Sample activities for heat exchanger cleaning and i nspection work
Activities and work steps are very useful information. If you know the scope, steps and activities, schedule, resources and cost plan can be developed easily and monitored. The followings are the activities for shell & tube heat exchanger (AES type)’s maintenance work required to perform cleaning work and inspection during shutdown.
1. Scaffold erection to access tube bundle pulling work & blinding & de -blinding work 2. Remove pipe insulation for blinding work 3. Line to be isolated, drain and purge the system ready to blinding 4. Blinding work before pipe spools are removed 5. Removal of channel head spools and shell side spools 6. Removal of channel cover, channel head, shell cover and floating he ad 7. Dis-assemble backing device 8. Pull tube bundle and send it to cleaning yard at site 9. Cleaning tube bundle by hydrojecting 10. Shell side internal cleaning at site 11. Shell side visual inspection 12. IRIS inspection on tubes 13. Repair tubes (if found damages) 14. Send tube bundle back to site 15. Reinstate tube bundle 16. Install back channel head, channel cover,backing device 17. Perform tube side leak test 18. Install floating head, shell cover, conduct shell side leak test 19. Reinstate channel outlet pipe spool 20. Bolt Torqueing on shell & tube side flanges 21. De-blind as per blind list and sign off in flange check list 22. Conduct the overall tightness test (OATT) with operation 23. Reinstate piping insulation 24. Dismantle scaffold 25. Housekeeping work around job site area
The detail activity list list for shell & tube heat exchanger cleaning and inspection work to be performed during shutdown period should be ready before develop schedule. The followings should be considered when you work out the activities, activity duration, manpower, tools and equipments requirement;
Location of heat exchanger (To estimate scaffold Qty and lifting requirement) Pipe size Insulation type & thickness Shell & tube side flanges' size Tube bundle weight, length and tube size
Design pressure on tube side & shell side Inspection requirements
The following schedule is developed based on 24 hrs calendar (Calendar ID=2) during shutdown time.WBS is broken down as 1. Heat Exchanger Cleaning and Inspection 1.1 Pre-Shutdown Work 1.2 Shutdown Work 1.2.1 Piping 1.2.3 Mechanical 1.2.4 Inspection 1.3 Post-Shutdown Work
Sample shutdown schedule for heat exchanger cleaning and inspection work The detail activity list for shell & tube heat exchanger cleaning and inspection work to be performed during shutdown period should be ready before develop schedule. The followings should be considered when you work out the activities, activity duration, manpower, tools and equipments requirement;
Location of heat exchanger (To estimate scaffold Qty and lifting requirement) Pipe size Insulation type & thickness Shell & tube side flanges' size Tube bundle weight, length and tube size Design pressure on tube side & shell side Inspection requirements
The following schedule is developed based on 24 hrs calendar (Calendar ID=2) during shutdown time.WBS is broken down as 1. Heat Exchanger Cleaning and Inspection 1.1 Pre-Shutdown Work 1.2 Shutdown Work 1.2.1 Piping 1.2.3 Mechanical 1.2.4 Inspection 1.3 Post-Shutdown Work
WBS ( Work Breakdown Structure ) for Engineering and Construction Below figure is shown up to WBS (level-2) for an EPC project including shutdown scope for a petrochemical revamping project . The detail design engineering is broken down into disciplines engineering. Construction is broken down into pre-turn around and major construction.
