Garments furniture design for Bangladeshi workers considering ergonomic principles

Abstract

BACKGROUND:

In Bangladesh, workers typically spend at least eight hours a day at garment factories in sitting and/or standing position. Prolonged sitting on ergonomically unfit furniture causes back, neck, and shoulder pain, which reduces the working efficiency and leading to low productivity.

OBJECTIVE:

The aim of this study is to design ergonomically correct furniture for Bangladeshi garment workers considering multivariate analysis on the anthropometric data.

METHODS:

Twelve anthropometric measures and five furniture dimensions were measured. The sample comprised of 600 volunteer workers from different garment industry. The furniture dimensions were compared with the relevant anthropometric characteristics and found a high level of mismatch (e.g. seat height (male 18%, female 94.25%), seat depth (male 96%, female 63.50%), seat width (male 9.50%, female 36.25%), sewing table height (male 56.50%, female 50%), and desk height for inspection, cutting and ironing table (male 100%, female 100%).

RESULTS:

New design specifications were proposed of the worker which improved the match percentage. The multivariate anthropometric analysis generated 8 cases and for each case the ranges of anthropometric measurements have been identified.

CONCLUSION:

The results will help to design robust ergonomic garments furniture.

Keywords

Ergonomics garments furniture anthropometry mismatch bangladeshi workers multivariate anthropometric analysis

1 Introduction

Ready-made garment industry has turned into a main pillar of the economy of Bangladesh. Recently, there are more than 5600 garment factories contributing about 76%of the country’s export earnings. Nearly 4 million workers work in those factories. Most of the factories’ working environment is unsafe and unhealthy [1]. However, workers are required to spend almost one third of the day, mostly sitting constantly in a fixed position in this unpleasant environment.

Number of researchers has conducted studies on the working environment of the garment industry and their associated problems. Keyserling et al. [2] and Serratos-Perez and Mendiola-Anda [3] found that 25%to 47.50%of the sewing machine operators are suffering cumulative trauma disorder. In addition, other researchers [4 –7] described that this disorder is more severe in the upper body part (e.g. the neck, shoulders, arms, hands, and back). Polajnar et al. [8] concluded that working postures are still a common problem in garment workers and only ergonomically designed workstations can considerably reduce the problem. Saravanan [9] identified improper sitting, incorrect position of furniture and equipment, and insufficient regular breaks as the causes of injuries and muscle pain. Muhundhan [10] explained that ergonomic design of garment workplace can minimise material handling and improve working efficiency of the worker. Chaiklieng et al. [11] studied the work-related shoulder pain and risk factors for 446 garments workers in Thailand and proposed that redesign of seats at workstations according to ergonomic guidelines should be routinely implemented. Habib [12] tried to identify the physical risk factors including musculoskeletal risk factors among sewing machine operators in a Bangladeshi garment factory. It is clear from the literatures that poorly designed workstations such as sewing tables, sitting chairs, cutting tables, inspection tables, ironing tables etc. in garment industry are responsible for developing various musculoskeletal diseases resulting the low productivity and poor quality of products. Therefore, further research is necessary for improving the sewing machine design including swivel chairs, sewing table height, and adjustable foot controls.

Historically, in 1984 a sewing machine table tilt towards the operator was designed by Finlands’ Reima clothing company [13]. The table was tested in a production line and found that it was able to reduce pain in the operator’s neck, shoulders and back. In 1988, Keyserling and Chaffin [14] developed an adjustable pneumatic chair for industrial sewing operators where the seat height and the backrest distance for the seat pan can swivel freely. After that, Delleman and Dul [15] studied the design parameters for sewing table height, table slope, and pedal positions. Kabir and Ahmed [16] explained the ergonomic design of working chairs and tables for the garment industry in Bangladesh. They provided various modifications which can reduce the stress while working. Fulder et al. [17] presented an ergonomically and economically optimal design of a workstation and explained the key dimensions of the workstation. Sarder et al. [18] evaluated the working conditions of the garment factory in south-east Asia in terms of ergonomic viewpoint. They explained that the working environment of the factory were stressful and unsafe. They suggested a low-cost solution which was successfully implemented over a period of six months and showed significant improvements of health conditions. Rempel et al. [19] worked on sewing machine operators’ chairs and concluded that the chair with the features of adjustable height and curved seat pan can significantly reduce the shoulder and neck pain. Sealetsa and Thatcher [20] described the possible ergonomic deficiencies of sewing machine operators in a textile industry in Bostana. They proposed the ergonomic design of sewing machine workstations and stated that provision of training of the ergonomics principles can improve the work-life of the operators.

