Ergonomics ID1-DT1-EA The module details the basic terminology and principles of anthropometrics and ergonomics in terms of their relationship to human proportions and environment. Through the study of the module, the student will be able to assess furniture and other items in the built environment and its ultimate definition based on human measurements and scale. The aim of the module is to establish this relationship and to provide background information on its history and use. The outcomes are to familiarize the student with common points of measurement on the human body and to offer practical knowledge and provide reference for the future designing of interior elements. The ability to comprehend the connection between human measurements and building form. The critical analysis of space in order to be more appropriate and efficient for human use. Basic understanding of principles and application in history as a means to create more efficient objects. The ability to use human scale and proportions as a reference and starting point for design work Developing a habit of using measurement as a basis for work 1. Evaluate and review the average dimensions used as a standard of measure of interior spaces and objects. 2. Assess your individual dimensions and measurements as a means of seeing the variances in measurements to be taken into account when designing. 3. Completion of assignment ID1-BT1-EA-B1 using standard measurements and relevant body dimensions. Tutorial Notes for Module ID1-BT1-EA.
*ANTHROPOMETRICS* (DEFINITION) The definition of the term, anthropometrics, is derived from the Greek components of the word: anthro, pertaining to the body and metric indicating measure. The science itself uses data and information on human dimensions and ranges of motion and applies this information to designed objects. This concept is by no means isolated to current times, but instead has provided fascination to many, as in the case of Vitruvius Pollio, as early back as 1st Century BC, Rome. (Fig.01) (HISTORY) We may associate Vitruvius with his iconic representation of man being the measure of all things, realised in the drawings of Leonardo Da Vinci. The circle and square depicted are representative of the body s basic tendency toward geometry and precision of measurement. (Fig.02) One is able to appreciate the proportions of the human body and its application in the determining of basic measures of building and function, whereby body parts are scrutinized, measured, averaged and idealised to assess their application with the built environment. Various systems and units of measurement are derived and named after the units of body measurement of which they were originally conceived. Some of these basic rules / measures are listed below: a palm is the width of four fingers a foot is the width of four palms (i.e. 12 inches) a cubit is the width of six palms a pace is four cubits a man's height is four cubits (and thus 24 palms) the length of a man's outspread arms (arm span) is equal to his height the distance from the hairline to the bottom of the chin is one-tenth of a man's height the distance from the top of the head to the bottom of the chin is one-eighth of a man's height the distance from the bottom of the neck to the hairline is one-sixth of a man's height the maximum width of the shoulders is a quarter of a man's height the distance from the middle of the chest to the top of the head is a quarter of a man's height the distance from the elbow to the tip of the hand is a quarter of a man's height the distance from the elbow to the armpit is one-eighth of a man's height the length of the hand is one-tenth of a man's height the distance from the bottom of the chin to the nose is one-third of the length of the head the distance from the hairline to the eyebrows is one-third of the length of the face the length of the ear is one-third of the length of the face the length of a man's foot is one-sixth of his height Fig 1. Leonardo da Vinci: Available at www.alviarmanihairtransplant.com. (accessed on 24/11/2010) Fig 2. Leonardo da Vinci, Vitruvian Man: Available at http://www.design21sdn.com/people/23759/posts/5867
The precision and emphasis on proportion evident in Da Vinci s illustration is directly related to an extract in Vitruvius De architectura, which states: "For the human body is so designed by nature that the face, from the chin to the top of the forehead and the lowest roots of the hair, is a tenth part of the whole height; the open hand from the wrist to the tip of the middle finger is just the same; the head from the chin to the crown is an eighth, and with the neck and shoulder from the top of the breast to the lowest roots of the hair is a sixth; from the middle of the breast to the summit of the crown is a fourth. If we take the height of the face itself, the distance from the bottom of the chin to the underside of the nostrils is one third of it; the nose from the underside of the nostrils to a line between the eyebrows is the same; from there to the lowest roots of the hair is also a third, comprising the forehead. The length of the foot is one sixth of the height of the body; of the forearm, one fourth; and the breadth of the breast is also one fourth. The other members, too, have their own symmetrical proportions, and it was by employing them that the famous painters and