BRITISH STANDARD BS EN 25580:1992ISO 5580:1985

Specification for

Minimum requirements for industrial radiographic illuminators for non-destructive testing

This European Standard EN 25580:1992 has the status of a British Standard

BS EN 25580:1992

This British Standard, having been prepared under the direction of the General Mechanical Engineering Standards Policy Committee, was published under the authority of theStandards Board and comes into effect on 15 June 1992

© BSI 02-1999

The following BSI references relate to the work on this standard:Committee reference GME/23Draft for approval 90/80071 DC

ISBN 0 580 20471 5

Cooperating organizations

The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries.

Austria Oesterreichisches NormungsinstitutBelgium Institut belge de normalisationDenmark Dansk StandardiseringsraadFinland Suomen Standardisoimisliito, r.y.France Association française de normalisationGermany Deutsches Institut für Normung e.V.Greece Hellenic Organization for StandardizationIceland Technological Institute of IcelandIreland National Standards Authority of IrelandItaly Ente Nazionale Italiano di UnificazioneLuxembourg Inspection du Travail et des MinesNetherlands Nederlands Normalisatie-instituutNorway Norges StandardiseringsforbundPortugal Instituto Portuguès da QualidadeSpain Asociación Española de Normalización y CertificaciónSweden Standardiseringskommissionen i SverigeSwitzerland Association suisse de normalisationUnited Kingdom British Standards Institution

Amendments issued since publication

Amd. No. Date Comments

BS EN 25580:1992

© BSI 02-1999 i

Contents

PageCooperating organizations Inside front coverNational foreword iiForeword of EN 25580 21 Scope and field of application 32 Characteristics of radiographic illuminators 33 Determination of certain characteristics 44 Marking 45 Recommendations for use 4Figure — Light luminance measurement 5National appendix NA (informative) Inside back cover

BS EN 25580:1992

ii © BSI 02-1999

National foreword

This British Standard has been prepared under the direction of the General Mechanical Engineering Standards Policy Committee and is the English language version of EN 25580:1992 “Non-destructive testing — Industrial radiographic illuminators — Minimum requirements” published by the European Committee for Standardization (CEN).EN 25580:1992 is identical with ISO 5580:1985 published by the International Organization for Standardization (ISO).National appendix NA gives the constitution of the committees responsible for UK participation in the preparation of this standard.A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application.

Compliance with a British Standard does not of itself confer immunity from legal obligations.

Summary of pagesThis document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 6, an inside back cover and a back cover.This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.

EUROPEAN STANDARD

NORME EUROPÉENNE

EUROPÄISCHE NORM

EN 25580

April 1992

UDC 620.179.152.05:620.186

Descriptors: Non-destructive tests, industrial radiography, radiographic illuminators, equipment specifications, screens: Display, luminance, divergence, lighting, optical measurements, marking

English version

Non-destructive testing Industrial radiographic illuminators Minimum requirements

(ISO 5580:1985)

Essais non destructifs — Négatoscopes utilisés en radiographie industrielle — Exigences minimales(ISO 5580:1985)

Zerstörungsfreie Prüfung — Betrachtungsgeräte für die industrielle Radiographie — Minimale Anforderungen (ISO 5580:1985)

This European Standard was approved by CEN on 1992-03-27. CEN membersare bound to comply with the CEN/CENELEC Internal Regulations whichstipulate the conditions for giving this European Standard the status of anational standard without any alteration.Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to anyCEN member.This European Standard exists in three official versions (English, French,German). A version in any other language made by translation under theresponsibility of a CEN member into its own language and notified to theCentral Secretariat has the same status as the official versions.CEN members are the national standards bodies of Austria, Belgium,Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland andUnited Kingdom.

CEN

European Committee for StandardizationComité Européen de NormalisationEuropäisches Komitee für Normung

Central Secretariat: rue de Stassart 36, B-1050 Brussels

© CEN 1992 Copyright reserved to all CEN membersRef. No. EN 25580:1992 E

EN 25580:1992

© BSI 02-19992

ForewordIn 1990, ISO 5580:1985 was submitted to the CEN Primary Questionnaire procedure.Following the positive result of this procedure, the CEN Technical Board, agreed to submit ISO 5580:1985, without modifications, to Formal Vote. The result of the Formal Vote was positive.National standards identical to this European Standard shall be published at the latest by 92-10-31 and conflicting national standards shall be withdrawn at the latest by 92-10-31.In accordance with the CEN/CENELEC Common Rules, the following countries are bound to implement this European Standard:Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.

EN 25580:1992

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1 Scope and field of applicationThis International Standard specifies the minimum requirements for industrial illuminators used for viewing radiographs.The function of the illuminator is to allow the viewing of radiographs.The illuminator shall guarantee the same safety of personnel as an electric apparatus with maximum voltage, insulation and earthing which is required by corresponding safety standards of electrotechnics in each country where these are applied.

2 Characteristics of radiographic illuminators2.1 Mechanical construction

An illuminator consists of the housing with one of the sides being the viewing screen illuminated from the inside. This screen can itself be the diffusing screen. This housing may also contain a system for thermal protection of the radiographs; this system may or may not be ventilated.For the viewing of wet radiographs, the illuminator shall be so designed as to prevent penetration of the liquid if the radiograph comes into contact with the screen.

