How to Control Technical Changes After a Tower Packing Purchase Order Is Awarded
A purchase order does not always freeze a tower packing project forever.
After award, the customer may discover:
- actual tower diameter differs from the drawing;
- material must change;
- additional spare packing is required;
- manway dimensions are smaller than expected;
- inspection requirements have changed.
These changes can be managed.
What creates risk is allowing changes to move directly from an email into production without controlled review.
1. First Ask Whether the Change Affects the Product
A post-award change may affect:
- geometry;
- material;
- quantity;
- fabrication;
- packaging;
- inspection;
- lead time;
- cost.
Classify the change before implementation.
2. Establish the Current Approved Baseline
Before evaluating the new request, identify:
- existing PO revision;
- approved drawing revision;
- approved datasheet;
- current manufacturing status.
A change can only be evaluated properly against a known baseline.
3. Determine Manufacturing Status
The same change has very different consequences depending on timing.
Before Raw Material Purchase
Usually easiest to implement.
After Raw Material Purchase
May create unused material or new procurement.
After Fabrication Starts
May require rework.
After Final Inspection
May require complete remanufacturing.
After Shipment
May become a site modification or replacement order.
Timing matters.
4. Perform Technical Impact Review
If tower ID changes, check:
- segment dimensions;
- packing quantity;
- support fit.
If material changes, check:
- corrosion suitability;
- material availability;
- weight;
- certificates.
If packing model changes, check:
- geometry;
- hydraulics;
- quantity;
- support compatibility.
5. Review Commercial Impact Separately
Technical approval does not automatically mean the change is free.
Potential commercial effects include:
- additional raw material;
- scrap;
- new tooling;
- extra inspection;
- revised packaging;
- freight changes.
These should be agreed before implementation where required.
6. Review Schedule Impact
A small technical change can create a large delivery impact.
For example:
Changing SS304 to SS316L may require new material procurement.
Changing structured-packing segmentation may require new drawings and fabrication.
Record the revised delivery basis.
7. Issue a Controlled Change Reference
Useful identifiers include:
- Technical Change Notice;
- Purchase Order Amendment;
- Engineering Change Request;
- Change Order.
The project terminology may vary.
The important requirement is traceability.
8. Update All Affected Documents
Once approved, update:
- PO;
- datasheet;
- drawings;
- BOM;
- inspection plan;
- package marking;
- production instruction.
Do not leave the change only inside the approval email.
9. Withdraw Superseded Instructions
The workshop must know that the old requirement is no longer valid.
For example:
Rev. B — supersededRev. C — current
Otherwise different production groups may use different instructions.
10. Record Partially Completed Material
If some components were already manufactured to the old requirement, identify:
- quantity;
- disposition;
- rework possibility;
- scrap status.
Do not mix old and new configurations unintentionally.
Engineering Takeaway
A post-award technical change should follow:
Request→ Baseline Review→ Technical Impact→ Commercial Impact→ Schedule Impact→ Approval→ Document Revision→ Manufacturing Release
Changes are normal.
Uncontrolled changes are not.