Anthropometric data have been applied based on three basic principles for different dimensions such as design for i) extreme individuals, ii) adjustable range, and iii) average dimension. In the early 1960s, the adjustability was the prime focus for the design consideration; however, the large-scale production of furniture with various dimensions is based on the users’ anthropometric data [21]. Sanders and McCormick [22] reported that the design for adjustable range principle can be a suitable method for designing the height of chairs and desk based on the 5th percentile and 95th percentile of female and male participants, respectively. Khaspuri et al. [23] explained that the design for extreme individual principle can be appropriate either design for the 95th percentile male or 5th percentile female. Typically designing for the average principle is used in the case of impractical adjustability. Another widely used method for designing the workstation and workstation’s furniture is multivariate anthropometric method (MAM). Guan et al. [24] developed multivariate anthropometric model for designing the cab of US truck drivers. Gehner et al. [25] introduced a multivariate anthropometric method for crew station design.

Currently in Bangladesh, studies focussing on the consideration of the ergonomic design concept are limited [26 –30]. The traditional design of sewing tables, inspection tables and ironing tables are of low quality. This furniture are made of woods and are associated with a number of ergonomic problems. The workstation is designed without considering any anthropometric data of the worker as the carpenter has no knowledge about anthropometry [30]. Traditional sewing machines have been used in Bangladeshi garment factory where operators are required to visually control the job, orient the fabric by hand motions and control the speed of the machine by foot motions [31]. These boundaries related to body positions boost muscular-skeletal stresses if the seated posture is not accurately maintained. The physical loads initiate complications at the left shoulder, the back, the neck as well as in the lower extremities of sewing machine operators [32]. But, the configuration of workstations designed according to ergonomic considerations can decrease the number of complaints regarding musculoskeletal disorders of workers, leading to the increase in workers’ productivity, safety, physical and mental comfort [33]. Moreover, multivariate anthropometric method has not been applied yet to design the ergonomic garments furniture.

The current study focusses on the development of anthropometric data source for Bangladeshi workers from garment industry, which are important for designing an adjustable sewing chair, swing table, inspection, cutting, and ironing table at garment factory in Bangladesh. This study also shows multivariate analysis of the anthropometric parameters related to garments furniture in order to design robust ergonomic garments furniture in future. This study is believed to be a good source of information for Bangladeshi ergonomists, researchers, and manufactures about the match or mismatch of workers’ anthropometric data with the sewing chair, sewing table, inspection, cutting, and ironing table.

2 Methodology

For this study, anthropometric measurements of 600 worker of normal health (200 males and 400 females) were taken randomly with no physical disabilities from different mid-level garment factories. Workers were categorised according to their age level. This work is the extension of the authors’ previous paper [34], which was the preliminary investigation of the current work and published in a conference proceeding. The research protocol was submitted to the ethics committee of Jashore University of Sciences and Technology, Bangladesh and the committee approved the proposal with some corrections.

The dimensions of existing furniture were measured by a standard measuring instrument, while the anthropometric dimensions of the workers were measured by an anthropometer (Harpenden Anthropometer; Holtain Limited, 601) and a height measuring scale following the procedure reported in Weiner and Lourie [35], Abeysekara [36], and Pheasant [37]. The static anthropometric dimensions were measured in both standard standing and sitting positions. The workers were bare footed and wore light normal dress during the anthropometric measurement. Anthropometric dimensions were measured, when the worker seated straight on a flat surface keeping the feet (without shoes) on the floor and right angles between their lower and upper legs (knees bent at 90°). Table 1 presents the anthropometric measurements considered in this study.

Table 1
Anthropometric measurements [28]

Anthropometric measurements Explanation

Sitting height Vertical distance from a horizontal sitting surface to the highest point of the head

Sitting eye height Vertical distance from a horizontal sitting surface to the eye

Sitting shoulder height Vertical distance from a horizontal sitting surface to the top of the shoulder at the acromion

Sitting elbow height Vertical distance from a horizontal sitting surface to the tip of the elbow with flexed at 90⁰

Hip breadth Maximum horizontal distance between the hips in the sitting position

Elbow to elbow breadth Horizontal distance across the lateral surfaces of the elbows spreading sideways

Thigh clearance Vertical distance from a horizontal sitting surface to the highest point on the thigh

Knee height Vertical distance from the foot resting surface to the top of knee cap

Buttock knee length Horizontal distance from the posterior surface of the buttock to the front of the knee cap

Buttock popliteal length Horizontal distance from the posterior surface of the buttock to the popliteal surface

Popliteal height The vertical distance from the foot resting surface to the popliteal space

