when you do manual material handling.

Back. Low back pain, and more serious musculoskeletal injuries to the back, can occur suddenly or develop over a period of time. For example, sudden quick movements, especially while handling heavy objects, may lead immediately to painful muscle strains. These strains may develop into serious injuries when the muscles are not allowed to heal and are exposed to additional stress.

Your spine runs from the top of your neck down to your lower back. It is made up of many bones called vertebrae, one below another. Between the vertebrae are joints and discs. These give your back flexibility so it can move. The discs are flexible because they have a substance like jelly inside.

When you lift, bend forward, stretch upward, or stretch outward, your back muscles work harder and the ligaments (long fibers supporting the back muscles) flex and stretch. The discs get squeezed. As they are squeezed, they can press on different parts of the spine, including nerves. This can cause back pain. If you bend forward over and over for months or years, the discs are weakened, which may lead to disc rupture (or "herniation").

Twisting your body while bending puts even more pressure on the discs, especially when you are exerting force to lift, push, or pull objects.

Shoulder and neck. Carrying even light loads above your shoulders may quickly lead to tired and sore neck and shoulder muscles. The risk of developing a more serious neck or shoulder problem increases when you do this work frequently or for long periods of time. Carrying or resting heavy objects on your shoulders may stress the shoulder and neck muscles and cause injury where the load contacts your body.

The muscles in your shoulder are connected to your arm by tendons. Between the tendons and bones are small sacs of fluid called bursa. They lubricate the shoulder so it moves easily. Continual stress on your shoulder can cause the bursa to get squeezed, swollen, stiff, and inflamed (bursitis). Bursitis can make it painful, or even impossible, to raise your arm.

Continual stress on the shoulder can also cause the shoulder tendons to become inflamed, resulting in pain (tendinitis).

Another common condition is tension neck syndrome. This is a type of muscle strain that can cause neck stiffness, muscle spasms, and pain in the neck or radiating from the neck. It affects the trapezius muscle, a large, thin muscle that runs from the upper back through the shoulder area to the neck. You may notice a tender "knot" in this muscle as well as stiffness and pain.

Arms, hands, and wrists. If you carry heavy objects with hard sharp edges, they can dig into your skin and injure the soft tissues in your hands. Or, if you carry objects that are hard to grip and hold, they may force your hand or wrist into awkward, stressful positions and cause disorders like tendinitis or carpal tunnel syndrome.

Some Solutions

Manual material handling is still common in construction, but it is possible to change how you do it so it is easier on your body. Solutions are available that can reduce the level of stress on your back, shoulder, neck, and other parts of your body. 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 material handling tasks are explained in Tip Sheets #10-13.

General solutions for doing material handling 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. There are alternative materials that can be handled without requiring a lot of physical strength, an awkward posture, or repetitive motion. For example, half-weight bags of Portland cement and lightweight concrete masonry blocks are currently available in many areas. An individual construction worker or subcontractor usually cannot make a decision to switch materials. Certain changes may require the approval of the building owner, architect, engineer, or general contractor.

Change tools and/or equipment. You can buy or rent material handling devices for all aspects of construction. Devices include special round handles and cushioned grips for carrying heavy objects; powered and non-powered carts and dollies for indoor or outdoor use; rolling carts to move sheet materials, pipes, or conduit; and stands and jacks to hold materials during installation.

Mechanical, hydraulic, and vacuum lifts are available in a variety of sizes and styles. Some allow relatively easy positioning of components and materials.

Ergonomic Guidelines for Manual Material Handling (DHHS/NIOSH Publication No. 2007-131) describes many different types of material handling and transport equipment. This booklet can be accessed at www.cdc.gov/niosh/docs/2007-131/pdfs/2007-131.pdf.

In a few cases, cost and site conditions may restrict the use of such equipment.

Change work rules. For example, contractors can require that materials be stored at a convenient height off the ground and transported in most situations with mechanical devices. Improved planning of laydown areas and materials storage can minimize the number of times materials need to be moved.

Provide training and related programs. A policy of providing ergonomics training may help workers more quickly identify potential problems and find effective solutions.

Workplace exercise programs are popular in the construction industry. Although they may be a part of any effort to prevent muscle and joint disorders, exercise programs are not a substitute for other solutions. No studies have shown that they prevent injuries by themselves. Studies indicate only that exercise may have a short-term effect on reducing low back pain. There also is no evidence supporting the use of "body mechanics education" as an effective means to prevent back pain or serious back disorders. In edition, NIOSH does not recommend the use of back belts to prevent back injuries.

Training in the NIOSH lifting guidelines is especially important. NIOSH recommends that one person lift no more than 51 lbs. when the lifting can be done using the following "best practices":

• When you pick up or set down a load, don't reach more than 10 inches away from your body.
• Don't twist your body.
• Lift with your legs, not your back. Keep your back as straight as possible.
• Lift the load using a solid two-handed grip.

