Redesigning Ergonomic Vertical Folding Desk in an Apartment Room using Anthropometric Approach

The use of a desk is generally big and can only be used for learning and does not have any additional functions; it causes the table to consume a lot of space in a room. The occupancy of the vertical occupancy is minimal, given the nu-merous availability. This design hopes to meet the needs of users who live in a place with narrow areas such as apartments, boards, houses, and other living rooms to do some activities related to the function of furniture that will be designed. With the increasing interest of people living in apartments, it is essential to consider furniture that will be used in a relatively narrow room. Thus, it is needed to overcome the conditions of the confined room. This research aims at redesigning an ergonomic and innovative folding desk in the apartment room, to provide comfort in its users. In improving the folding desk, it is hoped that this proposed folding desk will be more ergonomic and can be used daily. The results show that the recommended size for the ergonomic desk is 62 cm wide, 163 cm long, and 29 cm high; also, the recommended size of the seat is 50 cm high.


Introduction
A desk is an essential means of support in the process of human activities (Kristanto & Saputra, 2011). The use of desks are generally big and can only be used for learning and do not have other additional functions. Hence, it spends much space in a room, whereas the wide occupancy in vertical residences is very limited to consider its furniture. This design is expected to meet the needs of users who live in residential areas with a narrow or limited area such as apartments, boarding houses, flats, and other habitable spaces to perform several activities related to the function of furniture to be designed (Raymondus, 2013).
The apartment itself has ten characteristics explained by Harianto (2014). Those characteristics are built in more than two floors and are usually a vertical building, consists of some units on one floor, flexible in achieving maximum utilization of space, efficient and effective also ecofriendly, has shared facilities that are not necessarily owned by housing, generally, there are commercial areas in the apartment building or environment, vertical circulation in the form of stairs or lifts and horizontal circulation, security, peace, and privacy are guaranteed, easy and fast access to reach existing facilities; also structures and building materials can last for a long time.
Look at to its function there are three functions of apartment, those are primary functions, as a living place, secondary function which is added in an apartment to give comfort towards its primary function, and complementary function which supports the primary and secondary functions (Eka, et al., 2016). Besides, there are four types based on the apartment unit. Those are studio, a family apartment consisting of one, two, or three rooms, loft, and penthouse (Cahyaningtyas & Rahardjo, 2016). Based on its building mass shape, an apartment can be classified into two categories; those are slab apartment and tower apartment (Utami, et al., 2015).
In conducting this study, the researchers use an anthropometry approach to redesign the folding desk used in the apartment. Harrianto (2010) confirms that anthropometry is the measurements of the human body naturally both in carrying out static activities (actual size) and dynamic (adjusted to work). Anthropometry data preparation needs to pay attention to variability because several factors affect the size of the human body (Jennie, et al., 2017). Herawati & Pawitra explains (2013) anthropometric data, which is used as a basis for product design are generally grouped into two types, namely static anthropometry (structural) and dynamic anthropometry (functional).
The application of anthropometric data can be made if the average standard (mean) and standard deviation (SD) are available from a normal distribution (Nurrohman & Yohanes, 2017). There are three principles in the use of those terms, namely the design of facilities based on extreme individuals, the design of facilities that can be adjusted, and the design of facilities based on the average size of the user (Pranindo & Nurkertamanda, 2013).
The design of work equipment based on anthropometric data of the user aims to reduce the level of work fatigue, improve work performance and minimize the potential for work accidents (Jennie, et al., 2017). The product design itself is divided into seven steps that each have their method. The seven steps are purpose classification, function determination, needs arrangement, characteristics determination, improvement details, alternative construction, and alternative evaluation (Priyatna & Wiyancoko, 2014). Furthermore, product development is a series of activities that begin with the analysis of perceptions and opportunities, then end with the stages of production, sales, and delivery (Ulrich & Epinger, 2001).
Based on the condition mentioned above, the researcher tries to redesign an ergonomic folding desk to fit in the limited space in the apartment. The ergonomics discipline, in particular, will learn the limitations of the human ability to interact with technology and homemade products (Raymondus, 2013). There are four main objectives of ergonomics, namely maximizing employee efficiency, improving work health and safety, encouraging work safely, comfortable and vibrant, and maximizing work form.
It is also essential to have data homogeneity since it cannot be inserted in the next calculation if the data are not equal. Hence, the data should be tested to meet the requirement. The data also should be adequate to be calculated to avoid data retake. If N' < N so that the data are considered adequate to be measured. On the other hand, if N' > N so that the data are less adequate to be calculated. Meaning that the data retake necessary to do. To distribute the data, it needs a normal distribution with the formula of the bell-shaped symmetric towards x = μ. This normal distribution or normal curve is also called Gauss distribution with the following formula, where:

Research Method
This study was conducted at Menara Rungkut City Surabaya in January 2019 until the required data was sufficient. The variables in this study are folding desk as a bound variable and anthropometric data, desk design, and questionnaire as an independent variable. The researchers also used a questionnaire to provide easiness to respondents in giving opinions and answering questions since it is provided with some options to be chosen (Bimo, 2010). Problem-solving steps that can be taken in this study to get the results or solutions from the research to be carried out from beginning to end.

Initial Desk Design
The initial table design in Menara Rungkut apartment can be seen in the following picture: Figure 1. Initial desk design In the figure displayed above, the desk height 50 cm high, the desk width is 40 cm wide, and the desk length is 60 cm long.

Proposed desk design Data homogeneity test
Based on the chart of data homogeneity test of the apartment users, the results shown in the following table: The value of k = 2 and the value of s = 0 , 05 If N '≤ N then the data is adequate to do the design If N '≥ N then the data is not enough to do the design The data from the measurement result is sufficient to design the product. The following table is the result of the data adequacy test.

Determining the Percentile
Here the researchers determined the size desk by adjusting the percentile.  Determine the width of the table HR of the desk = ̅ -5 (SD) = 72,87 -1,645(6,6) = 62 cm The width of the recommended desk is 62 cm wide  Determine the length of the table HS of the desk = ̅ -5 (SD) = 184,72 -1,654(12,81) = 163 cm The length of the recommended desk is 163 cm long  Determine the height of the table EH of the desk = ̅ + Tolerance = 24,17 + 5 = 29 cm The height of the recommended desk is 39.07 cm high

Planning the design of recommended folding desk
The proposed folding desk for users at age 19-40 years was 62 cm wide for the desk width, 163 cm long for the desk length, 29 cm high for the desk height, and 50 cm high for recommended seat height. The table above is the result of the questionnaire, which is responded by forty occupants living in Menara Rungkut Apartment, Surabaya. By applying the analysis of the data analysis, the proposed folding desk can be seen in the following figure: Figure 2. The proposed folding desk design in the apartment Compare to the initial desk design, the proposed folding desk design is much more appropriate for people living in the apartment since the size is adequate, safe, and healthy to its users. The comparison between the initial design and proposed design is shown in the following table:

Conclusion
The results showed that an ergonomic folding desk design is the design that has 62 cm wide, 163 cm long, and 29 cm high. Besides that, the seat height should have 50 cm high. Besides, this desk has several storage functions under the desk pad that are used to store books, stationery, dining places, luggage, and other equipment that support learning activities at school, as well as the legs that can be folded when not in use. Thus, its wide use needs to be considered.