A unit turnaround (TAR) provides opportunities for plants to execute capital and maintenance projects, or to make tie-ins during an outage window. This downtime is costly - not just in terms of lost production while the unit is down, but in the many hours of overtime paid to both plant employees and to contractors brought in specifically for the TAR. As a result, proper planning is critical to maximizing efficiency of the contractors and minimizing overtime. Questions and finger pointing do not get piping and equipment installed in a timely manner. The key to successful implementation of a project, large or small, during a short outage window is having thorough, detailed turnaround work packages. These packages provide the instructions for:
- Ordering materials
- Field preparation work
- Field installation
- Documentation for the plant technical information group
The success of a planned TAR will hinge on the quality and comprehensiveness of the information provided in the work packages. In order to develop a thorough package, the scope of the job must be understood by personnel developing the package. A field walk-through and a review with maintenance and operations personnel are essential to understanding how to execute the job. In addition, the work package must be conscious of the environmental, health, and safety aspects of the job. Any one of these items can cause significant delays in execution.
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Once the preliminary review of the scope has progressed, the necessary items of the work package can be completed. Whether the work packages are for a line replacement, jump-over, or vessel tie in, any work performed on process equipment should at a minimum contain 7 distinct documents:
- Scope of Work – A detailed work scope for each work package will provide a sequence of events from pre-TAR activities (lead/asbestos abatement, strip insulation, special PPE requirements, etc.) to fabrication instructions with Q/A hold points, to post-TAR activities.
- Red Lined P&ID’s – All relevant P&ID’s should be red lined to clearly show the modifications being performed on the process.
- Drawings/Iso’s with BOM including line list and tie-in list – All work packages shall include a set of IFC drawings and Bill of Materials.
- MOC – If the work to be performed is considered an alteration, then approved and signed off PSM compliant documentation (MOC) should be included in the work package.
- Weld Quality Control Form (WQCF) – Most turnaround work will require welding on pressure equipment. A WQCF shall accompany all work packages to ensure that the welding procedure is clear, along with the required Non Destructive Examination (NDE) procedure(s) to be used.
- Tie-In Tags – Tie-in tags shall be installed on the equipment or piping requiring alterations prior to the turnaround. These tie-in numbers will also be designated on all Iso’s and P&ID’s associated with the job.
- Checklist – A checklist should be filled out for each job to verify all documentation has been completed for the particular turnaround package. Checklists should be signed off on by the Designer(s) and Project Engineer, and provided to the TAR Planning Group for proper planning and execution. Checklists should include, but are not limited to, the following:
- P&ID Redlines
- Line List w/ Design Temperature and Pressure
- Proper Pipe Specification Identified
- Support Details Properly Identified
- Specialty Items Identified
- Bill of Material
- Paint / Insulation / Heat Trace Specification
- Instrumentation Elements Identified
- Control Valve Bolt Pattern and Actuator Clearance
- Valve Handwheel Orientation and Pinch Points
- Insulation Clearance
- Dead Legs and Pocketed Lines Reduced or Eliminated
- Orifice Plate Straight Runs of Pipe
- Minimize Field-Fit Welds
- Piping Isometrics match P&ID’s
- Piping Plan and Sections
- Tie-in list Properly Populated
- Type of Tie-ins Identified and Tagged in the Field
- Prep Sketches
- Post Weld heat Treatment
- Drawing Register Properly Revised
- Nipolets for Vents & Drains
- Orifice Root Valve Orientation and Rod Out
- Gussets for Vibrating Service
- Demo Drawings and/or pictures
Taking time in the TAR planning cycle to ensure thorough work packages are developed for each project to be executed during the outage is guaranteed to save you time in the long run, which will save you money and headaches during your next TAR.
Bill Davies, P.E. is the Principal Mechanical Engineer at Engineering & Inspection Services, LLC. To learn more about EIS, visit their Expo page on the Inspectioneering Website: