wor-52-wor2042

Work 52 (2015) 185–194 185DOI 10.3233/WOR-152042IOS Press

Case Study

Anthropometric assessment of crane cabinsand recommendations for design: A casestudy

Aleksandar Zunjica,∗, Vesna Spasojevic Brkica, Milivoj Klarinb, Aleksandar Brkica and Dragan KrsticaaFaculty of Mechanical Engineering, University of Belgrade, Belgrade, SerbiabTehnicki fakultet Mihajlo Pupin, University of Novi Sad, Zrenjanin, Serbia

Received 23 May 2014

Accepted 20 October 2014

Abstract.BACKGROUND: Work of crane operators is very difficult and demanding. Therefore, it is very important that the cabin ofa crane be designed on the basis of relevant anthropometric data. However, it is very difficult to find a research that considersanthropometric convenience of crane cabins.OBJECTIVE: From the theoretical viewpoint, it is important to perceive and to classify effects of the anthropometric incompat-ibility of crane cabins. Globally, the objective is to consider the anthropometric convenience of existing crane cabins, and pos-sibilities for improvements of their design from the ergonomic point of view. In this regard, it is significant to detect constraintsthat impede or hinder the work of the crane operators, which could be overcome with certain anthropometric solutions. The mainobjective is to examine whether and to what extent is justifiable to use anthropometric data that are obtained on the basis ofgeneral (national) population, during designing the crane cabins.METHODS: For the assessment of existing crane cabins and the work of operators, four methods were used: observation of thework of the operators and design solutions of the cabins, the checklist approach, interviewing of operators and the experimentalresearch based on obtaining the data on the population of crane operators.RESULTS: Results of the analysis based on the method of observation, analysis based on the application of the checklist, aswell as interviewing of the operators indicate that certain construction constraints of the components in the cabins are the mainreasons of reduced visibility and improper working postures of operators. All this has caused the emergence of continuousmusculoskeletal loading of the crane operators. The results of the anthropometric research that were obtained on the population ofcrane operators in this case study suggest that there is a statistically significant difference, when compared data of this populationof workers with anthropometric data from the general population.CONCLUSIONS: Analyzed workplaces in crane cabins do not correspond to the majority of operators from the anthropometricstandpoint. The conducted anthropometric analysis has been indicated that could be made the mistake, if dimensions of thecabin and layout of equipment would be relied on data derived from the general population of citizens. In order to achievegreater precision in the design and configuration of equipment, it is recommended using the data that are obtained directly on thepopulation of the crane operators when designing the cabin.

Keywords: Operator’s workplace, evaluation, ergonomic design

∗Corresponding author: Aleksandar Zunjic, Department of Indus-trial Engineering, Faculty of Mechanical Engineering, University of

Belgrade, Kraljice Marije 16, 11000 Belgrade, Serbia. Tel.: +381113302311; E-mail: [email protected].

1051-9815/15/$35.00 c© 2015 – IOS Press and the authors. All rights reserved

AUTH

OR

COPY

186 A. Zunjic et al. / Anthropometric assessment of crane cabins and recommendations for design

1. Introduction

Although it is possible to find researches related tothe cabins of cranes, only few studies have taken intoaccount anthropometric and ergonomic factors in eval-uation and designing of crane cabins. In the literature,it can be found a research [1] that is directly relatedto this topic, which was conducted in India. Anotherstudy [2], which is in certain part connected to thistopic was realized in Sweden. However, the work ofcrane operators is very difficult and exacting. Due tothis, it is really significant that the cabin of a crane bedesigned on the basis of relevant anthropometric data.For this reason, the study of this problem from thementioned aspect requires particular attention.

1.1. Effects of anthropometric incompatibilityregarding crane cabins

It is of importance to consider from the theoreticalpoint of view, what are the practical effects that appearas the result of the anthropometric incompatibility, be-tween an operator and a crane cabin. Based on ourpractical study of the work of operators in the cabins ofcranes, taking into account the experiences of other re-searchers, we have noticed the existence of several im-portant effects, which result from anthropometric mal-adjustment of the cabin. These effects can be dividedinto three basic categories. The first category includesthe effects related to the influence that the anthropo-metric incompatibility of the cabin (with equipment init) has on the operator. The second category includesthe effects related to the influence that the anthropo-metric incompatibility of the cabin has on the operat-ing performance and financial losses of the company.The third category includes the effects related to the in-fluence that the anthropometric incompatibility of thecabin has on the safety.

