Disabled people are those who have physical and/or mental deformities that can interrupt or obstruct them from doing activities. Liisberg [1] stated in her book that the 27 Univet Nations article fully discusses disabled people’s existence, independence, and right to work. According to International Labour Organisation (ILO), the number of people with disabilities is around one billion, or 15 percent of the world population, and 80 percent of them are in the productive age. Furthermore, in general, each country regulates the law related to the life of the community of the disabled, one of them is Indonesia. Law on Disabilities (No. 8/2016) article P11-point states that disabled people have opportunities in expanding their career and other normative rights in it. A private company should hire at least 1% and a state company should hire at least 2% of disabilities. The company that hires a disability is regulated in the Indonesian Labour Law (No. 13/2013). Article 67 section states that the entrepreneur who hires disabled people should give protection based on their disability.

There are many economic sectors with low income that become the workstation of the disabilities as the office, tailor, workshop, and wood carving. The main problem faced is the design of the workstation and equipment that is not compatible. Thus, the productivity of the disability is not optimal. Productivity will measure the efficiency of the production input, as labor and asset, used in the economy that produces a certain output level. Productivity is considered the main source of economic growth and a nation’s competitiveness. Tangen [2] stated that productivity in engineering is generally defined as the connection between output (manufactured goods) with input (consumed resources) in the transformation of the manufacturing process. The main goal of the productivity measurement is related to the technology, efficiency, real cost-saving, benchmarking of the production process, and life standard [3]. 

Workstation design is the main factor in increasing the productivity, quality and safety/health of the workers. The disabled people’s need for the workstation design is unique for each type of work. The mobility of the wheelchair becomes the main consideration in designing the workstation layout. Persechino et al. in their article discuss that the value of environmental suitability in a workstation (especially referring to an ergonomic workstation, factor typology of work risk, and work time) to accommodate individual needs in order to increase the work capability of the disabilities. Ghani et al. state that most of the disabled people especially the physical disability who have limitations in their field of study because of the incompatible work station. Therefore, designing an ergonomic wood carving workstation for disabilities is the right a decision. Ergonomics will ensure that the workers will work safely and comfortably to reach high efficiency [4]. Ergonomics can increase productivity, work quality, improve the relationship between workers, and build a better work safety culture. This need is certainly applied to the disability to work better. The design of the workstation, facilities, and infrastructure need to be adjusted to the requirements and abilities of the disabled.

Theory and Method

Workstation design: A compatible workstation design is highly important in creating an active, healthy, and efficient work environment. Furthermore, a compatible workstation design will increase work productivity. Workstation needs to follow the workflow and be able to accommodate equipment, additional equipment, tools, and material stock. Some other points to be considered are the number of people who will use the station, their physical characteristics, will they be sitting, standing, or using the two positions. Besides, the ability to reach and the communication needs of the workers need to be noticed. The air quality, temperature, and humidity should be adjusted and the wind should be avoided. The lighting should cover the needs and noise should be minimum. A good workstation needs to consider the flexibility to change it to accommodate duties, equipment, or new workers. The work surface should be height adjustable, and the chair should be adjusted to the individual needs and duties.

A poorly designed workstation is a risk factor to the operator in the production line of the assembly [6]. The workstation anthropometric design facilitates a sustainable workstation. Work standardization and Anthropometric workstation design is the strategy to increase human factor performance and productivity index in a manufacturing company. Workstation design is related to the shape, dimension, and layout (placement and orientation) of various material elements that surround one or more workers. A workstation design should consider many things such as; chairs, work surfaces, tables, equipment, tools, control system, and visual display used in work. Nature in workstations works as a work resource with a double effect which is increasing workers’ physical and psychological well-being [7]. Salvendy G. states in his book that designing workstation personal design needs some steps to be successful which are; the phase of deciding resources and high-level requirements, identification of the work system constraints and requirements, identification of the users’ needs, setting specific design goals, design of prototype(s), assessment of the prototype(s), improvements and final design.

