SIST EN 16016-4:2012

SLOVENSKI STANDARD
oSIST prEN 16016-4:2010
01-marec-2010
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Non destructive testing - Radiation Methods - Computed Tomography - Part 4:
Qualification
Zerstörungsfreie Prüfung - Durchstrahlungsverfahren - Teil 4: Qualifizierung
Essais non destructifs - Moyens utilisant les rayonnements - Tomographie informatisée -
Partie 4: Qualification
Ta slovenski standard je istoveten z: prEN 16016-4
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
oSIST prEN 16016-4:2010 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 16016-4:2010


EUROPEAN STANDARD
DRAFT
prEN 16016-4
NORME EUROPÉENNE

EUROPÄISCHE NORM

November 2009
ICS 19.100
English Version
Non destructive testing - Radiation Methods - Computed
Tomography - Part 4: Qualification
Essais non destructifs - Moyens utilisant les rayonnements Zerstörungsfreie Prüfung - Durchstrahlungsverfahren -
- Tomographie informatisée - Partie 4: Qualification Computertomography - Teil 4: Qualifizierung
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 138.

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language
made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the
same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.


EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 16016-4:2009: E
worldwide for CEN national Members.

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Contents Page
Foreword .3
Introduction .4
1 Scope .5
2 Normative references .5
3 Terms and definitions .5
4 Qualification of the inspection .5
4.1 General .5
4.2 Qualification of defect testing .5
4.2.1 Quality feature .5
4.2.2 Feature detectability/test system/system parameterisation .6
4.2.3 Verification of suitability .7
4.2.4 Consistency check .8
4.2.5 Documentation .8
4.3 Qualification of dimensional testing .8
4.3.1 Test and measurement task .8
4.3.2 Dimensional testing/test system/system parameterisation .8
4.3.3 Degree of accuracy .9
4.3.4 Consistency check . 10
4.3.5 Documentation . 10
5 Qualification of the CT system . 10
5.1 Integral overall system test . 10
5.2 Checking the system components . 10
5.2.1 Manipulation system . 10
5.2.2 Image scale . 11
5.2.3 Beam axis perpendicularity . 11
5.2.4 Tube focal spot . 11
5.2.5 Tube stability . 11
5.2.6 Detector . 11
5.2.7 Reconstruction . 11
5.2.8 Visualisation . 11
5.3 Documentation . 11
6 Example of CT system resolution evaluation methods . 11
6.1 Pre-amble . 11
6.2 Acquisition parameters . 12
6.3 Recommendations for creating reference objects . 12
6.4 Density resolution measurement method . 13
6.4.1 High energy reference object . 13
6.4.2 Low energy reference object . 14
6.4.3 Experimental measurements . 14

