Ergonomics in the Carpet-Weaving Industry in Iran

Transcription

1 15 Ergonomics in the Carpet-Weaving Industry in Iran Majid Motamedzade CONTENTS 15.1 Introduction Conditions of Work in the Carpet-Weaving Industry Work Risk Factors in Carpet-Weaving Industry Awkward Postures Repetitive Nature of Tasks Force Contact Stress Poor Lighting Poor Ambient Conditions Poor Air Quality Chemicals Lack of Work Rest Regime Ergonomics Solutions for the Carpet-Weaving Industry Ergonomics Design of the Carpet-Weaving Workstation Ergonomics Design of Carpet-Weaving Hand-Tools Conclusions References Introduction Weaving is as old as civilization. Beside the need to design a suitable mat to sit or sleep on, primitive humans acquired more creative skills such as basket weaving using pliable grasses and barks, with the nests of birds and interwoven stems of plants being the creative patterns directing humans to weaving. Women were those who engaged themselves in this occupation, producing mats, saddles, and carriage bags. Not much is known about the world s first knotted carpets, and what does exist was acquired by means of conjecture and assumption. In the past, European researchers believed that successive Egyptian civilizations were the pioneers of carpet weaving. Even Iranians cannot claim to have produced the first handwoven carpets, but early evidence, in the form of a carpet named Pazirik, proves the role of Iranians in developing this valuable art. Today the Persian carpet is an essential part of Persian art and culture, and a sought-after commodity worldwide. Carpet weaving is one of the most distinguished manifestations of Persian culture and art, and dates back to ancient Persia. At present in Iran, apart from its 253

2 254 Ergonomics in Developing Regions: Needs and Applications historical background, the carpet-weaving industry as an informal sector enterprise ranks foremost in importance and size among other Iranian handicrafts. Handwoven carpets are the most important Iranian nonoil related export products and have an out standing place in the country s economy because of its share of 1% in gross national product (GNP) (Mahdavi, 2000). There are nearly 2.2 million full- and part-time weavers, and about 8.5 million people directly or indirectly live from the handwoven carpet industry in Iran (Sobhe, 1997). In 1999, the carpet export business comprised over 20.5% of the total nonoil export of the country (Mahdavi, 2000). Turning to the conditions under which these carpets are woven it is generally acknowledged that in setting priorities for health services consideration must be given to (a) the size of the population at risk and the degree of morbidity, and (b) extent to which a particular program contributes to overall socioeconomic development, its effectiveness, feasibility, cost, and relative urgency (Noweir, 1986). Considering these factors and the widespread nature of the carpet industry in the country, the economic importance of the industry, the role of the industry in generating employment and the sociocultural value of the industry, it may be concluded that in Iran, as in other developing countries, attention to the handweavers occupational health and to the improvement of their working conditions should be a major priority. The carpet industry has a considerable effect on the production, economy, quality of life, and sustainable development of the nation. This chapter outlines occupational health and work problems in our carpet-weaving industry. It proposes to review the risk factors in the industry and to present the latest adopted ergonomics solutions Conditions of Work in the Carpet-Weaving Industry The author of this chapter, in his teenage years, had first-hand experience in carpet weaving as it was his father s job, and he can therefore personally attest to the suffering of carpet weavers, especially young girls and boys. The inherent beauty of handwoven Persian carpets is consequently less apparent to the author than it probably will be to the reader. Carpet weaving is a family-based job and handwoven carpets are mainly produced in home-based workshops, and in limited cases in weaving factories, where a number of weavers are gathered to produce carpets. A carpet loom is the most important element in the weaving operation. Looms are of two types, horizontal and vertical. Horizontal looms pose a number of hazards and fortunately are less common. However, vertical looms, which are recognized as safer, create problems too. Weavers perform their job sitting on a bench or on the ground. When the ground is the seat, weaving is done in a cross-legged position. In the case of fixed vertical looms, as weaving progresses, the weaving height increases. In this situation the weaver has continually to place the seat in a higher position. The result is that when the seat is high the weaver s legs hang down unsupported. Sometimes, to prevent this, the weaver sits cross-legged on the seat. In some cases the seat is covered with soft materials, but in other cases it is not, as is evident in Figure While weaving a carpet, threads are held with the nondominant hand, and with the dominant hand another thread is passed between the loom threads and is then knotted. Afterwards the tip of the knot is cut with a knife, held in the dominant hand (see Figure 15.2). After two or three rows of knots have been tied the rows are compressed with an iron comb. Finally, to obtain a smooth surface, the threads are cut with scissors. The hand-tools used

