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Non-destructive testing, NDT

Non-destructive testing is a useful tool to control the quality of a product without deforming or destroying it.

Non-destructive testing, or NDT as it is called, is a way to find out if the quality requirements in manufacturing, installation or repairs of a product in areas such as nuclear power and pressure vessels, where there are stringent safety requirements, is fulfilled. NDT is useful when checking for cracks and other damage to a product or equipment that has been in operation.

It is important to use the right NDT method to be able to find and detect any imperfections. The choice of method is depending on the material, design and/or type of defect.

A common method to detect damage inside the material is to use X-ray and/or ultrasonic. To detect more of a surface damage it is better to use penetrant and/or magnetic particle instead. Other NDT methods that is also used is the eddy current and visual inspection.

Examples of areas where accredited NDT testing laboratories is required by the regulators are testing of mechanical components in nuclear power plant and also testing of pressure vessels.

Swedac accredits the laboratories who perform non-destructive testing.

Accreditation of NDT testing in Sweden is done against the requirements of standard SS-EN ISO/IEC 17025.

Information to those wishing to become accredited for non-destructive testing

For those wishing to become accredited for Non-destructive testing there are overall demands from different authorities. These are announced in a regulation from Swedac, STAFS 2003:12. The regulation requires among other things:
• the laboratory is independent, that is, fulfils the requirements as inspection body type A according to SS-EN ISO/IEC 17020
• the laboratory has access to proper equipment and qualified personnel, including at least one in each test method shall be qualified for level III
• the laboratory must independently perform at least three of the four most common methods of pressure vessels, one of which method should be x-ray
• the accreditation covers a number of test methods including acceptance rules
• non-destructive testing should be performed according to methods specifically qualified with regard to the testing of components in nuclear power plants that have been in operation

Requirements and guidance documents:

Legislation or other regulations which require accreditation in Sweden

AFS 2017:3, Användning och kontroll av trycksatta anordningar, föreskrifter
SSMFS 2008:13, The Swedish Radiation Authority´s regulation concerning mechanical components at certain nuclear facilities

Documents that contain accreditation requirements

SS-EN ISO/IEC 17025:2005, General requirements for the competence of testing and calibration laboratories
STAFS 2003:12, Accredited laboratories active within the technological field of non-destructive testing
STAFS 2015:8, Regulations and general guidelines on accreditation
STAFS 2011:33, Regulations and general guidelines on accreditation of laboratories
SSMFS 2008:13, The Swedish Radiation Authority´s regulation concerning mechanical components at certain nuclear facilities
ILAC P9:06/2014, Policy for Participation in National and International Proficiency Testing Activities
EA-2/15M:2008, Requirements for the Accreditation of Flexible scopes

Documents providing guidance for compliance with accreditation requirements

SWEDAC DOC 01:14, Assessment of quality systems in an electronic environment
SWEDAC DOC 02:5, Guidance for Swedac’s assessors on the assessment of laboratories based on the requirements set out in SS-EN ISO/IEC 17025:2005
SWEDAC DOC 03:9, Flexible accreditation for laboratories
SWEDAC DOC 04:2, Requirements on accredited bodies in respect of calibration and traceability
SWEDAC DOC 05:6, Internal audits – guidance for laboratories and inspection bodies
SWEDAC DOC 06:9, Swedac´s policy for the participation of accredited laboratories and inspection bodies in proficiency testing schemes
SWEDAC DOC 10:5, Vägledning för informationssäkerhetsarbete
ILAC P9:06/2014, Policy for Participation in National and International Proficiency Testing Activities
ILAC P10:01/2013, Policy on Traceability of Measurement Results
ILAC P14:01/2013, Policy for Uncertainty in Calibration
ILAC G17:2002, Introducing the Concept of Uncertainty of Measurement in Testing in Association with the Application of the Standard ISO/IEC 17025
EA-4/02, Evaluation of the Uncertainty of Measurement in Calibration
EA-4/15 G:2015, Guidance Accreditation for Non-Destructive Testing
EA-4/18 INF:2010, Guidance on the level and frequency of proficiency testing participation
EA-2/15 M:2008, Requirements for the Accreditation of Flexible scopes

Documents that specify acceptance criteria or specify requirements for assessed objects/systems/persons in Sweden

AFS 2005:2, Tillverkning av vissa behållare, rörledningar och anläggningar
SSMFS 2008:13, The Swedish Radiation Authority´s regulation concerning mechanical components at certain nuclear facilities
SWEDAC DOC 12:7, Vägledning vid användning av vågar på provningslaboratorier och kontrollorgan
ILAC G8, Guidelines on the Reporting of Compliance with Specification (under revision)
ILAC G18:04/2010, Guideline for the Formulation of Scopes of Accreditation for Laboratories (under revision)
ILAC G24:2007, Guidelines for the determination of calibration intervals of measuring instruments (under revision)