Home

มอก. 1604–2553 - ราชกิจจานุเบกษา

1.
2. 1 5009
3. 1 1
4. av Ta o yu o if 7 v a a 1
5. IEC 60825 1 2007 03 Corrigendum 1 2008 08 1604 2553 IEC 60825 1 2007 03 IEC 2007 a a AM Vo 1 d v o vada IEC ag a E 1 1 a e M vao 3
6. 4 3B 4
7. e e
8. 180 1 1
9. 1 1604 2541 WA
10. 1 1 1604 2553 oA VA v 1 QJ v d a vy
11. IEC 60601 2 22 1561 1195 2236 IEC Guide 104 156 61010 1 LED
12. IEC IEC IEC Central office 3 rue de Varembe CH 1211 Geneva 20 Switzerland E mail inmail iec ch Web www iec ch 1604 2553 60825 1 IEC 2007 3 CONTENTS FORE 1 1133131313 6 110 9 1 Scope and 1 1 9 13 2 Normative references odeur eme boe ique a ties etica vn dante eme n 17 3 Terms and definitions 3 Don tese sd neon Dome vU peor eur CD Ree a DR oM E CRM 17 4 Engineering Specifications 2 0 mee nme hee n ener rennen 43 44 General remarks 3 3 31311111 1 dd 43 4 2 Protective housing 3 3 3 3 31 13 43 4 3 Access panels and safety interlocks sssssssesee ee 43 4 4 Remote interlock connector ssssssssesssssese me meme He nee hene 45 4 5 Marnalreset ED 45 4 6 KEY CONT Ol Cmm 47 4 7 Laser radiation emission warning cc ee cece ee cence ee ee eee emen 47 4 8 Beam stop or attenuator 2 222422244sneaosoi tinantanan ei ia 47 AQ CONIFOLS c
13. JUN eo 7 a 1604 2553 IEC 60825 1 2007 03 Aa 0 d 7 A Y d d Q7 AY d Q7 1 IEC 60825 1 2007 03 Safety of laser products Part 1 Equipment classification and requirements Corrigendum 1 2008 08 identical IEC
14. 3 1604 2553 IEC 60825 1 2007 03
15. 3 8 9 AEL 1 7 y yv a ve A ew v ga v v To di Y o 2 7 Q c e Y av g g 1 9 a 7 a Y 94 c
16. 2 a e d a v o d al w PR 5 A H 2 EC Guide 104 1997 The preparation of safety publications and the use of basic safety publications and group safety publications 1604 2553 IEC 60825 1 2007 03 e
17. 1 MPE
18. 1604 2553 60825 1 IEC 2007 151 Users are instructed by labelling not to stare into the beam i e to perform active protective reactions by moving the head or closing the eyes and to avoid continued intentional intrabeam viewing Class 3R Laser products that emit radiation that can exceed the MPE under direct intrabeam viewing but the risk of injury in most cases is relatively low because the AEL for Class 3R is only 5 times the AEL of Class 2 visible laser beams or the AEL of Class 1 for non visible laser beams The risk of injury increases with exposure duration and exposure is hazardous for deliberate ocular exposure Because of the lower risk fewer manufacturing requirements and control measures for the user apply than for Class 3B The risk is limited because of unintentional exposures would rarely reflect worst case conditions of e g beam alignment with the pupil worst case accommodation e the inherent safety margin in the MPE natural aversion behaviour for exposure to bright light for the case of visible radiation and by the response to heating of the cornea for far infrared radiation Dazzle flash blindness and afterimages may be caused by a beam from a Class 3H laser product in the visible wavelength range particularly under low ambient light conditions This may have indirect general safety implications resulting from temporary disturbance of vision or from startle reactions Such visua
19. 2eeeeeeeeceeceeenennnninnnnnnens 63 5 11 Warning for visible laser radiation 2 2 0 eee cece cece eee ee m 63 6 Other informational requirements ssssse I mH ere 63 6 1 Information for the I meme He mene hen e Hen rennen 63 6 2 Purchasing and servicing information essesssseee ee 67 7 Additional requirements for specific laser products 2 2222 6 67 7 1 Other parts of the standard series IEC 60825 sss 67 2 Medical laser products iet retoque 69 7 8 Laser processing 8 22 69 TA Electric toys ioo 1 0 69 7 5 Consumer electronic Products 2202 69 8 0 69 84 aa aa ad ac RRENA 69 8 2 Classification responsibilities ecssssseee mm 71 8 3 Classification rules oie ace 111111 11 7 71 1604 2553 60825 1 IEC 2007 5 9 Determination of the accessible emi
20. 1 0 0 103 Table 13 Limiting angle of acceptance vli ien sa doni pen va tes Vests wrath sah utaris 109 Table A 1 Maximum permissible exposure MPE for Cg 1 at the cornea for exposure to laser radiation 23 313 1 1 1 1 uua 115 Table A 2 Maximum permissible exposure MPE at the cornea for exposure to laser radiation from extended sources in the wavelength range from 400 nm to 1 400 nm retinal hazard seu 117 Table A 3 Maximum permissible exposure MPE of the skin to laser radiation 119 Table A 4 Aperture diameters for measuring laser irradiance and radiant exposure 119 Table D 1 Summary of pathological effects associated with excessive exposure to 0 167 Table D 2 Explanation of measurement apertures applied to the MPEs 175 Table E 1 Maximum radiance of a diffused source for Class 1 sss 181 Table F 1 Summary of the physical quantities used in this Part 1 2 187 Table F 2 Summary of manufacturer s requirements ssssssssssss ee 189 Table G 1 Overview of additional data in associated parts of IEC 60825 195 1604 2553 60825 1 IEC 2007 9 9 INTERNATIONAL ELECTROTECHNICAL COMMISSION SAFETY OF LASER PRODUCTS Part 1 Equipment classification and requirements FOREWORD The Internatio
21. 5 1604 2553 60825 1 IEC 2007 27 For a single pulse this is the duration between the half peak power point of the leading edge and the corresponding point on the trailing edge For a train of pulses or subsections of a train of pulses this is the duration between the first half peak power point of the leading pulse and the last half peak power point of the trailing pulse 3 32 errant laser radiation laser radiation which deviates from a defined beam path Such radiation includes unwanted reflections from beam path components and deviant radiation from misaligned or damaged components 3 33 exposure duration duration of a pulse or series or train of pulses or of continuous emission of laser radiation incident upon the human body For a train of pulses this is the duration between the first half peak power point of the leading pulse and the last half peak power point of the trailing pulse 3 34 extended source viewing viewing conditions whereby the apparent source at a distance of 100 mm or more subtends an angle at the eye greater than the minimum angular subtense amin Two extended source conditions are considered in this standard when considering retinal thermal injury hazards intermediate source and large source They are used to distinguish sources with angular subtenses of the apparent source a between amin and intermediate sources and greater than amax large sources See
22. If the NOHD includes the possibility of viewing through optical aids this is termed the extended NOHD ENOHD 3 63 operation performance of the laser product over the full range of its intended functions It does not include maintenance or service 3 64 photochemical hazard limit either an MPE or AEL which was derived to protect persons against adverse photochemical effects In the ultraviolet wavelength range the photochemical hazard limit protects against adverse effects on the cornea and lens while the retinal photochemical hazard limit as defined in the wavelength range from 400nm to 600nm protects against photoretinitis a photochemical retinal injury from exposure to radiation 3 65 protective enclosure physical means for preventing human exposure to laser radiation unless such access is necessary for the intended functions of the installation 3 66 protective housing those portions of a laser product including a product incorporating an embedded laser which are designed to prevent human access to laser radiation in excess of the prescribed AEL generally installed by a manufacturer 1604 2553 60825 1 IEC 2007 37 3 67 pulse duration time increment measured between the half peak power points at the leading and trailing edges of a pulse 3 68 pulsed laser laser which delivers its energy in the form of a single pulse or a train of pulses In this Part 1 the duration of a pul
23. b CAUTION CLASS 2 LASER RADIATION WHEN OPEN DO NOT STARE INTO THE BEAM if the accessible radiation does not exceed the AEL for Class 2 where the level of radiation is measured according to 9 2 h and 9 3 9 CAUTION CLASS 2M LASER RADIATION WHEN OPEN DO NOT STARE INTO THE BEAM OR VIEW DIRECTLY WITH OPTICAL INSTRUMENTS if the accessible radiation does not exceed the AEL for Class 2M where the level of radiation is measured according to 9 2 h and 9 3 d CAUTION CLASS 3R LASER RADIATION WHEN OPEN AVOID DIRECT EYE EXPOSURE if the accessible radiation does not exceed the AEL for Class 3R NOTE Labels using AVOID EXPOSURE TO THE BEAM in the second line would also be acceptable e CAUTION CLASS 3B LASER RADIATION WHEN OPEN AVOID EXPOSURE TO THE BEAM if the accessible radiation does not exceed the AEL for Class 3B f CAUTION CLASS 4 LASER RADIATION WHEN OPEN AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION if the accessible radiation exceeds the limits for Class 3B This information may be provided in more than one adjacent label on the product 33 1604 2553 60825 1 IEC 2007 63 5 9 2 Labels for safety interlocked panels Appropriate labels shall be clearly associated with each safety interlock which may be readily overridden and which would then permit human access to laser radiation in excess of the AEL of Class 1 Such labels shall be visible prior to and d
24. in the wavelength range of 302 5 nm to 4 000 nm the limiting angle of acceptance should not be larger than 0 1 rad for the thermal hazard limits Within the wavelength range of 400 nm to 1 400 nm for thermal hazard limits for the evaluation of an apparent source which consists of multiple points the angle of acceptance should be in the range of amin y Gmax see 8 3 d 64 1604 2553 60825 1 IEC 2007 125 For the determination of the MPE for sources with non circular emission patterns the value of the angular subtense of a rectangular or linear source is determined by the arithmetic mean of the two angular dimensions of the source Any angular dimension that is greater than ama or less than amin should be limited to amax or amin respectively prior to calculating the mean The retinal photochemical hazard limits do not depend on the angular subtense of the source and the source is measured with the angle of acceptance as specified above A 5 Extended source lasers The following corrections to the small source MPEs are restricted in most instances to viewing diffuse reflections and in some cases these could apply to laser arrays line lasers lasers with beam waist diameters above 0 2 mm and divergence angles above 2 mrad or extended source diffused laser products For extended source laser radiation for example diffuse reflection viewing at wavelengths from 400 nm to 1 400 nm
25. V rods and cones ZEN SASS CY CZ Pigment a epithelium Vitreous Choroid humour Retina ji Sclera Light VI A Exit of optic E m nerve M Receptor cells wee cones Pigment Lr Oi choroid paves epithelium wr LM Sclera IL E IEC 421 07 Figure D 1 Anatomy of the eye 82 1604 2553 60825 1 IEC 2007 161 In Figure D 1 section A is a diagram of the external features of a left eye The gap between the overlying lids limits the field of view FOV of the eye to an almond shape The main features of the front of the eye are labelled Section B is a diagrammatic horizontal cross section of a left eye The eye is divided into two parts the front or anterior chamber which is bounded by the cornea the iris and the lens and the back or posterior eye cup which is bounded by the retina and contains the gel like vitreous humour Section C is the inside of an intact eye seen through an ophthalmoscope This instrument directs a beam of light through the pupil and illuminates the inside of the eye and so allows it to be seen The picture so viewed is referred to as the fundus It looks reddish but the major retinal vessels can be clearly seen Other prominent features are the whitish optic disc and the fovea The fovea is a small depression in the retinal surface which may be more pigmented than the surrounding retina and is the area of most acute vision The fovea is
26. and ROCKWELL B A Proposed maximum permissible exposure limits for ultrashort laser pulses Health Phys 76 4 349 354 SLINEY D H and WOLBARSHT M L Safety with Lasers and Other Optical Sources New York Plenum Publishing Corp 1980 SLINEY D ARON ROSA D DELORI F et al Adjustment of guidance for exposure of the eye to optical radiation from ocular instruments statement of a task group of the International Commission on Non lonizing Radiation Protection Applied Optics 44 11 2162 2176 2005 United Nations Environment Programme UNEP World Health Organization WHO International Radiation Protection Association IRPA Environmental Health Criteria No 23 Lasers and Optical Radiation Geneva WHO 1982 Of 1604 2553 60825 1 IEC 2007 179 Annex E informative MPEs and AELs expressed as radiance E 1 Background For large extended sources it may be easier to analyze potential retinal hazards by using the radiance of the source This annex is to provide users with a single table and graphs of maximum permitted radiances based on the AELs for Class 1 and Class 1M and corresponding MPE values in the retinal hazard wavelength region of 400 nm to 1 400 nm for viewing conditions where the angular subtense of the apparent source is assumed to be larger than amax By the law of conservation of radiance all extended sources that are diffused and emitting below the radiance level specified in
27. or therapeutic laser irradiation of any part of the human body 3 58 minimum angular subtense Omin value of angular subtense of the apparent source above which a source is considered an extended source MPEs and AELs are independent of the source size for angular subtenses less than amin NOTE amin 1 5 mrad 3 59 mode locking regular mechanism or phenomenon within the laser resonator producing a train of very short e g sub nanosecond pulses 19 1604 2553 60825 1 IEC 2007 35 While this may be a deliberate feature it can also occur spontaneously as self mode locking The resulting peak powers may be significantly greater than the mean power 3 60 most restrictive position position in the beam where the ratio of accessible emission over AEL is maximum NOTE Both the accessible emission and the AEL may depend on the position of the evaluation in respect to the beam 3 61 nominal ocular hazard area NOHA area within which the beam irradiance or radiant exposure exceeds the appropriate corneal maximum permissible exposure MPE including the possibility of accidental misdirection of the laser beam If the NOHA includes the possibility of viewing through optical aids this is termed the extended NOHA 3 62 nominal ocular hazard distance NOHD distance from the output aperture at which the beam irradiance or radiant exposure equals the appropriate corneal maximum permissible exposure MPE
28. the saccadic eye motion during fixation is generally overtaken by behavioural movements determined by visual task and it is quite unreasonable to assume that a light source would be imaged solely in the fovea for durations longer than 100 s For this reason the angle of acceptance ypp is increased linearly with the square root of t The minimal angular subtense amin correctly remains at the reference angle of 1 5 mrad for all exposure durations used in thermal retinal hazard evaluation However for photochemical retinal hazard assessment the concept is actually different as the angle ypp is a linear angle of acceptance for the measurement of irradiance and this is important to apply only for extended sources greater than approximately 11 mrad 88 1604 2553 60825 1 IEC 2007 173 Viewing distance In the case of a point type diverging beam source the hazard increases with decreasing distance between the beam waist and the eye The reason is that with decreasing distance the collected power increases while the size of the retinal image can be assumed to remain nearly diffraction limited for true laser sources down to a distance as close as 100 mm due to the accommodation capabilities of the eye The greatest hazard occurs at the shortest accommodation distance With further reduced distance the hazard to the unaided eye is also reduced as there is a rapid growth of the retinal image and a corresponding reducti
29. 1 050 3x107 C W 0 03 C J for t lt 0 06 Cys 0 5 W 0 5 W for t2 0 06 C4 s 1 050 to 1 400 1 5 x 108 W 0 15 J 0 5 W 1 400 to 109 1 25 x 108 W 0 125 J 0 5 W For correction factors and units see Table 10 The correction factors C to C and breakpoints T and T used in Tables 4 to 9 are defined in the following expressions see Table 10 51 1604 2553 60825 1 IEC 2007 99 Table 10 Correction factors and breakpoints for use in AEL and MPE evaluations nm C 1 700 to 1 150 C 100 018 1 150 1 150 to 1 200 C 8 1 200 to 1 400 0 1 5 mrad Omax 100 mrad N is the number of pulses contained within the applicable duration 8 3 f and Clause A 3 NOTE There is only limited evidence about effects for exposures of less than 10 9 for wavelengths less than 400 nm and greater than 1 400 nm The AELs for these emission durations and wavelengths have been derived by calculating the equivalent radiant power or irradiance from the radiant power or radiant exposure applying at 10 9 s for wavelengths less than 400 nm and greater than 1 400 nm NOTE 2 See Table 11 for aperture stops and Table A 4 for limiting apertures NOTE 3 In the formulae in Tables 4 to 9 and in these notes the wavelength must be expressed in nanometres the emission duration t must be expressed in seconds and a must be expressed in milliradians NOTE4 For emission durations which fall at the cell border values for i
30. 12 The aperture stop for the determination of the accessible emission as well as for the determination of the angular subtense of the apparent source is to be placed at a distance of 100 mm from the lens L1 and the diameter of this aperture stop shall be 3 5 mm NOTE The lens L1 is to represent a magnifying glass with a magnification of x 7 When diverging sources are placed at the focal point of the lens the radiation is collimated thereby affecting both the accessible emission as determined with the aperture stop as well as the angular subtense of the apparent source Since all distances are fixed for condition 2 it is not necessary to identify the most restrictive position 60825 1 IEC 2007 109 Source example 1604 2553 3 5 mm aperture stop fibre 2 680 3 5 mm 100 mm Radiometer gt 7 mm aperture Lt fa35mm 3 5 mm aperture stop Source example tao fibe m lt 7mm 8 5 mm d 1s FQ So o 100 mm lt gt lt gt Variable minimise angular subtense of image IEC 415 07 Figure 5 Experimental set up for the determination of the accessible emission above and the angular subtense of the apparent source below for condition 2 when an extended source is to be considered i e not using the default simplified evaluation b Angle of acceptance The angle of acceptance
31. 1x 1073 to 0 35 10 1x 1073 0 35 to 10 102 103 to to to 10 108 3 x 104 180 to 302 5 3 x 1010 W m 30 J m 2 302 5 to 315 315 to 400 2 4 x 104 W Thermal hazard t T4 7 9 x 1077 Cy Photochemical hazard 7 9 x 10 7 Co J t gt Ti 7 9 x 10 7 Co J 7 9 x 10 7 C J 7 9 x 10 3 7 9 x 10 6 W 400 to 450 450 to 500 500 to 700 5 8 x 10 9 J 1 0 1075 J 2 x 1077 J 7 x 1074 0 75 J 3 9 x 10 3 J 3 9 x 10 3 C3 J 3 9 x 10 C W and 3 9 x 10 4 W 3 9 x 10 4 W 700 to 1 050 0 9 1 0 10 75 C J 2x 10 7 Cy J 7 x 10 4 9 75 J 1 050 to 1 400 8 C 1041075 C 2 x 10 8 C J 3 5 x 10 3 0 75 C 3 9 x 10 4 C4 C W 1 400 to 1500 8x105W 8 x 1074 J 1 500 to 1800 8x106W 8x 10 3 J 1 800 to 2 600 8x 105 W 8x104J 2 600 to 4 000 8 x 104W 8 x 10 5 J 4 4 x 10 3 1025 J 1 0 x 10 2 W 4 000 to 106 1011 W m 100 J m 2 5 600 10 25 J m 1 000 W m 2 NOTE Laser products that meet the requirements for classification as Class 1 by satisfying measurement conditions 1 and 2 may be hazardous when used with viewing optics having greater than x7 magnification or ob jective diameters greater than those specified in Table 11 a For correction factors and units see Table 10 b The AELs for emission durations less
32. 3B and intentional viewing is unlikely For Class 3B Table 8 gives AEL 0 5 W Since the laser is only emitting 50 mW it does not exceed the AEL for Class 3B and could be classified as Class 3B However it may not always be obvious that the product would not satisfy the requirements of a lower classification hence if in doubt check requirements of a lower class sg 1604 2553 60825 1 IEC 2007 141 For Class 3R a time base of 0 25 s may be used for emission in the wavelength range 400 nm to 700 nm thus from Table 7 AEL 5 x 10 3 C W From Table 10 Cg 1 for direct viewing of a well collimated beam i e a lt 1 5 mrad therefore AEL 5 mW Since laser output power is 50 mW it exceeds the AEL for Class 3R but is less than the AEL for Class 3B therefore the laser would be classified as Class 3B Example B 3 2 A 12 mW CW diode laser A 900 nm without a collimating lens has a beam divergence of 0 5 rad and gave the following parameters for the measurement conditions specified in Table 11 What is its classification Assume the angular subtense of the source at a measurement distance of 100 mm is less than amin Condition 1 lt 20 uW through a 50 mm aperture stop 2 m from the laser diode chip Condition 2 1 4 mW through a 7 mm aperture stop 70 mm from the laser diode chip Condition 3 0 7 mW through a 7 mm aperture stop 100 mm from the laser diode chip Solution For such a diverg
33. 5 mrad Most laser sources have an angular subtense a less than amin and appear as an apparent point source small source when viewed from within the beam intra beam viewing Indeed a circular laser beam cannot be collimated to a divergence less than 1 5 mrad if it is an extended source thus any laser where a beam divergence in any plane of 1 5 mrad or less is specified cannot be treated as an extended source NOTE 2 For retinal thermal hazard evaluation 400 nm to 1 400 nm the AELs for extended sources vary directly with the angular subtense of the source For the retinal photochemical hazard evaluation 400 nm to 600 nm for exposures greater than 1 s the AELs do not vary directly with the angular subtense of the source Depending on the emission duration see 9 3 3b 1 a limiting angle of acceptance Yph of 11 mrad or more is used for measurement and the relation of the limiting acceptance angle Yph to the angular subtense a of the apparent source can influence the measured value NOTES For the default condition where Cg 1 a simplified Table 4 is provided for the AEL of Class 1 and 1M For sources subtending an angle less than or equal to amin the AEL and MPE are independent of the angular subtense of the apparent source a For classifying laser products at the most restrictive position where condition 1 applies see 9 3 3 the 7x magnification of the angular subtense of the apparent source may be applied to determine C
34. 6V Table 7 Accessible emission limits for Class 3R laser products and Cg 1 a b 0 Emission duration t Wave S length 10713 10711 1079 1077 8x1079 5 x 1075 1x1073 0 35 10 103 nm to to to to to to to to to to 10711 1079 1077 H 8x1075 5 x 1079 1 x 1073 0 35 10 103 8 x 104 180 to 302 5 1 5 x 1011 w m 2 150 J m 2 Photochemical hazard 4 0 x 10 6 Co J t gt T4 302 5 to 315 4 0 x 10 6 Co J 1 2x 105W Thermal hazard 4 x 1076 C4 J t lt T4 315 to 400 4 0 x 1076 Cy J 4 0 x 10 2 J 4 0 x 10 5 W 5 0 x 10 3 W t2 0 25 s 5 0 x 10 3 W 400 to 700 2 9 x 10 8 J 5 0 t0 75 J 1x10 6J t lt 0 255 3 5 x 10 3 10 75 J 700 to 1050 2 9 x 10 8 C4 J 5 0 t0 75 C4 J 1x 10 6 C4 J 3 5 x 1073 10 75 Cy J 2 0 x 10 3 C4 C7 W 1050 to 1 400 2 9 x 1077 07 52 t0 75 07 1x 10 5 C7 J 1 8 x 10 2 9 75 C7 1 400 to 1 500 4 x 106 W 4 x 1073J 2 2 x 10 2 10 25 J 5x10 2tJ 1 500 to 1 800 4 x 107 W 4 x 1072 J 9 x 1072 0 75 J 5 0 10 2W 1 800 10 2 600 4 x 106 W 4 x 10 3 J 2 2 x 10 2 0 25 J 5x10 2tJ 2 600 to 4 000 4x109W 4 x 1074 J 2 2 x 10 2 10 25 4 000 to 106 5 x 1011 W m 2 500 J m 2 2 8 x 104 0 25 J m 2 5 000 W m 2 a For correction factors and units see Table 10 b The AELs for emission durations less than 10713 s are set to be equal to the equivalent power or irradiance values of the AEL at 10713 s C For repetitively pulsed UV
35. 811 3 98 505 48 316 4 83 520 48 316 4 83 555 48 316 4 83 565 48 316 4 80 595 48 316 4 83 610 48 316 4 83 625 48 316 4 83 645 48 316 4 83 660 48 316 4 83 660 48 316 4 83 700 48 316 4 83 750 60 826 6 08 800 76 576 7 66 850 96 403 9 64 900 121 365 12 13 950 152 789 15 28 1 000 192 350 19 24 1 050 241 580 24 16 1 100 241 580 24 16 1 150 241 580 24 16 Figures in italics indicate retinal photochemical hazard limits E 3 Rationale Non 1604 2553 The radiance values are calculated using IEC ICNIRP MPE levels As MPEs are generally expressed in terms of radiant exposure J m or irradiance W m 2 it is necessary to convert the MPE values to radiance W m 2 sr The radiance values are then plotted as a function of wavelength For MPEs expressed as irradiance the following method to calculate radiance was used Radiance is defined as d o dO dA cos0 _93 1604 2553 60825 1 IEC 2007 183 where is the radiant power Q is a unit of solid angle and A is the source size MPEs are frequently expressed in terms of irradiance which is defined as en E 2 dA Substituting equation E 2 into equation E 1 yields radiance as a function of irradiance L A E 3 dQ cos0 We need to find the solid angle and viewing angle 0 Substituting the following equation for Q E 4 and assuming the worst case viewing angle where 0 0 the viewer is looking directly into t
