AD 2000
AD 2000 – guidelines supplementing the European Pressure Equipment Directive 2014/68/UE which must be followed by manufacturers of pressure equipment or materials to be used on the German market. The AD 2000 Code sets out the rules and guidelines for the pressure vessel technology and the related safety requirements for equipment, installations and marking, manufacturing and testing, as well as the materials used in pressure equipment.
ASME (American Society of Mechanical Engineers) is a non-profit member organisation which was established in 1880 by a group of engineering specialists. ASME regulations are applied, accepted and recognised in more than 150 countries, which makes ASME certification significant on the international market.
Acceptance level
Acceptance level – the level of imperfection threshold values for which a specific welded joint is deemed acceptable. In the case of visual inspection, the quality level is the same as the acceptance level. In UT, RT, PT and MT, the acceptance levels are equivalent to specific quality levels.
Accreditation – a confirmation of competence issued by bodies which certify products, services, persons, or testing or hallmarking laboratory systems as inspection bodies – for activities within a specific scope.
Approved laboratory
Approved laboratory – conformity with the requirements set out in a quality assurance system as confirmed by an independent body (UDT).
Audit – a systematic, independent and documented process of obtaining proof from an audit and its objective assessment to specify the degree of compliance with the audit criteria. It is performed to confirm the effectiveness of a system and identify the processes and tasks which require improvement.
Berthold indicator
Berthold indicator – a control apparatus for determining the sensitivity of indications in magnetic particle inspection and the direction of a magnetic field. It is used to control the direction and magnitude of magnetisation. It evaluates artificial cracks laid out in a cross-shaped manner.
CEN – Comité Européen de Normalisation – European Committee for Standardisation.
Calibration – an operation which involves determining the values indicated by the device being calibrated in relation to the corresponding values of the relevant measurement standard.
Calibration – all activities aimed at determining the relationship between the values of the measured quantity indicated by a measurement device and the corresponding values of physical quantities present in the measurement standard, as well as specifying the uncertainty of that measurement. In the simplest case this involves finding the difference between the indication of the reference device (higher-order measurement standard, higher-order reference material, higher-order measuring instrument) and the calibrated device (lower-order measurement standard, lower-order reference material, lower-order measuring instrument), taking into account the uncertainty of the measurement made using the reference device.
Calliper – an instrument for measuring the external and internal dimensions of object and their depth with the resolution of one hundredth of millimetre. Standard callipers allow measurements of up to 150 mm.
Cast – an object made by filling a mould (casting) with a liquid metal or alloy, which then hardens into the form, or other hardening material (such as gypsum, ceramics, basalt, glass, synthetic resin).
Certificate of competence
Certificate of competence – a document confirming the qualifications, knowledge and authorisations of an employee to perform specific types of non-destructive testing.
Certification audit
Certification audit – implemented by an independent entity for the purpose of granting a certificate.
Closed radioactive source
Closed radioactive source – a radioactive source designed in a way that, under its stated use conditions, prevents the radioactive substance contained within it from release to the environment.
Collimator – a shielding device restricting radiation to a defined constant angle. Beam limiting devices are usually made of lead, tungsten or depleted uranium and placed in the working position of the source.
Corrosion – the gradual destruction of metals and their alloys in the solid state caused by the chemical or electrochemical impact of the environment.
Crack – an instance where the maximum allowable stress (deformation) is exceeded, which results in exceeding a material’s tensile strength, i.e. loss of ductility.
Crater pipe
Crater pipe – a shrinkage cavity at the end of a weld run which has not been removed before or during the successive stages of producing the weld runs.
Crevice corrosion
Crevice corrosion – the gradual loss of a metal oxide layer in the crevices caused by restricted oxygen access. It occurs in crevices and structural openings below gaskets, deposits and scale, as well as in cracks.
Destructive testing (DT)
Destructive testing (DT) – testing methods which permanently alter the object being inspected. Destructive testing is performed on specially prepared samples or on finished products. Both are destroyed during the testing, which is why such tests are usually limited to a few (3-5) representative samples. This kind of testing is meant to characterise the behaviour of a material under load, or its operational strength.
Detection – finding, discovering, or noticing something. In exact sciences, such as chemistry and physics, the word “detection” refers to detecting electrical signals, radiation or motion of e.g. particles.
Developer – a substance with strong penetrant absorption properties. Developer is applied to the surface following excess penetrant removal to extract the remaining penetrant from all open discontinuities and reveal it on the surface. Its colour is in strong contrast to that of the penetrant.
Discontinuity – another term for imperfection.
Electrochemical corrosion
Electrochemical corrosion – occurs when two dissimilar materials remain in contact in an electrolytic medium. This corrosion usually takes place in the carbon steel–stainless steel combination.
Electromagnetic yoke
Electromagnetic yoke – a device used to generate a magnetic field when performing magnetic particle testing.
