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The biophysically relevant exposure values to optical radiation can be determined with the formulae below. The formulae to be used depend on the range of radiation emitted by the source and the results should be compared with the corresponding exposure limit values indicated in Table 1.1. More than one exposure value and corresponding exposure limit can be relevant for a given source of optical radiation.
Numbering (a) to (o) refers to corresponding rows of Table 1.1.
For the purposes of this Directive, the formulae above can be replaced by the following expressions and the use of discrete values as set out in the following tables:
Notes:
spectral irradiance or spectral power density: the radiant power incident per unit area upon a surface, expressed in watts per square metre per nanometre [W m-2 nm-1]; values of Eλ (λ, t) and Eλ come from measurements or may be provided by the manufacturer of the equipment;
effective irradiance (UV range): calculated irradiance within the UV wavelength range 180 to 400 nm spectrally weighted by S (λ), expressed in watts per square metre [W m-2];
radiant exposure: the time integral of the irradiance, expressed in joules per square metre [J m-2];
effective radiant exposure: radiant exposure spectrally weighted by S (λ), expressed in joules per square metre [J m-2];
total irradiance (UVA): calculated irradiance within the UVA wavelength range 315 to 400 nm, expressed in watts per square metre [W m-2];
radiant exposure: the time and wavelength integral or sum of the irradiance within the UVA wavelength range 315 to 400 nm, expressed in joules per square metre [J m-2];
spectral weighting taking into account the wavelength dependence of the health effects of UV radiation on eye and skin, (Table 1.2) [dimensionless];
time, duration of the exposure, expressed in seconds [s];
wavelength, expressed in nanometres [nm];
bandwidth, expressed in nanometres [nm], of the calculation or measurement intervals;
spectral radiance of the source expressed in watts per square metre per steradian per nanometre [W m-2 sr -1 nm-1];
spectral weighting taking into account the wavelength dependence of the thermal injury caused to the eye by visible and IRA radiation (Table 1.3) [dimensionless];
effective radiance(thermal injury): calculated radiance spectrally weighted by R (λ) expressed in watts per square metre per steradian [W m-2 sr -1];
spectral weighting taking into account the wavelength dependence of the photochemical injury caused to the eye by blue light radiation (Table 1.3) [dimensionless];
effective radiance(blue light): calculated radiance spectrally weighted by B (λ), expressed in watts per square metre per steradian [W m-2 sr -1];
effective irradiance (blue light): calculated irradiance spectrally weighted by B (λ) expressed in watts per square metre [W m-2];
total irradiance (thermal injury): calculated irradiance within the infrared wavelength range 780 nm to 3 000 nm expressed in watts per square metre [W m-2];
total irradiance (visible, IRA and IRB): calculated irradiance within the visible and infrared wavelength range 380 nm to 3 000 nm, expressed in watts per square metre [W m-2];
radiant exposure: the time and wavelength integral or sum of the irradiance within the visible and infrared wavelength range 380 to 3 000 nm, expressed in joules per square metre (J m-2);
angular subtense: the angle subtended by an apparent source, as viewed at a point in space, expressed in milliradians (mrad). Apparent source is the real or virtual object that forms the smallest possible retinal image.
