ABSTRACT
This article aimed to select items with which to evaluate the ergonomic and safety conditions in tractors used by smallholders and family farmers, based on standardization research and legislation for the sector. Brazil has a comprehensive set of technical standards and legislation for the agricultural machinery sector intended to guarantee product standardization and to promote the health and safety of the users. Therefore, the initial step of this research was to review the technical norms and legislation for the product in order to develop instruments to assess their ergonomic and safety conditions. Twenty-eight Brazilian Technical Standards (NBR) and four Regulatory Norms (NRs) were investigated, in addition to CONTRAN (the Brazilian Traffic Council) Resolution No. 227/2007, which establishes requirements for vehicle lighting and signaling systems, generating 57 safety evaluation items and 35 ergonomic items. These evaluating items were applied to six tractor models commonly sold to smallholders with a rated engine power of 37–57kW. The results indicate levels of safety unconformities as high as 39.7% for the worst case and 44.7% ergonomic-related problems for the same tractor model. These data point to the need for improvements, especially in lower power tractors.
KEYWORDS
operator's seat; noise level; tractor operator
INTRODUCTION
Mechanization in smallholder farms is fundamental for providing profitable production alternatives for farmers by improving practices of soil and water management along with product processing, in addition to reducing the hardship of the tasks performed. One of the machines that has contributed to increasing productivity and efficiency of smallholder's farms is the tractor. It is widely used in agriculture and they have been acquired by smallholder farmers through funding sources such as the National Program for Strengthening Family Agriculture (PRONAF). The purchase of agricultural tractors with funds from PRONAF has proceeded with little or no technical background. It should be noted that the farmer's possibility of payment of the financing installments is the main, if not the only, criterion used. However, other factors are important. Reis et al. (2014)Reis AV, Machado ALT, Gomes MC, Andersson NLM, Machado RLT (2014) A multicriteria model to assess tractors used in family agriculture. Engenharia Agrícola 34(4):727-737. used the multicriteria methodology to identify and evaluate a basis for purchasing decisions using PRONAF resources about low-power tractors that could be used by smallholders in the region of Pelotas, RS. The results were gathered into six main categories: operational cost (weight 0.20), acquisition cost (weight 0.22), ease of maintenance (weight 0.10), tractor capacity (weight 0.26), ergonomics (weight 0.14), and safety (weight 0.08).
Mechanization entails gains in productivity and efficiency, which are easy to measure. On the other hand, we must understand that there are aspects related to farmers' quality of life in regards to occupational health. That was showcased by a survey carried out in the state of Paraná's countryside on accidents related to agricultural activities. They identified 115 accidents, among which 45% were associated with the use of agricultural machinery. The main causes of the accidents identified in this study were distraction, overconfidence, and the absence of personal and collective protective equipment (Ambrosi & Maggi, 2013Ambrosi JN, Maggi MF (2013) Acidentes de trabalho relacionados às atividades agrícolas. Acta Iguazu 2(1):1-13.). Another similar work, executed by Flores et al. (2015)Flores FJS, Rinaldi PCN, Alvarenga CB, Fernandes HC, Cidrini IA (2015) Acidentes com tratores agrícolas em Rio Pomba, zona da mata de Minas Gerais. Revista Árvore 27(6):887-895. in the Juiz de Fora city region in the state of Minas Gerais among agricultural machine operators, found that the most common types of accidents were lateral or longitudinal overturning of the tractor, found in 66% of the accidents. According to the authors, the operators themselves believe that these accidents occur because of their lack of attention and not because of the absence of training of tractor drivers.
Tractor safety parameter analysis was attempted by Oldoni et al. (2017)Oldoni A Spagnolo RT, Morais CS, Rocha MAN, Machado ALT, Reis AV (2017) Safety index for agricultural tractors. Acta Scientiarum Technology 39(1):9-15. DOI: 10.4025/actascitechnol.v39i1.27359
https://doi.org/10.4025/actascitechnol.v...
. These researchers created a checklist comprising 45 of what they called “Components and Security Systems” that were ranked to obtain a “safety index”, classifying the included tractors by their safety levels, thus enabling the tractor buyer to choose a model that offers a lower risk of accidents.