Excess weld metal
Excess weld metal – a protrusion from the welded joint thickness.
Exposure – the process in which the human body may be subject to ionising radiation.
External audit
External audit – an audit conducted by auditors who are independent of the organisation being tested.
Ferromagnetic materials
Ferromagnetic materials – ferromagnetics are materials with the strongest magnetic properties. An example of a ferromagnetic is iron.
Fluorescent suspension
Fluorescent suspension – a water-based suspension of fluorescent powder, ready to use, washable with solvent, appropriate for the testing of ferromagnetic metals.
Forging – the final product obtained in the process of plastic metal working. Depending on the type of plastic metal working technology, a forging might be closed-die (obtained in the impression die process) or open-die (made using the open-forging process).
Fusion– a type of joint produced in the physical process of combining materials by means of their local melting and solidification. Used e.g. to join metals (primarily steel) and plastics. Welding usually involves the addition of a welding filler, i.e. an additional material which melts along with the parent material and fills the joint.
GUM – Central Office of Measures. The Central Office of Measures exercises surveillance over the administration of measures and hallmarking in Poland. Its primary task is to ensure traceability, maintain the national measurement standards, ensure mutual conformity and specific accuracy of results of measurements conducted in Poland and their conformity with the International System of Units.
Gamma-ray source projector, gamma-ray flaw detector
Gamma-ray source projector, gamma-ray flaw detector – an apparatus with a gamma-ray source (selenium, iridium) composed of a device for exposure, an appropriate source module, remote control module, projector covers, exposure head and accessories allowing closed-source radiation emission.
Hardness – the property of solids defined as the resistance of a body under the influence of another, harder body with a specific force.
Hardness tester
Hardness tester – an instrument for measuring hardness. The design depends on the type of hardness measurement for which it is intended.
Hardness testing HT
Hardness testing HT with a portable hardness tester is a method of non-destructive testing using the UCI method. The UCI method uses a probe which features a rod with a Vickers diamond indenter mounted at the tip. The rod oscillates with a frequency of about 70 kHz as the probe’s diamond is pressed against the tested material and the frequency deviates from this base value according to the properties of the material being tested. The change in frequency is proportional to the contact area, or the indentation area created by the Vickers diamond. The device software compares the two frequencies and mathematically calculates the Vickers hardness (HV) value.
Heat affected zone (HAZ)
Heat affected zone (HAZ) the area around the weld in welded metallic materials. The microscopic structure and properties of this zone are different than those of the joined materials and the weld. The heat affected zone appears during welding, laser or plasma cutting.
Heat treatment
Heat treatment – a thermal process involving the appropriate heating, tempering and cooling to stated temperatures and with a specific speed, which causes changes in the properties of an alloy in the solid state. The purpose of heat treatment operations and procedures is to modify the mechanical and plastic properties of the material by changing its structure.
IBUS – a type of ultrasonic testing of butt welds using the echo technique involving shear wave tandem-array transducers, with a thickness range of 2.0 mm ÷ 8.0 mm and transducer diameter starting from DN25. IBUS is used to examine the whole volume of a weld to look for discontinuities such as: incomplete fusion, cracking, slagging and blistering strips, etc.
IEC – International Electrotechnical Commission.
ISO – International Organization for Standardization.
Imperfection – failure to comply with a requirement, i.e. to fulfil a specified, established or mandatory need or expectation.
Incomplete fusion
Incomplete fusion – lack of metallic connection (fusion) between the weld metal and the base material and between the individual layers or weld beads. Three types of incomplete fusion are distinguished: incomplete side fusion, incomplete interbead fusion and incomplete root fusion.
Incompletely filled groove
Incompletely filled groove – a characteristic concavity of the weld seam on the face side present along its whole width. Cause: excessive distance between the joined elements; excessive welding current; in the case of butt welding of stainless steel tubes, an incompletely filled groove occurs when the flow value of protective gas in the tube is too low.
Industrial sector
Industrial sector – the sector covering a specific type of elements and devices manufactured or used.
Insufficient fill on the root side
Insufficient fill on the root side – a characteristic concavity of the weld seam on the root side present along its whole width. It usually appears during the circular welding of tubes in the overhead welding position as a result of gravity acting on the thin liquid metal of the weld pool. Common causes of insufficient fill also include: incorrect layout of welding elements due to leaving excessive distance between them, excessive welding speed or too short free electrode end during welding under protective gas.
Intercrystalline corrosion
Intercrystalline corrosion – occurs when corrosion-resistant steel (e.g. austenitic) is heated up to 500°C÷800°C. It results in the formation of carbides at grain boundaries, which cause corrosion.
Interlaboratory comparisons
Interlaboratory comparisons – the organisation, performance and assessment of measurements or tests of the same or similar objects by at least two laboratories, in accordance with previously stated conditions.
