Ergonomic Diagnosis of a Tomatoes’ Sauce Production Station of a Buffet’s Kitchen

Castañon, José

Núcleo de Ergonomia e Segurança do Trabalho [Nucleus of Ergonomics and Safety at Work]/Universidade Federal de Juiz de Fora [Federal University of Juiz de Fora]/Faculdade de Engenharia/Universidade Federal de Juiz de Fora/Juiz de Fora – MG – Brasil/+55 32 3229 3405/ nest@ergonomia.ufjf.br

Marcicano, Angélica

Núcleo de Ergonomia e Segurança do Trabalho [Nucleus of Ergonomics and Safety at Work]/Universidade Federal de Juiz de Fora [Federal University of Juiz de Fora] / angelmarsicano@yahoo.com.brSouza, EglaidaNúcleo de Ergonomia e Segurança do Trabalho [Nucleus of Ergonomics and Safety at Work]/Universidade Federal de Juiz de Fora [Federal University of Juiz de Fora]Portela, MileneNúcleo de Ergonomia e Segurança do Trabalho [Nucleus of Ergonomics and Safety at Work]/Universidade Federal de Juiz de Fora [Federal University of Juiz de Fora]/ milene@powerline.com.brSouza, SôniaNúcleo de Ergonomia e Segurança do Trabalho [Nucleus of Ergonomics and Safety at Work]/Universidade Federal de Juiz de Fora [Federal University of Juiz de Fora]/pramalho@powermail.com.br

Abstract

This paper presents the Ergonomic Diagnosis of a tomato sauce production station of a buffet service that cares to parties, events and the sale of frozen foods. The relations between man, task and machine, the analysis of the operator´s behaviour, the physical environment of the task and the profile and voice of the operator were considered.

Keywords

Ergonomics, interior design, cook.

Introduction

The tomatoe sauce production station, the target-system of this ergonomic study, is the only work station that involves only one employee always responsible for this production.

The other employees of the buffet’s kitchen execute many tasks, alternating workstations according to the work demand of each day of production. The lack of a delegation system of permanent functions to the employees guarantees a rotation in the tasks and a greater knowledge of the productive process.

The operator of the target-system analyzed has been performing this task for eleven years, always in a standing position during the productive process, three times per week, for approximately 1h 30min. In the remaining hours, by means of a similar process, this employee produces onion condiment using thesame station, equipments and utensils. Moreover, she manually produces fillings and pastas, in the period of the afternoon or in the other days of the week.

Aiming the confirmation or refutation of the hypotheses raised in the phase of the Ergonomic Appreciation, it was searched, through the methodical inquiry of the information gotten during thevisits, the deepening of the problems pointed from the following analyses:

The macro ergonomic analysis – a study of the work organization;

The operator’s behaviour during task development – a detailed study of the activities carried out in the time spent in work;

The physical environment – physical data of the environment;

Profile and Voice of the Operator - opinions, complaints, evaluations, suggestions and restrictions of the mentioned employee.

The methods used in the intervention process for the development of the Ergonomic Diagnosis had contemplated video recordings, planned observations of the task, detailed survey of activities, flows intensity studies, sequence, frequency and duration of the assumed positions registers, displacements, interview, questionnaires and evaluation scales of satisfaction, discomfort and pain.

Presentation of the Supra - System

Figure 1 - Plant of the whole buffet (including store and kitchen)

The supra-system involved in this research consists of a kitchen of a buffet’s service that also commercializes frozen foods. This kitchen presents eight work stations, which are: tomatoes’ sauce production; pasta production; pasta and other aliments cooking; ovens; preparation of finger food; refrigeration; packing with setting up of dishes and freezing stock.

The kitchen functions from 8am to 6pm, with a break for lunch, which is established according to the production.

Presentation of System-Target

Figure 2 - Picture of the operator in the work station

The selected target-system comprehends the tomato sauce production workstation that supplies the necessities of the kitchen regarding the preparation of pastas and the preparation of finger food, as well as the dishes that will be frozen.

Figure 3 - Plant of the target-system: 1. Boxes of tomatoes; 2. Tank; 3. Bucket; 4. blender ; 5. Basin with sieve; 6. Garbage bag; 7. Stove.

The task is executed by a 43 year old female operator, 1,62m tall, weighing 85 kg. She performs this task three times per week from 8am to 11:45pm and, after a break for lunch, she assumes a variation of tasks in the many work stations - as well as the other employees do until the end of the working day.

