Effectiveness of Safety Measures in Maritime Operations Svein Kristiansen and Torkel Soma Norwegian University of Science and Technology Division of Marine Systems Design N-7491 Trondheim, Norway
Summary An approach for assessing the effect safety controls on the policy level is proposed, outlined and demonstrated with a limited set of empirical data. Focusing on impact accidents the probability of loss of navigational control may be taken as a safety level criteria. The paper describes how this criteria can be estimated on the basis of direct and basic causal factors in a fault tree like way. It is further proposed a way of expressing the effect of safety control areas on the probability of causal factors. The parameters in the model have been estimated on the basis of a Delphi type questionnaire study. Preliminary findings based on the model gives an indication of the potential effect of the ISM Code. An interesting observation is that the maximum risk reduction is already obtained around 50 % implementation of the code.
1
Introduction
The understanding of why maritime accidents happen and how they might be prevented is still not very well developed. This fact can partly be explained by the complexity of the accident itself and that it often involves a series of critical events and a multitude of causal factors. Even the cause as a concept, is a source of confusion in the sense that it might be defined and analyzed in different and often competing scientific perspectives. [Kristiansen, 1995] . The work towards higher safety is taken place on many arenas : Regulations, certification, technological innovations, training, human factors and quality management. This effort has given significant results but but there is still a considerable pressure on the industry dictated by such concerns as environmental protection. There has always been a certain conflict between commercial efficiency and safety. This very fact makes necessary that the resources available for safety is spent in the most cost-effective way. This might be obtained by applying cost-benefit analysis and probabilistic risk analysis. The key question here is to assess the effectiveness of potential safety measures. As already pointed out this raises certain problems related to the inadequate understanding of maritime accidents. With these reservations in mind this paper will outline an approach for estimating the effect of preventive measures within the framework of impact-accidents (collision and grounding).
2
Safety performance
The safety in international shipping has been a subject of increasing concern during this century. Major milestones in the work towards higher safety were the introduction of SOLAS, MARPOL, STCW and ISM codes of IMO. The average loss rate has decreased with an annual rate of 2.4 % [Lancaster, 1996]. This improvement has also been witnessed for navigational or impact related casualties such as collision and grounding. Although the collision rate has been moderate for a considerable period as can be seen from Figure 1, further improvement has been gained. The decrease in loss rate due to grounding has however been more distinct. In 50 years it has gone down from 3 to 0.6 losses/ship-year which represents a reduction with a factor of 5, which is dramatic.
0,014 Collision Wrecked
0,012
Total lost
0,008
0,006
0,004
0,002
95
93
19
19
89
91
19
87
19
85
19
19
81
83
19
19
77
79
19
75
19
73
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71
19
19
67
69
19
65
19
63
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61
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57
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55
19
19
51
53
19
49
19
47
19
19
43
45
19
41
19
39
19
19
37
0 19
Loss Ratio
0,01
Year
Figure 1 Loss ratio of world merchant fleet. Loss ratio : Total losses per 1000 ship-year (Source : Lloyd’s Register).
It is however a problem that the different segments of shipping show a significant variation in performance. Figure 2 gives an indication of the spread in loss rate within the world fleet. It appears that the performance varies with a factor of 10 between the best and the worst flag state fleets. It has been established that there is a correlation between accident rate and safety standard expressed in terms of deficiency rate and detention rate [Kristiansen & Olofsson, 1997] . See Figure 3. It can be concluded from this observation that there are still room for safety improvement in shipping, but that the effort will have greatest payoff when directed towards the lowest performing segments of the fleet. That is not least a fact when implementing the ISM Code.
14 12 10 8 6 4 2 0 Worst
Med.
Mean
North
Top
Figure 2 Loss rate for different segment of the world merchant fleet. Number of losses per 1000 shipyear. 1990 - 93. Data source : Lloyd’s Register. Worst : Group with highest loss rate; Med : Mediterranean Mean : Mean for world fleet; North : Northern Europe; Top : Group with lowest loss rate.
Detention & deficiency rate
70 60 50 40 30 20 10 0 0
2
4
6
8
10
Loss rate (1000 ship-years)
Figure 3 Loss rate versus detention and deficiency rate. Percentage of vessels inspected by Port State Control. Deficiency : Non-conformity. Detention : Vessel withheld due to seriousness of nonconformity.
3
ISM – Quality management in shipping
The regulation of safety in shipping has to a large degree been based on the principle of prescription where the industry is given rules and regulations to follow. For example, the provisions of SOLAS 1974, MARPOL 73/78, Collision Regulations, Load Line Convention and STCW 78/95 provide the basis of the external regulatory framework. A more ambitious stage is presently entered by the creation of a culture of self-regulation of safety, where regulation goes beyond the setting of externally imposed compliance criteria. The new approach concentrates on the role of internal management and organisation for safety and encourages individual companies to set there own targets for safety performance. Self-regulation also emphasises the need for every company and individual to be responsible for the actions taken to improve safety, rather than seeing them imposed from outside. This requires the development of company specific, and in the case of shipping, vessel specific, safety management systems (SMS). Another important principle is that safety problems are addressed by those who are directly involved and affected by the operations and potential unwanted consequences. The ISM Code itself is a fairly short document of about 9 pages [IMO, 1994 &1995]. The main purpose with ISM is to demand that individual ship operators create a safety management system that works. The Code does not prescribe in detail how the company should undertake this, but just states that some main areas of measures have to be addressed. The philosophy behind ISM is commitment from the top, verification of positive attitudes and competence, clear placement of responsibility and quality control of work. IMO has stated following objectives for the adoption of a management system : 1. 2. 3. 4. 5.
