Industrial manufacturing, and operations engineering

Summary

Introduction

In general, the upper limb or distal upper extremity (DUE) includes the muscle forming the rounded contour of the shoulder to the hand which is called deltoid region. Therefore, DUEs are the limbs like armpit, upper and lower arm, elbow, wrist and hand. These are perceived to be more associated with nerve injury. The risk to these DUE disorders can be assessed using some qualitative and quantities methods. Moore and Garg (1995) proposed a method ‘The Strain Index’ to analyze jobs for risk of distal upper extremity disorders and to distinguish between jobs which are associated with distal upper extremity disorders from those which are not. However, Drinkaus et al. (2005) proposed that the Strain Index (SI) may be modified to estimate the risk of distal upper extremity injury. The SI was developed and validated using single task jobs. It was proposed that the SI would be more useful; however, if it could be extended to estimate the risk of a job with more than one task. Two methods were mentioned: the first is maximum task and the second is CARD (Cumulative Assessment of Risk to the Distal Upper Extremity) approach. Stephens et Al. (2009) evaluated the SI for various worksites with job titles including assemblers, painters and office workers (which performed very different tasks between the different worksites even with the same job titles), and some unique job titles to specific worksites such as hook fabricator and deck hand. These authors used different SI computation methods and resulted in significantly different SI scores along with different risk level classifications calculated by the different computation methods. Vishal et al. (1999) developed a cumulative trauma disorders (CTD) risk assessment model for predicting injury incidence rates. The model was found best suited for job tasks with cycle times greater than 4 sec. Moore and Garg (1998) evaluated the effectiveness of a corporate ergonomics programme that used a participatory approach to solving problems related to musculoskeletal hazards. The corporation experienced a significant decrease in the percentage of recordable disorders related to musculoskeletal risk factors, a marked decrease in the lost-time incidence rate, and a marked decrease in total and per capita annual workers' compensation costs. Garg et al. (2007) presented three different studies showing that the SI is capable of identifying jobs with no distal upper extremity morbidity as ‘safe’ and jobs with distal upper morbidity as ‘hazardous’.

Summary

Introduction

The implementation of occupational hygiene and pollution control measures is still ignored in various developing countries like India. The agenda of occupational safety is not being taken as seriously in small scale industries, this may be due to illiteracy and cheap availability of workers from a large population. The preventive measures and equipment are taken as unwanted and sometimes not provided by the organization. Employees of small scale industries (SMEs) are mostly migrants and they agree with working environment and never consult about preventive measures. Hence, workers engaged in these units suffer from various occupational health hazards and risks. This chapter mainly focuses upon the occupational heat stress assessment and its hazardous effects.

Heat Stress and Human Performance

All human beings are largely affected by environmental temperature. The physical and mental performance deteriorates because of complex association of physiological and pathophysiological processes. The lack of fluid in human body occurs due to a long exposure to heat stress that lowers patience, possibly affecting mental and psychomotor functions. The assessment of heat stress and physiological response of worker is very vital to maintain optimal working environment for human health and productivity in developing country like India.

Gomes et al. (2002) compared the occupational exposure to heat and protective measures used by the workers of foundry unit and a bottling plant. The foundry workers were found at higher risk of exposure to heat, noise, IR and UV radiations as compared to the workers engaged in the bottle filling unit.

The level of heat stress and noise exceeds the permissible limit. Simultaneously there were observations of high rate of muscle spasm, hearing loss and visual disability (Gomes et al., 2002). The skin temperature is significantly affected by body activities and clothes; thus an index that recognizes work activity and clothing is more appropriate. There must be provision of sufficient rest breaks after a continuous work time so as to minimize the effect of metabolic heat (Onder et al., 2005). The standards of care and awareness will refuse due to any physical discomfort in any working environment which may increase the risk of health and safety in mining (Onder et al., 2005). The systolic blood pressure (SBP) changes with the induced heat stress (Cui et al., 2004).