36. Any parts of the housing or enclosure of a laser product including embedded laser products that can be removed or displaced for service and which would allow access to laser radiation in excess of the AEL assigned and are not interlocked see 4 3 shall be secured in such a way that removal or displacement of the parts requires the use of a tool or tools 4 2 3 Removable laser system If a laser system can be removed from its protective housing or enclosure and operated without modification the laser system shall comply with the manufacturing requirements of Clauses 4 and 5 that are appropriate to its class 4 3 Access panels and safety interlocks 4 3 1 A safety interlock shall be provided for access panels of protective housings when both of the following conditions are met 1604 2553 60825 1 IEC 2007 45 a the access panel is intended to be removed or displaced during maintenance or operation and b the removal of the panel gives access to laser radiation levels designated by X in Table 1 below Table 1 below indicates X the applicability of a safety interlock Table 1 Requirements for safety interlocking Accessible emission during or after removal of access panel Product class 1 1M 2 2M 3R 3B 4 Removal of the panel shall not result in emission through the opening in excess of the AEL for Class 1M or Class 2M as applicable according to the wavelength When a safety interlock is re
37. General energy sources such as electrical supply mains or batteries are not considered to constitute laser energy sources 3 44 laser hazard area see nominal ocular hazard area 3 61 _17 1604 2553 60825 1 IEC 2007 31 3 45 laser product any product or assembly of components which constitutes incorporates or is intended to incorporate a laser or laser system 3 46 laser radiation all electromagnetic radiation emitted by a laser product between 180 nm and 1 mm which is produced as a result of stimulated emission 3 47 laser safety officer one who is knowledgeable in the evaluation and control of laser hazards and has responsibility for oversight of the control of laser hazards 3 48 laser system laser in combination with an appropriate laser energy source with or without additional incorporated components 3 49 light emitting diode LED any semiconductor p n junction device which can be made to produce electromagnetic radiation by radiative recombination in the semiconductor in the wavelength range from 180 nm to 1 mm The optical radiation is produced primarily by the process of spontaneous emission although some stimulated emission may be present 3 50 limiting angle of acceptance for evaluating retinal photochemical hazards for evaluation of the retinal photochemical hazard a limiting measurement angle of acceptance y is specified The angle y is related to eye movements and is not d
38. IEC 2007 17 2 Normative references The following referenced documents are indispensable for the application of this document For dated references only the edition cited applies For undated references the latest edition of the referenced document including any amendments applies IEC 60050 845 1987 International Electrotechnical Vocabulary IEV Chapter 845 Lighting IEC 60601 2 22 Medical electrical equipment Part 2 Particular requirements for the safety of diagnostic and therapeutic laser equipment IEC 61010 1 Safety requirements for electrical equipment for measurement control and laboratory use Part 1 General requirements 3 Terms and definitions For the purposes of this document the definitions of IEC 60050 845 as well as the following apply NOTE For convenience here the definitions have been arranged in English alphabetical order Departures from IEC 60050 845 are intentional and are indicated In such cases reference is made between brackets to the definition of Part 845 of IEC 60050 with the mention modified 3 1 access panel part of the protective housing or enclosure which provides access to laser radiation when removed or displaced 3 2 accessible emission level of radiation determined at a position and with aperture stops when the AEL is given in units of Watts or Joules or limiting apertures when the AEL is given in units of W m or J m 2 as described in Clause 9 The acces
39. In short pulse lasers the high power density gives rise to explosive rupture of cells and damage by physical displacement purs IEC 422 07 Figure D 2 Diagram of laser induced damage in biological systems Thermal effects When sufficient radiant energy has been absorbed by a system its component molecules experience an increased vibration and this is an increase in heat content Most laser damage is due to the heating of the absorbing tissue or tissues This thermal damage is usually confined to a limited area extending to either side of the laser energy absorbing site and centred on the irradiating beam Cells within this area show burn characteristics and tissue damage primarily results from denaturation of protein As indicated above the occurrence of secondary damage mechanisms in laser impacts can be related to the time course of the tissue heating reaction which is directly related to the pulse duration see Figure D 2 and the period of cooling Thermochemical reactions occur during both the heating and cooling period giving rise to a spot size dependence of thermal injury If a CW or long pulse laser impulse is directed onto a tissue then because of conduction the area of the biological tissue experiencing a raised temperature is progressively increased This spreading thermal front results in an increasing damage zone as more and more cells are raised above their thermal tolerance Th
40. MPEs and irradiance averaging In this standard the maximum permissible exposure MPE values recommended by the International Commission on Non lonizing Radiation Protection ICNIRP have been adopted The irradiance averaging apertures measurement apertures recommended by the ICNIRP were adopted or an additional safety factor applied by IEC TC76 The determination and derivation of the AELs although generally based upon the MPEs necessitated a risk analysis and determination of reasonably foreseeable exposure conditions The choice of measurement aperture played a role in the derivation of AELs and reflects both biophysical and physiological factors In some cases considerations of risk assessment and simplification of expression played a role Table D 2 provides a summary of the factors assumed in the choice of measurement apertures In general the recommendations of ICNIRP were followed or added safety factors applied Table D 2 Explanation of measurement apertures applied to the MPEs Spectral band 2 Exposure nm duration Aperture diameter Comments and rationale mm for aperture diameter t Scatter in corneal epithelium and in stratum corneum leads to 1 mm assumption of no 180 to 400 t lt 3x 104s movement of exposed tissue for continuous exposure conditions is applied by IEC However ICNIRP recommends 3 5 mm for lengthy exposures due to eye movements 3 mm in derivation of Lateral motion of 3 mm diameter pupil 400 to 600 MP
41. The visible warning device s shall be located so that viewing does not require exposure to laser radiation in excess of the AEL for Class 1M and 2M 4 7 3 Each operational control and laser aperture that can be separated by 2 m or more from a radiation warning device shall itself be provided with a radiation warning device The warning device shall be clearly visible or audible to the person in the vicinity of the operational control or laser aperture 4 7 4 Where the laser emission may be distributed through more than one output aperture then a visible warning device shall clearly indicate the output aperture or apertures through which laser emission can occur in accordance with 4 7 2 4 8 Beam stop or attenuator Each Class 3B and Class 4 laser system shall incorporate one or more permanently attached means of attenuation e g beam stop attenuator switch The beam stop or attenuator shall be capable of preventing human access to laser radiation in excess of the AEL for Class 1M or Class 2M as applicable 4 9 Controls Each laser product shall have controls located so that adjustment and operation do not require exposure to laser radiation equivalent to Class 3R Class 3B or Class 4 4 10 Viewing optics Any viewing optics viewport or display screen incorporated in a laser product shall provide sufficient attenuation to prevent human access to laser radiation in excess of the AEL for Class 1M and for any shutter or variable atte
42. also 3 80 Examples are viewing of some diffused laser sources diffuse reflections and of some laser diode arrays 3 35 fail safe design consideration in which failure of a component does not increase the hazard In the failure mode the system is rendered inoperative or non hazardous 3 36 fail safe safety interlock interlock which in the failure mode does not defeat the purpose of the interlock for example an interlock which is positively driven into the OFF position as soon as a hinged cover begins to open or before a detachable cover is removed and which is positively held in the OFF position until the hinged cover is closed or the detachable cover is locked in the closed position 3 37 human access a ability of the human body to meet laser radiation emitted by the laser product i e radiation that can be intercepted outside of the protective housing or b ability of a cylindrical probe with a diameter of 100 mm and a length of up to 100 mm to intercept levels of radiation of Class 3B and below or C ability of a human hand or arm to intercept levels of radiation above the AEL of Class 3B 1604 2553 60825 1 IEC 2007 29 d also for levels of radiation within the housing that are equivalent to Class 3B or Class 4 ability of any part of the human body to meet hazardous laser radiation that can be reflected directly by any single introduced flat surface from the interior of the product through any
43. exposure to AEL above Classes 1 or 2 when adjustments are made Viewing optics 4 10 Not required Emission from all viewing systems must be below Class 1M AEL 400c O3l 1 8c809 68 6 7 091 Table F 2 continued Requirements Classification subclause Class 1 Class 1M Class 2 Class 2M Class 3R Class 3B Class 4 scanning T Scan failure shall not cause product to exceed its classification Class lapel ime Required wording Figures 1 and 2 and required wording Aperture Eei Not required Specified wording required Service access label 5 9 1 Not required Required as appropriate to the class of accessible radiation Override interlock label 5 9 2 Required under certain conditions as appropriate to the class of laser used Wavelength range label 5 10 and 5 11 Required for certain wavelength ranges User information 6 1 Operation manuals must contain instructions for safe use Additional requirements apply for Class 1M and Class 2M Purchasing and service information 6 2 Promotion brochures must specify product classification service manuals must contain safety information Medical products 7 2 Not required For the safety of medical laser products IEC 60601 2 22 applies NOTE This table is intended to provide a convenient summary of requirements See text of this standard for complete requi
44. exposure to light CIE spectral region Eye Skin Ultra violet C Erythema sunburn 180 nm to 280 nm Accelerated skin ageing process Ultra violet B Photokeratitis 280 nm to 315 nm Increased pigmentation Ultra violet A Photochemical cataract Pigment darkening 315 nm to 400 nm Photosensitive reactions Visible Photochemical and thermal retinal Skin b 400 nm to 780 nm injury I oun Infra red A Cataract retinal burn 780 nm to 1 400 nm Infra red B Aqueous flare cataract corneal 1 4 um to 3 0 um burn Skin Bunn Infra red C Corneal burn only 3 0 um to 1 mm 2 The spectral regions defined by the CIE are short hand notations useful in describing biological effects and may not agree perfectly with spectral breakpoints in the MPE Tables A 1 to A 3 If an increase of 2 x 105 is assumed a 50 W m 2 beam on the cornea becomes 1 x 107 W m 2 on the retina In this standard a 7 mm pupil is considered as a limiting aperture as this is a worst case condition and is derived from figures obtained from the young eye where pupillary diameters of this order have been measured An exception to the assumption of a 7 mm pupil was applied in the derivation of exposure limits to protect against photoretinitis whilst viewing bright visible 400 nm to 700 nm laser sources for periods in excess of 10 s In this latter situation a 3 mm pupil was assumed as a worst case condition however
45. for IEC 60825 1 suitable for use in a safety report EC TR 60825 8 Guidelines for the safe use of laser beams on humans EC TR 60825 9 Compilation of maximum permissible exposure to incoherent optical radiation broadband sources EC TR 60825 10 Application guidelines and explanatory notes to IEC 60825 1 EC TR 60825 13 Measurements for classification of laser products EC TR 60825 14 A user s guide IEC 62471 CIE S009 Photobiological safety of lamps and lamp systems 7 2 Medical laser products Each medical laser product shall comply with all of the applicable requirements for laser products of its class In addition any Class 3B or Class 4 medical laser product is subject to IEC 60601 2 22 7 3 Laser processing machines Laser processing machines shall comply with applicable requirements for laser products of their class In addition laser processing machines may be subject to ISO IEC 11553 1 7 4 Electric toys Electric toys that are laser products shall comply with applicable requirements for laser products of their class In addition these products are subject to IEC 62115 7 5 Consumer electronic products Consumer electronic products that are laser products shall comply with applicable requirements for laser products of their class In addition these products may be subject to one of the following standards IEC 60950 IT equipment IEC 60065 AV equipment 8 Classification 8 1 Introducti
46. for wavelengths from 400 nm to 106 nm is determined by using the most restrictive of requirements a b and c Requirement c applies only to the retinal thermal limits and not to the retinal photochemical limits The MPE for ocular exposure for wavelengths less than 400 nm and the MPE for skin exposure is limited by the most restrictive of requirements a and b a The exposure from any single pulse within a pulse train does not exceed the MPE for a single pulse b The average exposure for a pulse train of exposure duration 7 does not exceed the MPE given in Tables A 1 A 2 and A 3 for a single pulse of exposure duration T C 1 For constant pulse energy and pulse duration values The exposure per pulse does not exceed the MPE for a single pulse multiplied by the correction factor Cs Cs is only applicable to individual pulse duration shorter than 0 25 s MPE p train MPEsingle x Cs NOTE Cs is only applicable to pulse durations shorter than 0 25 s where MPEgingle is the MPE for a single pulse MPEg p train is the MPE for any single pulse in the pulse train C5 N 1 4 N is the effective number of pulses in the pulse train within the assessed exposure duration when pulses occur within 7 see Table 3 N is less than the actual number of pulses see below The maximum exposure duration that needs to be considered for the assessment for wavelengths between 400 nm and 1 400 nm is 7 see Table 10 or the applicable time b
47. in the design or function of the laser product Every possible emission duration within the time base must be considered when determining the classification of a product This means that the emission level of a single pulse must be compared to the AEL applicable to the duration of the pulse etc It is not sufficient to only average the emission level for the duration of the classification time base or to merely perform the evaluation for the value of the time base without considering shorter emission durations NOTE Fora multi wavelength emission laser product with emission in the visible and in the non visible part of the spectrum where the emission is assessed as additive see Table 2 and where the visible part on its own would be classified as Class 2 or 2M or 3R and the non visible part on its own would be classified as Class 1 or Class 1M the time base for the assessment of the added emission may be 0 25 s even for the non visible part Repetitively pulsed or modulated lasers The following methods shall be used to determine the class of the laser product to be applied to repetitive pulsed or modulated emissions 40 1604 2553 60825 1 IEC 2007 77 For all wavelengths requirements 1 and 2 shall be assessed In addition for wavelengths from 400 nm to 108 nm requirement 3 shall also be assessed for comparison with thermal limits Requirement 3 does not need to be assessed for comparison with photochemica
48. laser output less than AEL for chosen class for Condition 1 AND Condition 2 Do you need to check if product could satisfy AEL of a lower class Do you need to check if laser product could be Class 1M or 2M Is laser output measured with Condition 1 OR Condition 2 less than AEL for Class 1 or Class 2 AND less than AEL for Class 3B for both Conditions Determine AEL for chosen class Measure laser output as per Conditions 1 and 2 see Table 11 Finish laser is chosen Class Laser is not Class 1M or Class 2M IEC 417 07 Figure B 2 Flowchart guide for the classification of Class 1M and Class 2M laser products 70 60825 1 IEC 2007 137 1604 2553 IEC 418 07 i 2 1 1 1 3 gt 10 0 s lt t lt 10 s o L S E B A t L S T A tc 10 E 10 B 10 lt 1 lt 10 5 m 10 f 1 i i Lob 1 f 200 205 300 320 340 360 380 400 Wavelength nm Figure B 3 AEL for Class 1 ultra violet laser products for selected emission durations from 10 9 s to 103 s 5 10 315 nm 400 nm gt o E E c E E L 312 5 nm S L ge fe 10 L 310 nm L 307 5 nm 10 E 305 nm 180 nm 302 5 nm 10 pannil ft inl 1 1 1 Lr ul paal o anl 1 1 paal oal p pL LLL 9 io 40 4g 10 10 10 10 10 10 10 10 10 Emission d
49. leave it unchanged 3 82 thermal hazard limit either an MPE or AEL which was derived to protect persons against adverse thermal effects as opposed to photochemical injury 3 83 time base emission duration to be considered for classification of laser products see 8 3 e 3 84 tool denotes a screwdriver hexagonal key or other object which may be used to operate a screw or similar fixing means 3 85 transmittance ratio of the transmitted radiant flux to the incident flux in the given conditions IEV 845 04 59 modified Symbol SI unit 1 3 86 transmittance optical density logarithm to base ten of the reciprocal of the transmittance IEV 845 04 66 D logiot Symbol D 3 87 visible radiation light any optical radiation capable of causing a visual sensation directly IEV 845 01 03 NOTE In this Part 1 this is taken to mean electromagnetic radiation for which the wavelengths of the mono chromatic components lie between 400 nm and 700 nm 3 88 workpiece an object intended for processing by laser radiation 23 1604 2553 60825 1 IEC 2007 48 4 Engineering specifications 4 1 General remarks Laser products require certain built in safety features depending on the class to which they have been assigned by the manufacturer The requirements for these are given in 4 2 to 4 12 The manufacturer shall ensure that the personnel responsible for the classification of
50. location of the retinal hazard the real or virtual object that forms the smallest possible retinal image considering the accommodation range of the human eye NOTE 1 The accommodation range of the eye is assumed to be variable from 100 mm to infinity The location of the apparent source for a given viewing position in the beam is that location to which the eye accommodates to produce the most hazardous retinal irradiance condition NOTE 2 This definition is used to determine for a given evaluation position the location of the apparent origin of laser radiation in the wavelength range of 400 nm to 1 400 nm In the limit of vanishing divergence i e in the case of a well collimated beam the location of the apparent source goes to infinity 12 1604 2553 60825 1 IEC 2007 21 3 11 beam laser radiation that may be characterized by direction divergence diameter or scan speci fications Scattered radiation from a non specular reflection is not considered to be a beam 3 12 beam attenuator device which reduces the laser radiation to or below a specified level 3 13 beam diameter beam width the beam diameter d at a position in space is the diameter of the smallest circle which contains of the total laser power or energy For the purpose of this standard dg3 is used NOTE 1 ln the case of a Gaussian beam d corresponds to the point where the irradiance radiant exposure falls to 1 e of its centr
51. opening in its protective housing NOTE For laser products that provide walk in access it is necessary to consider radiation both inside and outside of the protective housing for the determination of human access Human access inside the housing can be prevented by engineering controls such as automatic detection systems 3 38 integrated radiance integral of the radiance over a given exposure duration expressed as radiant energy per unit area of a radiating surface per unit solid angle of emission usually expressed in J m sr 3 39 intrabeam viewing all viewing conditions whereby the eye is exposed to the direct or specularly reflected laser beam in contrast to viewing of for example diffuse reflections 3 40 irradiance quotient of the radiant flux d incident on an element of a surface by the area dA of that element dA Symbol E SI unit watt per square metre W m 2 3 41 laser any device which can be made to produce or amplify electromagnetic radiation in the wavelength range from 180 nm to 1 mm primarily by the process of controlled stimulated emission IEV 845 04 39 modified 3 42 laser controlled area area where the occupancy and activity of those within is subject to control and supervision for the purpose of protection from radiation hazards 3 43 laser energy source any device intended for use in conjunction with a laser to supply energy for the excitation of electrons ions or molecules
52. than 10 13 s are set to be equal to the equivalent power or irradiance values of the AEL at 10 13 s c In the wavelength range between 450 nm and 500 nm dual limits apply and a product s emission must not exceed either limit applicable to the class assigned 4002 0431 L S82809 6 7 091 Vere LY Table 5 Accessible emission limits for Class 1 laser products in the wavelength range from 400 nm to 1 400 nm retinal hazard region extended sources 9 P c d e Emission duration t Wave S length 10 13 10 11 10 9 1 8 x 10 5 5 x 10 5 10 102 104 X to to to to to to to to nm 10711 10 9 1 8 x 10 5 5 x 10 5 10 102 104 8 x 104 400 nm to 600 nm Retinal photochemical hazard 4 3 9 x 10 3 Cg J 3 9 x 10 5 C3 W 3 9 x 10 5 C3 W using using using Yph 11 mrad Yph 1 1 10 5 mrad Yph 110 mrad 400 to 700 5 8x 10 Cg J 1 0 9 75 Cg J 2 x 10 7 Cg J 7 x 10 10 75 Ce AND 400 nm to 700 nm Retinal thermal hazard 7 x 10 Cg 72025 W t lt T2 t gt T2 7 x 10 10 75 Cg J 700 to 1 050 5 8 x 10 9 C4 Cg J 1 0 10 75 C4 Cg J 2 x 1077C4 Cg J 7 x 10 075 C4 Cg J 1 050 to 1 400 5 8 x 10 8 Cg C7 10 4 t 975 Cg C7 2x 10 6 Cg C7 J 3 5 x 10 975 Cg C7 J 7 x 10 C4 Cg C T9 025 W t lt To t T2 7 x 10 0 75 C4 Cg C7 J NOTE Laser products that meet the requirements for classification as Class 1 by satisfying measurement conditions
53. the requirements for safety interlocks labels and information for the user The above tests shall be made under each and every reasonably foreseeable single fault condition However if the emission is reduced to a level below the AEL by automatic reduction in a duration within which it is not reasonably foreseeable to have human access then such faults need not be considered NOTE 1 Automatic reduction includes physical limitation of the emission such as component or system failure to a safe condition It does not include manual reduction or termination of the emission NOTE 2 For example a scanning safeguard may not react fast enough to prevent emission above the AEL during the fault condition however this might be acceptable for products where exposure of people is unlikely NOTES Acceptable modes of analysis of the probability and risk regarding failures are FMEA failure mode and effect analysis etc see for instance IEC 61508 Probability analysis may be used to assist in determining reasonably foreseeable single fault conditions NOTE 4 Classification is determined during operation and restrictions on maintenance are then dependent upon the classification of the product 42 1604 2553 60825 1 IEC 2007 81 When assessing the suitability of protective housings for the prevention of human access to a level of energy that is equivalent to Class 4 single fault events for all reasonably foreseeable changes o