Stature Vertical distance from the floor to the top of the head

Anthropometric measurements	Explanation
Sitting height	Vertical distance from a horizontal sitting surface to the highest point of the head
Sitting eye height	Vertical distance from a horizontal sitting surface to the eye
Sitting shoulder height	Vertical distance from a horizontal sitting surface to the top of the shoulder at the acromion
Sitting elbow height	Vertical distance from a horizontal sitting surface to the tip of the elbow with flexed at 90⁰
Hip breadth	Maximum horizontal distance between the hips in the sitting position
Elbow to elbow breadth	Horizontal distance across the lateral surfaces of the elbows spreading sideways
Thigh clearance	Vertical distance from a horizontal sitting surface to the highest point on the thigh
Knee height	Vertical distance from the foot resting surface to the top of knee cap
Buttock knee length	Horizontal distance from the posterior surface of the buttock to the front of the knee cap
Buttock popliteal length	Horizontal distance from the posterior surface of the buttock to the popliteal surface
Popliteal height	The vertical distance from the foot resting surface to the popliteal space
Stature	Vertical distance from the floor to the top of the head

Three different types of furniture (e.g. sewing chairs, sewing tables, inspection cutting, and ironing tables) were considered in this investigation. The dimensions of sewing chairs, sewing tables, inspection cutting, and ironing tables are presented in Table 2. Anthropometric data and information obtained from the study was processed using a Microsoft Excel spread sheet and SPSS version 16.0. In this study, the maximum and minimum value, mean value, standard deviation (STD) value, 5th, 50th, and 95th percentile was estimated as a limit range. The match or mismatch was identified by comparing the anthropometric measurements of each worker with relevant existing furniture dimensions for designing the proper adjustable furniture for workers. When the anthropometric data is in the limit of criterion equation it is termed as ‘match’; anthropometric data exceed the upper limit of criterion equation called ‘high mismatch’ while below the lower limit known as ‘low mismatch’. Match/mismatch percentages were computed based on the existing furniture measurements using following combinational equations.

Table 2

Representation of garments furniture dimensions

Furniture dimension	Explanation
Chair seat height (SH)	The vertical distance from the floor to the highest point on the front of the seat
Chair seat depth (SD)	The horizontal distance from the back of the sitting surface of the seat to its front.
Chair seat width (SW)	The horizontal distance from the outer left side of the sitting surface of the seat to outer right side
Chair backrest height (BH)	The vertical distance from the top side of the seat surface to the highest point of the backrest
Table height (TH)	The vertical distance from the floor to the top of the front edge of the table.

After performing the univariate anthropometric analysis, the multivariate analysis is carried out to generate the range of anthropometric measurements for several cases to design robust ergonomic furniture. For the multivariate anthropometric analysis, this study has used principal component analysis (PCA) method to reduce the dimensional variability.

2.1 Popliteal height against seat height

Literatures suggested that, the seat height (SH) requires to be lower compared to the popliteal height (PH) so that the knees can bend enough to form an angle of 5–30° between the lower legs and the vertical axis [38, 39]. Parcells et al. defined the match between SH and PH in a condition of 0.88PH≤SH≤0.95 [40]. For the current study, a 3 cm correction factor for pedal height is included in PH because shoes are not allowed in the production floor. Therefore, the match/mismatch criterion between PH and SH is defined by Equation (1) and their relationship is shown in Fig. 1. $(PH + 3) \cos 30^{o} < SH < (PH + 3) \cos 5^{o}$ (1)

Fig. 1

Relationship between PH and SH.

2.2 Buttock popliteal length against seat depth

Numerous researchers [22 , 41–45] recommended that the seat depth (SD) needs to be designed considering the 5th percentile of buttock popliteal length (BPL) in order to support the lumbar spine by the backrest of the seat without any compression of the popliteal surface. Other researchers [46] explained that, the SD requires to be at least 5 cm less than the BPL. Parcells et al. suggested that the SD is appropriate for the users, when the SD is either ≥80%or ≤95%of the BPL [40]. Therefore, the match/mismatch criterion between SD and BPL is expressed by equation (2) and their relationship is presented in Fig. 2. $0.80 BPL \leq SD \leq 0.95 BPL$ (2)

Fig. 2

Relationship between BPL and SD.

2.3 Sitting shoulder height against backrest height

According to the findings of Evans et al. the backrest height (BH) should be below the scapula to facilitate the trunk and arms [47]. Other researchers [38, 48] suggested that the BH should be within the range between 60 and 80%of the sitting shoulder height (SSH). Hence, the match/mismatch criterion between SSH and BH is recognised by equation (3) and their relationship is presented in Fig. 3. $0.60 SSH \leq BH \leq 0.80 SSH$ (3)

Fig. 3

Relationship between SSH and BH.

