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Enhancement of occupational health and safety requirements in chemical tanker operations: The case of cargo explosion
Safety Science 48 (2010) 195–203
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Enhancement of occupational health and safety requirements in chemical tanker operations: The case of cargo explosion Metin Celik * Department of Maritime Transportation and Management Engineering, Istanbul Technical University, Tuzla 34940, Istanbul, Turkey
a r t i c l e
i n f o
Article history: Received 6 January 2009 Received in revised form 23 July 2009 Accepted 13 August 2009
Keywords: Chemical tanker operations Occupational health and safety Shipping accidents Fuzzy axiomatic design Analytic hierarchy process
a b s t r a c t Operational precautions for chemical tankers are vitally important in reducing the potential threat to shipboard crew by products carried. This paper enhances the International Safety Management (ISM) code in compliance with Occupational Health and Safety Management Systems (OHSAS 18001:2007) requirements in respect to operational constraints related to chemical tankers. As research methodology, Fuzzy Axiomatic Design (FAD) and Analytic Hierarchy Process (AHP) are referred to redesign the extended ISM code procedure, which identifies key points for occupational accident prevention on board chemical tankers. To illustrate the expected benefits of an extended ISM code procedure, the principle root causes of chemical tanker explosion are also discussed. In particular, the main results of the case study highlight the urgent need to ensure the competency of shipboard personnel and their familiarization with the characteristics of chemical cargos under differing circumstances. The outcomes set out in this paper contribute to regulatory compliance and to the management of occupational health and safety requirements on board chemical tankers. Ó 2009 Elsevier Ltd. All rights reserved.
1. Potential hazards in chemical tanker operations The transport of chemicals represents a significant portion of total worldwide freight (Erera et al., 2005). Therefore, the chemical industry needs to utilize various transportation modes such as air, pipeline, marine, rail, and road. Among these, marine transportation is recognized as a significant network. By carrying chemical products in bulk via specially designed vessels, it is highly important for the sustainability of chemical processing industry. However, maritime transportation is threatened by various hazards such as fire, explosion, and toxic release (Khan and Abbasi, 1999). Furthermore, major catastrophic events involving chemical tankers (Haastrup and Brockhoff, 1990) have threatened human life and the maritime environment. Aside from shipping accidents, the routine operations on board chemical tankers (i.e. cargo handling, tank inspection, gas-freeing, tank cleaning, tank purging, etc.) also have additional risks – especially for seafarers (Arslan and Er, 2008). Experience has pointed out that understanding and controlling these hazards is of vital importance not only in the design and construction stages of chemical tankers but also in their operation processes (Romer et al., 1993; Rao and Raghavan, 1996; Shaluf et al., 2003; Jetlund and Karimi, 2004). Shipping casualties during the transportation of large quantities of liquid bulk chemicals may have acute and chronic effects on both marine * Tel.: +90 216 395 1064; fax: +90 216 395 4500. E-mail address: [email protected] 0925-7535/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.ssci.2009.08.004
habitats and the accommodation and working spaces of tanker ships (Arslan and Er, 2008). Recent innovations in marine technology have reinforced safety precautions (Wang, 2002; Hetherington et al., 2006) which can improve construction and operating systems on board tanker ships. Nevertheless, the familiarization of shipboard crew to different freights is still not qualified according to the physical properties and chemistry of different cargo types (i.e. petrochemical products, coal tar products, alcohols, heavy chemicals, etc.) especially during cargo-handling operations. The serious effects of different cargo related to such characteristics as flammability, toxicity, corrosiveness and self-reaction ought to be monitored by the shipboard crew regularly. All these constraints require technical support for the shipboard crew aboard chemical tankers. Relevance to solutions for these operational issues, responsible managers can follow the specialized procedures based on the operating environment of chemical tankers to ensure an appropriate shore-based and shipboard interface. In addition to operational risks due to cargo characteristics, external pressure by Non-Governmental Organizations (NGOs) and global cargo owner associations have also forced chemical tanker operators to maintain standards at reliable levels due to the potentially extraordinary catastrophic effects of chemical tanker accidents. The International Safety Management (ISM) code provides a fundamental international standard for ensuring safe management and pollution prevention during operation of ships (Glazar, 1998). It is mandatory for passenger ships, oil/chemical
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tankers, gas carriers, bulk carriers, high-speed cargo craft of 500 gross tonnages and upwards, other cargo ships, and mobile offshore drilling units of 500 gross tonnage and upwards. However, it should be recognized that the current implementation of the ISM code cannot appropriately fulfil expectations – especially those directed at enhancing occupational health and safety requirements. This is due to the complexity of chemical tanker operations. The potential threats particular to specific freights also require that those dealing with them can do so with a high level of competence. Specifically, the International Code for the Construction and Equipment of Ships carrying Dangerous Chemicals in Bulk (IBC Code) and The International Maritime Dangerous Goods (IMDG) Code can be cited as specialized regulatory provisions regarding chemical tanker operations. The IBC Code aims mainly to prescribe design and construction standards of ships in order to minimize risks to vessels, crews and the environment while the IMDG Code was developed as an international code for the transport of dangerous goods by sea covering such matters as packing, container traffic, and stowage. When the relevant regulations are analysed in detail, those actually dealing with occupational health considerations appear rare. In addition, actual implementation of these codes creates excessive bureaucrat work within the shipping trade, which in turn triggers reduction of implementation performance at the operational level. In addition to this, continuing shipping casualties and injuries clearly indicate the need for simplified and practical execution procedures in order to ensure fast decision-making – especially in enhancing occupational health and safety requirements aboard chemical tankers. To achieve this, the necessity for a new safety regime covering both operational and occupational aspects needs to be addressed. According to this insight, the following issues should be addressed as they can be expected to arise during management system design: (i) regulatory compliance; (ii) integration; (iii) implementation performance. Hence, this research especially focuses on intensification of ISM code practice in chemical tanker shipping in order to prevent or reduce the effects of hazardous cargo on the shipboard crew. Specifically, this paper follows Fuzzy Axiomatic Design (FAD) and Analytic Hierarchy Process (AHP) methodologies to integrate the recent version of the Occupational Health and Safety Management Systems (OHSAS 18001:2007) requirements into the ISM code to redesign a specialized implementation procedure with high level of compliance. This section motivates the required attitude towards hazardous chemical cargo, the current regulatory framework, and the urgent need for enhancing occupational health and safety requirements on board chemical tankers. Section 2 introduces the theoretical background of FAD and AHP methodologies. In Section 3, the proposed hybrid methodology for coupling the ISM code and OHSAS 18001:2007 requirements by a specific implementation scheme is performed. Following a discussion of the significance of enhanced ISM code procedures on potential chemical tanker casualties, conclusive remarks, and proposals for further research are made.
Axiomatic design theory led theorists to define two design axioms: the independence axiom and the information axiom. The independence axiom states that a good design is one that maintains the independence of the Functional Requirements (FRs). The information axiom states that, among the design alternatives that satisfy the independence axiom, the best alternative is the one that has the lowest information content (Suh, 2007). In recent years, the fuzzy extension of axiomatic design methodology called ‘‘Fuzzy Axiomatic Design” (FAD) (Kulak and Kahraman, 2005a) provides opportunities for solving decisionmaking problems under multiple criteria. Since it is a relatively new tool in decision-making, FAD has had only a few applications (Kulak et al., 2005; Kulak and Kahraman, 2005b; Eraslan et al., 2006; Celik et al., 2009a; Celik, 2009a; Celik et al., 2009b; Celik 2009b). Recently, it has been more extensively dealt with in the literature. In existing applications of FAD methodology, the total information contents of the different alternatives are also utilized for selection, ranking, and strategy-making purposes. FAD has three principal dimensions: system range, decision range, and common range. Fig. 1 illustrates the relations between these parameters in Triangular Fuzzy Number (TFN) form. Principally, the information content of a design is calculated according to the following equation (Kulak and Kahraman, 2005a; Celik et al., 2009a; Celik, 2009a):
I ¼ log2
TFN of system range common area
ð1Þ
In Fig. 1, the corresponding TFN for each dimension is bound to the highest value of membership function – denoted as l(x). After defining the TFN for system range and decision range, a common area appears. The different units for these measures are unified by utilizing a logarithmic base. In the further section of this paper, the conformity levels of ISM code clauses are quantitatively evaluated with respect to the requirements of OHSAS 18001:2007. The total information contents of each clause provide opportunities for redesigning the current implementation procedure of the ISM code to incorporate the existing occupational health and safety requirements. Table 1 illustrates the fuzzy scale for defining FRs
µ (x)
TFNs of System Range
TFNs of Decision Range
a
c
1
x b
d
Common area 2. Background of research methodology
Fig. 1. Definitions of principal dimensions in TFNs forms.
2.1. Theory and practice of FAD The FAD methodology is structured based on axiomatic design principles (Suh, 1990) having the following fundamental concepts: (1) design as a mapping process; (2) design abstraction in the hierarchical structure; (3) design laws in the form of axioms; (4) design equations as notation for representing functional dependencies (Lo and Helander, 2007). In practice, the designers apply the advantages of axiomatic design foundation to improve the design process.