54. the thermal ocular hazard MPEs are increased by the factor Cg provided that the angular subtense of the source measured at the viewer s eye is greater than amin where amin is equal to 1 5 mrad The correction factor Cg is given by Cg 1 for a lt Qmin Ce for QOmin lt Q lt Qmax for a gt Omax 65 1604 2553 60825 1 IEC 2007 B 1 Symbol a AEL Omin C1 C2 C7 PRF Ti To B 2 Unit m W J W m 2 or J m rad rad rad o o oc a 127 Annex B informative Examples of calculations Symbols used in the examples of this annex Definition Diameter of the emergent laser beam Accessible emission limit The angle subtended by an apparent source or a diffuse reflection as viewed at a point in space Minimum angle subtended by a source for which the extended source criterion applies Correction factors see Table 10 Pulse repetition frequency Radiant exposure Irradiance at a specified distance r from the apparent source Emergent beam radiant exposure Irradiance at zero distance from the apparent source Wavelength of laser radiation Number of pulses contained within an exposure duration Total radiant power radiant flux of a CW laser or average radiant power of a repetitively pulsed laser Radiant power within a pulse of a pulsed laser Divergence angle of an emergent laser beam The numerical constant 3 142 Total radiant energy of a pulsed
55. this simplified evaluation it is not necessary to determine the angular subtense of the apparent source as Cg see Table 10 is set equal to unity b For radiation with wavelengths in the retinal hazard region of 400 nm to 1 400 nm when the AEL is increased by a parameter Cg with values greater than 1 for extended sources it is necessary to assess the class of the product i e to compare the accessible emission value with the corresponding AEL at the most restrictive position in the beam This second method is more complicated than the default evaluation in a above but for extended sources it can allow higher accessible emission values NOTE The most restrictive position is in many cases not at a distance of 100 mm to the reference point used for the basic evaluation but further away Determination of the angular subtense of the apparent source at a distance of 100 mm from the reference point would in those cases result in an AEL which exceeds the AEL determined at the most restrictive position If the simplified default evaluation results in the desired classification there is no need to perform the complete evaluation for extended sources see 9 3 2 even though the actual source might be extended and the actual factor Cg might be greater than 1 and the most restrictive position is different from the position as given in Table 11 NOTE f the source is a bare laser diode or if it emits a well collimated laser beam the simplified
56. to a class when the accessible laser radiation measured under the conditions appropriate to that class exceeds the AELs of all lower classes for at least one wavelength but does not exceed the AEL for the class assigned for any wavelength 38 1604 2553 60825 1 IEC 2007 73 Table 2 Additivity of effects on eye and skin of radiation of different spectral regions Spectral UV C and UV B UV A Visible and IR A IR B and IR C regiona 180 nm to 315 nm 315 nm to 400 nm 400 nm to 1 400 nm 1 400 nm to 109 nm 180 nm to 315 nm UV C and UV B o UV A 0 0 315 10 400 Visible and IR A ob 400 nm to S 1 400 nm 1 IR B and IR C o 400 nm to 108 nm s Eye Skin o For definitions of spectral regions see Table D 1 Where AELs and ocular MPEs are being evaluated for time bases or exposure durations of 1 s or longer then the additive photochemical effects 400 nm to 600 nm and the additive thermal effects 400 nm to 1 400 nm shall be assessed independently and the most restrictive value used c d Radiation from extended sources The ocular hazard from laser sources in the wavelength range from 400 nm to 1 400 nm is dependent upon the angular subtense of the apparent source a NOTE 1 A source is considered an extended source when the angular subtense of the source is greater than Omin Where amin 1
57. to that subtended by the moon If this region is damaged the decrement may appear initially as a blurred white spot obscuring the central area of vision however within two or more weeks it may change to a black spot Ultimately the victim may cease to be aware of this blind spot scotoma during normal vision However it can be revealed immediately on looking at an empty visual scene such as a blank sheet of white paper Peripheral lesions will only be registered subjectively when gross retinal damage has occurred Small peripheral lesions will pass unnoticed and may not even be detected during a systematic eye examination In the wavelength range from 400 nm to 1 400 nm the greatest hazard is retinal damage The cornea aqueous humour lens and vitreous humor are transparent for radiation of these wavelengths In the case of a well collimated beam the hazard is virtually independent of the distance between the source of radiation and the eye because the retinal image is assumed to be a diffraction limited spot of around 10 um to 20 um diameter In this case assuming thermal equilibrium the retinal zone of hazard is determined by the limiting angular subtense amin Which generally corresponds to retinal spot of approximately 25 um in diameter In the case of an extended source the hazard varies with the viewing distance between the source and the eye because whilst the instantaneous retinal irradiance only depends on the source s radiance an
58. 0 x 500 025 J AELs p train 3 57 x 103 J The most restrictive of the three values is AEL 51 1 x 103 J The laser energy per pulse Q is calculated from the relationship Q peak power x pulse duration Q 104 x 10 8 0 01 J Since the accessible emission energy per pulse exceeds AEL the AEL for Class 3B and therefore must be Class 4 s p the laser product exceeds J5 1604 2553 60825 1 IEC 2007 147 Annex C informative Description of the classes and potentially associated hazards C 0 General This annex contains a description of the classes as well as potentially associated hazards The annex is intended as a guide for the manufacturer in their task of describing the hazards associated with the product This annex also points out limitations of the classification scheme i e situations where the generally associated meaning of the class is not appropriate C 1 Introduction Classification was developed to aid the user in hazard evaluation of the laser and to determine necessary user control measures Laser classification relates to the potential hazard of the accessible laser radiation in respect to skin or eye damage and does not relate to other potential hazards such as electrical mechanical or chemical hazards or hazards from secondary optical radiation The intent of classification is to recognize the increased risk of injury with increasing powers accessible above the base line Cl
59. 1 Safety of machinery Electrical equipment of machines Part 1 General requirements IEC 60825 2 Safety of laser products Part 2 Safety of optical fibre communication systems OFCS IEC TR 60825 3 Safety of laser products Part 3 Guidance for laser displays and shows IEC 60825 4 Safety of laser products Part 4 Laser guards IEC TR 60825 5 Safety of laser products Part 5 Manufacturer s checklist for IEC 60825 1 IEC TR 60825 8 Safety of laser products Part 8 Guidelines for the safe use of laser beams on humans IEC TR 60825 9 Safety of laser products Part 9 Compilation of maximum permissible exposure to incoherent optical radiation IEC TR 60825 10 Safety of laser products Part 10 Application guidelines and explanatory notes to IEC 60825 1 IEC 60825 12 Safety of laser products Part 12 Safety of free space optical communication systems used for transmission of information IEC TR 60825 13 Safety of laser products Part 13 Measurements for classification of laser products IEC TR 60825 14 Safety of laser products Part 14 A user s guide IEC 60950 all parts Information technology equipment Safety IEC 61040 Power and energy measuring detectors instruments and equipment for laser radiation IEC 61508 all parts Functional safety of electrical electronic programmable electronic safety related systems 01 1604 2553 60825 1 IEC 2007 199 IEC 62
60. 1 and 2 may be hazardous when used with viewing optics having greater than x7 magnification or objective diameters greater than those specified in Table 11 a For correction factors and units see Table 10 b The AELs for emission duration less than 10 1 s are set to be equal to the equivalent power or irradiance values of the AEL at 10 13 s c In the wavelength range between 400 nm and 600 nm dual limits apply and a product s emission shall not exceed either limit applicable to the class assigned 4 The angle Ypn is the limiting measurement angle of acceptance e f exposure times between 1 s and 10 s are used for wavelengths between 400 nm and 484 nm and for apparent source sizes between 1 5 mrad and 82 mrad the dual photochemical hazard limit of 3 9 x 10 3 C 3 Jis extended to 1 s 400c O3l L Sc809 6 7 091 UCN 1604 2553 60825 1 IEC 2007 91 Table 6 Accessible emission limits for Class 2 and Class 2M laser products Wavelength 2 Emission duration t Class 2 AEL nm S t lt 0 25 Same as Class 1 AEL 400 to 700 3 1 gt 0 25 Cg x 1078 W NOTE Laser products that meet the requirements for classification as Class 2 by satisfying measurement conditions 1 and 2 may be hazardous when used with viewing optics having greater than x7 magnification or aperture diameters greater than those specified in Table 11 a For correction factor and units see Table 10 adis
61. 115 Electric toys Safety IEC 62471 2006 CIE S009 2002 Photobiological safety of lamps and lamp systems ISO 1000 SI units and recommendations for the use of their multiples and of certain other units ISO 11146 1 Lasers and laser related equipment Test methods for laser beam widths divergence angles and beam propagation ratios Part 1 Stigmatic and simple astigmatic beams IEC ISO 11553 1 Safety of machinery Laser processing machines Part 1 General safety requirements ISO 12100 1 Safety of machinery Basic concepts general principles for design Part 1 Basic terminology methodology ISO 12100 2 Safety of machinery Basic concepts general principles for design Part 2 Technical principles ISO 13694 Optics and optical instruments Lasers and laser related equipment Test methods for laser beam power energy density distribution 102
62. 8 2 and 8 3 e 13 1604 2553 60825 1 IEC 2007 23 NOTE 1 See also the limitations of the classification scheme in Annex C NOTE 2 As tests for the determination of the classification of the product are limited to tests during operation it may be the case for embedded laser products that depending on the product radiation above the AEL of Class 1 can become accessible during maintenance when interlocks of access panels are overridden 3 19 Class 1M laser product any laser product in the wavelength range from 302 5 nm to 4 000 nm which during operation does not permit human access to accessible laser radiation in excess of the accessible emission limits of Class 1 for applicable wavelengths and emission durations see 8 3e where the level of radiation is measured according to 9 2 g NOTE 1 See also the limitations of the Classification scheme in Annex 6 NOTE 2 Since the evaluation is with a smaller measurement aperture or at a greater distance from the apparent source than those used for Class 1 laser products the output of a Class 1M laser product is therefore potentially hazardous when viewed using an optical instrument see 8 2 NOTES As tests for the determination of the classification of the product are limited to tests during operation it may be the case for embedded laser products that depending on the product radiation above the AEL of Class 1M can become accessible during maintenance when inter
63. Class 4 laser system shall incorporate a manual reset to enable resumption of accessible Class 4 laser radiation emission after interruption of emission caused by the use of the remote interlock connector or an interruption of longer than 5 s of electrical mains power NOTE Manufacturers may include a second interlock connector that does not require active action for starting emission but it is not required for a product to have two connectors 25 1604 2553 60825 1 IEC 2007 47 4 6 Key control Each Class 3B and Class 4 laser system shall incorporate a key operated master control The key shall be removable and the laser radiation shall not be accessible when the key is removed NOTE n this Part 1 the term key includes any other control devices such as magnetic cards cipher combinations computer passwords etc 4 7 Laser radiation emission warning 4 7 1 Each Class 3H laser system in the wavelength range below 400 nm and above 700 nm and each Class 3B and Class 4 laser system shall satisfy the following 4 7 2 A warning device shall give an audible or visible signal when the laser system is switched on or if any capacitor banks of a pulsed laser are being charged or have not positively discharged The warning device shall be fail safe or redundant Any visible warning device shall be clearly visible through protective eyewear specifically designed for the wavelength s of the emitted laser radiation
64. D NOTE Simplified calculations may significantly underestimate the NOHD For example when the laser aperture is inside of a large Raleigh range when there is an external beam waist or when the beam profile is such that the power that passes through an aperture is underestimated when a Gaussian beam profile is assumed In such cases it is usually advantageous to determine the NOHD by measurements Maximum permissible exposure values as contained in this document are adopted from exposure limit values published by International Commission on Non lonizing Radiation Protection MPE values are set below known hazard levels and are based on the best available information from experimental studies The MPE values should be used as guides in the control of exposures and should not be regarded as precisely defined dividing lines between safe and dangerous levels In any case exposure to laser radiation should be as low as possible Exposures from several wavelengths should be assumed to have an additive effect on a pro portional basis of spectral effectiveness according to the MPEs of Tables A 1 A 2 and A 3 provided that the spectral regions are shown as additive by the symbols o for ocular and s for skin exposure in the matrix of Table 2 Where the wavelengths radiated are not shown as additive the hazards should be assessed separately 59 09 Table A 1 Maximum permissible exposure MPE for Cg 1 at the cornea for exposure to l
65. E but 7 mm used in space to produce 7 mm aperture photochemical averaging for CW exposures applicable for photochemical injury mechanism 400 to 1400 All t 7 mm Diameter of dilated pupil and lateral motion thermal in CW exposures X gt 1400 1 lt 0 35 5 1mm Thermal diffusion in stratum corneum and epithelial tissues x gt 1 400 0 35s lt t lt 10s 1 5 x t3 8 mm Greater thermal diffusion and movement of t gt 10s 3 5 mm target tissue relative to beam after 0 35 s Aperture to be greater than diffraction limit 105 lt lt 106 All t 11 mm i e approximately 10x for accurate measurements for measurements 1604 2553 60825 1 IEC 2007 177 D 4 Reference documents HENDERSON R and SCHULMEISTER K Laser Safety Institute of Physics Publishing Bristol 2003 International Commission on Non lonizing Radiation Protection ICNIRP Guidelines on limits of exposure to laser radiation of wavelengths between 180 nm and 1 000 um Health Phys 71 5 804 819 1996 International Commission on Non lonizing Radiation Protection ICNIRP Revision of guidelines on limits of exposure to laser radiation of wavelengths between 400 nm and 1 4 um Health Phys 79 4 431 440 2000 NESS J ZWICK H A STUCK B A LUND D J MOLCHANY J A and SLINEY D H Hetinal image motion during deliberate fixation implications to laser safety for long duration viewing Health Phys 78 2 131 142 ROACH W P JOHNSON P E
66. EC 2007 149 The wavelength region for Class 1M lasers is restricted to the spectral region where most glass optical materials used in optical instruments can significantly transmit i e between 302 5 nm and 4 000 nm Intrabeam viewing of Class 1M laser products which emit visible radiant energy may still produce dazzling visual effects particularly in low ambient light Class 2 Laser products that emit visible radiation in the wavelength range from 400 nm to 700 nm that are safe for momentary exposures but can be hazardous for deliberate staring into the beam The time base of 0 25 s is inherent in the definition of the class and presumption is that there is very low risk of injury for momentary exposures that are somewhat longer The following factors contribute to precluding injury under reasonably foreseeable conditions unintentional exposures would rarely reflect worst case conditions for example of beam alignment with the pupil for a stabilised head worst case accommodation the inherent safety margin in the MPE upon which the AEL is based natural aversion behaviour for exposure to bright light For Class 2 in contrast to Class 2M the use of optical instruments does not increase the risk of ocular injury However dazzle flash blindness and afterimages may be caused by a beam from a Class 2 laser product particularly under low ambient light conditions This may have indirect general safety implications result
67. Requirements for safety interlocking 0 ccccceeeeneee eee eeee ceed eeaeeeaaeeea essa essa eeseeeees 45 Table 2 Additivity of effects on eye and skin of radiation of different spectral regions 73 Table 3 Times below which pulse groups are summed 0 cece eee ee ence eee e He 79 Table 4 Accessible emission limits for Class 1 and Class 1M laser products GUN Cpe 87 Table 5 Accessible emission limits for Class 1 laser products in the wavelength range from 400 nm to 1 400 nm retinal hazard region extended sources 89 Table 6 Accessible emission limits for Class 2 and Class 2M laser products 91 Table 7 Accessible emission limits for Class 3R laser products and Cg 1 93 Table 8 Accessible emission limits for Class 3R laser products in the wavelength range from 400 nm to 1 400 nm retinal hazard region extended sources 95 Table 9 Accessible emission limits for Class 3B laser products 2 2000 97 Table 10 Correction factors and breakpoints for use in AEL and MPE evaluations 99 Table 11 Measurement aperture diameters and measurement distances for the default simplified CvalUatiOn cece eee e eect ee cee tetera eee menm nennen nennen nnne nnne 103 Table 12 Reference Points oer
68. a 7 mm irradiance averaging aperture for measurement was still considered appropriate due to physiological movements of the pupil in space Hence AELs for durations greater than 10 s are still derived for a 7 mm aperture If an intense beam of laser light is brought to a focus on the retina only a small fraction of the light up to 5 96 will be absorbed by the visual pigments in the rods and cones Most of the light will be absorbed by the pigment called melanin contained in the pigment epithelium In the macular region some energy in the 400 nm to 500 nm range will be absorbed by the yellow macular pigment The absorbed energy will cause local heating and will burn both the pigment epithelium and the adjacent light sensitive rods and cones This burn or lesion may result in a loss of vision Photochemical injuries although non thermal are also localized in the pigment epithelium 86 1604 2553 60825 1 IEC 2007 169 Depending on the magnitude of the exposure such a loss of vision may or may not be permanent A visual decrement will usually be noted subjectively by an exposed individual only when the central or foveal region of the macula is involved The fovea the pit in the centre of the macula is the most important part of the retina as it is responsible for sharpest vision It is the portion of the retina that is used to look right at something This visual angle subtended by the fovea is approximately equal
69. al peak value NOTE2 The second moment diameter definition as defined in ISO 11146 1 is not used for beam profiles with central high irradiance peaks and a low level background such as produced by unstable resonators in the far field the power that passes through an aperture can be significantly underestimated when using the 2nd moment and calculating the power with the assumption of a Gaussian beam profile 3 14 beam divergence far field plane angle of the cone defined by the beam diameter If the beam diameters see 3 13 at two points separated by a distance rare dg3 and d gs the divergence is given by 0 2 arctan 2r SI unit radian NOTE The second moment divergence definition ISO 11146 1 is not used for beam profiles with central high irradiance peaks and a low level background such as produced by unstable resonators in the far field or beam profiles that show diffraction patterns caused by apertures 3 15 beam expander combination of optical elements which will increase the diameter of a laser beam 3 16 beam path component optical component which lies on a defined beam path e g a beam steering mirror or a focusing lens 3 17 beam stop device which terminates a laser beam path 3 18 Class 1 laser product any laser product which during operation does not permit human access to accessible laser radiation in excess of the accessible emission limits of Class 1 for applicable wavelengths and emission durations see
70. ased on assumptions and evaluations of the likelihood of exposure with certain types of optical instruments For example a large diameter collimated beam intercepted by a large telescope might be hazardous even for a Class 1 laser product However the probability of such an accidental ocular exposure is usually very small due to the small field of view of the telescope Another situation that might need to be considered is where a product is placed into a condition which is not required to be considered for classification but from which hazardous radiation might nevertheless become accessible For instance even though it is not provided by the manufacturer of the product as an accessory a divergent beam from a Class 1M or Class 2M product could be transformed into a collimated beam with a potentially large hazard distance by attaching a collimating lens to the product However this would be considered as changing the product and the person carrying out that change should re classify the product 80 1604 2553 60825 1 IEC 2007 157 Nevertheless the manufacturer should be aware of the limitations so that it is possible to include warnings in the user manual for products Specific examples of such potential limitations are given below note that these limitations are only potential because it depends on the type of product if the limitations apply or not Large diameter collimated beam Class 1 Class 2 or Class 3R la
71. aser radiation gt Exposure time t Wave length A 10 13 10 11 10 9 10 7 1 8 x 10 5 5 x 10 5 1x 10 3 10 102 103 nm to to to to to to to to to to 10 11 10 9 10 7 1 8 x 10 5 5 x 10 5 1 x 10 3 10 102 103 3 x 104 180 to 302 5 30 J m 2 Photochemical hazard d t gt T C J m 2 10 W m 2 2 m 2 302 5 to 315 3 x 1010 Wem Thermal hazardd 6 1 lt T4 C Jm 315 to 400 J m 2 104 J m 2 400 to 450 100 J m 2 100 C4 J m 2 A 45010 500 4 5 x 10 4 J m 2 2 7 x 104 19 75 J m 5 x 10 3 J m 18 075 J m and LE 10 W m 2 500 to 700 10 W m 2 700 to 1 050 1 5 x 10 4 C4 J m 2 2 7 x 104 0 75 C J m 2 5 x 10 3 C J m 2 18 9 75 C J m 2 ma 1 050 to 1 400 1 5 x 10 3 C J m 2 7 x 105 0 75 C J m 5 x 10 2 C J m 90 19 75 C J m 2 d 1400 to 1 500 1012 W m 2 103 J m 2 5 600 0 25 J m 2 1 500 to 1 800 1013 W m 2 104 J m 2 1 000 W m 1 800 to 2 600 1012 W m 2 103 J m 2 5 600 t 0 25 m 2 2 600 to 106 1011 W m 2 100 J m 2 5 600 10 25 J m For correction factors and units see Table 10 b The MPEs for exposure durations below 10 s and for wavelengths less than 400 nm and greater than 1 400 nm have been derived by calculating the equivalent irradiance from the radiant exposure limits at 10 9 s The MPEs for exposure durations below 10 13 s are set to be equal to the equivalent irradiance values of th
