Participatory ergonomics: a case study of implementing an ergonomics program in a specific company Marcelo M. Soares, Ph.D. ERGOLAB – Laboratory of Ergonomics and Usability of Products, Systems and Production Department of Design / Federal University of Pernambuco Cidade Universitária / Recife-PE / 50.670 – 420 - Brazil E-mail:
[email protected] Keywords: Program of Ergonomics; Committee of Ergonomics; Work analysis. This chapter will address questions related to participatory ergonomics and introduce some concepts and methods. A successful case of implementing this method through the adoption of a Program of Ergonomics [PROERGO] in an alcoholic drinks company, in the city of Recife, Brazil, will be presented. In this context, a Program of Ergonomics is to be understood as a plan of action in which a definition will be drawn up for planning in the area of ergonomics for the company. This involves solving ergonomic problems, training multipliers in this field of knowledge and defining the strategic guidelines which contribute to the identification, analysis, prevention and control of the ergonomic risks in the company.
1. INTRODUCTION The objective of this study was to implement an Ergonomics Program [PROERGO] in an alcoholic drinks company in the Northeast region of Brazil. An Ergonomic Program is understood, in this context, as an action plan in which planning in the area of ergonomics will be defined for the company and involve solving ergonomic problems, training multipliers in this area, of knowledge, and defining strategic guidelines which may contribute to identifying, analyzing, preventing and controlling ergonomic risks in the company (Silveira, 2004; Vidal, 2002). Wilson and Haines (2006), have defined Participatory Ergonomics as “the involvement of people in planning and controlling a significant amount of their own work activities, with sufficient knowledge and power to influence both processes and outcomes in order to achieve desirable goals”. Wilson, Haines and Morris (2005) state that the benefits from the use of participatory approaches may include improved industrial relationships, opportunities for personal development amongst those involved and a spread of interest and expertise in ergonomics. According to Spielholz and Carcamo (2006), the benefits of successful ergonomics program may include not only reduced injuries and worker compensation costs, but also reduced absenteeism, as well as increased morale, productivity, and product quality. 1
The company under study is situated in the metropolitan region of Recife, in the state of Pernambuco – Brazil. The company comprises an administrative unit and another productive unit, and is classified as a Drinks Bottling Industry. There are three working shifts, the last of which is for maintaining the production line and loading trucks for clients. All company staff work fixed hours, without stopping. Most of the activities in the plant require direct activity by manual laborers whose level of education is to have completed secondary school. Initially, at the request of the company, problems were identified in 31 work posts in the production sector. Thereafter, three work posts were selected in order to subject them to ergonomic analysis. These were: the posts of the platform, of loading and unloading and of the inspection department. The targets for conducting the study were:
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Application of the knowledge and competences of the specialist in ergonomics in assessing the organization of production, in working conditions and in conceiving solutions which combine human factors and technical aspects.
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Training of the members of the Committee for Ergonomics [ERGOCOM] and other multipliers by means of generic training courses and customized courses within the company’s reality.
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Discussion of the implementation of the Program of Ergonomics with ERGOCOM members based on the definition of strategic guidelines which may contribute to the identification, analysis, prevention and control of ergonomic risks in the company.
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Implementation of ergonomizing actions with a view to analyzing and finding solutions for ergonomic-related problems of the following natures: physical [e.g. postural, dimensional, instrumental, information and perceptual, activity-related problems, etc.], cognitive [mental workload, decision-taking, stress and training, etc.] and organizational [organization of work, monotony, group work, etc.] identified in the first stage of the work – ergonomic appreciation.
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Affording continuous assistance in the course of implementing solutions with a view to ensuring success in the ergonomic actions to be implemented and to generate indicators which can measure the success of ergonomic actions.
Such actions were possible by means of implementing an Ergonomics Program. According to Silveira (2004), a program is a project written in minute detail which leads to good understanding of the fine detail of a plan. Ergonomics programs are not isolated plans. They only make sense when they form part of the company policy for healthy and safety in work environments; that is, they are part of the company’s strategic plan. 2
An ergonomics program is also the best solution for organizing management actions because it captures the complex reality of work environments in small pieces, thus making them comprehensible, subject to planning and manageable. They are technical solutions the implementation of which depends on how people who make up the organization face up to the problem in an organized, agile and practical way. The main advantages to implementing ergonomics programs in a company, according to Silveira (2004), are: 1. More consistent actions, thus increasing the chances of partnerships with and involvement of the beneficiaries, and generating an impact; 2. People mobilized to participate in actions fostered by the company, thus nurturing internal partnerships; 3. Actions leading to improvements in working conditions with better results and fewer costs thus generating confidence, in the organization and among its stake-holders, so generating a feeling of legitimacy and credibility; 4. Progressive fostering of collective reflection on the experience, thus generating the production of knowledge relevant to other programs within the company; 5. Promotion of space for negotiation and expression of the agents, because this is anchored on targets, objectives and assessment criteria, thus generating negotiation of interests.
2. THE ORGANIZATIONAL STRUCTURE OF THE ERGONOMICS COMMITTEE In order to strengthen the acts of mobilization generated by the internal partnerships, what was undertaken, as an initial action, was the formation of an ergonomics committee, the workers being understood as the main personnel responsible for the changes. Thus, even before the official start of the program, meetings were held with the contracting party to define this committee, which was organized in the format of Action Groups. It is worth pointing out that the composition of the committee brought together various sectors and work teams, ranging from the strategic level to the operational one. The idea of forming an Ergonomic Committee [ERGOCOM] by means of action groups is the specific activity of each member within a duly structured plan. Table 1, below, presents what the structure composing ERGOCOM is, with the concept and objective of each group. Figure 1 presents an outline diagram for the modeling (operational structure) of the ergonomic program in the company under study. The participation of ERGOCOM within the ergonomizing intervention process was necessary, right from the recognition of the problem through the validation of the results. 3
Table 1 – ERGOCOM Action Groups Table 1 – ERGOCOM Action Groups Groups AG1 AG 2
AG 3 AG 4 AG 5
Action Interest Group (IG) and Ergonomics Team Group being trained in Ergonomics, concept, methods and techniques, with the responsibility of ergonomic action in the company. Focus Group – target operators target of the research On-going Monitoring Group – technical authorities Support Group – decision-making authority in the organization for changes
Decision-making Group (AG5)
Consultant team from the university
Management
AG 1
AG2 | AG 4
Mobilization
Interlocutors in the company
(AG1)
Ergonomic Demands
AG 3
Focus
On-going Monitoring Group (AG2 and 4)
Figure 1 – Operational structure of an ergonomics program in the company (based on Silveira, 2004).
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In order to create the Ergonomics Committee in the company, the following procedures were followed: [i] identifying and selecting workers, preferably volunteers, from various sectors so as to represent most of the company’s employees; [ii] giving theoretical and practical training on the basic subjects of ergonomics, in order to level up the discourse among the members and foster the integration of the sectors; [iii] establishing the time-table of systematic meetings for negotiation, discussion and presentation of the recommendations put forward; [iv] defining action strategies for carrying out the recommendations and finally,; [v] generating actions for communicating the actions of the program to the rest of the staff . However, it was observed in the case studies illustrated in this paper, that, because of the trade union organization and the very organizational structure of companies, the formation of the committees and the conduct of the activities can occur in different ways. Figure 2, below, presents the four phases, over which the ergonomics program in the company was conducted.