One of the most important systems to increase product reliability and to promote consumer protection is compliance assessment. In Brazil, the traditional mechanisms of compliance assessment are practiced through a specially developed methodology that takes into account tools of risk analysis that are based on legal, environmental, social, technical, and economic-financial aspects. This approach allows for selection of the best suited product-specific compliance assessment mechanisms available in the Brazilian Compliance Assessment System. These are: Certification, Supplier Declaration, Labeling, Inspection, and Testing (Inmetro 2017Inmetro. Avaliação da conformidade. 6 ed. Available: http://www.inmetro.gov.br/inovacao/publicacoes/acpq.pdf. Accessed: May 16, 2017.
http://www.inmetro.gov.br/inovacao/publi...
).
This article aimed to present tools developed for conducting assessments on tractors used on smallholder family farms in regards to recommendations of ergonomics and safety present in the normalization and in the current legislation. In addition, we discuss the aspects related to the results obtained by the application of these instruments on five models of tractors that can be financed with PRONAF funds.
SUBJECT DESCRIPTION
Methodology
It was necessary to first select the machine types to be analyzed according to the models available for governmental financing and by geographical region. Selected agricultural tractors for the study were acquired by PRONAF between the years 2011 and 2013 with a nominal engine power of 37–57kW. Based on this, we chose the following tractor models: Massey Ferguson 4275 (56kW) and 255 (37kW), Valtra A750 (57kW), John Deere 5075E (55kW), and New Holland TL 75E (57kW).
We then proceeded to the documentary study of the printed technical standards available at the Innovation Center for Agricultural Machinery and Equipment (NIMEq) of the Federal University of Pelotas (UFPel) and the Institution's website with free access to the online consultation database of ABNT. We researched 28 Brazilian Technical Standards (NBR) and four Regulatory Standards (NRs) in addition to CONTRAN (the Brazilian Traffic Council) Resolution No. 227/2007, which establishes requirements for vehicle lighting and signaling systems. These standards and resolutions will be presented in the results of this proposal. The legislation and standards consulted are listed in Table 1.
From these resources we have developed data collection instruments to evaluate tractors commonly used by smallholders. We then validated these instruments, first through a pilot test, which used one of the tractor models available at UFPel in order to evaluate its theoretical construction effectiveness. The pilot test allowed for instrument adjustments, legitimizing quantitative data collection performed during the year 2015 at four tractor dealers of Pelotas in the Rio Grande do Sul state. We used new tractor models to avoid including machines that could be worn or adversely affected by misuse.
The materials used in the measurements were: Bosch laser beam, model Professional GLM 30, with a measurement error of ± 2mm; a digital camera with 16.1 Mp and a decibel meter with a 4-digit liquid crystal display, resolution: 0.1dB, IEC 61672 type 2, weighing: A.
For noise measurements, we performed three readings with the tractor engine idling, three readings on the engine speed indicated to produce 540 rpm in PTO (unloaded) and three readings accelerating the engine to full throttle speed, also in a no-load condition. The noise was measured in accordance with the procedures laid down in ABNT NBR 9999. This standard establishes that the test site must have a radius of 20m free from interference (buildings, walls, trees, and other vehicles), the wind speed should not exceed 20km h-1, and the temperature should be between 5 and 30°C. It also explains why it is necessary to measure background noise, which should not exceed 10 dB (A). The microphone of the decibel meter has to be located 250 mm ± 20 mm from the lateral-central plane of the seat, where the highest sound pressure level is found. The evaluated tractors were invariably located in the external area of the dealerships due to these requirements.
It was also necessary to make a device for measuring the operator's station (Seat Index Point - SIP), following the guidance of the standard ABNT NBR NM ISO 5353. In order to simulate the sitting operator, the SIP was used to make measurements that corresponded to the intersection of the central vertical plane passing through the center line of the seat in the theoretical axis rotation between the torso and the operator's pelvis. In this way, the described measures were taken using the SIP, a horizontal and vertical reference ruler, and a bubble level. To determine the SIP, the operator's seat must be in the vertical with horizontal adjustments at intermediate positions according to the ISO 5353 standard. Figure 1 shows the measurements for the free interior space of the tractor cab and Figure 2 shows the location of the SIP on the operating station.
Dimensions established by NBR ISO 4252: 2011, where: A - from the center of the SIP to the center of the backrest; B - SIP to steering wheel; C - SIP from the instrument panel; D - from the platform base to the bottom surface of ROPS; E - from the SIP to the left mudguard; F - from the SIP to the right mudguard.