72. asis whichever is shorter For wavelengths greater than 1 400 nm the maximum duration to be considered is 10 s If multiple pulses appear within the period of T see Table 3 they are counted as a single pulse to determine N and the radiant exposure of the individual pulses are added to be compared to the MPE of 71 63 1604 2553 60825 1 IEC 2007 123 2 For varying pulse widths or varying pulse durations In cases of varying pulse widths or pulse intervals the total on time pulse TOTP method is used The MPE is determined by the duration of the TOTP which is the sum of all pulse durations within the exposure duration or To whichever is smaller Pulses with durations less than T are assigned pulse durations of T If two or more pulses occur within a duration of 7 these pulse groups are assigned pulse durations of T For comparison with the MPE for the corresponding duration all individual pulse radiant exposures are added A 4 Measurement conditions A 4 1 General In order to evaluate the actual exposure the following measurement conditions should be applied A 4 2 Limiting aperture The values of radiant exposure or irradiance to be compared to the respective MPE are averaged over a circular aperture stop according to the limiting apertures of Table A 4 For ocular exposure in the wavelength range from 400 nm to 1 400 nm a minimum measurement distance of 100 mm is used A 4 3 Angle of a
73. ass 1 condition and most accurately describes the risk from potential exposures at short distances from the laser The hazard zone can differ greatly for different lasers within one class The potential hazard could be greatly reduced by additional user protective measures including additional engineering controls such as enclosures C 2 Description of classes Class 1 Laser products that are safe during use including long term direct intrabeam viewing even when exposure occurs while using optical viewing instruments eye loupes or binoculars Class 1 also includes high power lasers that are fully enclosed so that no potentially hazardous radiation is accessible during use embedded laser product Intrabeam viewing of Class 1 laser products which emit visible radiant energy may still produce dazzling visual effects particularly in low ambient light Class 1M Laser products that are safe including long term direct intrabeam viewing for the naked eye unaided eye The MPE can be exceeded and eye injury may occur following exposure with one of the two categories of optical viewing instruments eye loupes or binoculars under the following conditions a for diverging beams if the user places optical components within 100 mm from the source to concentrate collimate the beam or b for a collimated beam with a diameter larger than the measurement diameter specified for condition 3 see Table 11 1604 2553 60825 1 I
74. ass 1 except may be hazardous if user employs optics Low power eye protection normally afforded by aversion responses As for Class 2 except may be more hazardous if user employs optics Direct intrabeam viewing may be hazardous Direct intrabeam viewing normally hazardous High power diffuse reflections may be hazardous Protective housing 4 2 Required for each laser product limits access necessary for performance of functions of the products Safety interlock in protective housing Designed to prevent removal of the panel until accessible emission values are below that for Class 3R Designed to prevent removal of the panel until accessible emission values are below that for 4 3 Class 3B or 3R for some products Remote Interlock Not required Permits easy addition of external interlock 4 4 in laser installation Manual Reset Not required Requires manual reset if power interrupted or remote interlock is 4 5 actuated Key EE Not required Laser inoperative when key is removed Emission warning device 4 7 Not required Gives audible or visible warning when laser is switched on or if capacitor bank of pulsed laser is being charged For Class 3R only applies if invisible radiation is emitted Attenuator 4 Not required Gives means to temporarily block beam Location controls Not required Controls so located that there is no danger of
75. ation Equivalent tests or procedures are acceptable Optical amplifiers shall be classified using the maximum accessible total output power or energy which may include maximum rated input power or energy NOTE ln those cases where there is no clear output power or energy limit the maximum power or energy added by the amplifier plus the necessary input signal power or energy to achieve that condition should be used 9 2 Measurement of laser radiation Measurement of laser radiation levels may be necessary to classify a laser product in accordance with 9 1 Measurements are unnecessary when the physical characteristics and limitations of the laser source place the laser product or laser installation clearly in a particular class Measurements shall be made under the following conditions and procedures a Conditions and procedures which maximize the accessible emission levels including start up stabilized emission and shut down of the laser product b With all controls and settings listed in the operation maintenance and service instructions adjusted in combination to result in the maximum accessible level of radiation Measurements are also required with the use of accessories that may increase the radiation hazard for example collimating optics which are supplied or offered by the manufacturer for use with the product NOTE This includes any configuration of the product which it is possible to attain without using tools or defeatin
76. ay tracing a Aperture diameters For condition 1 and condition 3 for the determination of the accessible emission as well as the angular subtense of the apparent source both of which are to be determined at the most restrictive position in the beam the aperture diameters as specified in Table 11 shall be used see Figures 3 and 4 Angular subtense Circular Circular of the apparent aperture stop field stop Angle source of acceptance Active area of the detector Apparent source Measuring distance r lt Image distance IEC 413 07 Figure 3 Measurement set up to limit angle of acceptance by imaging the apparent source onto the plane of the field stop 55 1604 2553 60825 1 IEC 2007 107 Circular Circular field stop Aisgis ol aperture stop acceptance Active area of the detector IL Source Measuring distance r IEC 414 07 NOTE When the apparent source is not accessible this set up is not appropriate Figure 4 Measurement set up to limit angle of acceptance by placing a circular aperture or a mask serving as field stop close to the apparent source For condition 2 for determination of the accessible emission as well as of the angular subtense of the apparent source a positive lens L1 with a focal length of 35 mm and an aperture with a diameter of 7 mm is to be placed see Figure 5 at a distance of 35 mm from the reference point as given in Table
77. can only emit one pulse in a time base of 100 s then the duration of the pulse can be used for the exposure duration Choosing a Class 3B laser product Table 9 gives the AELs as 21060 nm AEL1060 0 15 J 150 mJ 580 nm 1 530 0 03 J 30 mJ The effect of these two wavelengths is additive see 8 3 b and Table 2 for classification of laser products with radiation of multiple wavelengths Hence need to determine if 10600 530 AEL 1060 AEL 530 Substituting the appropriate values in mJ gives 100 25 150 30 1 5 Since this is greater than 1 the laser product must be of higher classification Therefore laser product is Class 4 Example B 3 4 Classify a carbon dioxide laser A 10 6 um used for an open beam security system Assume an average output power of 0 4 W a beam diameter of 2 mm and a beam divergence of 1 mrad Solution Choose Class 3R and a 100 s time base intentional viewing is not expected 1604 2553 60825 1 IEC 2007 145 Table 7 gives the AEL for Class 3R as 5 000 W m Note Table 11 gives the limiting aperture for a 100 s exposure as 3 5 mm but the laser beam diameter is only 2 mm In order to calculate the beam irradiance E P area we should use which ever is the greater of the actual beam diameter or the limiting aperture thus E 5x04 446 x104 Wm ME Cr 10 3 This exceeds the AEL for Class 3R Table 9 gives the AEL for Class 3B a
78. cceptance a Photochemical retinal limits For measurements of sources to be evaluated against the photochemical limits 400 nm to 600 nm the limiting angle of acceptance ypp is for 10s lt ts 100 s Yph 11 mrad for 100 s lt t lt 104 s Yph 1 1 10 5 mrad for 104s lt t lt 3 x 104 s Yph 110 mrad If the angular subtense of the source is larger than the specified limiting angle of acceptance yph the angle of acceptance should not be larger than the values specified for Yph If the angular subtense of the source a is smaller than the specified limiting angle of acceptance yp the angle of acceptance should fully encompass the source under consideration but need not otherwise be well defined i e the angle of acceptance needs not be restricted to yop NOTE For measurements of single sources where a Yon it will not be necessary to measure with a specific well defined angle of acceptance To obtain a well defined angle of acceptance the angle of acceptance can be defined by either imaging the source onto a field stop or by masking off the source see Figures 3 and 4 respectively b All other limits For measurement of radiation to be compared with limits other than the retinal photo chemical hazard limit the angle of acceptance should fully encompass the source under consideration i e the angle of acceptance should be at least as large as the angular subtense of the source a However if a gt
79. ce sss 107 Figure 5 Experimental set up for the determination of the accessible emission above and the angular subtense of the apparent source below for condition 2 when an extended source is to be considered i e not using the default simplified 109 Figure B 1 Flowchart guide for the classification of laser products from supplied 1 11 2 Ee 131 Figure B 2 Flowchart guide for the classification of Class 1M and Class 2M laser er 8 135 Figure B 3 AEL for Class 1 ultra violet laser products for selected emission durations from 1079 sto TOS 333 3 0 137 Figure B 4 AEL for Class 1 ultra violet laser products for emission durations from 10 9 s to 103 s at selected Wavelengths ccccccccccccccccccessesseseeeeeeccescesteseeseeeeeeeeeses 137 Figure B 5 AEL for Class 1 visible and selected infra red laser products case Cg 1 139 Figure D 1 Anatomy of the eye cece cece cece eee eect e eee eens eene nhe neni ne neni esa nets nn renean 159 Figure D 2 Diagram of laser induced damage in biological systems 163 Figure E 1 Radiance as a function of wavelength ssss mH 179 1604 2553 60825 1 IEC 2007 7 Table 1
80. ced or relaxed requirements reduced requirements both for the manufacturer e g no key switch beam stop or attenuator and interlock connector required and the user The B for Class 3B has historical origins as in the pre Amendment A2 2001 version of the standard a Class 3A existed which had a similar meaning to what is now Class 1M and Class 2M It should be noted that for the above descriptions whenever hazardous is used or there is a reference to a high risk of injury this hazard and risk only exists within the area around the laser where the corresponding MPE levels are exceeded For exposure of the naked eye this area is bounded by the NOHD or for well collimated Class 1M and 2M viewed with binoculars or telescopes the extended NOHD ENOHD It may well be that a particular Class 3B or Class 4 laser product has a very short NOHD associated with it so that for a particular installation or application for personnel outside the NOHD eye protection is not necessary Examples of such installations are scanning lasers or line lasers mounted on the ceiling of the manufacturing hall that project a pattern or line onto the workpiece in the work area below While the power level and scan pattern could be such that the exposure in the work area is below the MPE and therefore safe maintenance and service routines will need special consideration For example exposure at closer distances might be hazardous for instance when the user is
81. ct or panels is acceptable 28 1604 2553 60825 1 IEC 2007 53 Symbol and border black Background yellow Dy D D 92 IEC 411 07 Dimensions in millimetres The dimensions D4 Dz D3 g4 and d are recommended values NOTE 1 The relationship between the greatest distance L from which the label can be understood and the minimum area A of the label is given by A L 2 000 where A and L are expressed in square metres and metres respectively This formula applies for distance less than about 50 m NOTE 2 These dimensions are recommended values As long as they are proportional to the values the symbol and border may be of any legible size as required to suit the size of the laser product Figure 1 Warning label Hazard symbol 29 1604 2553 60825 1 IEC 2007 55 Legend and border black Background yellow Space for legend d e Y 93 c 92 1 ce b a IEC 412 07 Dimensions in millimetres Minimum height of lettering 26 x 52 52 x 105 84 x 148 100 x 250 140 x 200 140 x 250 140 x 400 200 x 250 200 x 400 250 x 400 Lettering shall be of a size which renders it legible 00001010 P Inm Inm The dimension g is recommended NOTE 1 The relationship between the greatest distance L from which the label can be understood and the
82. ctor which permits the connection of external controls placed apart from other components of the laser product see 4 4 3 75 safety interlock automatic device associated with each portion of the protective housing of a laser product to prevent human access to Class 3R Class 3B or Class 4 laser radiation when that portion of the housing is removed opened or displaced see 4 3 3 76 scanning laser radiation laser radiation having a time varying direction origin or pattern of propagation with respect to a stationary frame of reference 3 77 service performance of those procedures or adjustments described in the manufacturer s service instructions which may affect any aspect of the product s performance It does not include maintenance or operation 3 78 service panel access panel that is designed to be removed or displaced for service 3 79 single fault condition any single fault that might occur in a product and the direct consequences of that fault 3 80 small source source with an angular subtense a less than or equal to the minimum angular subtense amin 22 1604 2553 60825 1 IEC 2007 41 3 81 specular reflection reflection from a surface that can be considered a beam see 3 11 including reflections from mirrored surfaces NOTE This definition is intended to recognise that some reflecting surfaces such as parabolic reflectors may increase the hazard from an incident beam or at least
83. d on the lens characteristics of the eye thermal diffusion of energy from larger retinal images is less efficient leading to a retinal spot size dependence for thermal injury which does not exist for photochemical injury dominating only in the 400 nm to 600 nm spectral region In addition eye movements further spread the absorbed energy for CW laser exposures leading to different dependencies of risk for differing retinal image sizes In the derivation of limits for ocular exposure in the retinal hazard region correction factors for eye movements were only applied for viewing durations exceeding 10 s Although physiological eye movements known as saccades do spread the absorbed energy in minimal retinal images of the order of 25 um or less within the 0 1 s to 10 s time regime the limits provide a desired added safety factor for this viewing condition At 0 25 s the mean retinal spot illuminated is approximately 50 um By 10s the illuminated retinal zone becomes approximately 75 um and the added safety factor for the minimal image condition becomes 1 7 over a stabilized eye with the spot size dependence taken into account By 100 s it is rare to achieve an illuminated zone measured at 50 points as small as 135 um leading to an additional safety factor of 2 3 or more for the minimal image condition 8T 1604 2553 60825 1 IEC 2007 171 The data from eye movement studies and retinal thermal injury studies were combi
84. default evaluation is usually the appropriate one i e produces equivalent results to the extended source method as described in 9 3 3 9 3 2 Default simplified evaluation The default simplified measurement distances in Table 11 are applicable for sources with wavelengths less than 400 nm and larger than 1 400 nm or ifthe factor Cg is set equal to 1 or for the photochemical retinal limit for time base values longer than 100 s when the measurement angle of acceptance is not restricted i e shall be at least as large as the angular subtense of the apparent source for other limits that are neither photochemical nor thermal i e do not depend on Cg retinal limits such as the AEL of Class 3B The distances specified in Table 11 are defined as distance from the reference points listed in Table 12 53 1604 2553 60825 1 IEC 2007 103 Table 11 Measurement aperture diameters and measurement distances for the default simplified evaluation Condition 1 Condition 2 Condition 3 applied to collimated applied to diverging beam applied to determine irradiation beam where e g where e g magnifying relevant for the unaided eye telescope or binoculars glasses microscopes may and for scanning beams may increase the increase the hazard hazard Aperture Distance Aperture Distance Aperture stop Wavelength stop mm ONE ue nm mm mm i TT DE 23025 040 25 200 7 70 1i w 1 Di
85. dered for the determination of the accessible emission for comparison with photochemical retinal limits 1604 2553 60825 1 IEC 2007 105 The accessible emission and the AEL Cg are determined together i e they are paired values at different positions within the beam and the values obtained for the most restrictive position are used to determine the class of the product This implies that the accessible emission that is compared to the AEL and the AEL are determined for the same position within the beam i e the angular subtense of the apparent source and therefore Cg is determined at the position of the aperture stop that is used to determine the accessible emission NOTE 1 In the case where the divergence of the laser beam is less than 1 5 mrad then the angular subtense of the apparent source a is amin and the determination of the accessible emission may be performed under the conditions specified in 9 3 1 NOTE 2 f the source is diffuse for instance a laser beam incident on a transmissive diffuser plate then the diffuser can be considered as the location of the apparent source and the emission pattern at the diffuser can be used to determine the angular subtense of the apparent source see 8 3 d for the evaluation method of non uniform patterns NOTE 3 In some more complex arrangements with multiple sources or multiple focal points it may be more appropriate to use a more elaborate technique such as r
86. ds may contain additional requirements Consideration should also be given to the intended application and user group For example a class 3B or class 4 laser product may not be suitable for use as a consumer product 1604 2553 60825 1 IEC 2007 15 Where a laser system forms a part of equipment which is subject to another IEC product safety standard e g for medical equipment IEC 60601 2 22 IT equipment IEC 60950 audio and video equipment IEC 60065 equipment for use in hazardous atmospheres IEC 60079 or electric toys IEC 62115 this Part 1 will apply in accordance with the provisions of IEC Guide 1042 for hazards resulting from laser radiation If no product safety standard is applicable then IEC 61010 1 applies In previous editions LEDs were included in the scope of IEC 60825 1 and they may be still included in other parts of the IEC 60825 series However with the development of lamp safety standards optical radiation safety of LEDs in general can be more appropriately addressed by lamp safety standards The removal of LEDs from the scope of this Part 1 does not preclude other standards from including LEDs whenever they refer to lasers CIE S009 may be applied to determine the risk group class of an LED or product incorporating one or more LEDs The MPE maximum permissible exposure values of this Part 1 were developed for laser radiation and do not apply to collateral radiation However if a concern exi
87. e MPEs at 10 13 s In the wavelength range between 450 nm and 500 nm dual limits apply and the exposure must not exceed either limit applicable d For repetitively pulsed UV lasers neither limit should be exceeded 4002 O3l L 82809 SLL 6 7 091 UCN in the wavelength range from 400 nm to 1 400 nm retinal hazard region Table A 2 Maximum permissible exposure MPE at the cornea for exposure to laser radiation from extended sources Exposure time t Wave S length 10 13 10711 10 9 1 8 x 10 5 5 x 10 5 10 102 104 nm to to to to to to to to 10711 10 9 1 8 x 10 5 5 x 10 5 10 102 104 3 x 104 400 nm to 600 nm Retinal photochemical hazard 100 C4 J m 2 1 C4 W m 2 1 C4 W m using using using Yoh 11 mrad Yon 1 1 1 5 mrad Yn 110 mrad 400 to 700 1 5 x 10 4 CgJ m 2 2 7 x 104 9 75 Cg J m 5x 10 3 C J m 18 1075 Cg J m 2 AND 400 nm to 700 nm Retinal thermal hazard 18 Cg 72 0 25 W m 2 t lt To t gt T2 18 10 75 C J m 4 4 70 75 zi m 700 to 1 050 s EA ME pn C4 Cs 5x 10 3 Cy CeJ m 2 18 075 C Cg J m 2 18 Cy Cs C T 025 W m T Hm t lt Tp t gt To tosota agoj CeCe eI 5 x 10 2 C s C J m 2 90 10 75 C4 C Jm 2 18 975 C4 Ce C Jm a The angle yp is the limiting measurement angle of acceptance b n the wavelength range between 400 nm and 600 nm dual limits apply and the exposure must
88. e as components of any system for subsequent sale are not subject to IEC 60825 1 since the final product will itself be subject to this standard However if the laser system within the laser product is operable when removed from the equipment the requirements of this Part 1 apply to the removable unit NOTE 1 Operable equipment does not require a tool to prepare for operation Any laser product is exempt from all further requirements of this Part 1 if classification by the manufacturer of that product according to Clauses 3 8 and 9 shows that the emission level does not exceed the AEL accessible emission limit of Class 1 under all conditions of operation maintenance service and failure NOTE 2 The above exemption is to ensure that inherently safe laser products are not unnecessarily subject to the standard In addition to the hazards resulting from laser radiation laser equipment may also give rise to other hazards such as fire and electric shock NOTE 3 However the classification and other requirements of this standard are intended to address only the laser radiation hazards to the eyes and skin Other hazards are not included within its scope This Part 1 describes the minimum requirements Compliance with this Part 1 may not be sufficient to achieve the required level of product safety Laser products must conform to the applicable performance and testing requirements of the applicable product safety standards NOTE 4 Other standar
89. e beam image size is also of great importance as the degree of 84 1604 2553 60825 1 IEC 2007 165 peripheral spread due to conduction is a function of the size as well as the temperature of the initial area of tissue heating This type of thermal lesion is commonly seen on exposure to CW or long pulsed lasers but also occurs with short pulses For irradiated spot sizes of the order of 1 mm to 2 mm or less the radial heat flow leads to a spot size dependence of injury Photochemical effects On the other hand damaging effects can be the direct result of a photochemical process This process is created by absorption of given light energy Rather than releasing the energy the species undergo a chemical reaction unique to their excited state This photochemical reaction is believed to be responsible for damage at low levels of exposure By this mechanism some biological tissues such as the skin the lens of the eye and in particular the retina may show irreversible changes induced by prolonged exposure to moderate levels of UV radiation and short wavelength light Such photochemically induced changes may result in damage to a system if the duration of irradiation is excessive or if shorter exposures are repeated over prolonged periods Some of the photochemical reactions initiated by laser exposure may be abnormal or exaggerations of normal processes Photochemical reactions generally follow the Law of Bunsen and Roscoe f
