IEC 60846-2:2015

IEC 60846-2 ®
Edition 2.0 2015-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Radiation protection instrumentation – Ambient and/or directional dose
equivalent (rate) meters and/or monitors for beta, X and gamma radiation –
Part 2: High range beta and photon dose and dose rate portable instruments for
emergency radiation protection purposes

Instrumentation pour la radioprotection – Instruments pour la mesure et/ou la
surveillance de l’équivalent de dose (ou du débit d’équivalent de dose) ambiant
et/ou directionnel pour les rayonnements bêta, X et gamma –
Partie 2: Instruments portables de grande étendue, pour la mesure de la dose et
du débit de dose des rayonnements photoniques et bêta dans des situations
d’urgence de radioprotection
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IEC 60846-2 ®
Edition 2.0 2015-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Radiation protection instrumentation – Ambient and/or directional dose

equivalent (rate) meters and/or monitors for beta, X and gamma radiation –

Part 2: High range beta and photon dose and dose rate portable instruments for

emergency radiation protection purposes

Instrumentation pour la radioprotection – Instruments pour la mesure et/ou la

surveillance de l’équivalent de dose (ou du débit d’équivalent de dose) ambiant

et/ou directionnel pour les rayonnements bêta, X et gamma –

Partie 2: Instruments portables de grande étendue, pour la mesure de la dose et

du débit de dose des rayonnements photoniques et bêta dans des situations

d’urgence de radioprotection
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.280 ISBN 978-2-8322-3076-3

– 2 – IEC 60846-2:2015 © IEC 2015
CONTENTS
FOREWORD . 4
1 Scope and object . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Units and list of symbols . 7
5 General characteristics of ambient dose equivalent (rate) meters for emergency
purposes . 7
5.2 Read-out . 7
5.3 Dose equivalent and dose equivalent rate range . 7
5.5 Minimum range of measurement . 7
5.15 Portability . 7
5.16 Protection of switches . 8
5.17 Use of extension probe . 8
5.18 Contamination probe . 8
6 General test procedures . 8
7 Additivity of indicated value . 8
8 Radiation performance requirements and tests . 8
8.4 Variation of the response due to photon radiation energy and angle of
incidence . 8
 
8.4.3 Measuring quantity H'(0,07), H'(0,07), H*(10) or H*(10) for telescopic
or remote cylindrical probes . 8
8.5 Variation of the response due to beta radiation energy and angle of
incidence . 10

8.5.1 Measuring quantity H'(0,07) or H ′(0,07) . 10
8.7 Linearity and statistical fluctuations. 10
8.7.2 Requirements . 10
8.14 Extracameral response . 10
8.14.1 Requirements . 10
8.14.2 Method of test. 10
8.15 Response of instrument with extended probe . 10
8.15.1 Requirements . 10
8.15.2 Method of test. 11
9 Electrical characteristics of directional and ambient dose equivalent (rate) meters . 11
9.2 Warm-up time . 11
9.2.1 Requirements . 11
9.2.2 Test method . 11
9.2.3 Interpretation of the results . 11
10 Mechanical characteristics of directional and ambient dose equivalent (rate)
meters . 11
10.4 Drop test . 11
10.4.1 Requirements . 11
10.4.2 Method of test. 12
10.4.3 Interpretation of the results . 12
11 Environmental characteristics, performance requirements and tests . 12
11.2 Ambient temperature. 12
11.2.1 Requirements . 12

11.2.2 Test method . 12
11.2.3 Interpretation of the results . 13
11.3 Relative humidity . 13
11.3.1 Requirements . 13
11.8 Temperature shock . 13
11.8.1 Requirements . 13
11.8.2 Method of test. 13
11.8.3 Interpretation of the results . 14
12 Software . 14
13 Summary of characteristics . 14
14 Documentation . 14

Table 5 – Radiation characteristics of directional dose equivalent (rate) meters . 15
Table 6 – Radiation characteristics of ambient dose equivalent (rate) meters . 16
Table 7 – Electrical, mechanical and environmental characteristics of directional and
ambient dose equivalent (rate) meters . 17

– 4 – IEC 60846-2:2015 © IEC 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RADIATION PROTECTION INSTRUMENTATION –
AMBIENT AND/OR DIRECTIONAL DOSE EQUIVALENT (RATE)
METERS AND/OR MONITORS FOR BETA, X AND GAMMA RADIATION –

