Pergamon Safety Science Vol. 26, No. l/2, pp. 75-85, 1997

0 1997 Elsevier Science Ltd. All rights reserved Printed in the Netherlands

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A PARTICIPATORY ERGONOMICS APPROACH TO REDESIGN WORK OF SCAFFOLDERS

Peter Vink ‘9 * , //se J. M. Urlings a, Henk F. van der MO/en b

a NIA TNO, P.O. Box 75665, 1070 AR Amsterdam, The Netherlands

b Stichting Arbouw, P.O. Box 8114, 1005 AC Amsterdam, The Netherlands

Abstract-A step-by-step approach to better work, aimed at reducing physical workload among

scaffolders, is evaluated. The approach is based on a strong commitment of the management in

the enterprise. Workers participated as direct as possible. Information on branch level of

Arbouw showed the need for improvement, In a department of a middle-sized enterprise, 50

scaffolders completed a checklist to identify the problems. These determined the user require-

ments for the redesign of the working methods. Redesign proposals of TN0 were tested by the

workers. Based on the test a steering group led by the management chose the improvements.

Before implementation, the effect on musculoskeletal load was tested, and half a year after

implementation the number of changes and the process were evaluated. The shoulder com-

plaints and physical work load during horizontal and vertical transport were the major problems.

The main improvements were mechanizing the transport, decreasing the loads and organizing

the work in another way. Due to these changes the musculoskeletal load was significantly

decreased, especially on the shoulder. Only 26% of the subjects responded to the evaluation on

the number of improvements after half a year. These data indicated that for the major problems

improvements were implemented, which reduced the physical workload and the perceived

shoulder- and backpain. The process evaluation indicated that the approach was considered

worthwhile, especially regarding the involvement of scaffolders themselves. 0 1997 Elsevier

Science Ltd.

1. Introduction

Heavy manual handling during more than two hours a day is reported by 30% of the

European workers (Paoli, 1992). This is a major risk factor for musculoskeletal injuries (Hildebrandt, 1987). Therefore most companies agree that there is certainly room for

improvement in working methods. However, changing the working methods can be very difficult. Sometimes the workers do not see the necessity, sometimes these are too costly, or sometimes workers may refuse to use new working methods. Next to difficulties in imple-

menting, it is of importance to find the most appropriate improvement(s) aimed at reduction of

76 P. Vink et al.

the major problems. To redesign the working methods in the most appropriate way and to increase the chance of successful implementation a special approach was developed. Based on

several studies (Cotton et al., 1988; Hugentobler et al., 1992; Kogi, 1985; Noro and Imada, 1992; Vink et al., 1992; Vink and Kompier, 1991; Vink and Koningsveld, 1990) the

participatory ergonomics approach to reduce the physical workload was developed. A strong

commitment of the management in the enterprise and an as direct worker participation as

possible are essentials of the approach. The purpose of the present study was to apply and evaluate this participatory ergonomics (PE) approach.

The PE-approach was applied in two scaffold building companies. Previous studies on

branch level showed that s&folders have a physically demanding job (Arbouw, 1991) and improvements are possible (van der Molen et al., 1993). Arbouw (the Dutch institute for

improving the working conditions in the construction industry) and TN0 (the applied

scientific research organization in the Netherlands) guided this project. In this paper the process in the large company is described.

2. Methods

2.1. The PE-approach

Essential in the PE-approach is that step-by-step all participants (of the company as well as

the advisors) progress towards the end-result (reduction of physical workload). After every step in the process all participants are informed. All s&folders completed checklists,

developed suggestions for improvements, tested improvements and gave their preference. The

results of these recordings were discussed with them as well as with the foremen, because they have a better view on the feasibility. The headlines, costs and benefits were discussed in a steering group chaired by the manager of the department. The steering group decided for

instance on what improvements were possible before asking the scaffolders to give their preference.

The PE-approach contained the following steps:

2.1.1. Step I. Preparation In this step all scaffolders were informed about the project during a central meeting. The

aim of the project (better working conditions), strategy (step-by-step approach), members of a steering committee and possible outcomes were presented by the consultant of TNO.

2.1.2. Step 2. Analysis of work and health In this step a checklist was completed by the scaffolders in order to identify special risk

factors and risk tasks regarding the physical workload, that should be tackled in the redesign. Previous research among scaffolders (Arbouw, 1991) showed that physical workload was the largest problem. Accidents due to falling are also mentioned as a problem, but various measures are already implemented. Furthermore, the assumption is that fatigue influences the risk on accidents. Therefore a checklist focused on physical problems was made to find the special problems among the 50 scaffolders and foreman in this department. Questions on duration of the tasks, on the experienced heaviness of the tasks and on complaints in the body parts were part of the checklist.

