Designing workstations Work Smart - Feel Good
Introduction Despite the many laws and regulations concerning working conditions, as well as the best efforts of suppliers, many office workstations are still not ergonomically designed. This article provides a summarized manual for making your workstation more comfortable and productive, because there really is a definite relationship between comfort and productivity. Improving comfort at a workstation will result in a 10% increase in productivity (Vink and De Korte, 2008). This fact alone is reason enough to take a closer look at the design of your workstation. This document examines the eight most important aspects of your workstation while incorporating the requirements of European legislation so that you will also be complying with working conditions legislation. 1 Desk 2 Footrest 3 Seat 4 Positioning of documents Display screen Placement of display screen(s) 7 Mouse 8 Keyboard 2
1. Desk 1 EU legislation regarding desks The work desk or work surface shall have a sufficiently large, low-reflectance surface and allow a flexible arrangement of the screen, keyboard, documents and related equipment. The workstation shall be dimensioned and designed so as to provide sufficient space for the user to change position and vary movements. A work desk should be at least 80 cm (32 inches) deep and 120 cm (48 inches) wide. This work desk should be located within a space of at least four square meters (43 square feet) to give the employee enough freedom of movement. The working height of a conventional desk should be adjustable, preferably to at least between 0 and 82 cm (24 to 33 inches). For a sit-stand desk, this should be from 0 to 12 cm (24 to 0 inches) with a minimum range of 2 to 120 cm (2 to 48 inches). The height of the desk should be adjusted to elbow height or just above elbow height.a sit-stand desk is preferable to a conventional desk. A work surface measuring 0-82 cm (24-33 inches) can be used by at least 90% of its users. Sit-stand desks can contribute to a higher level of work comfort, especially with regard to relieving back complaints. The changes in working position when using a sit-stand desk as opposed to a conventional desk also appear to increase concentration that results in a 10% increase in productivity (Choi, 2010). It is important, however, that employees not stand for too long since this could lead to even more discomfort in the back and legs. As a general rule, employees should not stand any longer than they sit at a sitstand desk, and they should sit for at least 1 minutes at a time. To allow employees to really use a sit-stand desk properly, it would be advisable to have them use an easily adjustable, electrically adjustable model and for them to participate in an instructional workshop (Wilks, 200). Software programs can be effective in giving employees training in using a sit-stand desk and reminding them of when to sit and stand. One of these, the SitStandCOACH, also offers a reporting system to provide information about the use of the sit-stand desks and to adjust the baseline of sit to stand use for optimal use of these desks. 3
2. Footrest Foot support: a footrest must meet the criteria of the DIN 4 standard (support surface of at least 4x3 cm (18x14 inches), an adjustable range of at least 11 cm (4. inches), and an angle adjustable from to 1 ). 2 When a work surface is not adjustable in height (or cannot be adjusted sufficiently for the user), a footrest is sometimes required. This footrest must be at least 4 cm (18 inches) wide and 3 cm (14 inches) deep, must have an adjustable range of at least 11 cm (4. inches), and the slope of the support surface must be adjustable from at least to 1 degrees (DIN 4). For flexible workstations, it is important to provide footrests that can be adjusted quickly and easily. 4
3. Seat EU legislation regarding work chairs The work chair shall be stable and allow the operator easy freedom of movement and a comfortable position. The seat shall be adjustable in height. 3 The seat back shall be adjustable in both height and tilt. A footrest shall be made available to any one who wishes for one. The chair must at least meet the NEN-EN 133-1 standard, but preferably the NPR 1813:2009 standard as well. The backrest must be capable of tilting back by at least 1. The angle between the backrest and the seat must be less than 90 at the pelvis which is why a swiveling chair is preferable to a chair with a synchronous mechanism. The backrest of a chair with a synchronous mechanism tilts in a ratio of 1:2, 1:3 or 1:4 in relationship to the seat so that the seat will not tilt sufficiently enough in relationship to the backrest (Bos, 2003). This flexes the back to a greater extent which can result in greater discomfort in the back and legs. The angle of the backrest of a chair with a tilting mechanism can be adjusted separately from the seat to keep the angle between the seat and backrest (which is tilted slightly backward) at around 90. Synchronous mechanism the backrest tilts farther back than the seat tilts. This makes it easier for users to tip over backward and flexes the back to a greater extent. There are indications that providing ergonomic chairs that meet the previously mentioned recommendations increase working comfort (Van Niekerk, et al, 2012). However, the deciding factor in assuring increased work comfort by means of an ergonomic chair is the provision of a training session about ergonomic principles and how the chair can be adjusted (Amick, et al, 2003; Menendez, et al, 2012). Tilting or bracing mechanism the angle between the seat and backrest remains constant.
