Standard Guides:Welding Piping ASME API Asset Matrix

VisualSurface & Visual • CWI / CWI-VT

Certified Welding Inspection & Quality Oversight (CWI / CWI-VT)

Method Overview

AWS CWI / CSWIP Certified Welding Inspection supervising weld fit-up, root pass integrity, filler metal certification, WPS/PQR procedure validation, and post-weld NDT quality auditing across structural steel, pressure vessels, and process piping.

Core Method Specifications

Technique IDCWI

AcronymCWI / CWI-VT

CategoryVisual

ModalitySurface & Visual

Default Report TemplateCWI-Standard-Template

Target Applications & Governing Standards

3 Scopes Configured

Piping & Loops

ASME B31.3 ASME B31.1 API 1104 ASME Sec IX

Target Assets / Components:

Process Piping Weld SeamsCross-Country Pipeline JointsSmall-Bore Branch Connections

Detectable Defects & Anomalies:

• Lack of Root Penetration• Weld Porosity• Internal/External Undercut• HAZ Hardness Anomalies

Pressure Vessels

ASME Sec VIII Div 1 & 2 API 510 AWS D1.1

Target Assets / Components:

Reactor Vessel Girth WeldsHeavy Wall Head-to-Shell WeldsNozzle Reinforcing Pads

Detectable Defects & Anomalies:

• Lack of Fusion• Slag Inclusions• Toe Cracking• Incomplete Fill

Storage Tanks

API 653 API 650 AWS D1.1

Target Assets / Components:

Aboveground Tank Shell Vertical WeldsAnnular Bottom Plate Lap JointsRoof Support Structure

Detectable Defects & Anomalies:

• Shell Distortion• Weld Profile Undercut• Plate Edge Lamellar Tearing

Method Limitations & Operational Boundary Conditions

Critical physics limits, thermal envelopes, blind spots, and ASME Sec V / API procedural boundaries for CWI / CWI-VT.

Level III Procedure Control

Operating Temp Envelope

Standard Envelope-10°C to +50°C (14°F to 122°F) for personnel safety

High-Temp CapabilityInterpass temperature checking up to 350°C (662°F) using calibrated digital contact pyrometers or Tempilstik markers

Preheat and interpass temperatures must not drop below minimum WPS thresholds to prevent hydrogen cracking in HAZ.

Thickness & Dead Zone

Min ThicknessAny structural plate or pipe thickness qualified under ASME IX, AWS D1.1, or API 1104

Max RangeHeavy section structural columns up to 150 mm (6.0 in)

Near-Surface Dead Zone

Supervisory inspection encompasses fit-up, root pass, interpass, and final cap profile

Surface Condition & Couplant

Roughness & PrepWeld joint bevel preparations must be free of mill scale, rust, moisture, oil, and gouges per AWS D1.1 §5.15

Coating ToleranceWelding over shop primers permitted only if qualified by procedure welding test coupon

Geometry & Orientation

Orientation Sensitivity

Mechanical fillet weld gauges and bridge cam gauges require flat contact against parent plate and weld toe

Clearance:Direct visual access to root face prior to tacking and root pass deposition

Critical Blind Spots

•Sub-surface lack of side-wall fusion and interpass cold lap hidden inside multi-pass weld layers
•Delayed cold cracking (hydrogen-induced cracking) developing 24 to 48 hours post-welding under compressive stress
•Internal porosity or slag inclusions buried below the cosmetic weld cap

False Indication Trap:

Uneven weld ripple spacing misdiagnosed as excessive convexity or underfill

Recommended Cross-Validation

PAUTView Method

Volumetric audit of completed joint for internal fusion and planar discontinuities

MTView Method

Final surface examination of weld cap and HAZ for delayed hydrogen cold cracking

Level III Code Compliance Directive:AWS QC1 / CSWIP mandates strict verification of welder qualification records (WPQ), electrode oven holding logs, and calibrated amperage/voltage meters.