2.4 Hip breadth against seat width

Researchers [22, 47] recommended that the dimension of seat width (SW) requires to be sufficiently large so that the users with the largest hip breath (HB) can sit appropriately and get enough space for lateral movements. Literatures [22 , 49–51] suggested that, the SW should be designed considering the 95th percentile of HB. Gouvali and Boudolos [38] proposed that the SW should be at least 10%larger than HB and at most 30%larger than HB. Consequently, the match/mismatch criterion between HB and SW is describe by equation (4) and their relationship is presented in Fig. 4. $1.10 HB \leq SW \leq 1.30 HB$ (4)

Fig. 4

Relationship between HB and SW.

2.5 Sitting elbow height against desk height

Parcells et al. [40] recommended that the desk height (DH) needs to be adjusted with elbow-floor height in such a way that the DH will be minimum at no bending of shoulders, while the DH will be maximum at 20° abduction and 25° flexion of shoulders (elbow rest height×0.8517 + shoulder height×0.1483). Gouvali and Boudolos [38] further modified this correlation considering elbow-floor height as the sum of seat height and elbow rest height. Accordingly, the match/mismatch criterion between SEH and DH is identified by Equation (5) and their relationship is presented in Fig. 5. $SEH \leq DH \leq SEH + 5$ (5)

Fig. 5

Relationship between SEH and TH.

3 Anthropometry-furniture dimension match/mismatch results

Table 3 shows the maximum and minimum value, mean value, standard deviation, and the 5th, 50th and 95th percentile values of thirteen anthropometric measurements. The mean height for males is 166.92 cm (STD 5.03) and for females it is 154.48 cm (STD 5.45). It is clear from the Table 3 that, all the anthropometric measurements for males are higher, when compared to those of females except for hip breath and TC.