Table 1 Fuzzy scale for defining of FRs. Linguistic terms on conformity degree
TFNs
Clauses at least fully conforming (FC) Clauses at least substantially conforming (SC) Clauses at least partially conforming (PC) Clauses at least low conforming (LC) Closes at least very low conforming (VLC)
(0.8, 1, 1) (0.6, 1, 1) (0.4, 1, 1) (0.1, 1, 1) (0, 1, 1)
M. Celik / Safety Science 48 (2010) 195–203 Table 2 Fuzzy scale for conformity level assessment. Conformity level
TFNs
Very high (VH) High (H) Medium (M) Low (L) Very low (VL)
(0.8, 1, 1) (0.6, 0.9, 0.9) (0.4, 0.7, 0.7) (0.1, 0.5, 0.5) (0, 0.3, 0.3)
Table 3 Saaty’s scale of relative importance. Linguistic judgments
Values
Equal importance Weak importance Strong importance Demonstrated importance Absolute importance Intermediate values between judgments
1 3 5 7 9 2, 4, 6, 8
over relevant requirements as evaluation attributes. Table 2 illustrates the corresponding TFNs for the linguistic terms (Celik 2009b), which are planned to measure conformity levels of ISM code clauses with OHSAS 18001:2007 requirements. 2.2. AHP methodology The AHP is one of the mostly utilized decision-making tools used in comparing a number of alternatives with respect to an overall goal under a multiple criteria decision environment (Saaty, 1980; Saaty, 1986). In addition to ensuring consistent outcomes among problem alternatives, the AHP also leads to obtaining priorities of relevant attributes in a subsequent hierarchic structure. A wide range of theoretical information regarding the mathematical concepts involved in AHP methodology can be found within the contents of previously published research papers (Saaty, 1990; Saaty 1991; Saaty, 1994). Applications of the AHP methodology have appeared in a great number of fields (Golden et al., 1989; Kumar and Vaidya, 2006). In this study, the hierarchic structure of OHSAS 18001:2007 requirements is decomposed and assessed comparatively. Then, the priority weights of each element are computed with respect to the operational constraints of chemical tankers. The Saaty’s scale of relative importance shown in Table 3 (Saaty, 1990) is utilized to prioritize the weights of OHSAS 18001:2007 requirements by considering the potential hazards of operating environments aboard chemical tankers. Specifically, integration of the AHP into research methodology provides priority values for the requirements of OHSAS 18001: 2007. These values subsequently enable a reference point for decision-makers in the design process of integrated management system. Therefore, the function of the AHP is to assist in establishing standardized compliance with chemical tanker operating environment and maritime regulations. 3. Proposed model 3.1. Problem statement The main aim of this study is to ensure the provision of the information required for redesigning ISM code procedures in order to couple them with the OHSAS 18001:2007 requirements under a single implementation scheme. At this point, the hybrid approach with AHP and FAD methodologies provides quantitative outcomes
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over ISM code clauses regarding compliance levels which can be recognized as a decision aid for ensuring a ‘state of the art‘ system redesign process. This means that a high level of compliance between the ISM code and OHSAS 18001:2007 can be achieved by measuring expectations in terms of defining FRs for each clause of the ISM code and weighting the requirements of OHSAS 18001:2007 in respect to the potential hazards aboard chemical tankers. Before performing solution algorithm, current implementation procedure of the ISM code in chemical tanker fleets and the recently updated version of OHSAS 18001:2007 are introduced as technical background information within the following sub-sections entitled: 3.1.1 ISM code Implementation for Chemical Tankers and 3.1.2 Expected Contributions of OHSAS 18001:2007 in Chemical Tanker Environment. 3.1.1. ISM code implementation for chemical tankers Technical analyses of the details of shipping accident statistics (O’Neil, 2003; Baker and McCafferty, 2005) underline the great necessity to improve safety management systems and shore-based organization both in shipping companies ashore and shipboard hierarchy aboard. Thus the ISM code contributes not only to the safe operation of ships and protection of the environment but also critically influences the style of management in a shipping company and improves the entire quality of management resulting in better business outcomes. Therefore, responsible shipping company managers should be fully committed to implementing the ISM code into fleet operational procedures. The ISM code can be divided into two main sections: (1) implementation and (2) certification and verification. These two sections contain a total of 16 clauses. The implementation process of the ISM code is divided into 12 distinct clauses as follows: general (clause 1); safety and environmental protection policy (clause 2); company responsibilities and authority (clause 3); designated person(s) (clause 4); master’s responsibility and authority (clause 5); resources and personnel (clause 6); development of plans for shipboard operations (clause 7); emergency preparedness (clause 8); reports and analysis of nonconformities, accidents, and hazardous occurrences (clause 9); maintenance of the ship and equipment (clause 10); documentation (clause 11); company verification, review, and evaluation (clause 12); certification and periodical verification (clause 13); interim certification (clause 14); verification (clause 15); forms of certificates (clause 16) are the clauses contained within the second part of the ISM code. In the chemical tanker operating process, the contributions of the ISM code practice have seemed especially significant in the development and implementation of operational and emergency plans relevant to chemical tankers. In a broad sense, the plans for tanker operations are prepared in accordance with the following constraints: (1) operational orders; (2) company procedures; (3) ISM code requirements; (4) other regulatory requirements. The ISM code has serious advantages especially regarding the development of vessel emergency plans, the carrying out of emergency shutdowns of chemical cargo operations, in special precautions being taken while carrying out maintenance, in the application of first aid in relation to chemical cargo accidents, in using resuscitation equipment and breathing apparatus, in carrying out safe entry into and rescue from enclosed spaces, and in taking appropriate action in the event of catastrophes such as collision and chemical spillage. However, the links for sustaining the occupational healthcare and safety precautions regarding the varying hazards of cargo in different operations are not clearly identified. Therefore, the ISM code implementation procedure should be extended operationally to clearly identify typical emergency problems and potential hazards on board chemical
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tankers in order to be able to promptly initiate appropriate corrective/preventive actions. 3.1.2. Expected contributions of OHSAS 18001:2007 aboard chemical tanker Following the research methodology, the requirements of OHSAS 18001:2007 can be considered as a hierarchical decision structure (ISO, 2009). Then the priority weights of each requirement can be assigned based on AHP. In the first level of hierarchy, the general requirements-4.1, policy-4.2, planning-4.3, implementation and operation-4.4, checking-4.5, and management review-4.6, denoted by R1, R2, R3, R4, R5, R6 are the main requirements of OHSAS 18001:2007. In the planning stage, hazard identification, risk assessment and determining controls-4.3.1 (R31), legal and other requirements-4.3.2 (R32), objectives and programs-4.3.3 (R33) are the sub-requirements. As the most significant process of OHSAS 18001:2007 bodies, the implementation and operation stages include the following sub-requirements: resources, roles, responsibility, accountability and authority-4.4.1 (R41), competence, training, awareness-4.4.2 (R42), communication, participation, and consultation-4.4.3 (R43), documentation-4.4.4 (R44), control of document4.4.5 (R45), operational control-4.4.6 (R46), emergency preparedness and response-4.4.7 (R47). In addition, performance measurement and monitoring-4.5.1 (R51), evaluation of compliance-4.5.2 (R52), incident investigation, nonconformity, corrective and preventive action-4.5.3 (R53), control of records-4.5.4 (R54), internal audit-4.5.5 (R55) are the sub-attributes of checking-4.5 procedures. Table 4 summarizes the requirements of OHSAS 18001:2007. In practice, implementation of the OHSAS 18001:2007 requirements can be regarded as challenges for reducing occupational hazards and improving working conditions especially in the cases of the following special processes and duties on board chemical tankers: (1) enclosed space and cargo tank entries; (2) working on pipelines and pressurized pipes; (3) testing of cargo pump operations and functionality; (4) operations on and maintenance of cargo heating system; (5) testing of cargo valves and houses on board ship; (6) calibration of toxic gas detection, explosive meter, and oxygen meter. Furthermore, the requirements of clause-4.3.1 enable the definition of hazards associated with chemical cargoes including understanding of the types of hazards and their causes, safety and hazard minimization procedures used on chemical tankers, potential health hazards of various chemical cargoes, basic toxicological terminology, routes of entry of toxins to the human
body, and other safety related matters. The integrated execution plan of the ISM code and OHSAS 18001:2007 standards on board chemical tankers deals with the serious drawbacks in various procedures such as ventilation of spaces, cargo related processes, emergency preparedness. However, both managers in the shorebased organization and shipboard personnel require a welldesigned implementation procedure to increase the benefits from extended ISM code procedure. 3.2. Performing of model algorithm The mathematical algorithm of the proposed hybrid approach is performed at five stages as follows: (1) computing the priority weights on OHSAS 18001:2007 requirements; (2) assigning judgments over FRs and ISM code clauses; (3) performing of fad; (4) deriving final outcomes; (5) utilization of model outcomes for redesigning of ISM code procedure. 3.2.1. Stage 1: computing the priority weights on OHSAS 18001:2007 requirements The AHP methodology is performed over the hierarchic structure of OHSAS 18001:2007 requirements. The group aggregation of the expert judgments is inserted into the Superdecisions Software. The expert profile consists of representatives from maritime professional and administrative organizations, responsible managers and quality executives from ship management companies. In detail, the expert judgements recognize the opinions of professional managers and marine superintendents (especially from technical departments of shipping companies) who have a seagoing background and professional execution experience. A meeting was held to incorporate their judgements into the model by group consensus. The aggregate judgements then provided the required input data for the AHP algorithm. After structuring the decision matrix, the priority weights on the requirements of OHSAS 18001:2007 are then computed based on AHP by Superdecisions Software. Tables 5 and 6 illustrate the priority weights on attributes according to different levels of hierarchy. The derived values can be recognized as reference points in the system design of an extended ISM code procedure. It means that the priority values of standard requirements are utilized to decide the importance levels of each requirement. The priority weights on attributes allow the decision-makers to identify the significant points of management system
Table 4 Requirements of OHSAS 18001:2007. OHSAS 18001:2007 Main requirements
Code
Sub-requirements
Code
General requirements (4.1) Policy (4.2)
R1 R2
Planning (4.3)
R3
Implementation and operation (4.4)
R4
Checking (4.5)
R5
Management review (4.6)
R6
NA NA Hazard identification, risk assessment and determining controls (4.3.1) Legal and other requirements (4.3.2) Objectives and programs (4.3.3) Resources, roles, responsibility, accountability and authority (4.4.1) Competence, training, awareness (4.4.2) Communication, participation, and consultation (4.4.3) Documentation (4.4.4) Control of document (4.4.5) Operational control (4.4.6) Emergency preparedness and response (4.4.7) Performance measurement and monitoring (4.5.1) Evaluation of compliance (4.5.2) Incident investigation, nonconformity, corrective and preventive action (4.5.3) Control of records (4.5.4) Internal audit (4.5.5) NA
– – R31 R32 R33 R41 R42 R43 R44 R45 R46 R47 R51 R52 R53 R54 R55 –
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priorities of different chemical tanker operating companies (i.e. company vision/mission, operating policy, etc.). Therefore, further modifications regarding implementation of ISM code clauses can be initiated with respect to the occupational health and safety policies of chemical tanker shipping firms. According to this insight, the AHP provides the responsible executives with great flexibility in system design. It means that it is possible to refer to different ranking orders of the ISM code clauses to comply with the OHSAS 18001:2007 requirements.
