SIST EN 16407-2:2014
(Main)Non-destructive testing - Radiographic inspection of corrosion and deposits in pipes by X- and gamma rays - Part 2: Double Wall radiographic inspection
Non-destructive testing - Radiographic inspection of corrosion and deposits in pipes by X- and gamma rays - Part 2: Double Wall radiographic inspection
EN 16407-2 specifies fundamental techniques of film and digital radiography with the object of enabling satisfactory and repeatable results to be obtained economically. The techniques are based on generally recognized practice and fundamental theory of the subject. This European Standard applies to the radiographic examination of pipes in metallic materials for service induced flaws such as corrosion pitting, generalized corrosion and erosion. Besides its conventional meaning, “pipe” as used in this standard should be understood to cover other cylindrical bodies such as tubes, penstocks, boiler drums and pressure vessels. Weld inspection for typical welding process induced flaws is not covered, but weld inspection is included for corrosion/erosion type flaws. The pipes may be insulated or not, and can be assessed where loss of material due, for example, to corrosion or erosion is suspected either internally or externally. This part of EN 16407 covers double wall inspection techniques for detection of wall loss, including double wall single image (DWSI) and double wall double image (DWDI). Note that the DWDI technique described in this part of EN 16407 is often combined with the tangential technique covered in EN 16407-1. This European Standard applies to in-service double wall radiographic inspection using industrial radiographic film techniques, computed digital radiography (CR) and digital detector arrays (DDA).
Zerstörungsfreie Prüfung - Durchstrahlungsprüfung auf Korrosion und Ablagerungen in Rohren mit Röntgen- und Gammastrahlen - Teil 2: Doppelwand Durchstrahlungsprüfung
In diesem Teil werden grundlegende Techniken für die Durchstrahlungsprüfung unter Anwendung von Filmen und digitalen Techniken mit dem Ziel festgelegt, auf wirtschaftliche Art und Weise zuverlässige und wieder-holbare Ergebnisse zu erreichen. Die Techniken basieren sowohl auf den allgemein anerkannten praktischen Verfahren und den theoretischen Grundlagen dieses Fachbereichs.
Diese Norm gilt für die Durchstrahlungsprüfung von Rohren aus metallischen Werkstoffen zum Nachweis von Werkstofffehlern, die beim Gebrauch auftreten, z. B. Korrosionsmulden oder Fehler durch allgemeine Korrosi-on und Erosion. Neben der konventionellen Bedeutung sollten in dieser Norm unter der Benennung „Rohr“ (engl. pipe) auch andere zylindrische Gegenstände, z. B. Röhren/Schläuche, Druckrohrleitungen, Kessel-trommeln und Druckbehälter verstanden werden.
In dieser Norm nicht behandelt wird die Überprüfung von Schweißnähten auf die Fehler, die durch die herkömmlichen Schweißverfahren eingebracht werden; behandelt wird dagegen die Prüfung von Schweißver-bindungen zum Nachweis von Fehlern durch Korrosion/Erosion.
Die Prüfung kann an Rohren mit oder ohne Dämmung durchgeführt werden, beispielsweise in den Fällen, in denen vermutet wird, dass durch Korrosion oder Erosion ein Materialverlust an der Innen oder Mantelfläche des Rohrs entstanden ist.
Dieser Teil der vorliegenden Norm behandelt Doppelwand Durchstrahlungstechniken zum Nachweis einer Verringerung der Dicke der Rohrwand unter Einbeziehung von Doppelwand Einzelbild (DWSI) und Doppel-wand Doppelbild Techniken (DWDI).
Es ist zu beachten, dass die in diesem Teil 2 beschriebene Doppelwand-Doppelbild Technik (DWDI) häufig mit der tangentialen Durchstrahlung kombiniert wird, die in Teil 1 dieser Norm behandelt wird.
Diese Norm gilt für die Doppelwand Durchstrahlungsprüfung unter Anwendung der industriellen Röntgenfilm-techniken, der computerunterstützten digitalen Radiographie (CR) und der digitalen Matrixdetektoren (DDA).
Für die in dieser Norm beschriebenen grundlegenden Techniken sollte eine Nachweiswahrscheinlichkeit für durch Korrosion verursachte Fehler gegeben sein, die im Allgemeinen 5 % der Rohrwanddicke betreffen, sofern sie am Rohrumfang und in Richtung der Rohrlängsachse eine Mindestausdehnung von etwa 10 mm haben.
Essais non destructifs - Examen radiographique de la corrosion et des dépôts dans les canalisations, par rayons X et rayons gamma - Partie 2 : Examen radiographique double paroi
La présente Norme européenne spécifie les techniques fondamentales de radiographie sur film et de radiographie numérique permettant d'obtenir des résultats satisfaisants et reproductibles de manière économique. Les techniques reposent sur une pratique généralement reconnue et sur la théorie fondamentale en la matière.
La présente Norme européenne s'applique à l'examen radiographique des canalisations en matériaux métalliques afin de détecter des défauts induits par le service tels que piqûres de corrosion, corrosion généralisée et érosion. Outre sa signification conventionnelle, il convient de comprendre que le terme « canalisation », tel qu'il est utilisé dans la présente norme, couvre d'autres corps cylindriques tels que les tubes, les conduites forcées, les corps de chaudière et les récipients sous pression.
Le contrôle des soudures pour détecter les défauts types induits par le procédé de soudage n'est pas traité, mais un contrôle des soudures est inclus pour rechercher les défauts de type corrosion/érosion.
