ISO 9712 NDT Inspection

Welding Quality Control

Industrial Manufacturing

How ISO 9712-Certified NDT Personnel Support EN 15085, EN 1090 and PED Compliance

By First Welding Certification Technical Editorial Team

6 Min Read Time

31 Oct 2026

Table of Content

ISO 9712 – NDT Personnel Certification

UT, RT, MT, PT and other applicable non-destructive testing methods.

Verify personnel competence, certification level and method-specific scope.

Support inspection of railway, structural steel and pressure equipment welds.

Maintain examination results, inspection reports and traceability records.

Introduction

When manufacturing within industry, visual inspection may not be enough to confirm weld quality. Often internal defects, lack of fusion, cracking and many other imperfections will exist within the weld. Appropriate NDT techniques must be carried out by personnel with an understanding of how to correctly carry them out. NDT plays an important role within the manufacturing process for railway components, structural steels and pressure equipment. Within some standards such as EN 15085, EN 1090 and the Pressure Equipment Directive (PED) there are requirements for inspection/testing of welded components. ISO 9712 is an internationally recognised standard that sets the requirements for the qualification and certification of NDT personnel within industry. This helps to show that individuals have been assessed for competency in specific testing methods and industries.

By understanding how ISO 9712 relates to product standards and manufacturing requirements, companies will be able to plan appropriate inspection methods and keep accurate records.

Understanding ISO 9712 and its role in manufacturing

ISO 9712:2021 – Non-destructive testing — Qualification and certification of NDT personnel.

This standard sets down requirements for qualifying and certifying NDT personnel in industry. It outlines requirements for various testing methods. The main aim of this standard is to provide confidence that personnel carrying out, managing or assessing NDT have the correct level of qualification to do so. The standard deals with certain testing methods. ISO 9712 certification will be for certain methods. Just because someone is certified with one method does not mean they would be considered qualified for all methods.

For example, just because someone has a certificate in Ultrasonic Testing (UT) does not mean they are also certified for Radiographic Testing (RT).

What does ISO 9712 certification show?

ISO 9712 certification shows that the individual has been assessed for competency in the testing method and scope. This does not necessarily mean they have the authority to carry out all inspections. The employer must also take into account specific requirements for the role, procedures, equipment, product and written authority if required.

Common NDT Methods Used

Manufacturers will choose the correct testing method based on the material being tested, joint design, anticipated defects, inspection requirements and acceptance criteria.

Common testing methods are:

NDT Method	Abbreviation	Typical application
Ultrasonic Testing	UT	Detecting internal discontinuities in suitable materials and weld configurations
Radiographic Testing	RT	Examining internal weld conditions through radiographic images
Magnetic Particle Testing	MT	Detecting surface and near-surface discontinuities in ferromagnetic materials
Penetrant Testing	PT	Identifying surface-breaking discontinuities in suitable non-porous materials
Eddy Current Testing	ET	Examining electrically conductive materials for relevant discontinuities
Visual Testing	VT	Examining visible surface conditions and weld appearance within the applicable competence and method requirements

Why is this important?

Different testing methods will have different capabilities.

Ultrasonic Testing – Can be useful for detecting internal weld conditions based on the joint design and material.
Radiographic Testing – Can provide a permanent record of certain internal defects.
Magnetic Particle Testing – Suitable for detecting relevant surface and subsurface defects in ferromagnetic materials.
Penetrant Testing – Can detect surface breaking defects in suitable non porous materials.
Visual Testing – Helps to detect visible irregularities in the weld.

The manufacturer should choose the correct method based on the inspection requirements.

How ISO 9712 supports EN 15085 in railway manufacturing

When manufacturing railway components there will be welded components used in the rolling stock. This could be locomotives, passenger coaches, freight wagons and other railway items. EN 15085 sets out the requirements for welding railway vehicles/components. It is important to plan inspection requirements to help control weld quality. EN 15085-5 sets out inspection and testing requirements. These relate to the inspection class and competency of NDT personnel.

NDT Personnel

Within the railway component manufacturing process NDT personnel may be required to:

Carry out the chosen NDT method to inspect welded joints.
Detect relevant defects in the welded area.
Assess the results against the relevant acceptance criteria.
Create inspection reports.
Keep accurate records of the inspection results relating to the relevant components and welds.
Those carrying out NDT must have the correct level of qualification from EN ISO 9712.

Example

A manufacturer is manufacturing welded bogie frames for use in the railway industry.