RESULTS
By analyzing the legislation and standards for agricultural tractors, we have identified 57 safety items and 35 ergonomic items. The scale selected for evaluating the tractor for these items was: conforms (complies with standard), non-conforming (does not meet the standard–stating the reason) or does not apply. Tables 2 and 3 present the items used for the safety and ergonomics evaluations, respectively.
The research of Vilagra (2009)Vilagra JM (2009) Adequação ergonômica de trator agrícola de média potência: construção e validação de um instrumento de avaliação a partir do construto de conforto, segurança e eficiência. Tese Doutorado, Florianópolis, Universidade Federal de Santa Catarina, Programa de Graduação em Engenharia de Produção. emphasizes that assessment tools should be developed and applied to various stakeholders such as farm tractor operators, engineers, specialists, and farmers. This author evaluated 14 comfort elements (ergonomics) and 20 safety items, which were used as a reference. Similarly, Debiasi et al. (2004)Debiasi H, Schlosser JF, Willes JA (2004) Acidentes de trabalho envolvendo conjuntos tratorizados em propriedades rurais do Rio Grande do Sul, Brasil. Ciência Rural 34(3):779-784. proposed an important tool for quantitative ergonomic and safety conditions evaluation of agricultural tractors. Presenting the sensitivity to the variations indicated by the tractors to these characteristics, the Partial Coefficient of Ergonomics and Safety in agricultural tractors (COPES) totaled 43 features in the safety area and 13 in ergonomics.
The research presented in this article used the standardization and legislation of the tractor sector as a data development basis for collection of instruments, selecting 55 safety items and 37 ergonomic ones. After data collection using the previously selected instruments on the chosen tractors at dealerships, we obtained the following results that are presented in Figures 3 and 4, ordered by engine rated power. It is important to note that these values do not include measurements made at the operator's workstation. These will be presented later in the text.
The criteria that do not meet either the norms or the safety legislation pertinent in the surveyed tractors are: pedal location; position and type of access ladder; reach from the operator's hand to the control panel; adjustable seats; protective structures against falling objects and access to danger points; exposure to sharp points or crushing sites while the operator is seated; lack of symbology (with higher occurrence for hot surfaces and chemicals); inadequately located exhaust pipe; lack of safety sensors (such as sound signals that could be installed to alert to the risk of overturning); and adequate fuel supply (a location that favors supply). In Figure 3 we can observe that the level of compliance with safety standards and norms increases along with the rated power of the tractors. The tractor model MF 255 (37 kW) had the lowest safety compliance rate according to our tool and the tractors with a higher power that were evaluated (NH TL 75E and Valtra A750) achieved the highest levels of compliance. These findings agreed with the conclusions of Oldoni et al. (2017)Oldoni A Spagnolo RT, Morais CS, Rocha MAN, Machado ALT, Reis AV (2017) Safety index for agricultural tractors. Acta Scientiarum Technology 39(1):9-15. DOI: 10.4025/actascitechnol.v39i1.27359
https://doi.org/10.4025/actascitechnol.v...
that an increase of safety indexes occurs proportionally to engine power increases in tractors sold in Brazil, which is possibly related to the increased machine price.
Among the items that do not meet the legislation or the standards relevant to the ergonomics we have highlighted: consideration of the body dimensions to design the workplace; possibility of bad posture for the operator causing him or her to perform flexion and rotation of the torso and not respecting the natural angles and trajectories of the body movements; control panel display (that is, hampered by the steering wheel); safety control devices to warn workers about the hazards (NR12); and environmental comfort.
Regarding ergonomics, in Table 4 we present the results of measurements made at the operator's workstations of five models of tractors of the main brands marketed in Brazil. This evaluation was performed in accordance with NBR ISO 4252:2011 Agricultural Tractors - Operator's Workplace, Access and Exit -Dimensions, which specifies agricultural tractor cabs free internal space dimensions for agricultural tractors having a minimum track width exceeding 1,150 mm.
We found that the tractor models surveyed do not fully meet the standardized dimensions. Those models that meet the dimensions, only meet them for D (distance from the platform base to the lower ROPS surface), E (distance from the SIP to the left mudguard), and F (distance from the SIP to the right mudguard). It is worth highlighting the fact that the New Holland TL 75E brand model meets all dimensions of the operator's workplace as determined by the standards.