Part 2: High range beta and photon dose and dose rate portable
instruments for emergency radiation protection purposes

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60846-2 has been prepared by subcommittee 45B: Radiation
protection instrumentation, of IEC technical committee 45: Nuclear instrumentation.
This second edition cancels and replaces the first edition of IEC 60846-2, issued in 2007, as
well as IEC 61018, issued in 1991; it constitutes a technical revision.
The main technical change with regard to the previous edition consists of an update to the
revised edition of IEC 60846-1:2009.
This International Standard IEC 60846-2 is to be used in conjunction with IEC 60846-1:2009.
For the purposes of this standard, clauses/subclauses of IEC 60846-1:2009 apply, without
modifications, except when stated. The modified clauses/subclauses are identified by the
same number as in IEC 60846-1:2009 or, for new clauses/subclauses, by a higher number not
used in IEC 60846-1:2009.
The text of this standard is based on the following documents:
FDIS Report on voting
45B/822/FDIS 45B/834/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts of the IEC 60846 series, under the general title Radiation protection
instrumentation – Ambient and/or directional dose equivalent (rate) meters and/or monitors for
beta, X and gamma radiation, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 60846-2:2015 © IEC 2015
RADIATION PROTECTION INSTRUMENTATION –
AMBIENT AND/OR DIRECTIONAL DOSE EQUIVALENT (RATE)
METERS AND/OR MONITORS FOR BETA, X AND GAMMA RADIATION –

Part 2: High range beta and photon dose and dose rate portable
instruments for emergency radiation protection purposes

1 Scope and object
This part of IEC 60846 applies to portable or transportable dose equivalent (rate) meters
and/or monitors for the measurement of ambient and/or directional dose equivalent (rate) from
external beta, X and gamma radiation for energies up to 10 MeV during emergency situations.
The object of this International Standard is to specify the design requirements and the
performance characteristics of dose equivalent (rate) meters intended for the determination of
ambient and/or directional dose equivalent (rate) as defined in ICRU Report 47 under
emergency conditions. With the exception of modified or new clauses listed below, all clauses
in IEC 60846-1:2009 are applicable for instruments used for emergency purposes.
This International Standard does not specify which instruments are required nor does it
consider the numbers or specific locations of such instruments. This International Standard
does not identify instrumentation for specific types of accidents. It is essential that the rated
ranges of the instruments and the radiological and non-radiological conditions for which the
instruments are designed adequately cover the accident and post-accident conditions as
determined by accident analysis and/or specified by appropriate regulatory authorities or
qualified individuals. It is expected that accidents will involve both dose equivalent (rate) and
environmental extremes (e.g. temperature and humidity). Specifications for instruments for
measuring dose equivalent rates less than the minimum detectable dose rate level specified
in this International Standard are contained in IEC 60846-1:2009. Where such instruments are
also used for emergency measurements, the requirements of this International Standard
apply.
Although this International Standard specifies the requirements for instruments primarily for
emergency use, such instruments may also be used for on-site measurements at other times.
If the instrument has a remote detector and if an additional detector is provided in the
measuring assembly to measure dose equivalent rate at the location of the operator, the
requirements apply to both of the detectors.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
This clause of IEC 60846-1:2009 applies, with the following additional references:
IEC 60325:2002, Radiation protection instrumentation – Alpha, beta and alpha/beta (beta
energy > 60 keV) contamination meters and monitors
IEC 60846-1:2009, Radiation protection instrumentation – Ambient and/or directional dose
equivalent (rate) meters and/or monitors for beta, X and gamma radiation – Part 1: Portable
workplace and environmental meters and monitors