With regard to the first category of effects, it shouldbe noted that from the anthropometric aspect, an inad-equately designed cabin has a large impact on comfortof operators, their health and ability to work. Best prac-tice in connection with the roles and responsibilities ofworkers declares that the operator of lifting arrange-ments must not participate in lifting operations if heor she feels physically or mentally unfit [3]. The prob-lem arises in situations where operators feel unreadyfor work due to the application of improper design so-lutions in the cabin, which are a consequence of in-compatibility between anthropometric characteristicsof operators and designers’ solutions for the equip-

ment. If the equipment does not fit the physical di-mensions of an operator, comfort will be reduced. Asa result, the operator often takes operating positions,which are not suitable for long term operation. For us-age of cranes, prolonged sitting and awkward posturesare risk factors that are customary. If the slope of theupper body is inadequate as a result of discrepanciesbetween the anthropometric dimensions of operatorsand design of individual pieces of equipment (such asa chair, for example), it increases the load on the spine,which can result in shortening the length of the spinalcolumn [4]. Inadequate working positions that are notin accordance with the ergonomic and biomechanicalguidelines and principles can lead to the appearanceof pain in certain parts of the body, as well as to theoccurrence of some occupational diseases during thelonger period of time. In operators of cranes, the painis particularly evident in the lower back. Degenerativechanges in the spine are an additional example of theimpact of the anthropometric mismatch on operator’shealth, which is further manifested through certain im-pairment of their working ability.

Regarding the second category of effects, it shouldbe pointed out that there are several ways in which an-thropometric mismatch of a cabin can lead to the re-duced performance. However, they are all associatedwith the extension of the time required for the execu-tion of working task. If the arrangement of the equip-ment in a cabin from the anthropometric aspect doesnot fit the operator, the worker is forced to spend agreat part of the working time in the uncomfortableworking position, which often limits unconstrainedperforming of working movements. Due to the exis-tence of these limiting conditions, the employee worksmore slowly. Even when movements are not restricted,certain sitting positions can also lead to the decreasedperformance in the task, which is based on the data en-try [5].

In addition, as a consequence of uncomfortableworking position, the operator is forced to make morefrequent breaks. Due to the long-term work in inad-equate working conditions, over the time among theworkers particular health problems appear, which leadaccording to certain dynamics to the absenteeism ofworkers. Besides the allocation of significant financialresources for the treatment of workers due to the oc-currence of occupational diseases, the employer is of-ten not able to find a replacement in time for the sickworker, which may delay the completion of work forsome time. All this influences the working process thattakes place at a slower pace than planned, which resultsin reduction in profit due to reduced performance.

AUTH

OR

COPY

A. Zunjic et al. / Anthropometric assessment of crane cabins and recommendations for design 187

Regarding the third category of effects, it should benoted that the precision of the execution of a task is di-rectly related to the anthropometric compliance of thecabin and equipment in it. Inadequate shape of con-trols, inadequate dimensions of control devices, theirinadequate allocation within the cabin, as well as theinconsistency of forces that are required to activate thecontrols with the anthropometric characteristics of theoperator, can affect the accuracy of the execution ofworking task. The mismatch between design solutionsin the cabin and anthropometric characteristics of op-erators additionally causes the appearance of prema-ture fatigue. However, fatigue of operators is one of themain reasons causing unsafe practices of tower craneoperations [6]. Visibility from the cabin to a great ex-tent also influences on the accuracy of execution of thework. Inadequate construction solution for the cabin,which is not harmonized with the anthropometric char-acteristics of the operator, can lead to a reduced visi-bility, which can affect the accuracy of the executionof working task.

However, imprecise execution of working task mayendanger the safety of cargo, as well as people whoare in the range of crane operations. As a result ofimprecise execution of working task, the cargo maymiss the target, to hit the second object, to release, orfall to other workers or bystanders. Injuries caused bya falling cargo are not a rarity. For example, in theNetherlands, crane activities are responsible for 4% ofthe reported accidents [7]. According to the Pratt etal. [8], between 1980 and 1989, cranes were involvedin the greatest number of fatalities within the con-struction industry in the United States. According tothe statistics from Occupational Safety and Health Ad-ministration, 137 crane-related fatalities were recordedfrom 1992 to 2001 in the U.S. Besides, according toKawata, Japan recorded 41 fatalities resulting fromcrane accidents in 2006 [6]. Operator’s safety may alsobe compromised if the cabin access (stairs and other el-ements) is not designed according to the anthropomet-ric characteristics of the operator. The effects of the an-thropometric inadequacy of the crane cabin are shownin Fig. 1.