Phase A: Formulating the Proposal for Ergonomizing intervention
Action plan constructed Teams consolidated
Phase B: Training the teams Conducting the intervention
Multipliers trained Results broadened Action Plan adjusted
Phase C: Acting with the ergo-agents
Multipliers quantified Results disseminated Return of the results
Phase D: Assess and send on the program
Management bases implemented Strategic guidelines
Figure 2 – The four phases which comprise the Ergonomics Program in the Company (based on Silveira, 2004). We wish to make explicit that the method used in implementing ergonomic actions was based on an ergonomic analysis of the human-task-machine system which involve surveys and analyses of issues from the physical environment, the work post and the organizational factors (layout of the space, rhythm of
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work, work routine, breaks, organization of production, etc.) which have an influence on the workers’ behavior and on the quality and safety of their work posts. 3. THE FIRST ACTIONS OF THE ERGONOMICS COMMITTEE Having started in 2003, the ergonomics study of the company’s work posts evolved into an Ergonomics Program in 2005. During the initial phase of the program, strategic steps were structured, which permitted them to be carried out in a consistent and organized way. The first of them consisted of forming the Ergonomics Committee, created, in the first instance, to assist in the internal coordination and mobilization of the staff, with regard to ergonomizing intervention. The second objective was to see it that this Ergonomics Committee, once trained, would assume the conduct of the studies under the supervision of a consultant. The Ergonomics Committee, in this company, was formed even before the official start of the program. Some meetings were held with top management, in which the physical and organizational structure of the committee was defined. During this step, one of the members of the committee put forward a proposal for visual identity which, quickly, became the mascot of the ergonomics program. Today, the image is used in ergonomics advertising campaigns in the company. Table 2, below, shows the composition of the Ergonomics Committee in the company.
Table 2 – Action groups of the Ergonomics Group in the company Groups Action
Agents
AG1
ErgoLab Team; HR Coordination Unit; Occupational Health
Interest Group (IG) and external Consultancy
Doctor AG2
Group being trained in Ergonomics, concept. Methods and
OH Doctor, Specialist in Safety; Human Resources Team;
techniques, with the responsibility of ergonomics action in
Coordinators of the Production areas ; Logistics;
the company.
Standardization; Quality; Engineering and Maintenance
AG3
Focus Group – target operators of the research
All the shop-floor workers and office staff
AG4
On-going Monitoring Group – technical authorities
Staff in charge of the production areas and logistics
AG5
Support Group
NE Plant Manager
– power of decision in the organization
for changes
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The members of Action Group 03 took part intensively in the ergonomic demands, but they can only access the documents made available in the virtual folder of the program open to the public, which contains information that has already been validated by the groups, schedules for undertaking recommendations and the copies of the training events held. The activity of Launch of the Program was planned as the committee’s first action: an event which lasted three days with various activities during this period: 1. Opening – Magna Lecture on how the ergonomics program in the company will work, held for an audience of more than 150 company staff in the warehouse of the plant; 2. Systematic activities – Programmed sessions of talks, given by members of the ErgoLab, with the theme “Day-to-Day Ergonomics”. The talk was given to the five groups, at some time during the company’s program, and took in 100% of stake-holders, including third party contract staff. During the talks, the request was made to fill in a questionnaire so as to identify the positive and negative points of each sector. The objective was to capture, spontaneously, all elements of dissatisfaction that stakeholders feel. 4. Activities for which points awarded 1 – Showing of the film “Modern Times”, with Charles Chaplin, in the company refectory, in order to awaken the critical spirit of ergonomics among the staff; 4. Activity for which points awarded 2 – Competition on phrases which would translate the concept of ergonomics for the company, launched on the opening day, with a deadline for entries on the final day of the event. 5. Closing ceremony – Formal award presentation ceremony for the best phrases in the competition and official presentation of the Ergonomics Committee to all employees. Thereafter, as the second phase of the Launch of the Program, training events run by the Ergonomics Committee took place. The objective was to provide more intensive training in ergonomics to the members of the GA2 and GA4 groups. Table 3, below, shows the committee’s schedule of classes. Table 3 – Schedule of the training events of the Company’s Ergonomics Committee. Actions Training Event 1 Training Event 2 Training Event 3 Training Event 4
Content
Length
Techniques
Origins of Ergonomics 8h Methods and Techniques in 8h Ergonomics 1 Ergonomics Program in companies 4h
Presentations and practical activities in class
Profile and user’s voice
10h
Presentations and practical activities in class Definition of the Tools of analysis
10h
Presentations and practical activities in class
12h
Presentations and practical activities in class
Principles of Biomechanics and Anthropometrics Methods and Techniques in Ergonomics 2
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All the classes took place during working hours, over two consecutive weeks in the month of March and another two weeks in May 2005. In parallel with the training events, the ErgoLab team in partnership with the Ergonomics Committee, began the activities of Exploring the Demand. Since the first ergonomics analysis of the company took place in 2003, a re-analysis of the health and safety conditions of the stakeholders was needed, with a view to comparing the past situation to the current one. In order to conduct this re-analysis of the problems, the first Report on Ergonomic Appraisal. Finalized in 2003, was taken as the base, and a check-list based on the Problematization data was drawn up. The result of the check-list applied by the Ergonomics Committee, in the field, defined which were to be the three priority posts for intervention. Using the perspective of lessons learned, initially, the Ergonomics Committee followed the ergonomics team in the analysis of the first work post – the platform. Next, after the first analysis had been concluded, and action proposals and strategies drawn up, the members of the Ergonomics Committee assumed the conduct of the second and third analysis, and were supervised by the ergonomics team so they had adequate technical support. In June 2005, to give continuity to the ergonomics program, after the second report was finalized, a start was made on the implementation phase of the recommendations for the first work post: the platform (responsible for the unloading of crates of drinks received in the delivery truck). To do so, specific groups of (physical and organizational) work, with a mixture of representatives from action groups GA1, GA2 and GA4. The goal of these work groups was to implement the demands of the work post at the platform.
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Physical Group – directed towards the recommendations of a dimensional order and physical changes of the post;
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Cognitive/Organizational Group – directed towards the recommendations on people management and work procedures.
However, during the start of the second step of the program (analyst of the work post of the glass inspector, the visorista – responsible for the quality control of bottles after they have been cleaned), the need was noted to sub-divide these two work groups still further: Work Group for the Platform and Work Group for the Visor. The first is responsible for implementing the recommendations of a physical, cognitive and organizational order, these being directed towards the platform post and the second, responsible for conducting the analysis and diagnostics of the visor post. These groups went on to hold monthly systematic meetings, in accordance with demand, and were called by the official communicator of the program – the company’s safety specialist.
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We shall present, below, by way of example, the results obtained in the ergonomics analysis of the work post at the platform.
4. ERGONOMICS ANALYSIS OF THE WORK POST AT THE PLATFORM In order to undertake the ergonomic analysis, the Methodology of Systemic Approach of the Human-TaskMachine System was used (Moraes & Mont’Alvão, 2003). This consist of three phases:
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Ergonomic appraisal [consists of a survey of the problems and the identification of the ergonomic dysfunctions of the plant as an industrial unit and specifically of the work posts of the production workers. Within the steps which comprise the ergonomic appraisal there are: the problematization of the Human-Task Machine System (HTMS); the systematization of the HTMS; the ergonomic report on the HTMS and further, the suggestion for improvement.
