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The impact of ergonomics on foundry operations.

The definition of ergonomics is rapidly expanding to encompass more than just the commonly accepted definition of designing products for user comfort.

A growing awareness of the seriousness of low back pain and repetitive motion disorders-and recent actions by the Occupational Safety and Health Administration (OSHA)-have convinced many foundry managers that corrective ergonomics actions contribute to improved worker safety, enhanced productivity and lower workers' compensation costs.

OSHA estimates that ergonomics-related injuries cost American industry more than $100 billion annually by disabling almost 19 million workers. This represents a significant increase in claims over the past 10 years, as musculoskeletal injuries have risen from 18 to 52% of all recorded occupational injuries and illnesses. Back injuries alone comprise 40% of all workers' compensation costs., Injury Groups

Musculoskeletal injuries are broken down into two distinct groups, both potentially affecting foundry workers:

* Low back pain (LBP)-these injuries

arise from improper lifting, stretching,

pulling or pushing, poor posture and

falling. Typical workplace activities

that are associated with LBP include

material handling or long periods of

improper sitting or standing.

* Cumulative trauma disorders

(CTDs)-upper extremity CTDS are

seen in jobs that involve repetitive

motion, forceful exertion, vibration

or poor posture. Sources may vary

from computer keyboarding to hand

tools. CTD usually affects the fingers,

wrists, elbows, arms, shoulders and


In 1991, OSHA took the first step toward regulating ergonomics conditions in the plant by issuing a booklet of guidelines for the red meat industry called "Ergonomics Program Management Guidelines for Meatpacking Plants." (The book is available free by writing to: OSHA Publications, Room N3101, Frances Perkins Building, 200 Constitution Avenue NW, Washington, D.C. 20210. Include a self-addressed mailing label.)

Development of the booklet and related ergonomics programs resulted from the meatpacking industry's history of problems with CTDS, which culminated in Senate labor committee hearings in 1988. OSHA proposed fining one large meatpacker a total of $5.69 million for not providing a safe and healthful workplace in relation to ergonomic concerns; the company, the union and OSHA finally reduced the fine to $975,000. In addition, another plant reduced a proposed OSHA fine from $4.33 million to $990,000, plus a $260,000 awards grant for the National Institute for Occupational Safety and Health (NIOSH).(2)

The guidelines outlined in OSHA'S new booklet are not mandatory, but the fact that OSHA has comprehensively addressed the problem of ergonomic injuries for the first time indicates the agency will be monitoring workplace related CTDS in the future. Indeed, OSHA will be working closely with the meatpacking industry to study ways to reduce the incidence of CTDS.

In particular, OSHA allows meatpacking companies to sign agreements to reduce ergonomic hazards. OSHA then responds to complaints by conducting inspections of the signatory plants, but these plants would not be cited or penalized for ergonomic hazards.

Workplace Controls

To correct ergonomics hazards in the workplace, OSHA recommends four types of solutions:

* Engineering Controls, in which at-risk jobs are altered to lower the risk of injury. Typical solutions involve redesigned workstations, new processes,

* work methods and tool designs.

Work Practice Controls, in which at-risk workers and at-risk jobs are matched. Solutions may include new employee training, annual retraining, job redistribution, task modifications and use of the proper manual techniques.

Administrative Controls, in which the at-risk workers are excluded from, or limited in their time on, problem jobs. Management actions to impose administrative controls include reducing the duration, frequency and severity of motions; slowing production rates; limiting overtime; preemployment and preplacement medical screening, providing adequate rest pauses; increasing the number of workers assigned to a particular task; rotating work among jobs; and maintaining the working condition of tools and equipment. Personal Protective Equipment, which involves, for example, the proper fit of gloves and appropriate protection against cold and heat, and back injury devices.

Effective Solutions

Case studies suggest that the most effective solutions are those derived from engineering controls. Attendees at a University of Michigan-Ann Arbor conference, "A National Strategy for Occupational Musculoskeletal Injury Prevention-implementation issues and Research Needs," pointed out the success of engineering controls in reducing injuries, lowering worker compensation expenses, improving morale and boosting productivity. Typically, management and labor worked together to identify problems and develop solutions.

Attention to ergonomics benefits helps a manufacturer reduce the likelihood of being cited or fined by OSHA. According to Ray Donnelly, chairman of the OSHA Meatpacking Task Force, "The general duty clause enjoins the employers provide a safe and healthful workplace that is free of any recognized hazards. If there is a recognized hazard that is life-threatening, and the employer is aware of the hazard but has done nothing or taken only ineffective steps to correct the situation, the employer may be cited. injuries leading to multiple surgeries or wrist, elbow and shoulder damage ate considered major.

In addition to the desire to comply with OSHA regulations, there are numerous other reasons for foundrymen to invest in ergonomics programs, such as:

* reduced number and

severity of injuries and


* fewer worker compensation


* improvement in product


* improved morale and

team spirit;

better attendance


* increased productivity.