A participatory ergonomics approach to scaffolding work 7-l

2.1.3. Step 3. Selection of improvements

Based on the analysis user requirements were made for the largest hazards and largest risk

groups. These user requirements indicated the solutions that should be developed and selected. In a ‘solution sessions’, following a procedure described in detail elsewhere (Urlings et al., 1994a,b), ideas for improvements were generated. Essential in the method is that based on the user requirements, experts and scaffolders report ideas for improvement of each task. From

this list the steering group selected those improvements that could be realized within the

company. The scaffolders were then asked to give a score from 0 to 10 for the selected improvements. This was done during a meeting where a video of the problems and drawings of the improvements were shown.

2.1.4. Step 4. Pilot-study with the improvements

The improvements were tested by 6 s&folders (Arbouw, 1994; Urlings et al., 1994a.b)

during the building of a middle-sized scaffolding, that took one day. Two teams of three scaffolders built this scaffolding in the traditional and in the improved way. The tasks, heart

rate (Arbouw, 19941, posture, weights (Arbouw, 1994) and the locally experienced discomfort

(Van der Grinten, 1991) were recorded in both the traditional and the new situation. The tasks were recorded by an observer dictating start and end of the task on a voice recorder (accuracy

+ 10 s). Heart rates of the subjects were recorded with a Sporttester (PE3000, Polar Eleatro KY, Finland) every 15 seconds. Mean heart rates were calculated for each task end break, and

for the complete day. The posture and weights were recorded by TRAC (Task Recording and Analysis by Computer; Ridd, 1987) Every 15 seconds 2 observers recorded tools, materials,

aids, whole body posture, weight, and posture of the back and shoulder. Locally experienced

discomfort was recorded before and after every working period (4 working periods in a day

due to 3 breaks). In a body map subjects scored the height of the discomfort (0 4 no discomfort; 10 extreme discomfort) in different regions of the body.

Next to the measurements, the scaffolders were asked about their experience with both working methods. Then, adaptations to the improvements were made, if necessary.

2.1.5. Step 5. Implementation

In this stage the improvements are implemented into the actual workplaces. Since the improvements were selected based on the preference of the workers, this stage is the facilitation of the realization by promotion, training and instruction. In this step new

equipment was bought and materials were adapted and new appointments with the commis- sioners were made. Instruction videos were made including working methods with reduced

physical workload. In this video safety was also incorporated in alignment with the existing

policy of the company. In a central meeting all scaffolders and foreman were informed about the new situation and all scaffolders had a training in lifting objects.

2.1.6. Step 6. Evaluation This step should provide information about the effectiveness of the measures and indicate

whether adaptations or additional measures are needed. Half a year after the implementation a questionnaire was sent to the s&folders. The questions concerned the percentage of scaffold- ers using the new working method and how they judged the improvement. Also, the process of change was object of study to optimize the approach in new projects.

78

2.2. Subjects

P. Vink et al.

The approach is applied in a large enterprise (1200 scaffolders) involved in scaffolding.

The company works in construction as well as oil and steel industry. This paper concerns the process of redesign at a department of 50 scaffolders working in the steel industry.

3. Results

3.1. Results of step 2. Analysis of work and health

All scaffolders and foremen (50) completed the checklist. The tasks ‘leveling of the ground’, ‘sorting the materials’, ‘horizontal transport’, ‘vertical transport’, ‘building’ and ‘breaking down’ consumed most of the time. Problems in these tasks were: * Materials were set out in the wrong order. - The walking distance between the set out materials and scaffolding is too long. * Manual vertical transport of materials along the scaffolding is heavy work. - Materials were too heavy (especially long ladders, long boards and long pipes).

The s&folders complained about the heaviness of the job, which was already known from previous studies (Arbouw, 1991).

Compared with 7000 other Dutch labourers the scaffolders reported many shoulder complaints (see Fig. I). Other musculoskeletal complaints were also higher in number, but the difference was not that impressive.

