Personal eye-protection - Optical test methods

This European standard specifies optical test methods for eye-protectors, the requirements for which are contained in other EN's. Alternative methods may be used if shown to be equivalent. Non-optical test methods are given in EN 168. A definition of terms is given in EN 165.

Persönlicher Augenschutz - Optische Prüfverfahren

Diese Europäische Norm legt optische Prüfverfahren für Augenschutzgeräte fest, für die die Anforderungen in anderen Europäischen Normen enthalten sind.
Alternative Prüfverfahren dürfen verwendet werden, falls deren Gleichwertigkeit nachgewiesen wurde.
EN 168 enthält die nichtoptischen Prüfverfahren.
Anforderungen sind in EN 166 enthalten.
Die Begriffe sind in EN 165 definiert.

Protection individuelle de l'oeil - Méthodes d'essais optiques

La présente Norme européenne spécifie les méthodes d'essais optiques pour les protecteurs oculaires dont les spécifications sont données dans d'autres EN.
Il est possible d'utiliser d'autres méthodes s'il est démontré qu'elles sont équivalentes.
Les méthodes d'essais autres qu'optiques font l'objet de l'EN 168.
Les spécifications sont données dans l'EN 166.
Une définition des termes employés est donnée dans l'EN 165.

Osebno varovanje oči - Metode optičnih preskusov

General Information

Status
Published
Publication Date
13-Nov-2001
Current Stage
9060 - Closure of 2 Year Review Enquiry - Review Enquiry
Due Date
03-Jun-2020
Completion Date
03-Jun-2020

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Personal eye-protection - Optical test methodsProtection individuelle de l'oeil - Méthodes d'essais optiquesPersönlicher Augenschutz - Optische Prüfverfahren13.340.20Varovalna oprema za glavoHead protective equipmentICS:SIST EN 167:2002enTa slovenski standard je istoveten z:EN 167:200101-junij-2002SIST EN 167:2002SLOVENSKI

STANDARDSIST EN 167:19961DGRPHãþD

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 167November 2001ICS 13.340.20Supersedes EN 167:1995English versionPersonal eye-protection - Optical test methodsProtection individuelle de l'oeil - Méthodes d'essaisoptiquesPersönlicher Augenschutz - Optische PrüfverfahrenThis European Standard was approved by CEN on 3 September 2001.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the 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 translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36

B-1050 Brussels© 2001 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 167:2001 E

EN 167:2001 (E)2ContentspageForeword......................................................................................................................................................................31Scope..............................................................................................................................................................42Normative references....................................................................................................................................43Test for spherical, astigmatic and prismatic refractive powers................................................................43.1Testing unmounted oculars covering one eye...........................................................................................43.2Testing unmounted oculars covering both eyes and mounted oculars (spectacles, gogglesand face-shields)............................................................................................................................................64Light diffusion test.........................................................................................................................................84.1Principle..........................................................................................................................................................84.2Test methods..................................................................................................................................................85Assessment of quality of material and surface........................................................................................146Determination of transmittance..................................................................................................................147Determination of variations in luminous transmittance..........................................................................157.1Unmounted oculars covering one eye.......................................................................................................157.2Mounted oculars and unmounted oculars covering both eyes..............................................................167.3Method to correct transmittance for variations in thickness of the ocular...........................................178Determination of spectral reflectance in infrared.....................................................................................18Annex A (normative)

Method for measuring spherical and astigmatic refractive powers over smallareas..............................................................................................................................................................19A.1Principle........................................................................................................................................................19A.2Apparatus.....................................................................................................................................................19A.3Measurements..............................................................................................................................................20Annex B (informative)

Uncertainty of measurement and results interpretation.................................................25B.1Test report and uncertainty of measurement...........................................................................................25Annex ZA (informative)

Clauses of this European Standard addressing essential requirements or otherprovisions of EU Directives........................................................................................................................27

EN 167:2001 (E)3ForewordThis document has been prepared by Technical Committee CEN /TC 85, "Eye-protective equipment", thesecretariat 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 orby endorsement, at the latest by May 2002, and conflicting national standards shall be withdrawn at the latest byMay 2002.This European Standard replaces EN 167:1995.This document has been prepared under a mandate given to CEN by the European Commission and the EuropeanFree Trade Association, and supports essential requirements of EU Directive(s).For relationship with EU Directive(s), see informative annex ZA, which is an integral part of this document.Annex A is normative. The annexes B and ZA are informative.According to the CEN/CENELEC Internal Regulations, the national standards organizations of the followingcountries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden,Switzerland and the United Kingdom.

EN 167:2001 (E)41 ScopeThis European Standard specifies optical test methods for eye-protectors, the requirements for which are containedin other ENs.Alternative methods may be used if shown to be equivalent.Non-optical test methods are given in EN 168.Specifications are given in EN 166.A definition of terms is given in EN 165.2 Normative referencesThis European Standard incorporates by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text, and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision. For undated references the latest edition of thepublication referred to applies (including amendments).EN 165, Personal eye-protection — Vocabulary.EN 166, Personal eye-protection — Specifications.EN 168, Personal eye-protection — Non-optical test methods.3 Test for spherical, astigmatic and prismatic refractive powersNOTEThe reference methods for assessment of refractive power are contained in 3.1 and 3.2.If during measurement using the telescope a doubling or other aberration of the image is observed then the ocularmay either be classified as a defective, or subjected to further examination using the method described in annex A.3.1 Testing unmounted oculars covering one eye3.1.1 Apparatus3.1.1.1 TelescopeA telescope with an aperture of nominally 20 mm and a magnification between 10 and 30, fitted with an adjustableeyepiece incorporating a reticule.3.1.1.2 Illuminated targetA target, consisting of a black plate incorporating the cut-out pattern shown in Figure 1, behind which is located alight source of adjustable luminance with a condenser, if necessary, to focus the magnified image of the lightsource on the telescope objective.The large annulus of the target has an outer diameter of (23,0 ± 0,1) mm with an annular aperture of(0,6 ± 0,1) mm. The small annulus has an inner diameter of (11,0 ± 0,1) mm with an annular aperture of(0,6 ± 0,1) mm. The central aperture has a diameter of (0,6 ± 0,1) mm. The bars are nominally 20 mm long and2 mm wide with a nominal 2 mm separation.

EN 167:2001 (E)53.1.1.3 FilterA filter with its maximum transmittance in the green part of the spectrum may be used to reduce chromaticaberrations.3.1.1.4 Calibration lensesLenses with positive and negative spherical refractive powers of 0,06 m-1, 0,12 m-1 and 0,25 m-1(tolerance ± 0,01 m-1).3.1.2 Arrangement and calibration of apparatusThe telescope and illuminated target are placed on the same optical axis (4,60 ± 0,02) m apart.The observer focuses the reticule and the target and aligns the telescope to obtain a clear image of the pattern.This setting is regarded as the zero point of the focusing scale of the telescope. The telescope shall be aligned sothat the central aperture of the target is imaged on the centre of the cross-line graticule. This setting is regarded asthe zero point of the prism scale.The focusing adjustment of the telescope is calibrated with the calibration lenses (3.1.1.4) so that a powerof 0,01 m-1 may be measured. Any other equivalent calibration method may be used.3.1.3 ProcedurePosition the ocular in front of the telescope in the as-worn position, or other position as specified by themanufacturer. If the as-worn position is unknown, or if no position is specified by the manufacturer then the ocularshall be positioned normal to the telescopic axis and the tests conducted at the geometric centre.3.1.3.1 Spherical refractive power and astigmatic refractive power3.1.3.1.1 Oculars without astigmatic refractive powerThe telescope is adjusted until the image of the target is clearly focussed. The spherical power of the ocular is thenread from the scale of the telescope.3.1.3.1.2 Oculars with astigmatic refractive powerThe target, or the ocular, is rotated in order to align the principal meridians of the ocular with the bars of the target.The telescope is focused firstly on one set of bars (measurement D1) and then on the perpendicular bars(measurement D2). The spherical power is the mean, 221DDthe astigmatic refractive power is the absolutedifference, 21DD, of the two measurements.NOTEDuring this process the best focus shall be used across the whole target for each meridian.3.1.3.2 Prismatic refractive powerThe ocular to be tested is placed in front of the telescope, and, if the point of intersection of the lines of the reticulefalls outside the image of the large circle, the prismatic power exceeds 0,25 cm/m. If the point of intersection of thelines of the reticule falls inside the image of the small circle of the target, the prismatic power is lessthan 0,12 cm/m.