sculptors of antiquity attained to great and endless renown. Similarly, in the members of a temple there ought to be the greatest harmony in the symmetrical relations of the different parts to the general magnitude of the whole. Then again, in the human body the central point is naturally the navel. For if a man be placed flat on his back, with his hands and feet extended, and a pair of compasses centred at his navel, the fingers and toes of his two hands and feet will touch the circumference of a circle described therefrom. And just as the human body yields a circular outline, so too a square figure may be found from it. For if we measure the distance from the soles of the feet to the top of the head, and then apply that measure to the outstretched arms, the breadth will be found to be the same as the height, as in the case of plane surfaces which are perfectly square." We, as designers, may be more familiar with the architect, Le Corbusier, and his interpretation of Vitruvius principles in his creation on Modular No.1. This model of man and average dimensions was used to formulate the proportions and use of space within his architectural forms, in an ultimate expression of the relation and functionality of man and building. (For extra reading / research: examples such as Unite D Habitation) (see Figure 3 & 4) The relevance of anthropometrics in the sphere of design of product and space is the use of the data about body dimensions to make the objects and spaces we interact with more considerate of the human form, and thus more efficient. Anthropometrics relies on the consideration of averages or standards of proportions, a topic that was explored extensively by Euclid and his theory on the Golden Section. In this theory of divine proportion the principle states that the third term of the proportion, is equal to the sum of the other two components of the proportion. One illustration of this in application to design and the human body is the concept that dividing the body with an imaginary line across the navel, and the 3 measurements that result, will allow for a near perfect Golden Section ratio. This means that the ratio of the total height to the distance of the navel from the floor results in the irrational mathematical constant that is the Golden Section / ratio. (see Figure 5) Vitruvius Pollio. Available at http://www.perseus.tufts.edu. Accessed on 24 /11/2010 Fig 3. Available at www.paul-rand.com. Accessed on 01/12/2010 Fig 4. Available at www.adrianainfirenzeblogspot.com. Accessed on 01/12/2010
(ADAPTATIONS) Obviously, as societies and subsequent ways of living adapt and change, the parameters and averages will also shift to accommodate. Culture, lifestyle and nutrition will cause deviations in these averages, as well as the human tendency to suffer some degree of physical limitation (whether temporary or permanent) - a factor that needs to be accommodated accordingly. Much research has been done on the dimensional requirements of those that require the use of a wheelchair, or are elderly. Spaces such as hospitals and other public areas will need to be able to cater for these dimensional requirements and thus work beyond the standard human measure to determine its functionality. In this instance one must include the wheelchair as an extension of the body s basic dimensions and determine a new set of averages. (see Fig 6, 7 & 8) (APPLICATION IN INTERIOR DESIGN) The diagrams to follow detail the dimensions pertaining to the body that are more commonly used by interior designers. These measurements are used to determine the basic sizes of the objects with which we interact as well as the spaces between objects and their functional extents. These in turn are reflected in building regulation standards and product design. (see Fig 9) (UNREALISTIC STANDARDS) Below is an extract from an internet article outlining unrealistic body standards and how that might be reflected in the design of a product, based on a new average of anthropometric data. "Fashion designers work to a fantasy of what the human body looks like. They are taught how to draw human figures in a distorted, idealised way. The two figures in the middle are typical of fashion design drawings. Designs are based on these oddly proportioned, fantasy, body shapes. (see Fig10) The figures on either side were statistical averages from a series of anthropometrics studies done with US military personnel. Whilst limited to a select age range and profession, these nonetheless are based on measurable and observable reality. These are real body shapes. (From Human Dimension & Interior Space by Julius Panero and Martin Zelnilk) (see Fig 10) If a product designer were to work off the same fantasy body shapes that fashion designers so, a typical toilet would look like this. (see Fig 11) None of us would willingly climb a stepladder every time we need to use our toilet how silly would that be? And yet, why is it that we continue to try and fit into clothes that were not designed for our bodies to begin with, or shoes that are uncomfortable and damage our feet? This is most peculiar." Fig 09. Available at www.k-state.edu/udlearnsib/lesson4. Accessed on 01/12/2010 Liew, Zern. 17 January 2008. Available at www.eicolab.com.au. Accessed on 01/12/2010
