CEN/TC 138/WG 7 - Acoustic emission testing

This document specifies the general principles required for leak detection by acoustic emission testing (AT). It is addressed to the application of the methodology on structures and components, where a leak flow as a result of pressure differences appears and generates acoustic emission (AE).
It describes phenomena of the AE generation and influence of the nature of fluids, shape of the gap, wave propagation and environment.
The different application techniques, instrumentation and presentation of AE results are discussed. Also included are guidelines for the preparation of application documents which describe specific requirements for the application of the acoustic emission testing.
Annex A gives procedures for some leak-testing applications.

This document specifies general requirements for in-service acoustic emission (AE) monitoring. It relates to detection, location and grading of AE sources with application to metallic pressure equipment and other structures such as bridges, bridge ropes, cranes, storage tanks, pipelines, wind turbine towers, marine applications, offshore structures. The monitoring can be periodic, temporary or continuous, on site or remote-controlled, supervised or automated. The objectives of AE monitoring are to define regions which are acoustically active as a result of damage or defect evolution.

This document specifies test routines for the periodic verification of the performance of acoustic emission (AE) test equipment, i.e. sensors, pre-amplifiers, signal processors, external parametric inputs.
It is intended for use by qualified personnel to implement an automated verification process.
Verification of the measurement characteristics is advised after purchase of equipment, in order to obtain reference data for later verifications. Verification is also advised after repair, modifications, use under extraordinary conditions, or if one suspects a malfunction.
The procedures specified in this document do not exclude other qualified methods, e.g. verification in the frequency domain. These procedures apply in general unless the manufacturer specifies alternative equivalent procedures.
Safety aspects of equipment for use in potentially explosive zones are not considered in this document.

This European Standard is concerned only with terms used specifically in acoustic emission testing (AT) and these fall into four parts:
-   terms relating to the physical phenomenon;
-   terms relating to the detection of the acoustic emission;
-   terms relating to the measured characteristics of the signal(s);
-   terms relating to acoustic emission applications.

This European Standard describes the method for conducting acoustic emission testing (AT) of metallic pressure equipment during acceptance pressure testing using a planar location method. This standard is applicable also for subsequent tests for requalification. General principles of Acoustic Emissions are described in EN 13554.
The objectives of the AE testing are to provide 100 % volumetric testing to define regions of the structure which are acoustically active with burst type AE, e.g. as a result of evolution of sub-critical discontinuities, thus increasing the reliability of the acceptance test. The test provides a reference map for comparison with results of future tests.

This European Standard specifies the general principles required for the acoustic emission testing (AT) of industrial structures, components, and different materials under stress and for harsh environment, in order to provide a defined and repeatable performance. It includes guidelines for the preparation of application documents, which describe the specific requirements for the application of the AE method.
Unless otherwise specified in the referencing documents, the minimum requirements of this European Standard are applicable.

This European Standard describes the general principles of acoustic emission (AE) testing of materials, components and structures made of FRP with the aim of:
-   materials characterisation;
-   proof testing/manufacturing quality control;
-   retesting/in-service inspection;
-   health monitoring.
When AE testing is used to assess the integrity of FRP materials, components or structures or identify critical zones of high damage accumulation or damage growth under load this standard further describes the specific methodology (e.g. suitable instrumentation, typical sensor arrangements, location procedures, etc.).
It also describes available, generally applicable evaluation criteria for AE testing of FRP and outlines procedures for establishing such evaluation criteria in case they are lacking.
NOTE   The structural significance of the AE may not in all cases definitely be assessed based on AE evaluation criteria only but may require further inspection and assessment (e.g. with other non-destructive test methods or fracture mechanics calculations).
This standard also recommends formats for the presentation of AE test data that allow the application of qualitative and quantitative evaluation criteria, both on-line during testing and by post test analysis, and that simplify comparison of AE test results obtained from different test sites and organisations.