to provide for safe practices in ship operation and a safe working environment to establish safeguards against all identified risks to continuously improve the safety management skills of personnel ashore aboard, including preparing for emergencies related both to safety environmental protection
This clearly shows that ISM has a relation to existing or traditional approaches such as technical solutions, training, emergency preparedness and risk analysis. The ISM Code is specifying certain requirements for a safety management system (SMS) of the operating Company. In order to have the SMS to work, certain distinct functions have to be in place. The different chapters in the ISM Code cover these elements or roles of the system. The objective and policy element states how the safety and environmental protection is approached in the SMS. The requirements-element both points to applicable rules and regulations and the functions that constitutes the system. The core of the SMS is made up of certain controls which are defined in terms of [Kristiansen & Olofsson, 1997] : • • • •
responsibility and authority supply of resources and support procedures for checking of competence and operational readiness, training, shipboard operations minimum standards of the maintenance system
2. SA FETY & ENV IRONMENTA L PROTECTION POLICY
RELEV A NT IMO CONV ENTIONS
SAFETY POLICY REQUIREMENTS
LEGISLATIVE REQUIREMENTS
THE DEVELOPMENT OF CONTROLS HAZARD IDENTIFICATION & RISK ASSESSMENT 1.2.2.2 ESTA BLISH SA FEGUARDS 10.3 IDENTIFY CRITICA L SY STEMS
3. RESPONSIBILITIES & A UTHORITY 4. DESIGNA TED PERSONS 6. RESOURCES & PERSONNEL 7. PLANS FOR OPERA TIONS 8. EMERGENCY PREPA REDNESS 10 MA INTENA NCE
SAFETY MANAGEMENT SYSTEM (SMS) 11. DOCUMENTA TION
THE IMPLEMENTATION OF CONTROLS 5. MA STER'S RESPONSIBILITY & A UTHORITY
OPERATIONS
PERIODIC SYSTEM REVIEW 12. INTERNA L COMPA NY V ERIFICA TION, REV IEW A ND EV ALUA TION
Figure 4 ISM - Functional interrelationships
MONITORING THE SM SYSTEM
PROACTIVELY
REACTIVELY
12. THE ISM AUDIT
9. REPORTS & A NA LY SIS OF A CCIDENTS ETC
Chapter 11 of ISM states that the SMS shall be adequately documented and may be seen as a product of the establishment of controls. Another key feature of the ISM concept is the definition of a monitoring function, which is based on audits and reporting of events. The auditing shall ensure that errors and shortcoming in the SMS are corrected and that the system is updated in view of new requirements and conditions. The auditing and event reporting will also address system errors and hazards directly and this may lead to corrective actions in terms of modified systems and improved human competence. Chapter 13 mainly states that the company should have a certificate of approval that states that its SMS is in accordance with the intention and specific requirements of the ISM Code. This item is therefore not relevant for the material content of the SMS and will not be addressed further in this project. The interaction of the different elements in the ISM Code is outlined in Figure 4.
4
Risk assessment model
A well known and often applied approach for estimating the frequency for impact related accidents is to take the product of two probabilities, namely the probability of loss of navigational control and the conditional probability of being on a critical course [Kristiansen,1983]. This can be expressed as follows : P(C) = P(K) • P(S|K) where: P(C) = Probability of accident due to loss of navigational control P(K) = Probability of loss of navigational control P(S|K) = Conditionally probability of colliding, grounding or stranding if navigational control is lost
The conditional probability of a critical course assumes that the vessel maintains a fixed straight course and not giving way to fairway obstructions and maritime traffic. This means that it is dependent of geometrical factors such as the dimensions of shoals and approaching vessels. This element of the assessment model is represented by the left hand side in the structural diagram of the model given in Figure 5. The model can therefore be applied for specific routes and traffic scenarios [Soma, 1998]. The probability of loss of control may be seen as the cut-set or union of all potential failures and errors that might take place onboard the vessel. It involves technical failure, operator error and extreme environmental effects. These so called Direct Causes are organized in 9 groups and 29 unwanted events. They are related in a fault tree that for simplicity reasons only has “or-gates” : P(K) = Ui=29 [P(DCi)] where : P(DCi) = probability of the i’th direct cause It is acknowledged that most accidents are a function of more than one critical event but the lack of data dictates this simplification. A more detailed description of the direct causes are given in the Appendix. It is generally accepted today that the unwanted events should be seen in the light of the available resources within the managing company : Personnel, organization and management, and job
factors. Firstly, the individuals may have mental or physical limitations and inadequate competence and skills. The organization may in the same way be ridden by different “health problems” and have inadequate management to ensure quality in the decisions. Thirdly, it is well established that physical conditions and the ergonomics of the work place are vital for a safe operation. These factors are termed Basic Causes in the model and consist of 14 factors which are defined in greater detail in the Appendix.
