A Practical Guide for New Coating Inspectors

Coating inspection is a systematic quality control process that begins before surface preparation and painting work and continues until final handover and mechanical completion. For new coating inspectors, understanding inspection stages, mandatory checks, and proper documentation is essential to ensure coating durability and long-term asset protection in industrial and oil & gas projects.

This practical guide explains the core duties of a coating inspector, based on a typical Inspection & Test Plan (ITP) commonly used in onshore and offshore projects.

1. Document Review (Pre-Inspection Stage)

Before any site activity starts, the coating inspector must review and verify all project-related documents.

1.1 Coating Procedure Review

The inspector shall:

• Verify that the coating procedure is approved
• Ensure compliance with:
  • Project specifications
  • Paint manufacturer’s technical and product data sheets
• Confirm correct procedure number and latest revision status

Why this is important:
All coating inspection activities must strictly follow the approved procedure. If no approved procedure exists, work must not start.

1.2 Personnel Qualification & Certification

Check qualification and certification records of:

• Blasters
• Paint applicators
• Coating supervisors

Ensure:

• Certifications are valid
• Personnel meet project and specification requirements

Inspector tip:
Unqualified personnel significantly increase the risk of coating failure, rework, and non-conformance reports (NCRs).

2. Material Receiving Inspection

After document approval, inspection moves to incoming materials.

2.1 Paint & Abrasive Inspection

Inspect and verify:

• Paint type, grade, and manufacturer
• Batch numbers and shelf life
• Container condition (no damage or leakage)
• Abrasive size, cleanliness, and dryness

Only approved materials are allowed for surface preparation and coating application.

2.2 Storage & Handling Inspection

Verify that:

• Paint is stored in shaded and well-ventilated areas
• Storage temperature complies with data sheet requirements
• Abrasives are kept dry and free from contamination

Common mistake:
Paint containers placed directly on the ground or exposed to direct sunlight.

2.3 Equipment Inspection

Inspect and approve:

• Air compressors
• Blasting machines
• Hoses and nozzles
• Surface profile gauges
• Dry Film Thickness (DFT) gauges

Ensure all equipment is in good condition and calibration certificates are valid before use.

3. Application Stage Inspection (Critical Phase)

This phase contains the highest number of hold points and witness points and requires continuous monitoring by the coating inspector.

3.1 Surface Preparation Inspection

Before coating application:

• Verify surface cleanliness and preparation standard
• Check:
  • Surface profile
  • Dust level
  • Oil and grease contamination
  • Soluble salt contamination

Important:
Coating application must not proceed without formal surface preparation approval.

3.2 In-Process Primer / First Coat Inspection

During coating application, monitor:

• Paint mixing ratio
• Pot life and induction time
• Ambient conditions (temperature, relative humidity, dew point)
• Wet Film Thickness (WFT)

The inspector should be present throughout the application process.

3.3 Primer Coat Inspection Before Next Coat

After primer application:

• Measure Dry Film Thickness (DFT)
• Inspect for coating defects
• Verify curing condition and recoat interval

Approval is required before applying the next coat.

3.4 Intermediate and/or Top Coat Inspection

During application:

• Observe spray technique and overlap
• Ensure uniform coating and full coverage
• Monitor DFT within specified limits

3.5 Final Top Coat Inspection (Dry / Fully Cured)

After complete curing:

• Perform final DFT measurements
• Conduct visual inspection for:
  • Runs
  • Sags
  • Pinholes
  • Holidays
  • Missed areas

Industry standards referenced in this guide align with ISO 12944 coating protection standards
👉 https://www.iso.org/standard/64834.html

3.6 Repair and Touch-Up Inspection

For damaged or defective areas:

• Confirm proper surface preparation
• Verify the correct coating system
• Measure DFT after repair

Repaired areas must meet the same quality requirements as the original coating.

3.7 Safety Color Coding & Stenciling

Inspect:

• Correct safety colors as per project specifications
• Proper identification markings on pipelines and equipment

4. Pre-Commissioning Inspection

Final checks before system handover.

4.1 Final Coating Inspection & Punch Listing

Verify:

• Overall coating condition
• Identification of:
  • Damages
  • Missed areas
  • Incomplete work

All punch items must be recorded, rectified, and closed.

4.2 Mechanical Completion Punch Listing

Confirm:

• Closure of all coating-related punch points
• Completion of inspection reports and records

Final sign-off confirms completion of coating inspection activities.