Internal audit
Internal audit – an audit conducted independently from the department being audited, aimed at the operational improvement and introduction of added value to the organisation. Internal audits help organisations to achieve their goals through a systematic and methodical approach to the assessment and improvement of effectiveness of risk management, control and governance processes.
Intralaboratory comparisons
Intralaboratory comparisons – the organisation, performance and assessment of measurements and tests of the same object in the same laboratory, in accordance with previously stated conditions.
Ionising radiation
Ionising radiation – electromagnetic radiation (γ, X) or particle radiation (corpuscular, e.g. α, β), which has the capacity of directly or indirectly generating ions (excluding ultraviolet photons) when penetrating matter.
Ir-192 – iridium-192, one of the radioactive isotopes of iridium metal with atomic number 77, belonging to group 9, period 6 and the d-block of the periodic table. A source of Ir 192 is obtained by placing high-purity > 99.9% iridium in tablets with a thickness adjusted to the best geometry – in this form it is used for radiographic examination.
Laboratory – an entity which conducts one of the following activities: research, calibration, or collecting samples which are then subject to testing or calibration.
Laboratory approval certificate
Laboratory approval certificate – a document confirming that the approved laboratory complies with the requirements of technical conditions of the Office of Technical Inspection to perform non-destructive testing within the scope covered by the approval.
Lack of fusion
Lack of fusion – the difference between the actual and nominal depth of fusion.
Laminar imperfection
Laminar imperfection – a material defect involving the separation of layers from each other.
Leak – an excess amount of material at the weld root protruding from the plane of the welded material.
Leak testing using bubble emission techniques LT
Leak testing using bubble emission techniques LT is a non-destructive testing method which utilises the pressure difference between connected media and the penetration of gas from the medium with a higher pressure (atmosphere) to the medium with a lower pressure (vacuum chamber). The use of a foam solution in the vacuum chamber makes it possible to see the penetration of air from the atmosphere through the leaks, allowing to find their location.
Level of qualification
Level of qualification – the set of knowledge and competences required to conduct certain professional task groups. These result from specific documents (attestations, diplomas, certificates) and create the presumption that a given person has the appropriate competences.
Luxmeter – an instrument for measuring light intensity in lux. It is used for the visual comparison of brightness intensity (luminance) of the examined object with the brightness of a reference surface.
Magnetic field strength meter
Magnetic field strength meter – a device used for measuring the strength of a magnetic field.
Magnetic particle testing MT
Magnetic particle testing MT – a method of non-destructive surface and subsurface inspection (up to 2 mm of depth) used for ferromagnetic materials. It involves the introduction of a magnetic field into the object and observation of local dispersions of that field. Dispersions form directly above imperfections and are revealed with the use of fine particles applied to the surface of the inspected element during the application of the magnetic field.
Magnetic suspension
Magnetic suspension – a substance used in magnetic particle testing to locate surface and subsurface defects in elements made of ferromagnetic materials.
Manometer – a device for measuring pressure in relation to the ambient pressure, which is usually atmospheric pressure.
Measurement – a set of actions performed to determine the value of a specific physical or conventional quantity as the product of a measurement unit and the number specifying the numerical value of that quantity; in other words, a comparison of the value of a given quantity with the measurement unit of that quantity.
Measurement uncertainty
Measurement uncertainty – the parameter connected with the measurement result, expressing the dispersion of values that can be justifiably attributed to a measured quantity.
NDT manual
NDT manual – a guide for conducting tests which implements the general principles and guidelines contained in the testing procedure or directly in the product standard and provides a step by step description of the procedure of testing a specific object/product.
NDT procedure
NDT procedure – a guide specifying the course of action and responsibility when conducting non-destructive testing (NDT) from the moment of receiving the order to providing the results.
Non-destructive testing (NDT)
Non-destructive testing (NDT) – a group of testing methods providing information about the material properties of an object which do not significantly affect its structural and surface properties.
Ovality measurement
Ovality measurement – the measurement of two perpendicular diameters using the same measurement device. The more diameters are measured, the more accurate the measurement, provided that these diameters are rotated against each other by appropriate angles.
PCA – Polish Centre for Accreditation. A national accreditation body authorised to accredit conformity assessment entities pursuant to the Act of 13 April 2016 on conformity assessment systems and market surveillance.
PED (Pressure Equipment Directive) – full name: Directive 2014/68/EU of the European Parliament and of the Council of 15 May 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of pressure equipment.
PN – Polish Standard. Polish Standards are developed by Technical Committees, which are bodies consisting of experts delegated by standardisation institutions and approved by the Polish Committee for Standardization.
PN-EN – Polish Standard implementing an European Standard (by translation).
PN-EN 10160
PN-EN 10160 – “Ultrasonic testing of steel flat products of thickness equal or greater than 6 mm (reflection method).” This standard describes a method of ultrasonic testing of non-coated steel flat products, aimed at identifying internal discontinuities. It applies to flat products with a nominal thickness range from 6 mm to 200 mm, made of carbon or alloy steel.