Casualty Grounding & Collision
Loss of navigational control
V es s el on haz ardous c ourse
Fairw ay
Marine traf f ic
RISK FA CTORS
V is ibility Direc t Caus e Failure or error onboard v es sel 9 DC groups - 29 DC
Nav igation
V ess el control
Basic Caus e Cas ualty induc ing f ac tors 3 BC groups - 14 BC
Indiv iduals
Organis ation
Work plac e
Ris k c ontrol areas 5 CA
Technic al / Pers onnel/ Operations/ Saf ety mngt/ Top level mngt/Inf rastructure
Saf ety meas ure : ISM
Figure 5 Assesment model - structure of functional modules
Numerically each direct cause, DCi , can be expressed by a weighted sum of the probabilities of the basic causes : P(DCi) = ∑j = 14 [ P(BCj) • wij ] where : wij = weight of BCj with respect to DCi The last modeling level is the set of Risk Control Factors which express the broad areas for safety improvement : Technical, Personnel, Operational, Safety Management, Top level management and Infrastructure. The nature of these areas are described by keywords in the Appendix. The control factor represents a conceptual problem in a sense that it can be not be defined exhaustively because new innovations are seen continuously. It is in other words an unbounded set of known and potential safety measures. Each control area have a certain impact on the basic causes. The model expresses this impact by stating the relative reduction of the probability of a basic cause given a 100 % implementation of the control area in question. The modeling approach will be outlined further in the following chapter.
5
Model estimation
As pointed out in the introduction there exists little systematic data on the frequency of causal factors. Alternative research designs for estimation of the frequencies were assessed [Soma, 1998]. It was decided to do a Delphi type of questionnaire survey with maritime college students. The first part of the survey was to estimate the frequencies of the direct and basic causes. An approach using pairwise comparison was applied. This implies that the relative importance of causal factors are assessed two-by-two. The fact that the number of combination of factors were quite large required that certain simplifications were made. Following approach were taken : • • •
Exercise 1 : Ranking of direct causes within each direct cause group Exercise 2 : Ranking of the effect of basic cause groups on each direct cause Exercise 3 : Ranking of basic causes within each basic cause group
The design of the questionnaires for these exercises are shown in Table 1 to Table 3. The respondents were asked to assess the relative importance of pairs of causal factors on a bipolar scale. The scale has 7 values which gives following alternatives to the respondent : Equal importance, slightly higher, higher and much higher. Numerically the ranking has been given following numbers : 1, 3, 5 and 7. Each set of coded answers may be processed in order to give an absolute ranking of all factors within each group. This process involves certain matrix and normalization operations. One technicality is that the bipolar scale has to be transformed to an unipolar scale as shown in Table 4. This can be explained by following statement : If A is 3 times as important as B, it follows that the importance of B is 1/3 of that of A. In order to compute statistical parameters like mean and variance for the whole set of answers, a so called arithmetic scale also had to be introduced. As seen from Table 4 this ranged from 1 to 7 in equal steps.
Table 1 Questionnaire for Exercise 1. Ranking within Direct cause group. Case example : Group “Incapacitation of OOW”
Direct cause OOW absent, absorbed OOW absent, absorbed OOW inattention
Much higher
Higher
Slightly higher
Equal
Slightly higher
Higher
Much higher
7
5
3
1
3
5
7
Direct cause OOW inattention Too high work load Too high work load
Table 2 Questionnaire for Exercise 2 : Effect of Basic cause group on Direct cause. Case example : Incapacitation of OOW.
Basic cause group Personnel factors Personnel factors Job factors
Much higher
Higher
Slightly higher
Equal
Slightly higher
Higher
Much higher
7
5
3
1
3
5
7
Basic cause group Job factors Org. and management Org. and management
Table 3 Questionnaire for Exercise 3 : Ranking of Basic causes within Group. Case example : Personal factors.
Basic cause Lack of skill Lack of skill Lack of skill Lack of skill Inadeq. physical capability Inadeq. physical capability Inadeq. physical capability Lack of motivation Lack of motivation Lack of knowledge
Much higher
Higher
Slightly higher
Equal
Slightly higher
Higher
Much higher
7
5
3
1
3
5
7
Basic cause Inadeq. physical capability Lack of motivation Lack of knowledge Inadeq. mental capability Lack of motivation Lack of knowledge Inadeq. mental capability Lack of motivation Lack of knowledge Inadeq. mental capability
Table 4 Transformation of pairwise comparison scales
Bipolar scale Unipolar scale Arithmetic scale
7 1/7 1
5 1/5 2
3 1/3 3
1 1 4
3 3 5
5 5 6
7 7 7
The two last exercises in the questionnaire survey was to assess the effectiveness of preventive measures on the basic causes. •
Exercise 4a : Assess the effect of each control area on each basic cause.
The importance is expressed with a scale ranging from “None effect” to “Complete effect” as illustrated by the example in Table 5. This scale corresponds to a reduction of the probability of the basic cause in the range of 0 % to 95 %. The questionnaire form in Table 5 was presented for each of the 6 control areas.