1. The level 1 WBS elements are as follows; 2. Feasibility study 3. Basic design and engineering 4. Detail design and engineering 5. Procument 6. Construction
And Detail design and engineering is further broken down into level 2 WBS as follows; 1. Project engineering 2. Mechanical engineering 3. Process engineering 4. Piping engineering 5. Civil/Structure engineering 6. Electrical/Instrumentation engineering Level 1 WBS element , Construction can be decomposed into level 2 WBS as follows if revamp scope is included; 1. Pre Turn Around construction 2. Turn Around construction 3. Major construction
Construction would be decomposed into level 2, 3 WBS as follows if the project scope doesn't include revamp work. Level 2- Plant Area Name Level 3- Offsite Fabrication/Assembly Work Level 3-Onsite construction Work
Sample Work Activities for Process Tank Fabrication Fabrication work steps and activities are defined depends upon on the scope of tank components, type of materials and necessary inspection. Suppo se a process tank prefabrication scope includes the following components, (1) Tank body (2)External components attached to tank shell Man-ways on shell side and roof side Inlet and outlet pipe nozzles bottom drain pipe (3) Internal components Skimming box Stilling Wells & Level Gauge, Internal Spiders (4) Tank Access Steel Work Spiral Staircase Top Roof Platform (5) Accessories, Transport Saddles and Lifting Beam to facilitate lifting work
Assume that material for tank body, internal parts, man-ways and nozzles are stainless steel, and for staircase, tank roof platform and bottom drain pipe are carbon steel material. (1) Activity and work steps for tank body fabrication (a) Base Plate Marking and cutting Tacking and welding PMI Testing Removal of backing plate Vacuum box test welds Erect Scaffold for access (b) Shell Plate Fabrication (1st Course) Marking and cutting Rolling of plate Setting and tacking joint to base plate, vertical joint Full welding Holding down plates installation NDT Joints (DPI, RT) PMI Inspection (c) Shell Plate Fabrication (2nd Course) Marking and cutting Rolling of plate Scaffolding installation Setting and tacking joint to 1st course and vertical joint Full welding NDT Joints (DPI, RT) PMI Inspection (d) Shell Plate Fabrication (3rd Course) Marking and cutting Rolling of plate Scaffolding installation Setting and tacking joint to 2nd course and vertical joint Full welding NDT Joints (DPI, RT) PMI Inspection (e) Shell Plate Fabrication (4th Course) Marking and cutting Rolling of plate Scaffolding installation Setting and tacking joint to 3rd course and vertical joint Full welding NDT Joints (DPI, RT) PMI Inspection (f) Shell Plate Fabrication (5th Course) Marking and cutting Rolling of plate Scaffolding installation
Setting and tacking joint to 4th course and vertical joint Full welding NDT Joints (DPI, RT) PMI Inspection (h) Shell Plate Fabrication (6th Course) Marking and cutting Rolling of plate Scaffolding installation Setting and tacking joint to 5th course and vertical joint Full welding Rolling of curb angle Setting, tacking and full welding of curb angle Roof plate clip installation NDT Joints (DPI, RT) PMI Inspection Note. Nos. of course would be different depending on size of tank and how you define. (i) Roof Work Marking and cutting of roof ring plate, rafter, braces and roof clips Welding of roof ring plate, rafter and braces Marking and cutting of roof plate Fit up and welding of roof plate PMI test Vacuum box test welds Position and bolt up Roof to tank body Full welding of roof to curb angle PMI Test (2) Activity and work steps for external components fabrication
(a) Man-ways Marking and cutting of plate and reinforcement plate Rolling and welding of man-way plate Fabrication of flanges, hinges, handles and cover Assembly of cover, handles and hinges Fabricate reducing flange Marking and cutting of man-ways in tank shell Marking and cutting of man-ways in roof Fit up and welding of man-ways in tank shell Fit up and welding of man-ways in roof Installation of reinforcement pads in tank shell Installation of reinforcement pads in roof PMI test Pressure test reinforcement pad (b) Inlet and outlet pipe nozzles Marking and cutting of pipe and reinforcement plate Fabrication of nozzles NDT Joints (DPI)
Marking and cutting of nozzle location Fit up and welding nozzle PMI test Installation of reinforcement pad PMI test (c) Bottom Drain Pipe Marking and cut to length Tack and welding joints PMI Test NDE Testing (DPI, RT) Modify bottom drain and piping support NDE Testing (DPI, RT) Hydrotest of drain line Painting work (3) Activity and work steps for internal components fabrication
(a) Skimming Box Marking and cutting Assemble skimming box Rework Skimming Box Fit up and welding inside tank PMI test (b) Stilling Wells and Level Gauge Marking and cutting of pipe and frames Pipe drilling holes Fabricating of support frames Fabricate stilling wells and level gauge NDT Joints (DPI, RT) Fit up and welding of support frame Positioning of stilling wells and level gauge PMI test (c) Internal Spiders Marking and Cutting Roll end plate Fit up & welding of support clip PMI test Assemble internal spider NDE Testing Fit up to tank (4) Activity and work steps for Tank Access Steel Work Fabrication (a) Spiral Staircase Rolling of stringers Marking & Cutting of length material, support clips Fit up & welding of support clips PMI test Assembly of spiral staircase
Assembly of handrail NDE Testing Trail fit to tank shell Disassembling Galvanizing Packing Delivery
(b) Top Roof Platform Rolling of structure ( angle ) Marking & Cutting of length material, support clips Fit up & welding of support clips PMI test Assembly of top platform Assembly of handrail NDE Testing Trail fit to tank roof Disassembling Galvanizing Packing Delivery (5) Lifting Accessories (a) Transport Saddles Marking and Cutting Assembly of saddles Fit up & welding of saddles NDE Testing PMI test (b) Lifting Beam Marking and Cutting Assemble lifting beam NDE Testing Certification of lifting beam Painting of beam Note: NDE= Non Destructive Examination PMI= Positive Material Identification DPI= Dye Penetrant Inspection/Liquid Penetrant Inspection (LPI) Finally, most of the activities covered in this post would help you in developing a production schedule