In the discussion with the workers the abovementioned results were stressed. Furthermore, the workers reported that cleaning the scaffoldings before breaking them down is a heavy and dirty task, which should be eliminated as well.

neck

schoulder

elbow

wrist

UPP back

low back

hip

knee

ankle

0 10 20 30 40 50 60

%

n 7000 Dutch workers

Fig. 1. Percentage of the scaffolders reporting complaints during the last 12 months compared to a reference group of

7000 Dutch workers @NO-PG, 1995, unpublished data).

A par 7icipatory ergono mics approach to scaffolding work 19

pallet truck

WOlk?y

electr. winch

rope and wheel

ladders c3m

boards <4m

setting out materiats

clean scaffoldings

work preparation

task rotation

instruction

shoulder protectiin

rucksack for poles ah

0 2 4 6 8 10

Fig. 2. Average score of the s&folders and foremen for the different improvements (0 = bad: 10 = perfect).

Based on these data the steering committee decided to develop improvements aimed at reducing the load during cleaning, manual horizontal and manual vertical transport, especially focused on a reduction of the energetic loading and the shoulder load.

3.2. Results of step 3. Solution choice

During the meeting where the suggestions for improvements were discussed, the following improvements (see Fig. 2) scored best and were therefore chosen to be implemented:

Maximum length of ladders 3 m. Longer ladders are heavy and difficult to manoeuvre.

The commissioner should clean the scaffolding. Cleaning of the scaffolding before breaking it down was heavy and dirty work and not a specialism of the scaffolders. Therefore new contracts were made with the commissioners.

Other improvements that had a high score were:

Development of a pallet truck (see Fig. 3). Important requirements were: large wheels for uneven surfaces, should be arranged like a pallet, should pass hedges and doors.

Buying electrical winches (see Fig. 4). These winches should eliminate the manual vertical transport along the scaffolding.

Fig. 3. The pallet truck that was tested in the pilot-study. With this truck the manual horizontal transport with the

materials on the shoulder was eliminated.

80 P. Vink et al.

Fig. 4. The electrical winch raises the materials and eliminated raising manually.

Maximum length of boards 4 m. Boards of 5 m are too heavy (> 30 kg), especially when these are wet.

Setting out of materials in the right order, close to the spot where the scaffolding will be bui2t. The scaffolders previously had to rearrange the delivered materials before building, because the materials they needed first were positioned on the bottom of the pallet. Furthermore, the horizontal travel distance to the spot where the scaffolding should be built was too large.

A plan to prepare the work. Part of this was an unloading plan (see Fig. 5), which for instance shows what materials should be unloaded on what position to reduce the horizontal transport.

Shoulder protection in the clothing. Although horizontal transport will be eliminated as much as possible, carrying materials on the shoulder will still occur. To enlarge the contact area on the shoulder and to make the clothing waterproof a protection is added.

unloading bay I

unloading bay 1

unloading unloading

bay 2 bay 3

Fig. 5. Left: the old situation, which results in much manual carrying due to assorting and due to manual horizontal

transport. Right: an unloading plan; this results in the right materials close to the spot where the scaffolding will be built and reduces assorting and manual carrying.

A participatory ergonomics approach to scaffolding work 81

heartrate averaged over 4 sub]ects (beats per minute)

r**, ,n*,

mold %new

Fig. 6. Heart rate averaged over 4 scaffolders in the old and new working method (s = significantly different; ns = not

significantly different; paired t-test; p < 0.05).

3.3. Results of step 4. Pilot-study with the improuements

The heart rate decreased significantly in the new working method (see Fig. 6), which indicated less heavy work with the new working method. This is supported by observations.

The percentage of time that the scaffolders were observed with weights of more than 20 kg in their hands was also drastically decreased (see Fig. 7). There was also an indication that the

shoulder load was decreased. An elevation of more than 60” during a certain period of time

increases the risk of shoulder problems (Delleman, 1994). The percentage of time that the

K

30

old method new method

w manual carrying ~20 kg % manual raising ~20 kg

Fig. 7. Percentage of the time that the s&folders are observed with more than 20 kg in their hands during the old1 and

new working method.

82 P. Vink et al.

K of the lime s SO degrees arm elwellon

351

m hor transport s varl Iransport n assembling

Fig. 8. Percentage of the time that the scaffolders are observed with an arm elevation of more than 60” during the old

and new working method.

loul experienced discomfort 21

”

shoulder back lass

Fig. 9. The locally experienced discomfort averaged over 6 s&folders during the old and new working method

(0 = no discomfort; 10 = extreme discomfort).

shoulder was elevated more than 60” was also lower in the new situation (see Fig. 8) and the discomfort was also improved in the shoulder area (see Fig. 9).