Problems to be prioritized

Considering the problems raised in the phase of the Appreciation, the complaints and opinions of the operator and the results gotten through the analysis of the operator’s behaviour registers during the execution of the task, the following problems had been prioritized for a greater analysis:

- the fact of the operator being on a standing position during all the productive process;

- the necessity of lifting and transporting load due the organization of the supra- system;

- the improper internal planning and furniture of the target-system, that implicate in an uncomfortable execution of the task;

- the lack of use of Individual Protection Equipments and the maintenance of the equipments used;

- the absence of a employee responsible exclusively for the constant cleaning of the work station. Through the microergonomic, the macroergonomic, and the Man- Task- Machine-System analysis, the evidences of the graphs generated from the frequency, duration and sequence of assumed positions registers had been considered. These graphs had supported the evaluation of the pains and lesions the operator presents or will present in a short or a long period of time, if the raised problems are not solved or softened with certain urgency.

Frequency in a period of time of 1 hour (%)

Figure 4 Assumed Positions - Head

Neutral14,42

Flexion >45º

19,23

Left inclination

22,12

Right inclination

8,65

Left rotation

1,92

Right rotation

16,35

Flexion up to 45º

17,31

Frequency in a period of time of 1 hour (%)

Figure 5 Assumed Positions - Trunk

Neutral23,9116,62

Extension

Flexion Abduction

13,04

45,6541,55

39,13

Left Superior Limbs

Right19,67

Frequency in a period of time of 1 hour (%

Superior Limbs

Figure 6 Assumed Positions - Superior Limbs Arm/Shoulder

10,09

24,7732,43

34,8645,95

Left Superior Limbs26,6127,03

40,37

70,2

Right Superior Limbs

Figure 7 Assumed Positions - Superior Limbs Forearm/ Elbow

Neutral Support on analyzed

limb

Thigh flexion Knee flexion Abduction

Adduction

1,541,64

18,03

23,08

24,6224,5923,0824,5929,2331,15

Left Inferior Limb

Righ Inferior Limb

Frequency in a period of time of 1 hour (%)

Figure 8 Assumed Positions - Inferior Limbs

Application of the NIOSH Method

This method was applied due to approach of biomechanical, physiological and psycho-physical criteria, regarding the changeable requirements of the task, in order to determine the maximum limit of manual load lifting (LMC) in unfavorable conditions. This method takes into account the horizontal and vertical distance between the load and the body, the rotation of the trunk, the vertical displacement, the frequency and the duration of the lifting and the coupling between the hand and the load. It also assumes that the lifting position can be freely chosen and that the load is raised with the two hands. Moreover, this method considers the recommended maximum weight in ideal conditions of 23 kg.

The used equation is based on the concept that the risk of pains in the lumbarcolumn associated to the LMC increases according to the task demands and, therefore, the lifting index (IL) can be used to identify potentially harmful lifting tasks or to compare the relative severity of the tasks with the intention to evaluate them or to reschedule them.

Lifting of the tomato box starting from the floor (effective lifted weight = 22kg) Ideal recommended weight after the application of the method = 13.93kg

Lifting of the tomato box starting from the tank (effective lifted weight = 22kg) Ideal recommended weight after the application of the method = 15.87kg Lifting of the bucket with tomatoes (effective lifted weight = 11kg)

Ideal recommended weight after the application of the method = 9.35kg Lifting of the basin with tomato sauce (effective lifted weight = 11.5kg) Ideal recommended weight after the application of the method = 8.42kg

In all the cases, the lifting index was presented between 1,0 the 2,0, evidencing the increase of the risk of injury.

Application of the Method of the Guelaud - LEST

This method evaluates the physical load considering the static and dynamic muscular work and the effects on the organism regarding the unfavorable assumed positions. It considers the physical consuming, the energy expense and the mental load combined with risks of nervous fatigue, the psychophysiological aspects, the environment conditions, the description and the duration of the task for the evaluation of the conditions of the work environment.

In this in case that the results had resulted in a quotation 4 according to the table of LEST results, the analyzed task can be classified, then, as MODERATE, what itdoes not hinder its improvement.

Ergonomic diagnosis

The maintenance of the standing position of the operator during all the productive process involves the extension of the lumbar column and tends to increase lordose. In the same way, the high related frequency of the trunk inclinations can compromise the lumbar column due to the support of extra load.

The bad positions of the superior extremities such as prono supineness of the forearm and frequent adduction and flexions of the arms are also factors of risk of injuries. The regularity of head flexion, for example, can compromise the posterior ligaments of the cervical column causing tension due to the stretching of the muscles of the nape.

