Precommissioning checks

Ideally the field instrumentation and process connections — for example, impulse lines for dp cells — should have been properly installed prior to commissioning as should the infrastructure such as power and air supplies, con-duits/trunking/cable trays, wiring of termination cabinets and tags. In practice this is rarely so, and the primary objective of the pre-conunissioning process is to identify faulty installation. If quality assured procedures have been used by the installation contractor, credit may be taken for this and some of the precommissioning checks omitted. 

The last step in a properly run control project is to conduct a post audit. Collect postcommissioning data and compare them to precommissioning data. Make sure the new operating point is economically better than the old one. Check to ensure that the standard deviations of economically important CVs (often associated with product specifications) have decreased significantly. Evaluate whether the MV bounds are still set correctly. Can they be widened Is the controller forcing the process to run at the best set of constraints most of the time ... 

Check-sheets, or schedules, appropriate to the particular phase and activity should be available, commencing with those required during testing at the equipment vendor s factory, ihj-ough to construction and precommissioning. 

Any procedures relating to specific activities of precommissioning and commissioning must be available with the check-sheets. 

The emphasis in precommissioning is chi checking. An essentia] fir step in the precommissioning of insmimentanon is a visual inspection of the installation such as its mounting, associated pipework and wiring, and to check that the workmanship is of an acceptable standard. 

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