Indices Assessment of Ergonomic-Psycho-Sociological Workplace in the Metal Casting Industry of El Hadjar (Algeria)

Introduction

Ergonomics is defined as the study of the design of a workplace, equipment, machine, tool, product, environment, and system which takes into consideration human being's physical, physiological, biomechanical, and psychological capabilities and optimizes the effectiveness and productivity of work systems while assuring the safety, health, and well being of the workers [1]. The disciplines of ergonomics include biometric, environmental, cognitive, preventive, conceptual, corrective and specific ergonomics [2]. The application of ergonomic principles in the workplace can result in the following [3]:

• Increased productivity;
• Improved health and safety of workers;
• Lower workers' compensation claims;
• Compliance with government regulations such as Occupational Safety and Health Administration (OSHA) standards;
• Improved job satisfaction;
• Increased work quality;
• Lower worker turnover;
• Lower lost time at work;
• Improved morale of workers;
• Decreased absenteeism rate The improvement of the conditions of work cannot be limited to environmental aspects and physical attributes but the ergonomics aspects too.An ergonomic analysis shows the critical points of the work, through study of the real activity of workers, identifying risks and their characteristics to detect disequilibrium found between the job and the man, capable of providing an increased workload and cause negative health consequences [4]. These improvements will bring more comfort to the workers, who will be better able to perform their tasks, which is interesting not only for the employee, but for the company, which will have best results as a reflection [5]. Also, working practices and conditions that seem harmless can eventually lead to serious illness.

Operations in the iron and steel industry may expose workers to a wide range of hazards or workplace activities or conditions that could cause incidents, injury, death, ill-health or diseases [6]. Workplace risk assessment, which is a regulatory requirement [7], is in most cases, if not always, conveniently left in the hands of the occupational health services (OHS) the companies may be affiliated to Suleiman and Svendsen, [8]. Stanton and Young [9] quantified over 60 ergonomic procedures and/or assessment methods for the workplace. There are numerous methods, which can be objective, subjective, or mixed, some present slight improvement over the others [10].

El Hadjar complex (Algeria) workers are surrounded by potential risks to their health. The aim of the present work was using the Labour Economics and Sociology Laboratory "LEST" method to determine the ergonomic- psychosocial quality of work in a workstation of casting, since this position is one of the major issues of the steel industry of El-Hadjar for the development of metallurgical products that contain minimum defects and provide more homogeneity possible in terms of chemical composition.

Study Methodology

The LEST method [15] was used to perform an ergonomic psycho-social assessment of the factors negatively affecting the physical environment, the physical workload, the psychosocial aspects and the working hours of laborers employed in this setting.

This method proposes to establish a diagnosis of the conditions of work of a workstation are "good" or "bad", "satisfactory" or "harmful";we establish for each element identified a rating of 0 to 10 such that the higher rating to 2 is unsatisfactory and this is one of the main advantages of this method (Table 2). The whole of these quotations be represented graphically by a histogram allowing to have a quick view of the aspects most favorable or the most unfavorable to a workstation.

Indeed, application of LEST Method will allow to show more clearly the problems which deserve to be deepened, it will generate the interest for news studies. The following figure could summarize the diverse stages of use of this method of analysis.

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Data were collected through personal interviews with workers and for the physical atmosphere of work we have used measuring instruments (sound level meters, decimeters, hydrometers, light meters…,). Sixteen variables were measured with LEST method (with Index tables) and clustered into five relevant areas [15]: a) Physical environment: thermal environment, lighting, noise and vibrations. b) Physical workload: static and dynamic. c) Mental workload: time pressure, complexity–speed, attention, and thoroughness. d) Psychosocial aspects: Initiative, social status, communication, cooperation, and identification with the product. e) Working hours.

The following table summarizes, for each of these quotations, the criteria used, as well as the index calculations.

