EN 50496:2008
(Main)Determination of workers' exposure to electromagnetic fields and assessment of risk at a broadcast site
Determination of workers' exposure to electromagnetic fields and assessment of risk at a broadcast site
The object of this standard is to provide methods for assessing compliance with the requirements of the Directive 2004/40/EC [8] at a site operating one or more broadcast transmitters. This standard covers the frequency range up to 40 GHz. NOTE The Council and European Parliament Directive 2004/40/EC will be transposed into national legislation in all the EU member countries. It is recommended that users of this standard consult the national legislation related to this transposition in order to identify the national regulations and requirements. These national regulations and requirements may have additional requirements that are not covered by this standard.
Ermittlung der Exposition von Arbeitnehmern gegenüber elektromagnetischen Feldern und Bewertung des Risikos am Standort eines Rundfunksenders
Zweck dieser Europäischen Norm ist, Verfahren für die Beurteilung der Übereinstimmung mit den Anforderungen der Richtlinie 2004/40/EG [8] an Orten, wo ein oder mehrere Rundfunksender betrieben werden, bereitzustellen. Diese Europäische Norm deckt den Frequenzbereich bis 40 GHz ab. ANMERKUNG Die Richtlinie 2004/40/EG des Europäischen Parlaments und des Rates muss von allen Mitgliedstaaten der Europäischen Union in ihre nationale Gesetzgebung übernommen werden. Es wird empfohlen, dass Anwender dieser Norm die nationale Gesetzgebung in Bezug auf diese Umsetzung konsultieren, um die nationalen Rechtsvorschriften bzw. Regelungen und Anforderungen zu identifizieren. Diese nationalen Rechtsvorschriften bzw. Regelungen und Anforderungen können zusätzliche Anforderungen aufweisen, die durch diese Norm nicht abgedeckt werden.
Détermination de l'exposition des travailleurs aux champs électromagnétiques et évaluation des risques sur un site de radiodiffusion
L’objet de la présente norme est de fournir des méthodes pour évaluer la conformité d’un site exploitant un ou plusieurs émetteurs de radiodiffusion, aux exigences de la Directive 2004/40/CE [8]. La présente norme couvre la gamme de fréquences jusqu’à 40 GHz. NOTE La Directive du Conseil et du Parlement Européens 2004/40/CE sera transposée dans les législations nationales de tous les pays membres de l’UE. Il est recommandé aux utilisateurs de la présente norme de consulter la législation nationale liée à cette transposition afin d’identifier les règlementations et exigences nationales. Ces règlementations et exigences nationales peuvent avoir des exigences supplémentaires non couvertes par la présente norme.
Določevanje izpostavljenosti delavca elektromagnetnim sevanjem in ocena tveganja na mestu oddajnika
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN 50496:2009
01-marec-2009
'RORþHYDQMHL]SRVWDYOMHQRVWLGHODYFDHOHNWURPDJQHWQLPVHYDQMHPLQRFHQD
WYHJDQMDQDPHVWXRGGDMQLND
Determination of workers' exposure to electromagnetic fields and assessment of risk at a
broadcast site
Ermittlung der Exposition von Arbeitnehmern gegenüber elektromagnetischen Fieldern
und Bewertung des Risikos am Standort eines Rundfunksenders
Détermination de l'exposition des travailleurs aux champs électromagnétiques et
évaluation des risques sur un site de radiodiffusion
Ta slovenski standard je istoveten z: EN 50496:2008
ICS:
13.280 Varstvo pred sevanjem Radiation protection
SIST EN 50496:2009 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN 50496:2009
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SIST EN 50496:2009
EUROPEAN STANDARD
EN 50496
NORME EUROPÉENNE
November 2008
EUROPÄISCHE NORM
ICS 17.240
English version
Determination of workers' exposure to electromagnetic fields
and assessment of risk at a broadcast site
Détermination de l'exposition Ermittlung der Exposition
des travailleurs von Arbeitnehmern gegenüber
aux champs électromagnétiques elektromagnetischen Feldern
et évaluation des risques und Bewertung des Risikos
sur un site de radiodiffusion am Standort eines Rundfunksenders
This European Standard was approved by CENELEC on 2008-09-01. CENELEC members are bound to comply
with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard
the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 50496:2008 E
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Foreword
This European Standard was prepared by the Technical Committee CENELEC TC 106X,
Electromagnetic fields in the human environment.
