Czech Metrology Institute  
Okružní 31, 638  00  Brno  
 
1.------IND- 2018 0589 CZ - EN- ------ 20181217 --- --- PROJET 
Executive summary for the EC (not part of this legislation)  
'Measuring instruments used to monitor activity limits and concentration of effluents from nuclear 
facilities, nuclear raw material mining or processing facilities, radioactive waste processing plants 
and from the processing or application of radioactive materials, and also used to determine 
environmental radiatio n exposure due to effluents – measuring instruments for continuous monitoring 
of radioactive gamma radioisotopes in liquid effluents from nuclear facilities ' – may be placed on the 
market and put into use in the Czech Republic as specified measuring instru ments  pursuant to 
Act No 505/1990 on metrology, as amended.  Pursuant to this act, the specified measuring instruments 
are measuring instruments in the List of Specified Measuring Device Types (Decree  No 345/2002) and 
specified (by the manufacturer/importer ) for measurement with relevance in the protection of the 
public interests in the following areas: consumer protection; contractual relations; stipulation of 
sanctions, fees, tariffs and duties; health protection; environmental protection; occupational saf ety or 
protection of other public interests protected by special legislation.  This therefore has a purpose 
similar to that used to identify stipulated products — non-automatic measuring and weighing 
instruments pursuant to Directives  2014/31/EU and 2014/32 /EU. The requirements of this legislation 
do not apply to measuring instruments not placed on the market in the Czech Republic for the above 
purposes, defined by Act  No 505/1990 on metrology.  
The purpose of this notified legislation is to lay down metrolog ical and technical requirements for the 
specified measuring instruments.  This legislation also stipulates tests for type approval and 
verification of specified measuring instruments of this type.  
(End of executive summary)  
 
Author:Mgr.Tomáš Hendrych  
Teleph one:+420 545 555 414  
 
 
P U B L I C  N O T I C E 
 
As the authority with substantive and territorial jurisdiction in the matter of laying down metrological 
and technical requirements for legally controlled measuring instruments and stipulating the testing 
methods for type approval and verification of legally controlled measuring instruments pursuant to 
§ 14(1) of Act  No 505/1990, on metrology, as amended (hereinafter the ‘Metrology Act’), and in 
accordance with the provisions of §  172 et seq. of Act  No 500/20 04, the Code of Administrative 
Procedure (hereinafter the ‘CAP’), the Czech Metrology Institute (hereinafter the ‘CMI’) commenced 
ex officio proceedings on 12  February  2016 pursuant to §  46 of the CAP, and, based on supporting 
documents, issues the followi ng: 
 
I. 
D R A F T   G E N E R A L M E A S U R E 
number:0111 -OOP -C075 -16 Measure of a General Nature No  0111 -OOP -C075 -16 
 
2 laying down the metrological and technical requirements for legally controlled measuring 
instruments, including testing methods for verification of the following legally controlled 
measuring instruments:  
 
‘measuring instruments used to monitor activity limits and concentration of effluents 
from nuclear facilities, nuclear raw material mining or processing facilities, 
radioactive waste processing plants and from the processing or application of 
radioactive materials, and also used to determine environmental radiation exposure 
due to effluents – measuring instruments for continuous monitoring of gamma 
radioisotopes in liquid effluents from nuclear facilities’  
 
1   Basic definitions  
For the purposes of this general measure, terms and definitions pursuant to VIM and VIML1 as well as 
the terms and definitions stated below will apply.  
1.1 
liquid effluent monitor  
a device for continuous monitoring of radioactive substances in liquid efflu ents from nuclear facilities  
1.2 
detection apparatus  
includes one or more radiation detectors and related functional units  
1.3 
control and evaluation apparatus  
comprises apparatus and functional units for measuring quantities related to ionising radiation 
(activity, activity concentration, etc.); the apparatus has functional units providing clear warnings that 
the measured quantity has exceeded a pre -set value  
1.4 
coefficient of variation  
the ratio V of the standard deviation s to the arithmetic mean x of a set of n measurements xi, given by 
the relationship:  


n
iix x
n x xsV
12) (
11 1
(1) 
1.5 
detection limit LD 
the measured value of a quantity obtained by a measurement procedure for which the probability of an 
untrue claim concerning the absence of a component in the material is β, where the probability of an 
untrue claim concerning its presence is α 
                                                      
1 TNI 01 0115 International Vocabulary of Metrology – Basic and General Concepts and Associated Terms 
(VIM) and International Vocabulary of Legal Metrology (VIML) are part of the technical harmonisation 
compendium ‘Terminology in the field of metrology’, which is publicly accessible at www.unmz.cz.  Measure of a General Nature No  0111 -OOP -C075 -16 
 
3 For a sample with a true content value of LD only 5  % of measurements will be erroneously declared 
as indistinguishable from the ambient environment (type  II error, β). The error β will equal error α 
(type  I error) in ambient measurement, when 5  % of ambient measurements exceed the measurement 
limit.Implicit values equal to 0.05 are recommended for α and β. 
The detection limit LD is determined as follows:  
LD = 1.645
)(2Bu (2) 
where  B  ............   is the ambient value;  
t   is the ambient measurement time;  
u(B)   is the ambient standard deviation.  
u(B) = 
tB  (3) 
1.6 
expansion factor  
a numerical coefficient ( k) used as a multiplier of the combined standard uncertainty in order to obtain 
an expanded uncertainty  
1.7 
decision variable  
a variable used to decide whether a given physical phenomenon is or is not present  
1.8 
decision level  
a fixed decision variable value that can be used to help decide if a given physical phenomenon is 
present if the result of the current measurement of the physical phenomenon has been exceeded  
1.9 
effective meter measuring range  
the range of values of the measured activity within which the propert ies of the part of the apparatus or 
system comply with specifications  
1.10 
dynamic range  
the ratio of the signal at the maximum measurable value of a quantity and the signal at the decision 
level  
1.11 
indication error  
the difference between the indicated value of a quantity  and this quantity's conventionally true value 
c at the measurement point  
 =  – c (4) 
1.12 
relative basic error  
the relative error of a reading ei of part of a device or a system with respect t o the given quantity under 
specified reference radiation and under specified reference conditions, expressed as:  Measure of a General Nature No  0111 -OOP -C075 -16 
 
