Annexes to COM(1998)268 - Limitation of exposure of the general public to electromagnetic fields 0 Hz-300 GHz - Main contents
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This page contains a limited version of this dossier in the EU Monitor.
| dossier | COM(1998)268 - Limitation of exposure of the general public to electromagnetic fields 0 Hz-300 GHz. |
|---|---|
| document | COM(1998)268  |
| date | July 12, 1999 |
DEFINITIONS
In the context of this recommendation, the term electromagnetic fields include static
fields, extremely low frequency (ELF) fields and radiofrequency (RF) fields, including
microwaves, encompassing the frequency range of 0 Hz to 300 GHz
A. Physical Quantities
In the context of EMF exposure, eight physical quantities are commonly used:
1. ('ontact current (/<•) between a person and an object is expressed in amperes (A). A conductive object in an electric field can be charged by the Held.
2 ('urrent density (J) is defined as the current [lowing through a unit cross section perpendicular to its direction in a volume conductor such as the human body or part of it, expressed in amperes per square metre (A/nr).
2. Idectrie field strength is a vector quantity (E) that corresponds to the force exerted on a charged particle regardless of its motion in space. It is expressed in volts per metre (V/m).
I Magnetic field strength is a vvclor quantity (31), which, together with the magnetic 1111x density, specifies a magnetic Held at any point in space. It is expressed in amperes pci metre (A/m).
5. Magnetic flux density is a vector quantity (B), resulting in a force that acts on moving charges, it is expressed in teslas (T). In free space and in biological materials, magnetic flux density and magnetic field strength can be interchanged using the equivalence 1 A m'1 ~ 4n l(f7 T.
(>. dower density (S) is the appropriate quantity used for very high frequencies, where the depth of penetration in the body is low. It is the radiant power incident perpendicular to a surface, divided by the area of the surface and is expressed in watts per square metre (VV/nf)
7 Specific energy absorption (SA) is defined as the energy absorbed per unit mass of biological tissue, expressed in joules per kilogram (J/kg). In these recommendations it is used for limiting lion-thermal effects from pulsed microwave radiation.
X Specific energy absorption rate (SAR) averaged over the whole body or over parts of'the body, is defined as the rate at which energy is absorbed per unit mass of the body tissue and is expressed in watts per kilogram (W/kg). Whole body SAR is a widely accepted measure for relating adverse thermal effects to RF exposure. Besides the whole body average SAR, local SAR values are necessary to evaluate and limit excessive energy deposition in small parts of the body resulting from special exposure conditions. Examples of such conditions are: a grounded individual exposed to RF in the low MHz range and individuals exposed in the near field of an antenna.
Of these quantities, magnetic flux density, contact current, electric and magnetic field strengths and power density can be measured directly.
B. Basic restrictions and reference levels
for the application of restrictions based on the assessment of possible health eflects of electromagnetic fields, differentiation should be made between basic restrictions and reference levels.
Rosie restrictions. Restrictions m exposure to time-varying electric, magnetic, and electromagnetic fields that at based directly on established health effects and biological considerations are termed “basic restrictions”. Depending upon the frequency of the field, the physical quantities used to specify these restrictions are magnetic flux density (15), current density (J), specitic energy absorption rate (SAR), and power density (S). Magnetic flux density and power density can be readily measured in exposed individuals.
Reference levels. These levels are provided tor practical exposure assessment purposes to determine if the basic restrictions are likely to he exceeded. Some lelerence levels are derived from relevant basic restrictions using measurements and/or computational techniques and some address perception and adverse indirect eflects of exposure to l ’MI's. The derived quantities are electric field strength (E), magnetic field strength (H), magnetic flux density («), power density (S), and limb current (//). Quantities, that address perception and other indirect eflects are (contact) current (A •) and, for pulsed fields, specific energy absorption (SA). In any particular exposure situation, measured or calculated values of any of these quantities can be compared with the appropriate reference level. Respect of the reference level will ensure respect of the relevant basic restriction. If the measured value exceeds the reference level, it does not necessarily follow that the basic icstriction will be exceeded. Under such circumstances, however, there is a need to establish whether there is respect of the basic restriction.
Quantitative restrictions on static electric ileitis are not given in these recommendations However, it is recommended that annoying perception of surface electric charges and spark discharges causing stress or annoyance should be avoided.
Some quantities such as the magnetic flux density (B) and the power density (S) serve both as basic restrictions and reference levels, at certain frequencies (see Annex II and
HD
ANNKX II
BASIC: RKSTRK TIONS
Depending on frequency, the following physical quantities (dosimetric / exposimctric quantities) are used to specify the basic restrictions on electromagnetic fields:
Between 0 and 1 Hz basic restrictions are provided for magnetic flux density for static magnetic fields (0 Hz) and current density for time varying fields up to 1 Hz, in order to prevent effects on the cardiovascular and central nervous system.
Between 1 Hz and 10 MHz basic restrictions are provided for current density to prevent effects on nervous system functions.
Between 100 kHz and 10 (ill/, basic restrictions on SAR are provided to prevent whole-body heat stress and excessive localised heating of tissues. In the range 100 kHz to 10 Ml I/, icstiictions on both cunenl density and SAR are provided.
Hot ween 10 (ill/ and (00 (ill/ basic lesliictions on power density aie provided to pi event heating, in tissue at or near the body suiface.
The basic restrictions, given in fable 1, are set so as to account for uncertainties related to individual sensitivities, environmental conditions, and for the fact that the age and health status of members of the public vary.
Table 1: Basic restrictions for electric, magnetic and electromagnetic fields (0 Hz -
300 GHz).
| Frequency range | Magnetic flux density (mT) | Current density (mA/m26 27 28 29 30 31 32 33 34) (rms) | Whole average (W/kg) | body SAR | Localised SAR (head and trunk) (W/kg) | Localised SAR (limbs) (W/kg) | Power density, S (W/m28) |
| 0 Hz | 40 | -- | -- | - | - | - | |
| >0-1 Hz | ~ | 8 | - | - | - | - | |
| MHz | - | 8/f | - | - | - | - | |
| 4 - 1000 Hz | - | 2 | -- | - | -- | - | |
| 1000 Hz -100 kHz | - | f/500 | - | - | - | - | |
| 100 kHz-10 MHz | -- | 17500 | 0.08 | 2 | 4 | - | |
| 10 MHz - 10 GHz | - | - | 0.08 | 2 | 4 | - | |
| 10 - 100GHz | __ | .... | 10 |
ANNEX III Reference Levels
Reference levels of exposure are provided lor the purpose of comparison with values of measured quantities. Respect of all recommended reference levels will ensure respect of basic restrictions.
If the quantities of measured values are greater than the reference levels , it does not necessarily follow that the basic restrictions have been exceeded. In this case, an assessment should be made as to whether exposure levels are below the basic restrictions.
The reference levels for limiting exposure are obtained from the basic restrictions for the condition of maximum coupling of the field to the exposed individual, thereby providing maximum protection. A summary of the reference levels is given in 'fables 2 and 3. The reference levels are generally intended to be spatially averaged values over the dimension of the body of the exposed individual, but with the important proviso that the localised basic restrictions on exposure are not exceeded.
In certain situations where the exposure is highly localised, such as with hand-held telephones and the human head, the use of reference levels is not appropriate. In such cases respect of the localised basic restriction should be assessed directly.
lucid levels
Table 2 Reference levels for electric, magnetic anil electromagnetic fields (0 II/. -
.100 (ill/, unperturbed mis values)
| Frequency range | E-field strength (V/m) | H-field strength (A/m) | B-field (pT) | Equivalent plane wave power density SCM (W/m2) ' |
| 0-1 Hz - | - | 3.2 x 104 | 4x 104 | - |
| l-X II/. | 10,000 | 3.2x104/f | 4x 104/f- | - |
| X 25 11/ | 10,000 | 4,000/f | .5,000/f | - |
| 0.025 -0.X kll/ | 250/f | 4/f | 5/f | - |
| 0.X 3 kll/. | 250/1' | 5 | 6.25 | - |
| 3 150 kllz | X7 | 5 | 6.25 | - |
| 0 15-1 Mil/ | X7 | 0.73/f | 0.02/f | - |
| 1-10 Mil/. | N7/f ' | 0.73/f | 0.02/f | - |
| 10 400 Mil/. | 3X | 0.073 | 0.002 | a |
| 400 - 2000 Mil/. | 1.375 f1 ' | 0.0037 f ' | 0.00 16 f ' | 17200 |
| 2 300 (ill/. | 61 | 0 In | 0.20 | 10 |
Moles: ■
1. / as indicated in the frequency range column.
2. For frequencies between 100 kHz and 10 GHz, „S'U1, E2, H\ and B2 are to averaged over any 6-minute period.
3. For frequencies exceeding 10 GHz, »Vcq, 1-2, H\ and B“ are to be averaged over any OS//1-minute period (/ in (ill/.).
•1 No E-lield value is provided for frequencies • I II/, which are effectively static elect lie fields For most people the annoying perception of surface electric charge.1: will not occur at field strengths less than 25 kV/m. Spark discharges causing stress or annoyance should be avoided.
l or peak values, the following icfcrcnce levels apply to the E-lield strength (V/m), II-lield strength (A/m) and the B-lield (pT):
For frequencies up to 100 kllz, peak reference values are obtained by multiplying the corresponding rms values by n/2 ( I d 14) For pulses of duration /,, the equivalent frequency to apply should be calculated as /- 1/(2/,).