3 Ergonomics in the Carpet-Weaving Industry in Iran 255 FIGURE 15.1 A typical vertical carpet-weaving loom. FIGURE 15.2 Typical hand and finger postures during carpet weaving.

4 256 Ergonomics in Developing Regions: Needs and Applications FIGURE 15.3 The scares of surgical intervention for carpal tunnel syndrome (CTS) which is a common repetition strain injury among carpet weavers. in carpet weaving are traditionally designed and no ergonomics principles were applied to their structure. Due to the poor design of weaving hand-tools and the inappropriate material used in their structures, several parts of the weavers hands and fingers bear contact stresses which may cause soft tissue injury. As extensive use of hand-tools is a key issue in the development of upper limb musculoskeletal disorders (Figure 15.3), ergonomics improvements of these hand-tools may promote improved health and safety among carpet weavers. Raw materials used in carpet weaving are mainly wool and threads. Sometimes these materials are of low quality or are infected with biological agents which produce health problems for the weavers. In addition the weaving workshops, which are mainly homebased, are small and cramped and generally lack adequate lighting, ventilation, cooling, and heating systems. The weavers, who are mostly women, earn low incomes and their education is mostly at a primary level. Working hours in the carpet industry are not fixed and they vary based on the situation and workload. Moreover, motivation to earn more money results in the weavers working long hours (Choobineh et al., 2003) Work Risk Factors in Carpet-Weaving Industry Awkward Postures Due to poor design of hand-tools, weaving workstations and looms, the postures of the neck, back, shoulders, upper and lower arms, wrists, and knees deviate from the neutral position for considerable periods of time leading to a high incidence of musculoskeletal injuries. Due to there being no leg clearance when using vertical looms, the weaver is

5 Ergonomics in the Carpet-Weaving Industry in Iran 257 forced to work cross-legged or in other fixed leg positions. In this situation, because there is no space for leg movements, the weaver cannot adjust her working posture in an attempt to alternate the postural stresses over different regions of the lower extremities. In a study of 1020 weavers, Choobineh et al. (2003), found the percentage of weavers who adopted suboptimal postures in the upper arm, lower arm, neck, trunk and leg to be 88.6%, 57.6%, 82.8%, 85.9% and 69.5%, respectively Repetitive Nature of Tasks Weaving is a highly repetitive task, in which a regular weaver ties up to 30 knots per minute. During all steps of weaving, the wrist and finger flexors and extensors are used continuously, with pinching movements and forceful grasping actions. If it is assumed that the weaver works for 8 h a shift and the weaving task comprises 60% of the total working time, there will be 8640 knots tied per shift. Since these highly repetitive tasks have a cycle time of 30 s or less, weaving is categorized as a highly repetitive job (Choobineh et al., 2004) Force The weight of a weaving comb, in some cases, is more than 2 kg. As the weaver has to compress the knots by using the comb at regular intervals, its weight and repetitive application under poor postural conditions can and does result in upper limb disorders Contact Stress Given the poor design of weaving hand-tools and the inappropriate materials used in their structure, many localized parts of weavers hands and fingers bear contact stress, which is likely to cause injury to the soft tissues of the hands Poor Lighting Carpet weaving is considered as precision work, for the knots are very fine and close together, and color recognition is of vital importance. Such operations require adequate lighting both qualitatively and quantitatively. In many weaving workshops, lighting is not adequate, which results in considerable eye strain, and in conjunction with this the insufficient lighting adds to the already awkward postures, as weavers are forced to incline their heads, necks, and backs to be able to look closer at their work Poor Ambient Conditions Lack of cooling and heating systems in weaving workshops results in poor thermal conditions. This improper environment will have adverse effects on the well being of the weavers, and consequently on their performance Poor Air Quality In the operation of wool preparation, combing knots and cleaning the workshop, wool fibers are produced and released into the atmosphere. Lack of proper ventilation in the workshop causes the weaver to be exposed to these fibers which increases the risk of respiratory diseases. Contamination of fibers with biological agents such as bacteria and fungi results in respiratory exposure to these agents and threatens the health of the weaver.

