What is the difference between a permanent change and a temporary change in the context of MOC?

• A. Permanent changes require no risk assessment.
• B. Temporary changes require full formal risk assessment.
• C. Permanent changes require formal risk assessment and approval for long-term changes; temporary changes may have shorter approval but still require risk control.
• D. There is no difference.

Answer: (C)

In MOC, changes to process safety are treated differently based on how long they will last. Permanent changes become part of the normal operation, so they must undergo a formal risk assessment and receive formal approval before they are put into service. This ensures the long-term modification is safe, and all related safety controls and documentation are updated accordingly. Temporary changes are deviations with a defined end date, so they can use a shorter, time-limited approval pathway and interim risk controls, but they still require assessing risk and planning how to manage and eventually revert the change. Both paths demand proper documentation and verification of safety, but the level and duration of formal approval differ. That’s why the correct approach is that permanent changes require formal risk assessment and approval, while temporary changes may have a shorter approval process but still require risk control.