90. e contribution of collateral radiation to the measurement Class 1 and 1M Class 1 is applicable to the wavelength range of 180 nm to 1 mm Class 1M is applicable to the wavelength range of 302 5 nm to 4 000 nm For determination of the accessible emission under condition 1 condition 2 and condition 3 see Table 11 For wavelengths less than 302 5 nm and greater than 4 000 nm if the accessible emission is less than the AEL of Class 1 for condition 3 then the laser product is assigned to Class 1 For wavelengths between 302 5 nm and 4 000 nm If the radiation level is less than the AEL of Class 1 for condition 1 and condition 2 and condition 3 then the laser product is assigned to Class 1 If the accessible emission is greater than the AEL of Class 1 for condition 1 or condition 2 and less than the AEL of Class 3B for condition 1 and condition 2 and less than the AEL of Class 1 for condition 3 then the laser product is assigned to Class 1M NOTE 1 Typically the accessible emission of a Class 1M product exceeds the Class 1 AEL for either condition 1 or condition 2 However it may also be classified as Class 1M when it exceeds that AEL for both condition 1 and condition 2 NOTE 2 The reason for verifying the AEL of Class 3B is to limit the maximum power passing through an optical instrument If the accessible emission exceeds the value given in Table 9 for the AEL of Class 3B as determined with a 3 5 mm diamet
91. e in many ways rather restrictive and worst case there are still limitations which in rare cases may lead to hazards beyond the hazards that are associated with the respective classes Classification is based on three components a the AEL of the different classes b the measurement requirements in terms of measurement distance aperture diameter and angle of acceptance to reflect potential exposure conditions These measurement requirements for a given laser product determine the accessible emission that is compared to the AEL to determine the class C the test conditions under which the AEL and the accessible emission is determined This would include taking account of reasonably foreseeable single fault conditions Also operational maintenance and service need to be distinguished The use of accessories and different configurations of the product that can be achieved without using tools needs to be considered Each of these three components has some implicit assumptions so that in rare cases where these assumptions are not met hazards beyond the usual understanding of the class can arise For instance the AEL for Class 1 and 1M for long term exposure is based on the assumption of eye movements of a non anaesthetised eye However if prolonged ocular exposure occurs during medical procedures for an anaesthetised eye then Class 1 laser emission may lead to potentially hazardous exposures Also the measurement requirements are b
92. e of the Class 2M label could read DO NOT EXPOSE USERS OF BINOCULARS OR TELESCOPES If the accessible emission exceeds the AEL of Class 3B as determined with a 3 5mm diameter aperture placed at the closest point of human access an additional warning is to be given on a product label and in the information for the user SKIN EXPOSURE NEAR APERTURE MAY CAUSE BURNS 31 1604 2553 60825 1 IEC 2007 59 NOTE Only applies if condition 2 is used to determine the AEL 5 4 Class 3R Each Class 3R laser product shall have affixed a warning label Figure 1 and an explanatory label Figure 2 bearing the words LASER RADIATION AVOID DIRECT EYE EXPOSURE CLASS 3R LASER PRODUCT NOTE Labels using AVOID EXPOSURE TO BEAM in the second line would also be acceptable 5 5 Class 3B Each Class 3B laser product shall have affixed a warning label Figure 1 and an explanatory label Figure 2 bearing the words LASER RADIATION AVOID EXPOSURE TO BEAM CLASS 3B LASER PRODUCT 5 6 Class 4 Each Class 4 laser product shall have affixed a warning label Figure 1 and an explanatory label Figure 2 bearing the words LASER RADIATION AVOID EYE OR SKIN EXPOSURE TO DIRECT OR SCATTERED RADIATION CLASS 4 LASER PRODUCT 5 7 Aperture label Each Class 3R Class 3B and Class 4 laser product shall have affixed a label close to each aperture through which laser radiation in excess of the AEL for Class 1 or Class 2 is emitted T
93. eatest At times greater than 10 s heat conduction redistributes the thermal energy so that the impact of the penetration depth is no longer significant D 2 3 Skin hazards In general terms the skin can tolerate a great deal more exposure to laser beam energy than can the eye The biological effect of irradiation of skin by lasers operating in the visible 400 nm to 700 nm and infra red greater than 700 nm spectral regions may vary from a mild erythema to severe blisters An ashen charring is prevalent in tissues of high surface absorption following exposure to very short pulsed high peak power lasers This may not be followed by erythema The pigmentation ulceration and scarring of the skin and damage of underlying organs may occur from extremely high irradiance Latent or cumulative effects of laser radiation have not been found prevalent However some limited research has suggested that under special conditions small regions of human tissue may be sensitized by repeating local exposures with the result that the exposure level for minimal reaction is changed and the reactions in the tissues are more severe for such low level exposure In the wavelength range 1 500 nm to 2 600 nm biological threshold studies indicate that the risk of skin injury follows a similar pattern to that of the eye For exposures up to 10 s the MPE is increased within this spectral range 89 1604 2553 60825 1 IEC 2007 175 D 3
94. ent source it is obvious that condition 2 will be more restrictive than condition 1 Choose Class 1 and a 100 s time base see 8 36 thus for a laser with a x 1 5 mrad and t gt T where T 10 s for a lt 1 5 mrad see Table 10 the AEL is obtained from Table 4 as follows AEL 3 9 x 10 4C C gt W Where from Table 10 C 100 0020 700 2 51 and C 1 Therefore AEL 0 98 mW Since this is less than the laser diode is emitting into a 7 mm aperture 70 mm from the laser it would imply that the product exceeds Class 1 classification for condition 2 However when we compare the condition 3 data with the AEL for Class 1 laser products the product meets the requirements for Class 1 Since the product satisfies the requirements for Class 1 classification for Conditions 1 and 3 but fails condition 2 for Class 1 without exceeding the AEL for Class 3B it is classified Class 1M If the user fits a collimating lens to this laser diode the product may need reclassifying 73 1604 2553 60825 1 IEC 2007 143 Example B 3 3 Classify a single pulsed frequency doubled neodymium laser with the following output characteristics assume both wavelengths are emitted at the same time Output pulse energy is 100 mJ at 1 060 nm Output pulse energy is 25 mJ at A 530 nm Pulse duration 25 ns Exit aperture diameter 5 mm Beam divergence at each wavelength lt 1 mrad Solution Assuming the laser
95. ependent upon the angular subtense of the source If the angular subtense of the source is larger than the specified limiting angle of acceptance y the angle of acceptance y is limited to y and the source is scanned for hotspots If the measurement angle of acceptance y is not limited to the specified level the hazard may be over estimated NOTE If the angular subtense of the apparent source is smaller than the specified limiting angle of acceptance the actual measurement angle of acceptance does not affect the measurement and does not have to be limited i e a regular open angle of acceptance radiometer set up can be used Symbol 7 3 51 limiting angle of acceptance for evaluating thermal hazards the maximum angular subtense to be used for the evaluation of the retinal thermal hazard The value of the angle of acceptance y may vary between and a see 8 3 d 9 3 2 b 2 Symbol vin 3 52 limiting aperture circular area over which irradiance and radiant exposure are averaged 18 1604 2553 60825 1 IEC 2007 33 3 53 maintenance performance of those adjustments or procedures specified in user information provided by the manufacturer with the laser product which are to be performed by the user for the purpose of assuring the intended performance of the product It does not include operation or service 3 54 maximum angular subtense Omax value of angular subtense of the appa
96. er class and repeat calculations Yes Do you need to check if product could satisfy AEL of a lower class No Figure B 1 Flowchart guide for the classification of laser products from supplied output parameters 68 1604 2553 60825 1 IEC 2007 133 NOTE 1 AEL ingle is determined on the duration of a single pulse AEL p r is calculated from AEL determined on the chosen time base where If AELr is in J or J m then AEL Sq AEL N in units of J or J m If AEL is in W or Wm then AEL spT AEL PRF in units of J or J m T chosen time base in seconds Nr number of pulses in time T NOTE2 If multiple pulses occur within the period Ti change single pulse duration to T and calculate new value of AEL ingle Change PRF accordingly to determine maximum allowed value of N 8 3 f Divide the new value of AEL ingie by the number of original pulses contained in the period T before substituting final value of AEL in equation for AEL single S p train 69 1604 2553 60825 1 IEC 2007 Choose one of the following Classes 1 2 3R 3B Choose higher class and repeat calculations if chosen class was 3B then laser is Class 4 Choose lower class and repeat calculations Finish laser is Class 1M or Class 2M Is laser output measured with Condition 3 of Table 11 less than AEL of Class 1 or Class 2 135 Select applicable time base 8 3e Is
97. er aperture placed at the closest point of human access an additional warning regarding a potential skin hazard is to be given see 5 2 NOTE 3 It is possible that a Class 1M laser product with a highly diverging beam can produce high enough irradiance levels near to or in contact with the source for instance a fibre tip so that skin injury is possible Class 2 and 2M Classes 2 and 2M are applicable to the wavelength range of 400 nm to 700 nm For determination of the accessible emission under condition 1 condition 2 and condition 3 see Table 11 If the accessible emission exceeds the limits as required for Class 1 and for Class 1M see item g and is less than the AEL of Class 2 for condition 1 and condition 2 and condition 3 then the laser product is assigned to Class 2 44 1604 2553 60825 1 IEC 2007 85 If the accessible emission exceeds the limits as required for Class 1 and for Class 1M see item g and is greater than the AEL of Class 2 for condition 1 or condition 2 and less than the AEL of Class 3B for condition 1 and condition 2 and less than the AEL of Class 2 for condition 3 then the laser product is assigned to Class 2M NOTE 1 The reason for verifying the AEL of Class 3B is to limit the maximum power passing through an optical instrument and to preclude high irradiance levels near to or in contact with diverging sources which may lead to skin injury NOTE 2 Typica
98. f direction of the beam must be considered The analysis shall include whether the single fault event will result in sufficient energy to degrade or destroy the protective housing For example when during operation or single fault condition the introduction of robotics or other beam manipulation mechanisms or the use of optics or workpieces would result in energy being directed onto the surface of the protective housing one of the following shall occur the single fault shall be eliminated by engineering means or the housing material shall withstand the energy without degradation of its protective properties sufficient to allow a hazardous exposure to laser energy or the fault shall be detected and emission of laser radiation through the protective housing shall be prevented before degradation can occur Evaluation times of the protective housing of less than 30 000 s as specified in IEC 60825 4 are not applied for the classification of the product NOTE 1 This is because the classification must be considered without human intervention see 4 2 1 and therefore inspection of the protective housing by the user is not considered NOTE 2 Protective housing evaluations that consider human inspection or intervention may be used to establish levels of safety or for the detection of potential degradation of the housing which results from reasonably unforeseeable fault events or multiple fault events independent of the product classific
99. g i e Cg 7 x a amin The expression 7 x a shall be limited to Omax prior to the calculation of Cg The 7x value of a shall be used for the determination of T of Table 10 NOTE For cases where a 1 5 mrad but 7 x a gt 1 5 mrad the limits for gt 1 5 mrad of Table 5 and 8 apply Non uniform retinal image irradiance profile non circular and multiple sources For comparison with the thermal retinal limits if the wavelength range is from 400 nm to 1 400 nm and the AEL depends on Cg then if the retinal image does not have a uniform irradiance profile or the retinal image profile consists of multiple points For a Gaussian retinal irradiance profile as produced by a TEMog beam the angular subtense can be determined with the dg4 diameter criterion and an analysis of partial areas is not necessary 39 1604 2553 60825 1 IEC 2007 75 then measurements or evaluations shall be made for each of the following scenarios for every single point and for various assemblies of points and for partial areas This is necessary in order to ensure that the AEL is not exceeded for each possible angle a subtended in each scenario For the evaluation of assemblies of points or for partial areas the angle of acceptance y is to be varied between amin and i e ai lt Y lt to determine the partial accessible emission associated with the respective scenario For the compar
100. g an interlock including configurations and settings against which the operation and maintenance instructions contain warnings For example when optical elements such as filters diffusers or lenses in the optical path of the laser beam can be removed without tools the product must be tested in the configuration which results in the highest hazard level The instruction by the manufacturer not to remove the optical elements cannot justify classification as a lower class Classification is based on the engineering design of the product and cannot be based on appropriate behaviour of the user 43 1604 2553 60825 1 IEC 2007 83 c For a laser product other than a laser system with the laser coupled to that type of laser energy source which is specified as compatible by the laser product manufacturer and which produces the maximum emission of accessible radiation from the product At points in space to which human access is possible during operation for measurement of accessible emission levels for example if operation may require removal of portions of the protective housing and defeat of safety interlocks measurements shall be made at points accessible in that product configuration With the measuring instrument detector so positioned and so oriented with respect to the laser product as to result in the maximum detection of radiation by the instrument Appropriate provision shall be made to avoid or to eliminate th
101. he beam Equation E 3 reduces to E 5 For MPEs expressed as radiant exposure a slightly different method was used Radiant exposure is defined as dQ H gt E 6 dA Ve where Q is radiant energy expressed in Joules Dividing by time yields 2 E 7 dt dA dt As radiant power is expressed as ag E 8 dt equation E8 can be substituted into equation E 7 yielding H do E 9 dt dA Returning to equation E 1 we substitute equation E 9 to yield E10 dO dt cos 94 1604 2553 60825 1 IEC 2007 185 Again substituting equation E 4 and assuming the worst case scenario of 0 0 we obtain E 11 For the calculations we assumed a worst case scenario of a 100 mrad angular subtense for an exposure duration of 100 s The results are listed in Table E 1 and plotted in Figure E 1 95 1604 2553 60825 1 IEC 2007 187 Annex F informative Summary tables Table F 1 summarizes the physical quantities referred to in this Part 1 and gives the unit and the symbol for the unit used for each of them The definitions of the SI base units are taken from ISO 1000 The units and symbols are taken from IEC 60027 1 Table F 2 summarizes the manufacturer s requirements Table F 1 Summary of the physical quantities used in this Part 1 Quantity Name of unit Unit symbol Definition Length m The metre is the length of the path travelled by light in vacuum duri
102. he label s shall bear the words LASER APERTURE or APERTURE FOR LASER RADIATION or AVOID EXPOSURE LASER RADIATION IS EMITTED FROM THIS APERTURE 5 8 Radiation output and standards information The name and publication date of the standard to which the product was classified shall be included on the explanatory label or elsewhere in close proximity on the product Each laser product except those of Class 1 shall be described on the explanatory label Figure 2 by a statement of the maximum output of laser radiation see definition 3 55 the pulse duration if appropriate and the emitted wavelength s For Class 1 and Class 1M instead of the labels on the product the information may be contained in the information for the user 32 1604 2553 60825 1 IEC 2007 61 5 9 Labels for access panels 5 9 1 Labels for panels Each connection each panel of a protective housing and each access panel of a protective enclosure which when removed or displaced permits human access to laser radiation in excess of the AEL for Class 1 shall have affixed labels bearing the words for the case of an embedded Class 1M laser the statement instead may be included in the information for the user a CAUTION CLASS 1M LASER RADIATION WHEN OPEN DO NOT VIEW DIRECTLY WITH OPTICAL INSTRUMENTS if the accessible radiation does not exceed the AEL for Class 1M where the level of radiation is measured according to 9 2 g and 9 3
103. he most important of which are wavelength pulse duration image size irradiance and radiant exposure In general terms in supra threshold exposures the predominating mechanism is broadly related to the pulse duration of the exposure Thus in order of increasing pulse duration the predominant effects in the following time domains are in nanosecond and sub nanosecond exposures acoustic transients and non linear effects from 1 ms to several seconds thermal effects and in excess of 10 s photochemical effects 83 1604 2553 60825 1 IEC 2007 163 Laser radiation is distinguished from most other known types of radiation by its beam collimation This together with an initial high energy content results in excessive amounts of energy being transmitted to biological tissues The primary event in any type of laser radiation damage to a biological system is the absorption of optical radiation by that system Absorption occurs at an atomic or molecular level and is a wavelength specific process Thus it is the wavelength that determines which tissue a particular laser beam is liable to damage 5 Key Y v v a Laser energy is absorbed by the system CU b The absorbed energy produces heat which is conducted to surrounding tissues Y vv c Inlong pulse or CW lasers the persistence of the thermal front gives rise to a progressively enlarging lesion Y d
104. held responsible for identifying any or all such patent rights International Standard IEC 60825 1 has been prepared by IEC technical committee 76 Optical radiation safety and laser equipment This second edition of IEC 60825 1 cancels and replaces the first edition published in 1993 its Amendment 1 1997 and its Amendment 2 2001 It constitutes a technical revision The user s guide has been removed from this part of the IEC 60825 series and is now a separate document Part 14 Light emitting diodes LEDs have been removed from the scope of this part of IEC 60825 but may still be included in other parts 1604 2553 60825 1 IEC 2007 11 This part of IEC 60825 has the status of a Group Safety Publication in accordance with IEC Guide 1041 for aspects of laser radiation pertaining to human safety The text of this standard is based on the following documents CDV Report on voting 76 338 CDV 76 357 RVC Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table This publication has been drafted in accordance with the ISO IEC Directives Part 2 The list of all parts of the IEC 60825 series published under the title Safety of laser products can be found on the IEC website This part of IEC 60825 is also referred to as Part 1 in this publication The committee has decided that the contents of this publication will remain unchanged unt
105. il the maintenance result date indicated on the IEC web site under http webstore iec ch in the data related to the specific publication At this date the publication will be reconfirmed withdrawn replaced by a revised edition or amended 1 IEC Guide 104 1 997 The preparation of safety publications and the use of basic safety publications and group safety publications It gives guidance to IEC technical committees and to writers of specifications concerning the manner in which safety publications should be drafted This guide does not constitute a normative reference and reference to it is given for information only ag 1604 2553 60825 1 IEC 2007 13 SAFETY OF LASER PRODUCTS Part 1 Equipment classification and requirements 1 Scope and object IEC 60825 1 is applicable to safety of laser products emitting laser radiation in the wavelength range 180 nm to 1 mm A laser product may consist of a single laser with or without a separate power supply or may incorporate one or more lasers in a complex optical electrical or mechanical system Typically laser products are used for demonstration of physical and optical phenomena materials processing data reading and storage transmission and display of information etc Such systems have found use in industry business entertainment research education medicine and consumer products Laser products that are sold to other manufacturers for us
106. ing from temporary disturbance of vision or from startle reactions Such visual disturbances could be of particular concern connected with performing safety critical operations such as working with machines or at height with high voltages or driving Users are instructed by labelling not to stare into the beam i e to perform active protective reactions by moving the head or closing the eyes and to avoid continued intentional intrabeam viewing Class 2M Laser products that emit visible laser beams and are safe for short time exposure only for the naked unaided eye Eye injury may occur following exposure with one of the two categories of optical viewing instruments eye loupes or binoculars under the following conditions a for diverging beams if the user places optical components within 100 mm from the source to concentrate collimate the beam or b for a collimated beam with a diameter larger than the measurement diameter specified for condition 3 see Table 11 However dazzle flash blindness and afterimages may be caused by a beam from a Class 2M laser product particularly under low ambient light conditions This may have indirect general safety implications resulting from temporary disturbance of vision or from startle reactions Such visual disturbances could be of particular concern if experienced while performing safety critical operations such as working with machines or at height with high voltages or driving m
107. ings and precautions to be taken to avoid possible exposure to laser radiation above Class 1 and other hazards a schedule of maintenance necessary to keep the product in compliance alist of those controls and procedures which could be utilized by persons other than the manufacturer or his agents to increase accessible emission levels of radiation a clear description of the location of displaceable portions of the protective housing which could allow access to laser radiation in excess of the accessible limits in Tables 4 to 9 protective procedures for service personnel and legible reproductions colour optional of required labels and hazard warnings Additional requirements for specific laser products Other parts of the standard series IEC 60825 For specific applications one or other of the following IEC 60825 series may be applicable see also Bibliography IEC 60825 2 Safety of optical fibre communication systems provides application notes and examples 1604 2553 60825 1 IEC 2007 69 IEC 60825 4 Laser guards provides design and construction information for laser guards and materials especially where high power lasers are used IEC 60825 12 Safety of free space optical communication systems used for transmission of information Further information may be found in I1EC TR 60825 3 Guidance for laser displays and shows EC TR 60825 5 Manufacturer s checklist
