Design for ergonomic and safety Thiết kế bảo đảm an toàn và công thái học

Thiết kế bảo đảm an toàn và công thái học, báo cáo tổng hợp nhiều nguồn, ngôn ngữ: tiếng Anh Prepace: Todays feature is that the growing domination of automation and therefore the new production and technological conditions are set before the industry to rework production activities. The dynamic development of latest technologies and also the investment in new machines, devices, tools and equipment sets the requirement to seek out solutions and make conditions which will make sure the humanization OD work. There has always been an urge to arrange and perform employment that may end in less fatigue and energy losses, the protection in working area is additionally considered, during this report, well specialize in the planning for safety and ergonomic.

Class: Design for manufacturing and Assembly

Report assignment

INTRODUCTION TO DESIGN FOR SAFETY AND ERGONOMIC.

Lê Dương Khánh Duyng Khánh Duy

Khúc Lâm Đ ngồng

Today's feature is that the growing domination of automation andtherefore the new production and technological conditions are set before theindustry to rework production activities The dynamic development of latesttechnologies and also the investment in new machines, devices, tools andequipment sets the requirement to seek out solutions and make conditionswhich will make sure the humanization OD work There has always been anurge to arrange and perform employment that may end in less fatigue andenergy losses, the protection in working area is additionally considered,during this report, we'll specialize in the planning for safety and ergonomic

About Design for safety:

Anyone who designs a product or system involving hardware and/orsoftware needs to ask the following questions and seek answers to:

• Will my designs be safe for the users of the product or system that Idesign for them?

• Will my designs be safe for people who affected by the users of theproduct or system that I design for them?

• Are there any applications that my designs may be used for that arenot safe even though it is not the original intentions of my design?

• Can anyone die or be harmed by my designs?

The designers and engineers that fully answer these questions and takeaction to enhance the protection features of a design are heroes Theseengineering heroes are usually unsung heroes who don’t receive nor seek anyreward or recognition.

When you consider heroes in engineering, you would possibly saydiscoverer of Nikola Tesla or Thomas Edison made significant contributions tothe advancement of a secure world in terms of developing commercial power

to light homes in the dark and prevent fires thanks to lit candles ignitingwindow dressings or draperies We are sure you'll agree that commercialpower saves lives, indirectly As results of commercial power, most home firescaused by candles lighting a home at the hours of darkness are prevented, butfires reception will still occur no matter the employment of business powerreplacing candles

In the period of World War, safety consideration appearances also inweapon design One example of a design for feature that was installed on anexisting product is that the “safety mechanism” designed for firearms asecurity catch mechanism or safety switch used for pistol and rifle designswas intended to forestall the accidental discharge of a firearm, helping tomake sure safe handling during normal use the protection turn on firearmshas two positions: one is “safe” mode and also the other is “fire” mode Thetwo position safety toggle was designed on the military grade firearm, M16automatic In “safe” mode, the trigger cannot be engaged to discharge theprojectile within the firing assembly Other sorts of safety mechanisms includemanual safety, grip safety, de-cocker mechanism, striker block, hammer block,transfer bar, safety notch, bolt interlock, trigger interlock, trigger disconnect,

magazine disconnect, integrated trigger safety mechanism, loaded chamberindicator, and stiff double action trigger pull “Drop safety mechanisms” or

“trigger guards” are passive safety features designed to cut back the prospect

of an accidental firearm discharge when the firearm is dropped or handled in

an exceedingly rough manner

During recent decades, there has been growing awareness of humansafety in the design process The purpose of this paper is to review theliterature on design for human safety (DfHS) in manufacturing systems Tothis end, a process for systematically reviewing DfHS studies was used Theauthors focused in particular on the applications of design theories andmethodologies (DTM) and design tools and techniques (DTT) to analyses andidentify work situations in order to improve human safety in manufacturingsystem design The authors also tried to identify the design phases in whichthese DTM and DTT could be applied This research review covered paperspublished between 1980 and 2015, and combined seven groups of terms:DfHS, design, safety, DTM, DTT, risk and working situation A critical analysiswas also performed in view to defining a research agenda and the mostprominent key actions capable of pointing out paths for future research

About ergonomic:

Ergonomic, in short term, is defined as the study of the design of aworkplace, equipment, machine, tool, product, environment, and systemwhich takes into consideration human being's physical, physiological,biomechanical, and psychological capabilities and optimizes the effectiveness

and productivity of work systems while assuring the safety, health, and being of the workers.

well-Every day billions of people around the world go to work Work isfundamental to human societies Work partly defines us as individuals, andcertain professions can serve as status symbols Many people spend years ineducation systems training for a work career Losing one’s job can be asignificant stressor, as can retirement from work Anything that improves theconditions of work has an enormous impact on the well-being of vast numbers

of people Ergonomics is the science of work, and it is a valuable disciplinethat focuses on improving the ability of people to perform work Ergonomicsadopts a systems approach to designing effective work, and that requiresconsideration of relevant cognitive, physical, and organizational factors.Indeed, in the International Ergonomics Association’s description ofergonomics, it describes these three sets of factors Yet there is also a crucialfourth factor, namely, the environment As this book will demonstrate, theergonomic design of the environment is an essential, yet all too oftenoverlooked, component of the work systems design process

All human work, whether physical, mental, or both, occurs somewhere,and the design of the work environment obviously plays a critical role in theability of a person to perform their work Work performance can suffer if theenvironmental conditions are suboptimal, such as workplaces that are toocold or too hot, where the lighting is too bright or too dim, where it is toonoisy, where the air is polluted, or where the work setting is vibrating or inmotion Also, a suboptimal spatial layout of a workplace can detrimentally

affect work postures, which in turn impacts health, wellness, and taskperformance.