The text of the draft was submitted to the formal vote and was approved by CENELEC as EN 50496
on 2008-09-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2009-09-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2011-09-01
__________
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Contents
1 Scope . 4
2 Normative references. 4
3 Terms and definitions . 5
4 Assessment methods . 6
4.1 Worker exposure assessment . 6
4.2 Use of public exposure assessment . 6
4.3 Assessment after technical modification . 7
5 Collection of technical data . 7
6 Determination of exposure levels by calculation or measurement . 7
6.1 Methodologies . 7
6.2 Additional considerations . 8
6.3 Determination process .10
7 Zoning of exposure work place .11
8 Checking of operating procedures in the different exposure work places.12
8.1 Work place access conditions .12
8.2 Signage and delimitation .12
8.3 Specific documentation .13
8.4 Personal protective equipment .13
8.5 Safety instructions .13
8.6 Maintenance work .13
8.7 Inspections .14
8.8 Active implantable medical devices .14
9 Information and training .14
9.1 Information for workers .14
9.2 Training of workers .15
10 Assessment report .15
Annex A (normative) Summation formulae .16
Annex B (informative) Marking .19
Bibliography .20
Figures
Figure 1 - Work place assessment process . 11
Figure B.1 - Presence of electromagnetic field sources . 19
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1 Scope
The object of this standard is to provide methods for assessing compliance with the requirements of
the Directive 2004/40/EC [8] at a site operating one or more broadcast transmitters.
This standard covers the frequency range up to 40 GHz.
NOTE The Council and European Parliament Directive 2004/40/EC will be transposed into national legislation in all the
EU member countries. It is recommended that users of this standard consult the national legislation related to this transposition
in order to identify the national regulations and requirements. These national regulations and requirements may have additional
requirements that are not covered by this standard.
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.
[1] EN 50413, Basic standard on measurement and calculation procedures for human exposure to
electric, magnetic and electromagnetic fields (0 Hz - 300 GHz)
[2] EN 50420, Basic standard for the evaluation of human exposure to electromagnetic fields from a
stand alone broadcast transmitter (30 MHz - 40 GHz)
[3] EN 50475, Basic standard for the calculation and the measurement of human exposure to
electromagnetic fields from broadcasting service transmitters in the HF bands (3 MHz - 30 MHz)
[4] EN 50499, Procedure for the assessment of the exposure of workers to electromagnetic fields
[5] EN 62226-2-1, Exposure to electric or magnetic fields in the low and intermediate frequency
range - Methods for calculating the current density and internal electric field induced in the human
body - Part 2-1: Exposure to magnetic fields - 2D models (IEC 62226-2-1)
[6] IEEE C95.3, Recommended Practice for Measurements and Computations of Radio Frequency
Electromagnetic Fields With Respect to Human Exposure to Such Fields
[7] Council Recommendation 1999/519/EC of 12 July 1999 on the limitation of exposure of the
general public to electromagnetic fields (0 Hz to 300 GHz) (Official Journal L 199 of 30 July 1999)
[8] Directive 2004/40/EC of the Parliament and of the Council on the minimum health and safety
requirements regarding the exposure of workers to the risks arising from physical agents
(Electromagnetic fields) – Official Journal of 30 April 2004
[9] International Commission on Non-Ionizing Radiation Protection, Guidelines for Limiting Exposure
to Time-Varying Electric, Magnetic, and Electromagnetic Fields (up to 300 GHz), Health Physics
Vol. 74, No 4, pp 494-522, 1998
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3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
action values
the magnitude of directly measurable parameters, provided in terms of electric field strength (E),
magnetic field strength (H), magnetic flux density (B), power density (S ), limb induced current (I )
eq L
and contact current (I ) at which one or more of the specified measures in [8] must be undertaken.