Preventing Low Back Pain

Correct posture means that the worker maintains the normal spinal curves and keeps the body in effective alignment. Deviation from the three normal curves leads to overstretching the supportive structures of the back, such as the ligaments, joints and muscles.

Most commonly, musculoskeletal injuries involving the lower back result from excessive and improper manual material handling. This activity often occurs when items are lifted from conveyors or carts, and sometimes involves moving materials around obstructions, instead of simple lifting or carrying.

To analyze proper ways to prevent lifting and handling damage, it is important to consider the lifting base, the arms, the required movement and the characteristics of the lifted object.

For example, the same amount of lifting force may be required for a one pound sand core four feet away from the body as for a four-pound core carried next to the body. For that reason, it is important to always minimize the horizontal distance as much as possible.

Vertical distance is important too, because it is much more difficult to lift a heavy object from the floor than it is from knee height. Heavy materials should be stored at knee height to help prevent back strain. This is an important principle in engineering design, when storage platforms are constructed to avoid the need for workers to bend or stoop.

The bulk of an object adds to lifting strain as well. As pointed out by Gary Herrin, professor of industrial and Operations Engineering at the University of Michigan, "The average industry person ... still doesn't understand the basic difference between lifting 30 pounds of feathers and 30 pounds of lead. The feathers are much harder to lift because they have to be stored in a large, ungainly box. The 30 pounds of lead, on the other hand, forms one concentrated block of material."(1) Bulky objects that cannot be held close to one worker should be lifted by two workers.

To help relieve back fatigue during lifting, the worker should keep in mind the following steps:

* Spread the feet apart to keep a wide

base of support.

* Bend the knees-not the back.

* Arch the lower back inward by pulling

the shoulders back and sticking

out the chest.

* Hold the object close to the body.

if possible, do one movement at a time.

* Tighten stomach muscles to increase

the pressure in the abdomen. This

helps reduce strain and takes away

extra stress on the back.

* The worker can avoid injury during carrying by following these steps:

* Keep the shoulders and hips aligned.

* Hold the load close to the body.

* Keep the elbows resting against the sides.

* Keep the weight of the load evenly balanced.

* Place the load as close as possible to the elbow.

* Rest large loads against the hip for even better support.

* Turn the body-don't just twist at the waist.

* Lifting objects off shelves and racks can result in considerable injury.

* Back pain can be reduced by following these steps for removing items off shelves:

* Use a stepladder if the load is out of comfortable reach. Avoid overreaching.

* Get help if the load is too heavy or bulky.

* Make sure there is a place to set the load safely and easily. if not, a place should be cleared before moving the item.

* Be sure of firm footing and a solid grasp be - fore moving the load.

* Position the load close to the body.

In addition to these on-the-job means of prevention, regular exercise helps reduce or prevent back injuries by increasing muscular strength and endurance. Workers may want to investigate which exercises help improve back strength, and then make them part of a regular program.

Cumulative Trauma Disorders

CTDS are usually the result of performing repetitive tasks at work or at home. Some of the movements that can lead to CTD include vibrating tools; repetitive, twisting hand movements; exerting force in an awkward position; and excessive pressure on parts of the hand and wrists.

Symptoms of CTDS include a tingling or burning sensation, numbness in the hands or wrists, hand pain that makes it difficult to sleep, pain radiating down the arm, difficulty gripping objects, and pain after repetitive activity.

Some of the injuries that are considered to be CTDS include: * Carpal tunnel syndrome, in which repeated use of a tool compresses the median nerve in the wrist. The worker will notice tingling, numbness and pain. it also is associated with pregnancy and diseases like diabetes, and work stresses that worsen the already existing condition. * Trigger finger, in which the sheath covering the tendon in the hand is inflamed or narrowed. Often, the patient notices cracking knuckles, particularly in the thumb. This condition is caused when the pistol grip of a hand tool is so wide the operator cannot grasp the tool firmly. * Tendonitis, in which the tendons of the fingers, hand or arm become inflamed. The injury may occur in the tendon itself or at the junctions with the bone or muscle. A worker with

tendonitis notices pain, swelling, tenderness

and redness of the hand,

wrist, and/or forearm, and sometimes

reduced mobility of the hands and

fingers. Tendonitis is usually caused

by repetitive motions at work or at


Tennis elbow, in which the tendons

outside the elbow become frayed or

are repeatedly subject to stress. Elbow

pain and a weak grip are common

symptoms. Tennis elbow is a

form of tendonitis and is not associated

with playing tennis.

* Tenosynovitis, in which the lubricating

tendon sheaths become inflamed.

Symptoms include pain, swelling,

tenderness and redness of the hand,

wrist and/or forearm.

* White finger (Raynaud's phenomenon),

in which the fingers blanch, and the

worker experiences tingling and/or

numbness of the fingers or fingertips.