PN-EN 10228-2
PN-EN 10228-2 – “Non-destructive testing of steel forgings – Part 2: Penetrant testing.” This European Standard sets out the acceptance techniques and criteria to be used in the penetrant testing of steel forgings for detecting surface discontinuities.
PN-EN 10228-3
PN-EN 10228-3 – “Non-destructive testing of steel forgings– Part 3: Ultrasonic testing of ferritic or martensitic steel forgings” This European Standard sets out the techniques that should be used for manual ultrasonic pulse-echo testing of ferritic or martensitic steel forgings.
PN-EN 10308
PN-EN 10308 – “Non-destructive testing – Ultrasonic testing of steel bars.” This standard describes a method of manual, pulse-echo, ultrasonic testing of steel bars with a diameter or equivalent thickness less or equal to 400 mm or equivalent section.
PN-EN 12680-1
PN-EN 12680-1 – „Founding – Ultrasonic testing – Part 1: Steel castings for general purposes.” This standard sets out the requirements for the ultrasonic testing of general-purpose steel castings (having a ferritic structure) and the methods for determining internal discontinuities using the pulse echo technique.
PN-EN 12681-1
PN-EN 12681-1 – “Founding – Radiographic testing – Part 1: Film techniques.” This standard sets out the requirements for film radiographic testing of castings and specifies the procedure for the choice of operating conditions in the process of casting steel, cast iron, aluminium, cobalt, nickel, titanium, zinc and their alloys.
PN-EN 1369
PN-EN 1369 – “Founding – Magnetic particle testing.” This standard sets out the requirements for the magnetic particle testing of ferro-magnetic iron and steel castings. It provides the acceptance criteria for severity levels defined by the nature, the area, and the dimensions of the discontinuities present.
PN-EN 1371-1
PN-EN 1371-1 – “Founding – Liquid penetrant testing – Part 1: Sand, gravity die and low pressure die castings.” This standard sets out the acceptance techniques and criteria (severity levels) for the penetrant testing of castings.
PN-EN 1593
PN-EN 1593 “Non-destructive testing. Leak testing. Bubble emission techniques.” This standard sets out the requirements for the detection and location of leaks by the following bubble emission techniques: immersion technique and liquid application technique.
PN-EN 1779
PN-EN 1779 “Non-destructive testing. Leak testing. Criteria for method and technique selection.” This standard sets out the criteria for the choice of method and technique for leak testing by indication or measurement of gas leakage.
PN-EN ISO – Polish Standard implementing an International Standard designated by CEN as a European Standard or jointly created by ISO and CEN.
PN-EN ISO 10228-1
PN-EN ISO 10228-1 – “Non-destructive testing of steel forgings– Part 1:Magnetic particle testing.” This standard sets out the acceptance techniques and criteria for the magnetic particle testing of castings made of ferromagnetic materials. The described method is used for detecting surface discontinuities.
PN-EN ISO 10675-1
PN-EN ISO 10675-1 – “Non-destructive testing of welds – Acceptance levels for radiographic testing – Part 1: Steel, nickel, titanium and their alloys.” This standard sets out the acceptance levels for indications from imperfections in butt welds of steel, nickel, titanium and their alloys detected by radiographic testing. If agreed, acceptance levels can be applied to other types of welded joints or materials. Acceptance levels may be connected with welding standards, product standards, technical conditions or regulations. When a welded joint fulfils the requirements specified for a given acceptance level, the imperfection sizes permitted by the standard are compared with the sizes of indications revealed by the radiographic testing of the welded joint.
PN-EN ISO 10893-10
PN-EN ISO 10893-10 – “Non-destructive testing of steel tubes – Part 10: Automated full peripheral ultrasonic testing of seamless and welded (except submerged arc-welded) steel tubes for the detection of longitudinal and/or transverse imperfections.” This standard sets out the requirements for automated full peripheral ultrasonic shear wave testing of seamless and welded, except submerged arc-welded (SAW), steel tubes, aimed at the detection of longitudinal and/or transverse imperfections.
PN-EN ISO 10893-4
PN-EN ISO 10893-4 – “Non-destructive testing of steel tubes – Part 4: Liquid penetrant inspection of seamless and welded steel tubes for the detection of surface imperfections.” This standard sets out the requirements for the penetrant testing of seamless and welded steel tubes, aimed at the detection of a material’s surface imperfections.
PN-EN ISO 10893-5
PN-EN ISO 10893-5 – “Non-destructive testing of steel tubes – Part 5: Magnetic particle inspection of seamless and welded ferromagnetic steel tubes for the detection of surface imperfections.” This standard sets out the requirements for the magnetic particle testing of ferro-magnetic seamless and welded steel tubes, aimed at detecting surface imperfections on the tube body and the end/bevel face at the ends.
