EN 17694-2:2023

SLOVENSKI STANDARD
01-julij-2023
Hidrometrija - Minimalne zahteve za tehnične lastnosti in preskusni postopki za
opremo za nadzor vode - Naprave za ugotavljanje pretoka - 2. del: Instrumenti za
merjenje v zaprtem vodu
Hydrometry - Minimum performance requirements and test procedures for water
monitoring equipment - Devices for the determination of flow - Part 2: Closed conduit
instrumentation
Hydrometrie - Leistungsanforderungen und Prüfverfahren für
Wasserüberwachungsgeräte - Geräte zur Bestimmung des Durchflusses - Teil 2:
Messgeräte für geschlossene Rohrleitungen
Hydrométrie - Exigences minimales de performance et modes opératoires d'essai pour
les équipements de surveillance de l'eau - Dispositifs de mesure de l'écoulement - Partie
2 : Instruments de mesure pour écoulements en conduite fermée
Ta slovenski standard je istoveten z: EN 17694-2:2023
ICS:
07.060 Geologija. Meteorologija. Geology. Meteorology.
Hidrologija Hydrology
17.120.10 Pretok v zaprtih vodih Flow in closed conduits
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 17694-2
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2023
EUROPÄISCHE NORM
ICS 17.120.10
English Version
Hydrometry - Minimum performance requirements and
test procedures for water monitoring equipment - Devices
for the determination of flow - Part 2: Closed conduit
instrumentation
Hydrométrie - Exigences minimales de performance et Hydrometrie - Leistungsanforderungen und
modes opératoires d'essai pour les équipements de Prüfverfahren für Wasserüberwachungsgeräte - Geräte
surveillance de l'eau - Dispositifs de mesure de zur Bestimmung des Durchflusses - Teil 2: Messgeräte
l'écoulement - Partie 2 : Instruments de mesure pour für geschlossene Rohrleitungen
écoulements en conduite fermée
This European Standard was approved by CEN on 13 February 2023.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

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

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 17694-2:2023 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols . 8
5 Principle . 9
6 General requirements . 10
6.1 Requirements for closed conduit instrumentation . 10
6.2 Requirements for associated documentation . 11
7 Performance requirements . 12
7.1 Expression of performance requirements . 12
7.2 Performance requirements . 13
7.3 Data retention . 14
7.4 Environmental requirements . 14
7.5 Water temperature requirements . 14
7.6 Installation influences . 14
7.7 Field test requirements . 14
8 Testing . 15
8.1 General requirements for testing . 15
8.2 Laboratory test conditions . 15
8.3 Reporting . 17
9 Laboratory test procedures . 17
9.1 Guidance for establishing a test plan . 17
9.2 Verification by inspection . 20
9.3 Performance tests . 20
9.3.1 Loss of power for electronic CCIs . 20
9.3.2 Bias and repeatability . 20
9.3.3 Supply voltage . 21
9.3.4 Output impedance . 22
9.3.5 Water temperature . 22
9.3.6 Ambient air temperature and relative humidity . 22
9.3.7 Sensor location . 23
9.3.8 Presence of stray currents . 24
9.3.9 Bi-directional flow . 25
9.3.10 Flow reversal . 25
9.3.11 Ancillary devices . 25
9.3.12 Effect of conduit material . 26
9.3.13 Effect of conduit size . 26
9.3.14 Fill level. 27
9.3.15 Response time . 27
10 Field test procedures . 28
10.1 Objective of field test . 28
10.2 Field test plan . 28
10.3 Field test requirements . 28
10.4 Error under field test conditions . 29
10.5 Up-time . 29
10.6 Maintenance . 30
Annex A (normative) Evaluation of test data . 31
A.1 Introduction . 31
A.2 Bias. 31
A.3 Repeatability . 32
A.4 Effect of influence quantities . 32
A.5 Combined performance requirement . 32
A.6 Worked example . 34
A.6.1 Bias. 34
A.6.2 Repeatability . 35
A.6.3 Influence conditions . 35
A.7 Worked example — Field tests . 36
Annex B (informative)  Reference methods . 40
B.1 Laboratory methods . 40
B.2 Field (in situ) methods . 40
Annex C (informative) Reference uncertainty and error calculations . 41
Annex D (informative) Example report format . 43
Bibliography . 46

European foreword
This document (EN 17694-2:2023) has been prepared by Technical Committee CEN/TC 318
“Hydrometry”, the secretariat of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by November 2023, and conflicting national standards shall
be withdrawn at the latest by November 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This standard is published in two parts:
— EN 17694-1, Hydrometry — Minimum performance requirements and test procedures for water
monitoring equipment — Devices for the determination of flow — Part 1: Open channel