C
Compliance with these values will ensure compliance with the relevant exposure limit values of [8]
3.2
AIMD
Active Implantable Medical Device
3.3
antenna
device that serves as a transducer between a guided wave (e.g. coaxial cable) and a free space wave,
or vice versa
3.4
near-field region
region generally in proximity to an antenna or other radiating structure, in which the electric and
magnetic fields do not have a substantially plane-wave character, but vary considerably from point to
point. The near-field region is further subdivided into the reactive near-field region, which is closest to
the radiating structure and that contains most or nearly all of the stored energy, and the radiating near-
field region where the radiation field predominates over the reactive field, but lacks substantial plane-
wave character and is complicated in structure
3.5
broadcasting service
radiocommunication service in which the transmissions are intended for direct reception by the
general public. This service may include sound transmissions, television transmissions or other types
of transmission e.g. data
3.6
broadcast site
site operating one or more broadcast transmitters
3.7
contact current
current flowing into the body resulting from contact with a conductive object in an electromagnetic
field. This is the localised current flow into the body (usually the hand, for a light brushing contact).
Shocks and burns can be the adverse indirect effects. Contact current relates to a short term effect
and cannot be time-averaged
3.8
induced current
current flowing inside a human body resulting directly from an exposure to an electromagnetic field
3.9
employer
any natural or legal person who has an employment relationship with the worker and has responsibility
for the undertaking and/or establishment (Directive 89/391/EEC)
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3.10
exposure limit values
limits on exposure to electromagnetic fields in [8] which are based directly on established health
effects and biological considerations. Compliance with these limits will ensure that workers exposed to
electromagnetic fields are protected against all known adverse health effects of electromagnetic fields
3.11
local safety Instruction
safety instructions relating to a specific broadcast site and containing the information specified in
Clause 8:
– it must include all the necessary safety-related indications and, if applicable, point out the
possible risk of exposure to electromagnetic fields where these are at levels above the worker
action values;
– it could include all the necessary safety-related indications and, if applicable, point out the
possible risk of exposure to electromagnetic fields where these are at levels above the limits for
the general public
3.12
transmitter
device to generate the radio frequency broadcast signal which is fed into the antenna system
3.13
worker
any person employed by an employer, including trainees and apprentices but excluding domestic
servants (Directive 89/391/EEC)
3.14
work place
location where workers have access as part of their duties;
particular place of work within the broadcast site as for example the area near a transmitter with an
open enclosure, the area inside a transmitting antenna, on a ladder inside a broadcast mast / tower
and platforms under and above the antennas, the area around feed lines, etc.
4 Assessment methods
4.1 Worker exposure assessment
The assessment should be done using the steps outlined below:
– collection of technical data (Clause 5);
– determination of exposure levels by calculation or measurement (Clause 6). This includes
checking of operating procedures in the different exposure work places (Clause 8).
The results of the assessment process are:
– zoning of exposure work places (Clause 7);
– information and training (Clause 9);
– assessment report (Clause 10).
In the case of simultaneous exposure to multiple sources, the combined exposure shall be considered,
referring to Annex A.
4.2 Use of public exposure assessment
If an evaluation has already been undertaken in accordance with the provisions of Council
Recommendation 1999/519/EC [7], and the restrictions as specified therein are respected, then the
exposure limit values for workers of [8] are also met.
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4.3 Assessment after technical modification
After technical modification like maintenance or repair of the installation or the environment, it is
necessary to consider repeating or revising the assessment. This is particularly necessary if an
additional transmitter or antenna is added to a site where there are already one or more transmitters.
5 Collection of technical data
Information on the following items may be needed:
– with regard to the surrounding area
- information on the nature of the field from any external sources should be obtained from the
operators of those sources. Examples of useful information are the frequency, the type of
service, and whether the transmissions are intermittent. However, it should be noted that
much of the detailed information may be commercially sensitive.
– with regard to the site
- the area controlled e.g. information on property, fencing, where the controlled area is
bounded,
- the site map showing all facilities, e.g. buildings, towers, anchor cables, earth net…,
- the several areas
- where a public assessment has been done in compliance with [7] or national regulation,
- where workers have access without specific care,
- where workers have only access under specific circumstances.
– with regard to ELF emissions, the location of all 50 Hz site power supplies or transformers
connected to low voltage networks.
– with regard to the radio-frequency emissions, for each relevant source
- the mechanical configuration of the antennas, geometric dimensions, construction drawings,
position in the mast, etc.,
- radiation pattern, polarisation and gain of antennas,
- maximum and nominal power transmitter,
- frequency, type of modulation (AM, FM, COFDM, etc.), channel bandwidth,
- feeder type and length, attenuation/meter,
- additional losses (combiners, patch panels, antenna cables and power dividers).