6 258 Ergonomics in Developing Regions: Needs and Applications Chemicals Some dyes used in wool preparation are toxic (e.g., chromate-based chemicals). Skin exposure to such toxic chemicals causes skin diseases and dermatitis (Radjabi, 1983). Biological agents such as anthrax bacillus can enter the body and produce infectious skin diseases as well Lack of Work Rest Regime Because there is no scheduled working time, weavers usually work continuously for long periods without rest pauses. The outcome of this prolonged exposure to the numerous occupational risk factors sited above increases the likelihood of the weavers experiencing extreme physical stress Ergonomics Solutions for the Carpet-Weaving Industry Ergonomics Design of the Carpet-Weaving Workstation Choobineh et al. (2007) proposed a model ergonomics carpet-weaving workstation. They conducted a comprehensive study which consisted of two phases. In the first phase, the incidents of musculoskeletal symptoms in nine Iranian provinces were surveyed by means of distributing a questionnaire to 1439 weavers, and working postures and weaving workstations were ergonomically assessed. The results of this phase revealed that problems associated with the musculoskeletal system were high. It also identified the design shortcomings of the weaving workstations. In the second phase of this study, an adjustable workstation was designed and constructed. The results of laboratory simulations showed that working postures were acceptable when the weaving height was adjusted to be 200 mm above elbow height and when a high seat with a forward slope was used. By combining the results of the two aforementioned phases, guidelines for a weaving workstation design were presented. In this ergonomically designed workstation, the loom is vertical with the seat, loom and weaving heights made adjustable, allowing enough leg room under the loom. The recommended workstation should improve the weavers working posture, thereby reducing the postural stresses placed on the their bodies and, consequently, should reduce the prevalence of musculoskeletal problems Ergonomics Design of Carpet-Weaving Hand-Tools Motamedzade et al. (2007), with experience in the field, proposed ergonomically redesigned hand-tools for carpet weaving. This study was conducted to investigate the design of hand-tools currently used in the carpet-weaving operation and, using sound ergonomics principles, to design or redesign the tools based on anthropometric dimensions of the workers and the tasks carried out. The study consisted of two phases, in the first of which 862 weavers from three Iranian provinces participated. A questionnaire consisting of personal details, a Nordic Questionnaire for upper limbs and a table for anthropometric dimensions of the hand were used to collect the required data. Based on the results of the first phase, prototypes of the hand-tools were made and were illustrated in Figure As shown in Figure 15.5, a nonslip texture was used to improve the grips so increasing

7 Ergonomics in the Carpet-Weaving Industry in Iran 259 FIGURE 15.4 A collection of carpet-weaving hand-tools. For the most common tools, prototypes were designed and tested. FIGURE 15.5 Weaving comb; left: traditional design, right: comb with redesigned handle.