3 Terms and definitions
For the purposes of this document, the terms and definitions given in 3.1 to 3.33 of
IEC 60846-1:2009 and the following apply:
3.34
extracameral response
response to radiation of all the parts of the instrument except the detector itself
3.35
emergency situation
situation in which the dose equivalent (rates) of interest and one or more of the influence
quantities are not covered in IEC 60846-1
4 Units and list of symbols
For the purposes of this standard, the units and list of symbols given in 4.1 to 4.2 of
IEC 60846-1:2009 apply, without modifications.
5 General characteristics of ambient dose equivalent (rate) meters for
emergency purposes
For the purposes of this standard, 5.1 to 5.14 of IEC 60846-1:2009 apply, without
modifications, except as stated in the following subclauses. The changed subclauses are
identified by the same number as in IEC 60846-1:2009 or, for new subclauses, by a higher
number not used in IEC 60846-1:2009.
5.2 Read-out
Single scale is preferred. If multiple scales are used, the changing of measuring range and
read-out scale shall be simultaneous and shall be clearly displayed. All scales shall be
readable under normal lighting conditions.
5.3 Dose equivalent and dose equivalent rate range
The implementation of ICRP recommendations requires the determination of dose equivalent
rate over a wide range of values. Under some circumstances, dose equivalent rates as high
–1
require measurement. For application as an emergency instrument, the dose
as 10 Sv h
–1 –1
equivalent rates of interest are within the range from approximately 1 mSv h to 10 Sv h . If
integrating capability is provided, the range between 1 mSv to 10 Sv usually is of interest.
5.5 Minimum range of measurement
The minimum effective range of measurement of dose equivalent rate shall cover at least four
–1 –1
orders of magnitude and shall include the range from 1 mSv h to 10 Sv h . The minimum
effective range of dose equivalent shall cover at least four orders of magnitude and shall
include 10 Sv.
5.15 Portability
In the case of survey meters, the complete instrument should not exceed 4 kg in weight and
shall be equipped with handles, straps or other means to facilitate operation while being
carried. It is recognized that an extension probe or some other means may be required to
reduce the dose to the operator.

– 8 – IEC 60846-2:2015 © IEC 2015
5.16 Protection of switches
Switches and other controls shall be protected to prevent inadvertent de-activation or mal-
operation of the instrument.
5.17 Use of extension probe
If an extension probe is to be used, the instrument including the probe and all associated
equipment necessary for measurements including the extension device extended to the worst
case configuration shall be tested. Details of the test method shall be made available along
with the results.
5.18 Contamination probe
Emergency dose rate monitors are frequently provided with a surface contamination probe.
This probe shall meet the requirements of IEC 60325.
6 General test procedures
For the purposes of this standard, 6.1 to 6.14 of IEC 60846-1:2009 apply, without
modifications.
7 Additivity of indicated value
For the purposes of this standard, 7.1 to 7.3 of IEC 60846-1:2009 apply, without
modifications.
8 Radiation performance requirements and tests
For the purposes of this standard, 8.1 to 8.13 of IEC 60846-1:2009 apply, without
modifications, except as stated in the following subclauses. The changed subclauses are
identified by the same number as in IEC 60846-1:2009 or, for new subclauses, by a higher
number not used in IEC 60846-1:2009.
8.4 Variation of the response due to photon radiation energy and angle of incidence
 
8.4.3 Measuring quantity H'(0,07), (0,07), H*(10) or *(10) for telescopic or
H' H
remote cylindrical probes
8.4.3.1 General
Where telescopic or remote cylindrical probes with their calibration direction perpendicular to
the axis of symmetry are used for emergency instrumentation, this subclause 8.4.3 replaces
8.4.1 and 8.4.2 of IEC 60846-1:2009. In all other cases, subclauses 8.4.1 and 8.4.2 of
IEC 60846-1:2009 apply, without modification.
8.4.3.2 Requirements
The variation of the relative response due to a change of the photon radiation energy and
angle of photon radiation incidence shall not exceed the following values:
• –29 % to 67 % for photon radiation energies of 80 keV to 1,5 MeV and angle of photon
radiation incidence of 0° to ±60° and 180° to (180° ± 60°).
• –37,5 % to 150 % for photon radiation energies of 80 keV to 1,5 MeV and angle of photon
radiation incidence of ±60° to ±120°; however, at angle of photon radiation incidence of
90°±10° a lower response of –50 % is allowed.