Summary

Introduction

This chapter comprises of three parts; first part of the chapter briefly describe the environmental law w.r.t. legal control of hazardous substances and processes, followed by basics of safety management. The second part describes about scenario of occupational health and safety in India and abroad. The third part of the chapter represents the results of exploratory case study to bring out the occupational health and safety practices in SMEs and addresses some important issues such as status of health and safety practices in Casting & Forging SMEs, level of use of PPEs, exertions, fatigue and anxiety due to work exposure, work schedule, overtime, alcohol/tobacco/smoking etc intake, work posture and musculoskeletal disorders, health symptoms like respiratory symptoms, BP, hearing disability, etc. and at the end the conclusions of the case study.

Environmental Law – Legal Control of Hazardous Substances and Processes

There is a huge number of chemicals along with extremely toxic substances increasing at a fast pace and their control and effective management is becoming extremely difficult.

About 5 million chemicals have been synthesized in the past 4-5 decades at the rate of 120,000 every year; about 50–70 thousand chemicals are being used extensively in millions of commercial products. There has been a tremendous increase in the chemical and alkali industry since independence. A total of 515 units spread over 20 states in India have been identified as hazardous installations by a nationwide survey undertaken by ILO.

Today India is the leading producer of pesticides with more production in South Asia. There are some reports available which reveal that many factories near Udaipur are engaged in making acids, secret trade name, and highly toxic chemical for exports. It is a banned item in the western countries because of toxicity and poisonous gases and liquid effluents that emanate from it during its manufacture.

Under the confidentiality clause for protection of trade secrets, the chemical formula has been kept a secret from public and officials and consequently the regulatory agencies have failed to exercise control over them. Therefore in this way some laws are itself hindrances against the legal control of hazardous substances in the country.

The idea of management of hazardous substances is relatively new to the Indian industrial, administrative and legal backgrounds. However, the problem of toxic hazards has already touched dangerous proportions. Therefore, there is a great need of emphasis on these issues.

Summary

Introduction

The reasons behind injuries in a variety of work-related circumstances have been possible to observe since last few decades. For example, consider the case of physically demanding jobs such as casting process in steel industries where a number of tasks involve heavy lifting, carrying, pulling, pushing and moving of equipment in awkward postures that may result into musculoskeletal disorders (MSDs). So, the primary cause of musculoskeletal disorders (MSDs) has been found as manual material-handling tasks.

Likewise in the service industry, IT professionals devote six to eight hours on video display terminals (VDT) and consequently they undergo some MSD complaints. Employees of any organization, who are physically engaged in the task, are unknowingly exposed to the bad work posture. In hospitals the professionals such as dentists, ophthalmologists and nurses are exposed to frequent bending posture while attending patients. Similarly in manufacturing industry also the shop floor workers are working in bad postures, chronic effect of ergonomically bad posture could result in MSD complaints like low back ache, neck pain, wrist stiffness, etc. have been reported by different authors like; Singh et. al (2010). These further could result in low back injuries, cervical problems and carpals tunnel syndromes, etc. Therefore, it becomes very essential that as a preventive measure, the work posture of employees/workers must be investigated using suitable tools. Although, there are a number of ergonomic tools available for the MSD risk assessment out of which RULA (Rapid Upper Limb Assessment) and REBA (Rapid Entire Body Assessment) are the most prevailing for work posture assessment.

The objective of this chapter is to make the reader understand about the procedural steps of using the ergonomic tools to analyze the working postures of an employee or workers. Hence the cases of workers engaged in various processes of small scale casting industry have been taken and discussed. The present chapter is confined to the used two assessments tools, i.e., Rapid Upper Limb Assessment (RULA) and Rapid Entire Body Assessment (REBA) that recommend the various body postural changes to be made while working.

In 1993, McAtamney and Corlett develop an ergonomics tool known as RULA which is used to assess the risk of musculoskeletal disorders caused in sedentary tasks having high demand of upper body.

Summary

Introduction to Noise

Any unnecessary sound which creates disturbance to human is generally treated as noise. Thus any unnecessary sound is known as noise that results in disturbance and lowers quality of life which leads to sleep and mental/auditory fatigue. The annoying effect of noise, whether from a factory, motorway, marriage palace or nightclub, varies from person to person. Secondly, it can divert concentration and audible caution signals or interfere with occupation that may result into accidents. Finally exposure to excessive noise can result in hearing loss, provided the exposure period is of sufficient duration; for example, loud music may lead to hearing disorders.

