Work-related Musculoskeletal Disorders and Ergonomics Improvement by Using ISO/TS

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1 Work-related Musculoskeletal Disorders and Ergonomics Improvement by Using ISO/TS Sudthida Krungkraiwong a, Toru Itani b, a National Institute for the Improvement of Working Conditions and Environment, Talingchan, Bangkok 10170, Thailand ( sudthida_krung@yahoo.com) b Nagoya City University Graduate School of Medical Science,Nagoya , Japan ABSTRACT: Work-related musculoskeletal disorders are becoming one of the occupational safety and health problems in Thailand. The statistics from the Office of Workmen s Compensation Fund showed that many Thai workers are suffering from musculoskeletal disorders. In 2003, the National Institute for the Improvement of Working Conditions and Environment (NICE) recognized the problem so NICE and Professor Toru Itani conducted a research study on Work-related musculoskeletal disorders and ergonomics Improvement. The study was conducted in 14 factories by using ISO/TS Ergonomic procedures for the improvement of local muscular workloads Part 1: Guidelines for reducing local muscular workloads as the guideline and participatory approach from the personnel concern in the factory. From the study by using Annex D of ISO/TS (Questionnaire for monitoring the effects and insufficiency of risk reduction measures concerning local muscular workloads), we found that part of the body that workers feel most painful are lower back. From the follow-up visit, we found that those factories that joined our Project could do various ergonomics improvement according to their future action plan Some ergonomics improvements could show benefit from the improve productivity, such as increase productivity, reduce musculoskeletal disorders (muscle pain/fatigue), increase ergonomics because of number of lift up and down was reduced, etc. Some of the improvement can increase productivities. Keywords: musculoskeletal disorders, ergonomics improvement, participatory approach. 1. INTRODUCTION Work-related musculoskeletal disorders are becoming one of the occupational safety and health problems in Thailand. The statistics from the Office of Workmen s Compensation Fund showed that many Thai workers are suffering from musculoskeletal disorders. In (5 years), there were 50,860 cases or average 10,172 cases per year that injured because of lifting heavy objects and working with awkward postures such as bending their back while lifting or working, raise their arms higher than shoulder level, etc. as shown in Table 1. Table 1: Occupational injuries caused by lifting heavy objects and working with awkward postures Year Number of occupational injuries (cases) , , , , ,767 Total 50,860 Average 10,172 The International Organization for Standardization (ISO) published a Technical Specification (TS), ISO/TS : Ergonomic procedures for the improvement of local muscular workloads Part 1: Guidelines for reducing local muscular workloads. This ISO Technical Specification was prepared by ISO technical working group (ISO/TC 159/SC 3/ WG 5) that Professor Toru Itani was the chairperson and ergonomics specialist from NICE was one of the working groups. The ISO/TS consisted of Annex A to Annex E as follows: Annex A: Schedule form for principles, plan and implementation Annex B: Checklist for hazard identification concerning local muscular workload Annex C: Action-oriented checklist

2 Annex D: Questionnaire for monitoring the effects and insufficiency of risk reduction measures concerning local muscular workloads Annex E: Evaluation form for the risk reduction activity The National Institute for the Improvement of Working Conditions and Environment (NICE) recognized the problem of work-related musculoskeletal disorders. NICE and Professor Toru Itani from Nagoya City University Graduate School of Medical Science, Japan conducted a joint research study on Work-related musculoskeletal disorders and ergonomics Improvement. 2. Material and Methods We started a joint research study project on Work-related Musculoskeletal Disorders and Ergonomics Improvement In 2003 by applying ISO/TS Ergonomic procedures for the improvement of local muscular workloads Part 1: Guidelines for reducing local muscular workloads as our guideline. We also used the participatory approach of the personnel in the factory, such as occupational safety and health committee, safety officer, supervisor, etc. in conducting our activities. Steps of our activities were as follows: a. Recruitment of the factories that would like to join our Project. We announced our Project in the written program booklet that distributed to all who came to visit in our 17 th National Safety Week, 9 17 May We also sent out the invitation letters to the companies that had problems on work-related musculoskeletal disorders. We got the list name of the companies and their address from the Office of Workmen s Compensation Fund. b. Discussion with the personnel in the selected company. We organized a meeting with the concerned personnel in each company. During our meeting, the activities were: (1) We explained the activities and objectives of our Project. (2) In case that company would like to join our Project, the companies should be willing to make ergonomics improvement. (3) The company had to set priority and selected one section/department to be model for our project activities. c. Conducted a study on work-related musculoskeletal disorders problems by using Annex D Questionnaire for monitoring the effects and insufficiency of risk reduction measures concerning local muscular workloads. We asked questionnaire to every worker in the selected section/department. For example, there were three shifts a day, we asked questionnaire to all three shift workers. d. Organized a workshop by using participatory approach of the concerned personnel. The activities during the workshop were: (1) We showed the detail of our activities in this Project, the Annex B D that used in the project, example photos of before and after improvement, etc. (2) We organized group discussion among concerned personnel to identify the ergonomics hazards by using Annex B Checklist for hazard identification concerning local muscular workload. (3) The company surveyed the ergonomics problems in the workplace to find the ways of improvements by using Annex C Action-oriented checklist. After completed the surveyed checklist, we organized group discussion to set up priority of the ergonomics problems that had to be improved in the workplace. (4) We organized group discussion amomg concerned personnel to discuss about company future action plans for ergonomics improvement by using information from d (2) and (3). In their future action plan, the company set up priority to improve occupational safety and health in their workplace. e. Follow-up visited the company to check whether the company could made the ergonomics improvement according to their future action plans or not. If they had any problems, we will give more suggestion. During the follow-up visit, we also collected information and photoes of before and after improvement. Some companies we visited for follow-up visit more than two times after they can made improvement. 3. RESULTS AND DISCUSSION There were 14 companies that joined our Project. By using Annex D asking workers in the model section/department about work-related musculoskeletal disorders problems, there were 1,077 workers answered our questionnaire. We found that lower back was the part of body that most workers were suffering from muscle pain/fatigue as shown in Table 2. 2

3 Table 2: Type of industry, number of workers that answered questionnaire and body part that had highest muscle pain/fatigue Type of industry Number of workers who answered questionnaire Body part that had highest pain/fatigue Sanitary Ware 223 Lower back Escalator / Elevator Manufacturing 166 Lower back Brake Manufacturing 164 Lower back Can Manufacturing 117 Lower back Aluminium Wheel 132 Lower back Steel Cabinet 30 Lower back Rubber Bicycle Wheel 22 Lower back Logistics 21 Lower back Medicine Manufacturing 10 Lower back Garment 47 Upper Back Textile 30 Hips / Thighs Snack 38 Upper back Carton (Paper Box) 19 Lower back Steel Cutting Machine 58 Lower back From the follow-up visit, we found that most companies could improve their workplaces according to their future action plans. A. Example of ergonomics improvements from the company that joined our project was from sanitary ware. This company selected polishing shop (buff work and belt work) in the production department to be the model to conduct ergonomics improvement by using ISO/TS as the guideline and participatory approach from the personnel concern in the factory. The activities were: (1) Conducting a study on work-related musculoskeletal disorders problems by using Annex D in the polishing shop 223 workers. We found that lower back was the part of body that workers feel highest muscle pain/fatigue while wrists/hand was the second muscle pain/fatigue. (2) Organizing a workshop and using Annex B identify the ergonomics hazards, Annex C to survey the ergonomics problems in the workplace and group discussion for future action plan, one of their priority future action plans for ergonomics was to improve chairs and footrest. Before improvement, the workers sat on the chairs without backrest with bending posture and footrests were not adjustable. Their improvement was to improve chairs with backrest and footrests could be adjustable. First, the company made 12 sets of chair with backrest and footrest could be adjustable, then asked 100 workers on satisfaction level about chairs and foot rests of before and after improvement about: - Appropriate or comfortable while sitting / chair dimension - Appropriate height of chair - Appropriate of back rest - Appropriate between chair and foot rest - Can reduce fatigue while sitting on chair with backrest The result from the questionnaire as shown in table 3: - Before improvement, the satisfaction level of the workers with chairs without backrest and footrests were not adjustable was in bad or fair level. - After improvement, the satisfaction level of the workers with chair with backrest and footrest can be adjustable was in good level. Table 3: Satisfaction level about chairs and foot rests of before and after improvement. Satisfaction level Before improvement After improvement Sitting / chair dimension Bad / Fair Good Height of chair Fair Good Backrest Bad Good Footrest Bad Good Fatigue reduction Bad Good 3

4 Figure 1: Before improvement - chairs without backrest, after improvement - chair with backrest Adjustable Figure 2: Before improvement - footrest was not adjustable, after improvement - footrest could be adjustable Finally, the company made 80 sets of chair with backrest and footrest could be adjustable for every worker as shown in figure 1 and figure 2. From the follow-up visit, we also found that the company could increase their productivity more than the target of 100 % as shown in figure % PRODUCTION DEPARTMENT POLISHING SHOP POLISHING Good Out Efficiency % TARGET = 100 % BUFF > 3 Mths BELT > 3 Mths JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Figure 3: After improvement, the company could increase productivity 4