2. Goal of the research

All the above effects point out to the importance ofthe anthropometric research, in order to gain insightinto the suitability of existing design solutions of cranecabins. The conclusions derived from such a study may

also be of importance for designing of new cabins orredesigning the existing solutions.

Oborne [9] indicates to the importance of proper se-lection of anthropometric data, which will be used fordesigning. He cites a research that was performed byLodge, who points out that US Navy pilots were signif-icantly taller than the non-Navy personnel whose mea-surement standards had been used for designing of theaircraft cabin that was studied. As a consequence ofthis omission, pilots with heights that were exceeded183 cm were disproportionately more represented inaccidents. Sanders and McCormick [10] consider thatanthropometric dimensions between people working indifferent occupations are possible. However, it is notknown whether the population of operators of cranesdiffers in anthropometric dimensions from the generalpopulation of citizens.

Our research was focused on the cabins of cranes, ar-ranged in a number of locations in Serbia. One sourceof the problem was the fact that operators handlemainly with old equipment, which has not previouslybeen the subject of a complex evaluation in terms ofsuitability. This equipment has not been the subject ofany kind of redesigning. Preliminary information aboutthe personal problems of operators, losses in work effi-ciency and profit, as well as information about the less-ened safety were the basis for engaging in researchingof these problems.

The object of the case study that will be presented inthe continuation was to evaluate from the anthropomet-ric point of view the suitability of existing crane cab-ins. This refers to the assessment of operator’s spacewithin a cabin, positioning the equipment and evalua-tion of designers’ solutions for certain equipment in thecabins from the ergonomic, i.e. anthropometric view-point. The final aim of this study is to come to the rel-evant recommendations that are established on the er-gonomic principles, on the basis of the complex as-sessment of cabins of cranes, which would be benefi-cial for designers of the crane cabins in terms of fur-ther improving the health and comfort of the operators,the safety, and for increasing the performance from thisimportant aspect.

3. Methods

For identifying of problems within the existing de-sign solutions for crane cabins, as well as gathering ofinformation that could be used as reference for the de-sign of the next generation of crane cabins from an-

AUTH

OR

COPY


Fig. 1. Schematic illustration of the effects that arise as a consequence of anthropometric incompatibility of the crane cabin.

thropometric point of view, a complex methodologicalapproach was applied. This approach included the fol-lowing methods: a descriptive analysis based on obser-vation, an analytical method based on the use of thechecklist, interviewing method (as a complement to themethod based on the use of the checklist) and anthro-pometric analysis.

The main goal of descriptive analysis consistedof collecting data, primarily from the anthropometricstandpoint, in order to obtain the global insight intothe state of the system, which consists of the cabins ofcranes from different manufacturers and operators whouse them. For the descriptive analysis, experts with theknowledge in the field of ergonomics, industrial engi-neering and mechanical engineering were responsible.

After the initial description of the system, it was nec-essary to select an appropriate checklist, which will asfar as possible reflect the problems in the consideredarea of design. For filling the checklist the operatorswere responsible, for the purpose of obtaining the in-sight into the main problems they face in their work.The aim of the interviewing method consisted of col-lecting the data related to specific and other problemsthat crane operators have in their work, which couldnot be detected by using the checklist.

The purpose of the anthropometric measurementconsisted in collecting the relevant data, in order ofidentification of values (the measures) that are of inter-est for the assessment of crane cabins from the stand-point of anthropometric suitability, as well as for ob-taining the other related information that can presentthe starting point for their further designing from theanthropometric aspect.

This research included more crane models from dif-ferent manufacturers: Liebherr, Metalna, Min, Litost-roj, Gosa, Clark and Ilr. Age of cranes was in therange from 0.12 to 40 years. Their average age was35.8 years.

Fig. 2. An example of a design solution of a crane cabin, where cer-tain structural elements hinder seeing of operators from the cabin,causing in that way frequent changes of body positions.