• –37,5 % to 150 % for photon radiation energies of 1,5 MeV to 7 MeV and angle of photon
radiation incidence of 0° to ±60° and 180° to (180° ± 60°).
All indicated dose values shall be corrected for non-linear response and, if necessary, for the
effect of the influence quantity dose rate.
Where more than one detector is utilized, then these requirements shall apply to each
detector.
NOTE The range of the response –29 % to +67 % corresponds to the range of the correction factor 1,00 ± 0,40.
The range of the response –37,5 % to 150 % corresponds to the range of the correction factor 1,00 ± 0,60.
8.4.3.3 Method of test
The tests with X-rays should be performed using the narrow-spectrum series of radiation
qualities of ISO 4037-1, however if very high dose rates are required, the wide-spectrum
series or high air kerma rate series may be required.
In order to minimize the number of measurements, in a first step the minimum rated photon
energy is determined where both requirements on energy and angular dependence of
response are met:
• The energy dependence of response for angles of incidence of α = 0° normalized to its
value at Cs gamma energy, R(E , 0°), is measured and plotted versus the photon
i
energy at the points of the mean energies (fluence weighted) of the used X-ray spectra, E .
i
• The photon energy where the variation of the relative response falls outside –29 % to
+67 % (for 80 keV up to 1,5 MeV) or outside –37,5 % to +150 % (for 1,5 MeV up to 7 MeV)
is determined.
• For the radiation quality with the mean energy above the lower photon energy thus
determined, the relative response is measured for all angles between 0° and 180° at 15°
intervals in two perpendicular planes containing the reference direction through the
reference point of the dose equivalent (rate) meter.
– If for this radiation quality, all variations of the relative response are between –29 % to
+67 % (for 80 keV up to 1,5 MeV and 0° to ±60° and 180° to {180°±60°}) and between
–37,5 % to +150 % (for 80 keV up to 1,5 MeV and ±60° to ±120°; however at 90° the
variation of the relative response is allowed to be as low as –50 %) and between
–37,5 % to 150 % (for 1,5 MeV up to 7 MeV and 0° to ±60° and 180° to {180°±60°}, the
procedure shall be repeated with the radiation quality with the next lower mean photon
energy.
– Otherwise, the radiation quality with the higher mean energy shall be chosen.
For both radiation qualities used in the test, all measured responses are plotted as a function
of photon energy in a lin-log graph. Each two responses belonging together shall be
connected by a straight line. The minimum and maximum rated photon energy is obtained by
the intersection of the straight line with the specified limits at the highest photon energy.
In a second step, further radiation qualities in the rated range of use shall be chosen to prove
that all normalized responses R(E,α) are within its specified limits. One radiation quality is
determined by the maximum energy of the rated range of use. If the normalized responses
R(E , 0°) determined before have extreme values in the rated range, then the corresponding
i
radiation qualities are further values for these tests concerning the angle of incidence,
otherwise at least one quality shall be chosen within the rated range.
In principle, it is desirable that this test be performed at the same dose equivalent (rate) for
each radiation quality. In practice, this may not be possible, in which case, the indicated dose
equivalent (rate) for each radiation quality shall be corrected for the relative response at the
indicated dose equivalent (rate) (see 6.10 of IEC 60846-1:2009).

– 10 – IEC 60846-2:2015 © IEC 2015
8.4.3.4 Interpretation of the results
If all the variations of the relative response of the rated range of use due to photon radiation
energy and angle of incidence are within the limits given in 8.4.3.2, then the requirements can
be considered to be met.
8.5 Variation of the response due to beta radiation energy and angle of incidence