PN-EN ISO 10893-8
PN-EN ISO 10893-8 – “Non-destructive testing of steel tubes – Part 8: Automated ultrasonic testing of seamless and welded steel tubes for the detection of laminar imperfections” This standard sets out the requirements regarding the automated ultrasonic detection of laminar imperfections in seamless and welded, except submerged arc-welded (SAW), steel tubes, in areas adjacent to the weld seam of welded steel tubes, and at the ends of seamless and welded tubes.
PN-EN ISO 11666
PN-EN ISO 11666 – “Non-destructive testing of welds – Ultrasonic testing – Acceptance levels.” This International Standard concerns ultrasonic testing of full penetration welded joints in ferritic steels with thicknesses from 8 mm to 100 mm. It can also be used to cover other types of welds, materials and thicknesses, provided that the tests are performed with necessary consideration of the geometry and acoustic properties of the component and an adequate sensitivity can be employed to enable the acceptance levels according to this International Standard.
PN-EN ISO 17025
PN-EN ISO 17025 – “General requirements for the competence of testing and calibration laboratories.” This document specifies the general requirements regarding the competence, impartiality and consistent operation of laboratories. It applies to all organisations conducting laboratory activities, regardless of the number of personnel.
PN-EN ISO 17636-1
PN-EN ISO 17636-1 – “Non-destructive testing of welds – Radiographic testing – Part 1: X- and gamma-ray techniques with film.” This standard sets out the general requirements for the radiographic testing of welded joints of metallic materials using industrial radiographic film techniques.
PN-EN ISO 17640
PN-EN ISO 17640 – “Non-destructive testing of welds – Ultrasonic testing – Techniques, testing levels, and assessment.” This standard sets out the techniques of manual ultrasonic testing of full penetration welds of metals with a thickness of ≥ 8 mm and low attenuation of ultrasonic waves at object temperatures from 0°C to 60°C.
It refers to welds in which both the base material and the weld metal have a ferritic structure. This document may be used to evaluate discontinuities for the purposes of approval of welded joints.
PN-EN ISO 23277
PN-EN ISO 23277 – “Non-destructive testing of welds – Penetrant testing – Acceptance levels”. This International Standard sets out the acceptance levels for indications from surface breaking imperfections detected by penetrant testing. The acceptance levels are intended to be used primarily for manufacture examination, but they can also be used for in-service inspection.
PN-EN ISO 23278
PN-EN ISO 23278 – “Non-destructive testing of welds – Magnetic particle testing – Acceptance levels”. This International Standard sets out the acceptance levels for indications of surface imperfections in ferromagnetic steels detected by magnetic particle testing. The acceptance levels are intended primarily for manufacture examination.
PN-EN ISO 5817
PN-EN ISO 5817 – “Welding – Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) – Quality levels for imperfections.” This International Standard provides quality levels according to imperfections in fusion-welded joints (except for beam welding) in all types of steel, nickel, titanium and their alloys. It applies to materials with a thickness of over 0.5 mm. It is also applicable to fully penetrated butt welds and all fillet welds.
PN-EN ISO 9712
PN-EN ISO 9712 – “Non-destructive testing – Qualification and certification of personnel who perform industrial non-destructive testing.” This International Standard specifies the requirements relating to the rules for the qualification and certification of personnel who performs industrial non-destructive testing (NDT).
PN-ISO – Polish Standard implementing an International Standard (by translation).
Penetrant – a highly wetting liquid with low surface tension and viscosity that penetrates into every opening and surface imperfection based on the phenomenon of capillarity. The penetrant contains a special dye which stands out well against the developer. The observation of the penetrant takes place in white light (where the penetrant’s dye is red or blue) or under UV-A radiation (where the dye is yellow-green and highly-fluorescent). Penetrants may be applied to a surface using e.g. a brush or sprayed by aerosol. The tested element may also be submerged in a special bath filled with the penetrant.
Penetrant testing PT
Penetrant testing PT – a method of non-destructive surface testing which takes advantage of the phenomenon of capillarity, which involves the penetration of a liquid (penetrant) with a low surface tension into narrow spaces (discontinuities), and its pulling using an absorbent fluid (developing fluid) It can be performed on alloy and non-alloy steels, steel castings, cast iron, aluminium, copper, nickel, titanium, plastics and other materials. The penetrant testing method is used to detect such discontinuities as porosity, cracks, cold shutting, etc. Additionally, it can be used for tightness testing.
Permission to conduct activities with sources of ionising radiation
Permission to conduct activities with sources of ionising radiation – Permissions to conduct activities involving exposure to sources of ionising radiation are issued by the President of the International Atomic Energy Agency on the basis of an application from the head of the organisational unit seeking to conduct such activities. The permission is issued for an indefinite period, unless the organisational unit applying for the permission files an application to issue a permission for a definite period.