8 260 Ergonomics in Developing Regions: Needs and Applications FIGURE 15.6 Weaving knife; top: traditional design; bottom: knife with new ergonomic handle. the friction between the hand and the handle of the weaving comb. The comb handle was oriented in such a way that while working no significant deviation from neutral posture occurred. Figure 15.6 demonstrates that an appropriate nonslip texture was used to improve the grip of the weaving knife. The guard on the sharp edge prevented slippage of the hand over the blade resulting in safer use of the knife. The rounded end of the handle was extended out of the closed hand, resulting in stress reduction on the palm. In the original tool no groove was provided to accommodate wide variations in finger anthropometry of the users. An appropriate texture was used to prevent slippage and to reduce contact stress on the hand and fingers during work with weaving scissors. This can be seen in Figure The scissors handle was oriented such that during work the wrist was held in a neutral posture and no significant deviations from this ideal position occurred. The rounded end of the handle was extended out of the closed hand, which lead to stress reduction on the palm. Figure 15.8 shows the weaver s hand posture while working with the weaving scissors. In this study, in order to assess comfort and applicability of the designed hand-tools and the weavers perceptions of the new design, a usability test was conducted. Ten experienced weavers participated in this test. Statistical analyses revealed significant differences between the scores of the old, and the newly designed tools (Motamedzade et al., 2007). There was a significant preference toward the comfort and applicability of the prototypes. The new ergonomically designed weaving hand-tools were found to be applicable and acceptable by the carpet weavers.

9 Ergonomics in the Carpet-Weaving Industry in Iran 261 FIGURE 15.7 Ergonomically designed weaving scissors. FIGURE 15.8 Weaver s hand posture during work with the weaving scissors prototype.

10 262 Ergonomics in Developing Regions: Needs and Applications 15.5 Conclusions Personal experiences of the author and others cited show that musculoskeletal problems in the hand-weaving carpet industry occur at a high incidence rate. Thus, improvement of working conditions and control of musculoskeletal risk factors is essential. Since the majority of factors for developing musculoskeletal problems among weavers are attributable to poorly designed weaving workstations and tools, any ergonomics interventional program should be directed toward their design. Finally, in industrially developing countries, great efforts are directed toward encouraging the development of small-scale industries as an engine for growth in their economies. If the carpet industry is supposed to work as a powerful engine to bring positive economic outcomes for countries where it is a key industry, it should receive appropriate attention from different viewpoints, above all ergonomics. Given this, as the carpet industry, like other informal small-scale industries around the world, faces serious problems such as lack of registration and monitoring, lack of legislative support, exclusion from health and safety acts and regulations, low capital resources and income, and finally low priority of health service planning, it seems that intervention programs for improving working conditions in the carpet-weaving industry in developing countries, need local government involvement, and should be planned, sponsored, and implemented by the governmental organizations responsible for occupational health and safety affairs, in cooperation with national/regional ergonomics societies. References Choobineh, A., Lahmi, M. A., Hosaini, M., Jamali, M., and Z. Rezaee Gorji Musculoskeletal problems and corrective measures in Iranian hand-woven carpet industry. In: Proceedings of the XVth Triennial Congress of the International Ergonomics Association and the 7th Joint Conference of Ergonomics Society of Korea/Japan Ergonomics Society. Seoul, Korea: Ergonomics Society of Korea. Choobineh, A., Shahnavaz, H., and M. A. Lahmi Major health risk factors in Iranian hand-woven carpet industry. International Journal of Occupational Safety and Ergonomics (JOSE) 10: Choobineh, A., Hosseini, M., Lahmi, M. A., Khani Jazani, R., and H. Shahnavaz Musculoskeletal problems in Iranian hand-woven carpet industry: Guidelines for workstation design. Applied Ergonomics 38: Mahdavi, H What should be done for Iranian carpet export? Kayhan [a newspaper] 16940:5 (in Persian). Motamedzade, M., Choobineh, A., Mououdi, M. A., and S. H. Arghami Ergonomic design of carpet weaving hand tools. International Journal of Industrial Ergonomics 37: Noweir, M. H Occupational health in developing countries with special reference to Egypt. American Journal of Industrial Medicine 9: Radjabi, A Carpets, hand-woven. In: Encyclopedia of Occupational Health and Safety, Vol. I, 3rd ed. Geneva, Switzerland: International Labor Office, pp Sobhe, K A research in international market of Iranian carpet and its export development. Iran Hand-woven Carpet Magazine 10:31 46 (in Persian).