Sound

The pressure difference in air, water or any other medium that is detected by human ear is known as sound. Physically, sound is a vibration of gas, liquid or solid medium particles.

The nature of sound

Sound is a mixture of many waves or fluctuations (sound waves) impinging on the eardrum. It is generated from any energy source setting up hasty and varying pressure in the nearby air. The rate at which variations occur, is called frequency or pitch, and is expressed in hertz (Hz), i.e., cycles per sec. One hertz means the number of complete air waves passing a fixed point per sec. The normal human ear is sensitive to frequencies between about 20 and 20,000 Hz being particularly sensitive in the range 2,000–6,000 Hz. (with maximum sensitivity at 4000 Hz.) that is less perceptive at elevated and lower frequencies.

Characteristics of sound waves

Sound having one frequency only is called as pure tone, such as sound produced by the tuning fork (see Figure 13.1 A). As components distributed over a wide range of frequencies, most of industrial noise are very complex, called broad band (see Figure 13.1 B). Noise produced by looms, an air jet industrial machinery or printing presses, are few examples.

There is a significant noise due to impact between metal parts in steel industry setup. Due to a wide range of impacts per sec, noise is treated as broad band noise, as in a riveting machine. On the other hand noise having widely spaced impacts termed impulse noise, as drop hammer-operated hand tool (see Figure 13.1 C).

Summary

Introduction

In current scenario every one working in the office is greatly dependent upon computers to perform work. Millions of people work with computers every day. Depending upon the type of job, some people perform dedicated computer work, while others do multiple tasks throughout the day. As people are diverse and ergonomics strives to fit the task to the person doing it, therefore, office ergonomics is concerned with the designing of office work place and is deliberated to help an individual for the assessment of the ergonomic design of computer workstation. Therefore office ergonomics help us to setup the job place as per the need of human comfort and provide basic tools to maintain a healthy workspace in the office. Some of the helpful tips show how to identify and correct ergonomic problems to prevent repetitive strain injury, eye strain, fatigue and discomfort.

Issues in Workstation Design

Whenever a work station or office is designed, most importantly the following issues are considered:

Summary

Introduction

The present chapter considers the aspects of physical stresses due to ambience, the omnipresent sensations to which worker is exposed from diverse sections of machinery or from other systems in his workplace. These ambiance pollutants mainly include vibration, the noise, the temperature, the illumination, etc. But the current chapter is confined to a brief description.

Vibration

Vibration is the most fundamental environmental factor. Therefore, it is essential to understand the definitions and parameters of structure-borne vibration, and it will help us understand the processes of other environmental parameters – particularly noise and, to a lesser extent illumination. A body is said to vibrate when it describes an oscillating motion about a fixed position. As like sound, the number of times a complete motion cycle takes place during the period of one second is referred to as the frequency, which is measured in hertz (Hz). The motion can consist of a single component occurring at a single frequency, as with a tuning fork, or of several components occurring at different frequencies simultaneously, e.g., with piston motion of an internal combustion engine.

Vibration signals in practice usually consist of many frequencies occurring simultaneously, so that it is not possible to see immediately, just by the examination of; the amplitude–time pattern, how many components there are and at what frequencies they occur. These components can be revealed by plotting vibration amplitude against frequency, the process being known, as in case of sound as frequency analysis. The graph showing the vibration level as a function of frequency is known as frequency spectrogram, and the vibration amplitude is the characteristic which describes the severity of vibration.

Frequency ranges of significance

(a) The principal hazards associated with vibration are cold body vibration and condition known as vibration induced white finger (VWF), the physiological aspects of which are discussed in another subsequent section. The human body is most sensitive to vibration in the frequency range 1–80 Hz and is principally subjected to vibration in 3 supporting surfaces, viz., the feet of a person while standing, the buttocks of a seated person, and the supporting areas of a person lying down. In the longitudinal direction, i.e., feet to head, the human body is most sensitive to the vibration in the frequency range 4–8 Hz. In the transverse direction, however, it is the most sensitive to the frequency range 1–2 Hz.

