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What are Human Factors?
Conceptual Understanding: Design is human centred and, therefore, designers need to ensure that the products they design are the right size for the user and therefore comfortable to use. Designers have access to data and drawings, which state measurements of human beings of all ages and sizes. Designers need to consider how users will interact with the product or service. Use and misuse is an important consideration.
Define the term ‘Human Factors'
The term Human Factors is used for the combination of ergonomics and anthropometrics. Human Factors is also known as comfort design, functional design, and user-friendly systems, is the practice of designing products, systems or processes to take proper account of the interaction between them and the people that use them.
What are the aims of Human Factors?
Reduce stress and fatigue on people, as they will be able to do things faster, more easily, more safely and make fewer mistakes (reduce errors)
Increase safety
Increase ease of use
Enhance operational comfort
Improve system performance, reliability and maintenance
Key aspects of Human Factors provide:
effectiveness (completeness and accuracy)
efficiency (speed and effort)
engagement (pleasantness and satisfaction)
error tolerance (error prevention and error recovery)
learnability (predictability and consistency)
Evaluate the Human Factors of these tin / can openers using the Key aspects of Human Factors as a checklist
What is Ergonomics?
The application of scientific information concerning the relationship of human beings to the design of products, systems and environments.
Ergonomics most often deals with the work related subjects of:
posture; worksite development operating layout; material handling
repetitive stress and movement; repetitive stress injuries and musculoskeletal disorders
occupational safety and health. The aspect of ergonomics that deals with body measurements, particularly those of size, strength and physical capacity.
Comment on the ergonomic issues in the design of an office working ergonomic and the pizza slicer consider the following:
What is Anthropometric data?
The aspect of ergonomics that deals with body measurements, particularly those of size, strength and physical capacity.
It is used to assess the size, shape and composition of the human body and can be sub-classified as Static and Dynamic Anthropometric Data.
Static (structural) data:
Human body measurements when the subject is still (refers to measurements taken while the subject is in a fixed or standard position, e.g. height, arm length).
Static Data (also known as Structural data) refers to measurements taken while the subject is in a fixed or standard position, e.g. height, arm length.
Static data is much easier to gather, as people are asked to remain still while measurements are taken.
Skeletal dimensions – measurements of length of bones between joint centres.
Why does the collection of anthropometric data have some limitations and issues with reliability?
Tools used to collect Static anthropometric data:
It is sometimes difficult to collect accurate anthropometric data mainly due to the reliability and limitations which are described below.
Tools used: Unreliability may have arisen from the tools used to perform anthropometry
Personnel training: anthropometric techniques are prone to errors that could arise, for example, from the inadequate training of personnel
Time of the day: because the cartilaginous discs of the spinal column get compressed by body weight throughout the day we tend to be slightly shorter in the evening up to 22mm
Person’s body shape: problems from collecting accurate data from nude or clothed people ( people work with shoes and cloth)
Users do not carry tasks in the same way: so data may be unreliable when observing user behaviour
Obtaining static data is straight forward: but users interact with products and systems dynamically making accurate data gathering difficult to obtain.
Explain a design context where static data collection would be considered. Attempt to use key terms from the Human Factors, Ergonomics and Static Data tables. Try to use key terms including: Anthropometric data, ergonomics, human factors, static data, data collection tools (attempt to identify them)
Dynamic (functional) data:
Human body measurements taken when the subject is in motion related to range and reach of various body movements. E.g. crawling height, overhead reach and the range of upper body movements.
Remember that people carry out tasks in many different ways. While static data is more reliable, dynamic data is often more useful. As dynamic/functional data includes dynamic data measurements while performing a required task e.g. reaching abilities, manoeuvring and aspects of space and equipment use.
Human Motion Capture software, videos and tracking software are used as a tool to collect Dynamic Anthropometric Data?
Explain how Human Motion Capture software works and what some of the pro’s and con’s are.
Explain a design context where dynamic data collection would be considered and identify the tools that could be used to collect the data.
Data Collection
Primary data (research)
Data collection (also called field research) involves the collection of data that does not already exist. Data collected by a user for a specific purpose.
Done by yourself- e.g a questionnaire or measuring the size of a user. The advantage of the primary research information, is that the data has been collected personally. Therefore, it relates directly to the researcher's study. Depending if it's quantitative or qualitative research it can also include a large sample size or a smaller sample size.
List examples and the advantages and disadvantages of primary research?
Secondary data (research)
Data collection (also known as desk research) involves the summary, collation and synthesis of existing data. Data has been collected by someone other than the user. For example: Anthropometric data collected by scientists.
Advantages of Secondary Market Research are Time and Cost efficacy: Usually time and cost required to collect secondary data is less than the efforts required to collect primary data. Data is available freely or at a far lesser cost through secondary sources.
