There are organizations that are small enough to follow an informal or even undocumented process and still produce a product of sufficient quality to meet market needs.  When these organizations attempt to develop a safety product, they inevitably fall short of meeting the requirements of IEC 61508.  A formalized process that is reviewed and approved, along with project phase deliverables, are a major focus of the standard.

It can be hard to get buy-in from the development team…they just want to get something done.  As a starting point, you have to put some infrastructure in place.  ISO 9000 compliance is a good place to start, because a good quality management system (QMS) is a perfect foundation for a safety development process.  This is a basic “say what you do and do what you say” system, and it provides formalized recording of your processes and a structured way to change and maintain them.  Once your written processes are in place, you know what you have, and what you have not.  But just as a house foundation does not provide shelter from the environment without walls and a roof, the QMS alone is not enough for a compliant IEC 61508 process.

In the overall development process, each phase is divided into elementary activities with the scope, inputs, and outputs specified for each phase.  A V-Model approach considers these distinct phases:

• Concept
• Requirements
• Architecture design
• Detailed design
• Implementation
• Unit test
• Integration test
• Validation test

In addition, there are three non-phase-specific processes that need to be considered:

• Documentation Management
• Configuration Management
• Functional Safety Management 

 These three areas provide support and structure across all of the development phases.