ERGONOMICS (DEFINITION) The term ergonomics is derived from the Greek word ergon, meaning work and nomos (laws). In essence it is the study of how human and environment fit together and how these aspects are designed in such a way so as to maximize efficiency, both in use and production. This extends not only to the workplace but also the components such as equipment, systems, services and indeed the job itself. The use of products which are badly designed in an ergonomic sense increases the risk of long term disabilities resulting from injuries from repetitive strain on the body. Interaction with objects highlight their shortcomings almost immediately, as the human body has a tendency to feel awkward and uncomfortable when interacting with objects which do not suit their shape and function. The term ergonomically-designed would thus imply that the product has taken into account this user-product interface and heeds the user s body or actions. (see Figure 12) It is a science often described as the "science of everyday life and integrates the basic human sciences of anatomy, physiology and psychology. Its objectives are ultimately that of increased production through human capabilities as well as maintaining human well-being. (HISTORY) As the origin of its name might reveal, Ergonomics can be traced to the culture of Ancient Greece where the basic principles were used in the design of tools, jobs and workplaces. Hippocrates was said to have provided specific descriptions for the design and layout of a surgeon s workplace (to the extent of the arrangement of tools). Even the Egyptians integrated some ergonomic principles into the design of their tools, considering the user in their interface with components. Within a more modern context, Wojciech Jastrzebowski, a Polish educator and scientist, was said to have first used the term ergonomics, relative to the science of labour. This was further explored by Frederick Winslow Taylor in the latter part of the 19th Century in an effort to make labour processes more efficient and productive. As tools and machinery became more developed, so was the effort to maximize the potential for man to interact with it in an increasingly streamlined manner. The intricacies of war demanded a more complex glance at ergonomics, and with the development of new complex machines and weaponry came the need for better interaction of the human with these products. A more defined look at ergonomics within cockpit design looking into the placement of buttons relative to the human body and its dimensions reduced the human error factor and potential crashes. Here highlights the strong link between ergonomic consideration and safety - where the more a designed object is mindful and embracing of the human form, the less potential for injury as a result of this lack of human reference. Fig 12. Available at www.shoponline2011.com. Accessed on 01/12/2010
The Space Age brought up new questions of how the human body would interact with a weightless environment and g-force pressure. Similarly, the Information Age and its gadgets would yield further investigations, as well as the specific field of human-computer-interaction (HCI). Aside from HCI, designers can explore the ideas of ergonomics in various aspects of the design of the space. One such example of the relevance of ergonomics to contemporary interior designers is in the design of kitchens, where anthropometric and ergonomic data is essential for the efficiency and usability of this area (see Fig 13). In contemporary times, ergonomics is sometimes referred to as human engineering. (SIGNIFICANCE OF ERGONOMICS) As the principles of ergonomics are applied to a variety of elements of everyday life (from seats to kitchen implements), one could assume that many different occupations might contribute to their design. These could include human factors/ergonomics specialists; safety engineers; industrial hygienists, engineers, designers; human resource managers; occupational medicine physicians and therapists; and chiropractors. Knowledge of the principles which ultimate govern the use of our workspaces and objects is an important thing to consider for both workers and employers both in terms of safety and efficiency. As technology develops, so too must our approach to design and the concept of the workplace environment. Heeding ergonomics helps to reduce injuries and illnesses in the workplace. This in turn contributes to a reduction in workers compensation costs, medical claims and time away from work. (ERGONOMIC CONSIDERATIONS) Since the idea of anthropometrics and ergonomics takes into account an average dimension for the human body components (see Fig 14), one must assume that adjustability of physical elements is an important consideration in design. The varying sizes of individuals will highlight the problem of a typical workstation to be applied to all users. The ability to make an adjustment (eg in chair height) can reduce discomfort and ultimately fatigue. Work surfaces need to be at an appropriate height relative to chairs or standing positions and items need to be placed and arranged in an efficient flow for work. (see Fig 15) (ERGONOMICS & THE BODY) Where the design of an object or workplace is out of sync with the physical body, particularly with regard to work surfaces, musculoskeletal disorders can result. Poor posture is often adapted when working, often due to an unsuitability of workspace. Sitting in positions where the natural curve of the spine is not maintained can have a devastating effect on the health of the body for a large part, the health of our body is directly related to the health of the spinal system. Repeating this motion and interaction with objects can lead to repetitive strain injuries, particularly if applied with a great amount of force. Fig 13. Available at www.valcucine.com. Accessed on 01/12/2010 Fig 15. Available from www.ergonomics-ohs.com.au. Accessed on 01/12/2010