Exposure limit values for non-coherent optical radiation
S (λ) [dimensionless], 180 nm to 400 nm
λ in nm | S (λ) | λ in nm | S (λ) | λ in nm | S (λ) | λ in nm | S (λ) | λ in nm | S (λ) |
---|---|---|---|---|---|---|---|---|---|
180 | 0,012 | 228 | 0,1737 | 276 | 0,9434 | 324 | 0,00052 | 372 | 0,000086 |
181 | 0,0126 | 229 | 0,1819 | 277 | 0,9272 | 325 | 0,0005 | 373 | 0,000083 |
182 | 0,0132 | 230 | 0,19 | 278 | 0,9112 | 326 | 0,000479 | 374 | 0,00008 |
183 | 0,0138 | 231 | 0,1995 | 279 | 0,8954 | 327 | 0,000459 | 375 | 0,000077 |
184 | 0,0144 | 232 | 0,2089 | 280 | 0,88 | 328 | 0,00044 | 376 | 0,000074 |
185 | 0,0151 | 233 | 0,2188 | 281 | 0,8568 | 329 | 0,000425 | 377 | 0,000072 |
186 | 0,0158 | 234 | 0,2292 | 282 | 0,8342 | 330 | 0,00041 | 378 | 0,000069 |
187 | 0,0166 | 235 | 0,24 | 283 | 0,8122 | 331 | 0,000396 | 379 | 0,000066 |
188 | 0,0173 | 236 | 0,251 | 284 | 0,7908 | 332 | 0,000383 | 380 | 0,000064 |
189 | 0,0181 | 237 | 0,2624 | 285 | 0,77 | 333 | 0,00037 | 381 | 0,000062 |
190 | 0,019 | 238 | 0,2744 | 286 | 0,742 | 334 | 0,000355 | 382 | 0,000059 |
191 | 0,0199 | 239 | 0,2869 | 287 | 0,7151 | 335 | 0,00034 | 383 | 0,000057 |
192 | 0,0208 | 240 | 0,3 | 288 | 0,6891 | 336 | 0,000327 | 384 | 0,000055 |
193 | 0,0218 | 241 | 0,3111 | 289 | 0,6641 | 337 | 0,000315 | 385 | 0,000053 |
194 | 0,0228 | 242 | 0,3227 | 290 | 0,64 | 338 | 0,000303 | 386 | 0,000051 |
195 | 0,0239 | 243 | 0,3347 | 291 | 0,6186 | 339 | 0,000291 | 387 | 0,000049 |
196 | 0,025 | 244 | 0,3471 | 292 | 0,598 | 340 | 0,00028 | 388 | 0,000047 |
197 | 0,0262 | 245 | 0,36 | 293 | 0,578 | 341 | 0,000271 | 389 | 0,000046 |
198 | 0,0274 | 246 | 0,373 | 294 | 0,5587 | 342 | 0,000263 | 390 | 0,000044 |
199 | 0,0287 | 247 | 0,3865 | 295 | 0,54 | 343 | 0,000255 | 391 | 0,000042 |
200 | 0,03 | 248 | 0,4005 | 296 | 0,4984 | 344 | 0,000248 | 392 | 0,000041 |
201 | 0,0334 | 249 | 0,415 | 297 | 0,46 | 345 | 0,00024 | 393 | 0,000039 |
202 | 0,0371 | 250 | 0,43 | 298 | 0,3989 | 346 | 0,000231 | 394 | 0,000037 |
203 | 0,0412 | 251 | 0,4465 | 299 | 0,3459 | 347 | 0,000223 | 395 | 0,000036 |
204 | 0,0459 | 252 | 0,4637 | 300 | 0,3 | 348 | 0,000215 | 396 | 0,000035 |
205 | 0,051 | 253 | 0,4815 | 301 | 0,221 | 349 | 0,000207 | 397 | 0,000033 |
206 | 0,0551 | 254 | 0,5 | 302 | 0,1629 | 350 | 0,0002 | 398 | 0,000032 |
207 | 0,0595 | 255 | 0,52 | 303 | 0,12 | 351 | 0,000191 | 399 | 0,000031 |
208 | 0,0643 | 256 | 0,5437 | 304 | 0,0849 | 352 | 0,000183 | 400 | 0,00003 |
209 | 0,0694 | 257 | 0,5685 | 305 | 0,06 | 353 | 0,000175 | ||
210 | 0,075 | 258 | 0,5945 | 306 | 0,0454 | 354 | 0,000167 | ||
211 | 0,0786 | 259 | 0,6216 | 307 | 0,0344 | 355 | 0,00016 | ||
212 | 0,0824 | 260 | 0,65 | 308 | 0,026 | 356 | 0,000153 | ||
213 | 0,0864 | 261 | 0,6792 | 309 | 0,0197 | 357 | 0,000147 | ||
214 | 0,0906 | 262 | 0,7098 | 310 | 0,015 | 358 | 0,000141 | ||
215 | 0,095 | 263 | 0,7417 | 311 | 0,0111 | 359 | 0,000136 | ||
216 | 0,0995 | 264 | 0,7751 | 312 | 0,0081 | 360 | 0,00013 | ||
217 | 0,1043 | 265 | 0,81 | 313 | 0,006 | 361 | 0,000126 | ||