Les canalisations peuvent être isolées ou non et peuvent être évaluées lorsqu'une perte de matériau due, par exemple, à la corrosion ou à l'érosion, interne ou externe, est suspectée.
La présente partie de l'EN 16407 traite des techniques d'examen des doubles parois permettant la détection d'une perte de paroi, comprenant la technique double paroi simple image (DWSI) et la technique double paroi double image (DWDI).
Noter que la technique DWDI décrite dans la présente partie de l’EN 16407 est souvent combinée à la technique tangentielle traitée dans l’EN 16407-1.
La présente Norme européenne s'applique à l'examen radiographique des doubles parois en service en utilisant des techniques industrielles sur film radiographique, la radiographie numérisée (CR) et des mosaïques de détecteurs numériques (DDA).
Neporušitvene preiskave - Radiografski pregled korozije in nanosov v ceveh z rentgenskimi in gama žarki - 2. del: Radiografski pregled preko dveh sten
Standard EN 16407-2 določa temeljne tehnike filmske in digitalne radiografije z namenom omogočanja zadovoljivih in ponovljivih rezultatov, ki so stroškovno ugodni. Tehnike so osnovane na splošno priznani praksi in temeljnem poznavanju subjekta. Ta evropski standard velja za radiografski pregled cevi in kovinskih materialov za poškodbe, ki so posledica uporabe, kot na primer jamičasta korozija, splošna korozija in erozija. Poleg svojega klasičnega pomena izraz »cev«, kot je uporabljen v tem standardu, zajema tudi druga cilindrična telesa, kot so dovodni kanali, bobni kotlov in tlačne posode. Standard ne zajema pregleda zvarov za običajne napake, ki so posledica varilnega postopka, vključuje pa pregled zvarov za napake, ki so posledica korozije/erozije. Cevi so lahko izolirane ali ne in se jih lahko pregleda, če se sumi na notranjo ali zunanjo poškodbo materiala, ki je posledica korozije ali erozije. Ta del standarda EN 16407 zajema tehnike pregleda prek dveh sten za ugotavljanje poškodb na steni, vključno z enoslikovno tehniko prek dveh sten (DWSI) in dvoslikovno tehniko prek dveh sten (DWDI). Tehnika DWDI, opisana v tem delu standarda EN 16407 se pogosto uporablja skupaj s tangencialno tehniko, ki jo zajema standard EN 16407-1. Ta evropski standard velja za radiografski pregled prek dveh sten med obratovanjem, ki uporablja tehnike industrijskega radiografskega filma, računalniško digitalno radiografijo (CR) ali radiografijo z digitalnimi detektorskimi nizi (DDA).
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Neporušitvene preiskave - Radiografski pregled korozije in nanosov v ceveh z rentgenskimi in gama žarki - 2. del: Radiografski pregled preko dveh stenZerstörungsfreie Prüfung - Durchstrahlungsprüfung auf Korrosion und Ablagerungen in Rohren mit Röntgen- und Gammastrahlen - Teil 2: Doppelwand DurchstrahlungsprüfungEssais non destructifs - Examen radiographique de la corrosion et des dépôts dans les canalisations, par rayons X et rayons gamma - Partie 2 : Examen radiographique double paroiNon-destructive testing - Radiographic inspection of corrosion and deposits in pipes by X- and gamma rays - Part 2: Double Wall radiographic inspection23.040.01Deli cevovodov in cevovodi na splošnoPipeline components and pipelines in general19.100Neporušitveno preskušanjeNon-destructive testingICS:Ta slovenski standard je istoveten z:EN 16407-2:2014SIST EN 16407-2:2014en,fr,de01-julij-2014SIST EN 16407-2:2014SLOVENSKI
STANDARD
SIST EN 16407-2:2014
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 16407-2
January 2014 ICS 19.100; 23.040.01 English Version
Non-destructive testing - Radiographic inspection of corrosion and deposits in pipes by X- and gamma rays - Part 2: Double wall radiographic inspection
Essais non destructifs - Examen radiographique de la corrosion et des dépôts dans les canalisations, par rayons X et rayons gamma - Partie 2: Examen radiographique double paroi
Zerstörungsfreie Prüfung - Durchstrahlungsprüfung auf Korrosion und Ablagerungen in Rohren mit Röntgen- und Gammastrahlen - Teil 2: Doppelwand Durchstrahlungsprüfung This European Standard was approved by CEN on 26 October 2013.
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. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.