instrumentation
— EN 17694-2, Hydrometry — Minimum performance requirements and test procedures for water
monitoring equipment — Devices for the determination of flow — Part 2: Closed conduit
instrumentation
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
Introduction
This document is a product standard for instrumentation for the determination of the flow of waters in
closed conduits (e.g. effluent discharges from industrial installations, and wastewaters from sewage
treatment works, water irrigation channels and water transfer channels). A closed conduit instrument
(CCI) is a device that is normally fixed in position and used mainly to measure either volumetric flow-rate
and/or total volume passed. Certain CCI, e.g. Coriolis devices measure mass flow-rate and/or total mass
passed, from which volumetric flow may be derived, using the density of the water. This document
defines general requirements, minimum performance requirements, and test procedures. A CCI that is
shown, by means of the tests, to conform with the general requirements and performance requirements
is considered to be fit for purpose. However, this document does not cover the installation and on-going
use of a CCI, and also excludes instrumentation that is subject to separate legal control, for example, the
Measuring Instruments Directive.
The acronym “CCI” is used throughout this document except where it is necessary to be specific about the
particular type or component (e.g. sensor) of a device.
The general requirements and performance requirements specified in this document are intended to be
independent of measurement technology and applicable to all CCIs. The general requirements include
several features that are necessary to meet users’ applications and information that should be included
in associated documents.
The performance tests comprise testing carried out under laboratory and field conditions. They are
designed to determine, in a systematic and consistent way, the capability of CCI to make reliable
measurements. The testing focuses on key performance characteristics. Statistical procedures are defined
for evaluation of the test data.
Measurement ranges are not specified as part of the performance requirements though a minimum ratio
(maximum measured value: minimum measured value) is specified. It is for the manufacturer of the CCI
to decide on the measurement range over which the performance requirements are shown to be met by
the specified test procedures. Similarly, it is for the CCI manufacturer to decide on the intended uses
(applications) which will inform the design of the field trial.
Water monitoring equipment is widely used for compliance monitoring purposes under national and
European regulations.
1 Scope
This document specifies general requirements, minimum performance requirements and test procedures
for instrumentation used to measure either volumetric flow-rate and/or total volume passed of water in
closed conduits. It covers all closed conduit instrument (CCI) technologies intended to operate in closed
pressurized pipes and partially filled pipes. Requirements are expressed in volumetric units which may
be converted to mass using the density of the water.
It is recognized that for some CCIs certain tests cannot be carried out.
The data obtained from the testing of CCIs in accordance with the requirements of the Measuring
Instruments Directive [1] or EN ISO 4064-1 [2] can be used to meet, in part, the requirements specified
in this document. However, for the avoidance of doubt, compliance with the requirements of this
document does not equate to compliance with the requirements of the Measuring Instruments Directive
or EN ISO 4064-1.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
combined performance requirement
combination of individual performance requirements
3.2
conduit
pipe through which water is flowing
3.3
closed conduit instrument
CCI
device(s) which measures the flow-rate or totalized volume of water passing along a conduit or computes
such quantities from measurements of one or more properties which have a defined relationship with
the flow-rate
Note 1 to entry: A closed conduit instrument can, for example, include a complete flow-metering system, such as: a
flow sensor and transmitter, a mechanical CCI including any ancillary device required to derive an electronic output,
a velocity-area CCI comprising a water velocity sensor with a water level sensor and associated electronics, or a
non-standardized primary device with a differential pressure sensor and associated electronics.