Ergonomics International Journal

• If the measurement by frequency band
• sound intensity by octave band
• limits of bands of octaves
• level of attention

Impulse Noise of intensity $\geq 85$ dB

$$b_2$$
8 Quotations (1 for each octave band)
2 = rating the higher of these 8

$$b_3$$
If intensity $< 100$ dB
- 1 if number of noise $< 15$ per day
- 2 if number of noise $\geq 15$ per day
If intensity $\geq 100$ dB
- 3 if number of noise $< 15$ per day
- 5 if number of noise $\geq 15$ per day

Lighting c
Illumination level at workstation \ (Lux)
Importance of contrast
Level of perception required

Work with artificial light

Lighting provided by tubes

Glare at the workstation

General lighting level of the workshop

$$c_1$$ from 0 to 10

• $$c_2$$
• 0 if it is not permanent
• 2 if it is permanent

• $$c_3$$
• 0 if tubes 2 X 2 and more than 90 cm
• 2 if tubes 2 by 2, but less than 90 cm
• 2 if tubes located more than 90 cm, but not mounted 2 by 2
• 4 if tubes less than 90 cm and not 2 by 2

• $$c_4$$
• 0 if no
• 5 if yes

$$c_5$$
- 0 if it is $\geq 3\sqrt{E}$
- 2 if it is $< 3\sqrt{E}$
(E = illumination at the station)

• Vibrations d
• Frequency of vibrations
• Amplitude of vibrations
• Duration of exposure

$$d_1$$ from 0 to 10

$$d = d_1$$

II. Physical expenditure

• Static Expenses
• Various postures
• Hourly duration of each Working Energy Expenditure
• Work expenditure in kilocalories / day
• sex

$$e_1$$ from 0 to 10

$$e = e_1$$

$$f_1 < 0$$

$$f_1$$ from 0 to 10

$$f = f_1$$

Work expenditure (static + dynamic) is calculated according to the method described on pages 108 to 117 (Guélaud et al., 1975) III. Mental load 1. Repetitive work Time pressure - Compensation method - Ramp-up time - Chain - non-chain - Delays to catch up - Number of breaks Complexity-speed - Average duration of each operation - Duration of each cycle - Number of choices made per cycle - Duration of each cycle Attention - Level of attention required by the task - Duration of maintenance of attention - Frequency of accident risks - Importance of risks - Frequency of risk of deterioration of equipment - Hardware features - Frequency of the risks of rejection of the product - Value of the product - Opportunity to talk with other workers - How long the worker can take his eyes off his job Thoroughness - Level of perception of details - Dimensions of objects 2. Non-Repetitive Work Time Constraint - Chain - non-chain - Delays to catch up - Number of breaks - Possibility of being absent by equal to the big of the 3 quotes being or not replacing - Number of breaks - Possibility to stop the chain or the machine - Compensation method Attention - Level of attention required by the task - Duration of maintenance of attention - Frequency of accident risks - Importance of these risks - Frequency of risk of deterioration of equipment - Hardware features - Frequency of the risks of rejection of the product - Value of the product - Opportunity to talk with other workers - How long the worker can take his eyes off his job - Number of machines or devices to monitor - Average number of signals per machine / hour - Average duration of interventions per hour - Number of different interventions Thoroughness - Level of perception of details - Dimensions of objects IV. Psychosociological aspects Initiative - Possibility to organize his work or change the order of operations - Possibility to control your work place - Ability to get ahead - Possibility of self-monitoring - Possibility of retouching parts - Possibility to adjust the machine - Possibility to intervene in case of incident equal to the big of the 3 quotes

casting workplace with LEST method) and results are presented in the Table 4.

Discussion and Interpretation of the Results

graphically by a histogram that allows quick view of the most favorable and unfavorable aspects to a workstation (Figure 6).

0 2 4 6 8 10 12 14 16

index Figure 6: Indices of the different variables measured in Casting workplace.