Table 5 Questionnaire for Exercise 4a : Effect of Control area on Basic causes. Case : Technical control area
Subjective effect Reduction in %
None
Moderate
Considerbl
Strong
Complete
0
20
50
80
95
Basic Cause
BC Group Lack of skill
Personnel factors
Inadeq physical & physiological capability Lack of motivation Lack of knowledge Inadequate mental or physiological state Inadequate tools and equipment
Job factors
Inadequate environmental conditions Physical stress LTA ergonomic conditions Lack of supervision
Organisation & management factors
Inadequate organisational values/ climate Inadequate cultural and social factors Inadeq management and communication Inadequate manning and job content
Table 6 Questionnaire for Exercise 4b : Importance of ISM within Control area. Case : Technical control.
Control Area :
Total of Technical Specific Improved Human-Machine
Technical
Technical Specific Measures in the ISM - Objective - Establish Safeguards against all
General
Improved Reliability and Improved performance of existing
Maintenance of Ship
-
Instrumentatio Monitorin Automation
Maintenance according to relevant rules at a Inspection held at appropriate Reporting of nonAppropriate actions are Records of these actions are Critical equipment is identified and its reliability
Improved work place
If the left group cover a 100 % of potential safety improvement due to Technical improvement , how would YOU quantify the potential of the Code. TECHNICAL Control 100 %
ISM safety potential in Technical 0%
10 %
20 % 30 % 40 % 50 % 60 % 70 % 80 % 90 % 100 %
The final set of questions relate to the ultimate objective of the study namely the effect of the ISM Code and is formulated as follows : •
Exercise 4b : Given that the potential effect of a given Control area is set to 100 %, how much will be attained by the implementation of the ISM Code ?
The approach is illustrated in Table 6 which addresses the effect of ISM on the Technical control area. The left hand side of the screen presents the main technical means in keyword form, whereas the right hand side highlights the key technical topics mentioned in the ISM Code. The respondent is asked to rate the importance of ISM on a scale from 0 % to 100 %.
6
Results of study
The questionnaire study was performed on 3 groups of students at : • • •
Maritime Master’s students at NTNU Maritime students at Ålesund Maritime College Maritime students at Vestfold Maritime College
The study was in principle undertaken as a Delphi study in the following manner : 1. 2. 3. 4. 5. 6.
Presentation of objective, questionnaire forms and supporting information. Filling out of forms by respondents Processing of results Discussion of results in a plenary session with the students Revised filling out of the forms Processing of second set of results
For practical reasons and from experienced gained the 3 studies were not performed in an identical manner. They differed somewhat with respect to ordering of questions, use of written and oral information, and individual (take home) and plenary sessions for filling out. The students had also differing background and study programs. The students at NTNU had already completed the College level. The knowledge and experience with the ISM Code were also slightly different for the groups. 2
Vestfold
Ålesund
Trondheim
Session
Table 7 Variance in answers : S for scores. Computations are based on arithmetic scales. Exercise Characteristics Variables Respondents 2 First session – average s 2 Second session – average s 2 Truncated – average s Respondents 2 First session – average s 2 Second session – average s 2 Truncated – average s Respondents 2 First session – average s 2 Second session – average s 2 Truncated – average s
1
2
3
4a
4b
38 8 2.24 1.06 0.71 7 1.16 0.57 0.34 42 1.93 1.62 1.31
26 8 1.97 1.18 0.68 8 1.22 0.75 0.47 42 1.90 1.68 1.33
27 8 1.93 1.45 0.83 7 1.37 0.62 0.41 43 1.49 1.32 1.02
84 9 0.91 0.50 0.21 7 1.07 0.30 0.17 43 0.87 0.73 0.58
6 9 5.35 3.30 1.85 7 9.25 1.74 0.97 42 5.95 4.56 3.57
An analysis of the variation in responses within each exercise are summarized in Table 7. Firstly, it can be observed that it was major differences between the 3 groups with respect the average variance. Exercise 4a which addressed the potential effect of control areas on basic causes, showed least disagreement. The potential effect of ISM (4b) showed on other side considerable disagreement. The three first sets of answers relating to the frequency of causes also showed some variation, a little more than for exercise 4a but quite less than for 4b. The obtained results for the frequencies of causal factors are summarized in Table 8. For readability the frequencies are expressed in a relative mode. It can be seen that the major Direct causal groups are “Incompetence of OOW” (46 %) and “Incapacitation of OOW” (25 %). Within “Incompetence of OOW” following weight are put on the basic causes: “Personnel factors” are given higher weight (50 %) than “Organization & management” (33 %) and “Job factors” (17 %). For “Incapacitation of OOW” the picture is quite different in that “Personnel” and “Job” are set equal (39 %) and higher than “Org. & Man.” (21 %). The dominating trait of this part of the study was the weight put on personnel or individual factors. This can be seen in at least two alternative perspectives : The present dominating view to put strong weight on inadequate working conditions is overrated; or that the survey conveys the traditional view to put the liability on the individual.
