1. The document discusses product safety and design for safety. It defines key safety terms like hazard, risk, harm and discusses causes of unsafe products such as human errors and violations. 2. Safe product design can be achieved through intrinsic, ergonomic and usable safety approaches. Products should be evaluated based on their features, how users will interact with it, environmental factors and all stages of product life cycle. 3. Guidelines for safe design include avoiding designs that exceed users' capabilities and providing clear, intuitive user interfaces and controls. Examples show better and worse control room and appliance designs.

1. DESIGN FOR SAFETY
NURUL IKHMAR IBRAHIM
SCHOOL OF MANUFACTURING ENGINEERING
UNIMAP

2. Course Outcome
CO 3: Ability to analyze and
evaluate products’ safety
using suitable methods.

3. Today’s topic
Safety Definition
Safety Problems &
Human Failures
Designing Safe
Products

4. 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
fatal.
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
SAFETY DEFINITION

5. WHY?
PRODUCTS ARE UNSAFE TO USE
SAFETY DEFINITION

6. Most product safety problems
arise from improper product use
rather than product defects.
THOMAS A. HUNTER

7. SAFETY IS FREEDOM FROM
DANGER, INJURY OR DAMAGE

8. HARM
Physical injury or damage
to the health of people or
damage to property or the
environment.
[ISO/IEC Guide 51:1999, definition 3.3]
SAFETY DEFINITION

9. HAZARD
Potential source of harm.
[ISO/IEC Guide 51:1999, definition 3.5]
SAFETY DEFINITION

10. ERGONOMICS HAZARD
In terms of users’ mental &
physical capabilities, which
include:
1. Body dimension.
2. Strength & posture.
3. Frequency, duration &
intensity of task/work.
4. Information processing
(Human error)
5. Environmental factors
SAFETY DEFINITION

11. RISK
Combination of the
probability of occurrence of
harm and the severity of
that harm.
[ISO/IEC Guide 51:1999, definition 3.2]
SAFETY DEFINITION

12. DANGER
A combination of risk and
probable hazard
consequences.
SAFETY DEFINITION

13. Today’s topic
Safety Definition
Safety Problems &
Human Failures
Designing Safe
Products

14. INFLUENCES OF CONSUMER SAFETY
macro
SAFETY INFORMATION
Government
Standards
Industry
micro
PRODUCT
DESIGN
Conditions of use
Consumer behaviour
CONSUMER SAFETY

15. People can cause or contribute to
accidents – human failures.

16. THERE ARE 2 CAUSES OF
HUMAN FAILURES

17. THERE ARE 2 CAUSES OF
HUMAN FAILURES
VIOLATIONS +
ERRORS = INJURY, DEATH & DAMAGE

19. HUMAN ERROR IS THE FAILURE
OF PLANNED ACTIONS TO
ACHIEVED THEIR DESIRED
NEEDS

20. It is suggest that human error is a
primary cause of 60-90% major
accidents.

21. There are
2
basic types of
human error:
1.Skill-based error
2.Mistakes
HUMAN ERRORS

22. Skill-based error
 Involve routine tasks in familiar
situations.
 May cause by inattention or
over attention.
 Two categories – slips and
lapses
HUMAN ERRORS

23. Slips
 Failure of execution of planned
tasks i.e. ‘action-not asplanned’.
 May be due to distraction from
task or preoccupation with other
things.
SKILL-BASED ERROR

24. 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.
SKILL-BASED ERROR

25. Lapses
 Failures to carry out an action
due to forgetfulness (memory
failures).
 Can be reduced by minimising
distractions and interruptions to
tasks and by providing effective
reminders.
SKILL-BASED ERROR

26. Lapses – example
SKILL-BASED ERROR

27. Mistakes
 Do the wrong thing believing it
to be right.
 Two types of mistakes – rulebased and knowledge-based.
HUMAN ERRORS