For frequencies between 100 kHz and 10 MHz peak reference values are obtained by multiplying the corresponding rms values by ‘
10" , where a - (0.665 log(f/105)+0.176), fin kHz
- For frequencies between 10 MHz and 300 GHz peak reference values are obtained by multiplying the corresponding rms values by 32.
Although little information is available on the relation between biological effects and peak values of pulsed fields, it is suggested that, for frequencies exceeding 10 MHz, SCI| as averaged over the pulse width should not exceed 1000 times the reference levels or that field strengths should not exceed 32 times the fields strength reference levels. For frequencies between about 0.3 (il 1/ and several Gl 1/ and for localised exposure of the haul, in order to limit or avoid auditory elTects caused by thermoelaslic expansion, llie specific absorption from pulses must be limited. In this frequency range, the threshold SA of 4-16 mJ kg'35 for producing this effect corresponds, for 30-ps pulses, to peak SAR values of 130-520 VV kg'35 in the brain. Between 100 kHz and 10 MHz, peak values for the fields strengths are obtained by interpolation from the 1 5-fold peak at 100 kHz to the 32-fold peak at 10 Mllz.
('ontact currents and /imh currents
for frequencies up to 110 Mllz additional reference levels are recommended to avoid hazards due to contact currents. The contact current reference levels are presented in 'fable 3. The reference levels on contact current were set to account for the fact that the threshold contact currents that elicit biological responses in adult women and children are approximately two-thirds and one-half, respectively, of those for adult men
faille 3: Reference levels for contact currents from conductive objects
(fin klIz)
| f requency range | Maximum contact current (mA) |
| 0 Hz-2.5 kHz | 0.5 |
| 2.5 kHz - 100 kl Iz | o.2 f |
| 100 kl Iz - 110 Mllz | 20 |
ANNEX IV
Exposure from sources with multiple frequencies
In situations where simultaneous exposuie to liehls of dilVcrcnl frequencies occurs, the possibility that these exposures will be additive in their effects must be considered, ('aleulations based on such additivity should be performed separately for each ellect; thus separate evaluations should be made for thermal and electrical stimulation elVects on the body
Basic restrictions
In the ease of simultaneous exposure to fields of different frequencies, the following criteria should be satisfied in terms of the basic restrictions.
For electric stimulation, relevant for frequencies from I Hz up to 10 MHz, the induced current densities should be added according to:
where
J; is the current density at frequency i;
Ji.,; is the current density basic restriction at frequency i as given in Table I; SAKj is the SAR caused by exposure at frequency i;
SARi, is the SAR basic restriction given in Table I;
Si is the power density at frequency i,
S| is the power density basic restriction given in Table I.
Reference levels
lor application of I he basic restrictions, the following criteria regarding reference levels of field strengths should he applied.
I’oi induced current densities and electrical stimulation elfccts, relevant up to 10 Mil/., the following two requirements-should he applied to the field levels:
lMlh U)Mlh ^
y /" i y E> < /
inJ I * - -
/ l Hz l-l,i i IMIlz u
and where
i;, is the electric field strength at frequency i,
I’i , is the electric field strength reference level from Table 2;
11, is the magnetic field strength at frequency j;
I h , is the magnetic field strength reference level from 'fahle 2, a is X7 V/m and h is 5 A/m { (>.25 pT)
Compared to the ICNIKI* guidelines’ which deal with both occupational and general public exposure, cutoff points in the summations correspond to exposure conditions for members of the public.
The use of the constant values (a and b) above I Mil/ for the electric field and above ISO kHz for the magnetic field is due to the fact that the summation is based on induced current densities, and should not be mixed with thermal elTect circumstances, file latter forms the basis for IT , anil If. j above I MHz and 150 kHz respectively, found in Table 2.
1 International Commission on Non-ioni/.ing Radiation Protection. Guidelines for Limiting Exposure to Time-Varying'Electric.. Magnetic, and Electromagnetic Fields (up to 500 GHz). Health Phys., in press
I <»i ihcimal cffccl ciicumslaix cs, iclcvanl liom 100 kll/., t lu* following I wo icquiicmcnls .should In' applied to the lield levels
l.\ III:
10ih III;
/•;
i 100k U: C
E c-/' E <
and
f 50kllz .. 300GHz
Z * z <
lOOkll: G j -I30kllz
JLL
Ih-j
)~<l
./
whore .