4. Results and analysis of results

Below will be successively presented and analyzedresults, based on the application of the four previouslymentioned methods.

4.1. Descriptive analysis

Among cranes that have been with different load ca-pacity, there were differences in design of the cabins.These differences are related to their size, as well as tothe spatial distribution of displays, controls and othercomponents in the cabin. Cranes are located, as alreadymentioned, in several different locations throughoutSerbia. Figure 2 shows an example of the cabin of acrane, which is situated on the leg of the portal besidethe overhang (this crane has the function of cleaningof the bed of the Danube River, and is located on theDjerdap 1 hydroelectric power plant near Kladovo).

AUTH

OR

COPY


All operations with cranes have been performedmanually. Accordingly, in order of precise execution ofworking task, it is important that eye – hand coordina-tion is not affected by hampering factors. However, itwas observed that there are two main factors relatingto the design, which hinder controlling the operations.

The first factor is related to the reduced visibilityfrom the cabins, as a result of poor construction solu-tions, where the floor surfaces were made of opaque,solid material. As a result, an operator often cannot seean object that is transferred, without moving from theneutral, sitting position. This has the consequence thatthe operators are forced to occupy an inclined posi-tion, which may vary from case to case, and even dur-ing the execution of the same work operation. Often,operators due to insufficient sitting height and designconstraints are forced to use standing position, in or-der to track the flow of material, while they work withcontrols at the same time. In addition, individual con-struction solutions of cabins are such that the vision ofoperators is reduced as a consequence of the smallerwindow size, or the existence of certain structural ele-ments (e.g. safety bars, as shown in Fig. 2), which actas a hindering factor in relation to the visual field. As aresult, coordinated handling with the controls becomesless effective, because the operator must periodicallyor continuously to perform assessing his position in re-lation to the controls. At the same time, he has to ad-just force and torque in relation to his current position,while simultaneously, he monitors the position of theobject that is transferred.

Second disturbing factor is related to the positionof the controls in space. Their arrangement is in somecases such that the limbs of operators are in the exten-sion, or near maximal extension. This working positioncertainly is not optimal.

In most locations, the operators work in two or threeshifts. This means that in the same workplace worktwo or more operators. However, in most cases, the el-ements that influence the anthropometric suitability inthe cabin of a crane, such is, for example, the chair,cannot be adjusted. As a result, if the operators are notthe same, or nearly the same constitution, it cannot beexpected that the same workplace be appropriate for allworkers.

The operators primarily work in sitting position.Due to the improper design of working chairs, craneoperators have mainly exposed to the static stress. Inthis sense, the spine is continually statically loaded,especially when the operator is not leaning back inthe chair. This situation often has appeared because of

need of translation of the trunk in relation to the sur-face for sitting (due to necessity for supervising theexecution of working task). Due to the leaning posi-tion that relates to the monitoring of the position of acargo, the neck is the longest part of working time inthe flexed position. Depending on the distance betweenthe starting and ending location in which the cargo istransferred, the burden can pass considerable distancesin some situations. This has as a consequence that theneck of operators is in addition to bending exposed totwisting, when the cargo is moving laterally in relationto the position of the operator. Prolonged operation inthis awkward position can cause pain in the neck inaddition to the reduced blood flow to the head, whichresults in headaches and in some cases even dizziness.

From other parts of the body that are particularlyvulnerable, it should be mentioned the shoulder region.In addition to the aforementioned reasons that con-tribute to the load of this part of the body, the lack ofsupport for the arms of all chairs in cabins further con-tributes to this phenomenon.

As a consequence of inadequately designed cabinsfrom the anthropometric aspect, as well as due to theexposure to the multiple stresses (including the influ-ence of vibration), operators are forced to work morecarefully, in order to perform the task accurately. Allthis affects that the workers basically work slower thanthey would otherwise do, and so they come to a situa-tion that they late with the execution of planned dailyactivities. This phenomenon influences that the opera-tors less often take breaks that are to them otherwisenecessary, which leads to their overload in some situa-tions.

However, such physical strain that mainly appearedas the result of application of improper design solu-tions has a negative effect on the appearance of the gen-eral state of fatigue, which after the certain time influ-ences the sense of mental fatigue, which reduces theability of perception of operators. Sense of responsibil-ity for the cargo that is transferred, as well as forcing interms of the execution of planned work quotas, in thepart of operators further contributes to the state of theoverall stress.