White finger is usually caused by extreme

tool vibration. Often, the condition

worsens when the hands are exposed

to cold weather.

Avoiding CTDS

Some of the common ways to avoid motions that create CTDS include:

* Grip objects correctly. Make sure to use

the correct grip for each tool. It should

not be necessary to grip the tool too


* Keep wrists in a neutral position. The wrists should always be comfortably straight in any type of activity, whether at work or at home.

Adjust the workstation to avoid strain. This could include adjusting the body to the height of the coreblower platform or raising the height of the chair in an office environment.

Vary activities. If possible, vary muscular movements once in a while to avoid excessive repetitive motion. Or shake out the hands or rotate the wrists every once in a while.

* Use the right tool for the job. Something as simple as using the wrong drill size could make it necessary to put excessive stress on the wrist.

Use the right gloves for the job. it's important to use gloves in jobs that involve greatly vibrating tools. But the gloves should fit snugly. Gloves that are too large create the need to grip too tightly, while gloves that are too small cramp muscles and strain tendons.

* Keep hands warm. In cold working conditions, workers may grip objects too tightly.

* Adjust the job to the worker. Don't try to adjust the worker to the physical constraints of the job. Overstretching, instead of using a ladder, can create muscle fatigue and damage to tendons. Tools and equipment should be designed to keep the hands and wrists in the same posture as if they were hanging relaxed at the side. Tool vibration can be reduced by installing vibration isolators in tools or handles, or by using tools that have a rubber housing on the handle.

This article is intended to make foundry workers and managers aware of the impact Federal ergonomics guidelines and repetitive motion-related injuries have upon their operations. However, because of space limitations, it can only serve as an overview.

Foundry employees are urged to further investigate ways to reduce LBP and CTDS in their plants, and to conduct training sessions for maintaining safety in the foundry. Further information may be obtained from OSHA at 202/523-6091 or the National Safety Council at 312/ 5274800.


1. G. Labar, Bent Out Of Shape,' Occupational Hazards, p 37 June 1991).

2. P. J. Sheridan, Meatpackers Move To Cut Injury Rates,'Occupational hazards, pp 8l-82 (May 1991).

3. T. Bedal, The Economics of Ergonomics: What Are the Paybacks?" Safety & Health, p 37 (Oct 1990).

4. G. LaBar, op. cit.

Glossary of Ergonomics Terms

Acute-having rapid onset

Anthropometry-study of human body measurements on a comparative basis, including linear dimensions, reach length, weight, volume and range of movement

Biomechanic-study of the human organism, especially the musculoskeletal system, as an engineering structure (subdiscipline of ergonomics) Carpal tunnel syndrome (CTS) - pressure on the median nerve at the point it goes through the carpal tunnel of the wrist

Chronic-long, drawn-out onset

Communication-transmittal of information. In ergonomics, communication includes these links: man-to-man; man-to-machine (controls); machine-to-man (displays); and machine-to-machine

Compatibility-spatial movement, or conceptual relationships of stimuli and responses, individually or in combination, that are consistent with human expectations

Control-device that transmits information to some mechanism, system component or system. The information may be presented on a display, or it may be manifested in the nature of the system response

Cumulative trauma-injuries or deficiencies in performance, resulting from repetitive movements and the imposition of cumulative work stress Display-part of the environment of an operator that provides him with information relevant to the task being performed

Electromyogmphy-recording of the electrical signal (voltage) generated by contracting muscle tissue. May be directly related to the tension within the muscle

Ergonomics-application of the human biological sciences in conjunction with the engineering, physical and social sciences to achieve the optimum adjustment of man and his work; the benefits being measured in terms of human efficiency and well-being

Human factors engineering-similar to ergonomics, but emphasizing the psychological interactions between people and machines

Kinetic element-functional aggregate of all anatomical structures involved in producing a simple movement of a joint about one of its axes M/M System-any combination of one or more human beings, and one or more physical components, interacting to bring about, from given inputs, some desired output

Raynaud's syndrome-condition caused by an abnormal degree of spasm of the blood vessels of the extremities physical, chemical or emotional factor in disease, causation or fatigue

Tendonitis-inflammation of the tendon

Tenosynovitis- inflammation of the tendon and its sheath

Trigger finger-development of a nodule in the flexor tendon of the finger that catches on the tendon sheath

Vibration-an oscillation wherein the quantity is a parameter that defines the motion of a mechanical system

Vibration white finger(VWF)- Raynaud's syndrome, asscociated with the use of severely vibrating tools Work stress -any external force or environmental variable acting on the human body during task performance

Work tolerance-ability to perform in a physical environment at economically acceptable levels while, at the same time, enjoying adequate levels of physiological and emotional well-being
COPYRIGHT 1992 American Foundry Society, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
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Article Details
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Title Annotation:includes glossary of ergonomics terms; workplace ergonomics
Author:Hille, Holger
Publication:Modern Casting
Article Type:Cover Story
Date:Feb 1, 1992
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