Safety networks, also known as industrial safety networks or safety instrumented systems (SIS), are dedicated communication and control systems designed to ensure the safety and protection of personnel, equipment, and the environment in industrial settings. These networks play a critical role in preventing accidents and mitigating risks in environments where hazardous processes and machinery are present.

Here are key aspects of safety networks:

  1. Safety Instrumented Systems (SIS): Safety networks are often integrated with safety instrumented systems. An SIS is a system designed to monitor critical processes and take appropriate actions to bring them to a safe state in the event of dangerous conditions or failures. SIS components may include sensors, logic solvers, and final control elements.
  2. Functional Safety Standards: Safety networks and SIS are governed by functional safety standards, such as IEC 61508 (for general applications) and IEC 61511 (for the process industry). These standards provide guidelines for the design, implementation, and management of safety systems.
  3. Fail-Safe Design: Safety networks are designed with a “fail-safe” philosophy, meaning they are engineered to fail in a safe state. This ensures that if any part of the safety system experiences a failure, it does not compromise safety but instead activates protective measures.
  4. Safety Protocols: Safety networks use specialized safety communication protocols that prioritize the transmission of safety-critical data. Common safety protocols include PROFIsafe, Safety over EtherCAT, and SafetyBUS p.
  5. Redundancy: Redundancy is a critical feature of safety networks. Redundant components, such as sensors, controllers, and communication paths, are used to ensure that safety-critical functions can continue to operate even in the presence of hardware failures.
  6. Diagnostics and Self-Testing: Safety devices in the network often include self-diagnostic capabilities. These devices regularly test their own functionality and report any issues to the control system. This allows for proactive maintenance and fault detection.
  7. Emergency Shutdown: Safety networks are used to implement emergency shutdown (ESD) systems, which can rapidly and automatically shut down processes in case of imminent danger. ESD systems are crucial in industries like oil and gas, petrochemicals, and nuclear power.
  8. Safety Interlock Systems: Safety interlock systems use safety networks to control the sequencing of events and ensure that specific conditions are met before allowing a process to proceed. This helps prevent unsafe conditions from occurring.
  9. Safety Instrumented Functions (SIFs): SIFs are specific safety functions within an SIS that are designed to prevent or mitigate specific hazards. These functions are often allocated a target Safety Integrity Level (SIL) based on the risk they address.
  10. Human-Machine Interface (HMI): Safety networks typically include an HMI that provides operators with information about the status of safety systems and allows them to take action in emergency situations.
  11. Testing and Verification: Regular testing and verification of safety networks and SIS are essential to ensure their continued reliability and compliance with safety standards. This includes periodic functional testing and proof testing.
  12. Documentation and Compliance: Comprehensive documentation of safety network design and implementation is necessary to demonstrate compliance with safety standards and regulatory requirements.

Safety networks are a critical component of industrial safety management, and their proper design and operation are essential to protecting personnel, assets, and the environment in industrial environments where safety risks are present. Compliance with safety standards and ongoing maintenance and testing are vital to ensure the effectiveness of safety networks.