′
8.5.1 Measuring quantity H'(0,07) or H (0,07)
8.5.1.1 Requirements
The variation of the relative response of the directional dose equivalent (rate) meter to beta
90 90
Sr/ Y in the calibration direction, i.e., 0°
radiation produced by the reference radiation of
radiation incidence, shall be between –33 % to +100 %. In addition, the response to the
85 204
reference radiation of Kr or Tl shall be given by the manufacturer.
8.5.1.2 Method of test
90 90
For the beta radiation of Sr/ Y, the response shall only be measured for zero angle of
radiation incidence.
8.5.1.3 Interpretation of the results
If all the variations of the relative response of the rated range of use due to beta radiation
energy at 0° angle of incidence are within –33 % to +100 %, then the requirements can be
considered to be met.
8.7 Linearity and statistical fluctuations
8.7.2 Requirements
The requirements of IEC 60846-1:2009 apply, with the exception that Tables 5 and 6 of
IEC 60846-1:2009 are replaced by Tables 5 and 6 given in this standard.
8.14 Extracameral response
8.14.1 Requirements
The instrument shall not exhibit an extracameral response greater than or equal to 2 % of
–1
scale reading when exposed to a dose rate greater than or equal to 1 Sv h with photon
90 90
energy of 1,25 MeV and beta radiation from Sr/ Y.
8.14.2 Method of test
With the detector and its surrounding housing shielded or not in the radiation field, expose the
rest of the instrument, including cable, electronics (not contained in the housing in which the
–1
detector is contained), and the indicating device, to a dose rate of 1 Sv h with a photon
90 90
Sr/ Y (one after the other) for at least 10 min. The
energy of 1,25 MeV and betas from
scale reading (indicated value) shall be less than 2 % of the irradiated dose rate: that is less
–1
than 20 mSv h .
8.15 Response of instrument with extended probe
8.15.1 Requirements
The instrument with an extended probe shall exhibit no change in radiation characteristics
defined above when tested up to the maximum extension (or cable length) specified by the
manufacturer. Where multiple detectors are utilized to cover the entire range, they shall be
tested separately.
8.15.2 Method of test
The instrument shall be tested as required in 8.1 through 8.14 with the detector located at the
minimum and maximum distances (or cable length) specified by the manufacturer. The
response shall be the same, within 5 %, for both distances (or cable length).
9 Electrical characteristics of directional and ambient dose equivalent (rate)
meters
For the purposes of this standard, 9.1 to 9.3 of IEC 60846-1:2009 apply, without
modifications, except as stated in the following subclauses. The changed subclauses are
identified by the same number as in IEC 60846-1:2009 or, for new subclauses, by a higher
number not used in IEC 60846-1:2009.
9.2 Warm-up time
9.2.1 Requirements
The instrument shall be capable of starting operation at the lowest temperature of the rated
range and operate as normally. One (1) minute after instrument switched on, the indication
shall not differ by more than 10 % from the value obtained after 60 min.
9.2.2 Test method
The dose equivalent meter with the batteries fitted shall be placed for at least 4 h inside the
environmental chamber with the temperature at –25 °C. With the dose equivalent (rate) meter
switched off, expose it to an appropriate radiation source that will provide an indication in the
second most sensitive range. Switch on the instrument and note the readings every 15 s
during a period of 2 min after switching on.
60 min after switching on take a sufficient number of readings and use the mean value as the
final value of the indication.
9.2.3 Interpretation of the results
From the graph of readings as a function of time determine the reading after 1 min. If this
value does not differ by more than 10 % from the value obtained after 60 min then the
requirements of 9.2.1 are met.
10 Mechanical characteristics of directional and ambient dose equivalent (rate)
meters
For the purposes of this standard, 10.1 to 10.3 of IEC 60846-1:2009 apply, without
modifications, except as stated in the following subclauses. The changed subclauses are
identified by the same number as in IEC 60846-1:2009 or, for new subclauses, by a higher
number not used in IEC 60846-1:2009.
10.4 Drop test
10.4.1 Requirements
Portable dose equivalent (rate) meters used for emergency purposes shall be able to
withstand without damage, a drop from a height of 1 m (distance from ground point to surface
of dose equivalent (rate) meter) onto a concrete floor. The instrument passes the test if the
instrument response after the tests does not deviate from the original response by more than
–17 % to +25 %.
– 12 – IEC 60846-2:2015 © IEC 2015
10.4.2 Method of test
The dose equivalent (rate) meter shall be subjected to at least one single drop from 1 m to
each surface of dose equivalent (rate) meter. The test may be performed either with one or
more test units in such a way that one drop onto each surface of the dose equivalent (rate)
meter is tested. The response of the instrument shall be determined before and after the test.
If the dose equivalent recorded is important to measurement, then the data recorded before
drop shall be maintained and shall not be increased by more than 0,7 H (H is the lower limit
0 0
of the effective range of measurement). The drop can make the instrument switch off but the
user shall be able to switch the unit back on. The dose equivalent (rate) meter shall be
inspected and the physical condition be documented.
10.4.3 Interpretation of the results
If the instrument response does not deviate from the original response by more than –17 % to
+25 % and the instrument is in good physical condition then the requirements are met.
11 Environmental characteristics, performance requirements and tests
For the purposes of this standard, 11.1 to 11.7 of IEC 60846-1:2009 apply, without
modifications, except as stated in the following subclauses. The changed subclauses are
identified by the same number as in IEC 60846-1:2009 or, for new subclauses, by a higher
number not used in IEC 60846-1:2009.
11.2 Ambient temperature
11.2.1 Requirements
The indicated values of the portable dose equivalent (rate) meters used for emergency
purposes shall remain within the following ranges of the indicated values obtained at +20 °C
over the following temperature ranges:
a) Assemblies for extended temperature range: over the range of temperature from –25 °C to
+50 °C, the indicated value shall not deviate by more than –17 % to +25 % from that
obtained under standard test conditions. It is recommended that portable assemblies be
designed to meet these requirements for outdoor use.
b) Assemblies for extreme temperature range: where the assembly is to be used in hotter
conditions, the indicated value shall not deviate by more than –23 % to +43 % from that
obtained under standard test conditions over the temperature range of –25 °C to +70 °C.
c) Assemblies for all temperature ranges: where the assembly is to be used in hotter
conditions (e.g. fire), the indicated value shall not deviate by more than –23 % to +43 %
from that obtained under standard test conditions over the temperature range specified by
the manufacturer.
The manufacturer shall state the maximum temperature the instrument can withstand.
NOTE Some means of maintaining the batteries at a temperature within the nominal operation range may be
required when assemblies are operated at temperatures below –10 °C.
11.2.2 Test method
For this test, the dose (rate) meter shall be exposed to a photon radiation source of sufficient
intensity providing an indication in the second most sensitive range. The dose (rate) meter
and the photon source shall be arranged in a reproducible geometry for the test.
The dose (rate) meter shall be held at a temperature of +20 °C ± 2 °C and allowed to stabilize
for a minimum of 60 min. The indication of the dose (rate) meter shall be determined. The
dose (rate) meter and the source shall be removed from this environment and placed directly
in an environmental chamber such that the same exposure geometry is established and the

