Tool Qualification

Tool qualification is the process of systematically gathering objective evidence to demonstrate that a software tool is suitable for its intended use in developing a specific safety-critical system. It also ensures that the risk of tool malfunction causing harm is acceptably low.

Human lives are at risk when unqualified software tools are employed. Proper qualification reduces the risk that these tools produce unreliable outputs that jeopardize safety. Using unqualified tools can lead to severe, potentially deadly outcomes, reinforcing the critical need for rigorous tool qualification in safety-critical applications.

No, qualification is typically required only for tools where a malfunction could potentially introduce errors into the final product or fail to detect existing errors, and where such tool-induced errors are not sufficiently mitigated by other development processes. The safety standard ISO 26262 uses the Tool Confidence Level (TCL) which is established during the Tool Classification process. Higher TCLs necessitate more rigorous evidence, possibly leading to the need for formal qualification.

Many safety-critical industries require rigorous software tool qualification to ensure that all systems perform reliably and securely. The specific requirements are often dictated by international standards, which guide the verification, validation, and overall quality assurance of the tools used in development.

Here are some examples:

• Automotive Industry, ISO 26262: This standard governs functional safety in road vehicles. It mandates the use of qualified software tools during the development of automotive systems to avoid failures that could lead to accidents.

• Cybersecurity in Automotive, ISO/SAE 21434: It is the leading cybersecurity standard for the automotive industry, defining requirements for securing vehicle software, hardware, and networks from cyber threats.

• General Functional Safety, IEC 61508: It is the foundational standard for functional safety across all industries, establishing a risk-based approach to system reliability.

• Aerospace Industry, DO-178C: While not an ISO standard, it is the primary guideline for the development of airborne software used in aircraft systems, supported by DO-330 (Software Tool Qualification Considerations), which provides the detailed framework and guidance for qualifying these tools.

• Industrial Safety, IEC 61511 & ISO 13849: It applies principles specifically to industrial process control systems, such as chemical plants, oil refineries, and manufacturing.

• Medical Device Industry, ISO 62304: Focused on the software lifecycle processes for medical device software, this standard requires that the tools used for software development and maintenance are qualified according to the risk associated with their use.

• Railway and Transit Systems, IEC 61508: This is a generic standard for functional safety of electrical, electronic, and programmable electronic safety-related systems. It forms the basis for more specific standards in various industries, including rail.

• ISO/PAS 8800 (Under Development): A new ISO standard for AI safety in automotive, defining how AI-based software should be tested, verified, and validated for safety-critical applications.

Tool qualification is about demonstrating that a tool is suitable for use in a specific safety-critical project, based on its intended use and context. In contrast, certification serves to assure a broader audience, such as customers, regulators, or third-party assessors, that the tool has been developed and verified according to recognized, rigorous development and quality assurance processes, making it generally trustworthy for safety-related applications.

The certification is the approval from a certification body like TÜV SÜD confirming that the tool complies with a given standard.