Pipe ovality measurement
Pipe ovality measurement – a geometric measurement which allows to determine the shape of a pipe in terms of its symmetry and regularity, as well as the stresses present inside the tested pipe component. Despite modern technological advances, it is still difficult to obtain a perfectly round section shape in pressure components made of straight pipes which are then bent. Ovality measurement allows to estimate the operational durability of pipes.
Pitting – localised corrosion in the form of holes which often reach deep into the material.
Pitting corrosion
Pitting corrosion – involves the formation of local pitting as a result of an anodic reaction initiated by activating ions and a cathodic reaction in the presence of oxidising agents. The inside of the pit becomes anodic, which leads to metal dissolution. The area around the pit is cathodic, with oxygen reduction occurring there. Metals, such as stainless steel and aluminium, are particularly susceptible to this.
Porosity – a property of solids indicating the size and quantity of empty spaces in a material. Empty spaces are areas which contain no solid material, optionally only liquids – usually water or air.
Positive Material Identification PMI
Positive Material Identification PMI is a non-destructive testing method which allows to ascertain the chemical composition of elements without the need to take any samples. It uses a spectrometer featuring an X-ray lamp emitting radiation that induces metal atom excitation. The measurement result is obtained by calculating the photons (fluorescence) emitted by excited atoms.
Pressure Equipment Directive
Pressure Equipment Directive – the European Union directive aimed at standardising the regulations involving pressure equipment applicable in European Union Member States. It requires the governments of Member States to draw up regulations which comply with the Directive. The Directive refers to equipment with the maximum allowable pressure greater than 0.5 bar.
Product sector
Product sector – determines the types of products which can be subjected to non-destructive testing. These include: welded joints (including those made of composite materials), casts, forgings etc.
Proficiency testing
Proficiency testing – testing the results of a participant’s activities against an adopted criterion by means of interlaboratory comparisons.
Pyrometer – an instrument for contactless temperature measurement. In practice, this means that you can measure the temperature of an object or body without touching it, because the device works by detecting the thermal radiation levels emitted by the object.
pWPS – preliminary Welding Procedure Specification. A preliminary specification of the process of welding technology qualification which involves the performance of welding tests to prepare preliminary instructions and commence the welding of the actual test joint and evaluating its correctness by means of non-destructive testing.
Radioactive source
Radioactive source – a source of ionising radiation containing a radioactive material designed to take advantage of the material’s radioactivity.
Radiographic testing (RT)
Radiographic testing (RT) – a non-destructive testing method which facilitates the detection of discontinuities occurring inside the examined material. During RT, high-energy ionising radiation (X or γ) is directed at the object, and a sheet of radiographic film is placed behind it. After passing through the object, the radiation carries the internal image of the examined element as a projection of discontinuities (such as bubbles or solid inclusions) expressed in radiation dose differences, which is exposed on the radiographic image by blackening power variations. The final radiographic image is obtained by subjecting the film to specific photochemical processing (developing process). Any detected discontinuities are evaluated in the radiographic image according to specific criteria.
Radiological protection
Radiological protection – all the actions and activities aimed at preventing the exposure of people and the environment to ionising radiation, and if preventing such exposure is not possible, the actions aimed at limiting the detrimental health effects of such radiation.
Radiometer – an instrument recording the intensity of electromagnetic radiation for a given wavelength in any part of the electromagnetic radiation.
Remover – a liquid used for initial surface cleaning, removing excess penetrant and final cleaning. Depending on the type of applied penetrant, water or a special solvent may be used as the remover.
Röntgen radiation
Röntgen radiation – (X-rays, X-radiation) – a type of electromagnetic radiation which is generated during electron deceleration. In the electromagnetic spectrum, X-rays are found above ultraviolet, overlapping with the gamma rays.
Scope of approval
Scope of approval – detailed scope of testing methods covered by an UDT approval, included in an Appendix to the Laboratory Approval Certificate.
Se-75 – selenium-75, obtained by irradiation with shield material neutrons in a reactor 74Se. The irradiation process in the reactor takes a relatively long time (usually several months). The source of Se-75 is used in radiographic testing for scanning welds, forgings and casts on industrial structures.
Sentinel Delta
Sentinel Delta – a container for transporting a radiation source to a specific exposure position, as required, and for protecting and covering it when not in use. Maximum packaging weight – 22 kg with casing, 20 kg without casing.
Sentinel Elite
Sentinel Elite – a container for transporting a radiation source to a specific exposure position, as required, and for protecting and covering it when not in use. Maximum packaging weight – 18 kg with casing, 16 kg without casing.
Solid inclusions
Solid inclusions – foreign bodies trapped in the weld seam. These include slag, flux, oxides and metallic inclusions.