4.2. The analysis based on the use of checklists andinterviewing

Taking into account the results of the descriptiveanalysis, as well as the complexity of conditions in thecabin that have an impact on the operator, we chosethe checklist that was created by Kittusamy [11]. This

AUTH

OR

COPY


checklist was designed especially for the assessment ofthe design of the cabins of construction equipment, andit has shown acceptable repeatability. However, here itwill be presented the results that are obtained by apply-ing the part of the above-mentioned checklist, which isdirectly connected with the topic of this study. In thepurpose of obtaining the additional information aboutthe suitability of certain elements in the cabin for us-ing, the operators gave evaluations on the Likert scaleof five levels, relating to the issues in the checklist. Foreach cabin of a crane, at least one operator gave theevaluation.

Most complaints operators have had in relation tothe seat. In height, the seat might be adjusted only inone cabin (with crane 0.12 years of age). The positionof the chair height, the operators rated with the aver-age grade of 2.82. In connection with this, only twooperators have declared themselves that for them, theposition of seat in terms of the height completely cor-responds. In addition to the operator who was in thepossibility to adjust the seat in height, the other opera-tor who has estimated the position of the seat along thevertical axis with the highest grade was the operatorwhom the seat accidentally has corresponded, becauseof his anthropometric characteristics. Also, the chairmight be adjusted in the horizontal direction only inone crane (crane with 0.12 years of age). Only 17.6%of all seats in the cranes have adequate support for theback in the lumbar region. In 52.9% of cases, the slopeof the seat backrest cannot be adjusted, while the oper-ators rated with the average grade of 1.82 the adjusta-bility of backrest inclination. The possibility of turningof the seat, the operators rated with the average gradeof 1.94. However, the armrests did not possess evenone chair in the cabin.

The ease of the reach of manual controls in the cranecabin was rated with an average grade of 3.17. How-ever, considering the formulation of the question fromthe checklist “Can you easily reach the levers or con-trols?” [11], confidently we cannot know to what ex-tent in answer to this question the operators in consid-eration took the convenience (the easiness) of the reachin relation to the long-lasting work.

A general view of the working area, the operatorsrated with the average grade of 3.29. Respondents ratedwith the average grade of 4.05 the size of the cabin(overall dimension). With the highest average grade of4.23, respondents were rated the ease of use of footcontrols (pedals).

Application of the interviewing method did not re-veal much more information in relation to those that

were mentioned previously, in the sense of revealing ofproblems faced by operators at work. However, addi-tionally it would be worth to mention that the major-ity of operators have complained on the visibility fromthe cabin. This problem is particularly evident in somespecific situations of transferring of cargo. In addition,operators have complained about the fatigue, discom-fort and pain, which have mostly in the back, neck andshoulders. This phenomenon is more pronounced inoperators with longer working experience.

4.3. The anthropometric measurement

For collecting the data, we used the same proce-dure and identical instruments, which were used forthe anthropometric measurements that are describedin [12]. Taking into account that the main objective ofthis analysis is the research of anthropometric suitabil-ity of cabins of cranes and obtaining data that can beused for their afterward dimensioning (as well as forcreating of the layout in the cabin), it was presumedthat there are no fundamental differences between theanthropometric dimensions that should be included inthis analysis, and anthropometric dimensions that areused for assessment of the drivers’ workplace in a pas-senger vehicle. Accordingly, anthropometric variablesthat were presented in [12] for designing of passengervehicles, here were used as the basis for collecting dataon anthropometric characteristics of the crane opera-tors.

The following anthropometric dimensions weremeasured: stature, weight, foot length, sitting height,buttock-knee length, knee height in sitting position,bideltoid breadth, hip breadth in sitting position andarm length. Given that obtaining data for designingis one of the main goals of the anthropometric anal-ysis, all dimensions were measured with the work-ing clothes and shoes. In this way, for this purpose amore realistic data are obtained, contrary to the anthro-pometric data that would be obtained without work-ing clothes and shoes (which are particularly relevantfor design of clothing). All workers were wearing theworking clothes of moderate thickness (winter clotheswere not used). Such approach was also applied in theresearch that is described in [12].

In this case study participated 64 operators of cranes.All operators were male. The average age of operatorswas 46.6 years. Table 1 shows the standard deviation,5th, 50th, 95th and 99th percentile of the measured pa-rameters (dimensions are in the table header).