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Foreword
This document (prEN 16016-4:2009) has been prepared by Technical Committee CEN/TC 138 “Non-
destructive testing”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
This standard consists of the following parts, under the general title, Radiation methods – Computed
tomography :
 Part 1 : Terminology ;
 Part 2 : Principle, equipment and samples
 Part 3 : Operation and interpretation
 Part 4 : Qualification.
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Introduction
This document gives guidelines for the general principles of X-ray computed tomography (CT) applicable to
industrial imaging (in the context of this standard, industrial means non-medical applications); it also gives a
consistent set of CT performance parameter definitions, including how these performance parameters relate
to CT system specifications. This document deals with computed axial tomography and excludes other types
of tomography such as translational tomography and tomosynthesis.
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1 Scope
This part describes guidelines for the qualification of the performance of a CT system with respect to various
inspection tasks.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
prEN 16016-1, Non Destructive Testing – Radiation method – Computed tomography - Terminology.
prEN 16016-3, Non Destructive Testing – Radiation method – Computed tomography - Operation and
Interpretation.
3 Terms and definitions
For the purposes of this document, the terms and definitions given in prEN 16016-1 apply.
4 Qualification of the inspection
4.1 General
CT is used in industry both for defect testing and dimensional testing and measurement. Because CT does
not directly provide measurement of desired quantities like, for example, pore size or wall thickness, these
quantities must be derived from the X-ray linear attenuation data represented by the CT grey values. The
detectability of features and the degree of accuracy required depend on the inspection task, the specification
of the available test equipment and the analysis and evaluation methods used. When determination of the
such quantities is required, a special task-specific qualification test of the CT system is required. The
qualification measures are described in 4.2 and 4.3. The qualification should be carried out by trained
personnel.
4.2 Qualification of defect testing
Under test qualification, that the suitability of the proposed inspection technique for measuring a quantity to
the required precision should be verified. The following steps described are typical of those for the successful
verification of the suitability of CT for industrial applications.
4.2.1 Quality feature
Typical quantities to be measured are the sizes of pores, cavities, cracks, inclusions, contaminants as well as
studies of the material distribution and the assembly and installation position of components. Because the test
sample and the type, position and size of the features to be detected determine the properties of a CT system
to be used, information such as the following should be known:
a) test object :
 dimensions ;
 weight ;
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 materials ;
 path length to be X-rayed in the material.
b) test feature :
 type ;
 position ;
 size ;
 distribution, frequency.
c) feature detectability :
 limiting defect ;
 limiting feature.
Because the feature detectability strongly influences the specification and therefore the cost of a CT system,
special attention must be taken when defining the sensitivity of the tests required. If, due to missing
information, no limiting values for features are defined , it is recommended that you use the best possible
sensitivity for the specific method and CT system and verify the attained feature detectability using, for
example, destructive tests.
4.2.2 Feature detectability/test system/system parameterisation
The usability of the CT system and the selection of system parameters are determined by the requirements for
feature detectability. Typical variables are :
a) spatial resolution :
 image scale ;
 detector spatial resolution ;
 focal spot size of radiation source.
b) contrast resolution :
 detector dynamics ;
 attenuation difference (defect size relative to the overall wall thickness) ;
 tube voltage ;
 tube current ;
 exposure time.
c) Reconstruction / visualisation :
 number of projections ;
 CT grey value dynamics of the reconstruction or visualisation ;
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 CT image size in x, y and z .
CT system set-up and image quality parameters are described in 4.1 and 5.1 of prEN 16016-3.
4.2.3 Verification of suitability
A reliable statement on the defect detection sensitivity and the defect detectability of the CT system used in a
test shall be made, if necessary, by stating the degree of accuracy of the test required (tolerance, degree of
fluctuation). Several alternative procedures are described in the following.
4.2.3.1 Reference sample with a natural defect
If a reference sample with a known defect is available, inspection of this sample is carried out and the
detectability is stated after the test has been done.
If a reference sample with unquantified defects is available, inspection of this part is carried out and the defect
detectability is stated using a counter-check, using, for example, a destructive test after the CT scan has been
done. Typical specifications are:
a) test parameters
 tube type ;
 detector type ;
 voxel size, spatial resolution ;
 contrast resolution ;
 filtering ;
 voltage ;
 current ;
 CT image size in x, y and z.
b) defect detectability
 tested area ;
 limiting defect size.
4.2.3.2 Reference sample with synthetic defect
If the test feature can be simulated using a synthetic defect, for example, a bored hole, the defect detectability
verification can take place similar to the previous section.
4.2.3.3 Reference sample without specifications
If no specifications are available for the reference sample status and a counter-check is not possible, the test
is carried out using the system sensitivity. Sample structures like, for example, wall thicknesses and external
dimensional measurements can be used for estimating the defect detectability. Alternatively reference
samples like, for example, wires or spheres of known dimensions can be used.
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4.2.4 Consistency check
The CT test process requires several, in themselves very complex process steps, for which the error sources
can not always be excluded. After the test has been carried out, the following parameters can be provided
with possible errors stated:
 reconstruction: size, CT slice positions, possible artefacts ;
 image scale ;
 image unsharpness ;
 intensity jumps ;
 sinogram (CT grey value and curve progress) or CT projection sequence ;
 system status (error messages) ;
where test procedure errors are suspected, then where possible the error cause is to be eliminated and the
test is to be repeated.
...