CEN TR 17108-2017 Non-destructive testing - Lighting in penetrant and magnetic particle testing good practice.pdf

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1、Non-destructive testing - Lighting in penetrant and magnetic particle testing, good practicePD CEN/TS 17108:2017BSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06TECHNICAL REPORT RAPPORT TECHNIQUE TECHNISCHER BERICHT CEN/TR 17108 June 2017 ICS 19.100 English Version No

2、n-destructive testing - Lighting in penetrant and magnetic particle testing, good practice Essais non destructifs - Bonnes pratiques dclairage lors des contrles par ressuage et par magntoscopieZerstrungsfreie Prfung - Beleuchtung in Eindring- und Magnetpulverprfung, bewhrte Verfahren This Technical

3、Report was approved by CEN on 28 May 2017. It has been drawn up by the Technical Committee CEN/TC 138. 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, Gree

4、ce, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR

5、NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2017 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. CEN/TR 17108:2017 ENational forewordThis Published Document is the UK implementation of CEN/TS 17108:2017.Th

6、e UK participation in its preparation was entrusted to Technical Committee WEE/46, Non-destructive testing.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users

7、are responsible for its correct application. The British Standards Institution 2017 Published by BSI Standards Limited 2017ISBN 978 0 580 97009 2ICS 19.100Compliance with a British Standard cannot confer immunity from legal obligations.This Published Document was published under the authority of the

8、 Standards Policy and Strategy Committee on 30 September 2017.Amendments/corrigenda issued since publicationDate Text affectedPUBLISHED DOCUMENTPD CEN/TS 17108:2017TECHNICAL REPORT RAPPORT TECHNIQUE TECHNISCHER BERICHT CEN/TR 17108 June 2017 ICS 19.100 English Version Non-destructive testing - Light

9、ing in penetrant and magnetic particle testing, good practice Essais non destructifs - Bonnes pratiques dclairage lors des contrles par ressuage et par magntoscopieZerstrungsfreie Prfung - Beleuchtung in Eindring- und Magnetpulverprfung, bewhrte Verfahren This Technical Report was approved by CEN on

10、 28 May 2017. It has been drawn up by the Technical Committee CEN/TC 138. 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

11、, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Managemen

12、t Centre: Avenue Marnix 17, B-1000 Brussels 2017 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. CEN/TR 17108:2017 EPD CEN/TS 17108:2017CEN/TR 17108:2017 (E) 2 Contents Page European foreword . 3 1 Scope 4 2 Normative references 4 3 T

13、erms and definitions . 4 4 Fluorescent techniques, inspection booth, lights and visual ergonomics 5 4.1 Lights: UV-A beam spectral characteristics . 5 4.1.1 General 5 4.1.2 Symmetry of the spectrum around the centroid wavelength . 5 4.1.3 Unwanted visible light of the UV-A spectrum: limitation of th

14、e emission 380 nm 6 4.1.4 Radiometric specifications: UV-A/violet ratio . 6 4.1.5 Thermal management (cooling), sustaining performances 8 4.2 UV-A beam geometrical characteristics 9 4.2.1 General 9 4.2.2 Geometric consideration for use . 9 4.2.3 Large parts 10 4.2.4 Small parts 10 4.3 Identification

15、 and repair . 11 4.4 Health and safety when using UV-A sources 11 4.4.1 Precautions for use 11 4.4.2 Warning panels . 11 4.4.3 Eyewear . 13 4.5 Visual ergonomics 14 4.5.1 General . 14 4.5.2 Visual adaptation, general 14 4.5.3 Visible light before inspection . 15 4.5.4 Visible light during inspection

16、 16 4.5.5 Visible light after inspection: focus recovery/preserving 17 4.5.6 Transition zones: avoid visual tiredness . 18 4.5.7 General irradiance . 18 5 Colour and luminous contrast method . 18 5.1 White beam spectral characteristics . 18 5.2 Viewing of coloured materials: choosing the source. 19

17、5.3 Precautions for use 20 5.3.1 High-luminance type LED sources . 20 5.3.2 Eyewear . 22 5.4 Illuminance levels of the inspection area and of the surrounding area: visual ergonomics . 23 5.4.1 General . 23 5.4.2 Fixed inspection areas 23 5.4.3 On-site inspections 23 5.4.4 Case study . 23 6 Measureme