Disorders such as carpal-tunnel syndrome, where the nerves of the wrists are affected, can have permanentlydisabling effects. This condition affects computer users, whose interaction with this form of technology makes them especially vulnerable. Repeated exposure to the computer also has a marked affect on vision. When seated, the following positions and angles should be maintained for optimum health: Feet should rest on the floor, with legs and body forming 90 to 110 angles. The body should be straight, with the neck upright and supporting the head balanced on the spine (not forward or twisted to the sides). Upper arms should be perpendicular to the floor; forearms should be parallel to the floor. (Fig 15) (MAIN ASPECTS OF STUDY IN ERGONOMICS) PHYSICAL ASPECTS OF THE USER-MACHINE INTERFACE o This aspect deals with the size, shape, colour, texture and method of operation of displays and controls for cars, domestic appliances, industrial and commercial equipment. The aesthetic form of the object is strongly related to the functional interaction, but is also equally considered in its value as a means of design development. COGNITIVE ASPECTS OF THE USER-MACHINE INTERFACE o These aspects involve the understanding of instructions and other information. It could deal with the style of dialogue between machine and user and how effective it is in communicating understanding. WORKPLACE DESIGN & WORKSPACE LAYOUT o This could be attributed to the layout of offices, factories, domestic kitchens, public spaces for ultimate efficiency. o It involves the detailed relationships between furniture and equipment, as well as between different equipment components PHYSICAL ENVIRONMENT o This aspect measures the effects of climate, noise and vibration, illumination and chemical / biological contaminants on human performance & health. PSYCHOLOGICAL ENVIRONMENT o Organisational structure within a group and its effects on satisfaction with the task, productivity and group membership are assessed in order to describe the psychological aspects that ultimately contribute to efficiency. JOB DESIGN, SELECTION & TRAINING o This aspect could include: the effects of shift work on performance; design of instructions, job aids and training schemes; selection of personnel against criteria of aptitude & personality. Fig 15. Available from www.ergonomics-ohs.com.au. Accessed on 01/12/2010
ERGONOMICS SEATED ASPECTS & THE WORKPLACE THE SEATED MAN We spend a large portion of our day in a seated posture, whether in our places of work or study; or in our leisure time. This seated position, particularly in Western civilizations, is typified by the upright position maintained in a chair in front of a desk. The dynamics of this position would indicate that the body would need to be supported in order to maintain this posture over a longer period of time, to increase productivity and to alleviate the stresses that the body is ultimately put under. The primary areas of support are the lumbar area (Fig 16) and the seat, where the hip and sitting bones rest and carry the weight of the body. The relevance of ergonomics in the consideration of the seated position is the use of the average measurements of these areas of the body applied to the design of seating in order to position the spine in the best possible manner. These may vary from type of chair to application, but some constants will remain in terms of measurements and requirements. The critical measurements related to the seated man will be those of the seat height and seat depth. (Fig 17). If the seat surface is too high, the soles of the feet do not make proper contact with the floor, making the body unstable. When sitting in this position, the thighs become compressed and blood circulation constricted. Conversely, if the seat level is too low, there would also be a degree of instability. With the legs extended and positioned forward, the upper part of the body would be pushed forward as well, forcing the back out of line and removing any support to the lumbar area. (Fig 18) A short seat will similarly add to the sensation of falling off the front of the seat while a seat which is too long will add to a pinching of the area behind the knees and bad circulation. (Fig 19) (ERGONOMICS & SEATING) Along with the seat and the implications of the size and height of it, the body will also end up transferring some of its weight to areas such as the floor, back rests and armrests. Returning to the lumbar area, the means of creating comfort here includes the allowance for an inclination backwards in the seat back (between 105 and 120 degrees) and a minimum of 5cm allocated to the support for the lumbar to decrease disc pressure. This is in practical terms is specifically relevant to the design of office chairs where the emphasis is on streamlined components with a certain degree of flexibility. The degree of inclination and angle between seat base and back is less ideal in an office tasking situation where one is leaning over a desk. Fig 16. Available at www.eorthpod.com. Accessed on 1/12/2010