5 This company after improved chairs and foot rests in the model section/department, they found the benefit from conducting this ergonomics improvement. So they spread this activity to all section/department in the factory. One of the ergonomics improvements was to put racks on wheels for easier movement as shown in figure 4. Figure 4: after improvement put wheels for easy move material The company also conducted a questionnaire asking about work-related musculoskeletal disorders problems by using Annex D with 15 workers. They found that after improvement, muscle pain/fatigue was reduced as shown in table 4. Table 4: Body part that feel pain/fatigue of before and after improvement Body part Score Increase + Before After Decrease - 1.Neck Shoulder Upper back Lower back Upper arms Elbow Forearms Wrists/Hands Hips/Thighs Knees Lower legs Ankles/Feet Average Remarks: 0 = not at all, 1 = slight, 2 = moderate, 3 = strong, 4 = excessive muscle pain/fatigue B. Another example of ergonomics improvements was from Escalator / Elevator Manufacturing. This company selected escalator department to be the model to conduct ergonomics improvement by using ISO/TS as the guideline and participatory approach from the personnel concern in the factory. The activities were: (1) Conducting a study on work-related musculoskeletal disorders problems by using Annex D in the 166 workers in the escalator department. We found that lower back was the part of body that workers feel highest muscle pain/fatigue while upper back was the second muscle pain/fatigue. (2) Organizing a workshop and using Annex B identify the ergonomics hazards, Annex C to survey the ergonomics problems in the workplace and group discussion for future action plan. From the follow-up visit, we found that there were many ergonomics improvement from various sections in the escalator department. One example of their ergonomics improvement was to improve plant layout in the floor plate assembly line in the escalator department as shown in figure 5. 5

6 BEFOR Before Reinforcement FLOW DIAGRAM FLOOR PLATE ASS Y LINE Back Side Plate AFTER After Back Side Plate FLOW DIAGRAM FLOOR PLATE ASS Y LINE Part Waiting Reinforcement Side Plate Decorative Plate Side Plate Decorative Plate Figure 5: Plant layout of before and after ergonomics improvement in the floor plate assembly line in the escalator department After the improvement, we found that result from the ergonomics improvement as shown in table 5 and were as follows: - Work in process (WIP) was reduced 150 sets (83%) - Delay time was reduced hours (78%) - Moving part distance reduced 17 meters (81%) - Operator was reduced 1 worker (25%) - Production area was reduced 608 square meters (33%) - Number of lift up and down reduced 3 times per piece that means ergonomics was increase Table 5: Difference about plant layout of before and after improvement Title Before improvement After improvement Difference Working in process 180 sets 30 sets Reduce 150 sets (83%) Delay time hours hours Reduce hours (78%) Moving part distance 21 meters 4 meters Reduce 17 meters (81%) Operator 4 workers 3 workers Reduce 1 worker (25%) Production Area 16.8 square meters 10.0 square meters Reduce 6.8 square meters (33%) No. of Lift up and down 9 times / piece 6 times / piece Reduce 3 times / piece (33%) 4. CONCLUSION From the study on Work-related musculoskeletal disorders and ergonomics Improvement, we found that lower back was the part of body that most workers were suffering from muscle pain/fatigue. The company that joined our project could do various ergonomics improvement in their workplaces according to their 6

7 future action plan. ISO/TS : Ergonomic procedures for the improvement of local muscular workloads Part 1: Guidelines for reducing local muscular workloads and participatory approach from the personnel concern in the factory were used in this project. Some ergonomics improvements could show benefit from the improve productivity, such as increase productivity, reduce musculoskeletal disorders (muscle pain/fatigue), increase ergonomics because of number of lift up and down was reduced, etc. So if the companies that workers suffering from musculoskeletal disorders conduct the ergonomics improvement in their workplaces, the company can get the benefit from their improvement. REFERENCES [1] (1998). Annual Report of the Workmen s Compensation Office Bangkok: [2] (1999). Annual Report of the Workmen s Compensation Office Bangkok: [3] (2000). Annual Report of the Workmen s Compensation Office Bangkok: [4] (2001). Annual Report of the Workmen s Compensation Office Bangkok: [5] (2002). Annual Report of the Workmen s Compensation Office Bangkok: [6] ISO. (2004). ISO/TS Technical Specification-Ergonomic procedures for the improvement of local muscular workloads-part 1: Guidelines for reducing local muscular workloads. ISO. 7