Although early humans were most likely nomadic, where possible theyinhabited places and natural structures such as caves, which offeredprotection against elements and predators, and which served as congregationplaces Eventually, some 5000 years ago, developments in agriculture allowedcommunities to settle in specific locations starting the processes ofurbanization and civilization as we now know it At that time, it is likely that amajority of workers did most of their work outdoors, with activities such ashunting and fishing, agriculture, road building, construction, and fightingbattles

The industrial revolution that began around 1750 marked theacceleration in the movement of work from outdoors in fields to indoors infactories In developed countries today, a majority of workers perform theirwork inside some kind of designed structure, such as a building or a vehicle.How well the designed environment supports their work plays a significantrole in factors such as the risks of work-related injuries, accidents, andproductivity

Although the designed environment plays an obvious role in impactinghuman behavior, this often gets overlooked, even in the ergonomic analysis ofwork For example, task analysis methods typically focus on the work contentand the physical actions involved in performing work, and cognitive taskanalysis, workload measurement, and error analysis methods focus on themental processes involved in completing the tasks, yet such methods typically

neglect the consideration of the physical environment design changes thateither positively or negatively impact the work processes We all know frompersonal experience how critical the design of the environment is to thesuccessful performance of work If you use an iPad, you may have struggled toread the screen in bright sunlight because the ambient lighting overwhelmsthe luminance of the screen, or, conversely, you may have struggled to read aprinted menu in a dimly lit restaurant where the lighting is insufficient foreasy legibility of the text You may be an adroit typist, but if you are using alaptop while riding on a bus that is driving along a bumpy highway, you willhave experienced how difficult it is to maintain adequate performance and tominimize errors because the environment is not supporting your ability to dowork You may have experienced feelings of drowsiness when sitting in acrowded meeting in an inadequately ventilated room, and this occurs because

of an accumulation of carbon dioxide Your manual dexterity and cognitiveabilities are substantially impaired by exposure to very cold conditions, andyour energy levels may be set by hot and humid conditions Environmentalconditions, such as the thermal environment, the luminous environment, theacoustic environment, and the vibration, all impact our comfort, health, andperformance Quite simply, we are animals with biological systems that areadapted to a relatively narrow range of environmental conditions, and if weare to be successful when inside human-designed enclosures, ranging fromsubmarines to spacecraft, from cars to buildings, then we must pay closeattention to optimizing these environmental conditions to maximize ourability to perform work efficiently and effectively

This report provides an outline of those environmental requirements.But just knowing the environmental conditions by itself isn't sufficient to

confirm that our performance is optimized Our capabilities are limited by ourchronobiology—there are times of the day once we expect to be able to sleepand other times after we are alert Unfortunately, in our 24/7 societies, thereare many roles that need people to figure at those times of the day when ourbodies are least prepared for this Additionally, our capabilities also arelimited by factors like our size, reach distances, and strength, and then thephysical arrangement of tools and other work artifacts is critical if we are todemonstrate maximum performance ability while minimizing the risks oferrors, accidents, and injuries For example these issues and other relatedconsiderations; this book also presents workplace design considerations for alarge type of workplace settings In most of the settings that are described, theergonomics considerations target physical design issues, and one undeniablefact that remains invariant is that whenever we will position an individual sothey'll perform their work while in an exceedingly neutral posture, whethersitting or standing, then we are going to maximize their physical capabilitiesand their endurance and minimize the chances of developing work-relatedinjuries.

The application of ergonomic principles in the workplace can result inthe following:

• Increased productivity,

• Improved health and safety of workers;

• Lower workers' compensation claims;

• Compliance with government regulations such as Occupational Safetyand Health Administration (OSHA) standards;

• Improved job satisfaction;

