Meeting the needs of older and disabled consumers
Guidelines for product design and testing
(view report contents)
DESIGN PRINCIPLES
In this section we give general advice on what should be taken into
account to make products more easily used by older people and people with
disabilities - so that they are easier to use by as many people as possible.
Seven Principles of Design for All : from
The Center for Universal Design
(see Contacts - Other Useful Web sites)
Practical Product Principles : an overview
of the points raised by RICA’s work which need to be considered for
mainstream products to be more easily accessible
Human Factor Categories : information on the
implications of impairments.
For checklists for 10 mainstream products go to
SEVEN PRINCIPLES OF DESIGN FOR ALL
The Center for Universal Design at North Carolina State University in
USA (see Contacts - Other Useful Web sites)
has developed the following broad principles.
1 Equitable use: the design must be useful and marketable to any group
of users - avoiding segregation or stigmatisation of any users.
2 Flexible in use: the design must accommodate a wide range of individual
preferences and abilities.
3 Simple and intuitive use: the design must be easy to use and understand,
regardless of the user's experience, knowledge, skills or concentration
level.
4 Perceivable information: the design must communicate necessary information
effectively to the user, regardless of ambient conditions or the user's
sensory abilities.
5 Tolerance for error: the design must minimise hazards and the adverse
consequences of accidental or unintended actions.
6 Low physical effort: the design must be usable efficiently and comfortably
and with minimum fatigue.
7 Size and space for approach and use: appropriate size and space must
be provided for approach, reach, manipulation and use, regardless of the
user's body size, posture, or mobility.
PRACTICAL PRODUCT PRINCIPLES
controls
easy to reach: without the need to bend or stretch
large enough to grip easily: small fiddly controls put strain on the joints
used in bending fingers and hands
non-slippery surface: the greater the friction of the surface, the less
force is needed to retain the grip
protruding or raised rather than recessed: easier to locate by touch,
and open space around a protruding control allows it to be operated by
swollen and inflexible fingers, or the side of a very weak or painful
hand; recessed controls provide limited space for fingers only, requiring
a specific grip
requiring light pressure to operate: this decreases the pressure required
from the user's fingers
avoid controls requiring dual action, such as push and twist: they require
continued pressure and twisting at the wrist, painful or impossible for
some people
well spaced rather than cramped or close together: provide enough space
around each control for swollen fingers or a hand with tremor
use some different shapes and sizes: so different controls can be identified
by touch
large clear labelling: use strong colours that contrast against the background
colour
tactile markings: need to be easy to locate and feel, to guide partially
sighted and blind people
provide essential information in different modes: pictorial, tactile,
lights and sounds
stability
must not tip over easily
effective anti-slip bases: particularly helpful for one-handed use
accessories
easy action to connect and disconnect: without the need for precision
or strength
avoid fiddly parts: awkward to set up
separate storage as an alternative: to reduce the weight of a portable
product
cleaning
avoid unnecessary markings: they trap dust and debris and make cleaning
difficult
avoid sharp edges: uncomfortable or even painful to touch or grip
portability
no heavier than necessary to lift
good holding places or carrying handle: well placed, comfortable, space
for two hands
good balance and shape: so that it does not strain joints, nor swing into
the person carrying it
instructions
clear, straightforward layout
clear, straightforward type face
large type size: 14 point where possible, not below 10 point, and good
space between the lines
strong colour print on a light background
matt paper or with a slight sheen: glossy paper reflects light and is
more to difficult to read from
offer alternative formats: large print (14 point minimum), Braille and
audio tape
HUMAN FACTOR CATEGORIES
mobility
balance
muscle strength
dexterity
vision
hearing
cognition
Brief information follows on the broad categories of impairment that should
be taken into account in product design. The design for all approach necessarily
addresses this range of needs. In older age people are more likely to
have multiple impairments - for example some hearing, sight and physical
strength loss are all typical.
Mobility
Difficulty in walking can be caused by foot, leg, hip or back problems.