Process:

Review approved drawings and welding requirements
Create welding procedures and assign qualified welders
Manufacture the welded frame
Carry out visual inspection and required NDT
Assess the results against the requirements
Record inspection results and resolve any non-conformances.

ISO 9712 certified NDT personnel will assist with the inspection. They will carry out the inspection within their scope of certification. The manufacturer must ensure that the inspection is carried out with the correct method and to the required level as per EN 15085.

EN 1090 structural steel inspection

EN 1090 will be relevant to manufacturers that are carrying out structural steel and aluminium components. Structural steel fabricators will manufacture beams, columns, joints, welded assemblies and other load bearing components. Depending on the execution requirements, design and project documents, inspection may be required.

NDT may be required to inspect welded joints.

NDT support
Depending on the inspection requirements, qualified NDT personnel may carry out:
Ultrasonic Testing on the relevant weld joints.
Magnetic Particle Testing on suitable ferromagnetic components.
Penetrant Testing on suitable surfaces.
Radiographic Testing if required by the inspection.

The manufacturer should ensure that the correct inspection method is being carried out to the required level, with the correct acceptance criteria and personnel competency.

Example

A fabricator is manufacturing welded steel joints for an industrial building.

Certain joints have been identified within the project documentation to be inspected further. The company will plan the required NDT, assign personnel with the correct method competency and record the results.

If any unacceptable indications are found, the manufacturer will follow the relevant non-conformance and repair process. Any required re-inspections will be recorded. ISO 9712 will support with personnel competency. EN 1090 and relevant project requirements will dictate any execution requirements.

Relationship between ISO 9712 and PED

The Pressure Equipment Directive 2014/68/EU relates to pressure equipment within its scope. Manufacturers of pressure equipment may manufacture pressure vessels, piping, boilers and other equipment. These must meet the relevant safety requirements and conformity assessment. NDT and weld inspection can play an important role.

NDT is important for pressure equipment

Pressure equipment can be subject to high pressures and temperatures. Weld defects can affect the integrity of pressure retaining components. Depending on the equipment, category, conformity assessment route, harmonised standards and technical requirements, manufacturers may be required to carry out certain inspections.

This could include:

Radiographic Testing of selected weld joints
Ultrasonic Testing of selected weld areas
Magnetic Particle Testing or Penetrant Testing of relevant surfaces
Inspection of repaired welds
Recording results.

PED Personnel Competency

Consider the requirements for permanent joints and NDT within the PED.

For certain categories of pressure equipment the directive states that personnel performing permanent joints and NDT must have the correct approvals/qualifications. Ensure that the correct route and requirements are being followed for the equipment category and relevant harmonised standards.

ISO 9712 can provide a recognised qualification and certification process for NDT. However, It is important to note that ISO 9712 certification does not give compliance with PED or replace any approvals, assessments or conformity assessments.

How NDT relates to ISO 3834 welding quality management

ISO 3834 sets out quality requirements for fusion welding of metallic materials. Where ISO 9712 focusses on NDT personnel qualification/certification, ISO 3834 looks at the controls during welding.

Area	ISO 3834	ISO 9712
Main focus	Quality requirements for fusion welding	Qualification and certification of NDT personnel
Main application	Welding process management	Non-destructive testing competence
Relevant activities	Welding planning, procedures, coordination and inspection	Performing and evaluating specified NDT methods
Manufacturing contribution	Controls welding quality	Supports reliable examination of components

For example, a manufacturer may put controls in place for welding as per ISO 3834. Qualified welders and approved procedures will be used. NDT personnel will be assigned with the correct level of qualification to inspect the required weld joints.

This will provide a more structured approach to controlling welding.

Choosing the right NDT personnel

Having a certificate for NDT does not necessarily mean you can carry out the inspection. Ensure that the individual has the correct certification for the task.

Consider the following:

Testing Method: Is the inspection requiring Ultrasonic Testing, Radiographic Testing, Magnetic Particle Testing, Penetrant Testing, Eddy Current Testing or other testing method?

Certification: Do the responsibilities require Level 1, Level 2 or Level 3 competency?

Industry/Product: Does the certificate cover the relevant industry and product?

Certificate Status: Ensure that the certificate is still valid and what the renewal/recertification requirements are.

Written Authority: Will the employer need to provide written authority? Will the individual need training for the specific role?

Procedure: Will the personnel know what the relevant inspection procedure, equipment, product requirements and acceptance criteria are?