Table 5 Computed priority weights for main attributes. Attributes (requirements)
Normalized values
Limiting values
R1 R2 R3 R4 R5 R6
0.165 0.246 0.117 0.213 0.118 0.141
0.114 0.170 0.081 0.147 0.082 0.097
3.2.2. Stage 2: assigning judgments over FRs and ISM code clauses The second stage of the solution algorithm requires assigning the consistent judgments to identify the FRs for the focused system. Table 7 illustrates the expectations of the different maritime trade executive groups for the requirements of the OHSAS 18001: 2007 standardization system for chemical tanker operations. The assigned TFN values indicate the expectations of conformity level among the ISM code clauses and OHSAS 18001 requirements. In addition, relevant judgments are required for the different clauses of the ISM code in order to enable their classification with respect to their conformity levels. Hence, the linguistic terms in TFNs are assigned for each clause of the ISM code in Table 8. Principally, the assigned judgements reflect the ideas regarding conformity levels of different clauses for each requirement of the OHSAS 18001:2007.
Table 6 Computed priority weights for sub-attributes. Sub-attributes (Sub-requirements)
Normalized values
Limiting values
R31 R32 R33 R41 R42 R43 R44 R45 R46 R47 R51 R52 R53 R54 R55
0.464 0.281 0.255 0.167 0.251 0.093 0.070 0.087 0.146 0.187 0.259 0.207 0.219 0.176 0.138
0.037 0.023 0.021 0.025 0.037 0.014 0.010 0.013 0.021 0.027 0.021 0.017 0.018 0.014 0.011
3.2.3. Stage 3: performing of FAD First, aggregation of the judgements given in Table 7 is performed by following one of the common aggregation approaches proposed by Chen (1998). The aggregated results of the linguistic judgments over FRs in TFNs form are illustrated in Table 9.
requirements of OHSAS 18001:2007 for chemical tanker operations. As previously mentioned, the revealed outcomes from AHP provide a decision aid in advanced management/execution/operating system design. This may influence the results according to the
Table 7 FRs over OHSAS 18001:2007 requirements. Maritime expert groups
Management system requirements (OHSAS 18001:2007) R1
Ship managers Standardization system executives Administrative organizations
PC LC LC
R2
R3
PC SC PC
R4
R5
R6
R31
R32
R33
R41
R42
R43
R44
R45
R46
R47
R51
R52
R53
R54
R55
SC SC PC
PC SC PC
PC SC SC
PC SC PC
PC PC PC
LC PC PC
LC PC VLC
VLC PC PC
PC SC SC
SC SC PC
SC PC LC
PC LC PC
LC PC SC
PC PC PC
PC LC PC
LC PC LC
Table 8 Judgments on conformity levels of ISM code clauses. ISM code
Management system requirements (OHSAS 18001:2007) R1
Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
M M L L L L L L L L L L L VL L L
R2
H H M L L M L L L L L L L VL L L
R3
R4
R5
R6
R31
R32
R33
R41
R42
R43
R44
R45
R46
R47
R51
R52
R53
R54
R55
M M H M M L H L M M M H L VL M VL
L M M L L M M M M L M M M M M VL
M H H M M M H M M H M M L L VL VL
L L VH VH VH H H M M M L M L VL L VL
L L VH H H VH H H L H L M L M L L
M H H M H H H M L M M L M M L VL
VL L M M H L M L L L VH L M L VL L
VL VL M VL M VL M M L M VH L M VL VL VL
L M H H H H VH VH M M M M L L L VL
L M VH M VH H VH M M VH M M L M M VL
M L H M H M H L M M M H VL VL L L
L L H M H L H L L L M L VL VL L VL
L VL H M H M M L VH M L M VL L L VL
L VL M M M VL M VL L L VH L L VL VL M
VL VL H M H L L M M M L VH VL VL L VL
VL VL H M VH L L M M M L VH L VL VL VL
200
Table 9 Aggregated FRs values in TFNs form. Management system requirements (OHSAS 18001:2007) R2
R1
(0.197, 1, 1)
(0.466, 1, 1)
R3
R4
R5
R6
R31
R32
R33
R41
R42
R43
R44
R45
R46
R47
R51
R52
R53
R54
R55
(0.534, 1, 1)
(0.466, 1, 1)
(0.534, 1, 1)
(0.466, 1, 1)
(0.400, 1, 1)
(0.303, 1, 1)
(0.164, 1, 1)
(0.271, 1, 1)
(0.534, 1, 1)
(0.534, 1, 1)
(0.368, 1, 1)
(0.303, 1, 1)
(0.368, 1, 1)
(0.400, 1, 1)
(0.303, 1, 1)
(0.197, 1, 1)
M. Celik / Safety Science 48 (2010) 195–203
Table 10 Distribution of information contents over ISM code clauses. ISM code
Management system requirements (OHSAS 18001:2007) R1 0.165
Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
0.904 0.904 1.810 1.810 1.810 1.810 1.810 1.810 1.810 1.810 1.810 1.810 1.810 4.515 1.810 1.810
R2 0.246
0.110 0.110 1.545 7.495 7.495 1.545 7.495 7.495 7.495 7.495 7.495 7.495 7.495 INF 7.495 7.495
R3 0.117
R4 0.213
R5 0.118
R6 0.141
R31 0.464
R32 0.281
R33 0.255
R41 0.167
R42 0.251
R43 0.093
R44 0.070
R45 0.087
R46 0.146
R47 0.187
R51 0.259
R52 0.207
R53 0.219
R54 0.176
R55 0.138
2.350 2.350 0.174 2.350 2.350 INF 0.174 INF 2.350 2.350 2.350 0.174 INF INF 2.350 INF
7.490 1.544 1.544 7.490 7.490 1.544 1.544 1.544 1.544 7.490 1.544 1.544 1.544 1.544 1.544 INF
2.350 0.174 0.174 2.350 2.350 2.350 0.174 2.350 2.350 0.174 2.350 2.350 INF INF INF INF
7.490 7.490 0.000 0.000 0.000 0.110 0.110 1.544 1.544 1.544 7.490 1.544 7.490 INF 7.490 INF
4.585 4.585 0.000 0.123 0.123 0.000 0.123 0.123 4.585 0.123 4.585 0.737 4.585 0.737 4.585 4.585
0.755 0.178 0.178 0.755 0.178 0.178 0.178 0.755 2.840 0.755 0.755 2.840 0.755 0.755 2.840 INF
3.767 1.569 0.964 0.964 0.271 1.569 0.964 1.569 1.569 1.569 0.000 1.569 0.964 1.569 3.767 INF
8.065 8.065 0.790 8.065 0.790 8.065 0.790 0.790 2.480 0.790 0.000 2.480 0.790 8.065 8.065 8.065
INF 2.350 0.174 0.174 0.174 0.174 0.000 0.000 2.350 2.350 2.350 2.350 INF INF INF INF
7.291 2.350 0.000 2.350 0.000 0.174 0.000 2.350 2.350 0.000 2.350 2.350 INF 2.350 2.350 INF
0.722 3.863 0.138 0.722 0.138 0.722 0.138 3.863 0.722 0.722 0.722 0.138 INF INF 3.863 3.863
2.840 2.840 0.178 0.755 0.178 2.840 0.178 2.840 2.840 2.840 0.755 2.840 INF INF 2.840 INF
3.862 INF 0.138 0.722 0.138 0.722 0.722 3.862 0.000 0.722 3.862 0.722 INF 3.862 3.862 INF
4.585 INF 0.737 0.737 0.737 INF 0.737 INF 4.585 4.585 0.000 4.585 4.585 INF INF 0.737
INF INF 0.178 0.755 0.178 2.840 2.840 0.570 0.755 0.755 2.840 0.000 INF INF 2.840 INF
4.515 4.515 0.248 0.904 0.000 1.810 1.810 0.626 0.904 0.904 1.810 0.000 1.810 4.515 4.515 4.515
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Based on the FAD algorithm, the information contents are computed using the Eq. (1). Distribution of information contents over ISM code clauses. This is illustrated in Table 10.
Table 11 Ranking of ISM code clauses. Rank
ISM code
P
1 2 3 4 5 6 7 8
Clause Clause Clause Clause Clause Clause Clause Clause
0.882 2.682 2.861 2.899 3.145 3.175 3.401 3.830
3 5 12 7 10 4 9 11
I
3.2.4. Stage 4: deriving final outcomes The weighted information contents over ISM code clauses support the final outcomes for initiating the redesign process of ISM code procedure. Based on the results, eight of the clauses are compliance with the OHSAS 18001:2007 requirements while those remaining have considerable problems in coupling with the ISM
INITIATE: Motivate to redesign the ISM Code procedure to comply with the OHSAS 18001:2007 requirements Pre-identification of potential hazards for chemical tanker operations
Establish the ISM Code-Clause 3 with respect to Clause 4.4.1 and Clause 4.4.6 of OHSAS 18001:2007 Maintain the requirements of the ISM Code-Clause 5 with respect to Master’s authority and responsibility in terms of Clause 4.3.2 of OHSAS 18001:2007 Yes
Yes
Does it satisfy with the Clause 4.4.7 of OHSAS 18001:2007?
No
Yes
Review the new procedure in accordance with the ISM Code-Sub clause 1.4 and Clause 4.3.1 of OHSAS 18001:2007
Prepare draft requirements of audit process for operational safety complying with ISM Code-Clause 12 and Clause 4.3.1 of OHSAS 18001:2007
No Does it satisfy with the Clause 4.3.3 of OHSAS18001:2007?
Implement the ISM Code-Clause 7 requirements
No
Reassure the ISM Code-Clause 3 & Clause 5
Plan maintenance requirements of shipboard technical system with respect to ISM Code-Clause 10 Implement performance measurement process with respect to Clause 4.3.1 of OHSAS 18001:2007. Implement shipboard emergency procedure for the ISM Code-Clause 8
Does it constitute with DPA execution activities?
