BS EN 50090-2-3:2005

Introduction
1 Scope
2 Normative references
3 Definitions
4 General requirements
  4.1 General
  4.2 Method of establishment for the requirements
      4.2.1 HBES application environment
      4.2.2 Sources of hazards
      4.2.3 Hazardous events
      4.2.4 Derivation of requirements
5 Requirements for functional safety
  5.1 General
  5.2 Power feeding
  5.3 Environment
  5.4 Life time
  5.5 Reasonably foreseeable misuse
  5.6 Software and communication
  5.7 Remote operations
      5.7.1 General recommendations
      5.7.2 Within a single building or in its immediate vicinity
      5.7.3 From outside the building
      5.7.4 Management
Annex A (informative) Example of a method for the determination
        of safety integrity levels
Annex B (informative) Hazards and development of necessary
        Functional Safety Requirements
Annex C (informative) Some examples of non safety related HBES
        applications
Bibliography

Presents the requirements for functional safety for HBES products and systems, a multi-application bus system where the functions are decentralised, distributed and linked through a common communication process.