18、nts . 25 6.1 Radiometers and luxmeters characteristics/specifications 25 6.2 Irradiance measurement . 25 7 Actinic Blue . 26 PD CEN/TS 17108:2017CEN/TR 17108:2017 (E) 3 European foreword This document (CEN/TR 17108:2017) has been prepared by Technical Committee CEN/TC 138 “Non-destructive testing”,

19、the secretariat of which is held by AFNOR. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights. PD CEN/TS 17108:2017CEN/TR 17108:2017 (E) 4 1 Scope This T

20、echnical Report describes the good practices of lighting under UV-A radiation and in white light as used for penetrant testing (PT) and magnetic particle testing (MT) for improved probability of detection (POD). This informative document deals with the irradiance and the illuminance used in PT and M

21、T. It is intended for: manufacturers, who are encouraged to supply the criteria and the restrictions on use of their products, as well as detailed characteristics for the appropriate choice and the optimum use of sources available on the market; users, to enable them to make the best use of lighting

22、 sources for efficient inspection in working conditions; supervision and training personnel, who may design and optimally arrange inspection areas, recommend the principles of visual ergonomics for ensuring inspector efficiency, comfort and safety. 2 Normative references The following documents, in

23、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 170, Personal eye-protection Ult

24、raviolet filters Transmittance requirements and recommended use EN 12464-1, Light and lighting Lighting of work places Part 1: Indoor work places CEN/TR 16638, Non-destructive testing Penetrant and magnetic particle testing using blue light EN 62471, Photobiological safety of lamps and lamp systems

25、(IEC 62471) EN ISO 12706, Non-destructive testing Penetrant testing Vocabulary (ISO 12706) EN ISO 12707, Non-destructive testing Magnetic particle testing Vocabulary (ISO 12707) ISO/CIE 19476 (CIE S 023/E), Characterization of the performance of illuminance meters and luminance meters 3 Terms and de

26、finitions For the purpose of this document, the terms and definitions given in EN ISO 12706, EN ISO 12707 and the following apply. 3.1 centroid wavelength mathematically weighted mean output wavelength sharing in two equal parts the spectrum emitted by a source PD CEN/TS 17108:2017CEN/TR 17108:2017

27、(E) 5 3.2 colour rendering index CRI degree of agreement between the colour appearance of objects illuminated by the considered source and that of the same objects illuminated by a reference illuminant, under specified viewing conditions 3.3 colour temperature Tcp temperature of a planckian (or blac

28、k body) radiator, the radiation of which has the same chromaticity as a given stimulus, expressed in Kelvin (K) 3.4 LEDs light-emitting diodes 3.5 maculopathy impaired function of the macula which degrades colour vision and leads to a decrease of visual acuity 3.6 mesopic vision twilight or medium v

29、ision between the photopic vision and the scotopic vision 3.7 photopic vision daytime or high-luminance vision where only the cone optic cells are active Note 1 to entry: In photopic vision, the 555 nm wavelength (green-yellow) is the human eyes maximum sensitivity. 3.8 scotopic vision night-time or

30、 in low luminance vision where only the rod optic cells are active Note 1 to entry: In scotopic vision, the 505 nm (blue-green or turquoise.) wavelength is the human eyes maximum sensitivity. 4 Fluorescent techniques, inspection booth, lights and visual ergonomics 4.1 Lights: UV-A beam spectral char

31、acteristics 4.1.1 General UV-A LED lamps technology needs to be understood since they are used for lighting in NDT methods using fluorescent materials, ISO 3059 deals with requirements but the following clauses provide technical explanation and guidance for the use of UV-A lamps in NDT. 4.1.2 Symmet

32、ry of the spectrum around the centroid wavelength The optical brighteners used in penetrants and some fluorescent pigments used in the MT detection media usually absorb 80 % of the radiation energy between 340 nm and 380 nm. Therefore for UV-A LEDs a symmetrical, Gaussian emission spectrum around th

33、e peak output wavelength is recommended. PD CEN/TS 17108:2017CEN/TR 17108:2017 (E) 6 The optical brighteners used in penetrants and some fluorescent pigments used in the MT detection media have an absorption peak between 360 nm and 370 nm. The centroid wavelength of the UV-A source shall be close to

34、 the peak absorption so that the radiation is more efficient to excite the dyes of the fluorescent penetrants and the pigments of the fluorescent detection media. These conditions are met when the centroid wavelength is close to the central wavelength (emission peak). 4.1.3 Unwanted visible light of

