CEN/TR 17108:2017

SLOVENSKI STANDARD
01-december-2017
Neporušitvene preiskave - Osvetlitev pri preiskavah s penetranti in magnetnimi
delci, dobra praksa
Non-destructive testing - Lighting in penetrant and magnetic particle testing, good
practice
Zerstörungsfreie Prüfung - Beleuchtung in Eindring- und Magnetpulverprüfung ,
bewährte Verfahren
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Ta slovenski standard je istoveten z: CEN/TR 17108:2017
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TR 17108
TECHNICAL REPORT
RAPPORT TECHNIQUE
June 2017
TECHNISCHER BERICHT
ICS 19.100
English Version
Non-destructive testing - Lighting in penetrant and
magnetic particle testing, good practice
Essais non destructifs - Bonnes pratiques d'éclairage Zerstörungsfreie Prüfung - Beleuchtung in Eindring-
lors des contrôles par ressuage et par magnétoscopie und Magnetpulverprüfung, bewährte Verfahren

This Technical 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, Greece, 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
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR 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 Ref. No. CEN/TR 17108:2017 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
1 Scope . 4
2 Normative references . 4
3 Terms 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 the 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 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
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
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 Measurements . 25
6.1 Radiometers and luxmeters characteristics/specifications . 25
6.2 Irradiance measurement . 25
7 Actinic Blue . 26
European foreword
This document (CEN/TR 17108:2017) has been prepared by Technical Committee CEN/TC 138 “Non-
destructive testing”, 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.
1 Scope
This Technical 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 MT. 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 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 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 — Ultraviolet 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 (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 definitions
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
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 black 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 vision 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 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 characteristics
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 Symmetry 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 the peak output wavelength is recommended.
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 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 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 the eye.
Vision of the direct violet and indirect blue haze effect leads to increasing the noise which impairs the
detection of indica
...