108. is accurate IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user In order to promote international uniformity IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with an IEC Publication All users should ensure that they have the latest edition of this publication No liability shall attach to IEC or its directors employees servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury property damage or other damage of any nature whatsoever whether direct or indirect or for costs including legal fees and expenses arising out of the publication use of or reliance upon this IEC Publication or any other IEC Publications Attention is drawn to the Normative references cited in this publication Use of the referenced publications is indispensable for the correct application of this publication Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights IEC shall not be
109. is determined by the ratio of the diameter of the field stop and the lens to field stop distance image distance Figure 3 or by the ratio of the diameter of the field stop and the source detector distance Figure 4 Losses due to the lens have to be taken into account For condition 2 and condition 3 the angle of acceptance for the determination of the accessible emission level shall be as stated in 1 and 2 below For condition 1 the angle of acceptance is determined by dividing the values given in 1 and 2 by a factor 7 1 Photochemical retinal limits For measurements of sources to be evaluated against the photochemical limits 400 nm to 600 nm the limiting angle of acceptance ypp is given in Table 13 Table 13 Limiting angle of acceptance yp Emission duration Yph for condition 1 7 for condition 2 and S mrad condition 3 mrad 10 t x 100 1 57 11 100 t 104 0 16 x 10 9 1 1 t05 104 t lt 3 x 104 16 110 57 1604 2553 60825 1 IEC 2007 111 If the angular subtense of the source a is larger than the specified limiting angle of acceptance yp the angle of acceptance should not be larger than the values specified for Yph If the angular subtense of the source a is smaller than the specified limiting angle of acceptance jpn the angle of acceptance shall fully encompass the source under consideration but need not otherwise be well defined i e the angle of acce
110. is shall include a statement in appropriate units of wavelength beam divergence pulse duration and repetition rate or description of irregular pulse pattern maximum power or energy output The values shall where appropriate include cumulative measurement uncertainties and any expected increase in the measured quantities at any time after manufacture Duration of pulses resulting from unintentional mode locking need not be specified whereas those conditions associated with the product known to result in unintentional mode locking shall be specified For ultrashort pulses the bandwidth of the radiation i e the wavelength range of emission shall be specified For embedded laser products and other incorporated laser products information to describe the incorporated laser see item c The information shall also include appropriate safety instructions to the user to avoid inadvertent exposure to hazardous laser radiation This is particularly relevant for embedded laser products that are classified as Class 1 Class 1M Class 2 or Class 2M but where intrabeam viewing to accessible emission levels in excess of the AELs of these classes is possible during maintenance In this case the manufacturer shall include a warning that intrabeam viewing of the laser shall be prevented Where appropriate and relevant the applicable MPE and NOHD for Class 3B and Class 4 laser products Since the NOHD greatly depends on the beam delivery sy
111. ison of these partial accessible emission levels with the respective AEL the value of a is set equal to y Classification is to be based on the case where the ratio between the partial accessible emission within a partial area over the angular subtense of that area and the corresponding AEL is a maximum The angular subtense of a rectangular or linear source is determined by the arithmetic mean value of the two angular dimensions of the source Any angular dimension that is greater than omax or less than amin shall be limited to amax or Omin respectively prior to calculating the mean The photochemical limits 400 nm to 600 nm do not depend on the angular subtense of the source and the source is analysed with the limiting angle of acceptance specified in 9 3 3 b For sources that are larger than the limiting angle of acceptance the accessible emission has to be determined for the partial apparent source which produces the maximum emission value Time bases The following time bases are used in this standard for classification 1 0 25 s for Class 2 Class 2M and Class 3R laser radiation in the wavelength range from 400 nm to 700 nm 2 100 s for laser radiation of all wavelengths greater than 400 nm except for the cases listed in 1 and 3 3 30 000 s for laser radiation of all wavelengths less than or equal to 400 nm and for laser radiation of wavelengths greater than 400 nm where intentional long term viewing is inherent
112. ition 2 see Clause 9 highly diverging beam Alternatively the second line of the Class 1M label could read DO NOT EXPOSE USERS OF BINOCULARS OR TELESCOPES If the accessible emission exceeds the AEL of Class 3B as determined with a 3 5mm diameter aperture placed at the closest point of human access an additional warning is to be given on a product label and in the information for the user SKIN EXPOSURE NEAR APERTURE MAY CAUSE BURNS NOTE Only applies if condition 2 is used to determine the AEL 5 3 Class 2 and Class 2M Each Class 2 laser product shall have affixed a warning label Figure 1 and an explanatory label Figure 2 bearing the words LASER RADIATION DO NOT STARE INTO BEAM CLASS 2 LASER PRODUCT Each Class 2M laser product shall have affixed a warning label Figure 1 and an explanatory label Figure 2 bearing the words LASER RADIATION DO NOT STARE INTO THE BEAM OR VIEW DIRECTLY WITH OPTICAL INSTRUMENTS CLASS 2M LASER PRODUCT The type of optical instrument which could result in an increased hazard may be added in parenthesis after the word instruments The added wording could in particular be BINO CULARS OR TELESCOPES for a laser product with a collimated large diameter beam which is classified 2M because it fails condition 1 see Clause 9 or MAGNIFIERS for a laser product which is classified 2M because it fails condition 2 see Clause 9 highly diverging beam Alternatively the second lin
113. l disturbances could be of particular concern if experienced while performing safety critical operations such as working with machines or at height with high voltages or driving Class 3R lasers should only be used where direct intrabeam viewing is unlikely Class 3B Laser products that are normally hazardous when intrabeam ocular exposure occurs i e within the NOHD including accidental short time exposure Viewing diffuse reflections is normally safe Class 3B lasers which approach the AEL for Class 3B may produce minor skin injuries or even pose a risk of igniting flammable materials However this is only likely if the beam has a small diameter or is focussed NOTE There exist some theoretical but rare viewing conditions where viewing a diffuse reflection could exceed the MPE For example for Class 3B lasers having powers approaching the AEL lengthy viewing of greater than 10 s of true diffuse reflections of visible radiation and viewing at distances less than 13 cm between the diffusing surface and the cornea can exceed the MPE Class 4 Laser products for which intrabeam viewing and skin exposure is hazardous and for which the viewing of diffuse reflections may be hazardous These lasers also often represent a fire hazard 78 1604 2553 60825 1 IEC 2007 153 Note on nomenclature M in Class 1M and Class 2M is derived from magnifying optical viewing instruments R in Class 3R is derived from redu
114. l limits The class see Tables 4 to 9 is determined by applying the most restrictive of 1 2 and where applicable 3 1 The exposure from any single pulse within a pulse train shall not exceed the AEL for a single pulse 2 The average power for a pulse train of emission duration T AEL shall not exceed the power corresponding to the AEL for a single pulse of duration T NOTE For comparison with AELsingle or AEL s p train AELy should be divided by N and is termed AEL s p T 3 a For constant pulse energy and pulse duration The energy per pulse shall not exceed the AEL for a single pulse multiplied by the correction factor Cs AEL p train AELsingte x C5 where AEL p train is the AEL for a single pulse in the pulse train AEL single is the AEL for a single pulse Tables 4 to 9 N is the effective number of pulses in the pulse train within the assessed emission duration when pulses occur within 7 see Table 3 N is less than the actual number of pulses see below The maximum emission duration that needs to be considered for the assessment for wavelengths between 400 nm and 1 400 nm is 72 see Table 10 or the applicable time basis whichever is shorter For wavelengths greater than 1 400 nm the maximum duration to be considered is 10 s Cs N 0 25 Cs is only applicable to individual pulse duration shorter than 0 25 s If multiple pulses appear within the period of 7 see Table 3 they are counted as a single pu
115. laser Time duration of a single laser pulse Total exposure duration of a train of pulses Time breakpoints see Table 10 Classification of a laser product Introduction The examples presented in this annex illustrate the calculation procedures for classifying a laser product from measured parameters obtained by following the measurement conditions specified in this standard Flowcharts are provided in this Annex to illustrate the basic steps that may be needed to complete a classification calculation for a laser product but not all possible laser products have been covered by these flowcharts 1604 2553 60825 1 IEC 2007 129 As specified in 8 2 and 8 3 It is the responsibility of the manufacturer or his agent to provide correct classification of a laser product The product is classified on the basis of that combination of output power s and wavelength s of the accessible laser radiation over the full range of capability during operation at any time after manufacture which results in its allocation to the highest appropriate class The accessible emission limit AELs for Class 1 and 1M Class 2 and 2M Class 3R and Class 3B listed in order of increasing hazard are given in Tables 4 to 9 The values of the correction factors used are given in Table 10 as functions of wavelength emission duration number of pulses and angular subtense If the user modifies the laser product so that the accessible laser radiati
116. laser products and systems have received training to an appropriate level that allows them to understand the full implications of the classification scheme Modification If the modification of a previously classified laser product affects any aspects of the product s performance or intended functions within the scope of this standard the person or organization performing any such modification is responsible for ensuring the reclassification and relabelling of the laser product 4 2 Protective housing 4 2 1 General Each laser product shall have a protective housing which when in place prevents human access to laser radiation including errant laser radiation in excess of the AEL for Class 1 except when human access is necessary for the performance of the function s of the product When the classification of a laser product is based on the prevention of human access to a level of energy that is equivalent to Class 4 for instance for laser processing machines the protective housing must withstand exposures under reasonably foreseeable single fault conditions see 9 1 without human intervention If the protective housing is of a size that permits human entry see 4 12 Maintenance of Class 1 1M 2 2M or 3R laser products shall not permit human access to levels of laser radiation of Class 3B or Class 4 Maintenance of Class 3B laser products shall not permit human access to levels of laser radiation of Class 4 4 2 2 Service
117. lasers neither limit should be exceeded 4002 03l L S2809 6 7 091 UCN Eg Table 8 Accessible emission limits for Class 3R laser products in the wavelength range from 400 nm to 1 400 nm retinal hazard region extended sources 2 gt Emission duration t Wave length S A 10713 10711 1079 1077 1 8 x 1075 5 x 1075 1 x 1073 0 35 10 103 nm to to to to to to to to to to 10711 10 9 1077 1 8 x 10 5 5 x 1075 1 x 1073 0 35 10 103 3 x 10 5 0 x 1079 Cg W 8 0 75 6 t2 0 25 s 5 0 x 1079 Cg W 40010700 29x 10 ci eS Ges 8 Ce J 6 t lt 0 25 s 3 5 x 1073 10 75 Cg J 3 5 x 10 3 C4 Cg C7 12 0 25 W 2 9x10 8 5 010 75 6 t To 700 to 1 050 C4 Ce J C4 Cg J 1x 1079 C4 Cg J 3 5 x 10 3 10 75 C4 Cg ts To 35x 10 3 0 75 C4 Cg C7 J 1 050 to 29x10 7 5210 75 1 10 5 Cg C7 J 1 8 x 10 2 0 75 Cg C7 5 0 x 10 2 W 1 400 Cg C7 J Cg C7 J 6 v7 j 6 v7 a For correction factors and units see Table 10 b The AELs for emission durations less than 10 13 s are set to be equal to the equivalent power or irradiance values of the AEL at 10 13 s 400c O3al 1 862809 SSC r091 UCN 1604 2553 60825 1 IEC 2007 97 Table 9 Accessible emission limits for Class 3B laser products Emission duration t S Wave length 2 nm 10 9 0 25 to 3 x 104 400 to 700 3x107W 0 03 J for t lt 0 06 s 0 5 W 0 5 W for t2 0 06 s 700 to
118. limits the amount of radiation that is collected from large diameter or highly diverging beams For example when measured under the applicable conditions Class 1M and Class 2M products may have higher measured total energy or power than Class 2 or Class 3R For such laser products a classification of 1M or 2M is appropriate The accessible emission limits AELs for Class 1 and 1M Class 2 and 2M Class 3R and Class 3B are given in Tables 4 to 9 The values of the correction factors used are given in Table 10 as functions of wavelength emission duration number of pulses and angular subtense a Radiation of a single wavelength A single wavelength laser product with a spectral range of the emission line narrow enough so that the AELs do not change is assigned to a class when the accessible laser radiation measured under the conditions appropriate to that class exceeds the AEL of all lower classes but does not exceed that of the class assigned b Radiation of multiple wavelengths 1 A laser product emitting two or more wavelengths in spectral regions shown as additive in Table 2 is assigned to a class when the sum of the ratios of the accessible laser radiation measured under the conditions appropriate to that class to the AELs of those wavelengths is greater than unity for all lower classes but does not exceed unity for the class assigned 2 A laser product emitting two or more wavelengths not shown as additive in Table 2 is assigned
119. lly the accessible emission of a Class 2M product exceeds the AEL of Class 2 for either condition 1 or condition 2 However it may also be classified as Class 2M when it exceeds the AEL of Class 2 for both condition 1 and condition 2 If the accessible emission exceeds the AEL of Class 3B as determined with a 3 5 mm diameter aperture placed at the closest point of human access an additional warning regarding a potential skin hazard is to be given see 5 3 NOTE 3 It is possible that a Class 2M laser product with a highly diverging beam can produce high enough irradiance levels near to or in contact with the source for instance a fibre tip so that skin injury is possible Class 3R 3B If the level of radiation as determined according to 9 3 for condition 1 condition 2 and condition 3 is less than or equal to the AEL of Class 3R or Class 3B the laser product is assigned to Class 3R or Class 3B respectively See also Note below first paragraph of 8 3 Class 4 If the level of radiation as determined according to 9 3 either for condition 1 or condition 2 or condition 3 exceeds the AEL for Class 3B the product shall be assigned to Class 4 45 9r Table 4 Accessible emission limits for Class 1 and Class 1M laser products and Cg 1 2 Wave length A nm Emission duration t S 10 13 10 11 to 10 11 to 10 9 10 9 1077 to 10 7 1 8 x 10 5 1 8 x 10 5 to 5 x 10 5 5 x 10 5 to
120. lly induced retinal injury there is no spot size dependence for a stabilized image Unlike thermal injury mechanism the thresholds for photochemical injury are highly wavelength dependent and are exposure dose dependent i e the thresholds decrease inversely with the lengthening of exposure duration Studies of photochemical retinal injury from welding arcs subtending angles of the order of 1 mrad to 1 5 mrad showed typical lesion sizes of the order of 185 um to 200 um corresponding to visual angles of 11 mrad to 12 mrad clearly showing the influence of eye movements during fixation these and other studies of eye movements during fixation led to the derivation of MPEs to protect against photochemical retinal injury These studies also led to MPE irradiance to be specified as being averaged over 11 mrad for exposure durations between 10 s and 100 s Hence sources with an angular subtense less than 11 mrad were treated equally with point type sources and the concept of amin was extended to CW laser viewing This approach was not strictly correct as an irradiance measurement of an 11 mrad source is not equivalent to irradiance averaging over a field of view y of 11 mrad unless the source had a rectangular top hat radiance distribution Hence in this edition of the standard distinction is made between angular subtense of a source and irradiance averaging for photochemical MPE values For viewing times in excess of approximately 30 s to 60 s
121. locks of access panels are overridden 3 20 Class 2 laser product any laser product in the wavelength range from 400 nm to 700 nm which during operation does not permit human access to accessible laser radiation in excess of the accessible emission limits of Class 2 for applicable wavelengths and emission durations see 8 2 and 8 3e NOTE 1 See also the limitations of the Classification scheme in Annex C NOTE 2 As tests for the determination of the classification of the product are limited to tests during operation it may be the case for embedded laser products that depending on the product radiation above the AEL of Class 2 can become accessible during maintenance when interlocks of access panels are overridden 3 21 Class 2M laser product any laser product in the wavelength range from 400 nm to 700 nm which during operation does not permit human access to accessible laser radiation in excess of the accessible emission limits of Class 2 for applicable wavelengths and emission durations see 8 3 e where the level of radiation is measured according to 9 2 h NOTE 1 See also the limitations of the Classification scheme in Annex C NOTE 2 Since the evaluation is with a smaller measurement aperture or at a greater distance from the apparent source than those used for Class 2 laser products the output of a Class 2M product is therefore potentially hazardous when viewed using an optical instrument see 8 2 NOTE 3 As tests for the de
122. lse to determine N and the energies of the individual pulses are added to be compared to the AEL of Tij The energy from any group of pulses or sub group of pulses in a train delivered in any given time shall not exceed the AEL for that time 41 1604 2553 60825 1 IEC 2007 79 Table 3 Times below which pulse groups are summed Wavelength nm 400 lt lt 1 050 18 x 10 6 1050 lt A lt 1400 50 x 10 6 b For varying pulse widths or varying pulse durations The total on time pulse TOTP method shall be used The AEL is determined by the duration of the TOTP which is the sum of all pulse durations within the emission duration or To whichever is smaller Pulses with durations less than 7 are assigned pulse durations of Ti If two or more pulses occur within a duration of Ti these pulse groups are assigned pulse durations of Ti For comparison with the AEL for the corresponding duration all individual pulse energies are added 9 Determination of the accessible emission level 9 1 Tests Tests shall take into account all errors and statistical uncertainties in the measurement process see IEC 61040 and increases in emission and degradation in radiation safety with age Specific user requirements may impose additional tests Tests during operation shall be used to determine the classification of the product Tests during operation maintenance and service shall also be used as appropriate to determine
123. m 47 4 10 VIEWING OPTICS ee 47 4 11 Scanning 333 3 3 3131 313131313131313131 53 49 4 12 Walk in ACCESS EE 49 4 13 Environmental conditions 3 13333 313313 131311 1 1 1 11 RUd 49 4 14 Protection against other 2 2222 6 49 111 111111179 51 7 111 11 9 51 5 2 Glass tand Class m 55 5 3 Class 2 and Class 2M 2222222224 26 57 S Glass 3 Lc 59 5 5 Lm PD C 3333 3 170 0 59 56 5 7 1 0 59 57 Aperture 0 I 59 5 8 Radiation output and standards 2 6 6 59 5 9 Labels for access panels reires 61 5 10 Warning for invisible laser radiation
124. mains the responsibility of the manufacturer to provide the safety information indicated below and to decide which additional information is relevant and therefore shall be provided NOTE The information that is relevant or not relevant depends on the specific product including its intended application and may even be subject to national legislation The following information shall be provided a Adequate instructions for proper assembly maintenance and safe use including clear warnings concerning precautions to avoid possible exposure to hazardous laser radiation and description of the classification limitations if appropriate see Annex C for a description of the classes and possible limitations 1604 2553 60825 1 IEC 2007 65 b An additional warning for Class 1M and 2M laser products For diverging beams this warning shall state that viewing the laser output with certain optical instruments for example eye loupes magnifiers and microscopes within a distance of 100 mm may pose an eye hazard For collimated beams this warning shall state that viewing the laser output with certain optical instruments designed for use at a distance for example telescopes and binoculars may pose an eye hazard For laser radiation levels above the AEL of Class 1 a description of any radiation pattern s emitted from the protective housing during the performance of operation and maintenance procedures Where applicable th
125. minimum area A of the label is given by A L 2 000 where A and L are expressed in square metres and metres respectively This formula applies for distance L less than about 50 m NOTE2 These dimensions are recommended values The label may be of any size necessary to contain the required lettering and border The minimum width of each border dimension go and ga must be 0 06 times the length of the shorter side of the label Figure 2 Explanatory label 5 2 Class 1 and Class 1M Except as permitted in Clause 1 each Class 1 laser product shall have affixed an explanatory label Figure 2 bearing the words CLASS 1 LASER PRODUCT Each Class 1M laser product shall have affixed an explanatory label Figure 2 bearing the words LASER RADIATION DO NOT VIEW DIRECTLY WITH OPTICAL INSTRUMENTS CLASS 1M LASER PRODUCT Instead of the above labels at the discretion of the manufacturer the same statements may be included in the information for the user 30 1604 2553 60825 1 IEC 2007 5 The type of optical instrument which could result in an increased hazard may be added in parenthesis after the word instruments on the Class 1M label The added wording could in particular be BINOCULARS OR TELESCOPES for a laser product with a collimated large diameter beam which is classified 1M because it fails condition 1 see Clause 9 or MAGNIFIERS for a laser product which is classified 1M because it fails cond
126. n this standard D 2 2 Hazards to the eye A brief description of the anatomy of the eye is given in Clause D 1 The eye is specially adapted to receive and transduce optical radiation The pathologies caused by excessive exposures are summarized in Table D 1 Thermal interaction mechanisms are shown in Figure D 2 Lasers emitting ultra violet and far infra red radiation represent a corneal hazard while systems emitting visible and near infra red wavelengths will be transmitted to the retina 85 1604 2553 60825 1 IEC 2007 167 Visible and near infra red laser beams are a special hazard to the eye because the very properties necessary for the eye to be an effective transducer of light result in high radiant exposure being presented to highly pigmented tissues The increase in irradiance from the cornea to the retina is approximately the ratio of the pupil area to that of the retinal image This increase arises because the light which has entered the pupil is focused to a point on the retina The pupil is a variable aperture but the diameter may be as large as 7 mm when maximally dilated in the young eye The retinal image corresponding to such a pupil may be between 10 um and 20 um in diameter With intra ocular scattering and corneal aberrations considered the increase in irradiance between the cornea and the retina is of the order of 2 x 105 Table D 1 Summary of pathological effects associated with excessive
