What is ISO 26262:2011?
World over, with the ever increasing use of automotive, their safety considerations are drawing increasing focus related to their design and functional aspects and are becoming more regulated. Automotive industry is adopting standardization and is developing a set of globally acceptable practices for designing and testing of automotive products / components and systems. There have been efforts made by ISO towards continual improvement in this direction.
Increasing complexity throughout the automotive industry is resulting in increased efforts to provide safety-compliant systems. It is a challenge of the automotive industry to test and validate systems like throttle-by-wire etc. The technical state of the art is the highest level of development of a device or process at a particular time.
ISO 26262 : 2011 is has been launched as an international standard that addresses safety aspects of the automotive electrical and E/E systems. This standard is a derivative of IEC 61508 standard the generic functional safety standard for electrical and electronic (E/E) systems. Objective of ISO 26262 is to provide a unifying safety standard for all automotive E/E systems.
Implementing ISO 26262 allows leveraging a common standard to measure how safe a system will be in service. It also provides the ability to reference specific parts of your system because of a common vocabulary provided by the standard. This falls in line with other safety-critical application areas; a common standard provides a way to measure how safe your system is.
Key Components of ISO 26262
ISO 26262 uses a system of steps to manage functional safety and regulate product development on a system, hardware, and software level.
The ISO 26262 standard provides regulations and recommendations throughout the product development process, from conceptual development through decommissioning. It details how to assign an acceptable risk level to a system or component and document the overall testing process. In general, ISO 26262:
- Provides an automotive safety lifecycle (management, development, production, operation, service, decommissioning) and supports tailoring the necessary activities during these lifecycle phases
- Provides an automotive specific risk-based approach for determining risk classes (Automotive Safety Integrity Levels, ASILs)
- Uses ASILs for specifying the item’s necessary safety requirements for achieving an acceptable residual risk.
- Provides requirements for validation and confirmation measures to ensure a sufficient and acceptable level of safety being achieved
Automotive Safety Lifecycle
Ten volumes make up ISO 26262. It is designed for series production cars, and contains sections specific to automotive. For instance, section 7 of ISO 26262 gives specific safety requirements for production, operation, service, and decommission.
The ISO 26262 automotive safety lifecycle describes the entire production lifecycle. This includes the need for a safety manager, the development of a safety plan, and the definition of confirmation measures including safety review, audit, and assessment. These requirements are intended to be used for the development of the E/E systems and elements. This paper mainly focuses on the development section of the lifecycle. The development section of ISO 26262 includes defining the system, system design, functional safety assessment, and safety validation.
Automotive Safety Integrity Level (ASIL)
The ASIL is a key component for ISO 26262 compliance. The ASIL is determined at the beginning of the development process. The intended functions of the system are analyzed with respect to possible hazards. The ASIL ask the question, “If a failure arises, what will happen to the driver and associated road users?”
The estimation of this risk, based on a combination of the probability of exposure, the possible controllability by a driver, and the possible outcome’s severity if a critical event occurs, leads to the ASIL. The ASIL does not address the technologies used in the system; it is purely focused on the harm to the driver and other road users.