Table 8 Relative frequencies of Direct and Basic causes Groups of Basic Causes Direct Causes Absent Inattention
Too high Work load LTA Bridge Equipment
12,6 % 55,6 % 29,8 % 31,7 % 11,8 % 16,4 %
LTA Radar Equipment
33,8 % 29,8 %
Chart not updated
33,5 %
LTA Bridge Equipment 4,0 % Incompetence of OOW 46,0 %
39,6 % 17,4 %
27,9 %
19,8 %
9,0 %
10,6 % 13,1 % 33,4 %
6,5 %
3,9 %
3,0 %
4,2 % 41,1 %
5,9 %
4,2 %
7,4 %
17,4 %
21,7 %
23,7 %
22,9 %
27,0 %
33,5 %
16,5 %
18,2 %
14,1 %
20,0 %
27,9 %
19,8 %
1,9 %
4,4 %
5,5 %
6,0 %
7,6 %
9,0 %
11,2 %
5,5 %
7,5 %
5,8 %
8,2 %
11,5 %
8,1 %
7,4 %
17,4 %
21,7 %
23,7 %
22,9 %
27,0 %
33,5 %
16,5 %
18,2 %
14,1 %
20,0 %
27,9 %
19,8 %
3,7 %
8,8 %
10,9 %
11,9 %
3,8 %
4,5 %
5,6 %
2,7 %
6,0 %
4,7 %
6,6 %
9,2 %
6,6 %
7,4 %
17,4 %
21,7 %
23,7 %
22,9 %
27,0 %
33,5 %
16,5 %
18,2 %
14,1 %
20,0 %
27,9 %
19,8 %
11,9 %
3,0 %
7,0 %
8,7 %
9,5 %
5,2 %
6,2 %
7,6 %
3,8 %
6,8 %
5,3 %
7,5 %
10,4 %
7,4 %
Failure of Control System 55,9 % Failure of Rudder / Hydr. 33,5 % 29,8 %
7,4 %
46,6 % 17,4 %
21,7 %
23,7 %
22,9 %
28,1 % 27,0 % 33,5 %
16,5 %
18,2 %
14,1 %
25,2 % 20,0 %
27,9 %
19,8 %
10,6 % 13,9 %
3,5 %
8,1 %
10,1 %
11,1 %
6,4 %
7,6 %
4,7 %
4,6 %
3,6 %
5,0 %
7,0 %
5,0 %
9,7 % 7,6 % 6,6 %
LTA Trip Plan
8,4 %
LTA Lookout an plotting
30,5 %
Alt. Equip. not used
14,5 % 15,0 %
No double checking
23,0 %
Failure of Anchor
40,9 %
Incompetent Inadequate Operation Control Too High Speed 10,0 % LTA Ship Handling
21,1 %
External Extreme Wind, Current Factors Shallow water eff. 9,0 % Manoeuvring Course Unstable 1,0 % Too large turning Radius
75,4 %
18,2 %
14,1 %
33,1 %
22,8 %
57,1 %
9,4 %
37,3 %
21,4 %
21,5 %
45,4 % 29,8 %
7,4 %
17,4 %
21,7 %
23,7 %
22,9 %
27,0 %
33,5 %
16,5 %
18,2 %
14,1 %
20,0 %
27,9 %
19,8 %
33,4 % 17,0 %
4,2 %
9,9 %
12,4 %
13,5 %
4,9 %
5,8 %
7,2 %
3,5 %
3,9 %
3,0 %
4,3 %
6,0 %
4,3 %
6,2 %
4,4 %
7,7 %
5,4 %
8,9 %
6,3 %
24,6 % 16,1 %
54,1 % 4,0 %
59,1 % 40,9 % 12,2 % 25,6 % 11,3 %
9,4 %
23,7 % 11,7 %
12,8 %
5,4 %
41,0 % 3,0 %
Inadequate Tug Operation 74,4 % Inadequate Tug Power
16,5 %
16,6 %
39,9 %
12,2 % 29,8 % 17,0 %
22,9 %
50,3 %
Inadequate Navig. Perfor. 23,6 % 29,8 %
29,9 %
23,7 %
21,2 % 20,0 %
9,4 %
No Depth Alarm
21,7 %
39,2 % 27,0 % 33,5 %
8,6 %
No Course Alarm
7,4 %
Organisation and Management Factors
Phys. Ergono Supervis Values / Cultural Commu Manning Stress mics ion Climate / Social nication
6,9 % 25,5 %
Few Visual Cues
Tug 1,0 %
Job Factors
2,9 %
LTA External LTA Support Pilot Support LTA Support VTMS 3,0 % LTA Markers & Buoys Technical Failure 1,0 %
Personnel Factors
Basic Causes Lack of Physical Motivati Knowled Mental Tools & Environ Skill capab. on ge State Equip ment
Incap acitati on of OOW 25,0 %
Groups of Direct Causes
7,1 % 6,6 %
7,9 %
3,9 %
4,0 %
3,1 %
31,5 % 8,9 %
9,7 %
7,2 %
38,1 % 2,8 %
6,4 %
22,2 %
8,5 %
10,6 %
5,2 %
5,0 %
3,9 %
30,0 % 8,3 %
9,0 %
6,9 %
8,1 %
10,1 %
4,4 % 27,5 % 5,5 % 31,9 %
5,0 %
5,8 %
4,5 %
6,4 %
Table 9 gives a summary of the results from Exercise 4a which assessed the effect of the 6 control areas on the basic causes. The table gives the percentage reduction of the probabilities for the basic causes for each control area. The results from the final exercise are summarized in Table 10. It can be seen that the ISM Code seems to contribute most to the “Personnel” and “Operations” areas by around 55 %. The lowest effect is found for “Infrastructure” whereas the other areas have an intermediate effect (45 % – 48 %). It can also for this exercise be questioned whether the small variation is correct. However, in this instance one may suspect that the objective of the exercise was too demanding : • •
The ISM Code has just been introduced and therefore difficult to assess. The Control areas are fairly broad and may therefore be difficult to relate to ISM.