3.4
determinand
property that is required to be measured
3.5
expanded uncertainty
expanded measurement uncertainty
U
product of a combined measurement uncertainty and a factor larger than the number one
Note 1 to entry: The factor depends upon the type of probability distribution of the output quantity in a
measurement model and on the selected coverage probability.
Note 2 to entry: The term “factor” in this definition refers to a coverage factor.
Note 3 to entry: Expanded measurement uncertainty is termed “overall uncertainty” in paragraph 5 of
Recommendation INC-1 (1980) (see the GUM) and simply “uncertainty” in IEC documents.
[ISO/IEC Guide 99:2007, 2.35 plus notes] [3]
3.6
flow-rate
q
volume of water passing through the CCI per unit time
3.7
influence quantity
quantity, generally external to the CCI, which may affect the performance of the equipment
3.8
insertion sensor
sensor designed to be inserted into a pipe through a tapping or other fitting, or mounted internally within
a pipe, in direct contact with the water and connected to a transmitter mounted externally to the pipe
3.9
measurement range
range over which the CCI conforms within the performance requirements specified in this document
Note to 1 entry: The measurement range is defined from a minimum non-zero value to a maximum value.
3.10
non-invasive sensor
sensor for application to a pipe which attaches to the outside of a pipe and requires no tapping, drilling
or cutting of the pipe to install, for example clamp-on ultrasonic transducers
3.11
percentage error
error in measurement expressed as a percentage of the true or actual value
Note 1 to entry: In this document, the true or actual value is the reference value and percentage error is calculated
using the following equation: percentage error = 100 × (measured value – reference value)/reference value.
3.12
performance requirement
one of the quantities (described by values, tolerances, range) that defines a CCI’s performance
3.13
rated operating conditions
minimum to maximum values of any environmental, fluid or electrical parameter within which a CCI is
designed to operate without adjustment, within the performance requirements specified in this
document
3.14
reference conditions
specified set of values (including tolerances) of influence variables, delivering representative values of
performance requirements
3.15
reference method
method to be used to obtain the determinand value to a stated uncertainty, against which the readings
from the CCI under test can be compared
3.16
repeatability
ability of a CCI to provide closely similar indications for repeated applications of the same determinand
under the same conditions of measurement
3.17
sensor
transducer consisting of one or more components from which is derived an electrical or mechanical
output related to a property from which the flow-rate may be computed
3.18
totalized volume
total volume of water which has been measured by the CCI over a period of time which commenced when
the totalizer was set to zero
4 Symbols
For the purposes of this document the following symbols apply.
b bias
S repeatability
R
X errors due to variations in supply voltage
V
X errors due to variations in output impedance
O
X errors due to variations in water temperature
FT
errors due to variations in ambient air temperature
X
T
X errors due to variations in relative humidity
RH
X errors due to variations in sensor location
SL
X errors due to variations in stray currents
SC
U combined performance requirement
C
5 Principle
This document sets general requirements, minimum performance requirements and test procedures for
a CCI that is to be used for determining the flow of water in closed conduits.
The general requirements are based on experience of users’ needs when operating a CCI in a range of
applications. Many are consistent with general requirements specified in EN ISO 4064-1.
The minimum performance requirements specify limit values in terms of percentage error for
measurement bias, repeatability, a range of environmental and sensor operational parameters, and for a
combination of all of these values. A CCI that can be demonstrated by the specified tests to conform with
the performance requirements is judged to be fit for purpose.
For the majority of applications where a CCI is used, the required parameter is volumetric flow-rate.