An ergonomic layout related to the placement and orientation of each workstation in the given space (building). Ergonomic requirements are the main thing to fulfill related to the assignments done, work organization, and environmental factors. In specific, those requirements are the workstation layout by considering the process steps, developing good communication, workstation layout fit the organizational structure, layout ensuring the needed privacy, proper lighting, good air quality, assurance of safety and health, and easy access to the location. The proper workstation design can elaborate all problems to some steps that consider the ergonomic requirements. Ergonomic requirements that should be considered have been changed to workstation design guidance. Before starting the layout design, the design team collected the data related to the activities done in the designed workstation and workers’ needs. The information needed was the number of workers, organizational structure, work form, the communication between workers, safety requirements, facilities, and infrastructure.

The existence of the disabled is frequently ignored in designing a workstation. Disabilities not only change the individual’s size and shape but also their capacity in doing activities that are considered normal by the population. Workers in a wheelchair have differences in doing activities and it will face some problems related to anthropometric accuracy. A poor workstation design will aggravate the disability level. Thus, designing an environment that supports the independence of disabled people is important. Using anthropometry measurement to design an optimal environment for the disabilities mostly provide an optimal environment for all population. In designing for the disabilities (especially for those who have physical deficiencies as kyphosis, axial rotation, or difference in body parts), the use of the standard anthropometry technic and measurement is hard to be implemented because of the high statistical variable on this population. The type of disability significantly affects the body dimension distribution. A study about the anthropometry of the population of severe disabilities reports the need for at least four new linear measurement to fulfill their special need of physical problems, and five angle measurements to explain the inability of many disabled people, before drawing an assumption of the “standard” sitting posture. Thus, individual measurements should be done to those who have physical disabilities.

Disabilities Needs

This is a vicious circle: the lack of private mobility aids, the disabled couldn’t be able to escape from the poverty trap. They possibly develop secondary complications and suffer more disabilities, and become poorer. For the children, they couldn’t access the available education opportunity, and without education, they couldn’t get a job when they grow up and be pushed further in the poverty. Access to the appropriate wheelchair allows disabled people to work and to participate in the initiative of mainstream development that will decrease their poverty. As well as a wheelchair will allow a child to go to school, get an education, and get a job afterward. A wheelchair becomes the main support tool for people with physical disabilities and with mobility limitations. Hence, producing a wheelchair should notify the user’s needs and conditions. A wheelchair is a tool that provides wheeled mobility and support as a chair for those who have difficulties in walking or moving around [8].

A suitable wheelchaie is a wheelchair that fulfills the user’s needs and the environmental condition; giving the proper suitability and postural support; safe and durable; domestically available, easily obtained, preserved, and have continuous service in the country at a cheap and affordable price [9]. There’s no model or size of the single wheelchair that fits the needs of the users and the diversity of the users creates the need for wheelchair variations. They, who choose a wheelchair, consult with the users, need to understand the users’ needs and the way they operate it, and the knowledge behind the reason of the different wheelchair designs. Some important elements in measuring a wheelchair are the head position, body position, back height support, hip-width, thigh length, knees height, and leg fold. The position of the back height should be correctly measured for it will affect the length of the armrest.

International Organization for Standardization (ISO) has developed an international standard of wheelchairs which is known as ISO 7176 series [10]. This series determines the terminology and method examination to evaluate the wheelchair’s performance, size, strength, durability, and safety. The wheelchair design varies considering the different needs of the users. To ensure the compatibility of the wheelchair, the designer and the provider should completely understand the users’ environment and the needs that they meant. Users’ needs meet the best if there are many model variations to choose from. Picture 1 describes the general dimension of a wheelchair as the length, width, and height. This is used to determine the dimension of the space of the wheelchair in a vehicle, measure the handle height according to the wheelchair height, and measure the wheelchair lift dimension in the future [11].

The door for disabled people should be wide enough to allow a wheelchair entry with both hands on the wheel-rail. The width of the door as the wheelchair access should be at least 82 cm. There should be enough space to maneuver and let the users reach the doorknob and open it. The width of the corridor should be at least 92 cm considering the movement of a single wheelchair. The 

Figure 1: Dimensions of a Standard Wheelchair Uused by the Disabled [13]

wheelchair ramp couldn’t be steeper than the ratio of 1:12. The width of a ramp should be at least 92 cm (between the two handles) and a handle should be provided for a way up to more than 15 cm. The space needed to allow a wheelchair in making a 180-degree turn in a T-shaped room is 0.90 m, and for the 360-degree turn is 1.50 m x 1.50 m [12]. The height of the furniture should be 0.8 m with 0.7 m space and for the feet under the surface with 0.6 m depth.

