Precision
- Ensures captured reality matches design intent before handover.
- Establishes tolerance thresholds that prevent unsafe or costly deviations.
- Provides auditable QC reports for governance and compliance.
- Links validated outputs directly into MOC (Management of Change) workflows for traceability.
- Supports decision-making by project managers, survey leads, and compliance officers.
What is Validation?
The process of verifying that as-built conditions accurately reflect design intent within agreed tolerances.
What is Deviation Tolerance?
The predefined acceptance threshold that determines whether a measured difference requires rework, approval, or documentation.
Introduction to As-Built Validation
As-built validation ensures that the constructed or modified asset accurately matches its design intent, within defined tolerance thresholds. For project and engineering managers, this is not just a survey check—it is a governance and QA/QC-driven process. Reliable validation protects against unsafe deviations, avoids costly rework, and provides a defensible record for audits and compliance reviews.
Learn more about our [As Built Preparation And Validation] .
As-Built Capture to Validation Workflow (Laser Scanning QC)
The workflow begins with laser scanning capture and ends with a verified QC report that feeds governance and MOC systems. Each step has its own controls and checkpoints to ensure accuracy and reliability.
Control Points & Registration QA
- Establish survey control points to anchor scans in a consistent coordinate system.
- Run registration QA to confirm scans align without drift, overlap errors, or misalignment.
- Document control-point accuracy in the QC report as a traceable reference for future audits.
Cloud-to-Mesh / Model Deviation Analysis
- Compare point cloud data against 3D design models (BIM or CAD).
- Use color-mapped deviation plots to highlight areas outside tolerance.
- Segment deviations by discipline (e.g., piping, structural steel) for focused accountability.
Validation Report Deliverables
- Deviation maps showing color-coded tolerances.
- Annotated mark-ups with clash points or mismatches.
- QC summary certificate stating pass/fail criteria for each discipline.
Explore related workflows in [Pipeline Integrity Assessment: Methodology & Workflow]
Deviation Tolerances & Acceptance Limits
Deviation tolerances define what is acceptable, what requires review, and what must be reworked. Enforcing criticality-based thresholds ensures that high-risk systems remain safe and compliant.
H3: Tolerance Examples by Asset Class
Below are sample thresholds used in as-built validation and laser scanning QC.
| Asset Class | Typical Tolerance Limit | Action if Exceeded |
| Structural Steel | ±10 mm | Document if minor; rework if load-bearing |
| Piping ≤DN100 | ±5 mm | Immediate review; potential re-route |
| Piping ≥DN400 | ±15 mm | Document; MOC approval required |
| Civil Foundations | ±20 mm | Review structural integrity before acceptance |
| Safety-Critical Supports | ±3 mm | Automatic rework; no waiver permitted |
Role of Criticality & Safety Class
- Safety-critical systems (supports, pressure boundaries) demand strict limits and zero waivers.
- Non-critical deviations (e.g., minor civil misalignments) may be documented with engineering approval.
- Applying clear acceptance criteria avoids subjective decisions and ensures consistency across projects.
- Integration with clash detection and scan-to-BIM verification strengthens reliability.
Discrepancy Reporting & Approval Trails
When deviations are detected, the reporting process must ensure transparency, accountability, and traceability. This is where strong governance frameworks protect projects from disputes and compliance failures.
Visual Mark-Ups & Clash Lists
- Screenshots and annotated overlays highlight misalignments in 3D models.
- Clash detection lists categorize issues by severity, discipline, and action required.
- Clear, visual reporting enables faster decision-making by project managers and survey leads.
Approval Workflow & QC Sign-Off
- Deviations follow a structured approval trail: discipline engineer → QA/QC → client.
- Critical deviations trigger formal NCRs (Non-Conformance Reports) and corrective actions.
- Every approval is logged in the QC system to create an auditable trail for compliance and insurance.
Integration with MOC & Compliance
As-built validation is not only about measurement accuracy—it directly supports the Management of Change (MOC) and Process Safety Management (PSM) frameworks.
Feeding into MOC Systems
- All validated deviations must be entered into the MOC register to ensure traceability.
- Approved deviations are linked to change control documentation and risk assessments.
- This ensures no undocumented modifications compromise safety cases or regulatory filings.
Document Control & Traceability
- Validation outputs are version-controlled within the document management system.
- Metadata links deviations to their respective project specs, drawings, and approvals.
- This ensures an unbroken chain of custody, proving that deviations were detected, assessed, and approved under governance.
Explore how traceability is enhanced with [FLOW Software].
Benefits for Project & Asset Owners
For decision-makers, the value of as-built validation extends beyond accuracy—it underpins governance, safety, and asset lifecycle management.
- Governance & Accountability – Every deviation is traceable with an approval trail.
- Reduced Rework & Delays – Issues are caught early, before construction impact.
- Audit Readiness – Validation reports support compliance with regulators and insurers.
- Safety & Reliability – Strict tolerances ensure that safety-critical systems are not compromised.
- Extended Asset Life – Documented as-builts support future modifications, tie-ins, and maintenance.
Well-executed validation assures stakeholders that the facility is built to design intent, safety class, and compliance obligations—not assumptions
How NWE Delivers Reliable As-Built Validation
NWE applies a structured QA/QC framework that aligns with international standards, ensuring as-built validation is more than a survey check—it is a governance process.
Independent QA/QC Framework
- Validation is performed under an independent QA/QC program, ensuring impartial results.
- Processes align with API, ISO, and client-specific standards for auditable consistency.
- Critical deviations are escalated through formal governance and compliance workflows.
Tools & Platforms
- Advanced survey and comparison methods, including laser scanning QC and point cloud verification.
- Use of [FLOW Software] for structured deviation reporting, traceability, and dashboard visualization.
- Integration with client document control systems for seamless governance.
Next Steps
- Request an As-Built Validation Audit – Check current governance.
- Book a Demo – See deviation reporting in action.
- Send RFP – Engage NWE for turnkey validation services.
As-Built Validation FAQs: Tolerances, QC & Compliance
Q1: What is as-built validation in engineering projects?
A process that verifies field conditions match the design intent within defined tolerances, ensuring governance and compliance.
Q2: How does laser scanning support as-built validation?
Laser scanning captures precise 3D point clouds that are compared against design models to detect deviations early.
Q3: What are typical deviation tolerance limits?
Tolerances vary by asset class—e.g., ±5 mm for small-bore piping, ±10 mm for structural steel, and stricter for safety-critical supports.
Q4: Why is deviation reporting important?
It creates an auditable record, with visual mark-ups and approval trails, ensuring deviations are documented and resolved under QC governance.
Q5: How does as-built validation connect to Management of Change (MOC)?
Validated deviations are fed into MOC systems, linking change approvals, risk assessments, and compliance documentation.
Q6: What benefits do asset owners gain from as-built validation?
Reduced rework, improved safety, audit readiness, governance assurance, and long-term asset lifecycle support.
Q7: How does NWE ensure reliable as-built validation?
Through independent QA/QC frameworks, structured tolerance checks, and advanced tools like [FLOW Software] .
