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A global view on standardization in ultrasonic testing Udo Schlengermann Krautkrämer GmbH, Hürth, Germany Contact

Abstract

Technical standards not only open markets, but can also be barriers for trade. Global markets are more a dream than reality, cultures and economical potential of continents and countries greatly differ. But global manufacturing is reality. Supply parts from all regions of the world are assembled into final products. This global trade leads to a growing demand for agreements on common technical specifications, especially in the sector of nondestructive testing which is directly related to quality and safety.

Keywords: Nondestructive testing, ultrasonic testing, qualification, certification, international standardization, world trade zones, technical barrier treaty.

Introduction

Standards in the field of nondestructive testing can be looked upon from very different points of view: the methods are not material specific, the techniques are not restricted to special industries nor to special products. Ultrasonic examinations, based on the the same physical phenomena, can be used in very different fields such as medical diagnosis and therapy, in chemical treatment and in mechanical engineering. There are not many similarities as seen from the point of view of specific product requirements which require ultrasonic inspection. There are techniques for metals and plastics, on detection and on sizing of defects, for material characterization and for quality estimation of bonds. Standards describe the state-of-the art and have been integrated into different systems of technical education and therefore they may be different although they are related to the same object, e.g. ultrasonic testing of butt welds in steel. Nevertheless we are in the millenium of global manufacturing now and have to construct an accepted worldwide system of standards all aspects in quality management so far as nondestructive testing, especially ultrasonic testing, is concerned.

Standards and trade

Nondestructive testing techniques are used under two main aspects:

• Quality management
  Where quality in general means customer's satifaction when using standardized products without any annoyance and where the manufacturer does not loose money making products which cannot be sold.
• Safety
  Safety related standards are for the protection of the individual as well as for people in general.

But if <quality> and <safety> are defined in different ways in some parts of the world, you get protected markets, separated by standards which build up socalled non-tariff barriers.

Recent studies have shown [1] that international standards have a strong positive impact on the increase in foreign trade, e.g. more than patents, whereas national standards have a more negative effect.

To understand the development of international standards in NDT it is important to know the political and economical background related to the main aspects of and in world trade. The Technical Barrier Treaty (TBT) of World Trade Organization (WTO) by a special agreement tries to tear down these non-tariff barriers by supporting international technical standardization in free-trade zones. If we take a look at these zones we find 5 main blocks:

APEC	Asia-Pacific Economic Cooperation Forum, with 21 members, from Australia to Vietnam, including Japan, Russia and the United States of America, having an equal balanced trade flow in 2000 of 2592 billion US$ in exports and 2581 billion US$ in imports.
EU	European Union, with 19 members, from Austria to the United Kingdom, including EFTA countries, having a trade flow in 2000 of 813 billion US$ in exports and 801 US$ in imports.
Cairns Group	with 15 members from Argentina to Uruguay, including Australia but more an agricultural market, trade flow in 2000 of 577 billion US$ in exports and 549 billion US$ in imports.
NAFTA	North-American Free Trade Agreement, with 3 members, Canada, United States of America, Mexico, and a trade flow in 2000 of 1017 billion US$ in exports and 1277 billion US$ in imports. But this zone also concentrates more on agriculture, environment and labour.

From this list you can see, that the impact on technical standardization will come from only three zones: North-America, Asia-Pacific Region and Europe. For example these are exactly the global players in the automotive industry, but this also applies to other industries.

If the zones and the relevant industries are influenced by the United States, e.g. civil aviation, automotive, oilfield equipment, we will find the main US standards systems: API, ASME, ASTM, ASW and for NDT personnel ASNT, i.e. the standard system is made by a lot of different non-profit organizations. In Europe the system is quite different: A political agreement was made to construct the European Union as a single Market by tearing down tariff and non-tariff boundaries, e.g. by generating a unique system of technical standards under the directives of the European Commission. This means that there is a political demand for new or harmonized standards (mandated standards) to fill the frame-work given by the directives. An example is the Pressure Equipment Directive, PED (97/23EC) where the inspection sector has been filled with new standards on weld testing using all NDT methods, including ultrasonics.

International organizations for standardization

We now have identified the main global trade zones and the big industrial groups having their headquarters there.

• Depending on their residence some of them try to export their national standards, for example API (American Petroleum Institute, ASTM (American Society for Testing and Materials) or SAE (Society of Automotive Engineers).
• Others cooperate in international engineering societies like IIW (International Institute of Welding), IISI (International Iron and Steel Institute) or IEEE (Institute of Electrical and Electronic Engineers).