TABLE OF CONTENTS

PREFACE I

SECTION I 1

APPLIYING ERGONOMIC FOR SAFETY DESIGN IN THE WORKPLACES 1

CHAPTER 1: DESIGN FOR ERGONOMICS 2

1.1 THE ERGONOMICS-DESIGN RELATIONSHIP: 2

1.1.1 Introduction to Ergonomic: 2

1.1.2 The Ergonomics-Design Relationship 4

1.2 DESIGN FOR ERGONOMIC, REAL-LIFE EXAMPLE: 6

1.3 HUMAN-CENTRED DESIGN – UX_USER EXPERIENCE: INTERVENTION METHODS AND TOOLS 13

1.3.1 Introduction 13

1.3.2 Human-Centred Design Methods 14

CHAPTER 2 17

HEALTH, SAFETY AND ERGONOMIC 17

2.1 THE CONTRIBUTION OF ERGONOMICS TO INDUSTRIAL SAFETY AND HEALTH 17

2.1.1 Areas of Safety 17

2.1.2 Hazard and Hazard awareness 18

2.1.2.1 Immediate hazards 19

2.4.2 Delayed hazards 22

2.4.3 Hazard awareness 24

2.4.3.1 Risk homeostasis 26

SECTION II 37

CHAPTER3 38

DESIGN FOR SAFETY 38

3.1 DEFINITIONS 38

3.2 INTRODUCTION 39

3.3 THEORETICAL FRAMEWORK 43

3.3.1 Hazards and risks 43

3.3.2 Safety 46

CHAPTER 4 47

SAFETY DESIGN 47

4.1 UNDERSTANDING AND SPECIFYING THE USAGE CONTEXT; DEFINING THE DESIGN REQUIREMENTS; PRODUCING THE DESIGN SOLUTIONS 47

4.2 HUMAN-CENTRED DESIGN METHODS 49

4.3 SAFETY IN DESIGN 68

4.3.1 Approaches to design 68

4.3.2 Safety in general problem solving 69

4.3.3 Integration of safety into the design process 75

4.4 APPLICATION OF THE APPROACH IN THE DIFFERENT DESIGN STAGES 80

4.4.1 Task clarification 80

4.2.2 Determination of functions and function structure 81

4.2.3 Search for solution principles 83

4.2.4 Division into realisable modules 86

4.2.5 Development of the layouts of key modules 88

4.2.6 Completing overall layouts 90

4.2.7 Detail design 92

SECTION I

APPLIYING ERGONOMIC FOR SAFETY DESIGN IN THE WORKPLACES

Chapter 1:

Design for Ergonomics

1.1 The Ergonomics-Design Relationship:

1.1.1 Introduction to Ergonomic:

The IEA (International Ergonomics Association) defines Ergonomics, orHuman Factors: “Ergonomics (or human factors) is the scientific disciplineconcerned with the understanding of interactions among humans and otherelements of a system, and the profession that applies theory, principles, dataand methods to design in order to optimize human well-being and overallsystem performance

Practitioners of ergonomics and ergonomists contribute to the designand evaluation of tasks, jobs, products, environments and systems in order tomake them compatible with the needs, abilities and limitations of people” Thecentral focus, therefore, is the interaction that people establish or canestablish with other elements of the system in which, and with which, theywork and carry out daily activities An interaction, therefore, take place within

a complex system, in which each element conditions and modifies the othersand which people, with their characteristics, abilities, needs and expectations,form an integral part of

The goal of Ergonomics is to optimize, that is, improve to the highestpossible degree, both the well-being of people and the overall performance of

the system, through evaluation and design activities that aim to make systemsand environments compatible with people’s needs, abilities and limitations.Thus, Ergonomics is based on a complex approach to the evaluation anddesign of the interaction between people and the systems they come intocontact with, one that does not focus on the quality of the system itself but onthe quality that is actually experienced by the specific group of people whohave contact with it, depending on their characteristics, abilities, needs andexpectations, the activities they perform and the collection of variables(physical, technological, environmental, organizational, cultural) that mayaffect that interaction on a case-by-case basis.

The meaning of the terms used is essential for understanding thedefinitions

The term product refers to its literal meaning of “a result of humanactivity” and, in the case of industrial products, the result of a design andproduction process that aims to respond to a specific need Products,therefore, are the objects to be used, the environments, the services—and,more generally, the systems—whether physical or virtual, which will all bereferred to in this book using the term product

The term needs refers to something that is “necessary for performingsomething” and, more generally, to the collection of needs, requirements,expectations and desires that people express—knowingly or unknowingly—with regards to their use of, or relationship with, a product or a system

For brevity, the term needs will be used in the text to refer to thismeaning.

1.1.2 The Ergonomics-Design Relationship

For a protracted time, the connection between Ergonomics and styleand between Ergonomics and style has been on the perimeter of therespective intervention fields Until the 90 s, the connection betweenErgonomics and style was thought to be one in every of two distant worlds:the previous, one in every of rules, evaluation methods and technicalregulations, the latter, of design ability and artistic freedom

In the field of ergonomics,the intervention of the designer

—architect or designer—wasmainly required at the top ofthe evaluation process conduct

by professional ergonomists,who were specialists within thefield of physical or cognitiveErgonomics The designer wasasked to produce a designresponse for what emergeduring the evaluation phase,and to use his skills to search

out the solution—design, to be exact—during the ultimate phase of everyintervention.

In the field of design, the architect’s training did not fail to include— nordoes it include now— any teaching or awareness of the sphere of ergonomics.The designers—researchers and/or professionals—turned to the talents ofergonomists for instructions and advice outside of, or parallel to, theformation and development of design Obviously, there are some exceptions,many of them well-known, chiefly represented by large companies that havealways been mindful of the security and wellbeing requirements of theirproducts and attentive to the essential contribution made by Ergonomics Therole of Ergonomics is precisely located in research centers with specific skillsdedicated to evaluation safety, the anthropometric and postural aspectsand/or cognitive aspects of the finished products and, in parallel, the healthand safety of labor stations and locations within the corporate one in all themost effective known is that the FIAT Research centre, within which thesectors dedicated to Ergonomics are traditionally divided into physical andcognitive Ergonomics and therefore the Whirlpool Ergonomics and value(today, User Experience) Centre, the activity of which is known as after theevolution of the User/Human-Centred approach In terms of the planet ofdesign, the role of certain designers and designers who have always beenclosely linked to Ergonomics and active within the field of ergonomics sincethe ‘70s is extremely important Two of those are Luigi Bandini Buti and IsaoHosoe