When lifting, holding, and positioning materials on a construction site you can't always follow these "best practices." In that case, the 51 lb. weight limit needs to be lowered. See the "Applications Manual for the Revised NIOSH Lifting Equation" (1997) for more information on how to use the guidelines. This information should be passed along to workers in training programs.

Page Content:

TIP SHEET #10 Lightweight Concrete Block

The Problem

A regular concrete block (also called a concrete masonry unit, or CMU) can weigh up to 50 pounds, depending on size. For masons and mason tenders, lifting and placing CMUs can cause fatigue and put strain on the low back, hands, and arms. If you do this work often, you may be at risk of a serious muscle or joint injury.

The risk depends on how many units you handle, how heavy they are, how often you work with them, how low they are stored, and how high you have to reach to place them on the course. You have even more risk if you twist your body when lifting or holding CMUs, or if you lift or hold them with one hand.

One Solution

Use lightweight concrete block. Units weigh 30-40% less than regular block without sacrificing strength or performance. Working with lightweight block can improve your output during the day and still decrease the total weight you lift. Less weight means you will be less tired and there will be less stress on your back, hands, and arms.

How It Works

The aggregate used for lightweight block is made from shale, clay, and/or slate. These materials are expanded in a rotary kiln at temperatures over 1000° C.

The block is structurally strong, stable, and durable, yet also light in weight and a good insulator. The block density is only 40-50 pounds per cubic foot. An ordinary block made from rock and sand has a density of 105-115 pounds per cubic foot. Lightweight block meets or exceeds the specifications required of regular heavy concrete block (American Society for Testing and Materials (ASTM) C 90 Standards Specifications for Load-bearing Concrete Masonry Units).

Benefits for the Worker and Employer

Laying lightweight CMUs reduces a worker's fatigue and lowers stress on the back and arm muscles. One study looked at how concrete block of different weights affects muscle stress. Masons built two walls. One used lightweight CMUs and the other regular CMUs. When workers built the lightweight CMU wall, they had less back and arm muscle stress. The difference was greatest when lifting the block to the top of high walls.

There can also be a gain in productivity. According to the National Concrete Masonry Association (NCMA), "lighter weight units resulted in higher productivity rates (other factors being equal)."

Approximate Cost

Lightweight block costs slightly more per unit than standard block. However, since masons and mason tenders can work faster and better, there should be a reduction in labor cost. This can account for up to 80% of the finished wall cost. Shipping and handling costs may be lower as well.

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: lightweight "concrete (or) masonry (or) block."
• 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. The Expanded Shale, Clay, and Slate Institute (ESCSI) in Salt Lake City, UT also has more information at www.escsi.org.

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TIP SHEET #11 Pre-Blended Mortar and Grout Bulk Delivery Systems

The Problem

When laborers mix mortar or grout in the traditional way, they have to lift heavy cement bags and shovel sand into the mixer. They usually repeat these motions over and over. Full cement bags weigh around 100 pounds, and workers may handle more than 100 bags a day.

Workers are at risk of back pain, shoulder pain, and even disabling muscle or joint injuries. The injuries can be the result of one-time accidents, but they usually develop over a long period of time.

Your risk of injury from lifting and shoveling depends on the weight of the load, the number of loads you lift, how long you do this work, and where the bags are placed. If you have to stoop down to a low pallet to pick up bags, or reach above your shoulders to dump them, your risk is especially high. You have even more risk if you twist your body while lifting.

One Solution

Use pre-blended mortar and grout mix for the job. This can be delivered to the site in bulk and doesn't require lifting bags or shoveling sand.

Bulk pre-blended mortar and grout can be used with conventional mixers or with European-style silo mixers. All dry ingredients are handled mechanically, with either a forklift or boom truck, eliminating the risk of injury due to manual handling.

How It Works

Pre-blended dry ingredients (including sand, pigments, and admixtures) are delivered to the site in 2,000 - 3,000 pound bulk bags. These are moved by forklift or boom truck over a funnel-shaped silo that straddles a conventional mortar mixer. The mix is released into the silo by pulling a hitch pin on the bag. To begin mixing, the mixer operator simply pulls a handle that opens the silo's discharge slide gate. The pre-blended material is gravity-fed from the silo directly into the mixer below. No electricity is needed. Only water needs to be added to produce the mortar and grout.

Benefits for the Worker and Employer

Laborers have less risk of disabling injuries due to constant manual lifting. Productivity is also increased because time-consuming manual handling of bags and sand is eliminated. One laborer may be able to tend two or three mixers.

With silo systems, bags don't break or leak. The product is more consistent because it is pre-mixed. There is no problem of sand freezing in winter. Silo dispensers can save space on congested jobsites and reduce material theft. Most silo systems are easily moved around the jobsite. Disposal of bags is not a problem since all bulk bags are removed by the supplier and either reused or recycled.

These systems do not eliminate the risk of silica dust exposure, but dust curtains are available to reduce the release of silica-containing dust. Specific safety procedures must be followed when loading the silo, climbing the silo's ladder, and moving the system.