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Ergonomic diagnostics [consists of the macro-ergonomic analysis, behavioral analysis of the task, analysis of the physical ambience of the task, analysis of physiological components and analysis of the profile and voice of the operators];
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Ergonomic pre-project [consists of the configuration, profile and dimensioning of the work post and recommendations for operational and physical environment of the work posts].
4.1 Ergonomic appraisal As was explained above, this project comprised two phases: the first in 2003, involving the Ergonomic Appraisal and the second, in 2005, with the implementation of the Ergonomics Program. The objective of the Ergonomic Appraisal was to analyze the work posts in the company’s production sector based on identifying possible ergonomic problems existing in each work post. Next, a hierarchical ordering of those problems identified as being the most serious was undertaken. Their gravity will define the urgency of solving the problems pointed up. To do so, aspects of a physical, cognitive, social, organizational and environmental order were taken into consideration, besides other aspects relevant to the demand of the tasks to be undertaken in the various work posts. The tool used for analyzing priorities was the technique of Kepner and Tregoe’s Value Analysis, also known as the G.U.T. (Gravity, Urgency and Tendency) technique. We shall present, below, the steps which comprised the Ergonomics Appraisal.
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4.1.1 Study of the workings of the functioning of the company This initial step targeted understanding how the company worked and analyzing the elements involved in the production process. They consisted of the following phases: [i] Identifying the Productive Unit. This set out to present, among other matters, the location of the company, its mission, the type of production, the target public, the area it served, institutional relations with unions and professional associations and the number of staff. [ii] Drawing up the functional organogram. This was conducted using the hierarchical organogram of the various departments of the productive unit with the objective of being able to situate the work posts which are the object of this survey in the production sector of the plant referred to. [iii] Evidencing the productive process. This was analyzed by means of: [iii.1] Drawing up organograms of the lines of the production of drinks, which characterized the system as semi-automated, displaying direct and indirect human interference in the tasks of: handling and moving the loads, quality inspection of the product, monitoring of and supplies for the machines and technical maintenance in the areas of electronics, mechanics and chemistry; [iii.2] Reporting on the raw materials used in the productive process; [iii.3] Reporting on machines, equipment, and processes involved in the production of drinks; [iii.4] Mapcum-flowchart of the production sector, in which the lay-out and flow of raw materials and people in the production process is analyzed; [iii.5] Analyzing data on the Planning, Programing and Control of Production, including the hours of working, number of staff, planning of production, pauses and changes of shift, production targets, graphical signposting of the production sector (luminous sign-posting and safety sign-posting); and, finally, [iii.6] Characterizing the products, rejects and residues. [iv] Description, characterization of manual workforce, and social benefits. Using assistance from the Human Resources sector, the following matters were identified and analyzed: [iv.1] Age and sex of the workers by sector; [iv.2] Level of school education; [iv.3] Selection criteria for admission to the company; [iv.4] Training after admission to the company; [iv.5] Identification of the criteria for dismissal; [iv.6] Other aspects, such as, criteria for granting holidays, transport, social benefits, leisure activities, salary income, etc. [v] Analysis of data on health and safety of the work. Analyses were made of data obtained from the sector called Specialized Service in Safety and Medicine of Work. Data were analyzed relating to the admission examination, periodic examination, return to work, change of function and data referring to dismissal. Also analysed were data referring to eating habits as a heath factor in the company. A request was made to the company’s medical service for documentation on registering and controlling the obesity of 10
employees. The data referring to the register of occupational diseases was requested with the objective of being able to determine and locate the possible sources which generate problems related to ergonomics. Also analyzed were the register of accidents at work, chemical risks, physical risk (noise, vibration, temperature and illumination). [vi] Verbal reports. Meetings were held with representatives of the workers from the production line, with the objective of discussing questions relevant to the ergonomic study on the work posts of the plant’s production line. Representatives of the workers in the Production, Logistics and Administration sectors took part in the meetings. Based on these verbal reports, problems in these three areas of the company were recorded.
4.1.2 Analysis of problems in the human-task-machine system This comprised the selection and classification of different aspects of the problematic situation and used asystematic observations from all the relevant different problematic elements. The objective was to identify what was wrong, was bad, harmful, did not work, was missing or degraded the work situation. The problems were categorized and presented through photographs. Figures 3 to 8, below, show examples of problems found in the platform work post, in the activity of “manipulation”. In this activity, the operator was responsible for organizing and maintaining the work area clean, accounting for the number of cases which come onto the platform, separating the rejects, broken cases and bottles and sending on the cases to the transport conveyor belt. In Figure 3, one observes the assumption of a cyphotic posture to reach the crate on the lowest level of the pallet. Each case of empty bottles, with dry bottles, weighed 8.57 kilos. If this operation is repeated throughout the working day, it could cause injury to the lumbar region of the vertebral spine.
In Figure 4, one observes the flexion of the trunk to perform the activity of unloading the crates from the pallets to the transport conveyor belt. Maintaining this posture, followed by lifting the weight, can cause muscular fatigue of the lumbar region of the vertebral spine, besides losing strength at some times during the working day.
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Postural problems
Figures 3 and 4 – Examples of postural problems of work done at the work post of the platform.
Dimensional problems
Figures 5 and 6 – Examples of dimensional problems of work done at the work post of the platform
In Figure 5, the maintenance of the cyphotic posture is noted to perform the activity of removing bottles which have items in non-conformity with what is prescribed in the process, from the conveyor.
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While in Figure 6, one observes the inadequate height of the benches for receiving the crates of bottles unloaded from the truck. The non-existence of tubes, or some system which would permit sliding the crate across the platform, makes the operation difficult. Actional problem
Figure 7 – Example of actional problem of work done in the work post at the platform Figure 7 shows an example of an actional problem of work done in the work post at the platform. Using this figure, raising the forearm can be observed in order to reach the crate on the pallet, at a height outside the employee’s comfort area. Maintaining this activity can cause muscular fatigue with loss of strength both in the arm and forearms, and also in the upper region of the back. Architectural problem
Figure 8 – Example of architectural problem of work done in the work post of the platform
In Figure 8, it is verified that the work post is situated at an above ground level, thus requiring the employee to use steps for the operation on the platform. 13
Having completed the problematization, the problems were ordered into a hierarchy so as to prioritize the work posts which would be the object of the ergonomic intervention. The platform work post was considered one of the most critical in the company’s production area, and therefore urgent ergonomic intervention in it should take place. For contractual reasons, the steps described below were only implemented in the second phase of the ergonomizing intervention (in 2005).
4.1.3 Analysis of the company’s documentation Considering there had been a gap of almost two years since the first analysis of the company’s documentation, a re-analysis was needed of the health and safety conditions, with a view to comparing the past situation to the current situation. In order to conduct the re-analysis of the problems identified in 2003, the Report of the Ergonomic Appraisal was taken as a base. The situation was discussed with the Ergonomics Committee and it was decided to draw up a check-list based on the data from the Problematization appearing in the report in order to check the current situation. It could be observed that all the problems previously identified continued to exist. Parallel to the analysis of the problems in the work post, the conduct of the systematization of the human-task-machine system was undertaken.