4 
 
cc
ie(5) 
where:  the indicated value of the quantity;  
c   the quantity's conventional value at the measurement point.  
1.13 
response time  
the time needed after a step change in the measured quantity for the change in the output signal to first 
achieve a given relative value, usually 90  % of the final value  
1.14 
reference response  
under standard test conditions is given by the f ollowing relationship:  
crefAAR
(6) 
where: A ............   the value of the activity concentration indicated by the tested device or system;  
 Ac ........   the conventional value of the activity concentration.  
1.15 
sensitivity  
is the ratio of the value obtained through measurement and the conventional activity value  
AB-IS
(7) 
where:  I ...........   the indicated value from measurement of a radioactive sample;  
 B ..........   the indicated value from measurement without a radioactive sample;  
 A ..........   the conventional activity value of the measured sample.  
1.16 
activity concentration  
activity per unit volume of the measured liquid  
1.17 
units of measurement  
where appropriate, the following auxiliary units are used:  
 for time: year (r), day (d), hour (h),  minute (min .); 
 for energy: electron -volt (eV);  
 for activity concentration: Becquerel per cubic metre (Bq/m3) 
1.18 
kerma  
is defined as the sum of the initial kinetic energies of all the charged particles liberated by uncharged 
ionising radiation in a sample of matter, divided by the mass of the sample.  The unit is the gray (Gy).  
The kerma is used in the area of measurement of indirectly ionising radiation; it characterises energy 
transferred by indirectly ionising radiation (photons, neutrons) upon ini tial collision with charged 
particles (electrons, protons)  Measure of a General Nature No  0111 -OOP -C075 -16 
 
5 1.19 
kerma rate  
the kerma increase per time interval; the unit is Gy·s-1 
2   Metrological requirements  
2.1   Stipulated operating conditions  
A liquid monitor must comply with metrological requirements over the operating temperature and 
relative humidity range specified by the manufacturer.  
2.1.1    Reference conditions and standard test conditions  
The reference conditions and standard test conditions are listed in Table  1. 
Table 1 – Referenc e conditions and standard test conditions  
Influencing variables  Reference conditions  Standard test conditions  
Ambient temperature  20 °C 18 °C to 22  °C 
Relative humidity  65 % 50 % to 75 %  
Air pressure 1) 101.3  kPa 86 kPa to 106  kPa 
Power supply 2) nominal supply voltage VN VN ±1 % 
AC supply voltage frequency 2) nominal frequency  nominal frequency ±0.5  % 
AC supply voltage waveform 2) sinusoidal  sinusoidal with a total harmonic 
distortion of less than 5  % 
continued  
Table  1 – continued  
Influencing variables  Reference conditions  Standard test conditions  
Ambient gamma radiation  kerma rate in air 0.20 Gy/h  kerma rate in air <0.25 Gy/h  
Electrostatic field  negligible  negligible  
External electromagnetic field  negligible  less than the smallest value causing 
interference  
External magnetic field  negligible  less than twice the Earth's magnetic 
field value  
Control elements  configured for routine operation  configured for routine operation  
Radionuclide contamination  negligible  negligible  
Radon daughters  (222 and 220)  negligible  negligible  
Contamination by chemical 
products  negligible  negligible  
1) When the detection method is especially sensitive to air pressure changes, conditions are restricted to ±5  % of 
reference pressure.  
2) DC power can be used, in which case no frequency is specified.  Measure of a General Nature No  0111 -OOP -C075 -16 
 
6 2.2   Measuring range  
The monitor's measuring range is stipulated by the manufacturer.  
2.3   Instrument accuracy  
The manufacturer must stipulate the ratio between a reading on the measuring instrument and the 
activity of a reference source when the instrument is operating under standard test conditions and is 
configured according to the manufacturer's instructions.  The reference response uncertainty must be 
specified.  The reference response must not differ by m ore that 10  % of the value specified by the 
manufacturer.  
2.4   System linearity  
Under standard test conditions, the relative error of a reading must be less that ±10  % over the entire 
effective measurement range.  Uncertainty of sources of radiation is not  included.  When fixed sources 
are used, then  and c apply to sensitivity during relative error calculations (part  1.12).  
2.5   Response to other radionuclides  
The manufacturer must specify the response to appropriate radionuclides present in the liquid s ample.  
2.6   Response to ambient gamma radiation  
Because there is usually a relationship between the response to ambient gamma radiation and the 
decision level, and both parameters depend on the given operational use, the response to gamma 
radiation as wel l as the decision level must be agreed upon by the manufacturer and the user.  The 
manufacturer must stipulate the decision level and the maximum reading when a detector with 
protection from ambient gamma radiation is irradiated in the position specified by  the manufacturer 
with a step change in the kerma rate in air from the reference ambient air kerma rate to 10  Gy/h from 
137Cs. The response to irradiation with gamma radiation at any orientation and any gamma radiation 
energy up to 1.3  MeV (60Co) must not  exceed double the decision level value.  
2.7   Overload  
Unless agreed upon otherwise by the manufacturer and user, the device must indicate a reading past 
the upper end of the scale or indicate overload if it is irradiated by a source with activity concent ration 
10 times that of the upper limit of the measurement range, and once the source of overload is 
eliminated, must operate normally.  
2.8   Detection and evaluation device start -up time  
When irradiated with a source of radiation, the apparatus must indic ate a value that will not differ by 
more than ±10  % of the value obtained under standard conditions during the first 30  minutes after 
being switched on.  
2.9   Statistical fluctuations  
Given the statistical nature of radiation, read values may fluctuate aro und a central value.  The activity 
value coefficient of variation caused by statistical fluctuations must be less than 10  % for readings past 
the first decade of the effective measurement range.  
2.10   Stability of values indicated on detection and evaluati on device  
The value indicated for a given source of radiation after 30  minutes of operation must not change by 
more than 10  % over the subsequent 100  hours.  Measure of a General Nature No  0111 -OOP -C075 -16 
 
