Management of Change (MoC)
What is Management of Change?
Management of change (MOC) is a formal process for reviewing and authorizing modifications to a facility before they are made. Each proposed change is assessed for the hazards it could introduce and the level of risk those hazards present, then approved by the appropriate authority. Once the work is complete, the change is recorded so the facility’s documentation stays accurate.
As a core element of risk and process safety management, MOC exists because even small modifications can introduce hazards or increase risk in ways that are not obvious at the time they are made. Routing every change through the same structured review keeps a facility operating within the boundaries of its approved design and creates a traceable record of how that design has evolved over time.
What Counts as a Change
MOC applies to any modification that could affect how a process operates or the level of risk it carries. Changes typically fall into the following categories:
- Equipment & Materials: New piping or a modified relief system.
- Process Conditions: Changes to operating limits or control setpoints.
- Procedures: Revisions to how operations and maintenance work is performed.
- Organization: Staffing reductions or new contractor roles in safety-critical positions.
Replacement in kind is the main exception. When a component is swapped for one with the same specifications, the approved design has not changed and MOC is not required.
Types of Changes
MOC procedures distinguish changes by how long they are intended to last.
Permanent Changes
Modifications intended to remain in place indefinitely. These follow the full review and approval process, including updates to every affected record.
Temporary Changes
Changes approved for a defined period, such as a bypass installed during an equipment repair. Each temporary change carries an expiry date, after which the facility is returned to its original state or the change goes through permanent MOC.
Emergency Changes
Changes made urgently to address an immediate risk of harm or significant loss. These follow an expedited approval path, with the full review completed as soon as practical afterward.
The MOC Workflow
Most MOC processes move each change through the following steps:
- Initiation: The change is described, along with its technical basis and the equipment or procedures it affects.
- Hazard & Risk Review: A multidisciplinary team identifies the hazards the change could introduce and assesses the likelihood and severity of each, using methods suited to the change’s complexity.
- Approval: Authorized personnel sign off based on the review findings.
- ImplementationWhat is an Implementation? Implementation is the process of ... More: The change is made, and a pre-startup safety review confirms the work matches the approved design.
- Closeout: Affected drawings and procedures are updated, and personnel are trained on the change before the MOC is closed.
MOC vs. Change Management
The two terms sound similar but address different risks. MOC controls technical and organizational modifications to manage operational risk and protect process safety. Change management, sometimes called change enablementWhat is Change Enablement? Change enablement is a ReVisionz-... More, focuses on the people side of change by helping teams adopt new systems and ways of working.
Large initiatives can involve both. For example, replacing a control system requires MOC to manage the technical risk, along with change enablement to prepare operators for the new interface.