This European Standard exists 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-CENELEC Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,
B-1000 Brussels © 2014 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16407-2:2014 ESIST EN 16407-2:2014
EN 16407-2:2014 (E) 2 Contents Page Foreword .4 1 Scope .5 2 Normative references .5 3 Terms and definitions .6 4 Classification of radiographic techniques .8 5 General .9 5.1 Protection against ionizing radiation.9 5.2 Personnel qualification .9 5.3 Identification of radiographs .9 5.4 Marking .9 5.5 Overlap of films or digital images .9 5.6 Types and positions of image quality indicators (IQI) .9 5.6.1 Single wire IQI .9 5.6.2 Duplex wire IQI (digital radiographs) . 10 6 Recommended techniques for making radiographs . 10 6.1 Test arrangements . 10 6.1.1 General . 10 6.1.2 Double wall single image (DWSI) . 10 6.1.3 Double wall double image (DWDI) . 12 6.1.4 Alignment of beam and film/detector . 14 6.2 Choice of radiation source . 14 6.3 Film systems and screens . 15 6.4 Screens and shielding for imaging plates (computed radiography only) . 17 6.5 Reduction of scattered radiation . 18 6.5.1 Filters and collimators . 18 6.5.2 Interception of back scattered radiation . 19 6.6 Source-to-detector distance . 19 6.6.1 Double wall single image . 19 6.6.2 Double wall double image . 20 6.7 Axial coverage and overlap . 20 6.8 Circumference coverage . 21 6.8.1 General . 21 6.8.2 DWSI . 21 6.8.3 DWDI . 22 6.9 Selection of digital radiographic equipment . 22 6.9.1 General . 22 6.9.2 CR systems . 22 6.9.3 DDA systems . 22 7 Radiograph/digital image sensitivity, quality and evaluation . 22 7.1 Minimum image quality values . 22 7.1.1 Wire image quality indicators . 22 7.1.2 Duplex wire IQIs (digital radiographs) . 23 7.1.3 Minimum normalized signal to noise ratio (digital radiographs) . 23 7.2 Density of film radiographs . 23 7.3 Film processing . 24 7.4 Film viewing conditions . 24 SIST EN 16407-2:2014
EN 16407-2:2014 (E) 3 8 Measurement of differences in penetrated thickness . 24 8.1 Principle of technique . 24 8.2 Measurement of attenuation coefficient . 25 8.3 Source and detector positioning . 25 8.4 Image grey level profiles. 25 8.5 Validation. 25 8.6 Key Points . 25 9 Digital image recording, storage, processing and viewing . 26 9.1 Scan and read out of image. 26 9.2 Calibration of DDAs . 26 9.3 Bad pixel interpolation . 26 9.4 Image processing . 26 9.5 Digital image recording and storage . 26 9.6 Monitor viewing conditions . 27 10 Test report . 27 Annex A (normative)
Minimum image quality values . 29 Annex B (informative)
Penetrated thickness measurements from image grey levels . 31 Annex C (normative)
Determination of basic spatial resolution . 33 Bibliography . 36
SIST EN 16407-2:2014
EN 16407-2:2014 (E) 4 Foreword This document (EN 16407-2:2014) has been prepared by Technical Committee CEN/TC 138 “Non-destructive testing”, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by July 2014, and conflicting national standards shall be withdrawn at the latest by July 2014. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. EN 16407 consists of the following parts, under the general title Non-destructive testing — Radiographic inspection of corrosion and deposits in pipes by X- and gamma rays: — Part 1: Tangential radiographic inspection; — Part 2: Double wall radiographic inspection. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. SIST EN 16407-2:2014
EN 16407-2:2014 (E) 5 1 Scope This European Standard specifies fundamental techniques of film and digital radiography with the object of enabling satisfactory and repeatable results to be obtained economically. The techniques are based on generally recognized practice and fundamental theory of the subject. This European Standard applies to the radiographic examination of pipes in metallic materials for service induced flaws such as corrosion pitting, generalized corrosion and erosion. Besides its conventional meaning, “pipe” as used in this standard should be understood to cover other cylindrical bodies such as tubes, penstocks, boiler drums and pressure vessels. Weld inspection for typical welding process induced flaws is not covered, but weld inspection is included for corrosion/erosion type flaws. The pipes may be insulated or not, and can be assessed where loss of material due, for example, to corrosion or erosion is suspected either internally or externally. This part of EN 16407 covers double wall inspection techniques for detection of wall loss, including double wall single image (DWSI) and double wall double image (DWDI). Note that the DWDI technique described in this part of EN 16407 is often combined with the tangential technique covered in EN 16407-1. This European Standard applies to in-service double wall radiographic inspection using industrial radiographic film techniques, computed digital radiography (CR) and digital detector arrays (DDA). 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 14784-1, Non-destructive testing — Industrial computed radiography with storage phosphor imaging plates — Part 1: Classification of systems EN ISO 11699-1, Non-destructive testing — Industrial radiographic films — Part 1: Classification of film systems for industrial radiography (ISO 11699-1) EN ISO 11699-2, Non-destructive testing — Industrial radiographic films — Part 2: Control of film processing by means of reference values (ISO 11699-2) EN ISO 17636-2:2013, Non-destructive testing of welds — Radiographic testing — Part 2: X- and gamma-ray techniques with digital detectors (ISO 17636-2:2013) EN ISO 19232-1, Non-destructive testing — Image quality of radiographs — Part 1: Determination of the image quality value using wire-type image quality indicators (ISO 19232-1) EN ISO 19232-5, Non-destructive testing — Image quality of radiographs — Part 5: Determination of the image unsharpness value using duplex wire-type image quality indicators (ISO 19232-5) SIST EN 16407-2:2014