7 2.11   Flow rate stability  
The purpose of this test is to determine the nominal sampling flow rate or sampling stability under 
standard test conditions with a pressure drop caused only by the liquid circuit and retention apparatus.  
The manufacturer must specify a nominal flow rate for the type of retention apparatus used.  After the 
standard start -up per iod of the sampling apparatus (30  minutes) the indicated sampling flow rate value 
must not differ by more than ±10  % of the conventional flow rate value, and the sampling flow rate 
must not change by more than 10  % during the subsequent 100  hours.  
2.12   Influence of supply voltage on flow rate  
The flow rate must not change by more than 5  % when the supply voltage fluctuates between +10  % 
and –12 % of the nominal supply voltage.  
2.13   Influence of supply voltage frequency  
The flow rate must not change by m ore than 10  % when the supply voltage frequency changes from 
47 Hz to 51  Hz. 
2.14   Ambient temperature  
The indicated value must remain within the limits specified in Table  2 for the temperature range 
specified by the manufacturer.  It must be noted that for this type of apparatus, detection and sampling 
equipment may operate under different climactic conditions from the evaluation apparatus.  Part or all 
of the detection apparatus may operate at a higher temperature than specified in Table  2. 
Table  2 — Amb ient temperature  
Ambient temperature  Deviations under standard conditions  
+10 °C to +35  °C  
(midpoint:+22  °C) ±10 % 
–10 °C to +40  °C  
(midpoint:+15  °C) ±20 % 
−25 °C to +50  °C  
(midpoint:+12  °C) ±50 % 
2.15   Relative humidity  
Deviations caused by relative humidity up to 90  % at 35  °C must be less than 10  %. 
3   Technical requirements  
3.1   General requirements  
The main purpose of the apparatus for monitoring radioactive effluences is to provide information on 
whether effluents from all facilities c omply with stipulated effluent limits.  
This apparatus may also provide data on the proceedings of any processes being performed.  Even 
though this is usually a secondary purpose, under certain circumstances it is possible to anticipate 
situations where the detection of activities significantly below permitted levels can provide early 
warning of incorrect plant operation.  
Regardless of whether the purpose of effluent monitoring is to comply with requirements specified by 
a responsible authority or whether its  main purpose is to provide the user with monitoring information, 
the most frequent requirement is the ability to measure a defined effluent level characterised by 
activity concentration and overall effluent flow rate.  Measure of a General Nature No  0111 -OOP -C075 -16 
 
8 This ability is influenced by a numbe r of factors including detector type and characteristics, monitor 
operating mode, distribution of activity throughout the entire effluent flow, and sampling system 
efficiency (where only part and not all of the flow is measured).  
When taking into account v arious factors, it is evidently possible to optimise the detailed design of the 
monitor during the final phase of plant design, but in the beginning there is often insufficient data 
concerning monitoring requirements and how the entire system of effluents should be arranged in 
order to permit effective monitoring with the required degree of sensitivity.  For this reason, in order to 
achieve maximum efficacy , it is recommended that the required properties of the monitoring apparatus 
and the plant design be in fluenced already during the initial design phase of the plant in order to 
comply with monitoring requirements.  
3.2   Classification of liquid monitors  
Monitors can be classified according to their gamma radiation detection method as follows:  
 total gamma activity monitors;  
 gamma monitors discerning radionuclides emitting gamma radiation.  
Monitors can also be classified according to operating method:  
 with direct measurement using a detector placed in the effluent flow or in its vicinity;  
 continuous sampling  at the monitoring site, for example in a sampling chamber.  
3.3   Activity collection  
When it is impossible to directly measure effluent flow or take a representative sample due to low 
activity concentration of the effluent flow, various activity collectio n methods may be considered prior 
to measurement.  The most frequent such procedure is concentration of activity using a suitable 
sampling medium.  While this method is generally not possible for true continuous measurement, it can 
be used for quasi -continuous measurement, where activity is concentrated for a certain amount of time 
prior to measurement and where the concentration/measurement cycle repeats regularly.  In apparatus 
designed in this manner, collection must occur proportionally to th e overall volume of liquid released.  
3.4   Measurement and indication characteristics  
3.4.1    Effective measurement range  
The effective measurement range must be appropriate to the given application.  
3.4.2    Measurement characteristics  
The manufacturer mus t specify the decision level, detection limit and effective measurement range of 
the apparatus.  These characteristics must be provided for specified radionuclides, taking into account 
the reference ambient gamma radiation level (0.2  Gy/h) and activity con centrations in the liquid (of 
radon and its daughters).  
3.4.3    Display  
The indicated value should be the true activity concentration of the effluent.  This activity 
concentration is usually given in Bq/m3 for reference radionuclide 137Cs, or in the case of  monitors that 
can discern individual radionuclides, a set of radionuclides defined by the manufacturer.  
3.5   Reliability  
All apparatus must be designed to be as reliable as possible with a minimum of undetected faults.  Measure of a General Nature No  0111 -OOP -C075 -16 
 
9 The manufacturer must provide documentation concerning the expected MTBF of critical components 
such as air pumps, detectors, flow rate meters, etc.  
The manufacturer must specify the periodicity of regular maintenance and must fully describe all 
maintenance procedures.  Maintenance requ irements should be minimised.  
Warnings concerning faults must be available, indicating the system has a fault such as a power supply 
outage or a component failure.  
3.6   Sampling and detection apparatus  
3.6.1  Sampling and discharge pipes  
When designing sam pling apparatus, the following characteristics must be considered:  
 the internal diameter and length of pipes, the number and radius of bends;  
 the surface characteristics of internal pipe walls;  
 joins, prevention of particle trapping;  
 the properties of the structural material, minimisation of corrosion and erosion.  
If it is likely that the effluent contains suspended particles, the design should minimise particle 
trapping.  
3.6.2  Intake filter or retention apparatus  
If appropriate, a filter or other absorbent  medium may be situated in a holder at the intake of the 
sampling apparatus in order to eliminate certain substances.  A filter may simply be used to protect the 
activity monitor's measurement chamber from substances dissolved in the liquid, and in this cas e the 
operating personnel of the monitored building must be instructed that the measurement of this monitor 
is not representative of effluents from the given building.  Parts of the measuring system may be an 
apparatus intended for the separation of the mea surement of undissolved particles.  
3.6.3  Sampling chamber  
Where the sampling and detection apparatus includes a measurement chamber and where this chamber 
provides a volume of liquid for measurement using a submerged detector or a detector situated near 
the liquid, the following requirements apply:  
3.6.3.1    The sampling chamber must be a flow -through type, designed so that the volume of liquid 
flow-through remains constant.  
3.6.3.2    The volume of the sampling chamber and the pressure must be specified.  
3.6.3.3    The sampling chamber must be designed to minimise possible contamination.  Access to all 
elements of the sampling chamber during decontamination must be provided.  
3.6.4  Ionising radiation detector  
Any type of detector suitable for the required measurement according to the manufacturer's 
specifications may be used.  The manufacturer stipulates the detector type and all relevant parameters, 
especially the response at a defined geometry to the activity of measured radionuclides and other 
interfering  activities.  Regardless of the detector type used, the manufacturer will stipulate the response 
as a function of the gamma radiation energy, and if the detector is intended for spectroscopic 
measurement, also its resolution capacity as a function of energy . 
3.6.5    Ease of decontamination  
If possible, the detector must be protected from the measured liquid by a protective window of 
appropriate thickness.  Measure of a General Nature No  0111 -OOP -C075 -16 
 