4.1.4 Systematization of the Human-Task-Machine System The conception of the Human-Task-Machine System (HTMS) is one of the basic concepts of Ergonomics, and focuses on the interaction of human beings with utensils, equipment, machines and ambiences. When Human-Task-Machine communication began to make full use of cognition, instead of the perception of physical objects, the old models were revised and brought up-to-date. Starting with the evolution of the models of the Human-Task-Machine System, new paradigms have been introduced, and cognitive issues and issues of convergence in communication and the primacy of human beings have been emphasized. Therefore, this makes explicit the pertinence of modeling human-taskmachine communication, as a way to guarantee the considerations involved in all the variables of the system, thus allowing for all the aspects of the interaction to be considered. The objective of this step of the ergonomic analysis was to present the human-task-machine system based on models which characterize the serial position of the system, its hierarchical ordering, expansion and communicational modeling.
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First of all, the Characterization and serial position of the system was conducted with the objective of having a better understanding of the relations of the target system with the elements which characterize it. Therefore, the following were defined:
•
Its goal/mission [what is the system for?]
•
The limiting requisites/attributes and of the associated attributes [what should the system have and/or what should the system be?] which foster achieving the goal of the system
•
The environment of the system, which is “outside” the target system and that explains boundaries, influences and imposes limits on the target system.
•
The restrictions [fixed co-actions] which are in the environment of the system and place obstacles in the way of implementing the requisites
•
The entries which determine the actions of the system and which will be processed to generate exits
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The unwelcome results which explain faults or diversions of the system: accidents, defective products, rejects, and pollution.
Figure 9 presents the characterization and serial position of the system, in which the target system [the platform work post] receives goods in from a system which is prior to it [a truck or a pallet] and, for its part, produces goods out for a system which is posterior to it [the unpacking machine]. The goods in target the primary goal of the target system: to feed the production line with empty liter bottles and plastic cases in conformity. By analyzing the system, it was identified that the platform work post assumes an important role in the company, as it controls what enters by way of consumable and what goes out by way of rejects. The control performed in this post serves to measure the quantity of break in production, since the quality program has the number of empty bottle breakages as production indicators.
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Restrictions • Requirement of unloading the truck completely, without a break. • Inadequate physical environmental conditions • Insufficient space to carry out task • Non-existence of a support system for unloading truck • Inadequate height of the pallet for unloading • Inadequate height of the truck’s cargo • Insufficient staff to share the task • Inadequate scheduling of unloading which takes no account of the worker’s physical limitations.
Target Feeding the production line with empty bottles and plastic crates in conformity
Feeder System
Ins
• Truck • Pallet
Plastic crates containing empty and dirty bottles
Target System Sistema Alvo Posto da Plataforma Platform post for de descarga de unloading plastic caixas com cratesplásticas with empty litros vazios liter bottles
Outs
Further System
Complete crates containing empty bottles in conformity
• Unpacking machine
Requisites • Adequate space to carry out task and for workers to move in • Adequate height of the rolling conveyor • Support system for unloading truck • Scheduling unloading of the truck • Scheduling dismounting of the pallet • Adequate height of the pallet • Adequate height of the load on the truck • Adequate environmental conditions • Monitoring of the rhythm of the work.
Results to be avoided Lack of bottles in the packing machine Entry of bottles in nonconformity in the production line Broken bottles Broken crates Osteo-muscular illnesses (back pains) Accidents and incidents at work (cuts, ocular lesion, etc.)
Figure 9 – Model of characterization and serial position of the system.
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Thereafter, a model of the Hierarchical Ordering of the system was mounted. The objective of this model was to position the target system in accordance with its continence or inclusion within hierarchically superior systems. There are, therefore, based on the target system, superior hierarchical levels which are the supra system and the supra-supra-system, up to the ecosystem, and inferior hierarchical levels consisting of sub-systems and sub-subsystems and sub-sub-subsystems (Figure 10).
Ecosystem – Drinks industries of the State of Pernambuco, Brazil Supra-supra-system – Drinks Company Supra-system– Drinks production line
Target-system – Platform post for unloading Subsystem 1 – Unloading of truck
Subsystem 2 – De-polarization
Sub-subsystem 1
Sub-subsystem 2
Sub-subsystem 1
Sub-subsystem 1
Bodywork of the truck
Support table
Pallet 1
Pallet 2
Sub-subsystem 3
Sub-subsystem 4
Sub-subsystem 1
Sub-subsystem 1
Electric conveyor belt
Crates
Binding tape
Stileto knife
Sub-subsystem 5
Sub-subsystem 6
Sub-subsystem 1
Sub-subsystem 1
Empty bottles
Barrel of residues
Crates
Fork-lift truck
Sub-subsystem 1
Sub-subsystem 1
Electric conveyor belt
Barrel of residues
Subsystem 3 – Inspection of material Sub-subsystem 1
Sub-subsystem 1
Empty bottles
Crates
Sub-subsistema 1 Trash bag for recycling tape
Figure 10 – Hierarchical ordering of the system
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The next model to be analyzed was that of the expansion of the system. Its objective was to demonstrate that the task of the production manipulator presented other systems parallel to itself and received as input, information coming from the serial system which precedes it and produced output which succeeded it. There was, however, a hierarchical order and a position in series. Figure 11 shows this model.
Serial System 2
Serial System 1 Target System
Fork-lift truck
Entry of truck to warehouse
Subsystem 1
Subsystem 2
Subsystem 3
Unloading truck
De-palletization
Inspection of materials
Parallel 1 Stock of empty cargo
Parallel 2 Truck inspected
Unpacking machine
Parallel 3 Scheduling the logistics sector
Parallel 4 Scheduling the production sector
Figure 11 – Model of expansion of the system The analysis of the model of expansion of the system allowed for the demands of the system, suggesting, from then on, a better programming of the entry of consumables in order to improve the performance of the manipulators who assume the unloading of the truck. Other aspects analyzed were the need to improve the existing roster and the need to protect the Parallel 1 system (Stock of empty load) against bad weather, for during the winter, with the coming of the rains, the bottles which should be empty arrive full and require an additional task from the worker.
The following step, in the systematization, of the Human-Task-Machine System was the design of the functional action-decision flowchart (Figure 12). This flowchart shows the sequences of the functions/operations – in series, simultaneous, alternative – and the decisions implied.
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Figure 12 – Action-decision functional flow chart Truck
Start
Unloading crates with empty bottles
Truck driver
2 workers
2 workers
1 worker
1 worker
Truck pulls up at the side of the platform
Put the support table beside the conveyor
1 positions himself on back-drop of truck 1 stays on platform
Removes the crate from truck and throws it on transport table
Removes crate from support table & throws it on conveyor
or
1 Pallet Fork-lift operator
1 worker
2 workers
2 workers
2 workers
Puts the pallets on the platform
Remove the tape which surrounds the pallet
Position themselves beside the conveyor
Remove the crates from the pallets
Put the crates on the conveyor
2 workers
1 worker 1
The crates move on to the conveyor
Verifies if the crates and the bottles are in conformity
Are they in conformity?
Put the crates on the conveyor
1 worker
1 worker
Removes broken crates from conveyor and bottles not in conformity
Completes the crates with empty bottles in conformity
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4.2 Ergonomics diagnostics This step of the project is called the Diagnostics, implementation, supervision and accompan of Implementing the Ergonomics Program [PROERGO] in the company.