But there are only two real international standardizing organizations:

ISO/ IEC	International Organization for Standardization/ International Electrotechnical Commission
CEN/ CENELEC	European Committee for Standardization/ European Comittee for Electrotechnical Standardization.

Some additional remarks on international technical standards should be made. In general standards are no laws, e.g. standards are always non-mandatory. But they can be referenced in laws thus making them quasi legal documents which are mandatory. Systems of standards are usually called codes. Sometimes codes are used as legal documents. The most important example in NDT is the ASME Boiler & Pressure Vessel Code which has a counter part by the code developed according to the European Pressure Equipment Directive.

Not all applications of nondestructive testing can be covered by international standards. Military/Defense (military alliances only) and Nuclear Safety are (unfortunately) strictly under national law.
But the remaining can be treated worldwide.

A systematic standards system for nondestructive testing

A scheme for building such a modular system of standards is shown in Figure 1. If you compare the traditional national systems against this scheme you will recognize some missing parts in your national system.
The main characteristics of the modules of the standards system in Figure 1 are:

1. The basis must be general standards on quality for products and services accompanied by general standards for laboratories and personnel (specialized for industrial sectors) and for the basis for communication (same language).
2. To get reliable results there must be agreements by standards on the general principles of an NDT method (ultrasonics, radiography, die penetrant testing, etc.) and for the equipment used (instrument, probes) and for calibration blocks and calibration procedures.
3. If the test object and the purpose of the inspection (quality class) are defined, you need standards to select the appropriate method, e.g. ultrasonics instead of radiography, matched to a given quality class of the test object.
4. If the decision for a special nondestructive technique has been made, there must be a standard on how to accomplish an examination using this technique, e.g. an ultrasonic weld inspection.
5. There must be at least standards on acceptance criteria related to the object to be tested and to the method used, e.g. to evaluate the results of an ultrasonic inspection on a fillet weld in steel.

Fig 1: Scheme of a complete standards system for nondestructive testing.

According to the scheme in Figure 1, Figure 2 is filled with the existing CEN standards, together with ISO standards if available. The appropriate Australian standards are mentioned in the text:

1. General quality standards on products and laboratories are:
   EN ISO 9000 series: Quality management and quality assurance standards - Guidelines;
   EN ISO/IEC 17025: General requirements for the competence of testing and calibration laboratories.
2. For NDT personnel we find not identical standards:
   EN 473: Nondestructive testing - Qualification and certification of NDT personnel - General principles;
   ISO 9712: Nondestructive Testing - Qualification and certification of personnel;
   AS 3998: Qualification of NDT personnel;
   Terminology is dealt with in:
   EN 1330-1: Nondestructive testing - Terminology - Part 1: General terms;
   EN 1330-2: Nondestructive testing - Terminology - Part 2: Terms common to the nondestructive testing methods;
   EN 1330-4: Nondestructive testing - Terminology - Part 4: Terms used in ultrasonic testing;
   ISO 5577: Nondestructive testing - Ultrasonic inspection - Vocabulary;
3. General principles of ultrasonic examinations are described in:
   EN 583-1: Nondestructive testing - Ultrasonic examination - Part 1: General principles.
   EN 583-2: Nondestructive testing - Ultrasonic examination - Part 2: Sensitivity and range setting.
   EN 583-3: Nondestructive testing - Ultrasonic examination - Part 3: Transmission technique;
   EN 583-4: Nondestructive testing - Ultrasonic examination - Part 4: Examination for discontinuities perpendicular to the surface;
   EN 583-5: Nondestructive testing - Ultrasonic examination - Part 5: Characterization and sizing of discontinuities;
   ENV 583-6: Nondestructive testing - Ultrasonic examination - Part 6: Time-of-flight diffraction technique for detection and sizing of discontinuities;
   For equipment we find the standards:
   EN 12668-1: Nondestructive testing - Characterization and verification of ultrasonic examination equipment - Part 1: Instruments;
   EN 12668-2: Nondestructive testing - Characterization and verification of ultrasonic examination equipment - Part 2: Probes;
   EN 12668-3: Nondestructive testing - Characterization and verification of ultrasonic examination equipment - Part 3: Combined equipment.
   The following ISO-standards are not equivalent to EN-standards:
   ISO 12710: Nondestructive testing - Ultrasonic inspection - Evaluation of electronic characteristics of instruments;
   ISO 18175: Nondestructive testing - Evaluating performance characteristics of ultrasonic pulse-echo testing instruments without the use of electronic instruments;
   ISO 10375: Nondestructive testing - Ultrasonic inspection -Characterization of search unit and sound field;
   ISO 12715: Ultrasonic nondestructive testing - Reference blocks and test procedures for the characterization of contact search unit beam profiles.
   For calibration blocks there are the following standards:
   EN 27963 (identical to ISO 7963): Welds in steel - Calibration block no 2 for ultrasonic examination of welds;
   EN 12223: Nondestructive testing - Ultrasonic examination - Specification for calibration block No 1 (not identical to ISO 2400);
   AS 2083: Calibration blocks for ultrasonic testing.
4. A standard for selection of NDT methods concerning weld testing is:
   EN 12062: Nondestructive examination of welds - General rules for metallic materials. (will be ISO 17635).
5. To follow the example of welds in steel, the procedure for ultrasonic testing is given in:
   EN 1714: Nondestructive examination of welds - Ultrasonic examination of welded joints.(will be ISO 17640).
   AS 2207: Ultrasonic testing of fusion welded joints of carbon steel.
6. Evaluation of weld testing results and acceptance criteria for ultrasonic testing of welds in steel are dealt with in:
   EN 1712: Nondestructive examination of welds - Ultrasonic examination of welded joints - Acceptance criteria (will be a new ISO work item);
   EN 1713: Nondestructive examination of welds - Ultrasonic examination - Characterization of indications in welds (will be a new ISO work item).