EN 16407-2:2014 (E) 6 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 basic spatial resolution of a digital detector SRbdetector half of the measured detector unsharpness in a digital image which corresponds to the effective pixel size and indicates the smallest geometrical detail, which can be resolved with a digital detector at magnification equal to one Note 1 to entry: For this measurement, the duplex wire IQI is placed directly on the digital detector array or imaging plate. Note 2 to entry: The measurement of unsharpness is described in EN ISO 19232-5, see also ASTM E2736 [18] and ASTM E1000 [16]. 3.2 computed radiography CR storage phosphor imaging plate system complete system comprising a storage phosphor imaging plate (IP) and a corresponding read-out unit (scanner or reader), which converts the information from the IP into a digital image 3.3 detector D radiographic image detector consisting of a NDT film system (see EN ISO 11699-1) or a digital radiography system using an imaging plate system (CR system) or a DDA system Note 1 to entry: Film systems and IPs can be used as flexible and curved detectors or in planar cassettes. 3.4 digital detector array system DDA system electronic device converting ionizing or penetrating radiation into a discrete array of analogue signals which are subsequently digitized and transferred to a computer for display as a digital image corresponding to the radiologic energy pattern imparted upon the input region of the device 3.5 DWDI double wall double image technique technique where the radiation source is located outside the pipe and away from the pipe, with the detector on the opposite side of the pipe and where the radiograph shows details from both the pipe walls on the detector and source sides of the pipe Note 1 to entry: See Figure 3. 3.6 DWSI double wall single image technique technique where the radiation source is located outside the pipe close to the pipe wall, with the detector on the opposite side of the pipe and where the radiograph shows only detail from the pipe wall on the detector side Note 1 to entry: See Figure 1. SIST EN 16407-2:2014
EN 16407-2:2014 (E) 7 3.7 nominal wall thickness t thickness of the pipe material only where manufacturing tolerances do not have to be taken into account 3.8 normalized signal-to-noise ratio SNRN signal-to-noise ratio, SNR, normalized by the basic spatial resolution, SRb, as measured directly in the digital image and/or calculated from the measured SNR, SNRmeasured, by: Nmeasuredb88,6µmSNR=SNRSR 3.9 object-to-detector distance b distance between the radiation side of the test object and the detector surface measured along the central axis of the radiation beam 3.10 outside diameter De nominal outside diameter of the pipe 3.11 penetrated thickness w thickness of material in the direction of the radiation beam calculated on the basis of the nominal thickness Note 1 to entry: For double wall radiographic inspection of a pipe, the minimum value for w is twice the pipe wall thickness. For multiple wall techniques, the penetrated thickness is calculated from the nominal wall thickness t. 3.12 pipe centre to detector distance PDD distance between the pipe centre and the detector 3.13 pixel size geometrical centre-to-centre distance between adjacent pixels in a row (horizontal pitch) or column (vertical pitch) of the scanned image [SOURCE: EN 14096-2:2003, 3.2] 3.14 signal-to-noise ratio SNR ratio of mean value of the linearized grey values to the standard deviation of the linearized grey values (noise) in a given region of interest in a digital image 3.15 source size d size of the radiation source [SOURCE: EN 12679:1999, 2.1] SIST EN 16407-2:2014
EN 16407-2:2014 (E) 8 3.16 source-to-detector distance SDD distance between the source of radiation and the detector measured in the direction of the beam 3.17 source-to-object distance f distance between the source of radiation and the source side of the test object measured along the central axis of the radiation beam 3.18 source-to-pipe centre distance SPD distance between the source of radiation and the pipe centre (pipe axis) measured in the direction of the beam 3.19 storage phosphor imaging plate IP photostimulable luminescent material capable of storing a latent radiographic image of a material being examined and, upon stimulation by a source of red light of appropriate wavelength, generates luminescence proportional to radiation absorbed 3.20 total effective penetrated thickness wtot total equivalent thickness of metallic material in the direction of the radiation beam calculated on the basis of the nominal thickness, with allowance for any liquid or other material present in the pipe and any insulation 4 Classification of radiographic techniques The double wall radiographic techniques are divided into two classes: — basic techniques DWA; — improved techniques DWB. The basic techniques are intended for double wall radiography of generalized and localized wall loss. For the basic techniques, DWA, when using Ir 192 sources for pipes with penetrated thicknesses between 15 mm and 35 mm, the sensitivity for detection will be high for imperfections, provided their diameters are ≥ 2 mm and the material loss is typically ≥ 5 % of the pipe penetrated thickness, in the absence of liquid or other products in the pipe. When using Se 75, the corresponding detection sensitivity will be high for 2 mm diameter or larger imperfections with material loss ≥ 4 % of the pipe penetrated thickness. The detection sensitivity will be improved for flaws with larger diameters, whereas the presence of liquid or other products, and external insulation, may reduce the sensitivity for material loss depending on their properties. Different detection sensitivities may apply for penetrated thicknesses < 15 mm and > 35 mm. These techniques can also be used for detection of deposits inside the pipe. The improved techniques should be used where higher sensitivity is required such as for radiography of fine, localized corrosion pitting. Further improvements, beyond the improved techniques described herein, are possible and may be agreed between the contracting parties by specification of all appropriate test parameters. SIST EN 16407-2:2014
EN 16407-2:2014 (E) 9 The choice of radiographic technique shall be agreed between the concerned parties. 5 General 5.1 Protection against ionizing radiation WARNING — Exposure of any part of the human body to X-rays or gamma-rays can be highly injurious to health. Wherever X-ray equipment or radioactive sources are in use, appropriate legal requirements shall be applied. Local or national or international safety precautions when using ionising radiation shall be strictly applied. 5.2 Personnel qualification Testing shall be carried out by proficient, suitably trained and qualified personnel and, where applicable, shall be supervised by competent personnel nominated by the employer or, by delegation of the employer, the inspection company in charge of testing. To demonstrate appropriate qualification it is recommended that personnel be certified according to EN ISO 9712 or an equivalent formalized system. Operating authorization for qualified persons shall be issued by the employer in accordance with a written procedure. NDT operations, unless otherwise agreed, shall be authorized by a competent and qualified NDT supervisory individual (Level 3 or equivalent) approved by the employer. The personnel shall prove additional training and qualification in digital industrial radiology if digital detectors are being used. 5.3 Identification of radiographs Symbols shall be affixed to each section of the object being radiographed. The images of these symbols shall appear in the radiograph outside the region of interest where possible and shall ensure unambiguous identification of the section. 