・ The hazard identification element in the FSAs encapsulates the proactive aspect of rule development under the FSA approach. Through the use of systematic, team-based techniques, it enables hazards to be identified and risk control options proposed, before they result in accidents.
・ DNV's internal FSA guideline will help solve the problem of achieving consistency in the use of FSA among a large organisation.
2.4 Acceptance Criteria for FSA Based Ship Rules
DNV's corporate objective is to safeguard life, property and the environment. Therefore, the fundamental objective of DNV's rules is ensuring that ships have an acceptable level of safety in respect of life, property and the environment. What is meant by "acceptable level of safety" is defined by risk acceptance criteria.
Risk acceptance criteria are the standards that define whether the risks estimated to arise on the ship are acceptable. In other words, they answer questions such as "How safe is safe enough?" or "What is a reasonably practicable risk control option?" In deciding what is acceptable (and to whom) DNV takes account of not only of the interests of ship owners, but also of its wider social role in protecting the public and the environment.
DNV is in the process of developing risk acceptance criteria for its ship rules, and the following should be regarded as proposals that need further evaluation and may be revised in due course. Such acceptance criteria need to be discussed within the industry and over time need to form the basis for a set of common criteria widely accepted by regulators in the maritime area.
DNV's main mandatory class notation is +1A1, intended to ensure that all ships meet a basic common standard of safety. DNV consider an acceptable level of safety for +1A1 Class will require that:
・ Individual risks of death for crew, passenger and members of the public shall meet defined acceptance criteria (Table 1). For example, the individual risk to crew members shall not exceed 10-3 per year, i.e. a 1 in 1000 chance per year of death in an accident on the ship. These are based on acceptance criteria that are widely used in several industries [5].
・ In addition risks shall be made "as low as reasonably practicable" (ALARP) by adopting cost-effective measures protecting life, third-party property and the environment. This includes any measures that give a positive net benefit in reducing costs of damage, if risk to life is excluded. Alternatively, it includes any measures whose implied cost per averted fatality (ICAF) is less than US $3 million. These are based on values used for decision-making in a recent trial application of FSA at IMO [6].
Maximum tolerable risk for crew members
10-3 per person year
Maximum tolerable risk for passengers
10-4 per person year
Maximum tolerable risk for public ashore
10-4 per person year
Negligible risk
10-6 per person year
These acceptance criteria for +1A1 Class do not take account of any benefit that rules may have in protecting the ship itself, except where this also helps protect life or prevent environmental damage. Rules that protect the ship itself from damage or delay will be covered by different acceptance criteria for voluntary class notations. Voluntary class notations are assigned to vessels with specific operational or trade characteristics and may give more exacting standards of human safety and environmental protection, suitable for owners who wish to demonstrate performance in these areas considerably above the world-wide minimum.
3. EXAMPLE RESULTS
3.1 Generic Ship FSAs
The first requirement in applying the above approach is to establish the baseline risks on different types of ship, and show whether they meet the individual risk acceptance criteria. Figure 2 shows the results of DNV's analysis of individual risks for crew on selected generic ship types, expressed in terms of the annual risk of death for average crew members. It shows that all types meet the proposed criteria, and lie in the ALARP range. This important conclusion helps justify the surprising lack of emphasis on risk acceptance criteria in the IMO guideline, because it shows that the cost-benefit evaluation of risk control options is the most important factor determining the overall acceptability of risks.
In order to show the benefits of risk reduction options, it is necessary to establish the breakdown of the observed risks, and to convert them into monetary units. Figure 3 shows the results of DNV's analysis of the total risks on oil tankers, expressed in terms of the average annual cost of accidents. This figure includes costs of accident to the ship, as well as to people, other property and the environment, but these components can readily be separated for the cost-benefit analysis of individual rules.