EN 167:2001 (E)6Figure 1 — Telescope target (dimensions are given in 3.1.1.2)3.2 Testing unmounted oculars covering both eyes and mounted oculars (spectacles, gogglesand face-shields)3.2.1 Determination of the spherical and astigmatic refractive powerPosition the ocular such that it is in an “as-worn” orientation in front of the telescope.Measurements of spherical and astigmatic powers shall be taken based on the visual centre of the ocular using theprocedures specified in 3.1.3.1.3.2.2 Determination of the difference in prismatic refractive power3.2.2.1 ApparatusThe arrangement of the reference method is shown in Figure 2.3.2.2.2 ProcedureThe diaphragm LB1, illuminated by the light source, is adjusted in such a way that it produces an image on theplane B when the eye-protector (P) is not in position. The eye-protector is placed in front of the lens L2

in the as-worn position so that the axis of the eye-protector is parallel to the optical axis of the test assembly. Adjustable tilteye-protectors are positioned with their oculars normal to the optical axis of the test equipment.Measure the vertical and horizontal distances between the two displaced images arising from the two ocularregions of the eye-protector.These distances in centimetres are divided by two to give the horizontal and vertical prismatic differencesin centimetres per metre.If the light paths which correspond to the two eye regions cross, the prismatic refractive power is `base in' and if thelight paths do not cross, it is `base out'.

EN 167:2001 (E)7Dimensions in millimetres (nominal unless toleranced)KeyLaLight source, for example, small filament lamp, laser with wavelength of (600

70) nm, etc.JInterference filter with peak transmittance in the green part of the spectrum (required only if a filament lamp is used as the light source)L1Achromatic lens, focal length between 20 mm and 50 mmLB1Diaphragm, diameter of aperture 1 mm nominalPEye-protectorLB2Diaphragm as shown in detail AL2Achromatic lens, 1 000 mm nominal focal length and 75 mm nominal diameterBImage planeaAs close as possible.bX = (32,0

0,2) mm or (27,0

0,2) mm depending on the size of the head-form specified in EN 168.Figure 2 — Arrangement of apparatus for measurement of prismatic difference

EN 167:2001 (E)84 Light diffusion test4.1 PrincipleThe luminance (Ls) of an illuminated ocular is a measure of its light diffusion and is proportional to the illuminance(E). The proportionality factor is the luminance factor l = Ls/E, which is expressed in candelas per square metre perlux lx)m/cd(2.To obtain a factor l* which is independent of the transmittance of the ocular, the luminance factor is divided by thetransmittance .ELls*This quantity is known as the reduced luminance factor and is expressed in the same units as the luminance factor.NOTEMost oculars have diffusion properties which are symmetrical about the optical axis. For these oculars, the meanvalue of the reduced luminance factor is measured within an angle limited by the two cones shown in Figure 3. This mean valuedepends upon values

and .Key1Incident light on optical axis2Diffused light3OcularFigure 3 — Diffusion angles4.2 Test methodsTwo test methods are specified which use the same measurement principle. The `basic method' detailed in 4.2.1may be used for oculars without corrective effect and for all shade numbers. The `simplified method' detailedin 4.2.2 has to be used for oculars with corrective effect.The results obtained with the two methods may be considered to be equivalent; whichever method is used therelative measurement uncertainty for the reduced luminance factor shall not be greater than 25 %.Measurements of light diffusion shall be taken at the visual centre of the ocular. If the visual centre is not knownthen the geometric centre shall be used.NOTEVisual centre is as defined in EN 166.