Fig 2: Standards system for the ultrasonic examination of welds in steel.

Further information on international standards for weld testing is given in [2]. The problems of international standards on the qualification of NDT personnel are discussed in [3].

An overview of comparable international standards in ultrasonic testing (excluding acoustic emission) can be found in Table 1.

CEN Standard		ISO Standard		Remarks
EN 473	Nondestructive testing - Qualification and certification of NDT personnel - General principles	ISO 9712	Nondestructive testing - Qualification and certification of personnel	comparable
EN 1330-1	Nondestructive testing - Terminology - part 1: General terms
EN 1330.2	Nondestructive testing - Terminology - part 2: Terms common to the nondestructive testing methods
EN 1330-4	Nondestructive testing - Terminology - part 4: Terms used in ultrasonic testing	ISO 5577	Nondestructive Testing - Ultrasonic inspection - Vocabulary	comparable
EN 1712	Nondestructive examination of welds - Ultrasonic examination of welded joints - Acceptance levels	ISO	New work item
EN 1713	Nondestructive ultrasonic examination - Characterization of indications in welds	ISO	New work item
EN 1714	Nondestructive examination of welds - Ultrasonic examination of welded joints	ISO 17640	Nondestructive examination of welds - Ultrasonic examination of welded joints	comparable
EN 10256	Nondestructive testing of steel tubes - Qualification and competence of level 1 and 2 nondestructive testing personnel	ISO 11484	Steel tubes for pressure purposes - Qualification and certification of nondestructive testing personnel	comparable
EN 12062	Nondestructive examination of welds - General rules for metallic materials	ISO 17635	Nondestructive examination of welds - General rules for metallic materials	equivalent
EN 12223	Nondestructive testing - Ultrasonic examination - Specification for calibration block no 1	ISO 2400	Welds in steel - Reference block for the calibration of equipment for ultrasonic examination	comparable
EN 13296	Testing concrete - Determination of ultrasonic pulse velocity	ISO 8047	Concrete, hardened - Determination of ultrasonic pulse velocity	comparable
EN 13919-1	Welding - Electron and laser-beam welded joints - Guidance on quality levels for imperfections - part 1: Steel	ISO 13919-1	Welding - Electron and laser-beam welded joints - Guidance on quality levels for imperfections	identical
EN 13919-2	Welding - Electron and laser-beam welded joints - Guidance on quality levels for imperfections - part 2: Aluminium and ist weldable alloys	ISO 13919-2	Welding - Electron and laser-beam welded joints - Guidance on quality levels for imperfections - part 2: Aluminium and ist weldable alloys	identical
EN 25817	Arc-welded joints in steel - Guidance on quality levels for imperfections	ISO 5817	Arc-welded joints in steel - Guidance on quality levels for imperfections	identical
EN 27963	Welds in steel - Calibration block no 2 for ultrasonic examination of welds	ISO 7963	Welds in steel - Calibration block no 2 for ultrasonic examination of welds	identical
EN 30042	Arc-welded joint in aluminium and its weldable alloys - Guidance on quality levels for imperfections	ISO 10042	Arc-welded joint in aluminium and its weldable alloys - Guidance on quality levels for imperfections	identical
Table 1: List of comparable international standards on ultrasonic testing.