Implement ISM Code-Clause 9 and Clause 4.5.3 of OHSAS 18001:2007 under a unique procedure
No
Yes Implement ISM Code-Clause 12 and Clause 4.5.2 & 4.5.5 of OHSAS 18001:2007 under a unique procedure
Yes No Does it satisfy with the 4.4.6, 4.5.2 of OHSAS18001:2007? END: Establish extended ISM Code procedure on OHSAS 18001:2007 requirements
No
Yes Does it satisfy shipboard operations Clause 4.4.6 of OHSAS 18001:2007?
Review the satisfaction for ISM Code-Clause 1, 2, 6
No
Satisfy?
Execute the documentation process via Clause 11, Clause 15, Clause 13, Clause 14, and Clause 16 separately
Yes
Fig. 2. Extended implementation procedure on ISM code.
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code. Table 11 gives the ranks of highly conformed ISM code clauses. Nevertheless, the values of total information contents for clause 1, clause 2, clause 6, clause 8, clause 13, clause 14, clause 15, and clause 16 are infinite. The next issue is to utilize those values in the design of extended ISM code procedure. 3.2.5. Stage 5: utilization of model outcomes for the redesigning of ISM code procedure It is planned to utilize the outcomes of the FAD methodology for the implementation of system redesign of ISM code procedures to enhance the occupational health and safety level in chemical tanker operations. Based on the model outcomes, clause 3 has the highest conformity among the ISM code clauses. The assigned rank in Table 11 can be utilized as a decision aid for re-structuring a new implantation procedure of ISM code for chemical tankers operations. Finally, the extended implementation procedure of the ISM code is illustrated in Fig. 2. The extended structure of the ISM code ensures the integration of the special requirements for chemical tanker operations, thus enhancing the occupational health and safety precautions and reducing the possibility for catastrophic failures aboard ships. 4. Case study: linking with chemical tanker accident case 4.1. Introduction to accident case In this section, the strengths and expected contributions of the extended ISM code procedure based on occupational health and safety requirements are considered by studying an a case where a chemical tanker exploded and sank. In 2004, the chemical tanker Bow Mariner caught fire and exploded in the Atlantic Ocean while the crew was engaged in cleaning residual methyl tert-butyl ether (MTBE) from the cargo tank (U.S.C.G, 2005). This had fatal consequences for 21 of the 27 man crew. The environmental impact was considerable as great quantities of MTBE, Ethyl Alcohol, heavy fuel oil, and diesel fuel were released. Briefly, the accident investigation report identified the cause of this accident as being ignition of a fuel/air mixture, either on deck or in the cargo tanks, that was within its flammable limits. The dominant casualty factors had mainly to do with shortcomings in shore-based support and with operator failures on board the chemical tanker. More detailed technical information regarding the different chemical cargoes (i.e. ethyl alcohol, methyl tert-butyl ether) which were present in various tanks is given in Table 12. The basic principal cause of the accident was the lack of awareness and the incompetence of crews responsible for the cargo. A wrong decision was made t open cargo tanks that previously held MTBE thus permitting the accumulation heavier than air flammable vapours on deck. It diluted the fuel-rich atmosphere in the cargo tanks with oxygen, bringing them into the flammable range. Then, the explosion occurred on board due to ignition by one of a number of possible sources considered: cell phone, sabotage, smoking, electrostatic discharge, mechanical spark, or electrical source. Table 12 Properties of ethyl alcohol and methyl tert-butyl ether. Properties
Chemical cargo Ethyl alcohol
UN number Chris code IMO pollution category Grade flash point Specific gravity Vapour density (air = 1.0) Solubility in water
Methyl tert-butyl ether
1170 2398 EAL MBE II D C – flammable liquid 65 °F 14 °F 0.79 0.74 3.1 1.6 Complete Complete
Furthermore, the accident investigation report found certain evidence regarding procedures and regulatory concept: (1) noncompliance with ISM code practice; (2) implementation shortfalls of the safety, quality and environmental protection management system (SQEMS) procedures on board; (3) insufficiency of the inert gas system (IGS) operations; (4) misperception in tank cleaning procedures; (5) misperception in procedures for gas release after tank cleaning. 4.2. Expected contributions of extended ISM code procedure Following the casualty analysis, the paper explores the potential benefits of the extended ISM code procedure. Recalling Fig. 2, the extended ISM code procedure initiates the shipping company responsibility and authority (ISM code-clause 3) in respect to the operational control (sub-requirements 4.4.6 of OHSAS 18001:2007) specific to the potential hazards of chemical tanker operations. This gives a great advantage to shore-based organization and shipboard crews in following safety procedures in the cargo tank cleaning and gas release processes. Based on the investigation report, this accident points to a high level of decision error by the responsible crew members, (especially masters and chief officer), on board. In the extended ISM code procedure, defining a master’s responsibility and authority (ISM code-clause 5) in accordance with legal and other requirements (sub-requirement 4.3.2 of OHSAS 18001:2007) ensures fully compliance of specially designed safety and occupational health procedures for chemical tanker operations. Furthermore, monitoring this process based on sub-requirements-4.3.3 of OHSAS 18001:2007 clearly satisfies especially the need for adequate communication – which was found to be so insufficient in the case discussed. During the preparation of procedures for shipboard operations (ISM code-clause 7), taking emergency preparedness and response (sub-requirements 4.4.7 of OHSAS 18001:2007) into account has vital importance in maintaining occupational health and safety requirements. In the case analysed, a number of crew members died due to the improper application of this critical emergency response. The following of maintenance and emergency procedures, is assigned by the extended ISM code procedure to a Designed Person Ashore (DPA). This provides for a well-controlled and sustainable ship-shore interface in the execution procedure. In the case of this accident, technical support for the newly embarked shipboard crews (chief officer) was severely limited. This was also the case for shipboard personnel competency regarding the properties of the chemical cargo which was the responsibility of the DPA and other technical managers. At this point, the extended ISM code directly assigns the DPA the duty of ensuring the capability of shipboard personnel regarding specific elements of chemical tanker operations. Finally, reviewing the company verification (ISM code-clause 12) for the entire procedure – based on the operational control constraints (sub-requirements 4.4.6 of OHSAS 18001:2007) – is another key point of the proposed system. It appears quite clear that the extended ISM code has strict safety barriers to reduce hazardous occurrences and the potential for catastrophes. The case study addressed the expected contributions of extended ISM Code compliance with OHSAS requirements on board chemical tankers. In particular, the consequences of personnel incompetence in relation to the characteristics of chemical cargos were strongly emphasised; moreover, the potential utility of the proposed extended ISM code/OHSAS 18001:2007 system is clearly introduced. In contrast, the current content of the ISM code enables a broad procedural support of crewmembers to safety and environment-related threats. However, the concept underlying this paper is the extension of this procedural support to occupational health and safety requirements. Thus the key target group of the extended ISM code procedure is shipboard crewmembers. In addition,
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shore-based managers are responsible for ensuring the transformation of redesigned ISM code procedures (specific to chemical tankers) into useful knowledge (i.e. providing operational decision aid) especially for cargo-handling, tank inspection, gas-freeing, tank cleaning, and tank purging operations. Enhancement of shipboard occupational health/safety requirements and their integration by OHSAS 18001:2007 requirements into the existing ISM code framework is the core idea which is reasonably congruent with the case outlined in this paper. This supports the thesis that the enhanced ISM code procedure has a great potential/capability for reducing probable root causes leading to disasters such as the cargo explosion case discussed. When benchmarked with the existing ISM code framework, the practical advantages of the OHSAS 18001-extended ISM code can clearly be seen. 5. Concluding remarks and further research proposals Chemical tanker operations require a high level of safety and environmental-related precautions when relatively compared with other types of merchant ships. Various human-system interactions have occurred during the loading, discharging, tank cleaning, ventilating, and condition monitoring processes of chemical cargo. Reducing catastrophes in chemical tankers requires implementing urgent strategies and fast decision-making procedures relating to the operational management and execution processes. Besides effective execution procedures, the competency of shipboard crews faced with different cargo specifications is also a significant issue. It means the specialized training facilities should be updated to ensure the safely operations on board chemical tankers. Specifically, this paper proposes a hybrid methodology to redesign current ISM code procedure in order to establish an advanced system towards reducing potential hazards for seafarers on board tanker ships. The AHP and FAD methodologies transform industrial know-how into the practical information needed to extend ISM code procedures to the OHSAS 18001:2007 standards in chemical tanker operations. With this in mind the contributions of fuzzy set theory appear especially useful in the management of the high level of incomplete information and vagueness in the system design process. The principle root causes of the real case of a chemical tanker exploding and sinking are linked to the expected contributions of the proposed execution procedure. Integration of other standards (i.e. ISO 9001, IS0 14001, etc.) into ISM code implementation procedure for chemical tanker fleets can be followed as a further research direction. As a further improvement on proposed compliance assessment methodology, a sensitivity analysis for the derived priority weights by AHP can be considered. Moreover, a further research plan would be the prototype application of the developed system in chemical tanker operating companies. Having a global relevance to the chemical processing industry, a similar approach can be followed to prevent occupational accidents by developing enhanced (integrated) safety procedures for land-based chemical plants. Acknowledgement The author gratefully acknowledges the valuable contributions of the referees in improving the content, quality and presentation of the paper. References Arslan, O., Er, I.D., 2008. SWOT analysis for safer carriage of bulk liquid chemicals in tankers. Journal of Hazardous Material 154 (1–3), 901–913.