Table 3
Anthropometric measures of workers (cm) by gender

Min. Max. Mean STD %tile 5th %tile 50th %tile 95th

Popliteal height

Male worker 39.80 48.70 44.38 1.81 41.20 45.00 46.70

Female worker 39.00 44.09 40.56 1.29 39.10 40.45 44.00

Sitting eye height

Male worker 64.80 82.70 74.09 4.76 64.60 75.30 83.50

Female Worker 62.96 71.99 69.43 2.79 66.99 69.51 71.08

Sitting height

Male worker 79.80 96.60 87.51 3.45 82.10 87.30 92.80

Female worker 70.00 86.06 79.56 3.15 74.70 80.00 84.00

Sitting elbow height

Male worker 18.90 29.30 23.09 2.66 19.70 22.90 29.00

Female worker 15.90 28.50 22.53 3.13 16.03 22.40 28.00

Thigh clearance

Male worker 10.80 18.30 16.05 1.66 13.30 16.40 18.00

Female worker 11.00 19.10 16.01 1.68 14.00 15.85 18.90

Knee height

Male worker 47.30 57.80 54.82 2.20 50.58 55.40 57.32

Female worker 44.00 54.10 49.72 2.96 44.78 50.30 53.80

Buttock knee length

Male worker 49.90 63.70 56.68 3.03 52.48 55.60 62.52

Female worker 43.00 60.60 54.89 3.19 50.50 54.95 60.10

Elbow to elbow breadth

Male worker 39.90 55.20 45.91 3.92 40.40 45.10 52.50

Female worker 34.00 50.10 42.78 3.71 36.30 43.10 50.10

Hip breadth

Male worker 28.90 39.20 34.89 2.31 30.10 34.60 39.01

Female worker 29.00 40.10 36.64 3.10 33.29 36.15 40.10

Sitting shoulder height

Male worker 44.60 66.55 56.98 4.14 55.66 57.50 64.35

Female worker 46.00 60.00 52.60 3.48 46.00 52.06 59.00

Buttock popliteal length

Male worker 36.30 47.70 41.53 2.38 38.30 41.40 47.00

Female worker 34.80 47.10 39.93 3.10 35.40 40.10 45.10

Stature

Male worker 152.00 180.20 166.92 5.03 158.80 166.55 177.70

Female worker 136.50 162.50 154.48 5.45 138.80 156.35 162.10

	Min.	Max.	Mean	STD %tile	5th %tile	50th %tile	95th
Popliteal height
Male worker	39.80	48.70	44.38	1.81	41.20	45.00	46.70
Female worker	39.00	44.09	40.56	1.29	39.10	40.45	44.00
Sitting eye height
Male worker	64.80	82.70	74.09	4.76	64.60	75.30	83.50
Female Worker	62.96	71.99	69.43	2.79	66.99	69.51	71.08
Sitting height
Male worker	79.80	96.60	87.51	3.45	82.10	87.30	92.80
Female worker	70.00	86.06	79.56	3.15	74.70	80.00	84.00
Sitting elbow height
Male worker	18.90	29.30	23.09	2.66	19.70	22.90	29.00
Female worker	15.90	28.50	22.53	3.13	16.03	22.40	28.00
Thigh clearance
Male worker	10.80	18.30	16.05	1.66	13.30	16.40	18.00
Female worker	11.00	19.10	16.01	1.68	14.00	15.85	18.90
Knee height
Male worker	47.30	57.80	54.82	2.20	50.58	55.40	57.32
Female worker	44.00	54.10	49.72	2.96	44.78	50.30	53.80
Buttock knee length
Male worker	49.90	63.70	56.68	3.03	52.48	55.60	62.52
Female worker	43.00	60.60	54.89	3.19	50.50	54.95	60.10
Elbow to elbow breadth
Male worker	39.90	55.20	45.91	3.92	40.40	45.10	52.50
Female worker	34.00	50.10	42.78	3.71	36.30	43.10	50.10
Hip breadth
Male worker	28.90	39.20	34.89	2.31	30.10	34.60	39.01
Female worker	29.00	40.10	36.64	3.10	33.29	36.15	40.10
Sitting shoulder height
Male worker	44.60	66.55	56.98	4.14	55.66	57.50	64.35
Female worker	46.00	60.00	52.60	3.48	46.00	52.06	59.00
Buttock popliteal length
Male worker	36.30	47.70	41.53	2.38	38.30	41.40	47.00
Female worker	34.80	47.10	39.93	3.10	35.40	40.10	45.10
Stature
Male worker	152.00	180.20	166.92	5.03	158.80	166.55	177.70
Female worker	136.50	162.50	154.48	5.45	138.80	156.35	162.10

Figure 6 represents existing furniture dimensions. Match/mismatch between anthropometry and furniture dimensions was identified based on the equations described earlier. Table 4 summarises the critical dimensions of existing furniture and the percentage of match/mismatch of workers’ anthropometry with the dimensions of the existing furniture. The results specify that the seat height is too high (high mismatch) for females however nearly suitable for males. The seat depth dimension is too shallow (low mismatch) for both male and female workers. The seat width and backrest height dimensions are almost appropriate for both males and females. The desk height (sewing table height) is too high (high mismatch) for both males and females. Desk height for inspection, cutting, and ironing table is not acceptable because of 100%high mismatch for both male and female workers.

Fig. 6

Representation of garments furniture measurements.

Table 4

Workers who match or mismatch existing garment furniture

Furniture type	Furniture dimensions	Dimension (cm)	Gender	Match	Low mismatch	High mismatch	Total mismatch
Sewing chair	Seat height	45	Male	164 (82%)	0	36 (18%)	36 (18%)
			Female	23 (5.75%)	0	377 (94.25%)	377 (94.25%)
	Seat depth	36	Male	8 (4%)	192 (96%)	0	192 (96%)
			Female	146 (36.50%)	254 (63.50%)	0	254 (63.50%)
	Seat width	43	Male	181 (90.50%)	13 (6.50%)	6 (3%)	19 (9.50%)
			Female	255 (63.75%	128 (32%)	17 (4.25%)	145 (36.25%)
	Back rest height	38	Male	174 (87%)	20 (10%)	6 (3%)	26 (13%)
			Female	385 (96.25%)	0	15 (3.75%)	15 (3.75%)
Sewing table	Sewing table height (desk height)	27	Male	87 (43.50%)	14 (7%)	99 (49.50%)	113 (56.50%)
			Female	200 (50%)	24 (6%)	176 (44%)	200 (50%)
Inspection, cutting, and ironing table	Desk height	46	Male	0	0	200 (100%)	200 (100%)
			Female	0	0	400 (100%)	400 (100%)

For seat height, Sanders and McCormick [22] recommended a correction factor of 3 cm (pedal height). In the case of design for adjustable range, seat height was considered as 5th and 95th percentile of the popliteal height for both female and male participants, respectively. For seat depth design, 5th percentile of female’s buttock popliteal length minus 5 cm was considered in order to support the lumbar spine by the backrest of the seat without any compression of the popliteal surface. The seat width was considered 95 percentile of female hip breath distribution which was at least 10%larger of 95 percentile (to accommodate hip breath). Researches [38, 48] suggested that the backrest needs to be lower than sitting shoulder height or between 60 to 80%of the shoulder height. Hence, BRH = 95th percentile of male workers’ sitting shoulder height×0.70 was considered in this paper for designing the ergonomically fit garment furniture. Table height was designed considering 5th percentile of female workers’ sitting elbow height and 95th percentile of male workers’ sitting elbow height [52].

With the aim of improving the dimensions of the existing sewing chairs and tables, new dimensions were proposed based on the workers’ anthropometry as shown in Table 5. The proposed furniture dimensions maximise the match percentages. The modified dimensions show the better match with the workers’ anthropometry (81.50 to 100%), when compared to the existing dimensions. The proposed desk height (sewing table height) and backrest height of chairs are suitable for most of the workers. The proposed seat depth is suitable for 92 to 93.50%of workers. The seat height and seat width are appropriate for 82.25 to 100%and 93 to 97%of workers respectively.