Special standards on NDT personnel are listed in Table 2.

CEN Standard		ISO Standard		Remarks
EN 473	Nondestructive testing - Qualification and certification of NDT personnel - General principles	ISO 9712	Nondestructive testing - Qualification and certification of personnel	comparable
EN 10256	Nondestructive testing of steel tubes - Qualification and competance of level 1 and 2 nondestructive testing personnel	ISO 11484	Steel tubes for pressure purposes - Qualification and certification of nondestructive testing personnel	equivalent
EN	Limited NDT	ISO	Limited NDT	started
Table 2: Standards on qualification of nondestructive testing personnel.

A further example of successfully established international standards (by international agreement) is shown in Table 3: The field of automated ultrasonic testing of steel tubes.

CEN Standard		ISO Standard		Remarks
EN 10246-6	Nondestructive testing of steel tubes - part 6: Automatic full peripheral ultrasonic testing of seamless steel tubes for the detection of transverse imperfections	ISO 9305	Seamless steel tubes for pressure purposes - Full peripheral ultrasonic testing for the detection of transverse imperfections	equivalent
EN 10246-7	Nondestructive testing of steel tubes - part 7: Automatic full peripheral ultrasonic testing of seamless and welded (except submerged-arc welded steel tubes for the detection of longitudinal imperfections	ISO 9303	Seamless and welded (except submerged-arc welded) steel tubes for pressure purposes - Full peripheral ultrasonic testing for the detection of longitudinal imperfections	Equivalent
EN 10246-8	Nondestructive testing of steel tubes - part 8: Automatic ultrasonic testing of the weld seam of electric welded steel tubes for the detection of longitudinal imperfections	ISO 9764	Electric resistance and induction welded steel tubes for pressure purposes - Ultrasonic testing of the weld seam for the detection of longitudinal imperfections	equivalent
EN 10246-9	Nondestructive testing of steel tubes - part 9: Automatic ultrasonic testing of the weld seam of submerged-arc welded steel tubes for the detection of longitudinal and/or transverse imperfections	ISO 9765	Submerged-arc welded steel tubes for pressure purposes - Ultrasonic testing of the weld seam for the detection of longitudinal and/or transverse imperfections	equivalent
EN 10246-13	Nondestructive testing of steel tubes - part 13: Automatic full peripheral ultrasonic thickness testing of seamless and welded (except submerged-arc welded) steel tubes	ISO 10543	Seamless and hot-stretch-reduced welded steel tubes for pressure purposes - Full peripheral ultrasonic thickness testing	equivalent
EN 10246-14	Nondestructive testing of steel tubes - part 14: Automatic ultrasonic testing of seamless and welded (except submerged-arc welded) steel tubes for the detection of laminar imperfections	ISO 10124	Seamless and welded (except submerged-arc welded) steel tubes for pressure purposes - Ultrasonic testing for the detection of laminar imperfections	equivalent
EN 10246-15	Nondestructive testing of steel tubes - part 15: Automatic ultrasonic testing of strip/plate used in the manufacture of welded steel tubes for the detection of laminar imperfections	ISO 12094	Welded steel tubes for pressure purposes - Ultrasonic testing for the detection of laminar imperfections in strips/plates used in the manufacture of welded tubes	equivalent
EN 10246-16	Nondestructive testing of steel tubes - part 16: Automated ultrasonic testing of the area adjacent to the weld seam of welded steel tubes for the detection of laminar imperfections	ISO 13663	Welded steel tubes for pressure purposes - Ultrasonic testing of the area adjacent to the weld seam for the detection of laminar imperfections	equivalent
EN 10246-17	Nondestructive testing of steel tubes - part 17: Ultrasonic testing of tube ends of seamless and welded steel tubes for the detection of laminar imperfections	ISO 11496	Seamless and welded steel tubes for pressure purposes - Ultrasonic testing of tube ends for the detection of laminar imperfections	equivalent
Table 3: Standards on automated ultrasonic inspection of steel tubes.

The first attempts are made to insert American standards into the ISO system, especially API specifications (delivery conditions), where NDT is included, see Table 4.