This test showed that the improvements decreased the heaviness of the work and the shoulder load. However, heart rate and shoulder posture showed that the assembling still is heavy work, that needs to be improved in future projects. Because of the positive effects it was decided to implement these improvements. Improvements nrs 2, 7 and 8 were also implemented, but without test (as was decided by the steering group). Furthermore, it was decided to add a training ‘how to lift objects safe’ by the occupational health services.

A participator?, ergonomics approach to scaffolding work 83

Table 1

Percentage of the scaffolders working with the improvements, and judgement of these scaffolders half a year after the

study

Improvement Percentage scaffolders working

with the improvement

(n= 13)

Judgement of the scaffolders

working with the improvement

Pallet truck

Shorter ladders/boards

Electrical winch

Clean scaffolders

Well set out materials

Work preparation plan

Shoulder protection

Lifting training

88% 88% 30% 53% 30% 30% 88% 53%

good-very good good

good

fair

fair

fair

moderate

bad

3.4. Results of step 6. Evaluation

Only 13 out of 50 scaffolders completed the questionnaire. The s&folders reported that

shorter ladders, shorter boards, the pallet truck and the shoulder protection were implemented (see Table 1). 53% reported that cleaning of the scaffoldings before breaking them down was better and that they followed the training ‘how to lift objects safe’. 30% of them worked with

the electrical winch, better setting out of materials and the preparation plan. Most improvements were judged positive as they decreased the heaviness of the work. The

shoulder protection and lifting training were not judged positive. The scaffolders did not

expect much effect of these two measures.

The approach was also judged positive and 60% of the scaffolders judged that they had

enough influence.

4. Discussion

Participatory ergonomics is a relatively new approach (Noro and Imada, 1992), in which ergonomists are more change-agents (Imada, 1994) then scientists. A role that was performed

also in this study by the ergonomist. The concept of change-agents is already discussed in other disciplines by for instance Bennis (1966). Essential in the concept of change-agent is that the changes will be made by the participants. Even in 1948 Coch and French (1948)

already showed effects of participation. In the ‘control group’ of a USA pyjamas production factory, where change was introduced from above, production fell by 10 to 20%. In the ‘study

group’, where all employees were involved by discussing on the changes, the production immediately increased. The same study was repeated in Norway (French et al., 1960) in a factory that just had modernized its production making some workers redundant. Participation did not increase productivity in this case. Therefore, participation will not have an effect if it works against the perceived interests of the employees. Bemoux (1994) also shows that it is important that employees play a real role in introducing and testing improvements. They will only support those improvements of which they are fully convinced.

In our study the same tendencies were found. The stepwise approach with strong enterprise participation resulted in various implemented improvements, but two improvements that had

84 P. Vink et al.

not the interest of the scaffolders (shoulder protection and training) or on which they are not fully convinced were not judged positive.

A new element in participatory ergonomics the stepwise approach (Vink et al., 1992) was evaluated positive. The steering group experienced the step-by-step approach to he worth- while, because it structured the process and gave feed forward information. Feedback was judged to be worthwhile because it makes the participants aware of the reasons why choices are made and on why these specific improvements are needed. Feedback in meetings also gave the opportunity for the workers to influence the process.

Apart from the strategic point of successful implementation, worker involvement also leads to additional improvements. Without worker participation the additional idea like cleaning of the scaffolding before breaking it down was not developed.

Drawbacks of this specific study were the limited evaluation and discovering the relatively high load during the assembling at the end of the project. In this study the evaluation phase should have had more attention: the response was too low to judge effects on complaints. Perhaps a discussion on the results of the evaluation would stimulate the implementation more. By more direct participation in this phase more improvements could be implemented due to for instance communicating positive experiences with the electrical winch. It is better to evaluate effects on the long run. However, the pilot showed positive effects on heaviness and on shoulder load and it is expected that this will endure on the long run. However, this still needs to be investigated in the real work situation as well as the expected decrease in shoulder complaints and sick leave on the long run.

Furthermore, this study shows that the assembling of the scaffolding still is heavy work that needs attention in future projects.

5. Conclusion

‘Ihe PE-approach is effective in implementing improvements aimed at reduction of physical workload, It is important that workers participate in the whole process of change: to have workers identify the problems and develop ideas for improvement in cooperation with managers. As a result of discussions with all workers, it was chosen to focus on horizontal and vertical transport and to improve the shoulder load and heaviness of the work. For these problems improvements were implemented. It is expected that these improvements decrease the number of shoulder complaints and the sick leave. However, the effect on the long run still needs to be investigated.

Acknowledgements

The authors want to thank Arbouw for financing this project and SSH and Matab for making this research possible.

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