Never assume that having a certificate means you are allowed to carry out any NDT.

Keeping accurate inspection records

Keeping records of inspection can help provide evidence. The manufacturer should keep records to show that the inspection was carried out on the correct component, weld, method and stage.

Useful records to keep include:

NDT Technician details and certification.
Relevant NDT method and procedure.
Component and weld reference.
Inspection date and location.
Equipment identification (if applicable).
Results and relevant indications.
Acceptance criteria and assessment.
Repairs and re-inspections (if applicable).
Final inspection status.

Suggested NDT inspection record:

Record field	Example information
Component	Pressure vessel shell
Weld reference	W-014
Examination method	Ultrasonic Testing
Personnel	Assigned certified NDT technician
Inspection procedure	Approved UT procedure
Result	Accepted / Rejected / Further evaluation
Report reference	NDT-UT-014
Follow-up	Repair and re-examination, if required

This will help to provide evidence that the inspection was planned, carried out and assessed as per requirements.

Common mistakes to avoid

Even if you have qualified NDT personnel, poor planning and recording can cause issues.

Common mistakes include:

Not checking the method coverage. Just because someone has one NDT certificate doesn’t mean they can do another method.
Not considering product requirements. Ensure that the testing method and level is correct for the product standard and project requirements.
Using an old/outdated certificate. Ensure that the certificate is valid and covers the correct scope.
Not putting in place written authority. Consider the employer’s responsibilities.
Incomplete reporting. Ensure that the results identify what component/weld was inspected.
Not recording repairs. Consider recording any repairs and re-inspections.
Confusing company certification with personnel certification. ISO 9712 is for NDT personnel and not full certification of the company’s quality management system.

Practical example of NDT inspection of a welded pressure component

A manufacturer is manufacturing a pressure vessel for use in industry.

Process:

Review the equipment design, PED requirements and relevant product standards. Identify what controls are needed for welding and inspection. Welding team will manufacture using the relevant qualified welding procedures and personnel.

NDT personnel will be assigned with the correct certification and competency to carry out the required inspection methods. Inspection team will inspect the welds. Results will be assessed against the acceptance criteria. Reports will be created.

If any unacceptable indications are found, the manufacturer will record the non-conformance. Corrective actions or repairs will be carried out. Any required re-inspections will be carried out. Inspection reports and relevant manufacturing records will be included within technical documentation.

This example shows how welding controls, NDT competency and product conformity requirements come together.

Frequently Asked Questions

What is ISO 9712 used for?

This standard sets out requirements for qualifying and certifying NDT personnel within industry.

What testing methods does ISO 9712 cover?

ISO 9712:2021 covers ultrasonic testing, radiographic testing, magnetic testing, penetrant testing, eddy current testing, leak testing, thermographic testing, acoustic emission testing and strain gauge testing. This depends on the scope of the standard and certification scheme.

Is ISO 9712 relevant for EN 15085 certification?

Yes. EN 15085-5 includes requirements for NDT personnel competency. The correct method and level of certification must be used for the inspection.

Does EN 1090 require all welders and inspectors to have ISO 9712 certification?

No. This will depend on the execution requirements, inspection requirements and relevant standards. ISO 9712 should be used where required or specified.

Does ISO 9712 certification automatically meet PED requirements?

No. There are a number of requirements to meet for PED conformity including design, materials, manufacturing, permanent joints, inspection and assessment. Ensure that the correct personnel qualifications are being used for the equipment category and relevant requirements.

Conclusion

NDT plays an important role in confirming the quality of manufactured components. Especially when welded joints are used in railway, structural steels and pressure equipment. ISO 9712 provides a framework to show NDT personnel competency. Standards such as EN 15085, EN 1090 and PED will set product or regulatory requirements. These may determine what inspection is required. The key is to ensure the correct inspection method is being used with the correct technical requirements, competent personnel, approved procedures and accurate records.

By working together with welding quality management and NDT inspection, companies can improve their manufacturing controls and provide accurate evidence for relevant conformity assessments.

Need guidance on ISO 9712 or welding certification requirements?

First Welding Certification Pvt Ltd (PRVÁ ZVÁRAČSKÁ, a.s.) can help you understand relevant welding qualification, welder certification, NDT, and material documentation requirements associated with your compliance planning.

Contact PZVAR today to discuss your certification and conformity assessment requirements.

Once Certified – Accepted Globally.