35、 the UV-A spectrum: limitation of the emission 380 nm The eye is sensitive to wavelengths greater than 380 nm. The 380 nm to 420 nm area (violet light and extreme violet) is emitted as a stray light by most of UV-A source. This violet can cause, as UV-A, visual blue haze by exciting some proteins in

36、 the eye. Vision of the direct violet and indirect blue haze effect leads to increasing the noise which impairs the detection of indications. Manufacturer shall minimize the emission of violet light by carefully selecting the LEDs, the filter, and using a well-controlled thermal management system to

37、 prevent any drift leading to an increase of unwanted violet output. This visible violet to which the eye is sensitive is not fully filtered by Wood filters nor by all the UV-blocking goggles; this comes at the cost of the contrast at the inspection stage on all types of metal parts (except yellow m

38、etals that naturally absorb violet and blue). Bright surfaces strongly reflect violet light, requiring the inspector to guide the relative position of the parts to avoid this reflection; matt surfaces turn to a purplish colour background regardless of the orientation of the beam. 4.1.4 Radiometric s

39、pecifications: UV-A/violet ratio Violet light is the 380 nm 420 nm area. In order to take into account the data described in the previous clause, the manufacturer or the supplier shall state the measurements relevant to the UV-A/ violet ratio in the product data sheet (user manual, procedure, produc

40、t manual, etc.). The result may be given in the form of a ratio calculated by analysing the spectrum with a spectrophotometer positioned at the beam centre, then, by discriminating the UV-A area up to 380 nm and the violet area, 380 nm to 420 nm. For professional purposes, UV-A sources should be use

41、d so as to minimize their effect, as follows: a Wood filter or similar, to remove violet as much as possible, shall be an integral part of the source. PD CEN/TS 17108:2017CEN/TR 17108:2017 (E) 7 Key X wavelength (nm) Y relative scale 1 green curve: UV-A spectra with Wood filter in the violet range 2

42、 purple curve: UV-A spectra without Wood filter in the violet range Figure 1 Example of reduction of the violet light 380 nm to 420 nm by a source fit with a Wood filter PD CEN/TS 17108:2017CEN/TR 17108:2017 (E) 8 Key X wavelength (nm) Y relative irradiance 1 central wavelength: 368,9 nm 2 centroid

43、wavelength: 369,5 nm 3 full width half maximum: 10,9 nm NOTE The left side in light violet colour corresponds to UV-A and the right side in dark violet colour to visible violet Figure 2 Example of measured spectrum 4.1.5 Thermal management (cooling), sustaining performances A poor thermal management

44、 will cause beam instability, spectrum shift with violet increase and power loss. In case of LED sources, the elements ensuring the extraction of calories shall be maintained in an optimal operation condition (e.g. dust filter replacement, removing dust deposits on coolers, renewal of thermal paste

45、during LED maintenance etc.). An automatic circuit-breaker system shall be built-in to take action in case of overheating; leading to a non-compliance of the beam (wavelength shift beyond 370 nm and violet versus UV-A ratio increase for LEDs). Regarding LED sources: during their use, no decrease of

46、power, likely to reduce the irradiance without notice by the operator, shall ever be acceptable as a means to prevent overheating. PD CEN/TS 17108:2017CEN/TR 17108:2017 (E) 9 For UV source not intended to be used continuously the manufacturer shall state the maximum time to be used. 4.2 UV-A beam ge

47、ometrical characteristics 4.2.1 General The variety of inspection circumstances and the variety of part sizes and localizations, such as large individual parts or grapes of small sized parts, need our attention to choose adequate lighting scenari; a good choice leads to visual performance enhancemen

48、t and better POD. 4.2.2 Geometric consideration for use The pattern and the beam size of the source in use should be fitted to the surface of the area inspected on the parts and the arrangement thereof (if parts are displayed as “clusters” or as “trays” of several parts). The way the human eye works

49、 and, particularly, the roles of the fovea and of the peripheral vision shall be taken into account during inspection. Therefore, several types of beam patterns should be considered: wide or narrow, with sharp or progressive edges to adapt the beam to the spatial conditions and orientation on the inspection zone to use the full capability of detection of the human vision. A practical test of the source for the specific application is always helpful before choosing the beam pattern. The field of vision may be considered as three areas