In Table 2 the combined performance requirement is less than the sum of the specified individual
performance values combined in quadrature. This allows for some differences in the performance of a
CCI with respect to the individual requirements within an overall combined performance requirement.
The laboratory performance tests are designed to show whether a CCI can conform with the applicable
performance requirements under a range of environmental and sensor operational conditions.
Laboratory testing is used to determine the performance characteristics in a systematic and consistent
way in a controlled environment. Several of the laboratory tests correspond to tests specified in
EN ISO 4064-2 [4] and ISO 12242 [5]. For CCI that are tested to demonstrate conformity with
EN ISO 4064-1 and ISO 12242 the test data can also be used for the purposes of this document thereby
minimizing the amount of testing.
Statistical procedures are defined for evaluation of the laboratory test data to produce the individual
performance characteristic measurement uncertainties, u, and the combined performance characteristic
measurement uncertainty, U . They are based on the ISO/IEC Guide 98-3 [6]. The measured errors arising
C
from the tests for each performance tests are converted to standard uncertainties, taking into account
the distribution of errors. To obtain the combined performance characteristic, the individual
uncertainties are combined using a root sum of squares, as described in the GUM, with due account taken
of the contribution of each component through the use of sensitivity coefficients. To determine sensitivity
coefficients, it is necessary to know the functions by which each component contributes to overall error.
In the case of CCI testing this will rarely be known. Hence, for the purposes of this document, the
sensitivity coefficients are all taken as 1.
The combined performance characteristic, U , is expressed as an expanded uncertainty. The expanded
C
uncertainty, (U), is obtained by multiplying the standard uncertainty by a coverage factor. The coverage
factor is determined by the confidence level. This document uses a 95 % confidence with a coverage
factor assumed to be 2.
The field trial is used to demonstrate that the performance of a CCI can be maintained under operational
conditions and to determine the CCI’s up-time.
6 General requirements
6.1 Requirements for closed conduit instrumentation
A CCI shall have:
a) a unique designation that unambiguously identifies the CCI (e.g. model, serial number);
b) a means of protection against inadvertent or unauthorized access to the control functions (e.g.
password, physical locks, etc);
c) an output signal and/or display scaled in metric units (the units of measurement shall be displayed
on the indicating device);
d) one or more output signals and/or a means of displaying the measured determinand and/or either
the totalized volume and/or volumetric flow-rate. If the CCI does not incorporate a local display, it
shall be possible for an authorized person to obtain the current reading by communicating with the
CCI on site using a portable device, such as a laptop, tablet or smart phone. Communication with a
portable device to display a reading shall not interrupt the measurement and shall not allow the user
to defeat access security features;
e) a means of displaying its operating status, for example, normal operation, stand-by, maintenance
mode or malfunction;
f) a means to return to normal operating mode from maintenance, service or programming mode if no
user interactions have been detected after a defined time period;
g) an audible or visual method of indicating loss of power supply (applies only to CCI operating from an
external power supply), e.g. a relay that fails open;
h) an audible or visual method of indicating when the power supply voltage is below its normal
operating limit (applies only to CCIs operating from a battery);
i) a means for preventing unauthorized resetting of the total recorded volume for abstraction metering
and/or effluent discharge monitoring; a symbol, incorporated into the indication device to show the
flow direction, for bi-directional CCI;
NOTE A pointer rotating clockwise with increasing flow and counter-clockwise with reverse flow is acceptable,
but reliance on an increasing or decreasing total is not.
j) a clear physical marking of the direction of forward flow (in the case of a bi-directional CCI this should
be the direction of flow which gives an increase in the total flow recorded. For a CCI which has been
wet calibrated, this should be the direction of flow in which the CCI has been calibrated);
k) a means to subtract from the indicated volume or to record separately the reverse flow volume, for
a bi-directional CCI;
l) an upstream strainer or filter to protect the CCI, where recommended by the manufacturer;
-1 -1
m) a minimum rated operating range for water conductivity between 50 μS cm to 1200 μS cm for an
electro-magnetic device;
n) a means for displaying the firmware and software versions installed.