Summary

Introduction

In any organization no work can be accomplished without involving manpower; hence, the efforts and time devoted by the manpower are payable in terms of wages and incentives. Before we discuss the various wages and incentive schemes, let us first define these terms. The term wages refers to the payment or remuneration made by the employer for the efforts put in by the worker, employee or staff. According to the Payment of Wages Act, ‘wages refer to all remunerations capable of being expressed in terms of money, which would, if the terms of the contract of employment, expressed or implied, were fulfilled; be payable to a person employed in respect of his or her employment or of work done in such employment and includes any bonus or other additional remuneration of the nature aforesaid which should be so payable’. Thus it may be observed that the wage is a contractual obligation of the management to be paid to the persons employed by them. Wages are tangible and have to be paid in terms of money. The basic wage of a worker, once fixed by the management, must not be altered and has to be paid irrespective of the quality or quantity of work.

Incentive

Incentive may be defined as an influence which tends to produce an increased effort on the part of the employee above a standard. It provides the stimulus to motivate the worker towards higher productivity. Incentives can be negative or positive. The disciplinary actions taken against non-compliance are termed as negative incentives. Psychologically negative incentives are not conducive to human-relations. Positive incentives refer to both extra financial and non-financial benefits provided by the management. Positive incentives would lead to increased production levels and productivity. Non-financial incentives are generally more welcome by the executives. Financial incentives are more effective with the workers.

Incentive plan

Incentive plan refers to financial incentive based on the wage structure. Incentive plan is a scheme of arrangement, which lays down a systematic procedure of payment to the employee based on the performance of the task set. It is developed in such a manner as to produce benefit to both the employee and the employer. The earnings of the worker bear a direct relationship to the quantity of output by the individual or by the group in which he/she belongs.

This book covers the fundamental concepts of work study and ergonomics in a single volume. It discusses the theories of human physiology and cognitive sciences, and evaluates the application of these theories to design a work environment that optimizes work potential and reduces threats of work-related disorders. It provides strategies to design effective work processes and a congenial work environment in order to enhance human well-being and efficiency. The book also explains the ergonomic tools and techniques including biomechanics, work posture assessment tools, anthropometry and work physiology. Using live examples from the industry, the author discusses the principles of work study including string diagram, method study, work sampling and man-machine system. The book demonstrates why it is important to 'fit the job to the man' rather than continuing with conventional practices that 'fit the man to the job'.

Summary

Introduction

Dust is as an aerosol composed of solid inanimate (non-living) particles, as defined by the ILO. The term aerosol implies that airborne particles are carried in or contained in air which may be inhaled. An aerosol can embrace liquid droplets as well as solid particles.

Some dusts are fibro-genic that causes fibrotic changes to lung tissue or toxic, they eventually poison the body systems. Examples of fibro-genic dust are silica, cement dust and certain metals, whereas toxic dust may include arsenic, mercury, beryllium, phosphorous and lead. Some toxic dust, such as arsenic, has an acute effect. Others, such as mercury, have a chronic effect. A number of dusts, although not harmful to health, can have a nuisance effect, for example, dust from combustion of solid fuels.

Definitions Relevant to Dust and Fumes

Particulate–It is a collection of solid particles, each of which is an aggregation of many molecules.

Mist–It is airborne liquid droplets, e.g., oil mist.

Fumes–These are airborne fine solid particulates formed from the gaseous state usually by vaporization or oxidation of metals, e.g., lead fume.

Vapour–These are airborne liquid droplets given off from the surface of a volatile liquid, e.g., trichloroethylene.

The Behavior of Dusts

All dusts are potential aerosols and the behavior of particles is influenced by

Summary

Introduction

Work study is described as a management tool to achieve higher efficiency concerned chiefly with manual work. In order to survive, the industry must use latest technology and most efficient method improvised with a consistent aim of producing best quality goods at lower prices.

One way to improve is through efficient utilization of plant, equipment and labour. Work study is specifically a study of work, describing partition of work into smaller units followed by rearrangement of these units to provide the same effective use at a minimum cost. Work study gives methodology and calculates time period required for the work involved in the process. Robert Owen, Taylor and Bedaux had their vital contributions to this particular topic. According to International Labour Organization (ILO), work study is defined as follows:

Work study is primarily concerned with finding the best ways of performing job and establishing benchmarks based on such ways. It is the technique of method study and work measurement employed to ensure the best possible use of human and material resources in carrying out a specified activity.

