Safety Functions of Instrumentation

The safety functions of instrumentation, control, and alarm systems shall:

  1. Provide information on out-of-tolerance conditions/abnormal conditions

  2. Ensure the capability for manual or automatic actuation of safety systems and components

  3. Ensure safety systems have the means to achieve and maintain a fail-safe shutdown condition on demand under normal and abnormal conditions, actuate alarms to reduce public or site-personnel risk, and inform operators of safety actions required and completed (e.g., effluent monitoring components and system).

The design of safety-related instrumentation and control systems must incorporate sufficient independence, redundancy, diversity, and separation to ensure that all safetyrelated functions associated with such equipment can be performed under postulated accident conditions as identified in the safety analysis.

Safety-related instrumentation and alarm-system designs must ensure accessibility for inspection, maintenance, calibration, repair, or replacement.

Safety-related instrumentation, control, and alarm systems must provide the operators sufficient time, information, and control capabilities to perform the following safety functions:

  1. Readily determine the status of critical facility parameters to ensure compliance with the limits specified in the Technical Safety Requirements.

  2. Initiate and verify completion of manual safety functions or verify automatic action is initiated and completed.

  3. Determine the status of safety systems required to ensure proper prevention of the accident or mitigation of the consequences of postulated accident conditions and/or to safely shut down the facility.

Safety-related ventilation system designs must provide manual or automatic protective control features.

Alarm Management Guidance shall be considered requirements for safety related instrumentation systems.

Guidance: The preferred method to prevent or mitigate a safety basis event is to provide automatic protective features with appropriate alarms to indicate the approach to actuation of the automatic feature and monitoring devices to provide accurate indication of the sensed parameter value, etc

1 Like