It should also be noted that some measures were not executable, since the standard NBR ISO 4252: 2011 is applied only to cabined tractors; however, those acquired through PRONAF in the years surveyed had no cabin. Concerning this aspect, a similar research study carried out by Peripolli et al. (2017)Peripolli JLZ, Alonço AS, Possebom G (2017) Conformidade do espaço interno livre de tratores agrícolas e itens de segurança obrigatórios segundo as normas NBR/ISO 4252 E NR 12. Tecno-Lógica 21(2):103-107. using the same standard in tractors with an engine power of 56 to 123kW indicated the internal free space of the cabins were in accordance with this standard. On the other hand, the research by Mattar et al. (2010)Mattar DMP, Dallmeyer AU, Schlosser JF, Dornelles ME (2010) Conformidade de acessos e de saídas de postos de operação em tratores agrícolas segundo Norma NBR/ISO 4252. Engenharia Agrícola 30(1):74-81., performed on national tractors with a rated power between 36 and 132kW, found that these did not meet the minimum requirements of the same standard involving the access and exit of workplaces. The authors also observed a trend towards the conformity of the workplace to standards of accesses and exits with an increase in the analyzed tractor's engine rated power.
Before presenting the results on noise, it is important to note that NR 15 establishes a maximum sound pressure of 85 dB (A) up to a working day of 8 h or 90 dB (A) for a period of 4 h. Additionally, exposure to noise levels above 115 dB (A) is not permitted for individuals who are not adequately protected. NR 17 indicates that noise levels must comply with NBR 10152, observing an acceptable noise level for comfort up to 65 dB (A) and a noise evaluation curve of a value not exceeding 60 dB (A). The NR15 standard was selected as a reference in this work since it supports the Brazilian legislation to provide guidelines on mandatory procedures related to safety and occupational health. Table 5 summarizes the results found during noise measurements of the tractors evaluated in this study.
From the tests, we noticed that at idle speed the noise ranged up to 80 dB (A). For this speed, the lowest measured value was for the Valtra A750 with 58 dB (A), and the highest value reached almost 80 dB (A) in the John Deere brand model JD5075E. At an engine speed to provide 540 rpm at the PTO shaft (unloaded), the Massey Ferguson MF 4275 tractor had the lowest value at 80 dB (A) and the Massey Ferguson MF 255 tractor along with JD5075E had the highest value exceeding 89 dB (A). In the measurement performed when accelerating the tractor until it reached maximum unloaded rotation, the Valtra tractor model A750 again presented the lowest value with less than 86 dB (A), and the tractor Massey Ferguson model MF 255 had the highest value of 95 dB (A). For the noise tests we noticed a high coefficient of variation (CV) for the data from the Massey Ferguson models MF 4275 and MF 255 in idle conditions and for the tractor Valtra model A750 in the measurement with the engine at full speed. The other tests had a CV lower than 8.6% for the two highest rotations.
The results show that the noise levels do not always meet the NR 15 values, mainly for the maximum rotation measured. It should be noted that in smallholder's agriculture there is no formal working relationship, so it is necessary to make farmers aware of the need for safety equipment since it is often not used.
It is important to emphasize that noise testing for new tractors such as those tested at dealerships is not simple to perform, and the standard testing procedures apply only for controlled environments, which could bias the results. This could happen because when the tractor is in the field, performing routine activities, the environmental conditions are not the same as those during testing. Factors such as climate (temperature, humidity, and wind), the soil characteristics, and the tractor operator (habitual driving practices), among others, may alter the noise levels. Baesso et al. (2017)Baesso MM, Modolo AJ, Baesso RCB, Fischer C (2017) Níveis de ruído emitidos por tratores agrícolas. Brazilian Journal of Biosystems Engineering 11(3):229-238. assessed the noise level of 22 different models of tractor sold in Brazil between 1977 and 2013 in the power range of 48 to 158 kW, using the same testing methods presented here. They found that most of the tractors emitted noises higher than the threshold established in NR 15. Also, Nascimento et al. (2013)Nascimento EMS, Viliotti CA, Mion RL, Albiero D, Monteiro, LA (2013) Avaliação do nível de ruído emitido por um microtrator em condição estática e dinâmica. Semina: Ciências Agrárias 34(3):1121-1128. DOI: 10.5433/1679-0359.2013v34n3p1121
https://doi.org/10.5433/1679-0359.2013v3...
reported the results of a work with a walking tractor, disclosing that the tractor presented unsatisfactory high levels of noise and, therefore, suggested that the operators of these machines should use personal protective equipment full time.