Ergonomic diagnostics allows the problems prioritized to be examined in depth and predictio
tested. They are considered to be the technological ambience, the physical environment and t organizational environment of the task. This phase is the moment of the systematic observations of the activities of the task, of the
behavior, in a real situation of work. Recordings on video, structured interviews and verbaliz
carried out and questionnaires and scales of evaluation are applied. Also recorded are frequen
sequences and/or duration of postures assumed, gathering pieces of information, putting actio practice, communications, and /or dislocations.
The levels, amplitude and depth of the surveys of data and of the analyses depend on the pr
defined, on the available deadlines and on the budgetary resources. This step is brought to a the ergonomic diagnostic which comprises the confirmation or rejection of predictions and hypotheses. This step is concluded with:
• A table of the review of the literature;
• Ergonomic recommendations in terms of environment, arrangement and conformation of w their sub-systems and components, programming the task – enrichment, breaks, etc.
It is appropriate to mention that the study which began in 2003 tackled the step of ergonomic
specifically the problematization, of the 31 work posts of the company’s industrial sector. Th
phase of developing and implementing ergonomizing actions, three of the thirty-one work po analyzed, were indicated. These were: platform, loading and unloading, and the sector of the
inspectors (visoristas). In this article, we deal only with the actions related to the platform wo The first step of the ergonomic diagnostic was the conduct of interviews with the workers to
information on their physical and psychological conditions and their opinions about the equip work environment. The next item presents, in summary form, the results obtained.
4.2.1 Interview with the workers The interviews, applied through questionnaires, were conducted with the objective of obtaining: [i] data on possible physical and psychological constraints that the workers of the industrial sector perhaps may suffer from in their work place; [ii] subjective opinions about the equipment and the work environment; and [iii] suggestions for the improvement of the equipment and of the work environment.
A total of 101 interviews corresponding to the total number of workers from the production sector. Interviews were held at various times of day, thus respecting the times the workers made available.
It was observed that almost the totality of the respondents with activities related to the industrial sector of the plant [86%, f= 87] consists of male staff, while only 13.9% [f= 14] of the production staff are women. The average of these staff is approximately 30 years old. The question was asked if the workers had suffered from any illness in the last 30 days. 27.6% [f = 24] of the respondents said they had had flu, followed by muscular problems [18.4%, f = 16].
Graph 1 shows the ailments suffered by the interviewees in the last 30 days according to the result of the interviews. It is observed that the region of the lower back was the most mentioned by the respondents [62.4%, f = 63], followed by the head and shoulders/ upper back, both with 50.5% [f = 51], as well as thighs/legs mentioned by 47.5% [f = 48]. Graph 1 – Discomforts felt in regions of the body over the last 30 days by the workers of the industrial sector.
Body region
21
Thereafter, the workers were asked to state the regions of their body where they felt the most pain or discomfort in the last twelve months. Graph 2 shows the results obtained. The five regions most mentioned, by order of what they stated, were: lower back, [60.4%, f = 61]; head [53.5%, f = 54]; thighs and legs and shoulders/upper back, both with values of [43.3%, f = 44].
Graph 2 – Discomforts felt in regions of the body in the last 12 months by workers of the industrial sector.
Body region
The interviewees were also asked to order hierarchically the five regions of the body in which, lately, they most felt discomfort during working hours. The result of Graph 3, below, shows in terms of importance, the regions considered of greatest discomfort: lower back (15.76%), head (14.61%) and fists and hands (12.24%). It is important to highlight that the pains which most bothered the users were: in the lower part of the back, in the head, shoulders, thighs and legs. Discomforts and pains in such segments are typical of maintaining prolonged standing postures while moving loads.
22
Graph 3 – Forming a hierarchy of the pains which most discomfort the workers of the industrial sector in the last 12 months.
18 16 14 12 10 8 6 4 2 0
Next, it was sought to obtain the opinion of the workers of the industrial sector with regard to the conditions of the work equipment (chair, rolling belt conveyor and pallets) and to the work environment. The interviewees gave their opinion about several features of the work chair used during their professional activity. Such opinion displayed a general negative assessment, since the assessment of “bad” was much used to assess the six variables in question (height, ease of adjustment, width, and softness of the seat and softness of the chair-back). Of these six, ease of adjustment of the chair was the main problem identified by the interviewees (68.2% of the interviewees assessed it as bad). The assessment made by the interviewees regarding the rolling conveyors was, in general, positive. However, both the space available for movement between the conveyors, and the space available for movement near the conveyors were assessed as “bad” by, respectively, 43.8% and 42.9% of the interviewees. As to the pallets, there was a general positive assessment: both the width and the length of the pallets were judged as good by 53.6% of the interviewees. Two questions referring to the diagnostic of the work environment were presented. The first requested the workers’ opinion regarding eight characteristics of the work environment: (lighting, noise, temperature, vibration, ventilation, smell, circulation space and colors in the environment). The second was based on a 23
hierarchical ordering of the five worst discomforts identified by the workers in the work environment. The temperature and ventilation were considered as being the two main problems identified in the work environment with an assessment of bad: respectively 54.5% and 48.5%. In the second part of the assessment of the company’s work environment, the data were put into a hierarchy ranging from the variables which caused discomforts to the respondents to those which least bothered them. It was observed that the problems regarding temperature (20.7%) and ventilation (17.8%) of the work environment were regarded as being those which most bothered the interviewees. The last part of the interview dealt with aspects referring to the organization of the work. It was sought to identify the interviewees’ type of relationship with the various sectors and staff of the company. Generally speaking, the assessment was considered good between colleagues of the same function. However, about a quarter of the respondents considered as regular or bad the relationship with the administration staff, the coordinators of the area and the human resources staff of the company. The result of the interviews was useful for the Ergonomics Committee to present various ergonomic recommendations to the company. Next, the dimensional aspect of the platform work post was conducted. 4.2.2 Anthropometric analysis of the platform work post The objective of the anthropometric assessment was to record graphically and to analyze the incompatibilities existing between the work posts of least and greatest dimensions and the operators of extreme dimensions [percentiles 2.5% and 97.5%]. Out of this, it was possible to put forward dimensional recommendations which obey the needs of the activities of the task and the physiological restrictions. By using the positioning the anthropometric mannequins, the actional area and the field of vision of the tallest and smallest user was defined, these being established as a function of the activities of the task. First of all, the extreme dimensions of the platform work post were studied. As an example of the various anthropometric records made, we present, by way of example of anthropometric analysis, Figures 13 and 15 with, respectively, the frontal and overhead views of the intersection of the 2.5% percentile man and the 97.5% percentile man standing on the platform in the activity of unloading a truck.
24
Bodywork of truck
Bodywork of truck
Figure 13 – Lateral view of the intersection of the 2.5% percentile man and the 97.5% percentile man standing on the platform in the activity of unloading a truck.
Bodywork of truck Figure 14 – Frontal view of the intersection of the 2.5% percentile man and the 97.5% percentile man standing on the platform in the activity of unloading a truck.