Bandini Buti, the primary and most famous Italian designer to callhimself an “ergonomist”, is accountable for design and research explicitlyplaced in an ergonomic context that represented the purpose of departure andreference for all people who developed their own design businesses—researchers and/or professionals—in the sphere of Ergonomics and Human-Centred Design His academic contribution at Milan Polytechnic and also themany other Italian colleges where he taught and continues to show is of greatimportance; it's allowed generations of Design students to interact with

Ergonomics in such some way on create designs focused on therequirements and desires of individuals The role of Isao Hosoe is of equalimportance His products, which are well-known nationally andinternationally, have represented perfect samples of Design and Human-Centred design for several decades Until the ‘90s, however, these wereunique cases within the academic and professional image of Design; theirdesign intelligence and talent is to blame for constructing the foundations ofErgonomics and style

1.2 Design for Ergonomic, real-life example:

Even if it is not possible to identify a specific date or event that officiallymarks the beginning of a concrete integration between Ergonomics andDesign, certain phenomena have marked their gradual progress and, in thelast two decades, the growth of an area of Ergonomics that is specificallydirected towards design and, in parallel, an area of Design that takes itstheoretical and methodological contents from Ergonomics, in particular, theHuman-Centred Design approach

The first of these is the growing attention of companies towards thequality of the products and services it offers to consumers, focused initially onthe desire to ensure—and publicize—high levels of safety and usability for theproducts and services on offer and, secondly, on the attention towards what isknown today as the User Experience, that is, on the quality of the globalexperience—in terms of experience and impact—experienced by the peoplewho use and interact with the product, the environment or the service, be itphysical or virtual.

The second, though it seems obvious today, is the dissemination ofdigital technologies and languages in the majority of everyday products andthe need to guarantee high levels of user-friendliness in digital interfaces andtheir infinite applications

The dissemination of dialogue screens and means of digital interaction

in household appliances, cars, communications devices, ticket dispensers,vending machines and, finally, care devices (from medical equipment tosupports for movement that can also be used in homes), etc has created newlevels and means for market competition for companies, which is often based

on the ease and instant understanding of how to use the dialogue interfaceand the aesthetic and sensory appeal of the shapes, materials and surfacetreatments used on the products themselves

Making products safe, easy to use, pleasant and instantlyunderstandable, and making these qualities immediately apparent at the

moment of purchase, has become one of the chief factors in success on themarket in recent years.

Design is called upon to create solutions capable of guaranteeing—andpublicizing—the quality of the product in terms of the user’s safety and well-being, its ease of use and, finally, the user experience, focusing on the needs,expectations and desires of the people who will choose and/or use theproduct and favour it over the myriad others that are available on the market

In fact, as Norman writes (1998, p 48), “Ease of use has many benefits

for a company Not only are customers more likely to be satisfied with the product, but the need for service desks should decrease (…) In the mature marketplace, where there is fierce competition, relatively low prices, and low profit margins, a single call from a customer can often cost the company enough

to wipe out any profit from the sale of the item Here is where one of the largest economic impacts of good product development can be measured (…) In addition, satisfied users become repeat purchasers, likely to recommend both the product and the company to friends and colleagues, enhancing the overall reputation”.

Therefore, it is up to companies to request a Design centred on the usertension, the person, in a series of requests that begins with a focus on thesafety levels when using the product and then on the comfort levels and well-being of household and office furnishings, on the simplicity of using thephysical and digital interfaces (referred to and publicized as ease of use, userfriendliness, up to the definition recognized as “usability”, particularly for

digital interfaces), up to the aesthetic and sensory appeal and, finally, the userexperience.

This course, which also explains the strong development of Ergonomicsand Design/Ergonomics in Design, both in Italy and in other countries that aredealing with a much less marked, or even absent, development in other areas

of Design, particularly as it relates to Architecture, has naturally followedsubsequent phases in both the professional and academic fields Design isprogressively approaching

Ergonomics, which provides precisely this knowledge and theseintervention methods to guide the entire training and product developmentprocess, starting from the needs and expectations of people and, in parallel,Ergonomics is approaching Design as a repository of design-interventionskills, capable, by definition, of “giving shape to the product” by synthesizingthe contributions and knowledge of people’s current and potentialexpectations in the design An essential transitional moment in thisintegration process is the 1988 publication of the ISO 9241/11, Ergonomicrequirements for office work with visual displays terminals (VDTs) Parte 11:guidance on usability regulation, which has become an essential point ofreferences for all designers involved in ergonomics

As has been written by numerous authors on a number of occasions, theISO 9241-11:1998 regulation (which has now been replaced by 9241-210:2010) contains definitions and methodological guidelines aimed at

evaluating and designing information systems, but is general enough to be ofinterest in every field of design.