Table 5

Percentage of workers who match or mismatch the proposed dimensions (cm) for the design for adjustable range

Furniture type	Furniture dimensions	Dimension (cm)	Gender	Match	Low mismatch	High mismatch	Total mismatch
Sewing chair	Seat height	42–49.7	Male	100	0	0	0
			Female	82.25	0	7.75	7.75
	Seat depth	41.4	Male	92	4	4	8
			Female	93.50	0.75	5.75	6.50
	Seat width	44.11	Male	97	0	3	3
			Female	93	0	7	7
	Back rest height	38	Male	87	10	3	13
			Female	96.25	0	3.75	3.75
(Sewing inspection, cutting, and ironing table)	Desk height	58–78.7	Male	98.50	1.50	0	1.50
			Female	98	2	0	2

4 Multivariate analysis of anthropometric data

Table 6 and Table 7 show the eigenvalues, variations and coefficient matrix for male and female workers, respectively. The principal component analysis output for male and female garments workers consisted of two principal components: PC1 and PC2. The combination of these two principal components was accounted for 81.04%of the total variation in male workers and 82.74%in the female workers. The first component (PC1) predicted the overall body size. PC1 is accounted for 59.18%of the total variation for male workers and 54.98%of the total variation for female workers. Meanwhile, PC2 accounts for 21.86%of the total variation for male workers and 27.76%of the total variation for female workers, which indicates the difference between the limb length and torso height.

Table 6
Principal component analysis and variables coefficient matrix of 200 male workers

PC1 PC2 PC3 PC4 PC5

Eigenvalues 19.8857 6.07734 5.07592 3.09446 8.5866

%variance explained 59.179 21.864 9.085 5.5866 4.2857

Cumulative % 59.179 81.043 90.128 95.7146 100

Popliteal Buttock Sitting Hip Sitting

height popliteal length shoulder height breadth elbow height

Popliteal height 0.098187 –0.48188 0.25442 –0.095698 0.8272

Buttock popliteal length –0.073373 0.01789 0.16479 0.98002 0.081825

Sitting shoulder height 0.90386 –0.24089 –0.2953 0.13352 –0.14134

Hip breadth 0.2166 –0.11155 0.88862 –0.099811 –0.37555

Sitting elbow height 0.34799 0.83486 0.17685 –0.051046 0.38474

	PC1	PC2	PC3	PC4	PC5
Eigenvalues	19.8857	6.07734	5.07592	3.09446	8.5866
%variance explained	59.179	21.864	9.085	5.5866	4.2857
Cumulative %	59.179	81.043	90.128	95.7146	100
	Popliteal	Buttock	Sitting	Hip	Sitting
	height	popliteal length	shoulder height	breadth	elbow height
Popliteal height	0.098187	–0.48188	0.25442	–0.095698	0.8272
Buttock popliteal length	–0.073373	0.01789	0.16479	0.98002	0.081825
Sitting shoulder height	0.90386	–0.24089	–0.2953	0.13352	–0.14134
Hip breadth	0.2166	–0.11155	0.88862	–0.099811	–0.37555
Sitting elbow height	0.34799	0.83486	0.17685	–0.051046	0.38474

Table 7

Principal component analysis and variables coefficient matrix for 400 female workers

	PC1	PC2	PC3	PC4	PC5
Eigenvalues	15.6392	9.65198	6.32507	1.61648	1.53639
%variance explained	54.98	27.76	8.192	4.6492	4.4188
Cumulative %	54.98	82.74	90.932	95.5812	100
	Popliteal	Buttock	Sitting	Hip	Sitting
	height	popliteal length	shoulder height	breadth	elbow height
Popliteal height	–0.07767	–0.018634	0.033664	–0.55293	0.82871
Buttock popliteal length	–0.24544	0.93289	0.2624	0.024447	0.0036251
Sitting shoulder height	0.59051	–0.070856	0.80356	0.0037524	0.023612
Hip breadth	0.76432	0.35259	–0.53155	–0.082613	0.046036
Sitting elbow height	0.028937	–0.0044831	–0.041905	0.82876	0.55727

Figures 7 8 show the plots of the first two principal components for the male workers. The ellipse in Fig. 7 bounds 90%of the male workers, while the ellipse in Fig. 8 bounds 95%of the male workers. In the both cases, four severe cases (points A–D) were chosen at the intersection of the ellipse with the PC1 and PC2 axes, whereas another four severe cases (points W–Z) were chosen at the mid-points between the PC1 and PC2 axes. In order to produce the body segment design values, the PCA values of each of the cases for male workers have been converted to the original variable space. Table 8 represents the boundary cases of the anthropometric limits for male workers for 95 and 90%accommodation.