6.2 Requirements for associated documentation
The following information shall be incorporated into the associated documentation:
a) operating instructions which cover the full functionality and measurement principle of the CCI. These
instructions shall make clear if they are applicable to specific versions of software or firmware;
b) generic guidance on the time period over which the CCI can operate continuously without requiring
manual adjustment or intervention;
NOTE 1 Automatic routines for cleaning, maintenance or recalibration can be used to maintain performance
within the required limits between manual interventions. It is up to the user to ensure that a suitable regime is
adopted for an individual application.
c) a statement of the types of primary device, where applicable, for which the CCI can compute flow-
rate without the input of data other than the type and dimensions of the primary device and a zero
datum;
d) a statement of whether the CCI is designed to measure flow in both forward and reverse directions;
e) a statement defining minimum up and downstream straight lengths of conduit of uniform section
adjacent to the sensor required to meet the performance requirements of this document;
f) a statement of any limitations on the material of conduit into or onto which the CCI’s sensor can be
installed;
g) a statement of any limitations on the conduit dimensions or shape (including wall thickness or pipe
schedule if appropriate), into or onto which the CCI’s sensor can be installed. If multiple sensors are
required, for example in a large conduit, the number and spacing of those sensors shall be stated;
h) for non-contact velocity sensors, a statement of the minimum and maximum separation distances
from the sensor face to the water surface;
i) a statement of the minimum measurable water depth under free surface conditions (the maximum
measurable water depth is assumed to be full bore), for CCIs intended to operate in partially filled
pipes. The manufacturer shall also state whether the CCI can maintain performance within the
requirements of this document under surcharged conditions. A CCI that can only operate in partially
filled pipe with free surface conditions should be tested in accordance with EN 17694-1 [7];
j) a statement, where appropriate, of the rated operating conditions for water pressure;
k) a statement of the quality (e.g. contaminants, salinity) nature and quantity of particulate or other
material that the CCI can pass whilst maintaining its performance within the limits of this document.
If a minimum level of particulate is required for operation of the CCI, this too shall be stated;
l) a statement of any specific requirements relating to the location or shielding of components
necessary to maintain performance within the limits of this document under varying environmental
conditions;
m) a statement, for electronic CCI, of the rated operating conditions for the power supply;
n) a statement, for electronic CCI, of the rated operating conditions for the signal load impedance on the
analogue output, if present. This shall include any resistive effects of cabling and terminations;
o) a statement of the rated operating conditions for water temperature, ambient temperature and
humidity as appropriate;
NOTE 2 The influence of ambient temperature and relative humidity on the performance of a CCI is tested
(see 7.4 and 9.3.6) over the rated environmental operating conditions.
p) the minimum rated operating range for water conductivity for an electromagnetic CCI;
q) a register table or other appropriate instructions for digital (bus) outputs, to ensure the user is able
to read the correct value(s).
7 Performance requirements
7.1 Expression of performance requirements
Specific requirements are expressed as bias (b), variations in error (X), standard deviation (u) or
expanded uncertainty (U) as shown in Table 1. Not all requirements will apply to every CCI.
Annex A describes in detail how the values are calculated for each requirement.
Table 1 — Expression of performance requirements
Requirement Symbol Expression of requirement
Bias b The mean of the errors measured at each
test point (see Annex A)
Repeatability S The standard deviation of the errors
R
measured at each test point (see Annex A)
Output impedance X
O
Supply voltage
X
V
Ambient air X
T The value to be reported for each individual
temperature
performance requirement, and to be used in
the calculation of the combined
Relative humidity X
RH
performance characteristic, shall be the
Incident light X maximum value obtained (see Annex A).
LX
Direct solar radiation X
SR
Water temperature X
FT
Sensor location X
SL
Stray currents X
SC
Combined performance U An expanded uncertainty obtained by
C
requirement combining uncertainties derived from the
measured errors for the individual
performance requirements. It is expressed
at a 95 % confidence with a coverage factor
taken to be 2 (see Annex A).