The inferior limbs of the operator present varicose veins, which can generate sensation of weight or discomfort, that worsens with the necessity to remain standing. It is recommended to make more support options available to alternate the distribution of the corporal weight during the task. Such incorrect positions are due to the inadequate height of the equipments and furniture used by the operator in the activities of the task, to the precarious system of winnowing, to the layout and the

illumination of the work station and to the lack of support in order to rest one of the legs during the performance of the task while standing.

It is recommended to redesign the tank, attempting to its adjusted height and depth, placing its taps in a more comfortable height; to offer a new system of winnowing, considering the restrictions of the operator; to promote the alignment of the furniture and equipments that will be used during the task; to adjust the lighting system destining specific points of light to the work station analyzed.

The lifting of weight performed in an incorrect way by the operator can be the cause of the appearing of its accented lumbar pain. The combination of high loads and the frequency of their liftings and displacements evidenced in the execution of the task increase the magnitude of the injury more than anyone of these activities analyzed separately. These repeated movements can directly damage the tendons due to the frequent elongation and flexion of the muscles.

It is recommended in this case to indicate a higher and more appropriate place for the storage of the tomatoes; to promote the alignment between the tank and blender, searching the exclusion of the bucket during the task and to study a more appropriate way to take the sauce to the pan. Even so, if the weight lifting is presented as essential during the task, it is advised a following position of the operator for the execution of this activity in the correct way, in other words, she must keep her back extended and flex the knees to catch the object, place the object near to the body and then raise it, extending the knees and the hips.

The operator suffers from arterial hypertension and has eventual chronic headaches. However, due to the malleability of the managemental system, these symptoms could not be related directly to a rigid control of production.

When the blender is functioning, the integration with the other employees becomes very difficult, disturbing the operator in her auditory sense and promoting her isolation from other employees.

The lack of appropriate place for meal and rest, as well as a dressing room for shower after the expedient, are factors of general unpleasantness among the employees.

It is recommended to define ways to increase the acoustic isolation of the blender and other equipments of the supra-system or search the market for more modern and efficient similar equipment that emits less noise; to offer seats in the supra-system; to offer alternatives for lunch and rest (meals tickets); to extend the bathroom of employees, adding a dressing room with bath area.

Despite the employees that are not alert to the imminent risks of shocks or falls due to lack of maintenance and constant cleaning of the place, it is advised to promote the maintenance of the installations in general and to make a specific professional available for the constant cleaning of the system.

The low stature (1.62m), the weight (85kg) and the age (43 years) of the operator had been presented as factors that interfere in the execution of the task, considering the way the work station is today.

In this case, it is recommended the reorganization of the layout of the target- system , the organization and the storage of holders and utensils of the kitchen and the improvement of the blender and winnowing systems. Comfortable, pleasant and

free space in the work area must be watched over, considering the extreme anthropometrical standards and the restrictions of the operator.

Conclusion

The Ergonomic Diagnosis is concluded affirming the suggested recommendations so that the observed constraints, the notes in physical, psychic and cognitive terms of the operator and its work station can be implemented in the ergonomic project and in the project validation concurring for the improvement of this Man-Task-Machine-System in study.

Bibliographical References

MORAES, A. MONTALVÃO, C., Ergonomia – Conceitos e Aplicações. 3 ed. Rio de Janeiro, iUsEr, 2003.

GRANDJEAN, Etienne. Manual de ergonomia: adaptando o trabalho ao homem. 4 ed. Porto Alegre: Artes Médicas, 1998.

WISNER, Alain. Por dentro do trabalho: ergonomia: método & técnica. São Paulo: Editora FTD S.A. 1987.

National       Institute       for       Occupational       Safety       and       Health       – www.cdc.gov/niosh/homepage.html

AMADIO, Alberto Carlos (Coord.). Fundamentos Biomecânicos para a Análise do Movimento Humano. São Paulo: Laboratório de Biomecânica. EEFUSP, 1996.

COUTO, H. A. Ergonomia aplicada ao trabalho – manual técnico da maquina humana. Belo Horizonte - MG: Ergo, v. 1, 1995.

DUL, J.; WEERDMEESTER, B. Ergonomia Prática. São Paulo: Edgard Blücher, 1998. GUÉLAUD, F.; BEAUCHESNE, M.N.; GAUTRAT, J. e ROUSTANG, G. Pour une analysedes Conditions du Travail Ouvrier dans l’Enterprise. Recherche du Laboratoired’Economie et de Sociologie du Travail.Paris: Librarie Armand Colin, 1975.

OLIVER, Jean. Cuidados com as Costas: Um Guia para Terapeutas. São Paulo: Manole. 1999.

OWAS - Manual Ovako Working Analyzing System. Helsinki: Finnish Institute of Occupational Health, 1990.