28. Rule-based mistakes
 Occur when our behaviour is
based on remembered rules or
familiar procedures.
 It is called rule-based because
we apply rules of the kind: if
(this situation) then do (these
actions).
MISTAKES

29. Rule-based mistakes example
MISTAKES

30. Knowledge-based
mistakes
 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).
MISTAKES

31. Knowledge-based
mistakes - example
MISTAKES

32. VIOLATIONS ARE ANY
DELIBERATE DEVIATIONS FROM
RULES, PROCEDURES,
INSTRUCTIONS & REGULATIONS

33. There are
3
categories of
violations:
1.Routine
2.Situational
3.Exceptional
HUMAN ERRORS

34. Routine
 Breaking the rule or procedure
has become a normal way of
working within the work group.
VIOLATIONS

35. Routine - example
VIOLATIONS

36. Situational
 Breaking the rule is due to
pressures from the job such as
being under time pressure, the
right equipment not being
available, or even extreme
weather conditions.
VIOLATIONS

37. Situational – design features which increase
violation
VIOLATIONS

38. Situational - example
VIOLATIONS

39. Exceptional
 Rarely happen and only then
when something has gone
wrong.
VIOLATIONS

40. Exceptional - example
VIOLATIONS

41. Today’s topic
Safety Definition
Safety Problems &
Human Failures
Designing Safe
Products

42. SAFE PRODUCT DESIGN CAN BE
ACHIEVED VIA 3 COMBINED
APPROACHES

43. Intrinsic Safety
 Focused on immediate/initial
use.
 Minimizes direct injury from
device (e.g. sharps, burns)
DESIGNING FOR SAFETY

44. Ergonomic Safety
 Focused on repetitive and/or
long-term use.
 Minimizes
fatigue
and
cumulative injury effects (e.g.
carpal tunnel)
DESIGNING FOR SAFETY

45. Usable Safety
 Focused on full life-space of
product use.
 Minimizes opportunities for
incorrect use (e.g. overdose)
DESIGNING FOR SAFETY

46. SAFE PRODUCTS CAN BE
DESIGNED THROUGH ERGONOMICS
EVALUATION METHOD

47. What should you
evaluate?
#1
 The features of the product.
DESIGNING FOR SAFETY

48. What should you
evaluate?
#2
 The physical and psychological
characteristics of the user.
DESIGNING FOR SAFETY

49. What should you
evaluate?
#3
 How the product will be used,
associated with tasks and
activities.
DESIGNING FOR SAFETY

50. What should you
evaluate?
#4
 Environmental factors.
DESIGNING FOR SAFETY

51. The evaluation must consider
all stages of product’s
lifecycle.

52. A
FRAMEWORK
FOR
PRODUCT
EVALUATION
PROCESS

54. 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
conditions.
 Work at peak performance for long periods.
 Work with tools in cramped spaces, etc.

55. EXAMPLES OF EVERYDAY
PRODUCTS

56. Figure 1 : Labelling around the
programme control is difficult to
read
Figure 2 : Protruding dials are
easy to grip and the labelling
easy to see

57. A
B
C
Figure 3 : Interface design of microwave ovens. Design A combines
simplicity and functionality. Design B and C leads to confusion and
many user errors

58. A
B
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)

59. Figure 5 : Which control goes to
which burner?

60. Figure 6 : Full natural mapping of controls and burners

61. Figure 7 : A typical power
plant control room
Figure 8 : Make the controls look and
feel
different.
The
control-room
operators in a nuclear power plant tried to
over come the problem similar-looking
knobs by placing beer-keg handles over
them

62. Make sure that the user can
figure out what to do!

63. Make sure that the user can tell
what is going on!

65. References
 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).
http://ec.europa.eu/consumers/ipm/risk_assesment_guid
elines_non_food.pdf
 Designing safety into products, Beverley Norris and John
R. Wilson
http://person.hst.aau.dk/pm/ab/DSP.pdf

66. References
 MS ISO 12100:2012 Safety of machinery - General
principles for design - Risk assessment and risk
reduction