Management
Job
Personnel
Table 9 Effect of Control areas on Basic causes. Reduction of probability in percent.
LTA Skill LTA Physical capability LTA Motivation LTA Knowledge LTA Mental capability Inadeq. Tools / Equipment Environmental conditions Physical Stress Ergonomic conditions LTA Supervision Org. climate Social Factors Management/Com Job Content
Tech
Pers
Op
SM
TM
I
34
54
45
47
35
25
20 34 34 18 39 35 29 33 25 24 22 34 29
30 39 59 32 26 25 37 22 33 27 33 39 35
20 36 45 21 41 26 34 24 38 29 33 41 31
19 42 49 29 40 26 37 22 46 33 34 45 33
14 37 39 21 26 25 31 21 41 33 33 35 28
11 23 30 19 36 30 32 28 26 24 21 33 25
Table 10 Contribution of ISM Code to Control area.
1 2 3 4 5 6
Main control area Technical Personnel Operation Safety Management Top Level Management Infrastructure
44,6 48,3 53,7 55,6 48,1 38,1
7
Findings
The results of the questionnaire study were outlined in the preceding chapter. It was here described how each modeling level affect the one above as outlined in Figure 5 : ISM Code ⇒ Control area ⇒ Basic cause ⇒ Direct cause ⇒ Loss of navigational control By entering these results into the integrated assessment model we are in the position to estimate the effect of the ISM Code on the top event in the fault tree, namely “Loss of navigational control”.
Infrastructure 10 %
Technical 13 %
Top Level Managm. 15 %
Personnel 19 %
Safety Managm. 24 %
Operational 19 %
Figure 6 The relative effect of the measures within the ISM Code on “Loss of navigational control”. The measures are allocated to the main Control areas.
In Figure 6 there is a break down of the relative effect of the different components in the ISM Code assuming full implementation. It appears that the strongest effect is obtained in the area of “Safety management”. This reflects perhaps the fact that ISM in its very nature focuses the management of safety related functions. Next follows “Operations” and “Personnel” both areas that can been seen as so called “soft” solutions. These control areas are in contrast with “Technical” measures which traditionally has been given strongest emphasis in safety programs. It may be seen as a little surprising that “Top level management” was given relatively low weight. It has in the current debate been pointed out that top management has a key role if further progress shall be seen. On the other side it may more realistically underline that company policies and objectives have a certain limitation compared to the other control areas which reflect the more demanding implementation aspect of safety management. It may be interesting to study possible differences of what that can be obtained by ISM and what that can be obtained not restricted to that Code. This is illustrated in Figure 7 by comparing the profiles of the two policies. It basically reinforcing what we have stated already. Finally, the implementation aspect shall be commented. Figure 8 shows the reduction of the probability of the top event as function of the degree of implementation of ISM. It is interesting to observe that the model indicates the potential in terms of risk reduction is reached already at 54 % implementation.
1,40E-04
1,20E-04
1,00E-04
8,00E-05
6,00E-05
4,00E-05
2,00E-05
0,00E+00 Technical
Personnel
Operational
Safety Managm.
Top Level Managm.
Maximum reduction by implementation of ISM -code
Infrastructure
Potential reduction by implementation of all measures within Control
Figure 7 Reduction of the probability of “Loss of navigational control”
0,00035
0,0003
0,00025
0,0002
0,00015
0,0001
0,00005
0 0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
Grade of Implementation
Figure 8 Reduction of top event as function of degree of ISM implementation
1
Ship loss rate (/ 1000 ship-years)
25
20 LTI / SHIPLOSS = 7,5 LTI / SHIPLOSS = 4,8
15
LT / SHIPLOSS = 11,1
10
5
0 0
0,25
0,5
0,75
1
Degree of SMS implementation
Figure 9 Ship loss rate versus implementation of a Safety management system
This finding is supported by another study which was based on a different approach to the problem [Kristiansen & Olofsson, 1997]. As a general conclusion it can be stated that ISM and other safety management approaches will be subject to decreasing results as the degree of implementation approaches 50 %.
Acknowledgement The initial work on the estimation model was undertaken in a Master’s Thesis by Kalve [1997]. Further progress was done in the SAFECO project [Kristiansen & Olofsson 1997, Olofsson & Kristiansen 1998] as part of EU’s 4.th Framework Programme and co-sponsored by the Norwegian Shipowner’s Association, Vesta Insurance & UNI Insurance. The present model was developed in Master’s Thesis study by Soma [1998].
