Automation System Hot Cutover Requires Careful Planning

It must be one of those weeks where a theme accidentally emerges. This week, it’s discovering things to write about courtesy of Twitter. The subject for today’s post comes from Aaron Crews, a principal control systems engineer with The Automation Group (TAG). TAG joined Emerson earlier this year.

Aaron’s tweet alerted me that he’s tackling a project with a hot cutover. For those unfamiliar with the term, it’s converting over to a modern process automation system while the process is still running. It takes careful, detailed planning.

Aaron shared the cutover planning process with me on this DCS modernization project. The tasks include cutover scheduling, logistics planning, sequence planning, safety planning and cutover documentation.

Cutover scheduling requires all prerequisites be complete, including the control system configuration and installation, operator training, etc. The scheduling must take the overall operating conditions and plant maintenance activities into account.

The cutover logistics planning choreographs the space requirements and movements of the old and new equipment since both are in operation as the cutover is performed. Power, communications and other connections must be part of this planning since operator stations and I/O cabinets may be temporarily located during the transition process.

The cutover sequence planning looks at the order the process units will be converted from the old system to the new. Generally, a back-to-front order is used unless process conditions dictate a change. A key consideration in this phase is the switchover of the operators’ graphics. During this cutover process they are operating on both the old and new operator consoles. The plan needs to make this as easy as possible to operate during this switchover period.

Cutover safety planning is critical. All of the established plant safety procedures must be followed. For U.S.-based hot cutover projects, a pre-startup safety review should be conducted in accordance with the Occupational Health and Safety Administration (OSHA)
Process Safety Management (PSM) requirements. All team members must have completed the established plant safety-training program and must have the proper safety equipment.

The cutover documentation includes the collection and organization of all the required drawings and cutover reports. A process tracking system is created to ensure that all documentation is checked and that the cutover proceeds per the scheduled plan and that any required changes are noted.

For this particular project as with all hot cutover projects Aaron and his team identify the cutover challenges, associated risks and possible solutions–the earlier the better. This process begins with the initial field survey. The earlier these challenges can be identified, the better the planning and required solutions can be engineered in advance. In the detailed engineering phase, the best engineering solutions are determined for these challenges give the associated risk, cost and schedule considerations.

Aaron shared a few of the challenges on his current project, which I’ll share in a future post. If you’ve planned or participated in a hot cutover, how does this compare with your process?

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