How to

Basic Pre-Commissioning Inspection

General Procedure:

Before starting the plant operation, the plant should be commissioned. Before beginning a fresh installation, the finished device configuration must be completely screened to guarantee that the device is in complete operation, this is pre-commissioning.

For each system, a set of installation / Pre-commissioning checklist banks shall be compiled covering all the items in the system.

There are different specific pre-commissioning procedures and instructions for inspections, tests, and/or calibration of each item.

Inspection & Testing:

  • All pre-commissioning documents (viz. Pre-commissioning / installation checklists, punch lists, etc) shall be maintained for each system separately.
  • Each item on the checklists for installation / pre-commissioning shall be inspected for building, closure of inspection and corresponding authorization.
  • Each item on the checklists for installation / pre-commissioning is completed or checked, signed and dated.
  • Pre-commissioning shall be regarded complete only after all equipment and devices have been verified and any necessary corrective action is finished on the classified punch list.

Check With P&ID:

The pre-commissioning team shall check the system/subsystem against the relevant P&IDs approved for construction, which include:

  • Check that control valves, flow orifices and check valves are installed in the right direction. Ensure that proper isolation valves are installed in right direction as per P&IDs.
  • Check the correct relief valves are installed in equipment/piping as per the P&IDs
  • Check that particular valves are fitted with the locking system for “locked open” and “locked shut” switches. The display screens are placed as shown in P&IDs in ‘ open ‘ or ‘ locked ‘ locations.
  • Check that all toilets are linked to the closed/open drain header from the equipment/vessels etc.
  • Check that all winds from the equipment/vessels etc. are linked to the flare scheme or transferred as per P&ID to a secure place.
  • Check all piping/fittings meet the specification as per P&ID.
  • Check that the right sort of equipment (hot /cold/personal safety) and tracing are mounted on warm or cold devices in accordance with P&ID.
  • Check that appropriate P&ID tie out valves are fitted at the correct system places.
  • Check all piping specification breaks are as shown in P&ID.
  • Specific distance/clearance checks are given for pipeline and tools as stated in P&ID.


Instrumentation Engineer

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