References IMO, 1994, International Safety Management Code for the Safe Operation of Ships and for Pollution Prevention. (ISM Code). International Maritime Organization, London. IMO, 1995, Guidelines on Implementation of the International Safety Management (ISM) Code by Administrations. Resolution A.788(19). 8 December 1995. International Maritime Organization, London. Kristiansen, S., 1983, Platform Collision Risk on the Norwegian Continental Shelf. IABSE Colloquium “Ship Collision with Bridges and Offshore Structures. Copenhagen. Kristiansen, S., 1995, An approach to systematic learning from accidents. IMAS ’95 : Management and Operation of Ships. London, 24 – 25 May. The Institute of Marine Engineers, London. Kristiansen, S. and M. Olofsson, 1997, Criteria for management. SAFECO Work package II.5.1. Marintek Report MT23-F97-0175/233509.00.02. Trondheim Lancaster, J., 1996, Engineering Catastrophes – Causes and effects of major accidents, Abington Publishing. Cambridge, UK. Olofsson, M. and S. Kristiansen, 1998, An assessment of the effects of management control. SAFECO Work package II.5.2. DNV Report 98 – 0158. Det Norske Veritas, Høvik. Soma, T., 1998, Effectiveness of Maritime Safety Measures. Master’s Thesis. Division of Marine systems design. Norwegian University of Science and Technology. Trondheim.
Appendix The following three tables give a more detailed definition of basic and direct causes and control areas. Basic cause
Basic causes are structured in 3 groups and 14 factors. Basic cause
Personnel Factors
Lack of skill Inadequate physical and physiological capability Lack of motivation Lack of knowledge
Organizational and Management Factors
Job Factors
Inadequate mental or physiological state Inadequate tools and equipment Inadequate environm. conditions Physical stress
Description, keywords Task knowledge, instruction, practice, routine, infrequent performance, seaman-ship, lack of familiarity with vessel and systems, inadequate psycho-motoric ability. LTA height, reach, range of body movement, senses: vision or hearing deficiency, respiratory incapacity, permanent sickness: allergies etc., sensitivity to extreme conditions, otherwise functionally retarded, disabled. lack of discipline, "cut corners", lack of personal integrity, prestige, hard- headedness, abuse, misuse, improper conduct, sabotage, macho-culture, "horse-play", practical skills. LTA language and communication ability, LTA computation, logic and reasoning, mental models and spatial orientation inadequate, limited experience, training for position in general is inadequate. frustration, preoccupation with problems, negative attitude, LTA co-ordination, reaction time, inability to comprehend, poor judgement, "tunnel vision", reaction to mental overload. mental illness, fears, phobias right tools and equipment unavailable, LTA assessment of needs and risks, inadequate tool or aid, inadequate standards or specifications, use of wrong equipment. too high traffic density, hindrances in the seaway, restricted fairway.
noise, vibration, sea motion, acceleration, climate, temperature, toxic substances, other health hazards, sea sickness, lack of oxygen, other extreme environmental loads. LTA ergonomic conditions antropometric factors, dimensions, lack of information, inadequately presented information, display design, controls, inadequate illumination, workplace messed up, disorder. Lack of supervision lack of instructions, supervision, coaching and feedback, unclear orders, conflict orders, too many "bosses", expectations of supervisor is unclear or not presented, cross-pressure from schedule and economy, inappropriate peer pressure, inappropriate supervisory example, initiated unusual task without proper planning and preparation, lack of initiative to deal with unplanned situations or emergencies, supervisors not in touch with daily operations. Inadequate organizational Unable to communicate safety policy and ethical values, do not set standards by own example, values / climate lack of concern and vigor for quality improvement, incentive, LTA reward system, failure to value results, lack of recognition, personal liability, do not invite incident reporting and improvement suggestion, lack of company loyalty and commitment, do not accept company values, high turn over and absenteeism, lack of continuity. opportunity for learning, personal growth and advancement. Inadequate cultural and social language problems, social and cultural conflicts, person-to-person conflicts and animosity, factors tendency to "cut corners", LTA safety awareness, "cowboy" attitudes, horseplay, resistance to change, inability to learn Inadequate management and too wide span, lack of delegation, authoritarian, hierarchic, command style management, communication unclear rules and responsibility, unresponsive to feedback information and signals from employees, lack of communication and co-ordination across functions/departments. Inadequate Manning and Job inadequate manning, too high workload, idleness, waiting, Job is unattractive, lack of Job content satisfaction and variation, monotony, lack of responsibility for own Job or responsibility not stated clearly.
Direct causes
The direct causes are related to navigation and shiphandling and consists of 9 groups and 29 factors . See table next page.