7.2 Performance requirements
7.2.1 A CCI shall be capable of meeting the performance requirements of this document over a
measurement ratio of at least 20:1 (maximum measured value: minimum measured value). The minimum
measured value shall be a non-zero value.
7.2.2 Table 2 shows the maximum value for each performance requirement for a CCI as determined by
the tests specified in Clauses 9 and 10. A CCI shall conform with each performance requirement and the
combined performance requirement.
Table 2 — Performance requirements for CCIs
Performance requirement Symbol Test % error
Bias b 9.3.2 ±1,5
a
9.3.2 ±5
Lower limit value for mean error
Repeatability S 9.3.2 1
R
Supply voltage X 9.3.3 0,5
V
Output impedance X 9.3.4 0,5
O
Water temperature X 9.3.5 0,5
FT
Ambient air temperature X 9.3.6 0,5
T
Relative humidity X 9.3.6 0,5
RH
Sensor location X 9.3.7 0,5
SL
Stray currents X 9.3.8 0,5
SC
b
U 2
Combined performance requirement
C
c
- 9.3.15 30 s
Maximum response time
Warm up - 9.2 To be reported
a
The lower limit value for mean error is only applicable from the minimum value to the minimum value plus
10 % of the measurement range.
b
The combined performance requirement is less than the sum of the specified individual performance values
combined in quadrature. This allows for some differences in performance of CCIs with respect to the
individual requirements within an overall combined performance requirement.
c
The response time of a CCI will be assessed over a variation in flow-rate of at least 20 % of the measurement
range.
7.2.3 A bi-directional CCI shall meet the requirements for bias and repeatability for both forward and
reverse flows. See test 9.3.9.
7.2.4 The bias and repeatability of a CCI not designed to measure reverse flow shall meet the
requirements for bias and repeatability following an accidental short-term reversal of flow. See test
9.3.10.
7.2.5 A mechanical CCI shall meet the requirements for bias and repeatability with and without any
ancillary device used to derive an electronic output. See test 9.3.11.
7.3 Data retention
7.3.1 All pre-set data, including calibration and alarm set points and adjustments, shall be retained for
a minimum period of 30 days after disconnection of the power supply.
7.3.2 The totalized volume shall be retained for a minimum period of 30 days after disconnection of the
power supply.
NOTE National regulations can require significantly longer times.
7.4 Environmental requirements
NOTE See test 9.3.6.
A CCI shall meet the performance requirements detailed in Table 2 over its rated ambient temperature
and relative humidity ranges (see 6.2 o)). For CCIs that are used in external locations or in locations where
humidity may be high, the minimum rated operating conditions for an CCI with respect to ambient
temperature should be −10 ° to +50 °C and for humidity 5 % to 95 % including condensation.
7.5 Water temperature requirements
NOTE See test 9.3.5.
The minimum rated operating conditions for water temperature shall be +0,1 °C to +30 °C. A CCI shall
meet the performance requirements for water temperature detailed in Table 2 over its rated water
temperature range (see 6.2 o)).
7.6 Installation influences
7.6.1 General
NOTE See tests 9.3.12 and 9.3.13.
7.6.2 CCIs with insertion electromagnetic sensors shall meet the bias, repeatability and combined
performance requirements detailed in Table 2 when installed in plastic or metal conduits.
7.6.3 CCIs with non-invasive ultrasonic sensors shall meet the bias, repeatability and combined
performance requirements detailed in Table 2 when installed on pipes constructed from plastic and
metal materials including lined pipes.
7.6.4 CCIs with insertion or non-invasive sensors shall meet the bias, repeatability and combined
performance requirements detailed Table 2 when installed in conduits within the manufacturer’s
specified size range.
7.6.5 CCIs for partially filled pipes sensors shall meet the bias, repeatability and combined performance
requirements detailed in Table 2 under both free surface and surcharged flow conditions.