temperature near the meter is maintained within 5 °C for each maximum and minimum
temperature identified in the three temperature ranges given in 11.2.1. This procedure shall
be performed in less than 5 min. The temperature shall then be maintained at each of its
extreme values for at least 4 h, and the indication of the dose (rate) meter measured during
the last 30 min of the period. The dose (rate) meter shall be removed from the environmental
chamber and returned to the first environment such that the same exposure environment is
established and the temperature near the meter is +20 °C ±2 °C. This procedure shall be
performed in less than 5 min. The indication shall then be determined during the last 30 min
of a 2 h period.
It is not, in general, necessary to control the humidity of the air in the chamber unless the
meter is particularly sensitive to changes of humidity. Humidity levels should be low enough to
prevent condensation (<75 %).
11.2.3 Interpretation of the results
The requirements of IEC 60846-1:2009 apply.
11.3 Relative humidity
11.3.1 Requirements
The requirements of IEC 60846-1:2009 apply, with the exception that the minimal rated range
covers all relative humidity levels up to 95 % at a temperature of +35 °C.
11.8 Temperature shock
11.8.1 Requirements
The indicated value of the dose (rate) meter shall not vary by more than –17 % to +25 % from
the indicated value taken at a temperature of +20 °C when the temperature is raised from
+20 °C to +50 °C or lowered from +20 °C to –10 °C in less than 5 min.
The indicated value of the dose (rate) meter shall not vary by more than –17 % to +25 % from
the indicated value taken at a temperature of +50 °C or –10 °C when the temperature changes
from either one of the above temperatures to +20 °C.
11.8.2 Method of test
For this test, the dose (rate) meter shall be exposed to a photon radiation source of sufficient
intensity to provide an indication in the second most sensitive range. The dose (rate) meter
and the photon source shall be arranged in a reproducible geometry for the test.
The dose (rate) meter shall be held at a temperature of +20 °C ± 5 °C and allowed to stabilize
for a minimum of 60 min. The indication of the dose (rate) meter shall be determined. The
dose (rate) meter and the source shall be removed from this environment and placed directly
in an environmental chamber such that the same exposure geometry is established and the
temperature near the meter is maintained between +45 °C and +50 °C. This procedure shall
be performed in less than 5 min. The indication shall then be determined every 15 min over a
period of 2 h. The meter shall remain in this environment during the period to reach a stable
temperature.
The dose (rate) meter shall be removed from the environmental chamber and returned to the
first environment such that the same exposure environment is established and the
temperature near the meter is +20 °C ± 5 °C. This procedure shall be performed in less than
5 min. The indication shall then be determined every 15 min over a period of 2 h. The meter
shall remain in this environment during the period necessary to reach a stable temperature.

– 14 – IEC 608
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