Section 2 System and equipment categories
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Submarine Assurance Framework, July 2022 - Volume 1 Submarine Assurance - Part 4 Whole Boat Requirements - Chapter 3 Requirements for Systems - Section 2 System and equipment categories

Section 2 System and equipment categories

2.1 Functional objectives

2.1.1  Systems, equipment and components shall be assigned a safety criticality category based on the criticality of their function in normal, abnormal and emergency operating conditions. The integrity of the systems, equipment and components shall be commensurate with their assigned safety criticality category.

2.2 Performance requirements

2.2.1 The categorisation of systems, equipment and components shall be carried out in accordance with a categorisation process which fulfils the aims of this Section.

2.2.2 The categorisation process shall take into account both the risk assessment requirements and the whole boat requirements in Vol 1, Pt 1, Ch 2, 4 Framework processes.

2.2.3 The categorisation process shall be agreed by LR and all stakeholders.

2.2.4 The designer shall list all systems, equipment and components on the submarine and establish their category.

2.2.5 The categorisation process shall define the categories in relation to safety criticality and the procedure by which systems are assigned to those categories.

2.2.6 The process shall recognise system dependencies and the contribution of systems to submarine functions.

2.2.7 The process shall recognise the potential impact of the systems, equipment and components on embarked persons.

2.2.8 Equipment and components shall be assigned the same category as the system of which they are a part. Equipment and components assigned a lower category than the system of which they are a part, shall be fully justified, with a risk assessment, safety argument and hazard analysis.

2.2.9 Additional specification requirements such as susceptibility, military functions or performance requirements for particular systems, equipment and components may result in those systems, equipment and components being assigned to a higher category in agreement with relevant stakeholders.

2.2.10 Any justification for assigning equipment and components to a lower category than the system of which they are a part based on redundancy, shall include assessments of capacity, diversity, reliability and failure modes, including common modes of failure, for all redundant equipment and components in the system and the system itself, relative to the whole boat risk assessment and safety argument.

2.2.11 Policies, procedures and requirements for the design and construction of systems, equipment and components, their verification and validation, shall recognise and take account of safety criticality categories and provide for the required integrity.


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