This European Standard describes acoustic emission testing (AT) on metallic surroundings filled with liquids for the detection of corrosion processes that are active at the time of the test. It is applicable to metallic storage tanks, such as those used in the chemical and petrochemical industry.
The results provide a qualitative statement regarding the condition of the test object and a recommendation regarding the maximum allowable duration of the follow-on service period, based on the AT indications and additional information in order to characterize the AT indications.
In the case of flat bottomed storage tanks (FBST) the procedure described within this standard provides testing of the complete bottom, the tank shell up to the filling height and in case of a floating roof tank also the roof sheets in contact with the stored liquid.
As for every application of acoustic emission testing, the measured data contain information regarding active sources. An ongoing corrosion process, such as general corrosion and localized corrosion defined in EN ISO 8044, leading to progressive loss of wall thickness will be detected. A corrosion process which has stopped does not produce acoustic emission and will therefore not be detected at the time of test.

The purpose of this standard is to describe the methods for conducting an acoustic emission (AE) examination of metallic pressure equipment during acceptance pressure testing using a zone location procedure. General principles of Acoustic Emissions are described in EN 13554.
The objectives of the AE testing are to provide 100 % volumetric testing to define and grade zones of the structure which are acoustically active with burst type AE. The method should be regarded as supplementary to planar location. Planar location provides the source identification and characterisation. Zone location may also be applied in such cases where location of AE sources by planar location procedures according to EN 14584 is not possible.
The method identifies the need for further evaluation or follow-up by other NDT in localized zones.

This part of the standard describes the main components that constitute an acoustic emission (AE) monitoring system comprising: - detection, - signal conditioning, - signal measurement, - analysis and output of results.

ISO 18081:2016 specifies the general principles required for leak detection by acoustic emission testing (AT). It is addressed to the application of the methodology on structures and components, where a leak flow as a result of pressure differences appears and generates acoustic emission (AE).
It describes phenomena of the AE generation and influence of the nature of fluids, shape of the gap, wave propagation and environment.
The different application methods, instrumentation and presentation of AE results is discussed. Also included are guidelines for the preparation of application documents which describe specific requirements for the application of the AE method.
Different application examples are given.
Unless otherwise specified in the referencing documents, the minimum requirements of this International Standard are applicable.

This part of the standard specifies methods for routine verification of the performance of AE equipment comprising one or more sensing channels. It is intended for use by operators of the equipment under laboratory conditions. Verification of the measurement characteristics is recommended after purchase of equipment, modifications, use under extraordinary conditions, or if one suspects a malfunction. The procedures described in this European Standard do not exclude other qualified methods, e.g. verification in the frequency domain.

This European standard is concerned only with terms used specifically in acoustic emission testing (AT) and these fall into four parts:
-   Terms relating to the physical phenomenon;
-   Terms relating to the detection of the acoustic emission;
-   Terms relating to the measured acoustic emission signal(s);
-   Terms relating to acoustic emission applications.

This European Standard specifies the method for conducting acoustic emission (AE) + testing of metallic pressure equipment during acceptance pressure testing using a planar location method. General principles of acoustic emissions are described in EN 13554.
The objectives of the AE testing are to provide 100 % volumetric testing to define regions of the structure, which are acoustically active with burst type AE e.g. as a result of sub-critical flaw evolution; thus increasing the reliability of the acceptance test. The test provides a reference map for comparison with results of future tests.

This standard defines the general principles required for the acoustic emission (AE) testing of industrial structures, components, and different materials under stress and for harsh environment, in order to provide a defined and repeatable performance. It includes guide lines for the preparation of application documents, which describe the specific requirements for the application of the AE method.
Unless otherwise specified in the referencing documents, the minimum requirements of this standard are applicable.

This part of the standard specifies methods for routine verification of the performance of an AE equipment comprising one or more sensing channels. It is intended for use by operators of the equipment. Verification of the measurement characteristics is recommended after purchase of equipment, modifications or use under extraordinary conditions.

This standard is concerned only with terms used specifically in acoustic emission testing (AT) and these fall into four parts: - terms relating to the physical phenomenon; - terms relating to the detection of the signal(s); - terms relating to the measured characteristics of the signal(s); - terms relating to acoustic emission applications.