Spatter – fine metal particles coming from the core of the welding arc and deposited on the elements of the welding gun – the gas nozzle and the contact tip. Welding spatter may also deposit on the welded material.
Specification – a document which specifies requirements, design, behaviour or other properties in a complete, accurate and verifiable manner.
Spectrometer – a specialised instrument for analysing the elemental composition of a substance using the recorded spectrum.
Spectrometer – an apparatus for analysing the elemental composition of a substance on the basis of the recorded spectrum.
Stepped calibration block for UTT
Stepped calibration block for UTT – a calibration block used in ultrasonic thickness testing used for calibrating the time base for longitudinal waves. Used for calibrating ultrasonic thickness gauges.
Test piece
Test piece – a welded joint made to test the properties of the materials used in the welding process, the correctness of the technological process or the qualifications of the welder producing the joint.
Test plate
Test plate – a welded joint made to test the properties of the materials used in the welding process, the correctness of the technological process or the qualifications of the welder producing the joint.
Test report
Test report – a document which specifies the objective and plan of the test and describes the planned procedure and conditions of the test.
Testing – experimental or theoretical work conducted primarily to obtain new knowledge about the principles of phenomena and observable facts without bias in favour of a specific application or use.
Testing laboratory
Testing laboratory – an entity which conducts testing to verify the state of an existing structure and make predictions about its durability, workmanship and safe usage.
Thermo-hygrometer – an instrument for measuring air humidity and temperature. Its principle of operation is based on the constant operation of a special sensor which records changes in conductivity and resistivity depending on air humidity.
Traceability – the quality of a measurement or measurement standard which allows relating it to stated references, usually national standards or international measurement units, by means of an unbroken chain of comparisons all having stated uncertainties.
Type 2 PT reference block
Type 2 PT reference block – a type 2 reference block used to perform verification activities (performance checking) of a penetrant system.
UDT – Office of Technical Inspection. A Polish institution established to ensure the safety of operation of all technical installations and equipment which are legally subject to technical inspection. UDT’s activities involve both certification – UTD-CERT and training – UDT academy.
UV light meter
UV light meter – a device for measuring ultraviolet light. These are specialised meters for measuring the proportion of harmful UV-C radiation – wavelength: 100 – 280 nm, UV-B – wavelength: 280 – 315 nm, UV-A – wavelength: 315 – 400 nm.
Ultrasonic flaw detector
Ultrasonic flaw detector – a device used to conduct ultrasonic testing. The use of ultrasonic flaw detectors allows identifying, selecting, recording and evaluating flaws, and measuring material properties. This is possible due to ultrasonic wave propagation, reflection, refraction at the boundary of two media, interference and diffraction. The discontinuity in material structure causes wave reflection, which is immediately detected and recorded by the flaw detector.
Ultrasonic testing UT
Ultrasonic testing UT – a non-destructive testing method which allows detecting and evaluating readings (imperfections) occurring inside the tested object. This method facilitates determining the location and scale of imperfections inside the material. It detects imperfections using ultrasonic waves, which usually have frequencies of 0.5–6 MHz. An ultrasonic head is used to emit ultrasonic waves that penetrate into the material. Discontinuities in the tested element reflect a part of the beam, which returns to the head (transducer). The testing technique is based on observing the impulses reflected from material discontinuities on the oscilloscope screen.
Ultrasonic thickness gauge
Ultrasonic thickness gauge – a device measuring the propagation speed of a longitudinal ultrasonic wave in a given material and then converting this value into material thickness expressed in millimetres or inches according to a specific mathematical formula.
Ultrasonic thickness testing UTT
Ultrasonic thickness testing UTT – a non-destructive testing method which involves longitudinal ultrasonic waves penetrating the material and a measurement of the time in which the wave passes through the object.
Undercut – an irregular groove in the base material created during welding at the bead edge or in the previously ordered metal of the seam.
V1 calibration block (V1)
V1 calibration block (V1) – a calibration block used in ultrasonic testing to determine the probe angle, the energy of the apparatus-normal probe system, evaluate the resolution of normal probes, and adjust the sensitivity of normal and angle probes.
V2 calibration block (V2)
V2 calibration block (V2) – a calibration block used in ultrasonic testing to determine the probe angle, calibrate the time base for shear waves and measure the energy of angle probes.
Vacuum box
Vacuum box – leak testing using a vacuum box. Vacuum box testing is an effective technique of testing welded joints. It is a relatively fast testing method which may be performed without interfering with other production activities. The test uses a vacuum box featuring rubber gaskets along its open bottom for mounting and an upper cover made of transparent Plexiglas. The tested weld section is coated with a foam solution and then covered with the box inside which slight negative pressure is generated. If a leak is present in the tested weld, atmospheric air penetrates through it (from the other side of the weld) into the box, which is visible as soap bubbles on its surface in the location of the leak.