List examples and disadvantages of secondary research?
Qualitative data
Typically descriptive data used to find out in depth the way people think or feel - their perception which is very subjective from person to person.
Qualitative data is typically descriptive data and as such is harder to analyze than quantitative data.
Quantitative data
Quantitative data is information about quantities; that is, information that can be measured and written down with numbers.
Some examples of quantitative data are your height, your shoe size, and the length of your fingernails.
Justify why both qualitative and quantitative data are needed. Use an example of a design context.
Ergonome and Manikin
What is an ergonome and when are they used? What are the advantages and disadvantages?
A 2D scaled physical anthropometric model based on a specific percentile human forms are called ergonomes. The ergonomes have been scaled from data taken from specific percentile ranges to form a standard human form. Ergonomes are used with drawings of the same scale as the model to consider the relationship between the size of an object and people. They are used with 2D drawings, mainly for orthographic drawings and also modelling to view field of reach, field of vision, etc.
What is a manikin? What are the advantages and disadvantages?
A manikin is an anatomical 3D model of the human body. A jointed model of the human body used by artists, especially to demonstrate the arrangement of drapery. They are useful for assessing the relationship of body parts to spatial arrangements represented by a 3D model, for example, a chair to a desk. Full scale manikins are generally more expensive than ergonomes and they give a better representation of the overall ergonomics in the design context (such as crash test dummies).
List other examples of a design context where an ergonome would be more suited than a Manikin
Percentile Range
That proportion of a population with a dimension at or less than a given value. For a given demographic (gender, race, age), the 50th percentile is the average.
You are expected to be able to:
interpret percentile tables in order to calculate dimensions related to a product
consider the 5th, 50th and 95th percentiles in particular
interpret percentile tables based on different national and international populations, gender and age.
Methods of extremes:
Sometimes you can't accommodate all your users because there are conflicting solutions to your design. In this case, you will have to make a judgment about what is the most important feature. You must never compromise safety though, and if there is a real risk of injury, you may have to use more extreme percentiles “methods of extremes” (2.5th to 97.5th) to make sure that everyone is protected (not just 95% of people).
Class Discussion:
Explain the bell curve distribution of anthropometric data.
Discuss the advantages and disadvantages.
Describe a design context where the 5th–95th percentile range has been used.
Describe a design context where the 5th percentile has been used.
Describe a design context where the 50th percentile has been used.
Explain the limitations of using the 50th percentile as a means of designing for the “average” person.
Outline why different percentile ranges are used in car design.
Clearance and Reach
Clearance is the physical space between two objects (the minimum distance required between user and object).
An example is to enable the user group into or through an area. This is especially important when designing emergency exits and safety hatches or the clearance from a chair you are sitting on to the lower part of a table.
Clearance examples:
The minimum vertical space between the floor and an overhead obstruction must allow for the tallest user plus their footwear and headgear.
The minimum horizontal space between two obstructions must allow for the widest user plus room for movement and equipment.
A hazard must be beyond the reach of the user with the longest arm, if there is no room to bend.
Grille openings in front of a hazard must not allow reach to the hazard by the user with the longest or thinnest finger.
Reach is the range that a person can stretch to touch or grasp an object from a specified position. Is also known as the workspace envelope.
A 'workspace envelope' is a 3-dimensional space within which you carry out physical work activities when you are at a fixed location. Workspace envelopes should be designed for the 5th percentile of the user population, which means that 95% of users will be able to reach everything placed within the envelope.
Adjustability and Range of Sizes
Why does a designer need to consider adjustability when designing seating?
The ability of a product to be changed in size, commonly used to increase the range of percentiles that a product is appropriate for.
Certain products tend to be available in different sizes or with adjustability built in as there really is no ‘one size fits all’.
E.g. Ironing tables can be adjusted to allow for people of a different height to use comfortably. This has an effect on the design of the legs, as this is how the board is adjusted in height.
Explain what is meant by the range of sizes versus adjustability
A selection of sizes a product is made in that caters for the majority of a market.
Clothing comes in a range of sizes. For manufacturers to make clothing fit every individual variance would not be economically possible, thus it tends to come in a range of sizes based on percentile ranges.
Children’s car seats are adjustable to allow for a range of sizes and a growing child.
Why do climbing helmets come in a range of sizes and what aspect of them make them adjustable?
Outline the clearance and reach factors that need to be considered in the design and layout of a driver’s seat in a car interior.
What might be some issues for different percentile groups of users in the interior of a car as the driver?
Explain how bicycles come in a range of sizes as shown below and outline the features that are adjustable. Use sketches / additional annotation if necessary.
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