In Malaysia , home is second to road as a place
for injury morbidity and mortality. There were 13,401
home injury cases and of which 44 cases (0.3%) were
Products such as floor and flooring surface, stairs,
furniture, toys and baby walkers had been identified
as factors that could contribute to injury.
Source: Hasni, H., Junainah S. and Jamaliah J., 2003, Epidemiology of
Home Injury in Malaysia
PRODUCTS ARE UNSAFE TO USE
Most product safety problems
arise from improper product use
rather than product defects.
THOMAS A. HUNTER
SAFETY IS FREEDOM FROM
DANGER, INJURY OR DAMAGE
Physical injury or damage
to the health of people or
damage to property or the
[ISO/IEC Guide 51:1999, definition 3.3]
THERE ARE 2 CAUSES OF
ERRORS = INJURY, DEATH & DAMAGE
HUMAN ERROR IS THE FAILURE
OF PLANNED ACTIONS TO
ACHIEVED THEIR DESIRED
It is suggest that human error is a
primary cause of 60-90% major
basic types of
Involve routine tasks in familiar
May cause by inattention or
Two categories – slips and
Failure of execution of planned
tasks i.e. ‘action-not asplanned’.
May be due to distraction from
task or preoccupation with other
Slips – examples
Picking up the wrong
component from a mixed box.
Omitting a step or series of
steps from a task.
Performing the action in the
wrong direction (e.g. turning a
control knob to the right rather
than the left.
Failures to carry out an action
due to forgetfulness (memory
Can be reduced by minimising
distractions and interruptions to
tasks and by providing effective
Do the wrong thing believing it
to be right.
Two types of mistakes – rulebased and knowledge-based.
Occur when our behaviour is
based on remembered rules or
It is called rule-based because
we apply rules of the kind: if
(this situation) then do (these
May occur when we have to
think our way through a novel
situation for which we do not
have a procedure or “rule”.
Make wrong judgement due to
insufficient knowledge or
experience (lack of expertise).
Some useful guidelines:
Designer must avoid any design which expects
or requires individual/users to:
Exceed their physical strength.
Perform too many functions simultaneously.
Detect and process more information than is possible.
Perform meticulous task under difficult environmental
Work at peak performance for long periods.
Work with tools in cramped spaces, etc.
Figure 1 : Labelling around the
programme control is difficult to
Figure 2 : Protruding dials are
easy to grip and the labelling
easy to see
Figure 3 : Interface design of microwave ovens. Design A combines
simplicity and functionality. Design B and C leads to confusion and
many user errors
Figure 4 : Switches which are identical in shape and arranged in onedimensional row make it more possible to commit error. There are two
solutions: place a visual display with the switches (A) or arrange the
switches to match the room layout (B)
Figure 5 : Which control goes to
Figure 6 : Full natural mapping of controls and burners
Figure 7 : A typical power
plant control room
Figure 8 : Make the controls look and
operators in a nuclear power plant tried to
over come the problem similar-looking
knobs by placing beer-keg handles over
Make sure that the user can
figure out what to do!
Make sure that the user can tell
what is going on!
Ergonomics and Safety in Consumer Product Design, B.
Norris and J.R. Wilson in Human Factors in Product
Design: Current Practice and Future Trends. (2001)
Patrick W. Jordan and William S. Green
Rapid Alert System for non-food products posing a
serious risk (RAPEX).
Designing safety into products, Beverley Norris and John
MS ISO 12100:2012 Safety of machinery - General
principles for design - Risk assessment and risk