25
Bodywork of truck
Figure 15 – Overhead view of the intersection of the 2.5% percentile man and the 97.5% percentile man standing on the platform in the activity of unloading a truck. Next criticisms and recommendations were made for the interface zone based on designs with the intersection of the 2.5% percentile man and the 97.5% percentile man standing on the platform in the activity of unloading a truck. As an example, we present Figures 16 and 17.
Figure 16 - Frontal view of the intersection of the 2.5% percentile man and the 97.5% percentile man standing on the platform in the activity of depalletization. 26
Bodywork of truck
Figure 17 – Frontal view of the intersection of the 2.5% percentile man and the 97.5% percentile man standing on the platform in the activity of depalletization. The criticisms referring to Figure 16, with a frontal view in the activity of depalletization were: (see the corresponding letters in the Figure): A – The handrail does not begin on the first step which can cause an accident. B – There is a variation in the height and width of the steps which makes this inadequate for the activity of walking. C – Insufficiency of space for circulation and movement during the activity of depalletization which provokes torsions in the trunk to reach cases and put them on the conveyor. D – The access area to the platform is restricted because of the metallic structure of the steps. E – Misalignment of height of the last step of the steps with the platform. As to the criticisms of Figure 17, with a frontal view in the activity of unloading, they were (see the corresponding letters in the Figure): A – The support table neither possesses an inclination, nor the length nor a sliding system in order to ease sliding the plastic cases to the conveyor. B – The height of the plastic case located on the base of the first column is at an inadequate height for moving the load in the truck. 27
C – The height and distance of the plastic case located at the base of the last column is in an inadequate position for moving the load in the truck. D - The height and distance of the plastic case located at the top of the last column is in an inadequate position for moving the load in the truck. E – The height and distance of the plastic case located at the top of the last column is in an inadequate position for moving the load in the truck.
By using the bi-dimensional anthropometric mannequins [smallest man and largest man] and considering the biomechanical angles of comfort, interface parameters were defined for compatibilizing extreme users in the work posts. These recommendations were obtained using solutions of multiple adjustments, the intersection or compromise for the field of vision and actional area. Dimensional and organizational recommendations were presented for the activities of unloading a truck, the platform, the pallets, the access steps and the actional and visual zones. It is worth observing that the visual requirements and the requisites of visibility, as well as the actional requirements and the biomechanical requisites of moving arms and legs, could only be defined by analyzing the task. After the anthropometric analysis, the analysis of the task and the behavior of the manipulators of the Platform were undertaken and are described below. 4.2.3 Analysis of the task and of the behavior of the manipulators of the Platform Comprehending the demands of the task is investigated using four elements: [a] content; [b] its implications in terms of getting information and visual requirements; [c] what they determine in terms of actional responses and [d] the manipulation of commands such as levers, switches, etc. Based on such elements, the constraints on the production operators were presented, systematized into two instruments:
•
The flowchart of the activities of the task, which comprises the hierarchical and sequential presentation of the activities performed in the work post.
•
Definitions of behavior and behavioral records of the activities through the WinOWAS tool.
28
Flowchart of the activities of the task The flowchart of the activities of the task showed the actions of the manipulators in terms of gathering information, actions being put into practice, movement and communication. This acquired behavior comprised the following activities: 1.
Activities of initialization, which include all the activities before the start of the goal of the system [e.g. meeting with the officer-in-charge, cleaning the area etc.]
2.
Ordinary activities, which comprise the activities of the platform, properly speaking.
3.
Activities of finalization, which correspond to the final closedown of the activities [e.g. exercising control of the entry of material by using a form, etc.]
This research instrument allows the task to be detailed and to explain the functions which fall to the manipulators in their work posts. As an example, we present below the Flowchart of the ordinary activity of the task of “Unloading material” (Figures 18a and 18b). Some lessons were learned based on the analysis of the flowchart of the activities of the task which involved the form in which programming production and information sheets were passed on to the workers, the definition of tasks and positioning on the conveyor, since this worker will be the person in charge of production control in that truck which will be being unloaded, etc. Based on analyzing the task, some recommendations were presented referring to pauses, rosters, furnishing of seat, discussion of the diagrams of the analysis of the task with the ergonomics committee and the workers in order to establish standard procedures for the tasks involved, etc.
Register of the behavior of the manipulators of the Platform After learning of the activities undertaken by the operators, the means involved and the exchange of information, the behavioral registers of the task were compiled. In this study, the semi-quantitative assessment method used to identify harmful body postures during the working day was chosen: OWAS [Ovako Working Posture Analysing System]. According to Long (1993), OWAS allows postural data to be analyzed in two ways: [i] to examine the combination of postures of the back, arms, legs, and forces and to determine their effect on the muscularskeletal system and [ii] to examine the relative time spent in a specific posture for each part of the body.
29
Figure 18a – Flowchart of the ordinary activity of the task of “Unloading material”. Truck
Worker 1 - Dismounting 4a Positions himself at the side of the line of crates which will be taken from the truck..
5a
6a
Withdraws the crates from the truck and places them on the support table.
Advises the truck driver to take the truck away fro the platform
Withdraws all the crates from the truck?
3a
or 1 Turns on the conveyor belt and the fan
2
Puts the support table near the line crates which will be taken from the truck
or Worker 2 - Support
Observes what the load type is
4a Positions himself at the side of the support table
5a
6a Y
Puts the crates on the conveyor belt
Withdraws all the crates from the truck?
Stores the support table
N 3a
Pallets 3b Gets the stiletto knife
4b Cuts the tapes
5b Throws the pieces of tape into the recycling bag
6b Positions himself at the side of the pallet which he will manipulate
7b Checks if there is space on the conveyor belt
30
Figure 18b – Flowchart of the ordinary activity of the task of “Unloading material” (cont.).
Truck (cont.) 7a Goes down the steps
6a
8a Seeks out the checker to know what the truck’s load is
9a
10a
Returns to the platform
Goes up the steps
11a Records the control on a form
12a
Y
Checks if there is a load on the platform
Is there still some of the load ? N
2
End of shift
Pallets (cont.)
7b
Is there space on the conveyor ?
8b
9b
10b
Takes crates from the pallet
Puts the pallets on the conveyor
Checks if there is still some of the load on the platform
Have all the pallets been emptied?
Y Is any of the load left?
N
2
End of shift
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First of all, the performance of the activity was observed and the length of each cycle timed.
observed that, in the normal situation of unloading a truck and of depalletizing, the cycle last
to 2 seconds for each manipulator. It is worth emphasizing that, based on Silverstein et al. (19
repetitive jobs are those with a time cycle of less than 30 seconds [more than 900 times in a w
or when in more than 50% of the cycle time, the same type of fundamental cycles is performe sequence of steps in the work cycle, which are repeated.
Registering the postures was captured on film that was later analyzed. The software WinOwa
from the Department of Occupational Safety Engineering, Tampere University of Technology used to capture and classify the images.
WinOWAS software generates, using data fed into the system, the percentage of frequency sp
postures referring to the back, arms and legs. The system was fed with the information that th carried loads equal to and above 10 kilos during the period in which they were observed.
After registering the postures, WinOWAS classifies them into four categories referring to the
urgency required to apply corrective measures which may reduce harmful posture. Graph 4, b the results obtained for each one of the categories.
According to the following graph, it is observed that the highest indices in categories 3 and 4
harmful according to OWAS) were the activities of unloading a truck [13%] and depalletizati
this last category, the physical burden of the posture is clearly and extremely harmful. Such a the ones that most present postural demands to the operators.
