Safety, Health and Welfare at Work (General Application) Regulations 2007

F83 [ Schedule 11

Regulations 178 and 179

Artificial Optical Radiation ]

F83 [ Part 1

Non-Coherent Optical Radiation

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 these Regulations, the formulae above can be replaced by the following expressions and the use of discrete values as set out in the following tables:

Table 1.1: Exposure limit values for non-coherent optical radiation

Note 1: The range of 300 to 700 nm covers parts of UVB, all UVA and most of visible radiation; however, the associated hazard is commonly referred to as blue light hazard. Blue light strictly speaking covers only the range of approximately 400 to 490 nm.

Note 2: For steady fixation of very small sources with an angular subtense < 11 mrad, L B can be converted to E B . This normally applies only for ophthalmic instruments or a stabilised eye during anaesthesia. The maximum “ stare time ” is found by:t max = 100 / E B with E B expressed in W m -2 . Due to eye movements during normal visual tasks this does not exceed 100 s.

Table 1.2: S () [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	0.0120	228	0.1737	276	0.9434	324	0.000520	372	0.000086
181	0.0126	229	0.1819	277	0.9272	325	0.000500	373	0.000083
182	0.0132	230	0.1900	278	0.9112	326	0.000479	374	0.000080
183	0.0138	231	0.1995	279	0.8954	327	0.000459	375	0.000077
184	0.0144	232	0.2089	280	0.8800	328	0.000440	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	0.000410	378	0.000069
187	0.0166	235	0.2400	283	0.8122	331	0.000396	379	0.000066
188	0.0173	236	0.2510	284	0.7908	332	0.000383	380	0.000064
189	0.0181	237	0.2624	285	0.7700	333	0.000370	381	0.000062
190	0.0190	238	0.2744	286	0.7420	334	0.000355	382	0.000059
191	0.0199	239	0.2869	287	0.7151	335	0.000340	383	0.000057
192	0.0208	240	0.3000	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	0.6400	338	0.000303	386	0.000051
195	0.0239	243	0.3347	291	0.6186	339	0.000291	387	0.000049
196	0.0250	244	0.3471	292	0.5980	340	0.000280	388	0.000047
197	0.0262	245	0.3600	293	0.5780	341	0.000271	389	0.000046
198	0.0274	246	0.3730	294	0.5587	342	0.000263	390	0.000044
199	0.0287	247	0.3865	295	0.5400	343	0.000255	391	0.000042
200	0.0300	248	0.4005	296	0.4984	344	0.000248	392	0.000041
201	0.0334	249	0.4150	297	0.4600	345	0.000240	393	0.000039
202	0.0371	250	0.4300	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	0.3000	348	0.000215	396	0.000035
205	0.0510	253	0.4815	301	0.2210	349	0.000207	397	0.000033
206	0.0551	254	0.5000	302	0.1629	350	0.000200	398	0.000032
207	0.0595	255	0.5200	303	0.1200	351	0.000191	399	0.000031
208	0.0643	256	0.5437	304	0.0849	352	0.000183	400	0.000030
209	0.0694	257	0.5685	305	0.0600	353	0.000175
210	0.0750	258	0.5945	306	0.0454	354	0.000167
211	0.0786	259	0.6216	307	0.0344	355	0.000160
212	0.0824	260	0.6500	308	0.0260	356	0.000153
213	0.0864	261	0.6792	309	0.0197	357	0.000147
214	0.0906	262	0.7098	310	0.0150	358	0.000141
215	0.0950	263	0.7417	311	0.0111	359	0.000136
216	0.0995	264	0.7751	312	0.0081	360	0.000130
217	0.1043	265	0.8100	313	0.0060	361	0.000126
218	0.1093	266	0.8449	314	0.0042	362	0.000122
219	0.1145	267	0.8812	315	0.0030	363	0.000118
220	0.1200	268	0.9192	316	0.0024	364	0.000114
221	0.1257	269	0.9587	317	0.0020	365	0.000110
222	0.1316	270	1.0000	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	0.0010	368	0.000099
225	0.1500	273	0.9758	321	0.000819	369	0.000096
226	0.1583	274	0.9679	322	0.000670	370	0.000093
227	0.1658	275	0.9600	323	0.000540	371	0.000090

Table 1.3: B (), R () [dimensionless], 380 nm to 1400 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	10 ^{0.02 · (450- λ )}	1
600 < λ ≤ 700	0.001	1
700 < λ ≤ 1050	—	10 ^{0.002 · (700- λ )}
1050 < λ ≤ 1150	—	0.2
1150 < λ ≤ 1200	—	0.210 ^{0.02 · (1150- λ )}
1200 < λ ≤ 1400	—	0.02 ]

F84 [ Part 2

Laser Optical Radiation

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.