5.4 Marking Permanent markings on the object to be examined should be made in order to accurately locate the position of each radiograph. Where the nature of the material and/or its service conditions do not permit permanent marking, the location may be recorded by means of accurate sketches. 5.5 Overlap of films or digital images When radiographing an area with two or more films or separate detectors, the films or detectors shall overlap sufficiently to ensure that the complete region of interest is radiographed. This shall be verified by a high density marker on the surface of the object which will appear on each film or detector. If the radiographs will be taken sequentially, the high density marker shall be visible on each of the radiographs. 5.6 Types and positions of image quality indicators (IQI) 5.6.1 Single wire IQI The quality of image shall be verified by use of IQIs in accordance with EN ISO 19232-1. For DWDI, the single wire IQI used shall be placed preferably on the source side of the test object at the centre of the area of interest. The IQI shall be in close contact with the surface of the object. If the IQIs cannot SIST EN 16407-2:2014
EN 16407-2:2014 (E) 10 be placed in accordance with the above conditions (insulated pipes), the IQIs will be placed on the detector side and the image quality shall be determined at least once from a comparison exposure with one IQI placed at the source side and one at the detector side under the same conditions. For DWSI, the single wire IQI used shall be placed on the detector side of the test object at the centre of the area of interest. If possible, the IQI shall be in close contact with the surface of the object. However, if this is not possible due for example to the presence of insulation, the IQI shall be in contact with the film/detector. For both DWDI and DWSI, the wire IQIs shall be aligned across the pipe, with their long axis angled at a few degrees (2° to 5°) to the orthogonal to the pipe axis. The IQI location should be in a section of uniform thickness, near to the pipe centre line. For DWDI, where the IQI's are placed at the detector side, the letter “F” shall be placed near the IQI and it shall be noted in the test report. The extent of image quality verification for repeat exposures of closely similar objects under identical conditions shall be subject to agreement between the contracting parties. 5.6.2 Duplex wire IQI (digital radiographs) IQIs in accordance with EN ISO 19232-5 should be used for measurement of the basic spatial resolution of the CR/DDA system in a reference radiograph (see 7.1.2 and Annex C). The duplex wire IQI shall be placed adjacent to the imaging plate or detector array and positioned a few degrees tilted (2° to 5°) to the digital rows or columns of the digital image. 6 Recommended techniques for making radiographs 6.1 Test arrangements 6.1.1 General Normally radiographic techniques in accordance with 6.1.2 and 6.1.3 shall be used. Technique 6.1.2 is normally used for larger diameter pipes. Technique 6.1.3 is generally used for smaller diameter pipes (less than typically about 150 mm outside diameter). For both techniques, the film or digital detector shall be placed as close to the pipe as possible. 6.1.2 Double wall single image (DWSI) For this arrangement with curved detectors or film, the source is located near to the pipe and with the film/detector on the opposite side, as shown in Figure 1 a) (without insulation) and Figure 1 b) (with insulation). The relevant distances for determination of source to detector distance, SDD (see 6.6), are also shown. SIST EN 16407-2:2014
EN 16407-2:2014 (E) 11
a) Non insulated pipe
b) Insulated pipe Key 1 detector Figure 1 — Test arrangement for double wall single image radiography (DWSI) using a curved detector Note that the wall loss can be located on either the inner diameter, outer diameter or both surfaces of the pipe wall adjacent to the detector. Wall loss on the source side of the pipe is not imaged. For rigid planar detectors, DWSI can also be applied as shown in Figure 2a) and Figure 2 b), although with this arrangement a smaller fraction of the pipe circumference can be inspected at each position.
SIST EN 16407-2:2014
EN 16407-2:2014 (E) 12
a) Non insulated pipe
b) insulated pipe Key 1 detector Figure 2 — Test arrangement for double wall single image radiography (DWSI) using a planar detector 6.1.3 Double wall double image (DWDI) For this arrangement, the radiation source is located in front of the pipe and with the planar film/detector at the opposite side, as shown in Figure 3a) (non insulated pipe) and Figure 3b) (insulated pipe).
SIST EN 16407-2:2014
EN 16407-2:2014 (E) 13
a) Non insulated pipe
b) Insulated pipe Key 1 detector Figure 3 — Test arrangement for double wall double image radiography (DWDI) With DWDI, the wall loss can be located on either the inner diameter, outer diameter or both surfaces of the pipe, and on either the source or detector side of the pipe. If DWDI and tangential radiographic tech
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SLOVENSKI STANDARD
oSIST prEN 16407-2:2012
01-junij-2012
Neporušitveno preskušanje - Radiografski pregled korozije in nanosov v ceveh z
rentgenskimi in gama žarki - 2. del: Double Wall radiografski pregled
Non-destructive testing - Radiographic inspection of corrosion and deposits in pipes by X
- and gamma rays - Part 2: Double Wall radiographic inspection
Zerstörungsfreie Prüfung - Durchstrahlungsprüfung auf Korrosion und Ablagerungen in
Rohren mit Röntgen- und Gammastrahlen - Teil 2: Doppelwand Durchstrahlungsprüfung
Ta slovenski standard je istoveten z: prEN 16407-2
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
23.040.01 Deli cevovodov in cevovodi Pipeline components and
na splošno pipelines in general
oSIST prEN 16407-2:2012 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN 16407-2:2012
EUROPEAN STANDARD
DRAFT
prEN 16407-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2012
ICS
English Version
Non-destructive testing - Radiographic inspection of corrosion
and deposits in pipes by X- and gamma rays - Part 2: Tangential
radiographic inspection
Zerstörungsfreie Prüfung - Durchstrahlungsprüfung auf
Korrosion und Ablagerungen in Rohren mit Röntgen- und
Gammastrahlen - Teil 2: Doppelwand
Durchstrahlungsprüfung
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-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, 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, Turkey 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
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 16407-2:2012: E
worldwide for CEN national Members.