10 If possible, it must be possible to quickly dismount the detector for repairs or replacement.  A defined 
detector position must be ensured so that the detector can always be mounted while preserving the 
required geometry.  The detection apparatus must be designed and built to minimise contamination and 
facilitate easy decontamination.  
3.6.6    Checking and cali bration  
The detection apparatus must be designed to easily situate the checking and calibration sources of 
radiation in a defined geometry near the detector.  
3.7   Alarms  
3.7.1    Alarm types  
Alarms and indication elements must be appropriate to the purpose  of the apparatus and must be 
specified by the manufacturer.  
High -level alarms and fault alarms must provide separate local visual indication on the monitor, and 
must also have two sets of output contacts (which may be common for all fault alarms) for exte rnal 
warning purposes.  Audible alarms may also be provided.  
All alarm functions must have means of testing alarm functionality.  In the case of a configurable 
alarm, it must be possible to perform a check within the configuration range with indication of th e 
current operating alarm point.  
Alarm circuits must operate in a mode where alarm conditions are maintained until they are 
specifically reset using a reset button, or in a mode where they automatically reset when the alarm 
state disappears.  
3.7.2    High -level alarms  
Configurable high -level alarms covering the entire effective measurement range must be provided.  
3.7.3    Fault alarms  
The following alarms must be provided:  
 indicating detector signal loss;  
 indicating loss of sampling in the circuit;  
 indicating  faults in the electronic system circuitry.  
Alarms must indicate the source of defects and must have an automatic diagnostic system.  
There must be a separate indication for each fault.  
3.8   Means of indication  
Aside from visual indication of the measured value, the apparatus must indicate that:  
 power is on;  
 the pump (if present) is on;  
 the high -voltage power supply for the detector (if present) is on;  
 the flow or level in the detector coolant tank (if present).  
If liquid flows through the apparatus, suitab le flow measurement indication must be provided.  
Outputs allowing remote indication of measurement and alarms must be provided.  Measure of a General Nature No  0111 -OOP -C075 -16 
 
11 3.9   Means for operating checks  
Means must be provided for the user to provide periodic checks to ensure satisfactory apparatus  
operation, including calibration and verification of measurement linearity.  These means must be 
installed in a manner that allows checks to be performed from the control and evaluation unit.  These 
checks must be performed using one or more (as needed) sui table sources of radiation.  
3.10   Means for configuration and maintenance  
All electronic devices must have a sufficient number of easily accessible test points to facilitate 
configuration and defect localisation.  All special maintenance tools and the appr opriate maintenance 
manual must be provided.  All apparatus must be designed to facilitate easy repair and maintenance.  
The display must provide information on automatic diagnostic elements.  
3.11   Ambient shielding or compensation apparatus  
This apparatus or procedures are used to reduce the influence of the ambient environment on 
measurement.  They involve the following types:  
 shielding apparatus;  
 electronic apparatus;  
 software methods.  
These types may be incorporated into the overall system design as needed.  
Shielding must provide identical radiation attenuation in all directions from the detector's sensitive 
volume, taking into account the structural materials used in the detection apparatus and the detector's 
angular response.  The shielding thickness  must be stipulated taking into account the detector's 
detection efficiency.  
If it is not possible to easily remove the apparatus from the shielding, the shielding must be easy to 
disassemble, and thus must comprise overlapping building -block elements.  
If electronic methods employing auxiliary detectors are used to reduce the influence of the ambient 
gamma radiation, these detectors must be selected and situated to achieve the best possible 
compensation, taking into account the gamma energy range and radiat ion direction.  
3.12   Apparatus noise levels  
Apparatus noise is primarily due to the sampling and detection apparatus, and especially from the 
operation of the pipe system and resultant vibrations.  
The manufacturer must select components and design the app aratus to minimise noise in line with the 
type of environment for which the apparatus is intended.  
3.13   Electromagnetic interference  
Measuring instruments must not be influenced by ambient electrical and electromagnetic interference, 
and must comply with  the requirements of relevant special legislation2). During the interference 
influence test, the change in the measuring instrument's response must not exceed 1  %. All necessary 
measures to minimise electromagnetic interference must be implemented, both th at received and 
emitted by the apparatus.  
Severity level  3 is used for resistance.  
                                                      
2) Government Regulation  No 117/2016 on product conformity assessment from the perspective of 
electromagnetic compatibility when being placed on the market.  Measure of a General Nature No  0111 -OOP -C075 -16 
 
12 Severity level  A is used for emission.  
3.14   Power  
The apparatus must be designed to operate on single -phase AC power in one of the following 
categories according to:  
 Serie s I:230  V AC; 
 series  II:100  V AC; 
 series  III:120  V or 240  V AC; 
 series  IV:24  V DC. 
The apparatus may be designed to operate on a low -voltage source of backup power in case of a power 
outage.  In these cases it is desirable that the apparatus does not malfunction due to the power supply 
switch or that no alarm is triggered, but this switch must be indicated.  
Air-fan motors may use three -phase power.  
3.15   Tamper protection  
The parts of the measuring instrument essential to its metrological properties m ust be designed to be 
secured in such a way as to provide proof of any unauthorised interference.  If the response of the 
measuring instrument can be adjusted to correct for long -term changes in response, correct for the 
effect of temperature and pressure o n response, or through application of a corrective factor, then the 
measuring instrument must be designed to rule out accidental changes to any factors configured by its 
operator.  Control switches and potentiometers must either be inside the measuring inst rument and 
inaccessible from the outside without using tools, or be clearly marked and fitted with a scale so that 
they can be precisely adjusted in accordance with the resolution capacity of the measuring instrument 
and then locked in order for the settin gs not to be changed accidentally.  Correction factors and 
calibration coefficients stored digitally must be impossible to change unless the operator enters a 
security code (or password) or changes the position of a blocked or inaccessible switch.  
3.16   Safety 
The measuring instrument must be safe in accordance with the basic principles of safety of ionising 
radiation installations and the requirements of relevant technical regulations under the conditions of 
normal use for the intended purposes.  
4   Measuring instrument markings  
4.1   Markings on the measuring instrument  
The following information must be provided on each part of the measuring instrument, which may 
consist of two functionally separate parts:  
a) Manufacturer identification;  
b) Designation  of the type of measuring instrument;  
c) the serial number of the measuring instrument's detector(s) and evaluation unit, pumps, flow 
meter;  
d) type-approval mark;  
e) ionising radiation meter safety information.  
All labels and inscriptions must be legible, durable,  unambiguous and impossible to remove using 
common means.  Measure of a General Nature No  0111 -OOP -C075 -16 
 