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Baker, C.C., McCafferty, D.B., 2005. Accident Database Review of Human-Element Concerns: What Do the Results Mean for Classification?. In: Human Factors in Ship Design-Safety and Operation 23–24 February, London. Celik, M., Cebi, S., Kahraman, C., Er, I.D., 2009a. Application of axiomatic design and TOPSIS methodologies under fuzzy environment for proposing competitive strategies on Turkish container ports in maritime transportation network. Expert Systems with Applications 36 (3, Part 1), 4541–4557. Celik, M., 2009a. Designing of integrated quality and safety management system (IQSMS) for shipping operations. Safety Science 47 (5), 569–577. Celik, M., Kahraman, C., Cebi, S., Er, I.D., 2009b. Fuzzy axiomatic design-based performance evaluation model for docking facilities in shipbuilding industry: the case of Turkish shipyards. Expert Systems with Applications 36 (1), 599– 615. Celik, M., 2009b. A hybrid design methodology for structuring an integrated environmental management system (IEMS) in shipping business. Journal of Environmental Management 90 (3), 1469–1475. Chen, S.M., 1998. Aggregating fuzzy opinions in the decision-making environment. Cybernetics and systems: An International Journal 29, 363–376. Eraslan, E., Akay, D., Kurt, M., 2006. Usability ranking of intercity bus passenger seats using fuzzy axiomatic design theory. Lecture Notes in Computer Science 410, 141–148. Erera, A.L., Morales, J.C., Savelsbergh, M., 2005. Global intermodal tank container management for the chemical industry. Transportation Research Part E 41, 551– 566. Haastrup, P., Brockhoff, L., 1990. Severity of accidents with hazardous materials: a comparison between transportation and fixed installations. Journal of Loss Prevention in the Process Industries 3, 395–405. Hetherington, C., Flin, R., Mearns, K., 2006. Safety in shipping: the human element. Journal of Safety Research 37 (4), 401–411. ISO., 2009. The web site of the International Organization for Standardization (ISO).
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Enhancement of occupational health and safety requirements in chemical tanker operations: The case of cargo explosion Metin Celik * Department of Maritime Transportation and Management Engineering, Istanbul Technical University, Tuzla 34940, Istanbul, Turkey
a r t i c l e
i n f o
Article history: Received 6 January 2009 Received in revised form 23 July 2009 Accepted 13 August 2009
Keywords: Chemical tanker operations Occupational health and safety Shipping accidents Fuzzy axiomatic design Analytic hierarchy process
a b s t r a c t Operational precautions for chemical tankers are vitally important in reducing the potential threat to shipboard crew by products carried. This paper enhances the International Safety Management (ISM) code in compliance with Occupational Health and Safety Management Systems (OHSAS 18001:2007) requirements in respect to operational constraints related to chemical tankers. As research methodology, Fuzzy Axiomatic Design (FAD) and Analytic Hierarchy Process (AHP) are referred to redesign the extended ISM code procedure, which identifies key points for occupational accident prevention on board chemical tankers. To illustrate the expected benefits of an extended ISM code procedure, the principle root causes of chemical tanker explosion are also discussed. In particular, the main results of the case study highlight the urgent need to ensure the competency of shipboard personnel and their familiarization with the characteristics of chemical cargos under differing circumstances. The outcomes set out in this paper contribute to regulatory compliance and to the management of occupational health and safety requirements on board chemical tankers. Ó 2009 Elsevier Ltd. All rights reserved.
1. Potential hazards in chemical tanker operations The transport of chemicals represents a significant portion of total worldwide freight (Erera et al., 2005). Therefore, the chemical industry needs to utilize various transportation modes such as air, pipeline, marine, rail, and road. Among these, marine transportation is recognized as a significant network. By carrying chemical products in bulk via specially designed vessels, it is highly important for the sustainability of chemical processing industry. However, maritime transportation is threatened by various hazards such as fire, explosion, and toxic release (Khan and Abbasi, 1999). Furthermore, major catastrophic events involving chemical tankers (Haastrup and Brockhoff, 1990) have threatened human life and the maritime environment. Aside from shipping accidents, the routine operations on board chemical tankers (i.e. cargo handling, tank inspection, gas-freeing, tank cleaning, tank purging, etc.) also have additional risks – especially for seafarers (Arslan and Er, 2008). Experience has pointed out that understanding and controlling these hazards is of vital importance not only in the design and construction stages of chemical tankers but also in their operation processes (Romer et al., 1993; Rao and Raghavan, 1996; Shaluf et al., 2003; Jetlund and Karimi, 2004). Shipping casualties during the transportation of large quantities of liquid bulk chemicals may have acute and chronic effects on both marine * Tel.: +90 216 395 1064; fax: +90 216 395 4500. E-mail address: [email protected] 0925-7535/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.ssci.2009.08.004
habitats and the accommodation and working spaces of tanker ships (Arslan and Er, 2008). Recent innovations in marine technology have reinforced safety precautions (Wang, 2002; Hetherington et al., 2006) which can improve construction and operating systems on board tanker ships. Nevertheless, the familiarization of shipboard crew to different freights is still not qualified according to the physical properties and chemistry of different cargo types (i.e. petrochemical products, coal tar products, alcohols, heavy chemicals, etc.) especially during cargo-handling operations. The serious effects of different cargo related to such characteristics as flammability, toxicity, corrosiveness and self-reaction ought to be monitored by the shipboard crew regularly. All these constraints require technical support for the shipboard crew aboard chemical tankers. Relevance to solutions for these operational issues, responsible managers can follow the specialized procedures based on the operating environment of chemical tankers to ensure an appropriate shore-based and shipboard interface. In addition to operational risks due to cargo characteristics, external pressure by Non-Governmental Organizations (NGOs) and global cargo owner associations have also forced chemical tanker operators to maintain standards at reliable levels due to the potentially extraordinary catastrophic effects of chemical tanker accidents. The International Safety Management (ISM) code provides a fundamental international standard for ensuring safe management and pollution prevention during operation of ships (Glazar, 1998). It is mandatory for passenger ships, oil/chemical
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tankers, gas carriers, bulk carriers, high-speed cargo craft of 500 gross tonnages and upwards, other cargo ships, and mobile offshore drilling units of 500 gross tonnage and upwards. However, it should be recognized that the current implementation of the ISM code cannot appropriately fulfil expectations – especially those directed at enhancing occupational health and safety requirements. This is due to the complexity of chemical tanker operations. The potential threats particular to specific freights also require that those dealing with them can do so with a high level of competence. Specifically, the International Code for the Construction and Equipment of Ships carrying Dangerous Chemicals in Bulk (IBC Code) and The International Maritime Dangerous Goods (IMDG) Code can be cited as specialized regulatory provisions regarding chemical tanker operations. The IBC Code aims mainly to prescribe design and construction standards of ships in order to minimize risks to vessels, crews and the environment while the IMDG Code was developed as an international code for the transport of dangerous goods by sea covering such matters as packing, container traffic, and stowage. When the relevant regulations are analysed in detail, those actually dealing with occupational health considerations appear rare. In addition, actual implementation of these codes creates excessive bureaucrat work within the shipping trade, which in turn triggers reduction of implementation performance at the operational level. In addition to this, continuing shipping casualties and injuries clearly indicate the need for simplified and practical execution procedures in order to ensure fast decision-making – especially in enhancing occupational health and safety requirements aboard chemical tankers. To achieve this, the necessity for a new safety regime covering both operational and occupational aspects needs to be addressed. According to this insight, the following issues should be addressed as they can be expected to arise during management system design: (i) regulatory compliance; (ii) integration; (iii) implementation performance. Hence, this research especially focuses on intensification of ISM code practice in chemical tanker shipping in order to prevent or reduce the effects of hazardous cargo on the shipboard crew. Specifically, this paper follows Fuzzy Axiomatic Design (FAD) and Analytic Hierarchy Process (AHP) methodologies to integrate the recent version of the Occupational Health and Safety Management Systems (OHSAS 18001:2007) requirements into the ISM code to redesign a specialized implementation procedure with high level of compliance. This section motivates the required attitude towards hazardous chemical cargo, the current regulatory framework, and the urgent need for enhancing occupational health and safety requirements on board chemical tankers. Section 2 introduces the theoretical background of FAD and AHP methodologies. In Section 3, the proposed hybrid methodology for coupling the ISM code and OHSAS 18001:2007 requirements by a specific implementation scheme is performed. Following a discussion of the significance of enhanced ISM code procedures on potential chemical tanker casualties, conclusive remarks, and proposals for further research are made.
Axiomatic design theory led theorists to define two design axioms: the independence axiom and the information axiom. The independence axiom states that a good design is one that maintains the independence of the Functional Requirements (FRs). The information axiom states that, among the design alternatives that satisfy the independence axiom, the best alternative is the one that has the lowest information content (Suh, 2007). In recent years, the fuzzy extension of axiomatic design methodology called ‘‘Fuzzy Axiomatic Design” (FAD) (Kulak and Kahraman, 2005a) provides opportunities for solving decisionmaking problems under multiple criteria. Since it is a relatively new tool in decision-making, FAD has had only a few applications (Kulak et al., 2005; Kulak and Kahraman, 2005b; Eraslan et al., 2006; Celik et al., 2009a; Celik, 2009a; Celik et al., 2009b; Celik 2009b). Recently, it has been more extensively dealt with in the literature. In existing applications of FAD methodology, the total information contents of the different alternatives are also utilized for selection, ranking, and strategy-making purposes. FAD has three principal dimensions: system range, decision range, and common range. Fig. 1 illustrates the relations between these parameters in Triangular Fuzzy Number (TFN) form. Principally, the information content of a design is calculated according to the following equation (Kulak and Kahraman, 2005a; Celik et al., 2009a; Celik, 2009a):
I ¼ log2
TFN of system range common area
ð1Þ
In Fig. 1, the corresponding TFN for each dimension is bound to the highest value of membership function – denoted as l(x). After defining the TFN for system range and decision range, a common area appears. The different units for these measures are unified by utilizing a logarithmic base. In the further section of this paper, the conformity levels of ISM code clauses are quantitatively evaluated with respect to the requirements of OHSAS 18001:2007. The total information contents of each clause provide opportunities for redesigning the current implementation procedure of the ISM code to incorporate the existing occupational health and safety requirements. Table 1 illustrates the fuzzy scale for defining FRs
µ (x)
TFNs of System Range
TFNs of Decision Range
a
c
1
x b
d
Common area 2. Background of research methodology
Fig. 1. Definitions of principal dimensions in TFNs forms.
2.1. Theory and practice of FAD The FAD methodology is structured based on axiomatic design principles (Suh, 1990) having the following fundamental concepts: (1) design as a mapping process; (2) design abstraction in the hierarchical structure; (3) design laws in the form of axioms; (4) design equations as notation for representing functional dependencies (Lo and Helander, 2007). In practice, the designers apply the advantages of axiomatic design foundation to improve the design process.