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:
dP	power expressed in watt [W];
dA	surface expressed in square metres [m2];
E ( t ), E	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;
H	radiant exposure : the time integral of the irradiance, expressed in joules per square metre [Jm ^-2];
t	time, duration of the exposure , expressed in seconds [s];
λ	wavelength , expressed in nanometres [nm];
γ	limiting cone angle of measurement field-of-view expressed in milliradians [mrad];
γ m	measurement field of view expressed in milliradians [mrad];
α	angular subtense of a source expressed in milliradians [mrad];
	limiting aperture : the circular area over which irradiance and radiant exposure are averaged;
G	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 [Jm ^-2 sr ^-1].

Table 2.1: Radiation hazards

Wavelength [nm] λ	Radiationrange	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 1400	IRA	eye	thermal damage	2.2, 2.3
700 to 1400	IRA	skin	thermal damage	2.4
1400 to 2600	IRB	eye	thermal damage	2.2
2600 to 10 ⁶	IRC	eye	thermal damage	2.2
1400 to 10 ⁶	IRB. IRC	eye	thermal damage	2.3
1400 to 10 ⁶	IRB. IRC	skin	thermal damage	2.4

Table 2.2 Exposure limit values for laser exposure to the eye Short exposure duration < 10 s

a If the wavelength of the laser is covered by two limits, then the more restrictive applies.

b When 1400 < 10 5 nm: aperture diameter = 1 mm for t 0.3 s and 1.5 t 0.375 mm for 0.3 s < t < 10 s; when 10 5 < 10 6 nm: aperture diameter = 11 mm.

c Due to lack of data at these pulse lengths, ICNIRP recommends the use of the 1 ns irradiance limits.

d The table states values for single laser pulses. In case of multiple laser pulses, then the laser pulse durations of pulses falling within an interval Tmin (listed in table 2.6) must be added up and the resulting time value must be filled in for t in the formula: 5.6 10 3 t 0.25

Table 2.3 Exposure limit values for laser exposure to the eye — Long exposure duration 10 s

a If the wavelength or another condition of the laser is covered by two limits, then the more restrictive applies.

b For small sources subtending an angle of 1.5 mrad or less, the visible dual limits E from 400 nm to 600 nm reduce to the thermal limits for 10 s ≤ t<T 1 and to photochemical limits for longer times. For T 1 and T 2 see Table 2.5. The photochemical retinal hazard limit may also be expressed as a time integrated radiance G = 10 ⁶ C B [J m ^-2 sr ^-1] for t > 10s up to t = 10000 s and L=100 C B [W m ^-2 sr ^-1] for t> 10000 s. For the measurement of G and L γ m must be used as averaging field of view. The official border between visible and infrared is 780 nm as defined by the CIE. The column with wavelength band names is only meant to provide better overview for the user. (The notation G is used by CEN; the notation L t is used by CIE; the notation L P is used by IEC and CENELEC.)

c For wavelength 1400 — 10 ⁵ nm: aperture diameter = 3.5 mm; for wavelength 10 ⁵— 10 ⁶ nm: aperture Diameter = 11 mm.

d For measurement of the exposure value the consideration of γ is defined as follows: If α (angular subtense of a source) > γ (limiting cone angle, indicated in brackets in the corresponding column) then the measurement field of view γ m should be the given value of γ . (If a larger measurement field of view is used, then the hazard would be overestimated). If α < γ then the measurement field of view γ m must be large enough to fully enclose the source but is otherwise not limited and may be larger than γ .

Table 2.4: Exposure limit values for laser exposure of skin

a If the wavelength or another condition of the laser is covered by two limits, then the more restrictive applies

Table 2.5: Applied correction factors and other calculation parameters

Table 2.6 Correction for repetitive exposure

Each of the following three general rules should be applied to all repetitive exposures as occur from repetitively pulsed or scanning laser systems:

1. 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.

2. 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.

3. The exposure from any single pulse within a group of pulses shall not exceed the singlepulse 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.

]

F85 [ Part 3

Assessment, Measurement and Calculation of Exposure

The methodology applied in assessment, measurement and/or calculations shall follow the standards of the International Electrotechnical Commission (IEC) in respect of laser radiation and the recommendations of the International Commission on Illumination (CIE) and the European Committee for Standardisation (CEN) in respect of non-coherent radiation.

In exposure situations which are not covered by these standards and recommendations, and until appropriate EU standards or recommendations become available, assessment, measurements and/or calculations shall be carried out using available international science-based guidelines. In both exposure situations, the assessment may take account of data provided by the manufacturers of the equipment when it is covered by relevant Community Directives. ]

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Safety, Health and Welfare at Work (General Application) Regulations 2007