13 4.2   Official mark placement  
The placement of official marks on the detection part and the evaluation unit is specified in the type -
approval certificate.  
Where possible, marks are to be placed on t he front panel of the display unit so that they do not cover 
any of the information on the measuring instrument.  
5   Type approval of measuring instruments  
5.1   General  
The measuring instrument type -approval process includes the following tests:  
a) External inspection;  
b) instrument accuracy;  
c) system linearity;  
d) response to ambient gamma radiation;  
e) overload;  
f) detection and evaluation apparatus start -up time;  
g) statistical fluctuation;  
h) stability of values indicated on detection and evaluation apparatus;  
i) stability of f low rate or of the value of the quantity that characterises the concentration part of 
the cycle for measuring instruments operating in quasi -continuous concentration/measurement 
mode;  
j) influence of supply voltage on flow rate;  
k) influence of supply voltage fr equency;  
l) external leak;  
m) influence of ambient temperature;  
n) influence of relative humidity;  
o) electromagnetic compatibility.  
5.2   External inspection  
The external inspection assesses  
a) the completeness of the prescribed technical documentation, including the operating 
instructions;  
b) the conformity of the metrological and technical characteristics specified by the manufacturer in 
the documentation with the requirements of this regulation set out in Chapters  2 and 3;  
c) the completeness and status of the functional units of the measuring instrument according to the 
prescribed technical documentation;  
d) the software version of the measuring instrument with the version specified by the 
manufacturer.  
5.3   Functional tests  
5.3.1    Instrument accuracy  
The apparatus operate s under standard test conditions and is configured according to the 
manufacturer's instructions without the presence of reference radiation.  The ambient value is recorded.  
The apparatus is then irradiated with an appropriate reference source with sufficien t activity to provide Measure of a General Nature No  0111 -OOP -C075 -16 
 
14 values at approximately the midpoint of the scale or decade above the lowest scale or decade.  The 
indicated value is recorded and Rref is calculated.  
The measured value must not exceed the permitted change limits specified in Article  2.3. 
5.3.2    System linearity  
The test is performed using a set of sources with the same radionuclide and geometric characteristics.  
Standard preparation of test sources used in required tests must be such that the uncertainty in the 
absolute conventional activity value ( sa) of each source is better than 10  % (k = 2) and the relative 
conventional activity value ( sr) between sources of the given test set is better than 5  % (k = 2). Test 
sources must be linked to approved reference standards.  
Tests must be performed in one of two ways:  
 with liquid or solid sources of radiation;  
 through the application of an electrical signal.  
Type -approval tests are performed at one point on each scale for instruments with a linear scale, and 
on each decade of the effective measurement range for instruments with a digital or logarithmic 
display at approximately 25  % of the most sensitive range or decade, at 50  % of the maximum of 
central ranges or decades, and 75  % of the maximum value.  At least three of these tests must be 
performed using a radioactive source, with two being at limit values.  When electrical signals are used, 
they must be used for all ranges or decades (in addition to radionuclide sources).  
The measured value must not exceed the permitted change limits specifi ed in Article  2.4. 
5.3.3    Response to ambient gamma radiation  
Because there is usually a relationship between the response to ambient gamma radiation and the 
decision level, and both parameters depend on the given operational use, the response to gamma 
radiation as well as the decision level must be agreed upon by the manufacturer and the user.  The 
manufacturer must stipulate the decision level and the maximum reading when a detector with 
protection from ambient gamma radiation is irradiated in the positio n specified by the manufacturer 
with a step change in the kerma rate in air from the reference ambient air kerma rate to 10  Gy/h from 
137Cs. The response to irradiation with gamma radiation at any orientation and any gamma radiation 
energy up to 1.3  MeV (60Co) must not exceed double the decision level value.  
The apparatus must operate under standard test conditions without the presence of a radioactive 
source, and the indicated ambient value is determined.  The 137Cs is then situated relative to the 
detecto r so that the distance between the source and detector is at least 2  metres, and the conventional 
kerma rate in air at the detector location, if the detector was not present, would be 10  Gy/h  ± 10 %. 
The detector's reference orientation relative to the so urce must comply with the manufacturer's 
specifications.  Once irradiation has started, values are recorded at one -minute intervals until the values 
shown by the apparatus have reached a steady state.  Once a steady state has been achieved, at least 10 
readings are performed.  The decision level is calculated based on the last readings.  This decision level 
must comply with the manufacturer's specifications.  The maximum reading of the evaluation 
apparatus must not exceed the value specified by the manufact urer. The detector is then irradiated at 
several source -detector geometries according to the manufacturer's specifications.  If the evaluation 
apparatus can be programmed with a compensation factor for gamma radiation, this factor must not be 
changed during  the test.  Readings on the evaluation apparatus in all directions must not exceed double 
the value specified by the manufacturer for the reference direction.  
The above test is repeated for the reference source -detector direction using alternative sources o f 
gamma radiation as agreed upon by the manufacturer and user, including a 60 -Co source.  If the 
evaluation apparatus can be programmed with a compensation factor for gamma radiation, this factor 
must not be changed during the test.  Readings on the evaluati on apparatus must not exceed double the 
value specified by the manufacturer for 137Cs. Measure of a General Nature No  0111 -OOP -C075 -16 
 