Many people can walk only a short distance and many rely on a walking
aid such as a stick. Speed of movement is also affected. Bending over
or down to reach or pick up something will be difficult, so the height
of any task will be important. Adjustable heights are helpful to people
with walking difficulties. They are likely to choose to sit at a task
which others will carry out standing.
The height of any object or task will be particularly important to people
who cannot walk at all and use a wheelchair. Reaching low will be difficult
and can unbalance their position. Items above a certain height will be
unreachable. Some wheelchair users have other disabilities, for example
in their upper body which will further restrict their reach.
Whether people are unable to walk or walk with difficulty, they are likely
to have problems bending, reaching, lifting and turning.
Balance
Difficulty in maintaining equilibrium can have a physical cause eg lack
of strength in the lower body, and a sensory cause eg difficulty in processing
visual information. Older people are more likely to experience dizziness.
Firm and safe supports should be provided where hands will easily find
them, and the need for stretching should be avoided. In designing products
and layouts, attention should be paid to preventing trip hazards.
Dexterity
Arthritis is a common cause of poor dexterity, creating pain in the joints
and limited movement and weakness in the arms and hands. In handling products
people cannot get a firm grip, have limited strength to pull or push,
and they find precise finger movements impossible or painful. Actions
that require force or a tight hold put pressure on the fingers and strain
on the joints. The discomfort and pain are prolonged if continued force
is needed. Double actions, such as push and twist, are particularly difficult
for people with poor dexterity. The use of one hand and arm can be more
restricted than the other, so people may use just their stronger hand
to carry out tasks. Those with paralysis on one side will do everything
one handed.
Vision
There is a continuum of visual impairment. Short- and long-sightedness
are very common and both usually corrected by spectacles. There are a
number of more severe impairments which prevent people seeing images clearly
and fully. They include a reduced field of vision, including tunnel vision,
difficulty in perceiving depth, in distinguishing similar colours from
each other, difficulty focusing and seeing an interrupted image, such
as spots before the eyes. At the extreme is blindness. Some blind people
can distinguish light and shape, others have no awareness of light. People
who are blind depend on tactile information on products. Few use braille
but all will use raised markings and shapes to feel their way round an
item.
The ability to discriminate detail and to discriminate differences between
levels of contrast both decline with age. Older people need more light
to distinguish objects than younger people. Difficulty reading small print
is common after the age of around 50.
People who use visual information, whatever their level of impairment,
are helped by large print and good colour contrast, and matt paper or
surfaces: avoid reflecting surfaces and dazzle. In handling products people
with poor sight have difficulty with visual displays, seeing markings
and labelling and any assembly that involves small parts. Printed instructions
are a problem. Information should be as short and simple as possible,
the layout straightforward, and as well as large print and strong colour
contrast, sans-serif typefaces are generally easier to see.
Hearing
People of any age can be hearing impaired but loss of hearing is part
of the natural ageing process. The high frequencies or tones are usually
lost first. People with a moderate hearing impairment, who are hard of
hearing, have difficulty hearing conversation and specific auditory information,
particularly against background noise. People with severe impairment,
deaf people, cannot use hearing for communication.
Product design should use a combination of audible with other signals,
such as visual. Any audible elements should be adjustable where possible,
so that both volume and tone can be adjusted to suit the user.
Cognition
Cognitive impairment affects the ability to take in information and attend
to it, to learn new things, to make decisions and to solve problems. The
ability to concentrate declines in older age, so older people have difficulty
keeping their attention focused on a task. The increased use of medication
can cause drowsiness.
People with cognitive impairment are helped by simple displays and the
use of obvious sequences and patterns. Information is more difficult to
remember if it has no clear structure. Printed text should be kept to
a minimum, with steps and choices clearly illustrated graphically. People
should not be expected to remember complex operations.
Report Contents
Introduction
Why design for all is important
Using
research to identify needs - the basic toolkit
Product group checklists
- washing machines
- tumble driers
- vacuum cleaners
- microwave ovens
- electric irons
- electric kettles
- toasters
- food preparation machines
- telephones
- cars
The practical principles of design for all
What can be done to raise awareness
Useful contacts
