Pre-commissioning is a vital phase in the overall ethylene plant construction /start-up schedule. The respective assignments and responsibilities will be agreed and allocated between the licensor/engineering company, the construction contractor, the related equipment vendors and the client. Pre-planning of the entire pre-commissioning and commissioning phases is essential at an early stage in the basic design phase. Exact definitions of the respective mechanical completion, pre-commissioning, commissioning and start-up activities are essential at the outset of the project. Pre-commissioning typically begins up to 9 months prior to actual start-up. A key aspect is the designation of the respective ISBL/OSBL plant systems, their post-construction inspection and delivery, and the correct involvement of all parties. Corresponding budgetary costs must be estimated and approved.

An essential element of successful pre-commissioning is the precise definition of the activities involved and the approved documentation to validate related tests and results.

The specific activities involved include: • Air blowing • Steam blowing • Water flushing • Vessel cleaning • Chemical cleaning • Speciality cleaning, eg HP water blasting • Equipment inspection • System dryout • Critical instrumentation function testing

Conscientious completion of the above pre-commissioning activities sets the stage for successful pre and post start-up results.