The publication of many of Donald Norman’s books in Italy is also of

great importance The most famous of these is “The psychology of everyday

things”, which is written in a language that is accessible to those who are not

experts in cognitive psychology It has been adopted for many universitydesign courses and, from the late 90 s, in the first courses for “Ergonomics forDesign”, subsequently becoming a reference text for courses in IndustrialDesign and Design

In the field of Product design, the theme of usability is of strategicinterest, both because the means of interaction between the user and theproduct pose very similar problems to those that characterise HumanComputer Interaction (possibility of error, correct understanding of feedback,analogies between the arrangement of the commands and the parts beingcommanded, etc.) and because the digital language has become an integralpart of everyday products

Design’s interest in the contents of User-Centred Design and the meansfor evaluating Usability was initially born from the direct application ofindustrial products and evaluation methods born in the field of cognitivepsychology to the sector, in order to evaluate the human-computer interaction(or, better yet, the interaction between the person and the digital interface ofthe ICT systems)

Their application in the field of design clashes, however, with objectivedifficulties, due to the evident diversity of the object of analysis, as well as thediverse disciplinary origins in which they were conceived, which comprise, inthe case of designing products and physical environments, elementscharacterized by their physical, morphological, sensory, cognitive andemotional features, which require the global evaluation of the differentdimensions in which people interact with them.

In other words, the relationship with an environment or an object isbased on the possibility of seeing, touching and handling shapes andmaterials, of perceiving their smell, temperature, consistency and, at the sametime, on our ability to understand the ways they work and to appreciate (ornot) their sensory and aesthetic qualities

The development of an area of Ergonomics specifically aimed at design,which is not intended as an application of the contents elaborated in otherfields of research, but as an autonomous research sector in its own right, onecharacterised by the specificity of its theoretical and methodological contents,presupposes the development of a collection of definitions, criteria forintervention and evaluation methods specifically aimed at the design sector.This is capable of constituting a collection of shared, operational tools andreferences and a common basis for dialogue and comparison for the differentprofessional figures that operate within this sector

In fact, Ergonomics and Design shift the attention from the evaluation

design of the interaction between people and the product, environment orsystem, within a specific context, taking into account all of the variables thatcould impact said interaction.

Attention has also shifted from the evaluation of the objective reality—that is, the current situation in which to intervene with corrective oradjustment actions—to the projection into the future, where possible, of thereality of the interaction, and to the definition of the most suitable designsolutions to respond to the needs and desires of the person The ergonomicapproach uses the description and understanding of all of the variables thatdefine the “usage context” as a point of departure, that is, all of the factors thatdetermine the conditions and means in which certain people interact (or areable to interact) with a given product or system

To do this, one must therefore answer some questions to start: what isthe product? Who uses it? Why and for what? Where? How? For how long?

In other words, one must clarify and explain the reference frameworkaccording to the 5W’s of the Anglo-Saxon journalistic tradition (What? Who?Why? Where? When?), adding “How?”

Translating these questions into a design key means adding, in a simplemanner, their declination to the conditional and the future, expanding theattention beyond the current, objective situation (what is happening here andnow; what do users expect in the known situation) to its possible evaluation

Thus, the questions become: who can or could use the product? Whenand how can it be used? Why? Where?

Moreover: in what way could it be used (in the correct way or the wrongway? In the expected way or for other activities or goals?)? In what context(for example, in different settings, with different technologies, etc.)?

And, as a result: what could a new product be?

Today, Ergonomics and Design is configured as Design for people, that

is, an approach to the design that centers—by definition—on the person, withits theoretical and methodological references based on the contents andmethods of Human-Centred Design, closely integrated with the interpretiveand propositional tools used for the culture and practice of the design

1.3 Human-Centred design – UX_User experience: Intervention methods and tools

1.3.1 Introduction.

User-centred design is a structured development methodology to attainsoftware usability, focused on the needs and characteristics of users, whichshould be applied from the beginning of the development process in order tomake applications more useful and easy to use (Averboukh, 2001; Nunes,2006; Nunes and Simões-Marques, 2013; Simões-Marques and Nunes, 2012)

There are different perspectives about the principles that developersshould adopt when designing a product to achieve an appropriate usability

lists usability principles that should be taken into account when designing,selecting, commissioning, and modifying software Jordan identified a list of

10 general principles to observe: consistency, compatibility, consideration ofuser resources, feedback, error prevention and recovery, user control, visualclarity, prioritization of functionality and information, appropriate transfer oftechnology, and explicitness (Jordan, 1998) Reiss presents usabilitytechniques that help improve

product design regarding functionality, responsiveness, and clarity(including its visibility, understandability, logicalness, consistency, andpredictability) making it ergonomic and foolproof (Reiss, 2012) Despite thefact that the breadth, depth, and terminology may vary, the core principles areequivalent Gerhardt-Powals identifed a set of heuristics to improveperformance, which includes automating unwanted load, reducinguncertainty, condensing data, presenting new information with meaningfulways to support their interpretation, using names that are conceptuallyrelated to functions, limiting data-oriented tasks, including only information

on the screens that the user needs at any given time, providing multiplecoding of data (where appropriate), and practicing a judicious redundancy(Gerhardt-Powals, 1996)

ISO 9241 provides requirements and recommendations for human-centreddesign principles and activities throughout the life cycle of computer-basedinteractive systems It is intended to be used by those managing designprocesses, and is concerned with ways in which both hardware and softwarecomponents of interactive systems can enhance human-system interaction

ISO 9241-210:2010 identifies four key activities related with the user-centreddesign* approach, which should be planned and implemented in order toincorporate the requirements of usability in the process of softwaredevelopment: understand and specify context of use; specify the user andorganizational requirements; produce design solutions; and evaluate designagainst requirements These activities are performed iteratively, with thecycle being repeated until the requirements have been achieved.

