Structural · 10 checks

Site Welding
QA inspection checklist

Site and workshop structural welding quality audit, WPS, welder approval and inspection.

Every check below carries what good looks like, when it passes, the standard it comes from and the defects that usually fail it. That guidance is what turns a tick-box into an inspection.

Pre-Weld & Procedure

  1. 1.
    Welding Procedure Specification (WPS) available and matches the joint being welded
    What to look forWPS on site covers the parent material, thickness, joint type, position and consumables actually being used. WPS supported by a Welding Procedure Qualification Record (WPQR/PQR).
    Acceptable whenWPS qualified to BS EN ISO 15614-1 (steel) for the joint type, material grade, thickness range and position being welded. WPS reference recorded against the weld on the weld map.
    StandardBS EN ISO 15614-1:2017, Welding procedure qualification. BS EN 1090-2:2018.
    Common defectsWPS for the wrong joint type or thickness range usedNo WPQR supporting the WPSWPS not available on site, welder working from memoryWPS revision not matched to the current drawing
  2. 2.
    Welder qualification to BS EN ISO 9606-1 current and covers the process, material and position
    What to look forWelder's qualification certificate lists the process (MMA/MIG/TIG etc.), material group, thickness range and position welded. Certificate in date, typically requiring renewal every two years with evidence of continued welding.
    Acceptable whenCertificate to BS EN ISO 9606-1 valid for the specific combination of process, parent material, filler, thickness and position being used on site. Expired or non-matching certificates rejected.
    StandardBS EN ISO 9606-1:2017, Qualification testing of welders. BS EN 1090-2:2018.
    Common defectsCertificate expiredWelder qualified for flat position only, welding overhead on siteCertificate for a different material groupNo evidence of continuity of welding to keep approval valid
  3. 3.
    Welding consumables stored and controlled per manufacturer requirements
    What to look forLow-hydrogen electrodes stored in a heated rod oven, issued in controlled quantities and re-baked if exposed beyond the manufacturer's limit. Wire and gas certificates traceable to the batch in use.
    Acceptable whenConsumables stored and handled per the manufacturer's data sheet and the WPS. Rod oven temperature logged. Consumable batch traceable and matched to the WPS requirement.
    StandardBS EN 1090-2:2018 cl.7.5, Welding consumables. Manufacturer data sheets.
    Common defectsElectrodes left out of the oven overnight and used unbakedWrong consumable grade for the parent materialNo traceability of consumable batch to the weldGas cylinder contents not matched to the WPS shielding gas
  4. 4.
    Joint fit-up, root gap and alignment checked before welding starts
    Record: Root gap (mm)
    What to look forRoot gap, included angle and alignment of the joint measured against the WPS tolerances. Surfaces clean, free of mill scale, rust, paint or moisture at the joint.
    Acceptable whenFit-up within the tolerance stated on the WPS. Misalignment within the limits of BS EN 1090-2 for the execution class. Joint faces prepared and clean immediately before welding.
    StandardBS EN 1090-2:2018 Table 11/12, Fit-up tolerances.
    Common defectsRoot gap outside WPS toleranceMisalignment (hi-lo) exceeding the execution class limitJoint not cleaned before welding, contamination trapped in the weldTack welds not to the same WPS as the final weld
  5. 5.
    Preheat applied and verified where the WPS requires it
    Record: Preheat temperature (°C)
    What to look forPreheat temperature checked with a contact pyrometer or temperature crayon across the full width of the weld zone, not just a single spot, before welding starts and maintained through multi-pass welds.
    Acceptable whenPreheat temperature and extent per the WPS, typically calculated from combined thickness and carbon equivalent to BS EN 1011-2. Temperature checked and recorded before starting and between passes on thick material.
    StandardBS EN 1011-2:2001, Arc welding of ferritic steels. WPS requirement.
    Common defectsPreheat not checked, only assumed from ambient heatPreheat allowed to drop between passes on a multi-pass weldTemperature only checked at one point, not across the zoneNo record of preheat readings kept