LTA Tug Assistanc e
LTA Maneu vering
Exte rnal Fact
Incompetent Control
Technical Failure
LTA External Support
Incompetence of OOW
LTA Bridge Equipment
Incapacitation of OOW
Direct cause Absent, absorbed Inattention Too High Work Load LTA Bridge Equipment LTA Radar Equipment Chart not updated No Course Alarm No Depth Alarm LTA Trip Plan Inadeq navigation performance No Double Checking LTA Lookout and Plotting Alternative equipmnt not used LTA Support Pilot LTA Support VTMS LTA Markers & Buoys Few Visual Cues Failure of Control System Failure of Rudder, Hydraulic system Failure of Anchor
Description, keywords Frequency per hour where an officer on watch is not present at the bridge when he should be there, or that an officer on watch is absorbed and do not detect that a hazardous situation is coming up, and this causes Loss of Navigational Control. Frequency per hour where an officer for some reason is inattentive and therefore do not detect that a hazardous situation is coming up, and this results in Loss of Navigational Control. Frequency per hour where an officer has too high work load and due to that doesn't carry out his tasks satisfactorily, and this causes Loss of Navigational Control. Frequency per hour where the conditions concerning design of the equipment on the bridge are less than adequate, e.g. unfortunate design of bridge, lacking or wrong location of equipment, equipment not placed where it is natural to use it, poor and worn out equipment etc., and this results in Loss of Navigational Control. Frequency per hour where the radar equipment doesn't work satisfactory, and this causes Loss of Navigational Control. Frequency per hour where there are faults with charts or publications, or the charts or other document for the voyage are not amended, and this causes Loss of Navigational Control. Frequency per hour where there is no course alarm which indicates when the ship is out of course, and this results in Loss of Navigational Control. Frequency per hour where there is no depth alarm which indicates when the depth and draught ratio is critical, and this causes Loss of Navigational Control. Frequency per hour where the trip plan is not adequate, e.g. tasks as maneuvering, night voyage etc. are not well enough planned, and this causes Loss of Navigational Control. Frequency per hour where the navigation performance is inadequate, e.g. try to go through with the operation even though the conditions are not favorable, and this causes Loss of Navigational Control Frequency per hour where no double checking take place and this results in Loss of Navigational Control. Frequency per hour where inadequate lookout and plotting, e.g. misjudgment of own vessel's movements or not adequate observation of own position, results in Loss of Navigational Control. Frequency per hour where alternative available equipment, as for instance available navigation aids or alternative navigation systems, are not used and this causes Loss of Navigational Control. Frequency per hour where the support of a pilot is inadequate and this causes Loss of Navigational Control. Frequency per hour where the support of VTMS is lees then adequate and this results in Loss of Navigational Control. Frequency per hour where markers and buoys are less then adequate causing Loss of Navigational Control. Frequency per hour where few visual cues causes Loss of Navigational Control of control. Frequency per hour where there is a failure of the control system, e.g. a technical fault with the steering systems or a technical fault with the control/ remote control/ automatic controls/ warning equipment, or wrong design of control, steering system etc., and this causes Loss of Navigational Control. Frequency per hour where a technical rudder or hydraulic failure causes Loss of Navigational Control.
Frequency per hour where a technical fault with the anchor and /or its equipment results in Loss of Navigational Control. Too High Speed Frequency per hour where too high speed, e.g. caused by insufficient formal or competence, or other conditions concerning routines, procedures, communication and organization, causes Loss of Navigational Control. Inadequate Frequency per hour where inadequate operation of the control system, e.g. caused by insufficient operation of formal or competence, or other conditions concerning routines, procedures, communication and Control System organization, results in Loss of Navigational Control. LTA Ship Handling Frequency per hour where less then adequate ship handling, e.g. caused by insufficient formal or competence, or other conditions concerning routines, procedures, communication and organization, causes Loss of Navigational Control. Extreme Wind, Frequency per hour where current in the sea, wind etc. lead to strong drift or other maneuver difficulties Current etc. which result in Loss of Navigational Control. Channel / shallow Frequency per hour where channel or shallow water effect causes Loss of Navigational Control. Course unstable Frequency per hour where the course is unstable due to the ships maneuvering characteristics and this results in Loss of Navigational Control. Too large turning Frequency per hour where the ship's turning radius causes Loss of Navigational Control. Radius Inadequate Tug Frequency per hour where an inadequate tug operation, e.g. failure of procedure or co-operation Operation between vessel and towboat, poor organization from the shore or suchlike, will result in Loss of Navigational Control. LTA Tug Power Frequency per hour where the tug has less than adequate power and this causes Loss of Navigational Control.
Main control areas
1
Main Control Areas Technical
2
Personnel
3
Operational
4
Safety Management
5
Top Level Management
6
Infrastructure
Description of specific measures Improved reliability and availability improved performance of existing systems New function of aids Instrumentation Monitoring Automation Improved human- machine interface Improved work-place conditions Selection and check of competence Education and training Leadership and supervision Motivation : Modification of attitudes Development of social climate Inspection methods Maintenance procedures and methods Operation procedures / systems Documentation Manning and watch systems Management : Organisation, routines Risk analysis: Safety case Inspection and auditing Experience feedback, learning Health, environment, safety work Develop safety policy Budgeting, rescue allocation Leadership philosophy Weather forecasting, routing service Development of tug and salvage service Strengthen Port State control Upgrade VTMS facilities and service