In other words, work study can be defined as “the systematic investigation of the methods, conditions and effectiveness of industrial work and thus to determine the way in which human efforts can be applied most economically”.

Historical Glimpse Related to Work

Industrial revolution started around 1770s, when James Watt gave steam engine and Henry Maudslay devised the screw-cutting lathe. In factories, automated machines started replacing workers to enhance production rapidly and more accurately. The interchangeability enabled the factories mass manufacturing. Better machines, modern parts, special tools, fixtures, etc., and then unique products replace custom-fabricate common products. Henry Ford (1863–1947) started mass production through assembly lines.

The concept of scientific management came in late 1800s; Frederick W. Taylor (1856–1915) was the father of scientific management, whereas Frank (1868–1924) and Lillian Gilbreth (1878–1972), were the father and mother of motion studies. Frank Gilbreth was born in Freeport, Maine on 7 July 1868. After finishing school, Frank Gilbreth began to work for a construction company as an apprentice brick layer. At age 27, Frank Gilbreth became the chief superintendent of the company. By the time of his promotion, Frank Gilbreth developed a number of methods, both technical and procedural, for improving efficiency at the workplace, particularly in his field of construction.

Summary

Introduction

The most common condition associated with exposure to noise is occupational hearing loss. Occupational noise is an integral part of the job especially in iron and steel industries, noise may cause severe hearing loss. The hearing loss occurred due to occupational noise exposure is called as occupational noise induced hearing loss or occupational deafness. Worldwide, about 16 per cent of the hearing disability is caused by occupational noise exposure, according to Nelson et al. (2005). The workers in industries such as mining, construction, printing, crushers, drop forging, iron and steel companies are at high risk of NIHL (Nadi et al., 2008). When an individual is over-exposed to excessive sound levels, sensitive structures of the inner ear can be damaged. This can result in permanent noise-induced hearing loss (NIHL). These structures can be injured by exposure to a brief but intense sound, such as an explosion, or from regular exposure to excessive sound levels over time. Noise may cause hearing loss in three ways.

Summary

Introduction

A significant proportion of the Indian population is still struggling for its basic needs: food, shelter, clothes, security and health services. A nation can only raise the level of satisfaction with respect to these basic needs only if the return from resources is maximized or the productivity is improved. Then, the economy will grow and help provide a better quality of life. Productivity at an enterprise is assessed in terms of output of a production variable per unit of input. Fundamentally, it is used to measure the output of resources such as manpower, machinery, materials and money, in producing goods and services or commodities to produce income or profitability. There are ample examples of Japanese manufacturers increasing their productivity, after the Second World War when they faced the dilemma of vast shortage of material and human resources. The problem of Japanese manufacturers was entirely different from their Western counterparts. Later, in the mid-1940s, it was recognized by the president of Toyota Motor Company that American companies were outperforming them by a factor of ten. Therefore, in order to make a move towards rapid movement, Japanese leaders, such as Toyota, Shingo and Ohno devised a new process-oriented approach that is known as the ‘Toyota Production System or Lean Manufacturing’. The main objective of this approach is to reduce wastes, which in Japanese terms is called ‘Muda’ and maximizing the activities that add value to the good or services in the customer's perspective. The term value can be attributed to anything in a product or service for which the customer is willing and ready to pay. The value addition in goods and services will increase the overall profitability of system, company or whole supply chain. According to the lean philosophy, at an organizational level or throughout the supply chain there are three types of activities:

Industrial manufacturing, and operations engineering

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9 - Risk Assessment for Distal Upper Extremities (DUE) Disorders

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15 - Occupational Heat Stress Exposure

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17 - Occupational Health and Safety

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List of Tables

3 - Method Study (Motion Study)

10 - Work Related MSDs Risk and Work Postures Assessment

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13 - Occupational Noise Exposure

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11 - Office Ergonomics

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12 - Physical Stresses

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Frontmatter

5 - Wages and Incentive Plans

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Dedication

Work Study and Ergonomics

References

16 - Dust Fumes and Respiratory System

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2 - Human Factors in Work Study

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List of Figures

14 - Occupational Noise Induced Hearing Loss (NIHL)

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8 - Biomechanics of Manual Lifting Tasks

1 - Productivity and Work Study

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Work Study and Ergonomics

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