1.3.2 Human-Centred Design Methods

“Anthropocentric” design, or Human-Centred Design (HCD), is anintervention philosophy that aims to develop products/systems or servicesthat can satisfy people’s needs, so that interacting with them is characterised

by a high level of usability and ease of understanding and can offer a userexperience that is positive and satisfying As part of this vision, the productsmust meet a series of requirements that are based on careful evaluation of theusers’ needs and, naturally, respect for the limitations imposed by productionand marketing needs

As noted in the ISO 9241-210: 2010 standards, once the need to develop

a system, product or service has been identified and, as a result, the referenceproblem, there are four essential steps that must be followed to integrate therequirements for usability into the product/system-development process (Fig.6.1):

(a) understand and specify the context of use;

(b) specify the user requirements;

(c) produce design solutions to meet these requirements;

(d) evaluate the designs against requirements

Fig The human-centred design process

The first two phases are part of so-called “User research”, which isdedicated to “understand and specify the context of use”—i.e., defining theprofile of the users (reference target), the real and potential context of theirinteraction with the new product and explicit and implicit user needs—and to

“defining the requirements” of the design

The second phase for defining the requirements is a result (or, rather,the output) of “User research”

In the third phase of producing “design solutions”, we instead move tothe actual design of solutions based on the requirements (phase a–b) In thefourth and final phased, which aims to “evaluate the designs againstrequirements”, the technical functional aspects and User Experience aspectswill be examined using an iterative evaluation process for the design solutionsthat have been produced and any modifications to them

Within the HCD process, the involvement of the users plays afundamental role in phases a and b (“understand and specify the context ofuse” e “specify the user requirements”) and phase d (“evaluate the designsagainst requirements”)

Chapter 2

Health, Safety and Ergonomic

2.1 The contribution of ergonomics to industrial safety and health

2.1.1 Areas of Safety

The main contributions to safety deriving from ergonomics have, thus,come from the application of its extensive researches Ergonomics was thechild of wartime research into human needs, capabilities and performance,and for the first half of the existence of its professional society in the UK moremembers were devoted to human research than to its application This is nolonger the case today, and a recent survey (Ergonomics Society, 1987) showsthat slightly over half the members of the Ergonomics Society, as in othercountries, are now engaged in virtually full-time ergonomics practice A largeamount of fundamental and applied research continues to be carried out,nonetheless, the fundamental part being undertaken mainly in highereducational and defence establishments, and the applied portion mainlywithin industry

One has to define the various areas of safety involved beforeconsidering the contribution ergonomics can make As the ergonomist sees it,there are two types of safety, that for the operator, and that for others Others'may be divided into those in proximity to the operator, and those distant fromthe operator; 'those distant from the operator' include product consumers and

the public at large In both types - operator and others - there are the effects oftime; thus, one has hazards that are immediate or delayed, the delayedsubsection including the hazards which arise from time, and those which are aconsequence of repetition of activities which impose no hazard if performedonce or only a few times.

If one analyses the ergonomics literature one can get a 'feel' for thegeneral size of the contributions made to these areas over the past 20 years,and one thus arrives at Table 2.1 below

Table 2.1: Ergonomics research contributions to different areas

Table 7.1 appears to reflect the priorities given to safety by many othergroups working in industry It does not, of course, reflect the perception ofsafety requirements of the public at large, but does show the scope of presentergonomic knowledge of value in the safety field It also indicates that hazards

to the general population, while being of high concern, have received the leastattention by researchers.

2.1.2 Hazard and Hazard awareness

That which is unsafe is not ergonomic Many accidents and injuries atwork arise when the work arrangements are not fitted to the

workers capabilities or interests Misfitting may be physical orpsychological Physical misfitting can cause such things as overstrain of themusculoskeletal and cardiovascular systems, and spatial misfitting can causesuch things as postural stresses, over-reaching or bumping contacts.Psychological misfitting is less easy to determine, but may have much widereffects than simple physical causes Sensory misfits may directly affect vision,hearing, olfaction or any aspect of peripheral sensation, or more insidiouslyaffect the central processing of sensory information The latter can thendisturb cognition, and may affect reaction times and cause wrong decisions to

be taken

Equally, such matters as ill-chosen shiftwork times and rest pauses canlead to disturbed thinking and, thus, to serious errors, as can lack ofappreciation of the effects of biological rhythms Knowledge of these factors ispart of the economist's armoury for designing satisfactory and, hence, safeworkplaces, and this research has contributed much to safety considerations.These many contributions are considered above in relation to Table 2.1

2.1.2.1 Immediate hazards

The ergonomist, while having concern for matters contributing toimmediate dangers such as the coefficient of friction at the shoe-sole interfaceand the lack of splintered surfaces and sharp edges, has been more concernedwith ensuring that the workplace matches the size and abilities of the worker,and that the worker is able to control tools or machinery without posingimmediate personal or social hazards.