Fig. 7

Scatter plot of male cases for the first two principal components (PC1 and PC2). Also plotted is an ellipse enclosing 95%of cases, along with eight boundary cases (A–D, W–Z).

Fig. 8

Scatter plot of male cases for the first two principal components (PC1 and PC2). Also plotted is an ellipse enclosing 90%of cases, along with eight boundary cases (A–D, W–Z).

Table 8

Boundary cases anthropometric limits for 95%and 90%accommodation for male workers (n = 200)

Measurements		95%accommodation
	Case A	Case B	Case C	Case D	Case W	Case X	Case Y	Case Z
Popliteal height	40.9	47.8	47.9	40.8	^*39.5	47.8	^**48.1	40.8
Buttock popliteal height	38.4	46.5	46.2	38.5	38.7	^**47.3	46.6	^*38.1
Sitting shoulder height	46.7	62.9	64.0	47.7	^*46.1	64.1	^**65.7	45.7
Hip breadth	31.9	38.3	38.7	31.0	31.7	^**39.0	38.1	^*30.2
Sitting elbow height	20.8	28.8	28.7	21.6	21.1	^**28.9	28.1	^*20.4
	90%accommodation
Popliteal height	42.6	47.2	47.1	41.3	^*41.2	47.1	^**47.3	42.4
Buttock popliteal length	37.7	46.2	46.1	38.1	38.4	^**46.3	46.2	^*37.4
Sitting shoulder height	46.3	62.3	63.1	47.4	^*45.1	61.1	^**64.7	46.7
Hip breadth	31.5	36.5	37.1	30.3	30.7	^**37.8	36.3	^*29.9
Sitting elbow height	21.3	26.8	27.2	21.2	20.6	^**27.3	27.1	^*20.1

^* = Minimum value; ^** = maximum value; all values are in mm.

Figures 9 10 show the plots of PC1 and PC2 for the female workers in which the ellipses enclose 90%and 95%of the female subjects, respectively. Similar to the male subjects, four severe cases (points A–D) were chosen at the intersection of the ellipse with the PC1 and PC2 axes, whereas another four severe cases (points W–Z) were chosen at the mid-points between the PC1 and PC2 axes. Table 9 represent the boundary cases of the anthropometric limits of 95 and 90%accommodation for female workers.

Fig. 9

Scatter plot of female cases for the first two principal components (PC1 and PC2). Also plotted is an ellipse enclosing 95%of cases, along with eight boundary cases (A–D, W–Z).

Fig. 10

Scatter plot of male cases for the first two principal components (PC1 and PC2). Also plotted is an ellipse enclosing 95%of cases, along with eight boundary cases (A–D, W–Z).

Table 9

Boundary cases anthropometric limits for 95%and 90%accommodation for female workers (n = 400)

Measurements		95%accommodation
	Case A	Case B	Case C	Case D	Case W	Case X	Case Y	Case Z
Popliteal height	40.6	43.5	43.4	40.8	^*40.2	42.9	^**43.9	40.9
Buttock popliteal height	35.3	46.8	46.1	35.4	35.4	^**46.9	46.2	^*35.0
Sitting shoulder height	46.9	58.8	58.7	47.1	^*46.2	59.2	^**59.6	46.9
Hip breadth	30.3	38.7	38.6	31.1	30.6	^**39.3	38.2	^*29.3
Sitting elbow height	16.3	27.4	27.8	17.3	17.5	^**28.1	27.9	^*16.0
	90%accommodation
Popliteal height	40.3	42.2	42.3	40.4	^*40.1	42.1	^**43.3	40.4
Buttock popliteal length	36.2	46.4	45.3	35.4	36.7	^**46.3	45.6	^*35.2
Sitting shoulder height	47.9	58.4	58.3	47.7	^*47.1	58.1	^**58.7	47.9
Hip breadth	31.2	37.5	38.2	31.6	31.7	^**38.3	37.4	^*30.9
Sitting elbow height	17.4	25.4	25.8	18.2	18.7	^**26.6	25.3	^*17.2

^* = Minimum value; ^** = maximum value; all values are in mm.

5 Discussion

The results of the current study demonstrate a significant mismatch between the anthropometric dimensions of the garment workers and the dimensions of the existing furniture. It indicates that, the workers are unable to reach the foot pedal because of the wrong seat height dimensions. This may cause an increase in tissue pressure on the posterior portion of the thigh. The mismatch percentages of seat depth are too high. Therefore, the workers have to push forward their buttock to the front edge of the seat during the sewing operations as shown in Fig. 11(A).

Fig. 11

Working positions at existing sewing workstations.