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Contents Page
Foreword .4
1 Scope .5
2 Normative references .5
3 Terms and definitions .6
4 Classification of radiographic techniques .7
5 General .8
5.1 Protection against ionizing radiation.8
5.2 Personnel qualification .8
5.3 Surface preparation .8
5.4 Identification of radiographs .8
5.5 Marking .8
5.6 Overlap of films or digital images .8
5.7 Types and positions of image quality indicators (IQI) .9
5.7.1 Single wire IQI .9
5.7.2 Duplex wire IQI (digital radiographs) .9
6 Recommended techniques for making radiographs .9
6.1 Test arrangements .9
6.1.1 General .9
6.1.2 Double wall single image (DWSI) .9
6.1.3 Double wall double image (DWDI) . 11
6.1.4 Alignment of beam and film/detector . 13
6.2 Choice of radiation source . 13
6.3 Film systems and screens . 14
6.4 Screens and shielding for imaging plates (computed radiography only) . 16
6.5 Reduction of scattered radiation . 18
6.5.1 Filters and collimators . 18
6.5.2 Interception of back scattered radiation . 18
6.6 Source-to-detector distance . 19
6.6.1 Double wall single image . 19
6.6.2 Double wall double image . 19
6.7 Axial coverage and overlap . 19
6.8 Circumference coverage . 20
6.8.1 DWSI . 20
6.8.2 DWDI . 21
6.9 Operation of computed radiography equipment . 21
7 Radiograph/digital image sensitivity, quality and evaluation . 22
7.1 Minimum image quality values . 22
7.1.1 Wire image quality indicators . 22
7.1.2 Duplex wire IQIs (digital radiographs) . 22
7.1.3 Minimum normalised signal to noise ratio (digital radiographs) . 22
7.2 Density of film radiographs . 23
7.3 Film processing . 23
7.4 Film viewing conditions . 23
8 Measurement of differences in penetrated thickness . 23
8.1 Principle of technique . 23
8.2 Measurement of attenuation coefficient . 24
8.3 Source and detector positioning . 24
8.4 Image grey level profiles . 24
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8.5 Validation. 24
8.6 Key Points . 24
9 Digital Image recording, storage, processing and viewing . 25
9.1 Digital image recording and storage . 25
9.2 Image processing for digital radiographs . 25
9.3 Monitor viewing conditions . 25
10 Test report . 26
Annex A (normative) Minimum image quality values . 28
Annex B (informative) Penetrated thickness measurements : Image grey level profiles. 30
Bibliography . 32
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Foreword
This document (prEN 16407-2:2012) 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.
prEN 16407 consists of the following parts, under the general title Non-destructive testing — Radiographic
inspection of corrosion and deposits in pipes by X- and gamma rays :
— Part 1: Tangential radiographic inspection
— Part 2: Double Wall radiographic inspection
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1 Scope
This part specifies fundamental techniques of film and digital radiography with the object of enabling
satisfactory and repeatable results to be obtained economically. The techniques are based on generally
recognized practice and fundamental theory of the subject.
This standard applies to the radiographic examination of pipes in metallic materials for service induced flaws
such as corrosion pitting, generalised corrosion and erosion. Besides its conventional meaning, "pipe" as used
in this standard should be understood to cover other cylindrical bodies such as tubes, penstocks, boiler drums
and pressure vessels.
Weld inspection for typical welding process induced flaws is not covered, but weld inspection is included for
corrosion/erosion type flaws.
The pipes may be insulated or not, and can be assessed where loss of material due, for example, to corrosion
or erosion is suspected either internally or externally.
This Part of this standard covers double wall inspection techniques for detection of wall loss, including double
wall single image (DWSI) and double wall double image (DWDI).
Note that the DWDI technique described in this Part 2, is often combined with the tangential technique
covered in Part 1 of this standard.
This standard applies to in-service double wall radiographic inspection using industrial radiographic film
techniques, computed digital radiography (CR) and digital detector arrays (DDA).
For the basic techniques described in this standard, the probability of detection should be high for corrosion
type flaws with through wall extents of typically ≥ 5% of the pipe wall thickness, provided the circumferential
and axial extents of the flaws are about 10mm or larger.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
EN 12679:1999, Non-destructive testing — Determination of the size of industrial radiographic sources —
Radiographic method
EN 14096-2:2003, Non-destructive testing - Qualification of radiographic film digitisation systems - Part 2:
Minimum requirements
EN 14784-1, Non-destructive testing — Industrial computed radiography with storage phosphor imaging
plates — Part 1: Classification of systems
EN 25580:1992, Non-destructive testing - Industrial radiographic illuminators - Minimum requirements
prEN ISO 9712, Non-destructive testing — Qualification and certification of personnel
FprEN ISO 17636–2:2012, Non-destructive testing of welds — Radiographic examination of welded joints —
Part 2: X- and gamma-ray techniques with digital detectors
prEN ISO 19232–1:2011, Non-destructive testing — Image quality of radiographs — Part 1: Image quality
indicators (wire type) - Determination of image quality value
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prEN ISO 19232–2:2011, Non-destructive testing — Image quality of radiographs — Part 2: Image quality
indicators (step/hole type) — Determination of image quality value
prEN ISO 19232–4:2011, Non-destructive testing — Image quality of radiographs — Part 4: Experimental
evaluation of image quality values and image quality tables
prEN ISO 19232–5:2011, Non-destructive testing — Image quality of radiographs — Part 5: Image quality
indicators (duplex wire type) - Determination of image unsharpness value
EN ISO 11699-1, Non-destructive testing - Industrial radiographic film - Part 1: Classification of film systems
for industrial radiography
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
DWSI
double wall single image technique. The radiation source is located outside the pipe close to the pipe wall,
with the detector on the opposite side of the pipe. The radiograph shows only detail from the pipe wall on the
detector side. See Figure 1.