NEN-EN 133 NPR 1813A SEAT Height (cm/in) < 40-1 / 1-20. >> 12 cm ( in) adjustable 41 - (1-22) Width (cm/in) 40/1 > 40/1 > Depth (cm/in) < 40-42 / 1-17 > > cm (2 in) adjustable 38-48 / 1-19 Inclination < -2 to -7 > > tiltable -7 to +3 BACKREST Height (cm/in) 3 / 14. > 37 / 1 > Width (cm) 3 / 14. > 3-4 / 14. - 18. Lumbar support (cm/in) < 17-22 / 7-9 > 17-23 / 7-9 Inclination ARMRESTS > 1 tiltable Height (cm/in) fixed : 20-2 8-10 adjustable : < 20-2 / 8-10 > / 20-30 / 8-12 Width (cm/in) > 4 / 1. > / 2 Span (cm/in) 4-1 / 18. - 20. 3-1 / 14. - 20. Length (cm/in) > 20 / 8 > 20 / 8 Distance to rim (cm) > 10 / 4 > 20 / 8 Span (cm/in) 4-1 / 18. - 20. 3-1 / 14. - 20. Length (cm/in) > 20 / 8 > 20 / 8 Distance to rim (cm) > 10 / 4 > 20 / 8 EU legislation regarding arm support The space in front of the keyboard shall be sufficient to provide support for the hands and arms of the operator. Arm support: When working with the computer, the user s arms must be properly supported by comfortable, height-adjustable armrests, by the desk surface, or by an armrest attached to the desk surface. The arms should be supported at elbow height or a little higher and combined with a sitting position that also allows the arms to hang in a relaxed position next to the body. Effective arm support will decrease strain in the neck and shoulder region. This will result in greater work comfort, the prevention of neck and shoulder complaints, and a quicker recovery from existing complaints (Rempel, et al, 200).
4. Positioning of documents 4 EU legislation regarding document holders The document holder shall be stable and adjustable and shall be positioned so as to minimize the need for uncomfortable head and eye movements. Positioning documents: The documents must be placed in line with the keyboard, and a slightly sloping work surface should be used for reading and writing. It would be advisable to place documents between the keyboard and display screen to prevent neck rotation. A sloping work surface reduces flexion of the neck and thus increases work comfort. 7
. Display screen(s) EU legislation regarding display screens The screen must swivel and tilt easily and freely to suit the needs of the operator. It shall be possible to use a separate base for the screen or an adjustable table. The screen shall be free of reflective glare and reflections liable to cause discomfort to the user. Ideally, the display screen should measure at least 19 inches. When using more than one application at any given time, it would be advisable to work with two computer screens simultaneously, or at least with a widescreen monitor. A 19-inch screen provides greater work comfort than screens of smaller dimensions because this larger screen results in less flexion of the neck (Sommerich, et al, 2001). The resolution of a display screen indicates the number of pixels used in constructing it: the greater the resolution (number of pixels), the sharper the image. The downside to this, however, is that a screen of the same size with high resolution leads to smaller characters on the screen. The size of the pixels on the screen is also expressed in the pixel pitch which should be no smaller than 0.2 mm and preferably larger than 0.28 mm. The other most important specifications: Contrast ratio: preferably 1000 : 1; Luminescence: at least 20 cd/m2 (possibly higher in situations of greater sunlight); Color of monitor casing: light, non-reflective color (not black); Energy consumption: preferably 2 W. Dual screen? Research shows that it is possible to increase productivity by 10-1% and reduce errors by 33% with the use of two or more screens (Colvin, et al, 2004). Achieving these goals, however, also means adjusting the screens properly to limit the adverse effect of neck rotation. In using large screens, it is important to create a sufficient distance between the user and the screens. This makes flatscreen arms a practical solution. More information is available here whitepaper, Optimal performance with two or more computer screens. 8