The research strategy used in this research is quantitative research. Quantitative research is a research method that emphasizes the measurement aspects objectively to the needs of ergonomic wood carving workstation design for disabled people. This measurement can be done by describing the phenomenon of workstation design to some component points, variables, and indicators. The variable of the satisfaction level is determined and measured by processing numbers collected from the information related to the variable of satisfaction level. Referring to the numbers, a quantitative mathematic measurement technique could be done to produce a conclusion that is applied in general for the settled parameter. The object of this research is to determine the design of the wood carving workstation for the disabilities that is more comfortable and safe using the ergonomic approach, especially anthropometry.

Figure 2: The Flowchart of Research Steps In Designing Wood Carving Workstations for Disabled Workers

The research methodology design covers the working method, data collection, main and additional tools preparation, analysis, and discussion. The steps in creating the external target are divided into preliminary step, implementation, and result report. The preliminary step can be detailed as the coordination between the team and partner, the coordination between internal team and data collection training, initial survey for the need of wood carving, and worksheet preparation to collect the anthropometry data. The implementation step can be detailed as anthropometry data collection, workstation layout design, 3D model design, wood carving, spare part purchase, the installation of the ergonomic workshop, and test. The reporting step is divided into monitoring, socialization and workstation handover, training, monitoring, and evaluation.

The goal of this research is to upgrade the performance and decrease MSDs’ complaints in using the workstation for the disabilities to do wood carving. The research design used is a case study of the workers in a wood carving workstation. Moreover, the discussion method is the descriptive method that produces a systematic, factual, and accurate concept or description about the studied performance of the workstation for the disabilities. The type of data used is secondary data that covers the production step, production machine pictures, the data of production amount, normal working our for each week, and working weeks for each semester. While the primary data is in form of the time needed for the production. Picture 2 shows the steps in the research which are the survey of the wood carving workstation needs, layout design, ergonomic tool arrangement, analysis, and discussion.

Wood carving needs proper tools, skill, artistic value, and conducive working conditions to create a quality product. 

Figure 3: 3D Table Design for the Disabilities with a wheelchair

Figure 4: Proposed Production Layout and Workflow Design

According to the data SNI 12-01D79-1987 for People with Disabilities in Indonesia, the anthropometry detail are elbow height in sitting position = 22.07 cm, popliteal height = 44.77 cm, arm reach sideways = 72.75cm, arm reach forward = 74.71 cm, dan stomach thickness = 22,80 cm. The proper height of the table is matching the elbow height in the sitting position + popliteal height = 22.07 cm + 44.77 cm with a 3 cm allowance. The final table height is 69.84 cm or 70 for the round-up. The table length of the table is determined by sideways arm reach x 2 = 72.75 cm x 2 = 155 cm. Picture 3 shows the 3D cad design of the accessible table for wheelchair users.

Wood carving involves many activities as woodcutting, initial wood polishing, carving process according to the pattern, final polishing, painting, and packing. The equipment used were: chainsaw machine, drilling machine, planer machine, and painting machine. The equipment and the type of activities were used to renovate the existing layout to be a more effective and accessible layout considering the space available. Picture 3a shows the existing layout that is less organized and less ergonomic. The disabled workers should move in distance from the point of collecting the wood carving material to the workstation and from the place of the wood carving process to the painting process. The long-range distance increases the total of the working time and contributes to the disabled worker fatigue risk. Picture 4b shows the proposed layout that considers the space available, the need of the production, machine size, and accessibility. It also considers the process of wood carving and the size of the equipment. Besides, the layout was made by examining the conditions of the wheelchair movement with 82 cm width track in minimum. The fan installation was used to accelerate air circulation in the room by considering the flow of small particles from the wood process and painting process.

Gambar 4a. The existing layout of the wood carving process. b. Updated layout according to the need for equipment, activities, and accessibility.

According to several parties, the fulfillment of the disabilities needs have some impacts as one of them is an additional cost to facilitate them getting the access. Besides, a coordinative communication between the institutions in handling the disabilities. The institutions that facilitate the person’s access should develop the policy by minimizing any limitation in transportation, finance, policy, and education. This research shows that accessibility for disabled people is needed in the wood carving process. The workstation design can properly and efficiently arrange the movement for disabled workers. Besides, the layout design considers the work safety and health, as the setting of the wind direction to decrease the effect of wood chipping and painting process. The paint material mixed with the air can cause respiratory problems, irritation to the eyes, nose, and throat, dizzy or nauseous feeling, and cancer [14-16].