Designs such as a kneeling chair have taken steps towards greater ergonomic efficiency and the angle specified above is instead rotated to incline towards a desk rather than away from it. The spine is still kept in alignment and the pressure is reduced in the seat area, instead the weight bears on the shin area and not on the knees as it appears. (Fig 20) As with other chairs, the kneeling chair should be used with combination with periodic flexing or extending of each leg to relieve the body. Movement and variation are important factors to making a chair more comfortable and user-friendly and consideration of these factors contribute to the acceptance of these types of chairs by ergonomists and chair manufacturers. In standard chair designs, armrests reduce the weight that would be normally distributed to the seat, but there still need to be a degree of flexibility to allow for the differences in body shapes. The ideal office chair should comprise the following in order to provide sufficient support in a variety of sitting postures: Ability to raise and lower the chair level, and arm heights Sturdy frame Support (lumbar) It is best to ensure that your backrest corresponds to the natural curvature of your spine Padding - there needs to be enough for support (without losing shape) Consideration should be shown for the main components such as backrest; seat; armrest; base Ability to have your feet rest flat on the floor or footrest Correct level of armrests to allow shoulders to relax and elbows to stay close to the body Ensure that your chair has a 5-leg base with rollers for easy movement Manufacturers such as Formway and Knoll have done extensive research into the specifics of seating and the variations on the way that we sit throughout the day. They found out that the act of sitting is a combination of positions, not just the upright position and thus looked at creating chairs that adjust to the user. From this, the concept of holistic ergonomics was developed. By definition this term describes a discipline of designing products that encourage free expression, creativity and engagement in the workplace ; in response to the theory that there is not one right way to sit and that a chair should support a variety of postures. (Fig 21) The chair below, the Aeron Miller chair is said to be the most ergonomic of office chairs, taking into account the basic needs and dimensions suited for ultimate comfort and productivity. (Fig 22) Fig 20. Available at www.echair.co.nz. Accessed on 01/12/2010 Fig 21. Available at www.gentlemansgadgets.com. Accessed on 01/12/2010 Fig 22. Available at www.besthousedesign.com. Accessed on 01/12/2010
(ERGONOMICS IN THE WORKPLACE) Following on from our previous discussions on HCI (Human Computer Interaction), the design interfaces of such interaction between people & our hi-tech world need to be clear and user-friendly. To follow are some guidelines to compensate for the unnatural elements of computers within the workplace. Chair o Easy to adjust along with the ability to vary angles and levels of back support and seat pad o The weight of the body should be easily distributed o An upright posture easier to maintain if the seat pan is tilted slightly forward of the horizontal o Feet should rest flat on the floor o The underside of knees should be level with the seat pan o Footrests and armrests can be added for extra comfort o A sturdy 5-point base helps to Keyboard o Should be in comfortable position whereby wrists are suspended above so that wrists and forearms create a straight line o Hands should glide over knees o Wrist pads (when required) o Flat vs. incline positions; o Split and curved options o Voice recognition options Mouse o To be positioned next to the keyboard within easy reach o Additional wrist support / an adjustable mouse platform Monitor o To be directly positioned in front of the user, with the top of the screen at / below the line of site. o Viewing distance should be 30-50 cm o Head to be kept in a comfortable upright position o Tiltable screen o Antiglare filters o Large enough screen size
To avoid factors such as eyestrain the following items should be considered: An adjacent copy holder to support material Lower levels of lighting to decrease glare; softer overall lighting with task lights HVAC controls (heating, ventilation & AC) Work pace and rest breaks The table shown in Figure 23 takes into account elements of flow, adjustability, minimum space requirements and ergonomics as a guide in determining the overall design. It is powered by motors that allow for easy adjustment and interaction. The keyboard pictured in Figure 24 has taken into account the basic requirements with regard to the position of the wrists in order to allow for ease of use and a more productive interaction. Similarly, as a result of evaluating the ergonomic principles that might affect its use, more ergonomic mouse designs have been developed for use. (Fig 25) Fig 23. Available at www.ergonomicsmadeeasy.com. Accessed on 01/12/2010 Fig 24. Available at www.guinervaprotector.com. Accessed on 01/12/2010 Fig 25. Available at www.ohgizmo.com. Accessed on 01/12/2010