Insufficient safeguards are in place when a safety critical system is not working properly or is bypassed.
- Failure of or unreliable safety systems.
- Testing of interlocks.
- Turnaround or maintenance work.
- Commissioning, start-up & shutdown.
Challenges in the Field
- Consequences are unknown.
- Safety systems that prevent start-up.
- Lack of knowledge of procedure.
- Absence of authorizers.
Options to Get it Right
- Understand the safety critical systems and identify them in the field.
- Every bypass/override needs a formal authorization based on a risk assessment (a special permit to work for bypass can help).
- Define the criticality of the system to bypass like the SIL level.
- Authorisation level needs to be inline with criticality.
- Identify solid interim protection measures and put them in action.
- The bypasses must be registered in a bypass log accessible in the control room.
- Discuss active bypasses during shift handover.
- Determine process units that require shutdown when safety critical systems are unavailable.
- Limit bypass duration, initiate a formal MOC for long term bypasses.
- Protect safety interlocks against easy bypassing in the field.
- Review bypassed functions daily (typically in the morning meeting).
- Review statistics on bypassed equipment.
This page only summarises the guidance – refer to the EPSC website for further information.
For more information on our Process Safety Fundamentals (or other) playing cards please contact us.