FINAL CONSIDERATIONS
Research into Brazilian standards and legislation on agricultural machinery and the like made it possible to develop an assessment tool for brand new tractors concerning their safety and ergonomics issues, comprising 57 safety and 35 ergonomic evaluation items. The application of this tool to evaluate tractors commonly sold to smallholders in the power range of 37 to 57 kW indicates a level of safety unconformities as high as 39.7% for the worst case and 44.7% ergonomic-related problems for the same tractor model. These results highlight the necessity for improvements, especially in lower power tractors. The most frequent problems were the following: internal dimensions and access to the operator's workstation, a seat with limited adjustments, lack of protection against falling objects, unprotected exposure to hot surfaces, and an inadequately located exhaust pipe.
The noise measurement showed that the evaluated tractors generate levels of noise outside the boundaries set by NR15 and therefore require the use of personal protective equipment during their operation.
-
1
This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001.
REFERENCES
- Ambrosi JN, Maggi MF (2013) Acidentes de trabalho relacionados às atividades agrícolas. Acta Iguazu 2(1):1-13.
- Baesso MM, Modolo AJ, Baesso RCB, Fischer C (2017) Níveis de ruído emitidos por tratores agrícolas. Brazilian Journal of Biosystems Engineering 11(3):229-238.
- Debiasi H, Schlosser JF, Willes JA (2004) Acidentes de trabalho envolvendo conjuntos tratorizados em propriedades rurais do Rio Grande do Sul, Brasil. Ciência Rural 34(3):779-784.
- Flores FJS, Rinaldi PCN, Alvarenga CB, Fernandes HC, Cidrini IA (2015) Acidentes com tratores agrícolas em Rio Pomba, zona da mata de Minas Gerais. Revista Árvore 27(6):887-895.
- Inmetro. Avaliação da conformidade. 6 ed. Available: http://www.inmetro.gov.br/inovacao/publicacoes/acpq.pdf Accessed: May 16, 2017.
» http://www.inmetro.gov.br/inovacao/publicacoes/acpq.pdf - Mattar DMP, Dallmeyer AU, Schlosser JF, Dornelles ME (2010) Conformidade de acessos e de saídas de postos de operação em tratores agrícolas segundo Norma NBR/ISO 4252. Engenharia Agrícola 30(1):74-81.
- Nascimento EMS, Viliotti CA, Mion RL, Albiero D, Monteiro, LA (2013) Avaliação do nível de ruído emitido por um microtrator em condição estática e dinâmica. Semina: Ciências Agrárias 34(3):1121-1128. DOI: 10.5433/1679-0359.2013v34n3p1121
» https://doi.org/10.5433/1679-0359.2013v34n3p1121 - Oldoni A Spagnolo RT, Morais CS, Rocha MAN, Machado ALT, Reis AV (2017) Safety index for agricultural tractors. Acta Scientiarum Technology 39(1):9-15. DOI: 10.4025/actascitechnol.v39i1.27359
» https://doi.org/10.4025/actascitechnol.v39i1.27359 - Peripolli JLZ, Alonço AS, Possebom G (2017) Conformidade do espaço interno livre de tratores agrícolas e itens de segurança obrigatórios segundo as normas NBR/ISO 4252 E NR 12. Tecno-Lógica 21(2):103-107.
- Reis AV, Machado ALT, Gomes MC, Andersson NLM, Machado RLT (2014) A multicriteria model to assess tractors used in family agriculture. Engenharia Agrícola 34(4):727-737.
- Vilagra JM (2009) Adequação ergonômica de trator agrícola de média potência: construção e validação de um instrumento de avaliação a partir do construto de conforto, segurança e eficiência. Tese Doutorado, Florianópolis, Universidade Federal de Santa Catarina, Programa de Graduação em Engenharia de Produção.
Publication Dates
-
Publication in this collection
19 June 2019 -
Date of issue
May-Jun 2019
History
-
Received
10 Oct 2018 -
Accepted
18 Mar 2019