Vacuum pump
Vacuum pump – a device for removing gas (producing negative pressure) in a closed space. It is used to produce negative pressure during leak testing using bubble emission techniques.
Validation – confirmation, by providing objective proof, that the requirements of specific use or application have been complied with.
Vickers hardness HV
Vickers hardness HV – a hardness measure of metals, cemented carbides and ceramics obtained on the basis of a test. HV designates the hardness value obtained according to the Vickers method. Vickers hardness is the most widely used measure of material hardness. This method is used primarily for measuring the hardness of welded joints.
Vickers hardness reference block
Vickers hardness reference block – a calibration block for Vickers hardness scale (HV) in portable hardness testers.
Vision test
Vision test – a measurement of different abilities of seeing light within the field of vision of the person being examined, which is performed by checking how well he or she identifies objects against a plain background.
Visual testing VT
Visual testing VT – a basic method of non-destructive surface testing performed before any other non-destructive tests. Visual testing only allows the detection of imperfections formed on the surface of welded joints. Observations are made from the side of the face and the root (if access is provided) using the naked eye or with mirrors, loupes, etc.
WPQR (Welding Procedure Qualification Record).
WPQR (Welding Procedure Qualification Record). This document authorises a company to conduct welding work on stated materials with specific thicknesses (for tubes, also diameters) by means of its own welding technology.
WPS (Welding Procedure Specification)
WPS (Welding Procedure Specification) – instructions for the welder prepared on the basis of the tested and proven welding technology, WPQR (Welding Procedure Qualification Record). It includes at least the basic technological guidelines, i.e. the digital signage of the welding procedure, the surface preparation method, a schematic drawing of the welded joint, the parameters used during welding and information regarding the welding filler, identifying data, information on the welded material and other specific requirements connected with the method of welding.
WUDT – UC – The requirements and guidelines of the Office of Technical Inspection regarding pressure equipment subject to technical inspection pursuant to the Act of 21 December 2000 on Technical Inspection and the Regulation of the Council of Ministers of 7 December 2012 on the types of technical devices subject to technical inspection.
Weld face
Weld face – the outer surface of the weld on the side of making the weld.
Weld gauge
Weld gauge – an instrument for measuring the dimensions of the gap, bevel angle and width, height and depth of the undercut. It consists of the main scale, a height meter, an undercut depth meter and a multi-purpose meter.
Weld quality level
Weld quality level – involves quality categories of welds specified on the basis of the types and sizes of welding imperfections. The quality level is determined when performing visual inspection, ultrasonic, radiographic, penetrant and magnetic particle testing.
Weld root
Weld root – the outer surface of the weld bead opposite the face, which is present in one-sided butt welded joints.
Weld, welded joint
Weld, welded joint – a type of joint produced in the physical process of combining metals by means of their local melting and solidification. Used e.g. to join metals (primarily steel) and plastics. Welding usually involves the addition of a welding filler, i.e. an additional material which melts along with the parent material and fills the joint.
Welding – a method of joining various types of metals. There are a variety of welding techniques which allow joining nearly all kinds of ferrous and non-ferrous metals. Various kinds of filler metals, which include welding rods, are used to produce a weld, or joint.
Welding defect
Welding defect – a welding imperfection that fails to fulfil the specified acceptance criteria. An example of a welding defect is weld cracking, which is unacceptable under any quality level as per PN-EN ISO 5817.
Welding imperfection
Welding imperfection – an imperfection of the weld that deviates from perfect quality in terms of appearance and shape.
Welding procedure qualification
Welding procedure qualification – the verification of correctness of a welding procedure described in the preliminary Welding Procedure Specification (pWPS) conducted by means of specific tests of the welded joint produced according to the pWPS.
White contrast paint
White contrast paint – a white chemical substance used as a contrast for performing magnetic particle using colour contrast.
X-ray apparatus
X-ray apparatus – a device generating X-radiation.
X-ray film viewer
X-ray film viewer – a device for viewing radiographic images (X-ray film) in transmitted light; it is box-shaped and has a uniformly backlit matte screen, against which images are viewed.
X-ray tube
X-ray tube – a man made source of X-rays, a vacuum tube featuring a pair of electrodes (anode and cathode) in the form of a tungsten spiral filament. When high voltage is applied to the electrodes, it accelerates the positive ions (an ionic X-ray tube) or electrons detaching from the cathode (an electron X-ray tube). While bombarding the electrode (cathode in the ionic tube and anode in the electron tube), these particles emit deceleration radiation which is an X-ray quantum flux with a continuous energy spectrum. Deceleration radiation is generated due to the interaction of the particle with the electrostatic fields of the nuclei and electrons in the matter forming the anode. Electrons which hit the anode are decelerated, which generates X-rays.
X-ray tube
X-ray tube – a device generating X-radiation.

The above glossary has been drawn up on the basis of general information available online.