Pre-commissioning covers the activities carried out during construction that prepare the unit to move into the main commissioning phase. Pre-commissioning activities include:

• Filter installation
• Installation of packing and internals in distillation columns
• Catalyst loading in reactors
• Verification of tests, inspections and non-destructive testing
• Verification of hydrostatic tests
• Cleaning of piping and equipment
• Factory and site acceptance tests
• Listing and follow-up of pending construction and instrumentation activities (punch list)
• Control loop checks

Typical documents and activities in the Pre-Commissioning phase

• Definition of operating systems
• Procedures for flushing, blowing, chemical cleaning, equipment inspection (electrical, mechanical and instrumentation), final equipment closure, cold alignment and static tests of electrical equipment and instrumentation, among others
• Lubricant verification and filling
• Seal verification and filling
• Protection settings
• Punch list control
• Operation and maintenance manuals
• Blind list, terminal points and bolt torquing procedure
• Commissioning and start-up sequence
• Planning

This phase begins once most of the mechanical completion of the plant or systems has been achieved. It includes verification of conformity with design, verification of mechanical, electrical and instrumentation installations, cleaning of equipment and piping, and preliminary adjustments to equipment and systems.