The parameters lighting, vibrations, dynamic load, complexity-speed, thoroughness, social status and cooperation were constant in the workplace studied. Concerning the study of the static load, the communication and the identification, we have found that these parameters are not really satisfactory and relatively inconvenient but there is a possibility for improvements. ”Attention” and “initiative” can present a medium nuisance or risk of fatigue. Analysis of the remaining parameters showed significant index for “thermal environment”, “noise”, “time pressure” and “working hours”. These parameters can present serious risks to the health and must be managed [16].

Employers should select the controls that are the most feasible, effective, and permanent as it is mentioned by the National Institute for Occupational Safety and Health (NIOSH) publications in Figure 7.

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By inspecting this hierarchy, we will begin by the elimination of the hazards sources which is the heat. But this factor is the heart of the process; it can neither be eliminated nor substituted. So, after analyzing casting working conditions, we can proceed to the other stages of the hierarchy and after listing the hazards needing controls in order of priority.

We can make recommendations for parameters which showed significant index:

• Thermal Atmosphere: hazards from molten metal processes include the potential for serious and even fatal burns. Prolonged exposure to heat may also cause heat stress and fatigue and even collapse. Recognition of these hazards must be incorporated in training of workers in foundries [17]. To avoid this risk, we should put at the disposal of workers the useful means of protection (ventilation, mineral water, vaporizers humidification, external blinds, personal protective equipment...).
• Noise: Excessive noise is a common hazard in foundries and causes permanent occupational deafness to those exposed. For health protection, we try to reduce the noise at the source, otherwise put actions on the spread of noise the remoteness; compartmentalization and acoustic treatment of the local. Then, we should be looking for working methods that expose workers to shorter durations to noise.
• Static Load: Static work tires the body, and also the mind. Allowing for relief from muscle cramping and other symptoms by taking periodic breaks to move around and do some simple stretching exercises [18].
• Attention: The work in the Foundry is a painful and hard job that can alter the attention. Index of attention at the level of the post of casting in source is important because of its level, the risk of injury, the risk of deterioration of the product also the concentration at work are all important, what determines an unfavorable state that requires an improvement for the reduce. Improve the plan for the prevention for allows identifying and limiting risks related to the co-activity of the persons present on the site during the realization of the work.
• Initiative: The diagnosis of the initiative is dependent on the ability to control the pace at work and the possibility of adjusting the machine. Reward employees for their contribution to the improvement of productivity.
• Working Time: At the level of the casting, the type of schedule is (3x 8h) with a weekly duration of 48 hours. The work in this workplace is very painful. We must reduce the time of exposure by short frequent breaks during the work.

Finally, to prevent heat illness, OSHA presents precautions that can be taken any time when temperatures are high and the job involves physical work:

• Establish a complete heat illness prevention program.
• Designate a responsible person to monitor conditions and protect workers who are at risk of heat stress.

Conclusion

Occupational health and safety (OHS) management concerns the improvement in health conditions at workplace and reducing a sort of costs emanating from work accidents that could originate from by inadequate working environment, insufficient informing and low consciousness level of employees or lack of attention [19]. By using LEST method, poor working conditions in the process of casting in El Hadjar complex lead to many problems , as well as thermal atmosphere, noise, static load, attention, initiative and long working hours, causing serious risks. Poor working conditions are bad news for both employees and employers, resulting in physical suffering and adverse economic impact. Implementing new psychosocial risk-management programs is difficult [20], therefore authorities, employers, workers [21], and trade unions [22] need to increase their participation. The ambition and commitment to prevent all (serious) accidents implies the need for innovation [23]. Finally, it is in everyone’s best interest to apply ergonomics to the workplace. The suggestions offered here should help employees and employers to reduce risks and accidents in casting workplace.

The proposed method has enabled us to assess the working conditions of the workplace `casting` and we determined the most dangerous risks in this process. But other studies with other methods in the same workplace are obligatory for the improvement of working environment.

Acknowledgement

The authors would like to thank the staff of the complex and, particularly Mohammed ALI RACHED Director of rolling mills in SIDER El Hadjer and all the staff of the casting workplace.