When there is no enough back support, it leads to the slumped and kyphotic posture. Bendix et al. [53] recommended that, a good back rest makes the spine steady, fits the natural spinal curves, reduces the kyphotic posture, and facilitates the lumbar lordosis. The low mismatch of seat width (32%) for female indicates that, the chairs are narrow for the female workers. Therefore, the workers with large hip breadth cannot get enough space to sit properly. Researchers [22 , 47] have pointed out that, the narrow seats can cause discomfort, untidiness, and mobility constraints, whereas the wider seats mostly influence the aesthetics and space economy [38]. The seat height for females is considered about 42 cm which might be a good design choice and this dimension is within the ANSI recommendation (40.6 to 52 cm) [16]. This proposed dimension increases the match percentage from 5.75 to 82.25%. Chairs with deep seats exceed the workers’ buttock popliteal length and as a result the back rest cannot be used properly. The back-rest height of 38 cm for male worker may be a proper design. The seat depth should be set in such a way that it can accommodate the workers with larger hip breath. The seat depth of 42 cm is considered for chair design. This value increases the match percentage from 8 to 92%for male and from 36.50 to 93.5%for female worker.

The existing backrest height dimension (38 cm) of the garment’s furniture was appropriate for the workers. The results suggested that, the backrest height was suitable for at least 87%of the male and 96.25%of the female workers. In order to define the seat back rest height, three parameters (seat back angle, seat back width, seat back height) are necessary. The ANSI recommendations suggest a minimum range of the seat back angle to be between 90° and 105° with the seat pan to be with at least 30.50 cm width of the seat back in the lumbar region. Lueder [54] recommended that, the seat back height should be a minimum of 50 cm. However, in garment industries workers usually work in a forward tilted position. This means that a 90° seat back angle is suitable for garments workers. The mismatch percentage for the case of sewing table height (desk height) is too high for 100%(high mismatch) of the workers (both females and male). Therefore, the height of the sewing table exceeds the workers’ elbow rest height; hence, the workers need to create force for lifting their arms during the sewing operations as indicated in Fig. 11 (B). This may cause discomfort to the worker, more muscular load, and shoulder pain or requires bending the trunk forward leading to the increase in the spinal load. The common sewing table height (desk height) should be 69 cm (26 + 43 = 69) for male and 68 cm (26 + 42) for female which is within the limits of the ANSI recommendations (minimum 66.50 cm). However, the adjustable range 58–78.70 cm can also be suitable for the worker having dimension below ANSI recommendations. This also increases the match percentage from 0 to 98.50%for male and from 0 to 98%for female worker. In this survey, it is found that almost all the inspection, cutting, and ironing workers are required to perform their work in a standing position for long periods of time. Therefore, in this study appropriate working table heights (for inspection, cutting, and ironing) is recommended for workers. From this study 26 cm is recommended to be the right design height. The improved furniture design should be appropriate for almost workers.

6 Limitations

The purpose of this work is to develop anthropometric databank of Bangladeshi garment workers as well as to formulate anthropometric design guideline of garment furniture. The study also performs a multivariate anthropometric analysis. Bangladesh has large population size. Therefore, it is very difficult to establish strong relationship based on the small sample size. In this study, 200 male and 400 female workers are taken as the representative of the entire garment workers. However, incorporation of large sample size can develop more accurate and precise relationship between workers’ anthropometry and garment furniture dimensions.

7 Conclusions

The aim of the current study was to raise ergonomic consciousness in the Bangladeshi garments industry. The study shows that there exists a substantial mismatches between the dimensions of the existing garment furniture and anthropometric dimensions of garment workers. A higher level of mismatch was observed in the case of seat depth, seat height, and sewing table height. It is clear from the estimation of mismatch that, the existing garment furniture are not ergonomically appropriate and comfortable to use for Bangladeshi workers, which is responsible for a number of health problems of workers. The seat height and table height is too high for the majority of the garment workers, while the seat depth is too large and seat width is too narrow for female workers. The reason behind this is the design of garment furniture without considering the workers’ anthropometry. Based on these findings the authors’ conclusion is that there are significant problems in this industry interfering with the health, well-being, and productivity of workers. The new proposed dimensions for garments workers will help to avoid unwanted anxiety upon them and improve their working efficiency. However, this study has identified 8 cases through a multivariate anthropometric analysis. Robust ergonomic garment furniture can be designed by considering the anthropometric measurements for these 8 cases separately.

Footnotes

Acknowledgments

The authors are grateful for the Ethics Committee (Research) of Jashore University of Science and Technology (JUST), Bangladesh for their final kind approval on the research protocol. The authors are also thankful to the factory administrations and staff members for providing their supports for conducting the survey in their premises. The authors greatly appreciate the constructive comments from anonymous referees that helped improve the quality of the manuscript.

Conflict of interest

None to report.

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