Based on these data, a postural analysis was made and led to the following recommendations
•
Improvements of the work equipment and study on the disposition of equipment in the
•
Enrichment of the task so as to minimize the effects of the postural rigidity.
•
Providing rosters so as to relieve muscular demands arising from the assumption of ina postures.
The next step of the ergonomic analysis was the study of the physical costs of the platform w
Categorias posturais Postural categories
Percentual
1 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%
2
3
4 4 3
4 3
2
2
2
1
1
1
De-palletization Despaletização
Unloading Descarga de c aminhão
Support
the truck
Apoio
Etapas de t rabalho Work phases
Graph 4 – Frequency of the postural categories of the manipulators of the platform
4.2.4 Assessment of the physical costs of the platform workers The objective of this step of the ergonomic analysis was that of identifying possible pains and discomforts suffered by the manipulators in various regions of the body, and if there was any intensification of this pain during the working day. For this step of the study, a sample of 15 workers [nine from the morning shift and six from the afternoon shift] was used. The sample was selected at random. However, only with the manipulators who were on the daily roster of the platform. The analysis of discomfort, one of the techniques for assessing the physical costs on the work post, was carried out by means of a scale of subjective assessment to identify the human costs of the work (Corlett e Bishop, 1976). In order to apply the map of discomfort presented by Corlett e Bishop [op. cit.], use was made of a direct numerical scale [from 1 to 3] associated with the expressions which could define the level of pain or discomfort felt at the moment of assessment. The expressions presented were: no pain, some pain, moderate pain, great pain/unbearable pain. A figure of the human body was used, divided into various 34
segments, in such a way that the respondent could specify the regions of the body in which there were indices of discomforts borne by the subjects involved in the task. The forms with the map of postural discomfort were applied by the members of the Ergonomics Committee. For each worker, three maps of postural discomfort were applied which corresponded to the three moments of the working day: [i] at the start of the shift, [ii] on leaving for the meal-break and [iii] at the end of the shift. The data obtained at the start of the working day are important for trying to identify if the operators have arrived at work already feeling some pain. Figure 19 presents the map of postural discomfort with the responses given by the participants of the study who refer to the sensation of pain based on the relationship of the sensation of pain (numbers in the column: 1 – some pain ; 2 – moderate pain and 3 – great pain/unbearable pain) and the moments of the working day (start of the expedient, leaving for meal-break and at the end of the expedient). If we compare the regions in which pains are most provoked at the thee moments of applying the postural discomfort map, it can be observed that the lower region of the back, about which there was the highest index of complaints, showed a very significant growth during the working day. 7% of the respondents complained of pains at the start of the activities, one third of the sample [30%] complained of pains in this region before the interval for a meal and almost half [40%] had complaints at the end of the working day. The right and left shoulders were the joint second region with the highest index of complaints, and were distributed as follows: 7% stated they began the working day with pains. This number grew to 40% before the meal-break, and this percentage was maintained until the ends of the working day . It can be concluded that the high incidence of pains in the regions of the upper limbs and the back, especially the lower back is the fruit of a poor dimensioning of the work post. Although they are not the champions of complaints, the indices in the register of the pains in the hands, fists and forearms may be the result of the posture with the arms extended above the line of the shoulder lifting and transferring a load over 10kg. Working with the arms stretched can cause risks of pains in the shoulders, upper scapula and arms (possibly periarthritis of the shoulders).
35
Figure 19 – Map of postural discomfort with information referring to the sensation of pain in the three moments of the working day. LEFT SHOULDER
NECK
NAPE
RIGHT SHOULDER
RIGHT SHOULDER
MID BACK
RIGHT ARM
LEFT ARM
LEFT FOREARM
RIGHT FOREARM
LOWER BACK
RIGHT FIST
HIP AND BUTTOCKS
LEFT FIST
LEFT HAND
RIGHT HAND
LEFT THIGH
RIGHT THIGH
LEFT KNEE
RIGHT KNEE
RIGHT CALF
LEFT CALF
LEFT ANKLE
LEFT FOOT
Start of the expedient
Leaving for mealbreak
RIGHT FOOT
RIGHT ANKLE
End of the expedient
36
To conclude the analysis of postural discomfort, it was recommended that
•
Body segments be maintained in a neutral position, since the muscles and ligaments of this position are more relaxed and subject to less force. Examples of bad posture with segments which are not in neutral position are: arms raised to withdraw cases from the last pile of the pallet, twisted wrists on transferring the cases from the support table to the rolling conveyor; neck and head inclined or turned in the inspection of empty liter bottles; trunk inclined and twisted on transferring the plastic cases from the truck and from the pallets.
•
Avoiding that the trunk be inclined forward, for, thus, it will be more difficult for the muscles and ligaments of the back to maintain the body in balance. This can be verified when the manipulator reaches for the piled up plastic cases in order to place them on the rolling conveyor. Maintaining a posture with the trunk inclined causes neck and back pains, besides which working with the arms held up causes pains in the shoulders.
•
Avoiding the postures with the trunk twisted since these cause pressure on the spine when dismounting the pallet.
•
Alternating postures and movements, for neither a prolonged posture nor repetitive movements should be maintained for long periods of time since they are tiring and can cause damage to the muscles and joints. Preventing the repetitive movements of the arms by alternative tasks.
•
Including breaks to avoid muscular fatigue arising from the effort caused by repetitive work.
The last step of the ergonomic analysis was to record cardiac frequency which is shown below. 4.2.5 Register of the frequency of heart beats In recent years, cardiac frequency has been increasingly used as a measure for assessing workload (Kroemer and Grandjean, 2005). One of the main reasons for the spread of this technique is that it is easy to record and to safeguard data. Within certain limits, cardiac frequency increases linearly with the work performed, taking into consideration that the work is dynamic and not static, and that it is carried out at a constant rhythm. When the work is light, cardiac frequency increases rapidly up to a level compatible with effort and is maintained constant throughout the working day. When the working day ends, the heart beat returns to normal after some minutes. On doing heavier work, however, cardiac frequency keeps on increasing until the worker is interrupted or the operator stops because of exhaustion.
37
The analysis of cardiac frequency is made by comparing the beats at rest [before work] and while the task is being carried out. According to Kroemer and Grandjean [op. cit.], the parameters for characterizing the various types of workload are given by:
•
Frequency of the pulse at rest – average frequency of the pulse before work.
•
Frequency of the pulse during work – average frequency of the pulse during the various activities in the working day.
•
Pulse of work : difference between the frequency of the pulse at rest and the frequency of the pulse during work.
Kroemer and Grandjean (op. cit.) recommend that the limit for continuous human work when the pulse of work is measured be considered as up to the limit of 30 beats per minute. The sample comprised 11 manipulators from the industrial sector distributed in the two work shifts [five for the shift and six for the afternoon shift]. The Polar Beat cardiac frequency monitor was used which consists of three components: [a] a transmission unit which contains electrodes inside it, [b] an elastic band and [c] a receiver unit [clock to measure the register of the heart beat]. The register of the cardiac frequency of each one of the subjects of the sample was performed at the following moments:
•
Before the start of the working day, allowing for a fifteen-minute rest after the moment of arrival at work. The waiting time is justified o that the organism might “slow down” after commuting to the place of work.