ISO Standard		US Specification		Remarks
ISO 3183-1	Petroleum and natural gas industries - steel pipes for pipelines - Technical delivery condition - part 1: Pipes of requirement class A	API Spec 5L	Line pipe	comparable
ISO 3183-3	Petroleum and natural gas industries - steel pipes for pipelines - Technical delivery condition - part 1: Pipes of requirement class C	API Spec 5L	Line pipe	comparable
ISO 10375	Nondestructive testing - Ultrasonic inspection - Characterization of search unit and sound field	ASTM E1065	Standard guide for evaluating characteristics of ultrasonic search units	Not identical
ISO 11960	Petroleum and natural gas industries - Steel pipes for use as casing or tubing for wells	API Spec 5CT	Casing and tubing	comparable
ISO 11961	Petroleum and natural gas industries - Steel pipes for use as drill pipe - Specification	API Spec 5D	Drill pipe	comparable
ISO 12709	Nondestructive testing - Ultrasonic inspection - Detection and evaluation of discontinuities by the immersed pulse-echo ultrasonic method	ASTM E214	Standard practice for immersed ultrasonic examination by the reflection method using pulsed longitudinal waves	Not identical
ISO 12710	Nondestructive testing - Ultrasonic inspection - Evaluating electronic characteristics of instruments	ASTM E1324	Standard guide for measuring some electronic characteristics of ultrasonic examination instruments	comparable
ISO 12715	Ultrasonic nondestructive testing - Reference blocks and test procedures for the characterization of contact search unit beam profiles	ASTM	Contents from several specifications	comparable
ISO 18175	Nondestructive testing - Evaluating performance characteristics of ultrasonic pulse-echo testing instruments without the use of electronic measurement instruments	ASTM E317	Standard practice for evaluating performance characteristics of ultrasonic pulse-echo examination instruments without the use of electronic measurement instruments	comparable
Table 4: Comparable ISO standards and United States specifications on ultrasonic testing.

Principles of international standardization

As explained, the international standardization does not simply mean acceptance of national standards to global markets. The WTO-TBT supports free trade by applying pressure against national certification schemes and protective technical barrier procedures, and promotes the use of international agreed standards under 6 principles:

1. Transparency	(i.e. access for all interested parties to the standardizing process);
2. Openness	(i.e. open for all WTO members);
3. Neutrality and consensus	(i.e. there are no privileged groups);
4. Effectivity and relevance	(i.e. standards have to be shaped to market needs);
5. Coherency	(i.e. double work or operlapping work has to be avoided);
6. Development aspects	(i.e. access and benefits for developing countries).

ISO/IEC and other international organizations such as OIML and OECD are observers to the WTO-TBT.

Countries who want to join the European Union, e.g. have to sign the Protocol on European Conformity Agreement (PECA), before entering. It means declaring implementation of the existing directives of the European Commission into their national technical rules, before entering the EU.

ISO and CEN have an agreement (Vienna agreement) on mutual information on their work, e.g. a stand-still agreement, i.e. not to start work in the same field if the other organization is already working on it. Furthermore there is an agreement to accept existing standards in the other organization if possible, to get identical - at least equivalent - standards. The growing Table 1 shows the preliminary results. There are different voting procedures in CEN and ISO to quickly accept new standards, e.g. the unique voting procedure or the parallel voting in both organizations.

The national NDT societies and their international federations, such as the European Federation for NDT (EFNDT) and the International Committee for NDT (ICNDT) can support this process of developing global NDT standards, especially in the sector of personnel qualification and certification.

Standards and business

As a kind of summary the following statements underline why international standardization is important in nondestructive testing as a worldwide business:

• Standardization is business (it makes markets);
• Taking part in international standardization supports your own exports;
• Creating products and services according to international standards gives benefits to customers and producers, and increases key competence.

References

1. Deutsches Institut für Normung (DIN):
   Gesamtwirtschaftlicher Nutzen der Normung - Zusammenfassung der Ergebnisse - Wissenschaftlicher Endbericht mit praktischen Beispielen.
   (Total economical profit of standardization - Executive summary with practical examples)
   Berlin, Beuth-Verlag (2000) ISBN 3-410-14856-6.
2. Zentner, F.:
   Framework conditions and interconnections between European and International standardization in the field of welding.
   Welding in the World 44 (2000) 4, 3-9.
3. Onoe, M.:
   Role of ISO in NDT certification and standardization.
   CSNDT Journal (2000) 2, 6-14.
There is no science without measurement
There is no quality without testing
There is no global market without global standards

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