1、CEN EN*25580 92 W 3404589 0025873 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 25580 April 1992 CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Noimung Central Secretariat: rue de Stassart 36, B-1050 Brussels O CEN 1992 Copyright reserved to a
2、ll CEN members Ref. No. EN 25580 : 1992 E _. UDC 620.179.152.05 : 620.186 Desciiptois: Non-destructive tests, industrial radiography, radiographic iiluminators, equipment specifications, screens : Display, luminance, divergence, lighting, optical measurements, marking English version Non-destructive
3、 testing - Industrial radiographie illuminators - Minimum requirements (IS0 5580 : 1985) Essais non destructifs - Ngatoscopes utiliss en radiographie industrielle - Exigences minimales Radiographie - Minimale Anforderungen (IS0 5580 : 1985) Zerstrungsfreie Prfung - Betrachtungsgerte fr die industrie
4、lle (IS0 5580 : 1985) This European Standard was approved by CEN on 1992-03-27. CEN members are bound to comply with the CENKENELEC 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 bib
5、liographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, Geiman). A version in any other language made by translation under the responsibility
6、of a CEN member into its own language and notified to the Central 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, Noiway, Portugal
7、, Spain, Sweden, Switzerland and United Kingdom. CEN EN*Z5580 92 U 3404589 0025872 T Page 2 EN 25580 : 1992 Foreword In 1990, IS0 5580 : 1985 was submitted to the CEN Primary Questionnaire procedure. Following the positive result of this procedure, the CEN %chnical Board, agreed to submit IS0 5580 :
8、 1986, 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to this European Standard shall be published at the latest by 92-10-31 and conflicting national standards shall be withdrawn at the latest by 92-10-31.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 CENKEN
9、ELEC 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. CEN EN*Z5580 92 3404589 0025873 1
10、Page 3 EN 25580 : 1992 Non-destructive testing - Industrial radiographic illuminators - Minimum requirements 1 Scope and field of application This International Standard specifies the minimum require- ments for industrial illuminators used for viewing radiographs. The function of the illuminator is
11、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 o
12、f radiographic illuminators 2.1 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;
13、 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 whic
14、h is resistant to scratching during cleaning pro- cesses 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
15、 a radiograph without excessive glare reaching the eyes of the operator. Should the illuminator be used for viewing radiographs of dif- ferent 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 lum
16、inance 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/m* for film densities 2,5 and, wherever possible, approximately 100 cd/m2 or higher, These minimum values require
17、the following screen luminance : - Minimum screen luminance cdIrn2 Film density 1 2 2.5 3 3,5 4 4.5 1,5 300 1 o00 3 O00 10 O00 10 O00 30 O00 100 O00 300 O00 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 us
18、ed to illuminate the radiograph is nor- mally 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, t
19、he light shall be suffi- ciently divergent so that both eyes of the observer receive rays from all parts of the screen. The diffusion factor o 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)
20、. 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). CEN EN825580 92 E 3404589 0825874 3 E Page 4 EN 25580 : 1992 2,8 Anti-glare device Each illuminator shall be fitted with
21、 an anti-glare device which, by manual or automatic operation, prevents the operator from being subjected to excessive glare when the radiograph is removed. 2.9 Heating Appropriate precautions shall be taken to ensure that the temperature of the housing does not exceed 60 OC at the usual contact sur
22、faces after 1 h of intermittent operation (50 % switched on with maximum of 15 s duration at an ambient temperature of 20 OC). Further precautions shall be taken to ensure that a radiograph of density 2 does not warp after a con- tinuous viewing time of 1 min and 1 h of intermittent operation of the
23、 illuminator. 3 Determination of certain characteristics All 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 illumi- nator even when the viewing screen is completely masked s
24、hall not affect the measurements. 3.1 (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 measur
25、ed 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). Divergence and dispersion of light Figure - Light luminance measurement CEN EN*K25580 92 = 3404589 0025875 5 W Page 5 EN 25580 : 1992 These measurements shall b
26、e made at angles of 45 (L4d, 20 Lz0) and 5 L5) related to the normal. The diffusion factor o 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 illum
27、ination photometer or other suitable instrument. If the screen is rec- tangular, 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 net
28、work 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 arithmeti- cal values of the luminance Lma, and Lmin. The uniformity factor g shal
29、l then be calculated according to the formula g=- Lmin L max 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 Marking A plate which is att
30、ached to the illuminator shall give the following information : a) nominal operating voltage or permissible voltage range; bl 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
31、; e) maximum luminance in candelas per square metre. 5 Recommendations for use Operating instructions shall be provided with each illuminator to indicate : a) the operation of the apparatus; b) and screens; instructionsfor the mounting and replacement of lamps c) care and maintenance; d) safety precautions; el frequency of checking luminance levels.