EN 167:2001 (E)94.2.1 Basic method4.2.1.1 ApparatusThe arrangement is shown in Figure 4.The spherical concave mirror H1 forms an image of light L of identical dimensions at diaphragm LB. The sphericalconcave mirror H3 forms an image of diaphragm LB in the plane of diaphragms BL and BR. The achromatic lens A ispositioned immediately behind the diaphragm so that a reduced image of the test sample in position P appears ondiffusing screen MS. The image of iris diaphragm IB1 is formed at the same time as IB2.The arrangement collects all the light originating from the filter between angles

= 1,5 and

= 2 in relationto the optical axis.4.2.1.2 ProcedureThe ocular is placed in the parallel beam at position P, then diaphragm BL is put in place. The flux 1L falling ontothe photodetector corresponds to the undiffused light transmitted by the sample. Diaphragm BL is then replaced byannular diaphragm BR; flux 1R falling onto the photodetector corresponds to the total diffused light originating fromthe filter and from the apparatus. The test sample is then placed at position P. The flux 2R which then falls ontothe photodetector corresponds to the diffused light coming from the apparatus only.The difference 1R - 2R corresponds to the light diffused by the filter. The mean reduced luminance factor l* forthe solid angle

is calculated from the preceding fluxes by means of the formula:1L2R1R*llwhere1R, 2Rare the luminance fluxes with the annular diaphragm;1Lis the luminous flux with the circular diaphragm;is the solid angle defined by the annular diaphragm.

EN 167:2001 (E)10KeyLHigh-pressure xenon lamp (for example XB0 150 W or CSX150 W)H1Spherical concave mirror; nominal focal length 150 mm; nominal diameter 40 mmH2Spherical concave mirror; nominal focal length 300 mm; nominal diameter 40 mmH3Spherical concave mirror; nominal focal length 300 mm; nominal diameter 70 mmAAchromatic lens; nominal focal length 200 mm; nominal diameter 30 mmU1, U2Flat mirrorsBRAnnular diaphragm; diameter of outer circle (21,0 ± 0,1) mm, diameter of inner circle (15,75 ± 0,10) mm. See note belowBLCircular diaphragm; diameter of aperture (7,5 ± 0,1) mmMPhotomultiplier corrected according to curve V () with diffusing screenIB1Iris-diaphragm to adjust diameter of field of measurementIB2Iris-diaphragm to eliminate edge effects from IB1LBCircular diaphragm, diameter of aperture (1,0 ± 0,1) mmMSDiffusing screenP, PPositions of test ocularFigure 4 — Arrangement of apparatus for measurement of light diffusion - basic methodNOTEThe diameters of the annular diaphragm circles shall be measured to an uncertainty not exceeding 0,01 mm in orderthat the solid angle

may be determined accurately; any deviation from the nominal diameters shall be taken into account bycalculation.

EN 167:2001 (E)114.2.2 Simplified method4.2.2.1 ApparatusThe test arrangement is shown in Figure 5.NOTEThe measurement principle is identical to that given in 4.2.1, but the diameter of the measuring zone is smaller(approximately 2,5 mm) and the test arrangement is simplified.The beam of the laser (L) is expanded using the two lenses L1 and L2 and is directed towards the measuring pointof the ocular (P). Ocular (P) is positioned in such a way that it can rotate around the axis of the beam.The deviation of the beam is a function of the prismatic refractive power at the measuring point.The annular or circular diaphragm, whichever is chosen, is at a distance of (400 ± 2) mm from the centre of theocular.The lens A then produces the image of the centre of the ocular on the photoreceptor S.The part of the test arrangement, comprising the diaphragms, the lens and the receptor, is designed to rotate aboutthe vertical axis through the centre of the ocular.The ocular and the detector part of the apparatus have to pivot in order to compensate for any prismatic refractivepower of the ocular.NOTEFor oculars wi

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