7.7 Field test requirements
7.7.1 General
NOTE See Clause 10.
7.7.2 During the field test, the errors calculated from a minimum of 24 reference measurements shall
be less than or equal to the value of the combined performance requirement detailed in Table 2, in at least
90 % of the paired readings taken.
7.7.3 During the field test the CCI shall have an up-time greater than 95 %.
8 Testing
8.1 General requirements for testing
The tests defined in Clauses 9 and 10 are designed to demonstrate that a CCI conforms with the
performance requirements defined in Clause 7. CCI testing shall be carried out by laboratories that apply
quality management system practices in accordance with EN ISO/IEC 17025 [8] or other equivalent
standards accepted at international level to ensure that the results of testing are acceptable.
The reference methods, simulated inputs or secondary standards for CCI testing listed at Annex B shall
be used as appropriate. The use of simulated inputs or secondary standards shall be recorded and
justified in the test report.
The uncertainty of the reference method shall be included in the calculation of the results for all tests
except where the uncertainty of the reference method is no more than 1/5 of the performance
requirement being tested. Further information is given at Annex C.
Fewer measurements than required by an individual test can be made if this can be justified, e.g. where a
pattern of low variability is supported by statistical analysis. If this approach is adopted it shall be
recorded and justified in the test report.
The CCI shall be maintained, cleaned or recalibrated in line with manufacturer’s instructions prior to any
test, but adjustments shall not be carried out during the course of the test.
Any self-cleaning mechanisms or other automatic maintenance functions shall be disabled during any
laboratory test unless these are part of the normal measurement cycle or the test procedure states
otherwise.
Insertion sensors should be cleaned between tests by rinsing with demineralized water.
Readings shall be allowed to stabilize after any change in an influence quantity or determinand value.
Data from tests shall be processed in accordance with the calculation methods detailed in Annex A.
8.2 Laboratory test conditions
The number of test points depends on the range of the CCI. The measurement range (R) is calculated as:
R = Q / Q
upper lower
where
Q to Q are the minimum and maximum measured values over which the CCI is to be tested.
lower upper
This is equivalent to the R value as defined in EN ISO 4064-1, where Q = Q3 and Q = Q1
upper lower
Q shall be a non-zero value.
lower
For CCIs to be tested over a water velocity range, R shall be calculated using the minimum and maximum
velocities for which certification is sought and a fixed nominal liquid depth or conduit size.
The number and distribution of test points shall be chosen from Table 3.
Table 3 — Test point values
R
Limits of
Test point 20 – 39 40 – 199 200 – 629 630 +
determinand value
1A 1,05 Qlower ± 5 % Y One of One of One of
1B 1,68 Q ± 5 % Y these these these
lower
2A 4 Q ± 5 % - Y Y Y
lower
2B 16 Q ± 5 % - - Y
lower
One of these
2C 0,05 Q ± 5 % - - Y
upper
2 0,2 Q ± 5 % Y Y Y Y
upper
3 0,35 Q ± 5 % Y Y Y Y
upper
4 0,75 Q ± 5 % Y Y Y Y
upper
5 0,975 Q ± 2,5 % Y Y Y Y
upper
In Table 3, test points 1A, 1B, 3, 4 and 5 are designed to correspond to the test points required by
EN ISO 4064-2 where Q corresponds to Q1 and Q corresponds to Q3.
lower upper
Table 4 gives the reference conditions for possible influence quantities. Tests shall be carried out with all
influence quantities at their reference values, including tolerances, unless where specifically varied in any
one test.
Table 4 — Reference conditions
Influence quantity Reference value Tolerance
Ambient air temperature Shall not vary > ± 2,5 °C during
the conduct of each test
Ambient humidity at 20°C non-condensing -
Incident light Existing local light level -
Water temperature Shall not vary > ± 2,5 °C during
the conduct of each test
Water pr
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