welding /Bolting

Welding Special Inspection

A Special Inspector for structural welding is a highly qualified professional, often a Certified Welding Inspector (CWI), responsible for verifying that all welding for the building's structural frame and lateral force-resisting elements meets the standards defined in the approved plans, specifications, and the American Welding Society (AWS) codes.

The key distinction in welding inspection is the required frequency, which is classified as either Continuous or Periodic.

Welding Inspection Duties

A Structural Welding Special Inspector’s duties are grouped into three phases:

1. Pre-Weld Inspection (Continuous/Periodic)

The inspector verifies that the job is ready for proper welding.

• Welder Qualifications: Verifying that the welder is currently qualified to perform the specific type of weld on the project, typically by checking their qualification records.

• Weld Procedure Specification (WPS): Confirming a written, approved WPS is available and that the welder is following the parameters (e.g., proper welding process, current, voltage, electrode type).

• Material Verification: Checking the grade, type, and size of the base steel and filler metal (welding rods) to ensure they match the specifications.

• Joint Preparation: Inspecting the alignment, fit-up, cleanliness, and required joint geometry (bevels, root openings, backing bars) before any welding begins.

2. Welding in Progress (Continuous)

Certain critical welds require the inspector to be continuously present while the welding is performed.

• Temperature Control: Monitoring the preheat and interpass temperatures to prevent cracking in certain steel types.

• Weld Passes: Observing the proper cleaning of slag and spatter between multi-pass welds.

• Equipment: Verifying that the welding equipment is calibrated and that the settings (e.g., voltage and amperage) are within the qualified WPS range.

3. Post-Weld Inspection (Periodic)

After the weld has cooled, the inspector verifies the final quality.

• Visual Inspection: Performing a 100% visual inspection of the completed weld using calibrated gauges to check for:

  • Correct size, length, and profile.

  • Defects such as cracks, undercut, porosity, and inadequate fusion.

• Nondestructive Testing (NDT): Verifying that required NDT (such as Ultrasonic Testing (UT), Magnetic Particle Testing (MT), or Dye Penetrant Testing (PT)) is scheduled and performed by qualified Level II personnel to check for subsurface defects.

• Documentation: Marking accepted welds with a distinguishing stamp or paint, and documenting all accepted and rejected work in detailed daily and final reports.