I’, is the elect! ic lield strength at frequency i,
I i , is the elect! ic lield uTciencc level from Table 7,
11, is the magnetic lield sliem’lh al lre(|iiency j;
I li , is the magnetic lield refeience level derived liom Tables 2, c is S7/1'* ■’ V/m and d 0 7d/f A/m
Attain, compared to the I('NIKI* guidelines some cutolV points have been adjusted for public exposure only.
For limb current and contact current, respectively, the following requirements should be applied:
WUSIH: ( i Y
110 MHz I
•u
y <i
k-U)MII:
jLmU /
n-Ulz V,,i
where
h is the limb cunenl component al liequency k,
I, | is the releience level loi limb current, IS niA, l„ is the contact cm rent component al liequency n,
II Mis the refeience level for contact current at frequency n (see fable 3).
'flic above summation formulae assume worst-case phase conditions among the fields from the multiple sources. As a result, typical exposure situations may in practice result in less restrictive exposure levels than indicated by the above formulae for the reference levels.
3o
ISSN 0254-1475
COM(98) 268 final
DOCUMENTS
EN
05 15 12 14
Catalogue number : CB-CO-98-298-EN-C
ISBN 92-78-35921-1
Office for Official Publications of the European Communities L-2985 Luxembourg
1
United Nations Environment Programine/World Health Organization/Intemational Radiation Protection Association. Electromagnetic fields (300 Hz to 300 GHz). Geneva, World Health Organization; Environmental Health Criteria 137; 1993
2
European Commission, Non-ionizing radiation: Sources, exposure and health effects. Office for Official Publications of the European Communities, 1996, ISBN 92-827-5492-8
3
OJ N° C 205, 25.7.94, p. 439
4
COM (93) 559 final, 24.11.1993
5
OJ N° C 214, 16.7.1997, p. 7-10
6
OJN°L 156, 21.6.90, p. 14-18
7
OJ N° L 348, 28.11.92, p. 1-8
8
OJ N° C 77, 18.3.1993, p. 12-29
9
OJ N° C 230, 19.8.1994, p. 3-29
10
OJ N° L 077, 26.3.73, p. 29-33
11
" OJ N° L 139, 23.05.89, p. 19-26
12
OJ N° L 175, 5.7.85, p. 40-48
13
OJ N° L 73, 14.3.97, p. 5-15
14
COM (96) 511 final, and OJ N° C 129, 25.4.97, p. 14
15
,sOJN°L 126, 18.5.94, p. 1-33
16
COM(94) 145 final
17
The document “studyhr.doc” can be downloaded from the internet site http://www.ispo.cec.be/infosoc/telecompoliy/en
18
COM (97) 142 final, and OJ N° C 173, 7.6.97, p. 10
19
A similar system has been proposed for health and safety requirements for the protection of workers were a framework of threshold values and action values was presented.
20
OJ xxx
21
O.J. xxx
22
O.J. N° C 205, 25.7.94, p. 439
23
O.J. N°L 156,21.6.90, p. 14-18
24
O.J. N° L 348, 28.11.92, p. 1-8
25
O.J. N° C 77, 18.3.93, p. 12 and O.J. N° C 230, 19.8.94, p. 3-29
26
Notes
27
/is the frequency in Hz.
28
The basic restriction on the current density is intended to protect against acute exposure effects on central nervous system tissues in the head and trunk of the body and includes a safety factor .
29
Because of electrical inhomogeneity of the body, current densities should be averaged over a cross section of 1 cm28 perpendicular to the current direction.
30
For frequencies up to 100 kHz, peak current density values can be obtained by multiplying the rms value by V2 (-1.414). For pulses of duration tp the equivalent frequency to apply in the basic restrictions should be calculated as /= 1/(2/p).
31
5 For frequencies up to 100 kHz and for pulsed magnetic fields, the maximum current density associated with the pulses can be calculated from the rise/fall times and the maximum rate of change of magnetic flux density. The induced current density can then be compared with the appropriate basic restriction.
32
All SAR values are to be averaged over any 6-minute period.
33
Localized SAR averaging mass is any 10 g of contiguous tissue; the maximum SAR so obtained should be the value used for the estimation of exposure.
34
For pulses of duration tp the equivalent frequency to apply in the basic restrictions should be calculated as/= l/(2/p). Additionally, for pulsed exposures, in the frequency range 0.3 to 10 GHz and for localised exposure of the head, in order to limit and avoid auditory effects caused by thermoelastic expansion, an additional basic restriction is recommended. This is that the SA should not exceed 2mJ kg'1 averaged over 10 g of tissue.
35
oi the frequency range 10 Ml iz to I 10 Ml Iz, a reference level of 45 mA in terms of current through any limb is recommended. This is intended to limit the localised SAR over any 0-minule period