. Placement of display screen(s) The user s distance from the screen should be at least 0 cm/24 inches (or one arm s length) but preferably farther than this. The height of the screen should be adjusted so that the viewing angle of 10-20 is below eye level. The viewing distance is determined by the character size, whereby the viewing distance should be 10 times the character size (a character size of 4 mm therefore corresponds to a viewing distance of 0 cm/24 inches). A relatively large viewing distance results in less eye strain, because the eyes do not need to accommodate as much. Moving the screen farther from the viewer, however, also means that the characters on the screen will have to be enlarged proportionally. The characters on the screen can sometimes be enlarged. Word, for example, has a zoom function that allows the characters displayed in the active document to be made larger or smaller. Larger characters are read faster than small ones. The complete display screen must be positioned in an area that is 10-20 below eye level. A monitor in this position reduces eye strain in general because it allows the eyes to accommodate and converge better. Also important: productivity is increased by around 10% at the same time (Sommerich, et al, 1998). While legislation stipulates that a screen should be adjustable to suit the needs of the user, the adjustability of a laptop screen is very limited. Adjusting the height of a laptop screen requires the use of a notebook stand. A notebook stand has a beneficial effect on neck posture and helps to increase work comfort (Boersma, 2003; Lindblad, 2003). The study of Lindblad also showed that working with a BakkerElkhuizen notebook stand and a separate mouse and keyboard increases productivity by 17% (Lindblad, 2003). To enhance work comfort even more, it would be advisable to combine a 19-inch screen with the laptop when engaging in VDU work for more than two hours a day (Sommerich, et al, 2001). 9
7. Mouse Clicking and scrolling: It is important to avoid static, unnatural bodily postures when clicking and scrolling with a mouse (extension and ulnar deviation of the wrist, pronation of the lower arm). 8 7 The mouse should be kept as close to the user s body as possible (right next to the keyboard). If entering numbers is seldom done, using a compact keyboard could be considered since this places the mouse closer to the user s body. Using a mouse results in a high level of strain, particularly on the lower arm, and, if placed far from the body, it puts additional strain on the neck and shoulder region. Using a vertical mouse that tilts the lower arm outward reduces strain on the lower arm and thus contributes to increased work comfort (Chen & Leung, 2007). Unlike other mice, the rollermouse is positioned directly in front of the user and can thus contribute to work comfort (Lin, et al, 201). Another way to reduce mouse use is simply to use more shortcut keys, but getting used to using them is usually difficult. AltMOUSE is a smart program that determines, as the user works, which operations are most often done with the mouse and then suggests shortcut keys as alternatives. Each employee is thus trained to use the shortcut keys that he/she needs to use most often. More information is available here. 10
8. Keyboard EU legislation regarding keyboards The keyboard shall be tiltable and separate from the screen so as to allow the worker to find a comfortable working position avoiding fatigue in the arms or hands. The space in front of the keyboard shall be sufficient to provide support for the hands and arms of the operator. The keyboard shall have a matt surface to avoid reflective glare. The arrangement of the keyboard and the characteristics of the keys shall be such as to facilitate the use of the keyboard. The symbols on the keys shall be adequately contrasted and legible from the design working position. A separate keyboard should be used when working on a laptop for more than two hours a day. The horizontal and vertical distances between the keys should be at least 19 mm. The user must receive clear tactile and/ or audible feedback on the keys when typing. Using a compact keyboard reduces the reaching distance to the mouse. For those who use touch typing, a split keyboard improves the position of the wrists and lower arms. The ISO 9241-410 guideline for keyboards requires that keyboards provide good tactile feedback (counterpressure) and good auditory feedback. The keys must also be at least 19 mm apart. Typing on a tablet is uncomfortable: tactile and auditory feedback is barely noticeable An example of a keyboard that does not meet these criteria is the standard keyboard on a tablet. It takes much longer to type on a tablet than on a conventional keyboard (Chaparro, 2010). A tablet provides neither of these kinds of feedback while typing. Keyboards with a tension mechanism provide better tactile and auditory feedback than keyboards with a membrane mechanism. In addition, dark characters printed on light-colored keys provide more contrast than white characters printed on black keys. This results in a higher typing speed among 80% of users. 11
Compact keyboards (keyboards without a numeric section but with a distance between the keys which is similar to a conventional keyboard) reduce the reaching distance to the mouse, reduce strain on the shoulder and lower arm, and are perceived as more comfortable than conventional keyboards (Van Lingen, 2003). A compact keyboard is a fully functional alternative to a conventional keyboard. If numerical data have to be entered frequently, a separate numeric section can be used. An ergonomically shaped keyboard, in which the keys are placed at varying heights in a gable angle, and in which the right and left sections of the keyboard are placed at a slight angle from each other, can contribute to the prevention of physical symptoms (Rempel, et al, 2009; Moore and Swanson, 2003) because this improves the position of the lower arms and wrists. Even now, the typing skills of many computer users could be improved: two in three employees do not use touch typing. The Ticken Typing Course can improve this situation since it uses an intuitive method to teach touch typing. 12
About BakkerElkhuizen Contact details: BakkerElkhuizen International B.V. Palmpolstraat 27 1327 CB ALMERE The Netherlands Tel. +31 3 4 72 E-mail: info@bakkerelkhuizen.com Website: www.bakkerelkhuizen.com BakkerElkhuizen develops excellent products for making computer use healthy and efficient. Products from BakkerElkhuizen display the perfect combination of function, ergonomics and design. BakkerElkhuizen advises and helps companies equip their workplace, including offices that use telecommuting and flexible working, so that each workstation receives the right solution and the right accessories. BakkerElkhuizen bases this on four workstation concepts: - permanent workstation - mobile workstation - flexible workstation - home workstation The point of departure is that an employee must be able to perform his or her computer work comfortably, healthily and efficiently wherever he or she works. People come first in everything that BakkerElkhuizen does, whether it concerns developing new products, performing research or cooperating with suppliers, resellers and customers. We want to share our knowledge: Subscribe here to our newsletter We would like to help you! We enjoy giving you the best possible advice, and because everyone and every organisation is unique, our specialists give tailored advice. Are you looking for a reseller of our products? Phone us (+31 3 4 72) or send us a short e-mail (info@bakkerelkhuizen.com) with your question or problem and we will contact you within 24 hours with the right advice for you. 13
References Legislation Dutch Working Conditions Decree. Date viewed: 07-10-1 http://wetten.overheid.nl/zoeken_op/regeling_ type_wetten+amvb+ministeries/titel_bevat_arbo/ datum_7-10-201/uitklappen_08/pagina_1#08 European directive for computer workstations. Date viewed: 07-10-1 Explanation of NEN and NPR norms for chairs, address only their dimensions: http://qualityoffice.nl/diensten/actief-dynamischwerken/normen-voor-bureaustoelen/ http://eur-lex.europa.eu/lexuriserv/lexuriserv. do?uri=celex:31990l0270:nl:html Workstation norms: http://www.arboportaal.nl/onderwerpen/werkplaatsnormen Chair can contribute to increased work comfort: http://www.ncbi.nlm.nih.gov/pubmed/22889123 http://www.ncbi.nlm.nih.gov/pubmed/1473374 http://www.ncbi.nlm.nih.gov/pubmed/2203009 Keyboards (Rempel) http://www.ncbi.nlm.nih.gov/pubmed/19308823 http://www.ncbi.nlm.nih.gov/pubmed/247999 14