3.2
DWDI
double wall double image technique. The radiation source is located outside the pipe and away from the pipe,
with the detector on the opposite side of the pipe. The radiograph shows details from both the pipe walls on
the detector and source sides of the pipe. See Figure 2.
3.3
nominal thickness
t
nominal thickness of the parent material only where manufacturing tolerances do not have to be taken into
account
3.4
object-to-detector distance
b
distance between the radiation side of the test object and the detector surface measured along the central
axis of the radiation beam
3.5
outside diameter
D
e
nominal outside diameter of the pipe
3.6
penetrated thickness
w
thickness of material in the direction of the radiation beam calculated on the basis of the nominal thickness
Note 1 to entry: For double wall radiographic inspection of a pipe, the minimum value for w is twice the pipe wall
thickness. For multiple wall techniques the penetrated thickness is calculated from the nominal thickness.
3.7
pipe centre to detector distance
PDD
distance between the pipe centre and the detector
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3.8
source size
d
size of the radiation source
[SOURCE: EN 12679:1999, 2.1]
3.9
source-to-detector distance
SDD
distance between the source of radiation and the detector measured in the direction of the beam
3.10
source-to-pipe centre distance
SPD
distance between the source of radiation and the pipe centre (pipe axis) measured in the direction of the beam
3.11
source-to-object distance
f
distance between the source of radiation and the source side of the test object measured along the central
axis of the radiation beam
3.12
total effective penetrated thickness
W
tot
total equivalent thickness of metallic material in the direction of the radiation beam calculated on the basis of
the nominal thickness, with allowance for any liquid or gaseous product present in the pipe
3.13
pixel size
geometrical centre-to-centre distance between adjacent pixels in a row (horizontal pitch) or column (vertical
pitch) of the scanned image
[SOURCE: EN 14096-2:2003]
4 Classification of radiographic techniques
The double wall radiographic techniques are divided into two classes:
basic techniques DWA
improved techniques DWB
The Basic techniques are intended for double wall radiography of generalised and localised wall loss.
The Improved techniques should be used where higher sensitivity is required such as for radiography of fine,
localised corrosion pitting flaws.
Further improvements, beyond the Improved techniques described herein are possible and may be agreed
between the contracting parties by specification of all appropriate test parameters.
The choice of radiographic technique shall be agreed between the concerned parties.
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5 General
5.1 Protection against ionizing radiation
WARNING — Exposure of any part of the human body to X-rays or gamma-rays can be highly
injurious to health. Wherever X-ray equipment or radioactive sources are in use, appropriate legal
requirements must be applied. Local or national or international safety precautions when using
ionizing radiation shall be strictly applied.
5.2 Personnel qualification
Testing shall be carried out by proficient, suitably trained and qualified personnel and, where applicable, shall
be supervised by competent personnel nominated by the employer or, by delegation of the employer, the
inspection company in charge of testing. To demonstrate appropriate qualification it is recommended that
personnel be certified according to prEN ISO 9712 or an equivalent formalised system. Operating
authorisation for qualified person shall be issued by the employer in accordance with a written procedure.
NDT operations, unless otherwise agreed, shall be authorised by a competent and qualified NDT supervisory
individual (Level 3 or equivalent) approved by the employer.
The personnel shall prove additional training and qualification in digital industrial radiology if digital detectors
are being used.
5.3 Surface preparation
In general, surface preparation is not necessary, but where surface imperfections or coatings might cause
difficulty in detecting flaws or significant errors in thickness measurements, the surface shall be ground
smooth or the coatings shall be removed.
5.4 Identification of radiographs
Symbols shall be affixed to each section of the object being radiographed. The images of these symbols shall
appear in the radiograph outside the region of interest where possible and shall ensure unambiguous
identification of the section.
5.5 Marking
Permanent markings on the object to be examined shall be made in order to accurately locate the position of
each radiograph.
Where the nature of the material and/or its service conditions do not permit permanent marking, the location
may be recorded by means of accurate sketches.
5.6 Overlap of films or digital images
When radiographing an area with two or more films or separate detectors, the films or detectors shall overlap
sufficiently to ensure that the complete region of interest is radiographed. This shall be verified by a high
density marker on the surface of the object which will appear on each film or detector. If the radiographs will
be taken sequentially, the high density marker shall be visible on each of the radiographs.
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5.7 Types and positions of image quality indicators (IQI)
5.7.1 Single wire IQI
The quality of image shall be verified by use of IQIs in accordance with prEN ISO 19232-1:2011.
For DWDI, the single wire IQI used shall be placed preferably on the source side of the test object at the
centre of the area of interest. The IQI shall be in close contact with the surface of the object. If the IQIs cannot
be placed in accordance with the above conditions (insulated pipes), the IQIs will be placed on the detector
side and the image quality shall be determined at least once from a comparison exposure with one IQI placed
at the source side and one at the detector side under the same conditions.
For DWSI, the single wire IQI used shall be placed on the film/detector side of the test object at the centre of
the area of interest. If possible, the IQI shall be in close contact with the surface of the object. However, if this
is not possible due for example to the presence of insulation, the IQI shall be in contact with the film/detector.