127. nal Electrotechnical Commission IEC is a worldwide organization for standardization comprising all national electrotechnical committees IEC National Committees The object of IEC is to promote international co operation on all questions concerning standardization in the electrical and electronic fields To this end and in addition to other activities IEC publishes International Standards Technical Specifications Technical Reports Publicly Available Specifications PAS and Guides hereafter referred to as IEC Publication s Their preparation is entrusted to technical committees any IEC National Committee interested in the subject dealt with may participate in this preparatory work International governmental and non governmental organizations liaising with the IEC also participate in this preparation IEC collaborates closely with the International Organization for Standardization ISO in accordance with conditions determined by agreement between the two organizations The formal decisions or agreements of IEC on technical matters express as nearly as possible an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense While all reasonable efforts are made to ensure that the technical content of IEC Publications
128. nding position of each label affixed to the product shall be indicated or if provided with the product a statement that such labels could not be affixed to the product but were supplied with the product and a statement of the form and manner in which they were supplied shall be provided A clear indication in the manual of all locations of laser apertures through which laser radiation exceeding the Class 1 AEL is emitted List of controls adjustments and procedures for operation and maintenance including the warning Caution Use of controls or adjustments or performance of procedures other than those specified herein may result in hazardous radiation exposure or alternatively equivalent appropriate warnings In the case of laser products that do not incorporate the laser energy source necessary for laser emission a statement of the compatibility requirements for a laser energy source to ensure safety Purchasing and servicing information Manufacturers of laser products shall provide or cause to be provided the following a b 7 7 1 In all catalogues specification sheets and descriptive brochures the classification of each laser product and any warning shall be stated including those specified by 6 1 b if appropriate To servicing dealers and distributors and to others upon request adequate instructions for service adjustments and service procedures for each laser product model which include clear warn
129. ned to derive a break point in viewing time 72 at which eye movements compensated for the increased theoretical risk of thermal injury for increased retinal exposure durations if the eye were immobilized Because the thermal injury threshold expressed as radiant power entering the eye decreases as the exposure duration t raised to the 0 25 power i e a reduction of only 44 per tenfold increase in duration only moderate increases in the exposed retinal area will compensate for the increased risk for longer viewing times The increasing retinal area of irradiation resulting from greater eye movements with increased viewing time takes longer to compensate for the reduced impact of thermal diffusion in larger extended sources Thus for increasing angular subtense a the break point T increases from 10 s for small sources to 100 s for larger sources Beyond 100 s there is no further increase in risk of thermal injury for small and intermediate size images The specification of limits and measuring conditions attempt to follow these variables with some simplification leading to a conservative determination of risk It is conservatively assumed that retinal thermal injury thresholds vary inversely with retinal image size stabilized between approximately 25 um to 1 mm corresponding to angular sizes of 1 5 mrad to 59 mrad whilst beyond 1 7 mm corres ponding to angular sizes greater than 100 mrad there is no spot size dependence For photochemica
130. ng a time interval of 1 299 792 458 of a second millimetre 10 3 m micrometre 10 6 m nanometre 10 9 m Mass kilogram The mass equal to the mass of the international prototype of the kilogram Time second S The duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state caesium 133 atom Frequency hertz The frequency of a periodic phenomenon equal to one cycle per second Plane angle The plane angle between two radii of a circle which cut off on the circumference an arc equal in length to the radius milliradian 10 3 rad Solid angle steradian The solid angle which having its vertex in the centre of a sphere cuts off an area of the surface of the sphere equal to that of a square with sides of length equal to the radius of the sphere Radiant joule per square nm J m 2 exposure metre Integrated joule per square J m 2 sr 1 1 J m 2 sr 1 radiance metre per steradian watt milliwatt watt per square metro Radiance watt per square metre W m 2 sr 1 1 W m 2 sr 1 per steradian NOTE For convenience multiples and submultiples of units have been included where appropriate Table F 2 Summary of manufacturer s requirements Requirements subclause Classification Class 1 Class 1M Class 2 Class 2M Class 3R Class 3B Class 4 Description of hazard class Annex C Safe under reason ably foreseeable conditions As for Cl
131. not exceed either limit applicable Normally photochemical hazard limits only apply for exposure durations greater than 10 s however for wavelengths between 400 nm and 484 nm and for apparent source sizes between 1 5 mrad and 82 mrad the dual photochemical hazard limit of 100 C4 J m should be applied for exposures greater than or equal to 1 s 400c O3l L Sc809 TA S 6 7 091 UCN 1604 2553 60825 1 IEC 2007 119 Table A 3 Maximum permissible exposure MPE of the skin to laser radiation Wave Exposure time t length a nm 10 9 10 9 to 10 7 10 7 to 10 3 10 3 to 10 10 to 103 103 to 5 6 180 to 302 5 10 302 5 30 J 7 0 2 7 3x1010 W m 2 302 5 to 315 C J m 2 aee to 700 2x1011 W m 200 J m 2 10 25 J m 2 000 W m 700 to 1 400 2x10 C W m 200 C J m 1 1x104 C t025 J m 2 000 C4 W m 2 1 000 W m c 2 600 to 10 1011 W m 2 5 600 10 25 J m 2 For correction factors and units see Table 10 There is only limited evidence about effects for exposures of less than 10 9 s The MPEs for these exposure durations have been derived by maintaining the irradiance applying at 10 s For exposed skin areas greater than 0 1 m2 the MPE is reduced to 100 W m 2 Between 0 01 m and 0 1 m the MPE varies inversely proportional to the irradiated skin area A 2 Limiting apertures An appropriate aper
132. nstance 10 s in Tables 4 to 9 the lower limit applies Where the symbol is used this means less than or equal to Cs is only applicable to pulse durations shorter than 0 25 s b Cis only applicable to pulsed lasers and to CW lasers for thermal retinal limits c The maximum limiting angle of acceptance y shall be equal to but see 8 4 d 52 1604 2553 60825 1 IEC 2007 101 9 3 Measurement geometry 9 3 1 General Three measurement conditions are specified for the determination of the accessible emission Condition 1 and 2 are applied for wavelengths where optically aided viewing may increase the hazard Condition 1 is intended to apply to collimated beams where telescopes and binoculars may increase the hazard and condition 2 is intended to apply to sources with a highly diverging output where the use of microscopes hand magnifiers and eye loupes may increase the hazard Condition 3 applies to the unaided eye For power and energy measurement of scanned laser radiation condition 3 shall be used The most restrictive of the applicable measurement conditions shall be applied If the most restrictive condition is not obvious each applicable condition shall be evaluated The following two evaluation schemes are specified a A simplified default method where the test for classification is performed at a fixed distance relative to a reference point which usually can be easily identified For
133. nuator incorporated in the viewing optics viewport or display screen a means shall be provided to a prevent human access to laser radiation in excess of the AEL for Class 1M when the shutter is opened or the attenuation varied b prevent opening of the shutter or variation of the attenuator when exposure to laser radiation in excess of the AEL for Class 1M is possible 1604 2553 60825 1 IEC 2007 49 4 11 Scanning safeguard Laser products intended to emit scanned radiation and classified on this basis shall not as a result of scan failure or of variation in either scan velocity or amplitude permit human access to laser radiation in excess of the AEL for the assigned class unless exposure of people is not reasonably foreseeable during the time interval between failure and when the scanning safeguard reduces emission to levels below the AEL of the class of the product also see 9 1 4 12 Walk in access If a protective housing is equipped with an access panel which provides walk in access then a means shall be provided so that any person inside the housing can prevent activation of a laser hazard that is equivalent to Class 3B or Class 4 b a warning device shall be situated so as to provide adequate warning of emission of laser radiation equivalent to Class 3R in the wavelength range below 400 nm and above 700 nm or of laser radiation equivalent to Class 3B or Class 4 to any person who might be within
134. oduct safety standard the relevant subclauses of IEC 61010 1 shall apply NOTE Many countries have regulations for the control of harmful substances Contact the appropriate national agency for these requirements 4 14 2 Collateral radiation The protective housing of laser products will normally protect against the hazards of collateral radiation e g ultraviolet visible infrared radiation However if a concern exists that accessible collateral radiation might be hazardous the laser MPE values may be applied to conservatively evaluate this hazard 5 Labelling 5 1 General Each laser product shall carry label s in accordance with the requirements of the following clauses The labels shall be durable permanently affixed legible and clearly visible during operation maintenance or service according to their purpose They shall be so positioned that they can be read without the necessity for human exposure to laser radiation in excess of the AEL for Class 1 Text borders and symbols shall be black on a yellow background except for Class 1 where this colour combination need not be used The wording of labels shown in Clause 5 is recommended but not mandatory Other wording that conveys the same meaning may be substituted If the size or design of the product makes labelling impractical the label shall be included with the user information or on the package NOTE Direct printing or engraving of equivalent labels on the laser produ
135. on Because of the wide ranges possible for the wavelength energy content and pulse characteristics of a laser beam the potential hazards arising in its use vary widely It is impossible to regard lasers as a single group to which common safety limits can apply Annex C describes the hazards associated with the classes and possible limitations e g as may arise from optically aided viewing in more detail 31 1604 2553 60825 1 IEC 2007 71 8 2 Classification responsibilities It is the responsibility of the manufacturer or his agent to provide correct classification of a laser product however see 4 1 The product shall be classified on the basis of that combination of output power s and wavelength s of the accessible laser radiation over the full range of capability during operation at any time after manufacture which results in its allocation to the highest appropriate class A laser product can only be assigned to a particular class when it has met all of the requirements within this Part 1 for that class for example engineering controls labelling and information for the user 8 3 Classification rules For the purpose of classification rules the following ranking of the classes in increasing order of hazard shall be used Class 1 Class 1M Class 2 Class 2M Class 3R Class 3B Class 4 NOTE For classification of a laser product as Class 1M or 2M the use of an aperture specified as condition 3
136. on is altered it becomes their responsibility to ensure the product is correctly classified The correct classification of a laser product may involve calculating the AEL for more than one of the classes listed in 8 3 to determine the correct classification as illustrated in Figures B 1 and B 2 Example AELs for Class 1 are presented in Figures B 3 to B 5 67 1604 2553 60825 1 IEC 2007 131 Start with supplied product output parameters iti Choose class Is laser product Pulsed Is output single HEPES select time pulsed or CW or repetitively base 8 3e 8 3f see NOTE 1 pulsed Determine AEL singie Determine AELs p 7 8 3f see NOTE 1 Choose class Choose class use single Is 4 in the range 400 nm to select time pulse duration 10 nm and do the thermal base 8 3e for time base limits apply Choose the smallest value of AELsingie and AELs pr for comparison with the accessible emission level of a single pulse in box Do multiple pulses occur Yes within the period 7 see Table 3 Note maximum allowed value of N 8 3f Determine AEL for chosen class See NOTE 2 5 Determine T AELs p train AELsingle xN is medsured accessible Choose the smallest value of Choose higher class No emission level less tian RT spe and repeat calculated AEL for P As calculations h lass the accessible emission SNOSEM Class t level of a single pulse Yes Choose low
137. on of the irradiance even though more power may be collected To simulate the risk of optically aided viewing of a collimated beam with binoculars or a telescope the closest distance of approach of 2 m with a 50 mm aperture was assumed based upon the closest distance for clear viewing For the purpose of this standard the shortest accommodation distance of the human eye is set to 100 mm at all wavelengths from 400 nm to 1400nm This was chosen as a compromise because all but a few young people and very few myopics cannot accommodate their eyes to distances of less than 100 mm This distance may be used for the measurement of irradiance in the case of intrabeam viewing see Table 11 For wavelengths of less than 400 nm or more than 1 400 nm the greatest hazard is damage to the lens or the cornea Depending on the wavelength optical radiation is absorbed preferentially or exclusively by the cornea or the lens see Table D 1 For diverging beam sources extended or point type of these wavelengths short distances between the source and the eye should be avoided In the wavelength range from 1 500 nm to 2 600 nm radiation penetrates into the aqueous humour The heating effect is therefore dissipated over a greater volume of the eye and the MPEs are increased for exposures less than 10 s The greatest increase in the MPEs occurs for very short pulse durations and within the wavelength range of 1 500 nm to 1 800 nm where the absorbing volume is gr
138. or duration of the order of 1 h to 3 h or less where repair mechanisms cannot cope with the rate of damage the threshold expressed as a radiant exposure is constant over a wide range of exposure duration The spot size dependence as occurs with thermal effects due to heat diffusion does not exist Non linear effects Short pulsed high peak power i e Q switched or mode locked lasers may give rise to tissue damage with a different combination of induction mechanisms Energy is delivered to the biological target in a very short time and hence a high irradiance is produced The target tissues experience such a rapid rise in temperature that the liquid components of their cells are converted to gas In most cases these phase changes are so rapid that they are explosive and the cells rupture The pressure transients may result from thermal expansion and both may also result in shearing damage to tissues remote from the absorbing layers by bulk physical displacement At sub nanosecond exposures self focusing of the ocular media further concentrates laser energy from a collimated beam and further lowers the threshold between approximately 10 ps and 1 ns Furthermore other non linear optical mechanisms appear to play a role in retinal injury in the sub nanosecond region All of the above described damage mechanisms have been shown to operate in the retina and are reflected in the breakpoints or changes of slope in the safe exposure levels described i
139. ptance need not be restricted to yph NOTE For measurements of single sources where a lt ypp it will not be necessary to measure with a specific well defined angle of acceptance To obtain a well defined angle of acceptance the angle of acceptance can be defined by either imaging the source onto a field stop or by masking off the source see Figures 3 and 4 respectively All other retinal limits For measurement of radiation to be compared to retinal limits other than the photochemical limits the angle of acceptance shall fully encompass the source under consideration i e the angle of acceptance shall be at least as large as the angular subtense of the source a However if a gt the limiting angle of acceptance is Omax 100 mrad Within the wavelength range of 400 nm to 1 400 nm for the evaluation of an apparent source which consists of multiple points the angle of acceptance has to be varied in the range of amin lt y Omax see 8 3 d 58 1604 2553 60825 1 IEC 2007 113 Annex A informative Maximum permissible exposure values A 1 General remarks Accessible emission limits AELs are generally derived from the maximum permissible exposures MPEs MPEs have been included in this annex to provide manufacturers with additional information that can assist in evaluating the safety aspects related to the intended use of their product such as the determination of the NOH
140. quired the safety interlock shall prevent access to accessible emission levels above the applicable AEL in Table 1 when the panel is removed Inadvertent resetting of the interlock shall not in itself restore emission values above the applicable AEL in Table 1 These interlocks shall conform to the requirements in the applicable IEC product safety standard see Clause 1 NOTE The requirements of 9 1 also apply to interlocks i e interlocks need to be failsafe or redundant 4 3 2 f a deliberate override mechanism is provided the manufacturer shall also provide adequate instructions about safe methods of working It shall not be possible to leave the override in operation when the access panel is returned to its normal position The interlock shall be clearly associated with a label conforming to 5 9 2 Use of the override shall give rise to a distinct visible or audible warning whenever the laser is energized or capacitor banks are not fully discharged whether or not the access panel is removed or displaced Visible warnings shall be clearly visible through protective eyewear specifically designed or specified for the wavelength s of the accessible laser radiation 4 4 Remote interlock connector Each Class 3B and Class 4 laser system shall have a remote interlock connector When the terminals of the connector are open circuited the accessible radiation shall not exceed the AEL for Class 1M or Class 2M as applicable 4 5 Manual reset Each
141. rements 400c 93l 1L S2809 16 6 7 091 UCN 1604 2553 60825 1 IEC 2007 193 Annex G informative Overview of associated parts of IEC 60825 The associated parts of IEC 60825 are intended for use in conjunction with the basic standard IEC 60825 1 Each part covers a defined scope and provides additional normative and informative guidance to enable the manufacturer and user to correctly classify and use the product in a safe manner by taking account of the particular conditions of use and competence training of the operator user The information covered may include rationale examples clarification methods labelling and any additional limits and requirements See Table G 1 99 001 Table G 1 Overview of additional data in associated parts of IEC 60825 Part Type Description Product Product Product Safety critical Test Hazard Related No designer supplier user component methods assessment standards supplier 1 Standard Equipment classification and requirements Yes Yes Yes Yes Yes Yes 2 Standard Safety of optical fibre communication systems Yes Yes Yes Yes Yes Yes provides application notes and examples 3 Technical report Guidance for laser displays and shows No No Yes No No Yes 4 Standard Laser guards also addresses ability of high Yes Yes Yes Yes Yes Yes power lasers to remove guard material 5 Technical repor
142. rent source above which the MPEs and AELs are independent of the source size NOTE omax 100 mrad 3 55 maximum output maximum radiant power and where applicable the maximum radiant energy per pulse of the total accessible laser radiation emitted in any direction by a laser product over the full range of operational capability at any time after manufacture NOTE The maximum output is the maximum accessible emission that is used to determine the class of the laser product Since the determination of the accessible emission includes besides other conditions considering single fault conditions see 9 2 the maximum output may exceed the highest output during normal operation 3 56 maximum permissible exposure MPE level of laser radiation to which under normal circumstances persons may be exposed without suffering adverse effects The MPE levels represent the maximum level to which the eye or skin can be exposed without consequential injury immediately or after a long time and are related to the wavelength of the laser radiation the pulse duration or exposure duration the tissue at risk and for visible and near infra red laser radiation in the range 400 nm to 1 400 nm the size of the retinal image Maximum permissible exposure levels are in the existing state of knowledge specified in Annex A 3 57 medical laser product any laser product designed manufactured intended or promoted for purposes of in vivo diagnostic surgical
143. replaced by an organisational safety measure of individualised locks that prevent closure of the door when somebody is inside the housing which does not affect the classification but represents a procedure which achieves the desired level of safety for the user 9 1604 2553 60825 1 IEC 2007 155 In cases where the hazard associated with a Class 3B and Class 4 laser product is limited to within the housing organisational safety measures may be sufficient Similarly for a laser system with no roof or a situation where burn through of the guard may occur after some longer lasting fault organisational safety measures may be sufficient Other examples exist where the hazards associated with Class 3B and Class 4 lasers arise only in specific situations For example consider the situation in which the classification is based on an accessory such as a collimating lens applied to a highly divergent source for low level laser therapy This product may be classified as Class 3B based on the accessory lens being screwed on since this lens produces a potentially hazardous collimated beam However use without the accessory being screwed on which would result in a divergent beam could be safe i e any exposure to the eye would be below the MPE Thus a hazard area would only exist around the laser once the accessory has been screwed on C 3 Limitations of the classification scheme Although the classification tests ar
144. s 0 5 W therefore this laser is classified as Class 3B Example B 3 5 Classify a laser emitting 1 pulses with a pulse repetition frequency of 500 Hz a peak output power of 10 kW at 2 694 nm beam diameter is 5 mm and beam divergence is 0 5 mrad Item f of 8 3 contains details of the requirements for repetitively pulsed lasers which are summarised below The AEL for wavelengths from 400 nm to 106 nm is determined by using the most restrictive of requirements a b and c as appropriate For other wavelengths the AEL is determined by using the most restrictive of requirements a and b Requirement c applies only to the thermal limits not to the photochemical limits Choose Class 3B and assume a 100 s time base Check if multiple pulses can occur within the period T as given in Table 3 For this laser wavelength T 18 x 10 6 s and the actual time between pulses is 1 PRF 2 x 10 s hence multiple pulses do not occur in the period T Following the procedure in 8 3 f a Single pulse exposure Table 9 gives for t 10 s AELgingle 0 03 J b Table 9 gives the AEL for T 100 s as follows AELT 0 5 W Dividing by the PRF gives the equivalent AEL energy per pulse therefore AEL 0 5 PRF 500 1x1073J AEL spt C AEL sp train AELsingle x Cs AELsingie x N25 but N is limited to the number of pulses that occur within the period Ts 10 s fora lt S amin see Table 10 Therefore AEL p train 0 03 x 1