There have thus been major anthropometric studies of males andfemales of different ages in many working populations, some of theseculminating in the production of guidance mannekins, or definitions of spatialoptima and their variances for the whole, and different parts, of the humanbody, in a large variety of occupations (see, for example, Pheasant, 1986).Studies of the space requirements for normal and laden locomotion have alsoled to considerations such as tread heights and depths for stairways, theslopes of ramps and their widths in relation to task needs In the field ofphysical work, tissue, muscle, limb and whole body strengths have beendetermined - again for a number of different populations - and a reasonablepicture of the spread of physical capacities is now available (see, for example,Chaffin and Andersson, 1984) Physiologists have investigated thecardiovascular abilities of working people, and have measured the energydemands of many tasks and occupations However, it is clear that much moreknowledge regarding females is required, partly because of past lack ofinterest, and partly because in Western societies their physical capacitiesappear to be increasing faster than those of males

The effects of posture and load size, shape and weight have all beenstudied widely, and the optimal sizes and locations of handles for variousloads have been determined The physical effort required for many tasks hasbeen measured in this regard, and the effects on these of altering tool or leverdimensions, required force and shape have been recorded One factor perhapsworth highlighting in relation to immediate hazard is the interplay betweenthe magnitude of effort and the perception of the adequacy of its control.

Much attention has been paid to visual abilities The needs for optimalacuity for different types of task have been defined, and the effects on these offactors such as luminance, glare, flicker and colour are well documented Theoptimal sizes of print for different purposes has been established, and thelegibility of a range of fonts compared The factors involved in clear visualdifferentiation of control functions have been determined

Acoustical studies have included the effects of noise on speechrecognition, allowing prediction of error rates at different levels ofinterference, and the effects of different levels of noise on cognition, decisionmaking, learning processes, and such matters as calculation and hand-eye co-ordination Criteria for the efficiency of protective devices have beenestablished, and it is now possible to prescribe optimal sound levels for giventasks Much of the initial research in ergonomics was concerned with controlsand their associated feedback devices Indeed, there was a time when thegeneral public thought that ergonomics was 'knobs and dials', but fortunatelythat partial misconception has passed Nonetheless, control systems continue

to be an important part of ergonomics and research continues The original

observations included studies of dial sizes, types and positions, the best sizes,colours and uses of knobs and levers, and the optimal placements of these inrelation to frequency and/or urgency of use Such observations led on to therealization that every control situation had to be thought of as a 'system'rather than as a series of isolated objects, and this involved the development

of studies into hand-eye co-ordination, reaction times, and the whole area ofdecision making Many case studies illustrated the possible immediateadverse effects of bad provision of control devices, some of these being ofcatastrophic proportions The increasing complexity of industrial systems had

to be met by studies of human capacities to absorb, remember, digest and actsafely on multiple sources of information

Inherent in all these matters has been the question of fatigue and theeffects of stress on functional integrity and safety Many investigations havebeen reported into the effects of physical and mental fatigue on all types ofperformance, and some of these have been associated with parallel studies ofthe interplay between direct fatiguing factors and environmental conditions.Various measures of fatigue have been postulated and assessed, and althoughnone of these has been of universal application, the battery of tests nowavailable allows fatigue measurement in most circumstances Thus, accidentsarising from this cause can generally be ruled out at the planning stage

2.4.2 Delayed hazards

Delayed hazards include such adverse effects as accumulated toxins,chronic radiation over dosage, cumulative skeletal pathology and long-term

visual strains The contributions of ergonomics to some of these problemshave been small, but there have been major advances in the control of others.Those resulting from adverse conditions only as a result of time have led someergonomists into the difficult field of ageing, since some effects are barelydistinguishable from normal ageing processes.

One example has been the use of epidemiological studies in parallel withergonomic analyses of workplaces which have led to recommendationsregarding future designs One instance here is the redesign of an oil-can fillingmachine, in such a way that the operators handling the cans could not becomecontaminated and the risk of chronic skin lesions was greatly reduced Some

of the bigger contributions have been in the area of atomic energy, wheremajor ergonomic appraisals of power stations, including control systems andindividual workstations, have improved work efficiency and considerablydecreased acute and cumulative radiation hazard It is interesting in thisregard to note that full-time ergonomic input has been arranged into theplanning of operational safety in new British nuclear power stations, partly as

a result of intercession by the British Ergonomics Society

Another major contribution has been the research into cumulativephysical trauma Epidemiology has shown that some physical stresses may bewell within safe capacity when they occur only once, but that if repeated overperiods of hours, days or years may have serious effects These include suchinjuries as vibration white finger, tenosynovitis, cervical spondylosis, and asignificantly large proportion of cases of back strain Much effort in recentyears has been devoted to establishing force limit tables whose application

should help to obviate such injuries The guidance limits so far have beenconcerned with short- and medium-term effects; lifetime exposure has yet to

be studied fully However, short- and medium-term guidance levels for somevibrations are fairly well-established, as are those for the prevention ofcumulative back injuries (Materials Handling Research Unit, 1980) and arebecoming incorporated in guidance documents across the world; those forother disorders are still being investigated, but it seems likely that ourknowledge of limits for repeated limb and head stresses will soon result insimilar safety indicators The methods used in back research includepsychophysical studies, in which the subjects judge for themselves whatforces they would be prepared to apply: a comparison of these results withthose from other methods shows that, for some actions, subjects will applyrepeated forces, which an investigation by Nicholson (1986) suggests may behazardous This makes it clear that external measurement of physical work isnecessary for full safety

There is a growing realization, also in relation to delayed skeletaldisorders, that prolonged maintenance of posture can lead to cumulativeinjuries While there have been many studies of sitting posture and supportdesign, many of these have been concerned with short-term effects Some ofthe epidemiology referred to above has shown that workstations whichdemand long continued maintenance of a rigid posture of any kind can causeimmediate or short-delay discomfort, and also have an associated high rate ofdelayed injury Data are emerging which can be used as indicators of safetolerance times for such situations