218 | 0,1093 | 266 | 0,8449 | 314 | 0,0042 | 362 | 0,000122 | ||
219 | 0,1145 | 267 | 0,8812 | 315 | 0,003 | 363 | 0,000118 | ||
220 | 0,12 | 268 | 0,9192 | 316 | 0,0024 | 364 | 0,000114 | ||
221 | 0,1257 | 269 | 0,9587 | 317 | 0,002 | 365 | 0,00011 | ||
222 | 0,1316 | 270 | 1,0 | 318 | 0,0016 | 366 | 0,000106 | ||
223 | 0,1378 | 271 | 0,9919 | 319 | 0,0012 | 367 | 0,000103 | ||
224 | 0,1444 | 272 | 0,9838 | 320 | 0,001 | 368 | 0,000099 | ||
225 | 0,15 | 273 | 0,9758 | 321 | 0,000819 | 369 | 0,000096 | ||
226 | 0,1583 | 274 | 0,9679 | 322 | 0,00067 | 370 | 0,000093 | ||
227 | 0,1658 | 275 | 0,96 | 323 | 0,00054 | 371 | 0,00009 |
B (λ), R (λ) [dimensionless], 380 nm to 1 400 nm
λ in nm | B (λ) | R (λ) |
---|---|---|
300 ≤ λ < 380 | 0,01 | — |
380 | 0,01 | 0,1 |
385 | 0,013 | 0,13 |
390 | 0,025 | 0,25 |
395 | 0,05 | 0,5 |
400 | 0,1 | 1 |
405 | 0,2 | 2 |
410 | 0,4 | 4 |
415 | 0,8 | 8 |
420 | 0,9 | 9 |
425 | 0,95 | 9,5 |
430 | 0,98 | 9,8 |
435 | 1 | 10 |
440 | 1 | 10 |
445 | 0,97 | 9,7 |
450 | 0,94 | 9,4 |
455 | 0,9 | 9 |
460 | 0,8 | 8 |
465 | 0,7 | 7 |
470 | 0,62 | 6,2 |
475 | 0,55 | 5,5 |
480 | 0,45 | 4,5 |
485 | 0,32 | 3,2 |
490 | 0,22 | 2,2 |
495 | 0,16 | 1,6 |
500 | 0,1 | 1 |
500 < λ ≤ 600 | 100,02·(450 - λ) | 1 |
600 < λ ≤ 700 | 0,001 | 1 |
700 < λ ≤ 1 050 | — | 100,002 · (700 - λ) |
1 050 < λ ≤ 1 150 | — | 0,2 |
1 150 < λ ≤ 1 200 | — | 0,2· 100,02·(1 150 - λ) |
1 200 < λ ≤ 1 400 | — | 0,02 |
The biophysically relevant exposure values to optical radiation can be determined with the formulae below. The formulae to be used depend on the wavelength and duration of radiation emitted by the source and the results should be compared with the corresponding exposure limit values indicated in the Tables 2.2 to 2.4. More than one exposure value and corresponding exposure limit can be relevant for a given source of laser optical radiation.U.K.
Coefficients used as calculation tools within the Tables 2.2 to 2.4 are listed in Table 2.5 and corrections for repetitive exposure are listed in Table 2.6.
Notes:
power expressed in watt [W];
surface expressed in square metres [m2];
irradiance or power density: the radiant power incident per unit area upon a surface, generally expressed in watts per square metre [W m-2]. Values of E(t), E come from measurements or may be provided by the manufacturer of the equipment;
radiant exposure: the time integral of the irradiance, expressed in joules per square metre [J m-2];
time, duration of the exposure, expressed in seconds [s];
wavelength, expressed in nanometres [nm];
limiting cone angle of measurement field-of-view expressed in milliradians [mrad];
measurement field of view expressed in milliradians [mrad];
angular subtense of a source expressed in milliradians [mrad];
limiting aperture: the circular area over which irradiance and radiant exposure are averaged;
integrated radiance: the integral of the radiance over a given exposure time expressed as radiant energy per unit area of a radiating surface per unit solid angle of emission, in joules per square metre per steradian [J m-2 sr -1].