15 The measured value must not exceed the permitted change limits specified in Article  2.6. 
5.3.4    Overload test  
The measuring instrument must indicate a value past the up per end of the scale, or indicate overload.  
If it is irradiated by a source with activity (or surface emission rate) up to ten  times the maximum of 
the measurement range, once the overload has ceased, it must function normally.  
a) The detection apparatus is e xposed to a source of radiation with activity that provides a reading 
at approximately 50  % of the first decade of the measurement range, and the reading is 
recorded.  
b) The detection apparatus is exposed to a source of radiation with activity ten  times the m aximum 
measurable value.  Irradiation is maintained for at least 10  minutes, and the instrument is 
checked to ensure that it permanently indicates a reading past the upper end of the scale.  
c) The source of radiation is removed and after a period of time agree d upon by the manufacturer 
and user, usually less than one hour, the detection apparatus is irradiated under the same 
conditions as in a).  The readings must not differ by more that 10  % of the original value.  
5.3.5    Detection and evaluation apparatus star t-up time  
When irradiated with a source of radiation, the apparatus must indicate a value that will not differ by 
more than ±10  % of the value obtained under standard conditions during the first 30  minutes after 
being switched on.  
Prior to this test, the a pparatus must be disconnected from power for at least one hour.  A source of 
radiation is used that provides a reading at approximately one  third to one  half of the range maximum.  
The detection and evaluation apparatus is switched on.  Readings are recorded every five minutes for 
one hour.  Ten hours after the apparatus was switched on, at least 10 readings are taken at appropriate 
intervals to obtain independent values.  The mean value is used as the 'final value' of readings.  A graph 
of the indicated activity  value over time is drawn, and if needed a correction is made for half -life. The 
difference between the 'final value' and the value read from the graph for 30  minutes must lie between 
specified limits.  
NOTE  When activity is very low, less than 10 times the  decision level, it may occur that during the start -up 
period the apparatus will not provide the required indicated value.  This is due to statistical deviations at low 
measured impulse frequencies.  
5.3.6    Statistical fluctuations  
Given the statistical nat ure of radiation, read values may fluctuate around a central value.  The activity 
value coefficient of variation caused by statistical fluctuations must be less than 10  % for readings past 
the first decade of the effective measurement range.  
A radioactive source that provides an indicated value between 10 and 20 times the decision level is 
used.  At least 10 readings are taken at appropriate intervals to obtain independent values.  The mean 
value and coefficient of variation are calculated from all readings.  The coefficient of variation must be 
within the required limits.  
The measured value must not exceed the permitted change limits specified in Article  2.9. 
5.3.7    Stability of values indicated on detection and evaluation apparatus  
The reading indicated for a given source of radiation after 30  minutes of operation must not change by 
more than 10  % over the subsequent 100  hours.  
A radioactive source that provides an indicated value between 10 and 20 times the decision level is 
used.  A sufficient number of read ings are performed after 30  minutes, then additional readings after 
10 hours and 100  hours without any changes to apparatus settings or conditions.  The mean reading 
values for all times must be between the specified limits.  
If needed, readings must be corr ected for half -life. Measure of a General Nature No  0111 -OOP -C075 -16 
 
16 The measured value must not exceed the permitted change limits specified in Article  2.10.  
5.3.8    Flow rate stability  
The purpose of this test is to determine the nominal sampling flow rate and sampling stability under 
standard test co nditions with a pressure drop caused only by the liquid circuit and an intake or 
sampling filter (clean filter).  The manufacturer must specify a nominal flow rate for the type of filter 
used.  After the standard start -up period of the sampling apparatus (30  minutes) the indicated sampling 
flow rate value must not differ by more than ±10  % of the conventional flow rate value, and the 
sampling flow rate must not change by more than 10  % during the subsequent 100  hours.  
This test is performed using distilled wa ter to prevent any changes to the pressure drop of the 
collection apparatus during the test.  For this test, a flow meter calibrated under measurement 
conditions with an uncertainty better than 3  % (k = 2) is installed at the intake of the liquid circuit.  The 
apparatus is turned on and flow rate is measured after 30  minutes, 5  hours, 20  hours and 100  hours of 
operation.Readings must comply with requirements.  
The measured value must not exceed the permitted change limits specified in Article  2.11.  
5.3.9    Influence of supply voltage on flow rate  
Supply voltage is varied between +10  % and –12 % of the nominal supply voltage.  
This test is performed using dustless air to prevent any changes to the pressure drop of the collection 
apparatus during the test.  For thi s reason, a HEPA filter with a very low pressure drop is placed in 
front of the air circuit.  For this test, a flow meter calibrated under measurement conditions with an 
uncertainty better than 3  % (k = 2) is installed at the intake of the air circuit.  The apparatus is turned on 
and flow rate is measured and recorded at stable voltage.  Then the supply voltage is varied over a 
defined range of 88  % Vn to 110  % Vn and the flow rate is simultaneously measured.  
The measured value must not exceed the permitted ch ange limits specified in Article  2.12.  
5.3.10    Influence of power frequency  
Power frequency is varied from 47  Hz to 51  Hz. 
During this test, the sampling and detection apparatus is connected to a power supply with nominal 
voltage and frequency that change s from 47  Hz to 51  Hz (alternative values are 57  Hz to 61  Hz). This 
test is performed using dustless air to prevent any changes to the pressure drop of the collection 
apparatus during the test.  For this reason, a HEPA filter with a very low pressure drop i s placed in 
front of the air circuit.  For this test, a flow meter calibrated under measurement conditions with an 
uncertainty better than 3  % (k = 2) is installed at th e intake of the air circuit. The flow rate is recorded 
at nominal frequency and at the s pecified frequency limits.  
The measured value must not exceed the permitted change limits specified in Article  2.13.  
5.3.11    External leak  
This test is used to determine the size of an external leak.  
The size of the leak is measured using two volume meters or flow rate meters; they must be mutually 
calibrated to an accuracy greater than 1  %. One meter is situated before the apparatus and the second 
in the direction of flow past the apparatus.  A series of 10 consecutive measurements is performed at 
suitable time intervals.  The mean values of flow rates measured before and after must not differ by 
more than 5  % during a normal sampling period.  
5.3.12    Ambient temperature  
It must be noted that for this type of apparatus, detection and sampling equipment may operate under 
different climactic conditions from the evaluation apparatus.  Part or all of the detection apparatus may 
operate at a higher temperature.  Measure of a General Nature No  0111 -OOP -C075 -16 
 