2.4.3 Hazard awareness

It would seem axiomatic that a high level of hazard awareness and arealistic assessment of the risks involved in a job are prerequisites of aneffective safety programme, yet until recently these topics have received littlemore than passing reference in the literature on occupational safety This may

be partly because they are so 'obviously' an aspect of the safety equation thatthey have never merited specific discussion After all, what is the purpose ofsafety training if not to make people aware of the hazards and risks of theirwork? Similarly, it may be partly due to a change in semantics and partly aquestion of nuances of interpretation For example, the concept of accident-proneness, once so prominent in the safety literature, could equally beinterpreted as a function of poor hazard awareness and risk perception ratherthan a fundamental personality trait The classic paper by Hill and Trist(1953) which identified a relationship between accidents and absenteeism,and interpreted this on the basis of psychological withdrawal, could likewise

be explained by failures in hazard and risk perception In fact, as we shall seelater, this interpretation has been vindicated in a subsequent study Whateverthe reason for this apparent paradox of central issues receiving littleattention, it remains true that the systematic consideration of these factors inaccident research is a relatively new development

Obviously separate concepts, hazard awareness and risk perception are,

in practice, so interlinked that they can be treated as effectively two sides ofthe same coin; the individual's personal awareness of danger is intrinsic to hisworkplace and working practices

Recent studies in this area fall into two categories: (1) those associatedwith the theoretical concept of risk homeostasis; and (2) a more diffuse groupwhich, for the want of a better phrase, can be called the pragmatic studies.This latter group have little in common other than their acceptance that moreinformation on hazard and risk perception may be of value in theunderstanding of the causes of accidents

2.4.3.1 Risk homeostasis

The theory of risk homeostasis (proposed by Wilde, 1982) states thatpeople adjust their behaviour to changing circumstances in order to keep theobjective risk essentially constant Although this may appear at first to be arather extreme idea, it is apparent in many everyday situations Howarth(1987) provides an excellent example: we tend to drive faster on wide, clearroads and slower on the narrow, busy roads in town Given that increasingspeed increases the risk of an accident, it can be seen that effectively weincrease the risk on the relatively safe roads while decreasing the risk onrelatively dangerous ones Although risk homeostasis has the merit ofapplicability to everyday experience and, as we shall see below, someexperimental support, it has proved extremely controversial The reason forthis is that if the theory is true universally, any attempt to improve safety byengineering inevitably will fail; whatever changes are made, the theorypredicts that people will simply change their behaviour in order to return tothe level of risk that prevailed before the 'improvement' was introduced

Two recent papers, Howarth (1987) and McKenna (1985), review bothstudies in relation to this concept and its underlying principles; it is thereforesufficient simply to provide a flavour of the debate Most of the studies lendingsupport to the theory have been related to road traffic accidents The basicapproach taken is essentially to predict the effect of a safety improvementprior to introduction and measure the effect afterwards Any shortfall is thenexamined to see if there is any way in which it can be explained on the basis ofbehavioural adaptation For example, Wilde (1982) cites the evidence that,while the introduction of traffic-lights changes the type of accident, it does notinfluence the level of casualties Conybeare (1980) presented data whichshowed that the compulsory wearing of seat belts in Australia had no neteffect Although the number of occupant injuries went down, the number ofnon-occupant injuries went up Rummer, et al (1976) showed that on theintroduction of studded tyres to improve grip in icy conditions, the benefitwas negated - the drivers simply used the extra grip to drive faster Each ofthese studies has been interpreted as supporting the concept of riskhomeostasis Several other papers in support of the theory have also beenreported (see, for example, Wilde, 1984) and some examples have beensuggested to show how the theory could be used to provide incentive schemes

to promote safe driving (Wilde and Murdoch, 1982) However, there are also anumber of papers which claim to refute the theory or, at the very least, lend

no support in circumstances where supporting evidence might legitimately beexpected For example, Huddart and Dean (1981) have reviewed the evidence

on the influence of highway modifications (which according to the theoryshould have no lasting effect) and shown that, while not all are successful in

reducing accidents, many can be shown to have been extremely successful.Several studies of seat belt applications have been published which similarly

do not suggest any form of behaviour compensation (e.g von Buseck, et al.,1979; Evans, Wasielewski and von Buseck, 1982)

Risk homeostasis has also been attacked in terms of the evidenceavailable on the basic assumptions made For example, people must be able,for the theory to make any sense at all, to make reliable assessments ofsubjective, and objective, risks inherent in a situation There is, of course,much evidence that people are poor at risk estimation (especially the levels ofprobability associated with accidents) and of the variability of suchestimations (see Slovic, Fischoff and Lichenstein (1981) for a review)

Both sides in the debate unfortunately leave themselves open tocriticism from the 'opposition' in terms of methodological limitations and ofselective use of supporting literature For example, the supporters of riskhomeostasis favour the emphasis given above on the results of the Rummer,

et al study The detractors point out that, while drivers did increase theirspeed with studded tyres, this was marginal compared to speeds to beexpected if the conditions had not been icy It seems unlikely, therefore, thatthe theory will be vindicated or otherwise without considerably moreinvestigation The value of the theory itself may be limited, but there can be nodoubt that the debate it has produced has highlighted the importance of riskperception in the understanding of accident causation, even if it has failed toshow convincingly that it is the only issue of real significance