•
At 20-minute intervals, wt the activity being performed at that time being recorded [unloading truck, depalletization, inspection of the cases, support in unloading the truck, and so forth]. This piece of data referring to the activity performed was, later, analyzed as a way of our identifying which of the activities generates the greatest physical attrition of the employee.
Graph 5 presents the frequency of the cardiac beats in accordance with the activities performed on the platform. According to the data shown, with regard to averages, the activities which obtained the lowest values are: “rest” (85), “Inspection” (91), “Return from break – Immediate” (95) and “Leaving shift” (95). The activities which obtained the highest average values are: “Leaving for break” (101), “Others” (101), “Support to unloading the truck” (111), “Feeding the transport” (113) and “Unloading the truck” (154).
38
It was observed during the activity of “unloading the truck” that the cardiac beats varied on average 69 points starting from the reference value of the moment of rest (namely, 85). In the other activities, this value kept below the 30 points acceptable for the performance of a healthy activity.
180 160 140 120
100 80 60 40 20 0 Rest
Exit for pause
Return Exit from Unloading Support Feeding Inspection pause – shift truck unloading the immediate truck transport
Others
Graph 5 – Frequency of the cardiac beats as per the activities undertaken on the platform. Using this analysis, the activity on the platform can be considered as heavy work. According to Grandjean (2005), heavy work is any activity that demands great physical effort and is characterized by a high consumption of energy and great demands on the heart and lungs. The consumption of energy and the cardiac effort impose limits on the performance of heavy work, and these two functions are generally used to assess the severity of the physical work. The jobs which involve carrying weight are considered as the heaviest forms of work. By making use of the results achieved with this tool, the alternation of operations was recommended using rosters among the platform workers. Thus, more suitable scheduling of unloading of trucks and of pallets was recommended, that is, creating a schedule which makes it possible to have a regular turn-round of the operations undertaken on the platform, seeking by having regard to the physical expenditure of energy of each of the activities, rest for the muscular group which had been used in the previous one, and thus avoiding the physical exhaustion of the manipulator.
39
Monitoring the rhythm of work was also recommended, for it was observed that the manipulator’s rhythm of work on the platform was very intense. This generated physical overload, due to the high degree of osteo-muscular, as well as psychic effort, due to the stress generated by the pressure of deadlines stipulated in the logistics, thus, making it possible for work accidents to happen, and products to be lost, and, consequently, for there to be a reduction in the rhythm of production, as well as spontaneous pauses – initiatives taken by the workers themselves to interrupt the activity, or disguised pauses – short, easy and routine ones such as tidying up a bench, seeking the officer-in-charge, and so on. 5. IMPLEMENTATION OF THE ERGONOMIC RECOMMENDATIONS IN THE PLATFORM WORK POST The Ergonomics Program a significant number of ergonomic recommendations for the platform work post. Such recommendations were grouped into short-, mid- and long-term solutions. We give below some of the recommendations implemented by the company:
•
A model of rostering duties among workers was instituted with a view to lessening the physiological wear and tear inherent in the task.
•
A new support system was tested (a device which allows the table to reach into the full extension of the truck at suitable dimensions and inclination) to facilitate the unloading of trucks.
•
A useable working area was defined at the rolling conveyor for the unloading of cases which takes into consideration the subsequent processing time of the machine – the unpacking machine. All this aims to minimize bad work postures and to institute micro breaks in activity without having an impact on the productivity of the sector.
•
A project was drawn up for the exchange of some pallets that were unsuitable for some tasks.
•
The platform was re-dimensioned because of the insufficiency of space for dismounting pallets.
4. CONCLUSION For companies, viably, to make financial resources available in order to conduct an ergonomizing intervention is not always a reality. This is all the more so when the situation is one of forming an Ergonomics Committee. This is a slow process and certainly one that lasts longer than an intervention conducted only by ergonomists. The studies presented have served as an example for implementing an Ergonomics Program with the help of an Ergonomics Committee. It is important to make clear that the objective of the methodology applied in the company was not only to intervene as a project on the work posts, by making them more adequate for the activities of the users. The fact that the solutions proposed by an Ergonomics team can provide an 40
improvement in the quality of life of staff, as well as in productivity is unquestionable. Nevertheless, experiences undergone in different companies, and corroborated by the study presented in this article, indicate that conventional interventions, when conducted without the effective participation of the workers, very often fall by the wayside with the passage of time, when the modifications no longer seen as constituting a novelty. The jobs done in the company generated very positive results. We highlight the fact of the company’s administration staff being part of the Ergonomics Committee which lent a certain autonomy to the group when managing resources and people. The systematic meetings with the groups generated demands which were passed on the operational body of the plant in a participative way and, at each conclusion, the information was being sent on to the workers themselves so that they might validate and propose changes. It is also important to draw attention to the readiness of the company to release workers to participate in all the meetings of the Ergonomics Commission. This only occurred due to the commitment of the company’s management to the Ergonomics Program. At some points in time, the company was under audit, which limited or even impeded the work of the ergonomics committee. Nevertheless, it is worth making explicit that, although it may be perfectly possible to adjust the method of ergonomic intervention to the reality of each company, it is important to observe the particularity of each company, taking into consideration its potential and its limitations.
6. REFERENCES Long, A. 1993. Overview of the OVAKO working posture analysing system (OWAS). In: Ergonomics in a changing world: Proceedings of the Annual Conference of the Autralian Ergonomics Society, ed. C. Pollock and L, 3–10. Straker. Camberra: Ergonomics Society of Austrália, Hendrick. H. and Kleiner, B. 2001. Macroergonomics: an introduction to work system design. Santa Monica, CA: Human Factors and Ergonomics Society. Kroemer, K.H.E.; Grandjean, E. 1997. Fitting the task to the human: a textbook of occupational ergonomics. Boca Raton: Taylor & Francis, 1997. Moraes, A. de and Mont’Alvão, C. 2003. Ergonomia: Conceitos e Aplicação. Rio de Janeiro: Ed. 2AB. Silverstein, B. A.; Fine, L. J. and Armstrong, T.J. 1987. Occupational factors and carpal tunnel syndrome. American Journal of Industrial Medicine 11: 343 - 358. Silveira, D. M. 2004. Programa de ergonomia nas organizações: reflexões e estratégias para implementação. Rio de Janeiro: Capes/Faperj.
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Spielholz, B.S.P. and Carcamo, E. 2006. Practical interventions in industry using partipatory approaches. In Interventions, controls, and applications in occupational ergonomics, ed. W.S. Marras and W. Karwowsky, 3 1-27. Boca Raton, FL: CRC Press/Taylor & Francis. Vidal, M.C.R. 2002. Ergonomia na Empresa – útil, prática e aplicada. 2ed. Rio de Janeiro: Ed. Virtual Científica. Wilson, J. R. and Haines, H.M. 2006. Participatory ergonomics, In International Encyclopedia of ergonomics and human factors (vol. 1), W. Karwowsky. Boca Raton, FL: CRC Press/Taylor & Francis. Wilson, J.R.; Haines, H.; Morris, W. 2005. Participatory ergonomics. In Evaluation of human work (3rd. ed), ed. J.R. Wilson, N. Corlett. Boca Raton, FL: CRC Press/Taylor & Francis.
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