Approximate Cost

Contractors estimate that using these systems adds about 7 - 8% to mortar cost. However, the additional cost may be offset by improvements in efficiency and productivity gains. Pre-blended mortar systems may not be cost-effective for smaller jobs. A supplier, however, should be able to help you determine if this product is appropriate for your work.

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: (silo or bulk) "delivery systems."
• 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.

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TIP SHEET #12 Skid Plates to Move Concrete-Filled Hoses

The Problem

Charged concrete hoses are heavy and pulling them takes a lot of strength. The latches on a hose may snag on rebar. Workers must sometimes bend down and
lift the hose to free it.

Pulling, lifting, and moving sections of hose can force your body into awkward positions and put strain on your lower back and knees. If you have to use jerking motions or twist your body while doing this work, there is even more strain on your back. Handling concrete hoses, especially for long periods of time, may cause fatigue, back pain, and even serious muscle or joint injuries.

One Solution

Skid plates (also known as "hose placing discs") may be useful when concrete boom pumps and other alternative ways of moving the concrete cannot be used. Skid plates are two-foot diameter concave metal disks that are placed under the hose couplings. They have a cradle to hold the hose and handles for carrying. They decrease the friction with the rebar matting underneath and make the hose easier to pull. They also prevent the latches on the hose from catching on the rebar.

How It Works

Laborers usually move concrete-filled hoses across rebar matting by pulling on ropes attached to the hose, or by using long metal hooked rods.

Skid plates slide more easily across the rebar matting, reducing the friction. Pulling is easier. Also, hose couplings do not catch on the rebar matting. This decreases the need for laborers to jerk the hose or bend over to free it.

From four to six skid plates should be used near the pour end of the hose. They are most effective when the hose is secured to each plate. You can fasten the hose to a plate with rebar tying wire or rubber bungee cords. Both can quickly be removed when necessary. Using unsecured skid plates may lead to more bending, awkward positions, and back strain.

Benefits for the Worker and Employer

At least one study has found that using skid plates secured to the hose can reduce stress to the low back that otherwise would increase the chance of developing a serious injury.
Use of secured skid plates does not result in loss of productivity. It takes only moments to place skid plates under hoses and secure them. If workers are less fatigued from pulling heavy hoses, productivity may actually increase.

There are a few drawbacks. For example, it is still possible for skid plates to catch on Nelson studs (4" tall steel rods welded to the subflooring to reinforce the concrete). Skid plates reduce the physical stress of pulling a hose, but they don't get rid of it. The plates should be used only when the charged hose cannot be moved with a boom, crane, or motorized concrete placement equipment.

Approximate Cost

Prices run about $200-300 per plate.

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: "concrete" + "hose placing disc."
• 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.

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TIP SHEET #13 Vacuum Lifters forWindows and Sheet Materials

The Problem

Manually installing large windows and sheet materials requires workers to handle heavy and bulky objects. You may need to lift and carry them some distance to the installation site. When installing them, you may have to use a lot of strength to hold them while they are placed and secured.

This work puts stress on your back and shoulders, which can lead to serious muscle and joint injuries. Injuries can be even more serious when you have to work in awkward positions or hold materials for a long period of time. Manually placing windows and sheet materials may also lead to hand injuries.

One Solution

Use vacuum lifters to install windows and other flat panels. Vacuum lifters eliminate the need to manually lift and position heavy and awkward materials.

A vacuum lifter can be attached to a forklift, or to a small counter-balanced crane built in the shop. It can also be attached to a larger crane for outdoor work.

How It Works

There are both non-powered and powered vacuum lifter systems available with load capacities from 375 - 1400 pounds. Non-powered "hand cup" systems lift and carry
the load using manually-operated, pump style vacuum cups attached to a specially-designed frame. Some of these frames permit loads to be rotated and tilted. In some cases, the cups can be removed from the frame so they can be used individually for lifting and carrying.

Although some contractors use manual systems, a more typical system is a powered lifter using cups with a cord-free 12-volt vacuum pump. "Below-the-hook" powered vacuum lifters are a little more expensive but feature rotation and tilt.

Benefits for the Worker and Employer

Large window units and other panels can be installed without the usual physical stress that comes with lifting, carrying, holding, and positioning heavy objects. Using lifters will help reduce the possibility that a worker will develop a muscle or joint injury.

A vacuum lifter also keeps the fingers and arms from being caught in pinch points when positioning and setting the window or panel.

There should be a gain in productivity, since workers will be less fatigued and able to install more windows or panels. There may also be less damage to windows and other materials.

Approximate Cost

Manually-operated "hand cup" frames featuring rotation and tilt cost around $1,200. You will spend about $300 total for four 9-inch pump-style vacuum cups to use with them.

A basic four-cup DC-powered lifter costs around $2,500. Below-the-hook vacuum lifters are available with various options and configurations, ranging from $3,000 - 7,000.

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: "vacuum lifters."
• 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.

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