Inspection & Traceability

  1. 6.
    Visual inspection carried out on every weld
    What to look forWeld profile, size, undercut, porosity, spatter and surface cracking checked against the acceptance criteria. Inspection carried out by a competent person, ideally CSWIP or equivalent qualified.
    Acceptable whenVisual inspection per BS EN ISO 17637, 100% of welds unless the specification defines a sampling rate. Findings recorded on the weld inspection report referencing the weld map.
    StandardBS EN ISO 17637:2016, Visual testing of fusion-welded joints.
    Common defectsInspection not covering the full length of the weldInspector not suitably qualifiedNo record of the inspection against a specific weld numberUndercut or porosity missed on a quick visual pass
  2. 7.
    Weld quality assessed against the acceptance level in BS EN ISO 5817
    What to look forImperfections (undercut, porosity, spatter, profile) measured against the quality level (B, C or D) specified for the structure. Level typically B for critical structural connections.
    Acceptable whenWeld quality level per BS EN ISO 5817 matched to the level called up on the drawing or specification, commonly Level C or B for structural steelwork. Any weld outside the acceptance level rejected or repaired per an approved repair procedure.
    StandardBS EN ISO 5817:2014, Quality levels for imperfections in fusion-welded joints.
    Common defectsWrong quality level applied (C used where B specified)Repair carried out without an approved repair WPSRejected weld reused without re-inspectionImperfection measured incorrectly against the standard
  3. 8.
    Non-destructive testing (NDT) carried out at the specified rate and method
    What to look forNDT method (UT, MPI, dye penetrant, radiography) matches the specification for the joint type and criticality. Sampling rate or 100% testing applied as required, with reports referencing the weld number.
    Acceptable whenNDT carried out by a qualified technician, typically PCN Level 2 or equivalent, at the rate and method called up in the project specification, commonly linked to execution class under BS EN 1090-2.
    StandardBS EN 1090-2:2018 Table 24, Extent of testing. Relevant NDT method standard (e.g. BS EN ISO 17640 for UT).
    Common defectsNDT sampling rate lower than the specificationTechnician not holding current PCN qualification for the methodNDT report not cross-referenced to the weld mapDefect identified by NDT not tracked through to repair and re-test
  4. 9.
    Weld map maintained, every weld traceable to welder, WPS and inspection record
    What to look forWeld map or register lists every weld by number, cross-referenced to the welder's stamp/identifier, the WPS used, and the inspection/NDT result. Map kept current as work proceeds.
    Acceptable whenEvery structural weld traceable to the welder, consumable batch, WPS and inspection result via the weld map, per BS EN 1090-2 documentation requirements. Map available for the completion file.
    StandardBS EN 1090-2:2018 cl.12, Documentation. Project quality plan.
    Common defectsWeld map incomplete or not kept up to dateWeld number on site not matching the mapNo welder identifier recorded against a weldInspection result not linked back to the specific weld
  5. 10.
    Welding executed to the execution class specified for the structure
    What to look forExecution class (EXC1-EXC4) stated on the drawing or specification matched by the level of WPS qualification, inspection extent and welder approval applied on site.
    Acceptable whenExecution class per BS EN 1090-2 Annex A/B consistently applied across welder approval, WPS qualification, fit-up tolerance and inspection extent. Class recorded in the project documentation.
    StandardBS EN 1090-2:2018 Annex A/B, Execution classes.
    Common defectsExecution class not stated or ambiguous on siteInspection extent lower than the class requiresWelder approval not matched to the class requirementNo single document confirming the execution class applied

Questions people ask

What is a site welding QA inspection for?

To record that the work was checked against the specification before it was covered up or handed over: a pass or fail against each item, a measurement where one matters, and a photo where it failed. It is the evidence a client's quantity surveyor or clerk of works asks for, and the thing that settles the argument at final account.

What standards does this checklist check against?

Each item names its reference. On this checklist that includes BS EN ISO 15614-1:2017, BS EN ISO 9606-1:2017, BS EN 1090-2:2018 cl.7.5, BS EN 1090-2:2018 Table 11/12, BS EN 1011-2:2001, BS EN ISO 17637:2016. The contract specification and the approved drawings always take precedence over a general standard; where they say something stricter, inspect to that.

Who signs a QA inspection off?

The person who carried out the check, named and dated, and where the contract calls for it the client's representative as a witness. The signature records that the check was done and what was found. It is not a warranty of the work.

How many items are on it, and do I have to use them all?

10 checks across 2 sections. Delete what does not apply to the job and add anything the specification asks for that is not here. A checklist that has plainly been thought about carries more weight than a long one nobody read.

Is this useful for a subcontractor as well as a main contractor?

More so. The subcontractor is the one who gets asked to come back and open something up. A signed inspection sheet with photos at the time is the cheapest insurance on a construction site.

Run this inspection on a phone

The same 10 checks, with the guidance a tap away, photos against each fail, measurements recorded, an NCR raised automatically and a branded PDF at the end. Signed on site. 14 days free.

Start free trial