2.2 Viewing screen

The screens shall be easy to clean and shall be made of a material which is resistant to scratching during cleaning processes recommended by the manufacturer and during film viewing.NOTE The screen may be a combination of elements, all of which should be resistant to heat in terms of deformation and discoloration.The size of the screens shall allow the viewing of a radiograph without excessive glare reaching the eyes of the operator. Should the illuminator be used for viewing radiographs of different sizes, a system of covering masks shall be provided.

2.3 Luminance

The screen luminance required depends on the density of the radiographs. The following luminance levels are recommended for the perception of information at various density levels.

The luminance (or brightness) of the illuminated radiograph shall be not less than:

— 30 cd/m2 for film densities < 2,5— 10 cd/m2 for film densities > 2,5

and, wherever possible, approximately 100 cd/m2 or higher. These minimum values require the following screen luminance:

NOTE The illuminator may be provided with a device for continuous control of screen luminance.

2.4 Colour of light

The colour of the light used to illuminate the radiograph is normally white. However, in the case of a film with an emulsion type yielding a monocoloured image, light with adapted colours may be used if they have been recommended by the film manufacturers.

2.5 Diffusion of light

If the illuminator has a diffusing screen, the light shall be sufficiently divergent so that both eyes of the observer receive rays from all parts of the screen. The diffusion factor s9 shall exceed 0,7 (see 3.1).

2.6 Uniformity of illumination

The screen shall be uniformly illuminated, the uniformity factor g being higher than 0,5 (see 3.2).

2.7 Disturbing light

The housing, blinds and covering masks shall be constructed in such a manner that no disturbing light hinders the viewing of the radiographs (see clause 3).

2.8 Anti-glare device

Each illuminator shall be fitted with an anti-glare device which, by manual or automatic operation, prevents the operator from being subjected to excessive glare when the radiograph is removed.

Film densityMinimum screen luminance

cd/m2

11,522,533,544,5

3001 0003 000

10 00010 00030 000

100 000300 000

EN 25580:1992

4 © BSI 02-1999

2.9 Heating

Appropriate precautions shall be taken to ensure that the temperature of the housing does not exceed 60 °C at the usual contact surfaces after 1 h of intermittent operation (50 % switched on with maximum of 15 s duration at an ambient temperature of 20 °C). Further precautions shall be taken to ensure that a radiograph of density 2 does not warp after a continuous viewing time of 1 min and 1 h of intermittent operation of the illuminator.

3 Determination of certain characteristicsAll photometric measurements shall be carried out in a dark room. The luminance meter has to be used in the middle part of its measuring scale. Moreover, light escaping from the illuminator even when the viewing screen is completely masked shall not affect the measurements.

3.1 Divergence and dispersion of light (of diffusing screens)

The luminance shall be measured on a semi-circle, the centre of which is the centre of the screen and the diameter of which is approximately the same as the maximum dimension of the screen, but at least 50 cm. The luminance shall be measured with the aid of an appropriate luminance meter, the sensitive surface of which is a tangent to the curve of the circle (see the Figure).These measurements shall be made at angles of 45° (L45), 20° (L20) and 5° (L5) related to the normal. The diffusion factor s9 shall be calculated according to the formula

The measurements shall be made successively in both senses of rotation.

3.2 Uniformity of screen luminance

The measurements shall be made with the aid of an illumination photometer or other suitable instrument. If the screen is rectangular, it shall be divided into squares, each side of the squares measuring 3,5 cm, the luminance of each being measured separately. If the screen is circular, the same basic procedure shall be followed. In both cases, the network of the squares shall be so arranged that the middle square is centred in the middle of the screen.

The average of the four highest and the average of the four lowest results shall be found, which give the average arithmetical values of the luminance L max and L min. The uniformity factor g shall then be calculated according to the formula

3.3 Nominal power consumption

The nominal power consumption is the number of watts being consumed by the illuminator after it has been in continuous operation at full luminance for a minimum period of 30 min.

4 MarkingA plate which is attached to the illuminator shall give the following information :

a) nominal operating voltage or permissible voltage range;b) nominal main frequency or permissible frequency range;c) whether for use with both direct and alternating current or only with one or the other;d) nominal power consumption;e) maximum luminance in candelas per square metre.

5 Recommendations for useOperating instructions shall be provided with each illuminator to indicate:

a) the operation of the apparatus;b) instructions for the mounting and replacement of lamps and screens;c) care and maintenance;d) safety precautions;e) frequency of checking luminance levels.

s9L45 L20+

2 L5-------------------------=

gLminLmax-------------=

BS EN 25580:1992

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Figure — Light luminance measurement

6 blank

BS EN 25580:1992

© BSI 02-1999

National appendix NA (informative)The United Kingdom participation in the preparation of this European Standard was entrusted by the General Mechanical Engineering Standards Policy Committee (GME/-) to Technical Committee GME/23 upon which the following bodies were represented:

Aluminium FederationAssociated Offices Technical CommitteeAssociation of Consulting EngineersBEAMA Ltd.BNF Metals Technology CentreBritish AirwaysBritish Chemical Engineering Contractors’ AssociationBritish Gas plcBritish Institute of Non-destructive TestingBritish Photographic AssociationBritish Steel IndustryElectricity Industry in United KingdomHealth and Safety ExecutiveInstitute of PhysicsInstitute of Quality AssuranceLight Metal Founders’ AssociationLloyd’s Register of ShippingMinistry of DefenceNAMASPower Generation Contractors’ Association (BEAMA Ltd.)Royal Society of ChemistrySociety of British Aerospace Companies LimitedSociety of Motor Manufacturers and Traders LimitedSteel Casting Research and Trade AssociationThe Welding Institute

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