EN ISO 20785-4:2021

SLOVENSKI STANDARD
01-oktober-2021
Dozimetrija za merjenje izpostavljenosti kozmičnemu sevanju v civilnem letalskem
prometu - 4. del: Kode za preverjanje veljavnosti (ISO 20785-4:2019)
Dosimetry for exposures to cosmic radiation in civilian aircraft - Part 4: Validation of
codes (ISO 20785-4:2019)
Dosimétrie pour l'exposition au rayonnement cosmique à bord d'un avion civil - Partie 4:
Validation des codes (ISO 20785-4:2019)
Ta slovenski standard je istoveten z: EN ISO 20785-4:2021
ICS:
13.280 Varstvo pred sevanjem Radiation protection
49.020 Letala in vesoljska vozila na Aircraft and space vehicles in
splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 20785-4
EUROPEAN STANDARD
NORME EUROPÉENNE
August 2021
EUROPÄISCHE NORM
ICS 13.280; 49.020
English Version
Dosimetry for exposures to cosmic radiation in civilian
aircraft - Part 4: Validation of codes (ISO 20785-4:2019)
Dosimétrie pour l'exposition au rayonnement (ISO 20785-4:2019)
cosmique à bord d'un avion civil - Partie 4: Validation
des codes (ISO 20785-4:2019)
This European Standard was approved by CEN on 25 July 2021.

CEN 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 CEN-CENELEC Management Centre or to any CEN
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 CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 20785-4:2021 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 20785-4:2019 has been prepared by Technical Committee ISO/TC 85 "Nuclear energy,
nuclear technologies, and radiological protection” of the International Organization for Standardization
(ISO) and has been taken over as EN ISO 20785-4:2021 by Technical Committee CEN/TC 430 “Nuclear
energy, nuclear technologies, and radiological protection” the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by February 2022, and conflicting national standards
shall be withdrawn at the latest by February 2022.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 20785-4:2019 has been approved by CEN as EN ISO 20785-4:2021 without any
modification.
INTERNATIONAL ISO
STANDARD 20785-4
First edition
2019-05
Dosimetry for exposures to cosmic
radiation in civilian aircraft —
Part 4:
Validation of codes
Dosimétrie pour les expositions au rayonnement cosmique à bord
d'un avion civil —
Partie 4: Validation des codes
Reference number
ISO 20785-4:2019(E)
©
ISO 2019
ISO 20785-4:2019(E)
© ISO 2019
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Published in Switzerland
ii © ISO 2019 – All rights reserved

ISO 20785-4:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 Quantities and units . 1
3.2 Atmospheric radiation field . 4
3.3 Software terms . 5
4 General considerations . 5
5 Functionality . 6
5.1 General . 6
5.2 Measured data . 6
5.3 ICRU reference data . 6
5.4 Code validation using measurements or reference data . 6
5.5 Considerations for the routine dose assessment . 6
Bibliography . 8
ISO 20785-4:2019(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 85, Nuclear energy, nuclear technologies,
and radiological protection, Subcommittee SC 2, Radiological protection.
A list of all the parts in the ISO 20785 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved

ISO 20785-4:2019(E)
Introduction
Aircraft crews are exposed to elevated levels of cosmic radiation of galactic and solar origin and
secondary radiation produced in the atmosphere, the aircraft structure and its contents. Following
recommendations of the International Commission on Radiological Protection (ICRP) in Publication
[1] [2]
60, the European Union (EU) introduced a Basic Safety Standards Directive (BSS) which included
exposure to natural sources of ionizing radiation, including cosmic radiation, as occupational exposure
[3]
for aircrew. International guidance was also provided by the IAEA Safety Standards Series . This
[4] [5] [6]
action was confirmed by ICRP Publications 103 and 132 , and the EU BSS was revised. The
Directive requires account to be taken of the exposure of aircraft crew liable to receive more than 1
mSv per year. It then identifies the following four protection measures:
i) to assess the exposure of the crew concerned;
ii) to take into account the assessed exposure when organising working schedules with a view to
reducing the doses of highly exposed crew;
iii) to inform workers concerned with the health risks involved in their work; and
iv) to apply the same special protection during pregnancy to female crew in respect of the ‘child to be
born’ as to other female workers.
The EU Council Directive has to be incorporated into laws and regulations of EU Member States and has
to be included in the aviation safety standards and procedures of the Joint Aviation Authorities and the
European Air Safety Agency. Other countries such as Canada and Japan have issued advisories to their
airline industries to manage aircraft crew exposure.
For regulatory and legislative purposes, the radiation protection quantities of interest are equivalent
dose (to the fetus) and effective dose. The cosmic radiation exposure of the body is essentially uniform
and the maternal abdomen provides no effective shielding to the fetus. As a result, the magnitude of
equivalent dose to the fetus can be put equal to that of the effective dose received by the mother. Doses
on board aircraft are generally predictable, and events comparable to unplanned exposure in other
radiological workplaces cannot normally occur (with the rare exceptions of extremely intense and
energetic solar particle events). Personal dosemeters for routine use are thus not needed nor practical,
The preferred approach for the assessment of doses of aircraft crew, where necessary, is to calculate
directly the effective dose rate, as a function of geographic location, altitude and solar cycle phase, and
to fold these values with flight and staff roster information to obtain estimates of effective doses
...