145. se is less than 0 25 s 3 69 radiance quantity defined by the formula do L 2 dA cos0 dO where do is the radiant flux transmitted by an elementary beam passing through the given point and propagating in the solid angle dO containing the given direction dA is the area of a section of that beam containing the given point 0 isthe angle between the normal to that section and the direction of the beam Symbol L SI unit W m 2 sr 1 IEV 845 01 34 modified NOTE This definition is a simplified version of IEV 845 01 34 sufficient for the purpose of this Part 1 In cases of doubt the IEV definition should be followed 3 70 radiant energy time integral of the radiant flux over a given duration At Qa f ddt IEV 845 01 27 Symbol Q SI unit joule J 3 71 radiant exposure at a point on a surface the radiant energy incident on an element of a surface divided by the area of that element H lt 2 eat Symbol H SI unit joule per square metre J m 21 1604 2553 60825 1 IEC 2007 39 3 72 radiant power radiant flux power emitted transferred or received in the form of radiation o 99 dt IEV 845 01 24 Symbol o P SI unit watt W 3 73 reflectance ratio of the reflected radiant power to the incident radiant power in the given conditions IEV 845 04 58 modified Symbol p SI unit 1 3 74 remote interlock connector conne
146. ser products that are viewed with large telescopes Highly divergent beam Class 1 Class 2 or Class 3R laser products that are viewed with magnifiers with large magnification Binoculars or telescopes with magnification of less than x7 In this case for condition 1 the magnification of the angular source a that may be applied see 8 3 c or alternatively the reduction of the angle of acceptance see 9 3 2 b should be equal to the real magnification factor i e less than x7 Scanning beams when viewed with telescopes Double fault conditions that might be likely That is faults where each fault on its own would not result in accessible emission above the AEL but both faults occurring at the same time could When these faults are expected to occur with a relatively high probability then the probability for a double fault might be sufficiently high so that it should be considered during product design 81 1604 2553 60825 1 IEC 2007 159 Annex D informative Biophysical considerations D 1 Anatomy of the eye Figure D 1 provides anatomical details of the human eye Eyebrow A Eyelash Eyelid 2 Sclera white of eye Iris colour of eye Pupil black area Retinal vein I Q Optic disk f c bezi Retinal artery vA Light Blood vessels Cornea glassy front of eye Aqueous humour Lens x re Receptor cells Conjuctiva
147. sible emission is determined where human access is considered as specified in Definition 3 37 The accessible emission is compared with the accessible emission limit Definition 3 3 in order to determine the class of the laser product In the body of the standard whenever the term emission level is used it is to be understood as accessible emission NOTE When the beam diameter is larger than the aperture stop the accessible emission when given in units of Watts or Joules is less than the total emitted power or energy of the laser product When the beam diameter is smaller than the diameter of the limiting aperture the accessible emission when given in units of W m 2 or J m 2 i e as irradiance or radiant exposure averaged over the limiting aperture is smaller than the actual irradiance or radiant exposure of the beam See also aperture stop 3 9 and limiting aperture 3 52 3 3 accessible emission limit AEL the maximum accessible emission permitted within a particular class NOTE Wherever the text refers to emission level not exceeding the AEL or similar wording it is implicit that the accessible emission is determined following the measurement criteria specified in Clause 9 1 1604 2553 60825 1 IEC 2007 19 3 4 administrative control safety measures of a non engineering type such as key supervision safety training of personnel warning notices count down procedures and range safety con
148. ssion level ssessn mmm 79 Oil 333 33 3 31 10 79 9 2 Measurement of laser radiation nennen rennen nnns 81 9 3 Measurement geometry cccccce cece cece cece cee eee e eae e enne eed enn henn tesa ese senes sese nnne 101 Annex A informative Maximum permissible exposure values sseseenee 113 Annex B informative Examples of calculations ssssesssee 127 Annex C informative Description of the classes and potentially associated hazards 147 Annex D informative Biophysical considerations ssssssssseee e 159 Annex E informative MPEs and AELs expressed as radiance 2 4 esteetteneen 179 Annex F informative Summary tables sssssssssssssssesseeee nennen nen nennen nnns 187 Annex G informative Overview of associated parts of IEC 60825 2222 666 193 slut 197 Figure 1 Warning label Hazard symbol sssssssssseeeesee nennen nennen nnn 53 Figure 2 Explanatory label 3 111 10 55 Figure 3 Measurement set up to limit angle of acceptance by imaging the apparent source onto the plane of the field stop ssssssssssssssssssnne mene ne renes nnns 105 Figure 4 Measurement set up to limit angle of acceptance by placing a circular aperture or a mask serving as field stop close to the apparent sour
149. stance 2400 1400 50 200 7 70 7 w Tx 1 fort lt 0 35s 3 8 gt 1400 to 4000 condition 3 2 000 7 70 1 pe ES S 1 fort lt 0 35s gt 4000 to 105 1 5 8 8 for0 35s lt t lt 10s 3 5 for t2 10 s tins 2105101009 10 106 11 NOTE The descriptions below the 1 are V cases for information only and are not to be exclusive Table 12 Reference points Type of product Reference point Semiconductor emitters LEDs laser diodes Physical location of the emitting chip superluminescent diodes Scanned emission including scanned line lasers Scanning vertex pivot point of the scanning beam Line laser Focal point of the line vertex of the fan angle Output of fibre Fibre tip Totally diffused sources Surface of diffuser Others Beam waist NOTE If the reference point is located inside of the protective housing i e is not accessible at a distance from the closest point of human access further than the measurement distance specified in Table 11 the measurement must be carried out at the closest point of human access 9 3 3 Evaluation condition for extended sources For wavelengths in the retinal hazard range 400 nm to 1 400 nm the accessible emission and the AEL for classification shall be determined at the most restrictive position when a value of Cg larger than 1 is considered for determination of the AEL or when a limited angle of acceptance is consi
150. stem and optical elements placed in the beam when this is considered as relevant it is recommended that the different NOHD values are given for the different attachments or beam delivery systems If there is a variable beam divergence the NOHD could be given for some selected values of divergence When an MPE and NOHD value is stated the assumed exposure duration for the determination of these values shall also be stated For collimated beam Class 1M and Class 2M lasers the extended NOHD ENOHD shall be stated where appropriate and relevant NOTE Specific information on the NOHD is typically not required for collimated beams that are to be used indoors In that case it is usually sufficient to give only an indication of the extent of the range where the MPE can be exceeded Where appropriate information for the selection of eye protection This shall include the required optical density as well as irradiance or radiation exposure levels that might be incident on the surface of the eye protection equipment so that resistance levels can be determined NOTE Many countries have regulations and standards for personal protective equipment Contact the appropriate national agency for these requirements 35 1604 2553 60825 1 IEC 2007 67 9 6 2 Legible reproductions colour optional of all required labels and hazard warnings to be affixed to the laser product or provided with the laser product The correspo
151. sts that accessible collateral radiation might be hazardous the laser MPE values may be applied to conservatively evaluate this potential hazard The MPE values are not applicable to intentional human exposure to laser radiation for the purpose of medical or cosmetic aesthetic treatment NOTE 5 Annexes A to H have been included for purposes of general guidance and to illustrate many typical cases However the annexes are not regarded as definitive or exhaustive and reference should always be made to the appropriate clause s in the normative part of this document The objectives of this part of IEC 60825 are the following e to introduce a system of classification of lasers and laser products according to their degree of optical radiation hazard in order to aid hazard evaluation and to aid the determination of user control measures e to establish requirements for the manufacturer to supply information so that proper precautions can be adopted e to ensure through labels and instructions adequate warning to individuals of hazards associated with accessible radiation from laser products e to reduce the possibility of injury by minimizing unnecessary accessible radiation and to give improved control of the laser radiation hazards through protective features 2 IEC Guide 104 1 997 The preparation of safety publications and the use of basic safety publications and group safety publications ii 1604 2553 60825 1
152. t Manufacturer s checklist for IEC 60825 1 Yes Yes No Yes No No suitable for use in a safety report 6 Technical specification withdrawn 7 Technical specification withdrawn 8 Technical report Guidelines for the safe use of medical laser No No Yes No No No IEC 60601 2 22 equipment 9 Technical report Compilation of maximum permissible exposure No No Yes No Yes Yes to incoherent optical radiation broadband Sources 10 Technical report Laser safety application guidelines and explanatory Yes Yes No No Yes No ISO 13694 notes 12 Standard Safety of free space optical communication Yes Yes Yes Yes Yes Yes systems used for transmission of information 14 Technical report A user s guide No Yes Yes No No Yes NOTE This table is intended to provide an indication of content see text of the particular standard for complete requirements discussion by working groups and may not be formally published Some parts listed above may be under 400c O3l 1 682809 S6l 6 7 091 UCN 1604 2553 60825 1 IEC 2007 197 Bibliography IEC 60027 1 Letter symbols to be used in electrical technology Part 1 General IEC 60065 Audio video and similar apparatus Safety requirements IEC 60079 all parts Electrical apparatus for explosive gas atmospheres IEC 60079 0 2004 Electrical apparatus for explosive gas atmospheres Part 0 General requirements IEC 60204
153. termination of the classification of the product are limited to tests during operation it may be the case for embedded laser products that depending on the product radiation above the AEL of Class 2M can become accessible during maintenance when interlocks of access panels are overridden 3 22 Class 3R and Class 3B laser products any laser product which during operation permits human access to laser radiation in excess of the accessible emission limits of Class 1 and Class 2 as applicable but which does not permit human access to laser radiation in excess of the accessible emission limits of Classes 3R and 3B respectively for any emission duration and wavelength see 8 2 NOTE 1 See also the limitations of the Classification scheme in Annex C NOTE 2 Class 1M and Class 2M products may have outputs above or below the AEL of Class 3R depending on their optical characteristics 14 1604 2553 60825 1 IEC 2007 25 3 23 Class 4 laser product any laser product which permits human access to laser radiation in excess of the accessible emission limits of Class 3B see 8 2 3 24 collateral radiation any electromagnetic radiation within the wavelength range between 180 nm and 1 mm except laser radiation emitted by a laser product as a result of or physically necessary for the operation of a laser 3 25 collimated beam beam of radiation with very small angular divergence or convergence 3 26 continuous wa
154. the centre of the macula the macula is responsible for detailed vision Section D is the structure of the retina as seen in the cut surface of Figure D 1 B but magnified several hundreds times larger than life The retina consists of a series of layers of nerve cells which overlie the photosensitive rod and cone cells i e light falling on the retinal surface has to pass through the layers of nerve cells before it reaches the photosensitive cells Underneath the layer of rods and cones is a layer of the pigment epithelium that contains a brownish black pigment melanin and beneath this is a layer of fine blood vessels the choriocapillaris The final absorbing layer is the choroid which contains both pigmented cells and blood vessels Section E is the structure of the foveal region magnified several hundreds times Here only cones are present The nerve cells are displaced radially away from this area of most acute vision The macular pigment which absorbs strongly from 400 nm to 500 nm is located in the fibre layer of Henle D 2 The effects of laser radiation on biological tissue D 2 1 General The mechanism by which laser radiation induces damage is similar for all biological systems and may involve interactions of heat thermoacoustic transients photochemical processes and non linear effects The degree to which any of these mechanisms is responsible for damage may be related to certain physical parameters of the irradiating source t
155. the Table E 1 or on the Figure E 1 cannot exceed Class 1 accessible emission limits AELs regardless of the optics placed in front of a diffused source E 2 Radiance values The radiance values in Table E 1 are based upon the IEC ICNIRP MPE levels As MPEs are generally expressed in terms of radiant exposure J m 2 or irradiance W m 2 it was necessary to convert the MPE values to radiance W m 2 sr 1 The radiance values are then plotted as a function of wavelength See Clause E 3 Table E 1 presents radiance permissible exposure values as a function of wavelength for a 100 exposure duration where subtends an angle of greater than or equal to 100 mrad The most restrictive limits photochemical or thermal are listed Retinal photochemical hazard limits are in italics style Radiances MPE values of a 100 s exposure of a source subtending a 100 mrad angle 250 000 1 200 000 Sr 2 150 000 100 000 Radiance W m 50 000 400 500 600 700 800 900 1 000 1100 1 200 Wavelength nm IEC 423 07 Figure E 1 Radiance as a function of wavelength 92 60825 1 IEC 2007 Table E 1 Maximum radiance of a diffused source for Class 1 181 Wavelength Radiance Radiance nm W m 2 sr 1 W cm 2 sr 1 430 10 000 1 00 450 10 000 1 00 460 15 848 1 58 465 19 952 2 00 470 25 119 2 51 480 39
156. the housing c where walk in access during operation is intended or reasonably foreseeable emission of laser radiation that is equivalent to Class 3B or Class 4 while someone is present inside the enclosure of a Class 1 Class 2 or Class 3H product shall be prevented by engineering means NOTE Methods to prevent human access to radiation when persons are inside the protective housing may include pressure sensitive floor mats infrared detectors etc 4 13 Environmental conditions The laser product shall meet the safety requirements defined in this standard under all expected operating conditions appropriate to the intended use of the product Factors to be considered shall include climatic conditions e g temperature relative humidity vibration and shock If no provisions are made in the product safety standard the relevant subclauses of IEC 61010 1 shall apply NOTE Requirements related to electromagnetic susceptibility are under consideration 4 14 Protection against other hazards 4 14 1 Non optical hazards The requirements of the relevant product safety standard shall be fulfilled during operation and in the event of a single fault for the following electrical hazards excessive temperature spread of fire from the equipment sound and ultrasonics harmful substances explosion 21 1604 2553 60825 1 IEC 2007 51 If no provisions are included in the pr
157. trols 3 5 alpha min Q min see angular subtense and minimum angular subtense see 3 7 and 3 58 3 6 angle of acceptance plane angle within which a detector will respond to optical radiation usually measured in radians This angle of acceptance may be controlled by apertures or optical elements in front of the detector see Figure 3 and 4 The angle of acceptance is also sometimes referred to as the field of view Symbol y 3 7 angular subtense of the apparent source Qa angle subtended by an apparent source as viewed from a point in space as shown in Figure 3 NOTE 1 The location and angular subtense of the apparent source depends on the viewing position in the beam see 3 11 NOTE 2 The angular subtense of an apparent source is applicable in this Part 1 only in the wavelength range from 400 nm to 1 400 nm the retinal hazard region NOTES The angular subtense of the source should not be confused with the divergence of the beam The angular subtense of the source can not be larger than the divergence of the beam but it is usually smaller than the divergence of the beam 3 8 aperture any opening in the protective housing or other enclosure of a laser product through which laser radiation is emitted thereby allowing human access to such radiation See also limiting aperture 3 52 3 9 aperture stop opening serving to define the area over which radiation is measured 3 10 apparent source for a given evaluation
158. ture should be used for all measurements and calculations of exposure values This is the limiting aperture and is defined in terms of the diameter of a circular area over which the irradiance or radiant exposure is to be averaged Values for the limiting apertures are shown in Table A 4 For repetitively pulsed laser exposures within the spectral range between 1 400 nm and 105 nm the 1 mm aperture is used for evaluating the hazard from an individual pulse whereas the 3 5 mm aperture is applied for evaluating the MPE applicable for exposures greater than 10 s NOTE The values of ocular exposures in the wavelength range 400 nm to 1 400 nm are measured over a 7 mm diameter aperture pupil The MPE must not be adjusted to take into account smaller pupil diameters Table A 4 Aperture diameters for measuring laser irradiance and radiant exposure Spectral region Aperture diameter for nm mm for 1 lt 0 35 gt 1 400 to 105 m for 0 35s t 10s 3 5 fo t210s 0 3 5 n NOTE For multiple pulse exposures refer to Clause A 3 62 1604 2553 60825 1 IEC 2007 121 A 3 Repetitively pulsed or modulated lasers The following methods should be used to determine the MPE to be applied to exposures to repetitively pulsed radiation The exposure from any group of pulses or sub group of pulses in a train delivered in any given time should not exceed the MPE for that time The MPE for ocular exposure
159. up on a ladder cleaning an exit window Another example is that whilst a scan pattern might be safe a hazard may arise if the beam reverts to the non scanning mode In addition for Class 4 laser products there is a NOHD associated with diffuse reflections although this NOHD is likely to be quite limited in extent The characterisation of the hazard associated with a particular laser and application is part of a risk assessment Classification tests are designed to be rather worst case and restrictive in order to ensure that a low class e g Class 1 product does not present a hazard to the eye or skin even in reasonably foreseeable worst case situations Consequently a Class 3B or Class 4 product can still be designed in such a way that it can be considered safe for its intended use and normal operation since the hazard only becomes accessible in worst case situations For instance the product could feature a protective housing which complies with IEC 60825 4 but fails to be an embedded Class 1 laser product because of the following reasons The housing fails the test according to this Part 1 for an extended period whereas for machines according to IEC 60825 4 a shorter evaluation time may be used lt has no top cover but would be considered safe for an environment where no persons are present above the guard It does not feature an automatic detection of walk in access However in a controlled environment this can be
160. uration s IEC 419 07 Figure B 4 AEL for Class 1 ultra violet laser products for emission durations from 10 9 to 10 s at selected wavelengths Fi 1604 2553 60825 1 IEC 2007 139 10 c E 500 nm 700 nm 10 L 475 nm gt E gt C 400 nm 450 nm D Ls 5 10 b E S g L C 10 E 10 10 E F 1050 nm 1 150 nm 6 10 E900nm C 400 nm 700 nm 107 1 11m 1 nm ar im or ium ag nim or rin ot trim ot rind ar comm ot p pir 9 8 6 10 40 107 49 105 10 30 10 107 109 10 10 10 Emission duration s IEC 420 07 Figure B 5 AEL for Class 1 visible and selected infra red laser products case Cg 1 B 3 Examples Example B 3 1 Classify a CW HeNe laser A 633 nm with an output power of 50 mW beam diameter 3 mm and beam divergence 1 mrad Solution From the beam characteristics it can be inferred that this is a well collimated point source where a lt a j 1 5 mrad Because of the small beam diameter and divergence angle the full beam power will pass through a 7 mm aperture and hence measurement Conditions 1 2 and 3 will give the same accessible emission level Choose a classification class and select an appropriate time base see 8 3e Choose Class 3B and a time base of 100 s Although the laser output is in the visible wavelength range 400 nm to 700 nm a time base of 0 25 s is not allowed for Class
161. uring interlock override and be in close proximity to the opening created by the removal of the protective housing This label shall bear the words specified in items a to f of 5 9 1 as applicable with the introduction of an additional line positioned after the first line with the following words AND INTERLOCKS DEFEATED 5 10 Warning for invisible laser radiation In many cases the wording prescribed for labels in Clause 5 includes the phrase LASER RADIATION If the output of the laser is outside the wavelength range from 400 nm to 700 nm this shall be modified to read INVISIBLE LASER RADIATION or if the output is at wavelengths both inside and outside this wavelength range to read VISIBLE AND INVISIBLE LASER RADIATION If a product is classified on the basis of the level of visible laser radiation and also emits in excess of the AEL of Class 1 at invisible wavelengths the label shall include the words VISIBLE AND INVISIBLE LASER RADIATION in lieu of LASER RADIATION 5 11 Warning for visible laser radiation The wording LASER RADIATION for labels in Clause 5 may be modified to read LASER LIGHT if the output of the laser product is in the visible wavelength range from 400 nm to 700 nm 6 Other informational requirements 6 1 Information for the user Manufacturers of laser products shall provide or see to the provision of user instructions or an operation manual that contains all relevant safety information It re
162. ve in this Part 1 a laser operating with a continuous output for a duration equal to or greater than 0 25 s is regarded as a CW laser 3 27 defined beam path intended path of a laser beam within the laser product 3 28 demonstration laser product any laser product designed manufactured intended or promoted for purposes of demon stration entertainment advertising display or artistic composition The term demonstration laser product does not apply to laser products which are designed and intended for other applications although they may be used for demonstrating those applications 3 29 diffuse reflection change of the spatial distribution of a beam of radiation by scattering in many directions by a surface or medium A perfect diffuser destroys all correlation between the directions of the incident and emergent radiation IEV 845 04 47 modified 3 30 embedded laser product in this Part 1 a laser product which because of engineering features limiting the accessible emission has been assigned a class number lower than the inherent capability of the laser incorporated NOTE The laser which is incorporated in the embedded laser product is called the embedded laser 3 31 emission duration temporal duration of a pulse of a train or series of pulses or of continuous operation during which human access to laser radiation could occur as a result of operation maintenance or servicing of a laser product

มอก. 1604–2553 - ราชกิจจานุเบกษา

Contents

Download Pdf Manuals

Related Search

Related Contents

มอก. 1604&ndash;2553 - ราชกิจจานุเบกษา

Contents

Download Pdf Manuals

Related Search

Related Contents

มอก. 1604–2553 - ราชกิจจานุเบกษา