Disabilities can give a big impact on the economical empowerment of a country. In order to fulfill an optimum disabilities role, a technical approach is needed in performing the activities. Disabilities with a wheelchair will produce a different workstation design, as a working table with 70 cm height, 45 cm width, and 155 cm length. This research has successfully used the data of anthropometry, mechanical process, mechanical dimension, and disabilities needs in producing a safe, comfortable, and healthy layout that meets the accessibility.

Acknowledgment

Our acknowledgment goes to the Brawijaya University, the Republic of Indonesia for supporting this study. The researchers would also like to express their gratitude to the research group of Bioengineering, the laboratory of work design and ergonomics, Department of Industrial Engineering, Brawijaya University, Malang, Indonesia, for their extraordinary courage.

1. Liisberg, M.V. “Article 27 [work and employment].” The United Nations Convention on the Rights of Persons with Disabilities: A Commentary, 2017. https://doi.org/10.1 007/978-3-319-43790-3_31.

2. Tangen, S. “Demystifying productivity and performance.” International Journal of Productivity and Performance Management, 2005. https://doi.org/10.1108/174104 00510571437.

3. OECD. “Overview of productivity measures.” Measuring Productivity: OECD Manual, 2001. https://doi.org/10 .1787/9789264194519-en.

4. Sugiono, S. R.P. et al. “Improving the accessible facilities for disability at mini market KPRI, Brawijaya University.” Indonesian Journal of Disability Studies, 2018. https://doi.org/10.21776/ub.ijds.2018.005.01.10.

5. Ojo, S.O. et al. “The impact of active workstations on workplace productivity and performance: a systematic review.” International Journal of Environmental Research and Public Health, 2018. https://doi.org/10.3390/ijerp h15030417.

6. Realyvásquez-Vargas, A. et al. “Work standardization and anthropometric workstation design as an integrated approach to sustainable workplaces in the manufacturing industry.” Sustainability (Switzerland), 2020. https://doi.org/10.3390/su12093728.

7. Hui, F.K.P. and L. Aye. “Occupational stress and workplace design.” Buildings, 2018. https://doi.org/10.3390/buil dings8100133.

8. Flemmer, C.L. and R.C. Flemmer. “A review of manual wheelchairs.” Disability and Rehabilitation: Assistive Technology, 2016. https://doi.org/10.3109/17483107.2015.1099747.

9. Allen, M. et al. “Wheelchair stakeholders meeting 2018: developing a global wheelchair sector report with priority actions toward sustainable wheelchair provision.” Technology and Disability, 2019.

10. Ekiz, T., et al. “Wheelchair appropriateness in children with cerebral palsy: a single center experience.” Journal of Back and Musculoskeletal Rehabilitation, 2017. https://doi.org/10.3233/BMR-150522.

11. Sugiono, S. et al. “Upaya peningkatan utilitas bengkel disabilitas pada komponen motor roda tiga dengan e-commerce.” JPKMI (Jurnal Pengabdian Kepada Masyarakat Indonesia), 2021. https://doi.org/10.36596/jpkmi.v 2i1.108.

12. Bastedo, K. and N. Swenson. “General accessibility guidelines for online course content creation.” Universal Access Through Inclusive Instructional Design: International Perspectives on UDL, 2019. https://doi.org/ 10.4324/9780429435515-26.

13. Carrington, P. et al. “Wearables and chairables: inclusive design of mobile input and output techniques for power wheelchair users.” Proceedings of the 32nd Annual ACM Conference on Human Factors in Computing Systems (CHI ’14), 2014. https://doi.org/10.1145/2556288.2557237.

14. Amato, A. et al. “Sustainable reduction of the odor impact of painting wooden products for interior design.” Applied Sciences (Switzerland), 2020. https://doi.org/10.3390 /app10228124.

15. Rahhal, B. et al. “The impact of automobile painting profession on selected respiratory parameters: a study from Palestine.” Journal of Materials and Environmental Science, 2017.

16. Myong, J.P. et al. “Overview of occupational cancer in painters in Korea.” Annals of Occupational and Environmental Medicine, 2018. https://doi.org/10.1186/s 40557-018-0222-3.

17.