Table 1 Fuzzy scale for defining of FRs. Linguistic terms on conformity degree
TFNs
Clauses at least fully conforming (FC) Clauses at least substantially conforming (SC) Clauses at least partially conforming (PC) Clauses at least low conforming (LC) Closes at least very low conforming (VLC)
(0.8, 1, 1) (0.6, 1, 1) (0.4, 1, 1) (0.1, 1, 1) (0, 1, 1)
M. Celik / Safety Science 48 (2010) 195–203 Table 2 Fuzzy scale for conformity level assessment. Conformity level
TFNs
Very high (VH) High (H) Medium (M) Low (L) Very low (VL)
(0.8, 1, 1) (0.6, 0.9, 0.9) (0.4, 0.7, 0.7) (0.1, 0.5, 0.5) (0, 0.3, 0.3)
Table 3 Saaty’s scale of relative importance. Linguistic judgments
Values
Equal importance Weak importance Strong importance Demonstrated importance Absolute importance Intermediate values between judgments
1 3 5 7 9 2, 4, 6, 8
over relevant requirements as evaluation attributes. Table 2 illustrates the corresponding TFNs for the linguistic terms (Celik 2009b), which are planned to measure conformity levels of ISM code clauses with OHSAS 18001:2007 requirements. 2.2. AHP methodology The AHP is one of the mostly utilized decision-making tools used in comparing a number of alternatives with respect to an overall goal under a multiple criteria decision environment (Saaty, 1980; Saaty, 1986). In addition to ensuring consistent outcomes among problem alternatives, the AHP also leads to obtaining priorities of relevant attributes in a subsequent hierarchic structure. A wide range of theoretical information regarding the mathematical concepts involved in AHP methodology can be found within the contents of previously published research papers (Saaty, 1990; Saaty 1991; Saaty, 1994). Applications of the AHP methodology have appeared in a great number of fields (Golden et al., 1989; Kumar and Vaidya, 2006). In this study, the hierarchic structure of OHSAS 18001:2007 requirements is decomposed and assessed comparatively. Then, the priority weights of each element are computed with respect to the operational constraints of chemical tankers. The Saaty’s scale of relative importance shown in Table 3 (Saaty, 1990) is utilized to prioritize the weights of OHSAS 18001:2007 requirements by considering the potential hazards of operating environments aboard chemical tankers. Specifically, integration of the AHP into research methodology provides priority values for the requirements of OHSAS 18001: 2007. These values subsequently enable a reference point for decision-makers in the design process of integrated management system. Therefore, the function of the AHP is to assist in establishing standardized compliance with chemical tanker operating environment and maritime regulations. 3. Proposed model 3.1. Problem statement The main aim of this study is to ensure the provision of the information required for redesigning ISM code procedures in order to couple them with the OHSAS 18001:2007 requirements under a single implementation scheme. At this point, the hybrid approach with AHP and FAD methodologies provides quantitative outcomes
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over ISM code clauses regarding compliance levels which can be recognized as a decision aid for ensuring a ‘state of the art‘ system redesign process. This means that a high level of compliance between the ISM code and OHSAS 18001:2007 can be achieved by measuring expectations in terms of defining FRs for each clause of the ISM code and weighting the requirements of OHSAS 18001:2007 in respect to the potential hazards aboard chemical tankers. Before performing solution algorithm, current implementation procedure of the ISM code in chemical tanker fleets and the recently updated version of OHSAS 18001:2007 are introduced as technical background information within the following sub-sections entitled: 3.1.1 ISM code Implementation for Chemical Tankers and 3.1.2 Expected Contributions of OHSAS 18001:2007 in Chemical Tanker Environment. 3.1.1. ISM code implementation for chemical tankers Technical analyses of the details of shipping accident statistics (O’Neil, 2003; Baker and McCafferty, 2005) underline the great necessity to improve safety management systems and shore-based organization both in shipping companies ashore and shipboard hierarchy aboard. Thus the ISM code contributes not only to the safe operation of ships and protection of the environment but also critically influences the style of management in a shipping company and improves the entire quality of management resulting in better business outcomes. Therefore, responsible shipping company managers should be fully committed to implementing the ISM code into fleet operational procedures. The ISM code can be divided into two main sections: (1) implementation and (2) certification and verification. These two sections contain a total of 16 clauses. The implementation process of the ISM code is divided into 12 distinct clauses as follows: general (clause 1); safety and environmental protection policy (clause 2); company responsibilities and authority (clause 3); designated person(s) (clause 4); master’s responsibility and authority (clause 5); resources and personnel (clause 6); development of plans for shipboard operations (clause 7); emergency preparedness (clause 8); reports and analysis of nonconformities, accidents, and hazardous occurrences (clause 9); maintenance of the ship and equipment (clause 10); documentation (clause 11); company verification, review, and evaluation (clause 12); certification and periodical verification (clause 13); interim certification (clause 14); verification (clause 15); forms of certificates (clause 16) are the clauses contained within the second part of the ISM code. In the chemical tanker operating process, the contributions of the ISM code practice have seemed especially significant in the development and implementation of operational and emergency plans relevant to chemical tankers. In a broad sense, the plans for tanker operations are prepared in accordance with the following constraints: (1) operational orders; (2) company procedures; (3) ISM code requirements; (4) other regulatory requirements. The ISM code has serious advantages especially regarding the development of vessel emergency plans, the carrying out of emergency shutdowns of chemical cargo operations, in special precautions being taken while carrying out maintenance, in the application of first aid in relation to chemical cargo accidents, in using resuscitation equipment and breathing apparatus, in carrying out safe entry into and rescue from enclosed spaces, and in taking appropriate action in the event of catastrophes such as collision and chemical spillage. However, the links for sustaining the occupational healthcare and safety precautions regarding the varying hazards of cargo in different operations are not clearly identified. Therefore, the ISM code implementation procedure should be extended operationally to clearly identify typical emergency problems and potential hazards on board chemical
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tankers in order to be able to promptly initiate appropriate corrective/preventive actions. 3.1.2. Expected contributions of OHSAS 18001:2007 aboard chemical tanker Following the research methodology, the requirements of OHSAS 18001:2007 can be considered as a hierarchical decision structure (ISO, 2009). Then the priority weights of each requirement can be assigned based on AHP. In the first level of hierarchy, the general requirements-4.1, policy-4.2, planning-4.3, implementation and operation-4.4, checking-4.5, and management review-4.6, denoted by R1, R2, R3, R4, R5, R6 are the main requirements of OHSAS 18001:2007. In the planning stage, hazard identification, risk assessment and determining controls-4.3.1 (R31), legal and other requirements-4.3.2 (R32), objectives and programs-4.3.3 (R33) are the sub-requirements. As the most significant process of OHSAS 18001:2007 bodies, the implementation and operation stages include the following sub-requirements: resources, roles, responsibility, accountability and authority-4.4.1 (R41), competence, training, awareness-4.4.2 (R42), communication, participation, and consultation-4.4.3 (R43), documentation-4.4.4 (R44), control of document4.4.5 (R45), operational control-4.4.6 (R46), emergency preparedness and response-4.4.7 (R47). In addition, performance measurement and monitoring-4.5.1 (R51), evaluation of compliance-4.5.2 (R52), incident investigation, nonconformity, corrective and preventive action-4.5.3 (R53), control of records-4.5.4 (R54), internal audit-4.5.5 (R55) are the sub-attributes of checking-4.5 procedures. Table 4 summarizes the requirements of OHSAS 18001:2007. In practice, implementation of the OHSAS 18001:2007 requirements can be regarded as challenges for reducing occupational hazards and improving working conditions especially in the cases of the following special processes and duties on board chemical tankers: (1) enclosed space and cargo tank entries; (2) working on pipelines and pressurized pipes; (3) testing of cargo pump operations and functionality; (4) operations on and maintenance of cargo heating system; (5) testing of cargo valves and houses on board ship; (6) calibration of toxic gas detection, explosive meter, and oxygen meter. Furthermore, the requirements of clause-4.3.1 enable the definition of hazards associated with chemical cargoes including understanding of the types of hazards and their causes, safety and hazard minimization procedures used on chemical tankers, potential health hazards of various chemical cargoes, basic toxicological terminology, routes of entry of toxins to the human
body, and other safety related matters. The integrated execution plan of the ISM code and OHSAS 18001:2007 standards on board chemical tankers deals with the serious drawbacks in various procedures such as ventilation of spaces, cargo related processes, emergency preparedness. However, both managers in the shorebased organization and shipboard personnel require a welldesigned implementation procedure to increase the benefits from extended ISM code procedure. 3.2. Performing of model algorithm The mathematical algorithm of the proposed hybrid approach is performed at five stages as follows: (1) computing the priority weights on OHSAS 18001:2007 requirements; (2) assigning judgments over FRs and ISM code clauses; (3) performing of fad; (4) deriving final outcomes; (5) utilization of model outcomes for redesigning of ISM code procedure. 3.2.1. Stage 1: computing the priority weights on OHSAS 18001:2007 requirements The AHP methodology is performed over the hierarchic structure of OHSAS 18001:2007 requirements. The group aggregation of the expert judgments is inserted into the Superdecisions Software. The expert profile consists of representatives from maritime professional and administrative organizations, responsible managers and quality executives from ship management companies. In detail, the expert judgements recognize the opinions of professional managers and marine superintendents (especially from technical departments of shipping companies) who have a seagoing background and professional execution experience. A meeting was held to incorporate their judgements into the model by group consensus. The aggregate judgements then provided the required input data for the AHP algorithm. After structuring the decision matrix, the priority weights on the requirements of OHSAS 18001:2007 are then computed based on AHP by Superdecisions Software. Tables 5 and 6 illustrate the priority weights on attributes according to different levels of hierarchy. The derived values can be recognized as reference points in the system design of an extended ISM code procedure. It means that the priority values of standard requirements are utilized to decide the importance levels of each requirement. The priority weights on attributes allow the decision-makers to identify the significant points of management system
Table 4 Requirements of OHSAS 18001:2007. OHSAS 18001:2007 Main requirements
Code
Sub-requirements
Code
General requirements (4.1) Policy (4.2)
R1 R2
Planning (4.3)
R3
Implementation and operation (4.4)
R4
Checking (4.5)
R5
Management review (4.6)
R6
NA NA Hazard identification, risk assessment and determining controls (4.3.1) Legal and other requirements (4.3.2) Objectives and programs (4.3.3) Resources, roles, responsibility, accountability and authority (4.4.1) Competence, training, awareness (4.4.2) Communication, participation, and consultation (4.4.3) Documentation (4.4.4) Control of document (4.4.5) Operational control (4.4.6) Emergency preparedness and response (4.4.7) Performance measurement and monitoring (4.5.1) Evaluation of compliance (4.5.2) Incident investigation, nonconformity, corrective and preventive action (4.5.3) Control of records (4.5.4) Internal audit (4.5.5) NA
– – R31 R32 R33 R41 R42 R43 R44 R45 R46 R47 R51 R52 R53 R54 R55 –
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priorities of different chemical tanker operating companies (i.e. company vision/mission, operating policy, etc.). Therefore, further modifications regarding implementation of ISM code clauses can be initiated with respect to the occupational health and safety policies of chemical tanker shipping firms. According to this insight, the AHP provides the responsible executives with great flexibility in system design. It means that it is possible to refer to different ranking orders of the ISM code clauses to comply with the OHSAS 18001:2007 requirements.