For both DWDI and DWSI, the wire IQIs shall be aligned across the pipe, with their long axis angled at a few
degrees (2º - 5º) to the orthogonal to the pipe axis. The IQI location shall be in a section of uniform thickness,
near to the pipe centre line.
For DWDI, where the IQI's are placed at the detector side, the letter "F" shall be placed near the IQI and it
shall be noted in the test report.
The extent of image quality verification for repeat exposures of closely similar objects under identical
conditions shall be subject to agreement between the contracting parties.
5.7.2 Duplex wire IQI (digital radiographs)
IQIs in accordance with prEN ISO 19232-5:2011 should be used for measurement of the basic spatial
resolution of the CR/DR system (see 7.1.2), as applied to the radiography of the test object (same
scanner/imaging plate and user settings such as pixel size). The duplex wire IQI shall be positioned a few
degrees tilted (2º - 5°) to the digital rows or columns of the digital image.
6 Recommended techniques for making radiographs
6.1 Test arrangements
6.1.1 General
Normally radiographic techniques in accordance with 6.1.2 and 6.1.3 shall be used.
Technique 6.1.2 is normally used for larger diameter pipes. Technique 6.1.3 is generally used for smaller
diameter pipes (less than typically about 150 mm outside diameter).
For both techniques, the film or digital detector shall be placed as close to the pipe as possible.
6.1.2 Double wall single image (DWSI)
For this arrangement with curved detectors or film, the source is located near to the pipe and with the
film/detector on the opposite side, as shown in Figure 1a) (without insulation) and Figure 1b) (with insulation).
The relevant distances for determination of source to detector distance, SDD, (see 6.6) are also shown.
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a) non insulated pipe
b) insulated pipe
Key
1 detector
Figure 1 — Test arrangement for double wall single image radiography (DWSI) using a curved detector
Note that the wall loss can be located on either the inner diameter or outer diameter surface of the pipe wall
adjacent to the film/detector. Wall loss on the source side of the pipe is not imaged.
For rigid planar detectors, DWSI can also be applied as shown in Figure 2a) and Figure 2b), although with this
arrangement a smaller fraction of the pipe circumference can be inspected at each position.
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a) non insulated pipe
b) insulated pipe
Key
1 detector
Figure 2 — Test arrangement for double wall single image radiography (DWSI) using a planar detector
6.1.3 Double wall double image (DWDI)
For this arrangement, the radiation source is located in front of the pipe and with the planar film/detector at the
opposite side, as shown in Figure 3a) (non insulated pipe) and Figure 3b) (insulated pipe).
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a) non insulated pipe
b) insulated pipe
Key
1 detector
Figure 3 — Test arrangement for double wall double image radiography (DWDI)
With DWDI, the wall loss can be located on either the inner diameter or outer diameter surface of the pipe,
and on either the source or film/detector side of the pipe.
If DWDI and tangential radiographic techniques are combined the requirements of part 1 of this standard shall
be met also.
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6.1.4 Alignment of beam and film/detector
The beam of radiation shall be directed at the centre of the area being examined and should be perpendicular
to the pipe axis.
For DWDI, the film or detector should be aligned to be orthogonal to the centre of the radiation beam.
Modifications to these alignments and the test arrangements given in 6.1.2 and 6.1.3 may be needed in
special cases, due for example to the presence of obstructions.
Other ways of radiographing may be agreed between contracting parties.
6.2 Choice of radiation source
Penetrated thickness ranges for X-ray and gamma ray sources are given in Table 1 and Figure 4. By
agreement between contracting parties, these ranges can be extended.
The maximum X-ray voltages shown in Figure 4 are best practice values for film radiography of welds. If
DDAs with accurate calibration are used, sufficient image quality can still be obtained using higher X-ray
voltages than those shown in Figure 4.
In the cases where the radiographs are produced using gamma rays, the travel time to position the source
shall not exceed 10 % of the total exposure time.
Table 1 — Penetrated thickness ranges for gamma-ray sources for steel
Radiation source Penetrated thickness
w
mm
basic technique DWA improved technique
DWB
Yb 169
1 ≤ w ≤ 15 1 ≤ w ≤ 15
Se 75 5 ≤ w ≤ 55 10 ≤ w ≤ 40
Ir 192
7 ≤ w ≤ 85 20 ≤ w ≤ 70
Co 60
40 ≤ w ≤ 200
X-ray equipment with energy
30 ≤ w ≤ 200
from 1 MeV to 4 MeV
X-ray equipment with energy w ≥ 50
from 4 MeV to 12 MeV
X-ray equipment with energy w ≥ 80
above 12 MeV
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Key
1 copper/nickel and alloys
2 steel
3 titanium and alloys
4 aluminium and alloys
w penetrated thickness in mm
U X-ray voltage in kV
Figure 4 — Maximum X-ray voltage U for X-ray devices up to 1 000 kV as a function of penetrated
thickness w and material
For product filled pipes, the additional radiation attenuation caused by the product shall be allowed for in
selection of sources. For a product filled pipe, the penetrated thickness, w, in Table 1 and Figure 4 shall be
increased by approximately one ninth of the path length in the water, and by one eleventh of the path length in
oil.
6.3 Film systems and screens
For radiographic examination, film system classes shall be used in accordance with EN ISO 11699-1.
The radiographic film system class and metal screens for different radiation sources are given in Table 2.
When using metal screens, good contact between films and screens is required. This may be achieved either
by using vacuum-packed films or by applying pressure.
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