Wavelength [nm]λ | Radiation range | Affected organ | Hazard | Exposure limit value table |
---|---|---|---|---|
180 to 400 | UV | eye | photochemical damage and thermal damage | 2.2, 2.3 |
180 to 400 | UV | skin | erythema | 2.4 |
400 to 700 | visible | eye | retinal damage | 2.2 |
400 to 600 | visible | eye | photochemical damage | 2.3 |
400 to 700 | visible | skin | thermal damage | 2.4 |
700 to 1 400 | IRA | eye | thermal damage | 2.2, 2.3 |
700 to 1 400 | IRA | skin | thermal damage | 2.4 |
1 400 to 2 600 | IRB | eye | thermal damage | 2.2 |
2 600 to 106 | IRC | eye | thermal damage | 2.2 |
1 400 to 106 | IRB, IRC | eye | thermal damage | 2.3 |
1 400 to 106 | IRB, IRC | skin | thermal damage | 2.4 |
Parameter as listed in ICNIRP | Valid spectral range (nm) | Value |
---|---|---|
CA | λ < 700 | CA = 1,0 |
700 — 1 050 | CA = 10 0,002(λ - 700) | |
1 050 — 1 400 | CA = 5,0 | |
CB | 400 — 450 | CB = 1,0 |
450 — 700 | CB = 10 0,02(λ - 450) | |
CC | 700 — 1 150 | CC = 1,0 |
1 150 — 1 200 | CC = 10 0,018(λ - 1 150) | |
1 200 — 1 400 | CC = 8,0 | |
T1 | λ < 450 | T1 = 10 s |
450 — 500 | T1 = 10 · [10 0,02 (λ - 450)] s | |
λ > 500 | T1 = 100 s |
Parameter as listed in ICNIRP | Valid for biological effect | Value |
---|---|---|
αmin | all thermal effects | αmin = 1,5 mrad |
Parameter as listed in ICNIRP | Valid angular range (mrad) | Value |
---|---|---|
CE | α < αmin | CE = 1,0 |
αmin < α < 100 | CE = α/αmin | |
α > 100 | CE = α2/(αmin · αmax) mrad with αmax = 100 mrad | |
T2 | α < 1,5 | T2 = 10 s |
1,5 < α < 100 | T2 = 10 · [10 (α - 1,5) / 98,5] s | |
α > 100 | T2 = 100 s |
Parameter as listed in ICNIRP | Valid exposure time range (s) | Value |
---|---|---|
γ | t ≤ 100 | γ = 11 [mrad] |
100 < t < 104 | γ = 1,1 t 0,5 [mrad] | |
t > 104 | γ = 110 [mrad] |
Each of the following three general rules should be applied to all repetitive exposures as occur from repetitively pulsed or scanning laser systems:
The exposure from any single pulse in a train of pulses shall not exceed the exposure limit value for a single pulse of that pulse duration.
The exposure from any group of pulses (or sub-group of pulses in a train) delivered in time t shall not exceed the exposure limit value for time t.
The exposure from any single pulse within a group of pulses shall not exceed the single-pulse exposure limit value multiplied by a cumulative-thermal correction factor Cp=N-0,25, where N is the number of pulses. This rule applies only to exposure limits to protect against thermal injury, where all pulses delivered in less than Tmin are treated as a single pulse.
Parameter | Valid spectral range (nm) | Value |
---|---|---|
Tmin | 315 < λ ≤ 400 | Tmin = 10 -9 s (= 1 ns) |
400 < λ ≤ 1 050 | Tmin = 18· 10 -6 s (= 18 μs) | |
1 050 < λ ≤ 1 400 | Tmin = 50· 10 -6 s (= 50 μs) | |
1 400 < λ ≤ 1 500 | Tmin = 10 -3 s (= 1 ms) | |
1 500 < λ ≤ 1 800 | Tmin = 10 s | |
1 800 < λ ≤ 2 600 | Tmin = 10 -3 s (= 1 ms) | |
2 600 < λ ≤ 10 6 | Tmin = 10 -7 s (= 100 ns) |