It should be noted that the population of crane oper-ators is relatively small population, which can be con-

AUTH

OR

COPY


Table 1The results of the anthropometric research on the population of crane operators

Dimension Stature Weight Foot length Sitting height Knee height Buttock-knee Bideltoid breadth Hip breadth Arm length(mm) (kg) (mm) (mm) (mm) length (mm) (mm) (mm) (mm)

Standard deviation 59.47 11.65 8.9 53.25 30.028 38.14 46.16 59.83 45.325th percentile 1650 65.3 249.4 806 529.7 551.4 391.75 295.2 615.450th percentile 1750 84 264 890 580 610 470 390 69095th percentile 1847.8 103.75 278.6 980.5 628.2 677.5 543.16 491.4 764.0599th percentile 1888.8 111.54 284.7 1017.27 648.9 702.8 575 532.6 795.3

Table 2The results of comparisons between anthropometric dimensions that were obtained on the sample of the crane operators from this case study, andthe sample of citizens of Serbia

Parameters of Stature Foot length Sitting height Knee height Buttock-knee length Bideltoid breadth Hip breadth Arm lengththe t test (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm)t 1.695 7.867 7.519 −9.521 2.938 2.236 −1.507 −1.946α = 0.05 A NA NA NA NA NA A Aα = 0.1 NA NA NA NA NA NA A NAα = 0.2 NA NA NA NA NA NA NA NA

sidered, in some sense, as a stratified sample. With thisin mind, it is necessary to determine whether in theterms of anthropometry, this population deviates fromthe general population. This information is addition-ally required, in order to be able to present the recom-mendations for designing of adequate cabins of cranesin the continuation of the paper.

In the purpose of this evaluation, it was necessary todecide which data to be used, in order to perform theaforementioned comparison. In Serbia, on several oc-casions, in different time intervals, anthropometric di-mensions of the samples of different sizes were mea-sured. One of the largest samples that was a subjectof the anthropometric measuring was from 1976. Allin all, the anthropometric measuring that is mentionedcoincides with the average age of the cranes, whichare the subject of this review (in other words, it canbe considered that at the time of the anthropometricsurvey one part of the equipment was new). However,we could not find the information, whether the cranesat that time were designed or purchased in accordancewith the anthropometric characteristics of the peoplein Serbia (research that is mentioned was related tothe design of passenger cars and did not address thecranes). Bearing the foregoing in mind and the factthat this is a statistically significant sample, a deci-sion was made about its selection for further analysis.The aforementioned sample of people from Serbia [12]contained 1838 males.

However, from the reason that the length of the armin the research from 1976 was not determined, for thepurpose of comparison of this anthropometric dimen-sion, the sample of humans from Serbia from 2004 hasbeen chosen in addition. The sample from 2004 in-

cluded 235 males [12]. This is also the biggest knownsample (with published data), within which the lengthof the arm was determined on population of subjectsfrom Serbia. Body weight is not the subject of compar-ison, since it does not affect the size and layout of thecomponents in a cabin of a crane.

Accepting the assumption that the basic sets fromwhich the samples of humans are selected are normallydistributed and that their variances are equal, for thepurpose of realization of comparison, we will use thet-test for independent samples. The test results are pre-sented in the concise form in Table 2. This table con-tains the calculated values for t, for considered anthro-pometric dimensions. The values for the level of signif-icance of the test are also presented, as well as the de-cisions on whether to accept or reject the null hypoth-esis. The initial hypothesis is related to the assumptionthat there is no statistically significant difference be-tween the anthropometric variables that are compared.In the table is marked with the label that the null hy-pothesis is accepted, while the NA indicates that thenull hypothesis is rejected.

From Table 2, it can be seen that on the level of sig-nificance of 0.05 (critical value for t is tcr = 1.96)it cannot be accepted initial hypothesis on equalityof anthropometric dimensions for sitting height, kneeheight in sitting position, buttock-knee length, bidel-toid breadth and foot length. From this table, it canalso be observed that for the level of significance of 0.1(tcr = 1, 645) it cannot be accepted the initial hypothe-sis about the equality of sizes for all anthropometric di-mensions that are compared, except for the hip breadth.Also, we see that for the level of significance of 0.2(tcr = 1.282), it cannot be accepted initial hypothe-

AUTH

OR

COPY


sis on equality of anthropometric sizes when we takeinto account all the anthropometric dimensions that arecompared.