17 The detection apparatus is irradiated using a suitable test source in a manner that provides a known  
nominal reading value under standard test conditions.  This test is usually performed in a climate 
chamber.  It is usually not necessary to regulate humidity in the chamber if the apparatus is not 
especially sensitive to humidity changes.  Temperature is mai ntained at both limit values of the agreed  
upon temperature range for at least 24  hours.  During the last 30  minutes of this interval, the indicated 
value is read, which must be within appropriate limits.  The indicated value is also read at the midpoint 
of the temperature range shown in Table  2. If the reading at this median temperature is not within 
±10 % of the monitor's reading at the reference temperature, the manufacturer must specify the 
difference at this point.  
The measured value must not exceed the permitted change limits specified in Article  2.14.  
5.3.13    Relative humidity  
It must be noted that for this type of apparatus, detection and sampling equipment may operate under 
different climactic conditions from the evaluation apparatus.  Part or all of the detection apparatus may 
operate at a higher relative humidity.  
The detection apparatus is irradiated using a suitable test source in a manner that provides a known 
nominal reading value under standard test conditions.  The test may be performed at one t emperature, 
35 °C, and relative humidity of 90  %; the permitted reading deviation of ±10  % of the value is in 
addition to the permitted deviation caused by temperature alone.  
The measured value must not exceed the permitted change limits specified in Artic le 2.15.  
5.4   Electromagnetic compatibility tests  
Electromagnetic compatibility tests are performed with the monitor connected according to the 
manufacturer's specifications.  These tests must demonstrate that the monitor complies with the 
requirements of relevant special legislation2). 
5.4.1    Immunity to electrostatic discharge  
Immunity to electromagnetic discharge is tested with the apparatus switched on, using a contact 
discharge of 6  kV and an air discharge of 8  kV. Discharges are applied to conductive  surfaces and 
connecting plates.  
After this test, a subsequent apparatus accuracy test must not result in a measured deviation that 
exceeds limits specified in Article  2.3. 
5.4.2    Immunity to high -frequency electromagnetic fields  
Immunity to a radiated hi gh-frequency field is tested with the apparatus switched on, over a frequency 
range of 80  MHz to 3  000 MHz, with field intensity of 10  V/m.  Amplitude modulation 80  % 
AM/1  kHz sine.  
After this test, a subsequent apparatus accuracy test must not result in a measured deviation that 
exceeds limits specified in Article  2.3. 
5.4.3    Immunity to transients  
Immunity to repeated electrical transient disturbances is tested with the apparatus switched on.  A test 
voltage of ±0.5  kV, ±1  kV and ±2  kV is applied via a cou pling circuit to power, earth and signal 
inputs/outputs.  
After this test, a subsequent apparatus accuracy test must not result in a measured deviation that 
exceeds limits specified in Article  2.3. Measure of a General Nature No  0111 -OOP -C075 -16 
 
18 5.4.4    Immunity to surges  
Immunity to surges is tested by applying a test voltage of ±0.5  kV, ±1  kV and ±2  kV between power 
conductors.  
After this test, a subsequent apparatus accuracy test must not result in a measured deviation that 
exceeds limits specified in Article  2.3. 
5.4.5    Immunity to conducted disturba nces induced by radio -frequency fields  
Immunity to conducted disturbances induced by radio -frequency fields are tested with the apparatus 
switched on over a frequency range of 150  kHz to 80  MHz.  Amplitude modulation 80  % AM/1  kHz, 
voltage 10  V. 
After this test, a subsequent apparatus accuracy test must not result in a measured deviation that 
exceeds limits specified in Article  2.3. 
5.4.6    Immunity to interference due to a damped wave  
Immunity to interference due to a damped wave is tested with the apparatu s switched on, by applying 
damped waves to the monitor's power, signal and control inputs/outputs.  The test level is defined as 
the voltage of the first peak (maximum or minimum) of the test waveform, and is non -symmetrical 
2 kV, symmetrical 1  kV for a slo w damped 100  kHz and 1  MHz wave, and for a fast 3  MHz, 10  MHz 
or 30  MHz damped wave is 2  kV non -symmetrical.  
After this test, a subsequent apparatus accuracy test must not result in a measured deviation that 
exceeds limits specified in Article  2.3. 
5.4.7    Immunity to supply voltage dips, short interruptions and voltage variations  
Immunity to supply voltage dips, short interruptions and voltage variations is tested with the apparatus 
switched on, by applying a voltage dip to 0  % Vt for 10  ms. 
After this tes t, a subsequent apparatus accuracy test must not result in a measured deviation that 
exceeds limits specified in Article  2.3. 
5.4.8    Measurement of power line disturbances  
The tested monitor must comply with disturbance limits specified in Tables  3 and 4.  The test is 
performed with the apparatus switched on by measuring power line disturbances on the monitor's 
power, signal and control inputs/outputs.  If the reading on the measuring receiver fluctuates near 
limits, the reading must be monitored for at leas t 15 s at each measurement frequency.  The maximum 
value is recorded, except for random, brief extreme values, which are ignored.  
Table  3 contains voltage disturbance limits for power terminals.  
Table  3 — Limits for power line disturbances on power terminal s 
Frequency range  
(MHz)  dB limits (µV)  
Quasi -maximum  Median  
0.15 to 0.50  79 66 
0.50 to 30  73 60 
NOTE    Lower limits apply to band edge frequencies.  
Table  4 contains voltage disturbance limits for signal inputs/outputs.  Measure of a General Nature No  0111 -OOP -C075 -16 
 