Table 5 Computed priority weights for main attributes. Attributes (requirements)
Normalized values
Limiting values
R1 R2 R3 R4 R5 R6
0.165 0.246 0.117 0.213 0.118 0.141
0.114 0.170 0.081 0.147 0.082 0.097
3.2.2. Stage 2: assigning judgments over FRs and ISM code clauses The second stage of the solution algorithm requires assigning the consistent judgments to identify the FRs for the focused system. Table 7 illustrates the expectations of the different maritime trade executive groups for the requirements of the OHSAS 18001: 2007 standardization system for chemical tanker operations. The assigned TFN values indicate the expectations of conformity level among the ISM code clauses and OHSAS 18001 requirements. In addition, relevant judgments are required for the different clauses of the ISM code in order to enable their classification with respect to their conformity levels. Hence, the linguistic terms in TFNs are assigned for each clause of the ISM code in Table 8. Principally, the assigned judgements reflect the ideas regarding conformity levels of different clauses for each requirement of the OHSAS 18001:2007.
Table 6 Computed priority weights for sub-attributes. Sub-attributes (Sub-requirements)
Normalized values
Limiting values
R31 R32 R33 R41 R42 R43 R44 R45 R46 R47 R51 R52 R53 R54 R55
0.464 0.281 0.255 0.167 0.251 0.093 0.070 0.087 0.146 0.187 0.259 0.207 0.219 0.176 0.138
0.037 0.023 0.021 0.025 0.037 0.014 0.010 0.013 0.021 0.027 0.021 0.017 0.018 0.014 0.011
3.2.3. Stage 3: performing of FAD First, aggregation of the judgements given in Table 7 is performed by following one of the common aggregation approaches proposed by Chen (1998). The aggregated results of the linguistic judgments over FRs in TFNs form are illustrated in Table 9.
requirements of OHSAS 18001:2007 for chemical tanker operations. As previously mentioned, the revealed outcomes from AHP provide a decision aid in advanced management/execution/operating system design. This may influence the results according to the
Table 7 FRs over OHSAS 18001:2007 requirements. Maritime expert groups
Management system requirements (OHSAS 18001:2007) R1
Ship managers Standardization system executives Administrative organizations
PC LC LC
R2
R3
PC SC PC
R4
R5
R6
R31
R32
R33
R41
R42
R43
R44
R45
R46
R47
R51
R52
R53
R54
R55
SC SC PC
PC SC PC
PC SC SC
PC SC PC
PC PC PC
LC PC PC
LC PC VLC
VLC PC PC
PC SC SC
SC SC PC
SC PC LC
PC LC PC
LC PC SC
PC PC PC
PC LC PC
LC PC LC
Table 8 Judgments on conformity levels of ISM code clauses. ISM code
Management system requirements (OHSAS 18001:2007) R1
Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
M M L L L L L L L L L L L VL L L
R2
H H M L L M L L L L L L L VL L L
R3
R4
R5
R6
R31
R32
R33
R41
R42
R43
R44
R45
R46
R47
R51
R52
R53
R54
R55
M M H M M L H L M M M H L VL M VL
L M M L L M M M M L M M M M M VL
M H H M M M H M M H M M L L VL VL
L L VH VH VH H H M M M L M L VL L VL
L L VH H H VH H H L H L M L M L L
M H H M H H H M L M M L M M L VL
VL L M M H L M L L L VH L M L VL L
VL VL M VL M VL M M L M VH L M VL VL VL
L M H H H H VH VH M M M M L L L VL
L M VH M VH H VH M M VH M M L M M VL
M L H M H M H L M M M H VL VL L L
L L H M H L H L L L M L VL VL L VL
L VL H M H M M L VH M L M VL L L VL
L VL M M M VL M VL L L VH L L VL VL M
VL VL H M H L L M M M L VH VL VL L VL
VL VL H M VH L L M M M L VH L VL VL VL
200
Table 9 Aggregated FRs values in TFNs form. Management system requirements (OHSAS 18001:2007) R2
R1
(0.197, 1, 1)
(0.466, 1, 1)
R3
R4
R5
R6
R31
R32
R33
R41
R42
R43
R44
R45
R46
R47
R51
R52
R53
R54
R55
(0.534, 1, 1)
(0.466, 1, 1)
(0.534, 1, 1)
(0.466, 1, 1)
(0.400, 1, 1)
(0.303, 1, 1)
(0.164, 1, 1)
(0.271, 1, 1)
(0.534, 1, 1)
(0.534, 1, 1)
(0.368, 1, 1)
(0.303, 1, 1)
(0.368, 1, 1)
(0.400, 1, 1)
(0.303, 1, 1)
(0.197, 1, 1)
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Table 10 Distribution of information contents over ISM code clauses. ISM code
Management system requirements (OHSAS 18001:2007) R1 0.165
Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause Clause
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
0.904 0.904 1.810 1.810 1.810 1.810 1.810 1.810 1.810 1.810 1.810 1.810 1.810 4.515 1.810 1.810
R2 0.246
0.110 0.110 1.545 7.495 7.495 1.545 7.495 7.495 7.495 7.495 7.495 7.495 7.495 INF 7.495 7.495
R3 0.117
R4 0.213
R5 0.118
R6 0.141
R31 0.464
R32 0.281
R33 0.255
R41 0.167
R42 0.251
R43 0.093
R44 0.070
R45 0.087
R46 0.146
R47 0.187
R51 0.259
R52 0.207
R53 0.219
R54 0.176
R55 0.138
2.350 2.350 0.174 2.350 2.350 INF 0.174 INF 2.350 2.350 2.350 0.174 INF INF 2.350 INF
7.490 1.544 1.544 7.490 7.490 1.544 1.544 1.544 1.544 7.490 1.544 1.544 1.544 1.544 1.544 INF
2.350 0.174 0.174 2.350 2.350 2.350 0.174 2.350 2.350 0.174 2.350 2.350 INF INF INF INF
7.490 7.490 0.000 0.000 0.000 0.110 0.110 1.544 1.544 1.544 7.490 1.544 7.490 INF 7.490 INF
4.585 4.585 0.000 0.123 0.123 0.000 0.123 0.123 4.585 0.123 4.585 0.737 4.585 0.737 4.585 4.585
0.755 0.178 0.178 0.755 0.178 0.178 0.178 0.755 2.840 0.755 0.755 2.840 0.755 0.755 2.840 INF
3.767 1.569 0.964 0.964 0.271 1.569 0.964 1.569 1.569 1.569 0.000 1.569 0.964 1.569 3.767 INF
8.065 8.065 0.790 8.065 0.790 8.065 0.790 0.790 2.480 0.790 0.000 2.480 0.790 8.065 8.065 8.065
INF 2.350 0.174 0.174 0.174 0.174 0.000 0.000 2.350 2.350 2.350 2.350 INF INF INF INF
7.291 2.350 0.000 2.350 0.000 0.174 0.000 2.350 2.350 0.000 2.350 2.350 INF 2.350 2.350 INF
0.722 3.863 0.138 0.722 0.138 0.722 0.138 3.863 0.722 0.722 0.722 0.138 INF INF 3.863 3.863
2.840 2.840 0.178 0.755 0.178 2.840 0.178 2.840 2.840 2.840 0.755 2.840 INF INF 2.840 INF
3.862 INF 0.138 0.722 0.138 0.722 0.722 3.862 0.000 0.722 3.862 0.722 INF 3.862 3.862 INF
4.585 INF 0.737 0.737 0.737 INF 0.737 INF 4.585 4.585 0.000 4.585 4.585 INF INF 0.737
INF INF 0.178 0.755 0.178 2.840 2.840 0.570 0.755 0.755 2.840 0.000 INF INF 2.840 INF
4.515 4.515 0.248 0.904 0.000 1.810 1.810 0.626 0.904 0.904 1.810 0.000 1.810 4.515 4.515 4.515
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Based on the FAD algorithm, the information contents are computed using the Eq. (1). Distribution of information contents over ISM code clauses. This is illustrated in Table 10.
Table 11 Ranking of ISM code clauses. Rank
ISM code
P
1 2 3 4 5 6 7 8
Clause Clause Clause Clause Clause Clause Clause Clause
0.882 2.682 2.861 2.899 3.145 3.175 3.401 3.830
3 5 12 7 10 4 9 11
I
3.2.4. Stage 4: deriving final outcomes The weighted information contents over ISM code clauses support the final outcomes for initiating the redesign process of ISM code procedure. Based on the results, eight of the clauses are compliance with the OHSAS 18001:2007 requirements while those remaining have considerable problems in coupling with the ISM
INITIATE: Motivate to redesign the ISM Code procedure to comply with the OHSAS 18001:2007 requirements Pre-identification of potential hazards for chemical tanker operations
Establish the ISM Code-Clause 3 with respect to Clause 4.4.1 and Clause 4.4.6 of OHSAS 18001:2007 Maintain the requirements of the ISM Code-Clause 5 with respect to Master’s authority and responsibility in terms of Clause 4.3.2 of OHSAS 18001:2007 Yes
Yes
Does it satisfy with the Clause 4.4.7 of OHSAS 18001:2007?
No
Yes
Review the new procedure in accordance with the ISM Code-Sub clause 1.4 and Clause 4.3.1 of OHSAS 18001:2007
Prepare draft requirements of audit process for operational safety complying with ISM Code-Clause 12 and Clause 4.3.1 of OHSAS 18001:2007
No Does it satisfy with the Clause 4.3.3 of OHSAS18001:2007?
Implement the ISM Code-Clause 7 requirements
No
Reassure the ISM Code-Clause 3 & Clause 5
Plan maintenance requirements of shipboard technical system with respect to ISM Code-Clause 10 Implement performance measurement process with respect to Clause 4.3.1 of OHSAS 18001:2007. Implement shipboard emergency procedure for the ISM Code-Clause 8
Does it constitute with DPA execution activities?
Implement ISM Code-Clause 9 and Clause 4.5.3 of OHSAS 18001:2007 under a unique procedure
No
Yes Implement ISM Code-Clause 12 and Clause 4.5.2 & 4.5.5 of OHSAS 18001:2007 under a unique procedure
Yes No Does it satisfy with the 4.4.6, 4.5.2 of OHSAS18001:2007? END: Establish extended ISM Code procedure on OHSAS 18001:2007 requirements
No
Yes Does it satisfy shipboard operations Clause 4.4.6 of OHSAS 18001:2007?
Review the satisfaction for ISM Code-Clause 1, 2, 6
No
Satisfy?
Execute the documentation process via Clause 11, Clause 15, Clause 13, Clause 14, and Clause 16 separately
Yes
Fig. 2. Extended implementation procedure on ISM code.
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code. Table 11 gives the ranks of highly conformed ISM code clauses. Nevertheless, the values of total information contents for clause 1, clause 2, clause 6, clause 8, clause 13, clause 14, clause 15, and clause 16 are infinite. The next issue is to utilize those values in the design of extended ISM code procedure. 3.2.5. Stage 5: utilization of model outcomes for the redesigning of ISM code procedure It is planned to utilize the outcomes of the FAD methodology for the implementation of system redesign of ISM code procedures to enhance the occupational health and safety level in chemical tanker operations. Based on the model outcomes, clause 3 has the highest conformity among the ISM code clauses. The assigned rank in Table 11 can be utilized as a decision aid for re-structuring a new implantation procedure of ISM code for chemical tankers operations. Finally, the extended implementation procedure of the ISM code is illustrated in Fig. 2. The extended structure of the ISM code ensures the integration of the special requirements for chemical tanker operations, thus enhancing the occupational health and safety precautions and reducing the possibility for catastrophic failures aboard ships. 4. Case study: linking with chemical tanker accident case 4.1. Introduction to accident case In this section, the strengths and expected contributions of the extended ISM code procedure based on occupational health and safety requirements are considered by studying an a case where a chemical tanker exploded and sank. In 2004, the chemical tanker Bow Mariner caught fire and exploded in the Atlantic Ocean while the crew was engaged in cleaning residual methyl tert-butyl ether (MTBE) from the cargo tank (U.S.C.G, 2005). This had fatal consequences for 21 of the 27 man crew. The environmental impact was considerable as great quantities of MTBE, Ethyl Alcohol, heavy fuel oil, and diesel fuel were released. Briefly, the accident investigation report identified the cause of this accident as being ignition of a fuel/air mixture, either on deck or in the cargo tanks, that was within its flammable limits. The dominant casualty factors had mainly to do with shortcomings in shore-based support and with operator failures on board the chemical tanker. More detailed technical information regarding the different chemical cargoes (i.e. ethyl alcohol, methyl tert-butyl ether) which were present in various tanks is given in Table 12. The basic principal cause of the accident was the lack of awareness and the incompetence of crews responsible for the cargo. A wrong decision was made t open cargo tanks that previously held MTBE thus permitting the accumulation heavier than air flammable vapours on deck. It diluted the fuel-rich atmosphere in the cargo tanks with oxygen, bringing them into the flammable range. Then, the explosion occurred on board due to ignition by one of a number of possible sources considered: cell phone, sabotage, smoking, electrostatic discharge, mechanical spark, or electrical source. Table 12 Properties of ethyl alcohol and methyl tert-butyl ether. Properties
Chemical cargo Ethyl alcohol
UN number Chris code IMO pollution category Grade flash point Specific gravity Vapour density (air = 1.0) Solubility in water
Methyl tert-butyl ether
1170 2398 EAL MBE II D C – flammable liquid 65 °F 14 °F 0.79 0.74 3.1 1.6 Complete Complete
Furthermore, the accident investigation report found certain evidence regarding procedures and regulatory concept: (1) noncompliance with ISM code practice; (2) implementation shortfalls of the safety, quality and environmental protection management system (SQEMS) procedures on board; (3) insufficiency of the inert gas system (IGS) operations; (4) misperception in tank cleaning procedures; (5) misperception in procedures for gas release after tank cleaning. 4.2. Expected contributions of extended ISM code procedure Following the casualty analysis, the paper explores the potential benefits of the extended ISM code procedure. Recalling Fig. 2, the extended ISM code procedure initiates the shipping company responsibility and authority (ISM code-clause 3) in respect to the operational control (sub-requirements 4.4.6 of OHSAS 18001:2007) specific to the potential hazards of chemical tanker operations. This gives a great advantage to shore-based organization and shipboard crews in following safety procedures in the cargo tank cleaning and gas release processes. Based on the investigation report, this accident points to a high level of decision error by the responsible crew members, (especially masters and chief officer), on board. In the extended ISM code procedure, defining a master’s responsibility and authority (ISM code-clause 5) in accordance with legal and other requirements (sub-requirement 4.3.2 of OHSAS 18001:2007) ensures fully compliance of specially designed safety and occupational health procedures for chemical tanker operations. Furthermore, monitoring this process based on sub-requirements-4.3.3 of OHSAS 18001:2007 clearly satisfies especially the need for adequate communication – which was found to be so insufficient in the case discussed. During the preparation of procedures for shipboard operations (ISM code-clause 7), taking emergency preparedness and response (sub-requirements 4.4.7 of OHSAS 18001:2007) into account has vital importance in maintaining occupational health and safety requirements. In the case analysed, a number of crew members died due to the improper application of this critical emergency response. The following of maintenance and emergency procedures, is assigned by the extended ISM code procedure to a Designed Person Ashore (DPA). This provides for a well-controlled and sustainable ship-shore interface in the execution procedure. In the case of this accident, technical support for the newly embarked shipboard crews (chief officer) was severely limited. This was also the case for shipboard personnel competency regarding the properties of the chemical cargo which was the responsibility of the DPA and other technical managers. At this point, the extended ISM code directly assigns the DPA the duty of ensuring the capability of shipboard personnel regarding specific elements of chemical tanker operations. Finally, reviewing the company verification (ISM code-clause 12) for the entire procedure – based on the operational control constraints (sub-requirements 4.4.6 of OHSAS 18001:2007) – is another key point of the proposed system. It appears quite clear that the extended ISM code has strict safety barriers to reduce hazardous occurrences and the potential for catastrophes. The case study addressed the expected contributions of extended ISM Code compliance with OHSAS requirements on board chemical tankers. In particular, the consequences of personnel incompetence in relation to the characteristics of chemical cargos were strongly emphasised; moreover, the potential utility of the proposed extended ISM code/OHSAS 18001:2007 system is clearly introduced. In contrast, the current content of the ISM code enables a broad procedural support of crewmembers to safety and environment-related threats. However, the concept underlying this paper is the extension of this procedural support to occupational health and safety requirements. Thus the key target group of the extended ISM code procedure is shipboard crewmembers. In addition,
M. Celik / Safety Science 48 (2010) 195–203
shore-based managers are responsible for ensuring the transformation of redesigned ISM code procedures (specific to chemical tankers) into useful knowledge (i.e. providing operational decision aid) especially for cargo-handling, tank inspection, gas-freeing, tank cleaning, and tank purging operations. Enhancement of shipboard occupational health/safety requirements and their integration by OHSAS 18001:2007 requirements into the existing ISM code framework is the core idea which is reasonably congruent with the case outlined in this paper. This supports the thesis that the enhanced ISM code procedure has a great potential/capability for reducing probable root causes leading to disasters such as the cargo explosion case discussed. When benchmarked with the existing ISM code framework, the practical advantages of the OHSAS 18001-extended ISM code can clearly be seen. 5. Concluding remarks and further research proposals Chemical tanker operations require a high level of safety and environmental-related precautions when relatively compared with other types of merchant ships. Various human-system interactions have occurred during the loading, discharging, tank cleaning, ventilating, and condition monitoring processes of chemical cargo. Reducing catastrophes in chemical tankers requires implementing urgent strategies and fast decision-making procedures relating to the operational management and execution processes. Besides effective execution procedures, the competency of shipboard crews faced with different cargo specifications is also a significant issue. It means the specialized training facilities should be updated to ensure the safely operations on board chemical tankers. Specifically, this paper proposes a hybrid methodology to redesign current ISM code procedure in order to establish an advanced system towards reducing potential hazards for seafarers on board tanker ships. The AHP and FAD methodologies transform industrial know-how into the practical information needed to extend ISM code procedures to the OHSAS 18001:2007 standards in chemical tanker operations. With this in mind the contributions of fuzzy set theory appear especially useful in the management of the high level of incomplete information and vagueness in the system design process. The principle root causes of the real case of a chemical tanker exploding and sinking are linked to the expected contributions of the proposed execution procedure. Integration of other standards (i.e. ISO 9001, IS0 14001, etc.) into ISM code implementation procedure for chemical tanker fleets can be followed as a further research direction. As a further improvement on proposed compliance assessment methodology, a sensitivity analysis for the derived priority weights by AHP can be considered. Moreover, a further research plan would be the prototype application of the developed system in chemical tanker operating companies. Having a global relevance to the chemical processing industry, a similar approach can be followed to prevent occupational accidents by developing enhanced (integrated) safety procedures for land-based chemical plants. Acknowledgement The author gratefully acknowledges the valuable contributions of the referees in improving the content, quality and presentation of the paper. References Arslan, O., Er, I.D., 2008. SWOT analysis for safer carriage of bulk liquid chemicals in tankers. Journal of Hazardous Material 154 (1–3), 901–913.
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