5. Discussion of results

On the basis of the conducted research, as one ofthe most important items in the cabins can be markedthe working chair. Of their design in great extent de-pend factors such as comfort, health of workers, accu-racy during long-lasting work, as well as working per-formance. Adequately designed working chair allowsthe operator to take the most convenient working posi-tion in relation to the equipment, but also enables theoperator to position itself in a way that allows him tosee the cargo during a transmission (under the condi-tion that there are not other structural elements in thecabin that reduce visibility). Even if it was made anomission in designing, in terms of inadequate position-ing of controls and displays, ergonomically designedworking chair will alleviate or eliminate these short-comings.

One of the major deficiencies that has been recordedin all the studied cabins is the lack of support for thearms. This is a serious omission that additionally wors-ens the unfavorable situation for the operator, in a sit-uation where there is already an uncomfortable work-ing position dictated by the working task, and whichis conditioned by the existence of a chair that has alimited ability for adjusting. It can be assumed that themain reason for lack of the support for arms is an as-sumption of designers, that an existence of this aid onthe chair might have as a consequence the restriction ofmovements of the operators. However, if it is properlydesigned, the armrest will contribute to the less mus-culoskeletal strain, without substantial influence on thelimitation of movement.

6. Recommendations for designing

In this section, the recommendations for designingthe individual components within the crane cabin arepresented. These ergonomic recommendations can beused as a solution to the problems identified in thisstudy, in relation to the anthropometric incompatibil-ity of an operator and equipment in a crane cabin. Inaddition to some recommendations that are generallyknown, and which are very useful for designing thecertain components in the cabins of cranes (such as,

for example, some recommendations for chairs), thelists of recommendations that follow include some in-novative solutions, which so far have not applied in de-signing the crane cabins. Having above mentioned inmind, the basic guidelines for designers when design-ing chairs for the cabins of cranes are:

– Provide the adjustability of the chair in height (invertical direction).

– Provide the adjustability of the chair in depth (inthe horizontal direction).

– Provide the possibility of rotation of the chair forat least 270◦.

– Provide the adjustability in inclination of the seatpan.

– Provide the stability of the chair.– Provide the support for the arms.– Provide the adjustability of the backrest of the

chair (particularly in slope).– Provide that the slope of the backrest of the chair

can be fixed at a specific position.– Provide support for the lumbar area of the back.In relation to the layout of manual controls, the ba-

sic recommendations for designers when designing thecrane cabins are:

– Ensure the possibility of adjustability in positionof all controls.

– If due to constructional constraints, it is not pos-sible to ensure adjustability in the position of allcontrols in the cabin, then it should be ensured, asa minimum, adjustability in the position of con-trols that the operator most frequently uses.

– In conjunction with the previous two items, one ofthe best solutions is that the position of controlsfollows the change of the chair position, or theoperator.

– Provide stability of controls, as well as that theposition of controls can be fixed in space.

In order to prevent negative effects on the operator’sperception of a cargo that is transferred, it is necessaryto take into account the following recommendations:

– Most of the lateral parts of the cabin should bemade of transparent material.

– A significant part of the floor of the cabin shouldbe made of transparent material.

– A considerable part of the ceiling of the cabinshould also be made of transparent material (fromthe operator’s coronal plane, towards the front).

– Remove from the visual field of the operator allaccompanying elements of construction, and po-sition them in an area behind the operator (i.e. op-posite of the location of the cargo).

AUTH

OR

COPY


7. Conclusion

Three groups of effects have been identified, whichare the consequence of anthropometric incompatibilitybetween the operator and certain design characteristicsof a cabin and equipment in it. These are: effects re-lated to the influence that the anthropometric incom-patibility of the cabin has on the operator, effects onthe performance as well as financial losses of the com-pany, and effects on the safety.

Performed analysis indicates to the necessity of de-signing the crane cabin and positioning the equipmentin it from the anthropometric point of view. It has beenshown that analyzed crane cabins do not correspondto the operators from the anthropometric standpoint.However, conducted case study also points out to avery important omission that can be made, regardingdimensioning the cabin as a whole, including the po-sitioning of certain elements in it. The essence of theproblem is related to the selection of relevant anthro-pometric data that will be used for designing.

