Standards for Non-Destructive Testing (NDT) of Welds

Non-destructive testing (NDT) is essential for ensuring weld quality without damaging the component. Common methods include visual inspection, ultrasonic testing, radiography, magnetic particle testing, dye penetrant, and eddy current testing, along with more advanced or job-specific techniques.

There are many standards that guide the use and acceptance of these methods. Below are key types commonly used in the UK:

BS – British Standard, issued by the British Standards Institution.
EN – European Norm, developed by the European Committee for Standardization (CEN).
ISO – International Standard, agreed upon by the International Organization for Standardization.

While not exhaustive, these standards are widely referenced in welding inspection and quality control.

NDT Standards for Welded Joints

Below is a categorized selection of key British, European, and International standards relevant to NDT methods for welded joints. These include general guidance, specific testing methods, and personnel certification standards.

General Standards & Defect Classification

PD CEN/TR 15135:2005 – Design and NDT of welds
BS EN ISO 17635:2016 – General NDT rules for metallic materials
BS EN ISO 6520:2007 – Classification of geometric imperfections in welds
BS EN ISO 5817:2023 – Imperfection quality levels in fusion-welded joints (steel, nickel, titanium)
BS EN ISO 10042:2018 – Imperfection quality levels for arc-welded aluminium joints
BS M 42:1972 – NDT methods for thin gauge welds

Visual Testing 👁️

BS EN 13018:2016 – General principles of visual testing
BS EN ISO 17637:2016 – Visual testing of welded joints

Fig. 1: Visual Testing (VT)

Magnetic Particle Testing 🧲

BS EN ISO 9934-1:2016 – General principles
BS EN ISO 17638:2016 – Magnetic particle testing of welds
BS EN ISO 23278:2015 – Acceptance levels for magnetic particle testing

Fig. 2: Magnetic Particle Testing (MPI)

Radiographic Testing ☢️

BS EN ISO 5579:2013 – Film-based radiography (X- or Gamma rays)
BS EN ISO 17636-1:2022 – Film techniques for radiographic weld testing
BS EN ISO 17636-2:2022 – Digital radiographic techniques
BS EN ISO 10675-1:2021 – Acceptance levels (steel, nickel, titanium)
BS EN ISO 10675-2:2021 – Acceptance levels (aluminium and alloys)
BS EN ISO 13588:2019 – Automated phased array technology in RT

Fig. 3: Radiographic Testing (RT)

Ultrasonic Testing 🔊

BS EN ISO 16810:2024 – General principles of UT
BS EN ISO 17640:2018 – Techniques, testing levels, and assessment
BS EN ISO 16827:2014 – Sizing of discontinuities
BS EN ISO 23279:2017 – Characterization of weld discontinuities
BS EN ISO 11666:2018 – UT acceptance levels
BS EN ISO 22825:2017 – Testing austenitic steels and nickel-based alloys
BS EN ISO 10863:2020 – Time-of-flight diffraction (TOFD) technique
BS EN ISO 15626:2018 – TOFD acceptance levels

Fig. 4: Ultrasonic Testing (UT)

Penetrant Testing 💧

BS EN ISO 3452:2021 – General principles of penetrant testing
BS EN ISO 23277:2015 – Acceptance levels for penetrant testing

Fig. 5: Penetrant Testing (PT)

Eddy Current Testing ⚡

BS EN ISO 15549:2019 – General principles of eddy current testing
BS EN ISO 17643:2015 – Eddy current testing of welds (complex plane analysis)

Fig. 6: Eddy Current Testing (EDT)

Certification & Qualification of Personnel 👷

BS EN ISO 9712:2022 – Qualification and certification of NDT personnel
ISO/TS 11774:2011 – Performance-based qualification in NDT

Remarks

Following recognized NDT standards is crucial to ensure the quality and safety of welded structures. Whether it’s pressure vessels, pipelines, or structural steelwork, adherence to British, European, and international standards helps maintain uniformity, supports compliance, and reduces the risk of failure. For engineers, inspectors, and quality assurance professionals, staying updated with these standards is an essential part of best practice in welding and fabrication industries.

– VCI