- with regard to scheduling
- transmitting time table (especially for short wave),
- permitted operating configuration.
6 Determination of exposure levels by calculation or measurement
The collection of data permits to take into account the identification of sources of electromagnetic
fields in or around the site during the assessment. However, this standard does not directly address
product performance standards, which are intended to limit electromagnetic field (EMF) emissions
under specified test conditions.
6.1 Methodologies
The work place is often in near field conditions where the situation is rather more complicated than in
the far field. This is because the maxima and minima of the E and H fields do not occur together along
the direction of propagation as they do in the far field. In the near field, the electromagnetic field
structure may be highly inhomogeneous, and there may be substantial variations from the plane-wave
impedance of 377 ohms; that is, there may be preponderant E fields in some regions and
preponderant H fields in others. At 50 Hz, the E or the H- field may be very dominant, or both E and H
field may be present.
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As a consequence, for each type of electromagnetic source, it is not possible to specify specific
methodologies in this document. Therefore this standard refers to other appropriate standards to
define the appropriate methodologies [1].
6.1.1 Exposure from power supplies
The annex on AC electricity supplies in EN 50499 [4] gives guidance for assessing 50 Hz power
supplies and in particular criteria for power sources which are deemed to comply without any further
assessment.
6.1.2 Exposure from transmitters from 9 kHz to 100 kHz
Methodologies of measurement and calculation are defined in EN 62226-2-1 [5] and IEEE 95.1 [6].
6.1.3 Exposure from transmitters from 100 kHz to 30 MHz
Methodologies of measurement and calculation are defined in:
– EN 50475 [3] for 3 MHz to 30 MHz;
– between 100 kHz and 3 MHz: under consideration in CENELEC/TC 106X WG3.
Information can also be found in ITU-R BS.1698.
6.1.4 Exposure from transmitters from 30 MHz to 40 GHz
Methodologies of measurement and calculation are defined in EN 50420 [2].
Information can also be found in ITU-R BS.1698.
Subclause 6.3 gives the process for use of a broadband field meter in a mast. Assessment of both the
E and H fields may need to be performed.
6.2 Additional considerations
6.2.1 Use of action values
Compliance with the action values will ensure compliance with the relevant exposure limit values. If
the measured or calculated value exceeds the action values, it does not necessarily follow that the
exposure limit values will be exceeded.
6.2.2 Multiple exposure
With regard to simultaneous exposure to multiple frequency fields, it is important to identify multiple
sources of exposure or simultaneous exposure to multiple frequency fields and to use appropriate
methods of assessment, measurement and/or calculation capable of analysing the characteristics of
the waveforms and nature of biological interactions (see flowchart in Figure 1).
Once identified, the combination of different frequency components should be carried out separately
for thermal effects and electrical stimulation.
The formulae in Annex A apply to the relevant frequencies under practical exposure situations and
have to be used to establish compliance to the action levels or exposure limits for all the frequencies
together.
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6.2.3 Averaging
6.2.3.1 Time averaging
These following rules come from the ICNIRP Guidelines [9].
Exposure limit value
– For frequencies up to 10 GHz: all SAR values are to be averaged over any 6 min period.
– For frequencies between 10 GHz and 300 GHz: Power densities are to be averaged over any
2 1,05
20 cm of exposed area and any 68/f min period (where f is in GHz) to compensate for
progressively shorter penetration depth as the frequency increases.
Action value
– For frequencies between 100 kHz and 10 GHz: S , E², H², B² and I ² are to be averaged over any
eq L
6 min period.
Particular case: For E², H², S in case of specific modulation (like FM and digital OFDM
eq
emissions for instance), the field strength can be averaged over a lower period due to the
constant power transmitted, because average value is equal to the instantaneous value in this
case.
1,05
– For frequencies exceeding 10 GHz: S , E², H², and B² are to be averaged over any 68/f min
eq
period (f in GHz).
6.2.3.2 Spatial averaging
In case of whole body exposure, from basic physics, spatial averaging in the typical situation like in a
FM/TV mast, where a worker is moving in an EMF produced by a constant intensity source can b
...
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