The conducted anthropometric analysis has been in-dicated that would be made the mistake, if dimensionsof the cabin and layout of equipment would be reliedon data derived from the general population of citizens.Already on the level of significance of 0.05, more than50% anthropometric dimensions have shown the dis-agreement, when the population of operators of craneshas compared with the general population of citizens,from the anthropometric viewpoint. At the level of sig-nificance of 0.1, 85.7% anthropometric dimensions ofthe total number of selected anthropometric dimen-sions have shown this kind of disagreement. On thelevel of significance of 0.2, the accordance betweenmentioned populations has not been established for noone of the anthropometric dimensions that were com-pared.

The proper selection of data from the anthropomet-ric point of view has the great influence on designingof the cabin and the equipment in it. If the data fromthe general user population are taken as a basis for de-signing, it is possible that the design solution will con-tain an error, which will be reflected in comfort, anddepending on the size of this error, it can be expectedother negative effects, such as effects on the health ofoperators, efficiency, safety and economic losses.

As the optimal strategy in terms of harmonizationof the man-machine system for designers can be rec-ommended the solution, where the anthropometric datathat are collected on the population of crane operatorswill be the basis for designing the new cabins. In most

cases, the population of operators who work in the cab-ins of cranes is not too large population, so its anthro-pometric measurement is practically possible. This so-lution would certainly be the most optimal for the cur-rent population of operators of cranes, as future usersof the new cabins. Through the content of instructionmanuals of cranes, may be additionally performed thespecification of percentiles, as the recommendation forthe selection of operators, who are best suited to workin a particular cabin, according to the anthropomet-ric characteristics. In addition, application of the er-gonomic recommendations for designing from the pre-vious section will further contribute to achieve harmo-nization between the anthropometric characteristics ofoperators and properties of the crane cabins.

Acknowledgements

We wish to thank the operators of cranes and com-panies that have participated in this study. This studycould not be completed without their cooperation andsupport in carrying out the research. Study is supportedby a fund of the Eureka E!6761 project.

References

[1] Ray PK, Tewari VK. Ergonomic design of crane cabins: Acase study from a steel plant in India. Work. 2012; 41: 5972-5976.

[2] Nordin F, Olsson S. Development of driver environment incrane cabin [M.Sc. thesis]. Lulea, Sweden: Lulea Universityof Technology, 2008.

[3] Naevestad TO. Safety understandings among crane opera-tors and process operators on a Norwegian offshore platform.Safety Science. 2008; 46(3): 520-534.

[4] Magnusson M, Hansson T. The effect of seat back inclinationon spine height changes. Applied Ergonomics. 1994; 25(5):294-298.

[5] Haynes S, Williams K. Impact of seating posture on user com-fort and typing performance for people with chronic low backpain. International Journal of Industrial Ergonomics. 2008;38(1): 35-46.

[6] Tam VWY, Fung IWH. Tower crane safety in the constructionindustry: A Hong Kong study. Safety Science. 2011; 49(2):208-215.

[7] Aneziris ON, Papazoglou IA, Mud ML, Damen M, Kuiper J,Baksteen H, Ale BJ, Bellamy LJ, Hale AR, Bloemhoff A, PostJG, Oh J. Towards risk assessment for crane activities. SafetyScience. 2008; 46(6): 872-884.

[8] Pratt SG, Kisner SM, Moore PH. Machinery-Related Fatali-ties in the Construction Industry. American Journal of Indus-trial Medicine. 1997; 32: 42-50.

[9] Oborne DJ. Ergonomics at work. Chichester, UK: John Wileyand Sons Ltd.; 1996.

[10] Sanders MS, McCormick EJ. Human factors in engineeringand design. Singapore: McGraw-Hill, 1992.

AUTH

OR

COPY


[11] Kittusamy NK. A Checklist for Evaluating Cab Design ofConstruction Equipment. Appl Occup Env Hyg. 2003; 18(10):721-723.

[12] Klarin M, Spasojevic-Brkic V, Sajfert Z, Zunjic A, Nikolic M.Determination of passenger car interior space for foot controlsaccommodation. Proc. IMechE Part D: J. Automobile Engi-neering. 2009; 223: 1529-1547.

AUTH

OR

COPY

Documents

wor-52-wor2042