19 Table  4 — Limits for power line disturbances on signal inputs/outputs  
Frequency range  
(MHz)  Voltage limits dB  (µV)  Current limits dB  (µA)  
Quasi -maximum  Median  Quasi -maximum  Median  
0.15 to 0.50  97 to 87  84 to 74  53 to 43  40 to 30  
0.50 to 30  87 74 43 30 
NOTE    Lower limits apply to band edge frequencies.  
5.4.9    Measurement of EM interference (radiated high -frequency interference)  
The tested monitor must comply with interference limits specified in Table  5.The test is performed 
with the apparatus switched on by measuring EM radiatio n at 10  metres.  If the reading on the 
measuring receiver fluctuates near limits, the reading must be monitored for at least 15  seconds at each 
measurement frequency.  The maximum value is recorded, except for random, brief extreme values, 
which are ignored.  
Table  5 — Radiated EM interference limits when measured at 10  m 
Frequency range  
(MHz)  Quasi -peak limits  
dB (µV/m)  
30 to 230  40 
230 to 1  000 47 
NOTE    Lower limits apply to band edge frequencies.  
6   Initial verification  
6.1   General  
During initial verification, the following tests are performed:  
a) a visual inspection;  
b) apparatus accuracy;  
c) system linearity;  
d) response to ambient gamma radiation;  
e) overload;  
f) statistical fluctuations;  
g) stability of values indicated on detection and evaluation apparatus;  
h) flow r ate stability;  
i) influence of ambient temperature.  
6.2   Visual inspection  
The inspection is performed in accordance with Article  5.2. 
6.3   Functional tests  
6.3.1    Apparatus accuracy test  
The test is performed in accordance with Article  5.3.1.  Measure of a General Nature No  0111 -OOP -C075 -16 
 
20 6.3.2    Apparatus linearity test  
The test is performed in accordance with Article  5.3.2.  
6.3.3    Test of response to ambient gamma radiation  
The test is performed in accordance with Article  5.3.3.  
6.3.4    Overload test  
The test is performed in accordance w ith Article  5.3.4.  
6.3.5    Statistical fluctuation test  
The test is performed in accordance with Article  5.3.6.  
6.3.6    Long -term stability test  
The test is performed in accordance with Article  5.3.7.  
6.3.7    Long -term flow rate stability test  
The test is performed in accordance with Article  5.3.8.  
6.3.8    Ambient temperature influence test  
The test is performed in accordance with Articles  5.3.12 and 5.3.13.  
7   Subsequent verification  
7.1   General  
During subsequent verification, the following tests are pe rformed:  
a) a visual inspection;  
b) apparatus accuracy;  
c) system linearity;  
d) overload;  
e) stability of values indicated on detection and evaluation apparatus.  
7.2   Visual inspection  
The inspection is performed in accordance with Article  5.2. 
7.3   Functional tests  
7.3.1    Apparatus accuracy test  
The test is performed in accordance with Article  5.3.1.  
7.3.2    Apparatus linearity test  
The test is performed in accordance with Article  5.3.2.  
7.3.3    Overload test  
The test is performed in accordance with Article  5.3.4.  Measure of a General Nature No  0111 -OOP -C075 -16 
 
21 7.3.4   Long -term stability test  
The test is performed in accordance with Article  5.3.7.  
8   Measuring instrument check  
When examining measuring instruments pursuant to §  11a of the Metrology Act at the request of a 
person who may be affected by an incorrect measurement, please proceed according to Chapter  7. The 
maximum permissible error used is double the maximum permissible errors pursuant to Chapter 7.  
9   Notified standards  
For the purposes of specifying the metrological and technical requiremen ts for measuring instruments 
and specifying the testing methods for their type approval and verification arising from this general 
measure, the CMI will notify Czech technical standards, other technical standards or technical 
documents of international or foreign organisations, or other technical documents containing more 
detailed technical requirements (hereinafter referred to as ‘notified standards’).  The CMI will publish a 
list of these notified standards attached to the relevant measures, together with the general measure, in 
a manner accessible to the public (on www.cmi.cz ). 
Compliance with notified standards or parts thereof is considered, to the extent and under the 
conditions stipulated by a general measure, to b e compliance with the requirements stipulated by this 
measure to which these standards or parts thereof apply.  
Compliance with notified standards is one way of demonstrating compliance with the requirements.  
These requirements may also be met by using anot her technical solution guaranteeing an equivalent or 
higher level of protection of legitimate interests.  
II. 
G R O U N D S 
The CMI issues, pursuant to §  14(1)(j) of the Metrology Act, toward the implementation of §  6(2), 
§ 9(1) and (9), and §  11a(3) of the  Metrology Act, this measure of a general nature, stipulating 
metrological and technical requirements for the specified measuring instruments and test methods for 
the type approval and verification of the specified measuring instruments — 'Measuring instru ments 
used to monitor activity and concentration of effluents from nuclear facilities, from nuclear raw 
material mining or processing facilities, from the processing or application of radioactive materials, 
and from radioactive waste processing plants, and  to determine environmental radiation exposure due 
to effluents — measuring instruments for continuous monitoring of radioactive gamma radioisotopes 
in liquid effluents from nuclear facilities'.  
Decree  No 345/2002 specifying measuring instruments for manda tory verification and measuring 
instruments subject to type approval, as amended, classifies the measuring instruments under item  8.1 
in the Annex entitled ‘List of specified measuring instruments’ as measuring instruments subject to 
type approval and mand atory verification.  
This legislation (Measure of a General Nature) was notified in accordance with 
Directive  (EU)  2015/1535 of the European Parliament and of the Council of 9  September  2015 laying 
down a procedure for the provision of information in the fi eld of technical regulations and of rules on 
Information Society services.  Measure of a General Nature No  0111 -OOP -C075 -16 
 
22 III. 
I N S T R U C T I O N S 
In accordance with §  172(l) APC, in conjunction with §  39(l) APC, the CMI has stipulated a time limit 
for comments of 30  days as of the date of posting the draft on the official notice board.  Comments 
submitted after this time limit will not be considered.  
The persons concerned are hereby invited to comment on this general draft measure.  With regard to 
the provisions of §  172(4) APC, comments are to be su bmitted in writing.  
Pursuant to the provisions of §  174(1) APC, in conju nction with the provisions of §  37(1) APC, it must 
be clearly stated who is submitting the comments, which general measure the comments concern, how 
the draft contradicts legislation o r how the general measure is inaccurate. The comments must also 
contain the signature of the person making the comments.  
The supporting documents for this draft general measure may be consulted at the Czech Metrology 
Institute, Legal Metrology Department, Okružní 31, 638 00 Brno, after making arrangements by 
telephone.  
This draft general measure shall be posted for 15  days.  
 
 
 
 
 
 
RNDr.Pavel Klenovský m.p.  
Director -General  
 
 
Person responsible for accuracy:Mgr.Tomáš Hendrych  
 
Posted on:17  October  2018  
Signature of the authorised person confirming posting:Tomáš Hendrych m.p.  
 
Removed on:  
Signature of the authorised person confirming removal: