ISO 16399:2014

INTERNATIONAL ISO
STANDARD 16399
First edition
2014-05-01
Meters for irrigation water
Compteurs pour l’eau d’irrigation
Reference number
ISO 16399:2014(E)
©
ISO 2014

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ISO 16399:2014(E)

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ISO 16399:2014(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Metrological characteristics . 5
4.1 Maximum permissible error (MPE) . 5
4.2 Metrological characteristics . 5
5 Technical characteristics . 6
5.1 General specifications . 6
5.2 Rated operating conditions . 7
5.3 Materials . 7
5.4 Indicating device . 7
5.5 Reverse flow . 8
5.6 Sealing and security . 8
5.7 Other devices . 9
6 Metrological requirements . 9
6.1 Indicating error . 9
6.2 Internal pressure . 9
6.3 Flow profile sensitivity classes . 9
6.4 Pressure loss .10
7 Performance tests .11
7.1 General conditions for the tests .11
7.2 Static pressure test .12
7.3 Determination of errors .12
7.4 Pressure loss test .14
7.5 Flow disturbance tests .14
7.6 Reverse flow test .17
7.7 Endurance tests .18
8 Tests related to the influence quantities and perturbations .24
9 Marking .24
Annex A (informative) Pulse input solutions .26
Annex B (normative) Flow disturbers .33
Bibliography .47
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ISO 16399:2014(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 23, Tractors and machinery for agriculture and
forestry, Subcommittee SC 18, Irrigation and drainage equipment and systems.
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INTERNATIONAL STANDARD ISO 16399:2014(E)
Meters for irrigation water
1 Scope
This International Standard applies to water meters intended for irrigation use (herein after referred to
as water meters), regardless of the water quality used for this purpose, and specifies the requirements
and certification procedures for water meters, irrespective of the design technologies used to meter the
actual volume of cold water or heated water flowing through a fully charged closed conduit. These water
meters incorporate devices which indicate the integrated volume.
This International Standard also applies to water meters based on electrical or electronic principles
and to water meters based on mechanical principles, incorporating electronic devices used to meter
the actual volume flow of cold water. It provides metrological requirements for electronic ancillary
devices when they are subject to metrological control. As a rule, the ancillary devices are optional.
However national or international regulations make some ancillary devices mandatory in relation to
the utilization of the water meter.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 4064-1:2005, Measurement of water flow in fully charged closed conduits — Meters for cold potable
water and hot water — Part 1: Specifications
ISO 4064-2:2005, Measurement of water flow in fully charged closed conduits — Meters for cold potable
water and hot water — Part 2: Installation requirements
ISO 9644, Agricultural irrigation equipment — Pressure losses in irrigation valves — Test method
ISO 286-2, Geometrical product specifications (GPS) — ISO code system for tolerances on linear sizes —
Part 2: Tables of standard tolerance classes and limit deviations for holes and shafts
ISO 228-1, Pipe threads where pressure-tight joints are not made on the threads — Part 1: Dimensions,
tolerances and designation
ISO/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
water meter
instrument intended to measure continuously, store, and display the volume of water passing through
the measurement transducer at metering conditions
Note 1 to entry: A water meter includes at least a measurement transducer, a calculator (including adjustment or
correction devices, if present), and an indicating device. These three devices may be in different housings.
[SOURCE: OIML R49-1:2006, 2.1.1, modified — The second note is not included here.]
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ISO 16399:2014(E)

3.2
indicating device
part of the meter that provides an indication corresponding to the volume of water passing through the
meter
3.3
actual volume
V
a
total volume of water passing through the meter
Note 1 to entry: The actual volume is calculated from a reference volume as determined by a suitable measurement
standard taking into account differences in metering conditions, as appropriate.
[SOURCE: OIML R49-1:2006, 2.2.1, modified — The phrases “disregarding the time taken” and “This is
the measurand” have been removed from the definition.]
3.4
indicated volume
V
i
volume of water indicated by the meter, corresponding to the actual volume
[SOURCE: OIML R49-1:2006]
3.5
flow rate
Q
volume of water flowing through a device per unit time
3.6
minimum flow rate
Q
1
lowest flow rate at which the meter is required to operate within the maximum permissible error
3.7
transitional flow rate
Q
2
flow rate between the permanent flow rate ≥ 100 ≥ 10 and the minimum flow rate ≥5 that divides the
flow rate range into two zones, the “upper zone” and the “lower zone”, each characterized by its own
maximum permissible error
3.8
permanent flow rate
Q
3
highest flow rate under normal service conditions at which the meter is required to operate in a
satisfactory manner within the maximum permissible error
3.9
overload flow rate
Q
4
highest flow rate at which the water meter is designed to operate for a short period of time within its
maximum permissible error, whilst maintaining its metrological performance when it is subsequently
operated under normal service conditions
3.10
test flow rate
mean flow rate during a test, calculated from the indications of a calibrated reference device
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ISO 16399:2014(E)

3.11
error
measured quantity value minus a reference quantity value
VV−
ia
×100(%)
V
a
3.12
maximum permissible error
MPE
extreme value of error permitted by this International Standard
3.13
working pressure
P
w
average water pressure in the pipe measured upstream of the meter
3.14
durability
ability of a meter to maintain its performance characteristics over a period of use
3.15
metering conditions
conditions of the water, the volume of which is to be measured, at the point of measurement
EXAMPLE Water temperature, water pressure.
3.16
maximum admissible pressure
MAP
maximum internal pressure that the meter can withstand permanently, within its rated operating
conditions, without deterioration of its metrological performance
Note 1 to entry: MAP is equivalent to Nominal Pressure (PN).
3.17
working temperature
T
w
average water temperature in the pipe, measured upstream and downstream of a water meter
[SOURCE: OIML R49-1:2006]
3.18
minimum and maximum admissible temperature
mAT, MAT
minimum and maximum water temperatures that a meter can withstand permanently, within its rated
operating conditions, without deterioration of its metrological performance
Note 1 to entry: mAT and MAT are respectively the lower and upper of the rated operating conditions (ROC).
[SOURCE: OIML R49-1:2006, 2.3.7]
3.19
pressure loss
difference in pressure due to water flow between two specified points in a system or in part of a system
3.20
limiting condition
extreme condition that a meter is required to withstand without damage, and without degradation of its
specified metrological properties, when it is subsequently operated under its rated operating conditions
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ISO 16399:2014(E)

3.21
nominal diameter
DN
numerical designation used to indicate the size of a gated pipe approximately equal to the outside
diameter of the pipe
3.22
influence variable
quantity that, in a direct measurement, does not affect the quantity that is actually measured, but affects
the relation between the indication and the measurement result
3.23
influence factor
influence variable having a value within the rated operating conditions specified for a water meter
3.24
rated operating condition
ROC
operating condition that must be fulfilled during measurement in order that a meter performs as
designed
Note 1 to entry: The rated operating conditions specify intervals for the flow rate and for the influence parameters
for which the errors are required to be within the maximum permissible errors.
[SOURCE: ISO/IEC Guide 99:2007, 4.9, modified — In the definition, the phrase “measuring instrument
or measuring system” has been changed to “meter”. The note is different.]
3.25
reed contact unit
assembly containing contact blades, some or all of magnetic material, hermetically sealed in an envelope
and controlled by means of externally generated magnetic field (e.g. a pulse generator)
3.26
measuring state
state when the switch is closed
3.27
bounce
momentary re-opening of a contact after initial closing, or a momentary closing after initial opening
3.28
bounce time
interval of time between the instant of the first closing (or opening) and the instant of the final closing
(or opening) of the reed contact unit
3.29
operate position time
interval of time between the instant the reed contact unit is in the operate position and the instant of the
removal of the applied magnetic field to the contact
Note 1 to entry: It includes the closing bounce time in a normally open contact or the opening bounce time in a
normally closed contact.
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ISO 16399:2014(E)

4 Metrological characteristics
4.1 Maximum permissible error (MPE)
4.1.1 Formulation
The error is expressed as a percentage, and is equal to:
VV−
()
ia
ε = ×100 (%)
V
a
(1)
where
V is the indicated volume;
i
V is the actual volume.
a
4.1.2 Limits
The maximum permissible error, positive or negative, on volumes delivered at flow rates (Q) between
the minimum flow rate (Q ) (included) and the transitional flow rate (Q ) (excluded) is 5 %.
1 2
The maximum permissible error, positive or negative, on volumes delivered at flow rates between the
transitional flow rate (Q ) (included) and the overload flow rate (Q ) (included) is 2 %.
2 4
— Q ≤ Q < Q , MPE ≤ 5 %
1 2
— Q ≤ Q ≤ Q , MPE ≤ 2 %
2 4
If all the errors within the measuring range of the water meter have the same sign, at least one of the
errors shall be less than one half of the maximum permissible error.
When any accessory part is sold with the water meter, as for instance a control valve, the error shall be
calculated for any position of the accessory, not altering the metrological characteristics of the water
meter.
The maximum permissible error declared by the manufacturer is intended for any recommended
installation configuration.
4.2 Metrological characteristics
4.2.1 Permanent flow rate (Q )
3
3
The value of Q , in (m /h), shall be chosen from the following list:
3
1,0 1,6 2,5 4,0 6,3
10 16 25 40 63
100 160 250 400 630
1 000 1 600 2 500 4 000 6 300
This list may be extended to higher or lower values in the series.
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ISO 16399:2014(E)

4.2.2 Measuring range
The measuring range for the flow rate is defined by the ratio Q /Q . The values shall be chosen from the
3 1
following list:
10 12,5 16 20 25 31,5 40 50 63 80
100 125 160 200 250 315 400 500 630 800
This list may be extended to higher values in the series.
4.2.3 Relationship between permanent flow rate (Q) and overload flow rate (Q )
3 4
The overload flow rate is defined by:
Q /Q = 1,25
4 3
(2)
4.2.4 Relationship between transitional flow rate (Q) and minimum flow rate (Q )
2 1
The transitional flow rate is defined by:
Q /Q = 1,6
2 1
(3)
e.g. Q = 100; Q /Q = 10 (R10); Q /Q = 1,6; Q /Q = 1,25
3 3 1 2 1 4 3
where
3
Q = 100 m /h;
3
3
Q = 10 m /h;
1
3
Q = 16 m /h;
2
3
Q = 125 m /h.
4
5 Technical characteristics
5.1 General specifications
The water meters shall be made so that they
a) guarantee their design useful lifetime and exclude fraud possibility, and
b) fulfil the requirements of this International Standard, under rated operating conditions.
Additional specifications are the following.
— A water meter measures continuously, records and displays the integrated volume of water passing
through the measurement transducer.
NOTE A water meter includes at least a measurement transducer, a calculator, and an indicating device.
— The manufacturer shall specify in the instruction manual the conditions in which the meter can
operate in the event of reversal of the flow direction.
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ISO 16399:2014(E)

— Other ancillary functions of output and input of information (remote reading, prepayment, etc.) may
be included provided they do not affect the performance of the meters as defined in this International
Standard.
— The meter will preferably be designed in such a way as to present as little disturbance as possible to
the water flow and any solid materials it may transport.
— The meter shall be designed such that its operation cannot be affected by a magnetic field as defined
in ISO 4064-1:2005, 7.2.7.
5.2 Rated operating conditions
The rated operating conditions for a water meter shall be as follows:
a) ambient temperature range (T ): 0,1 °C ≤ T < 50 °C;
amb amb
b) pressure (P): P < MAP (maximum admissible pressure);
c) water temperature range [working temperature (T )]: 0,1 °C ≤ T < 30 °C;
w w
d) flow rate range (Q): Q (minimum flow rate) < Q ≤ Q (permanent flow rate);
1 3
e) power supply voltage (mains a.c.): nominal voltage (U ) ± 5 %;
nom
f) power supply frequency: nominal frequency ( f ) ± 2 %;
nom
g) power supply voltage (battery): a voltage, U, in the range; U ≤ U ≤ U .
bmin bmax
5.3 Materials
The water meter shall be fabricated with materials with a resistance and stability suitable for its use.
The meter shall be fabricated using materials which are resistant to internal and external corrosion,
and, if required, will be protected by the application of an appropriate surface treatment.
Water temperature variations within the working temperature range will not adversely affect the
materials used.
5.4 Indicating device
5.4.1 Function
The indicating device shall always guarantee easy reading of volumes without ambiguity.
5.4.2 Unit of measurement
3
The indicated volume of water shall be expressed in cubic metres. The symbols m shall appear on the
dial or immediately adjacent to the numbered display.
5.4.3 Indicating range
This requirement is set in Table 1:
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ISO 16399:2014(E)

Table 1 — Indicating range
Indicating range
Q
3
(minimum values)
3
m /h
3
m
Q ≤ 6,3 9 999
3
6,3 < Q ≤ 63 99 999
3
63 < Q ≤ 630 999 999
3
630 < Q ≤ 6 300 9 999 999
3
5.4.4 Colour coding for indicating devices
The colour black shall be used to indicate the cubic metre and its multiples.
The colour red shall be used to indicate sub-multiples of a cubic metre.
These colours shall be applied to the pointers, indices, numbers, wheels, discs, dials, or aperture frames.
It is allowed to use other manner of indicating the volume for electronic water meters, provided the
volume is expressed in cubic metres, and there is no ambiguity in distinguishing between the primary
indication and alternative displays, e.g. sub-multiples for verification and testing.
5.5 Reverse flow
For meters designed to measure reverse flow, the permanent flow rate and the measuring range may be
different in each direction.
The manufacturer shall specify whether the meter is designed to measure reverse flow. If it is, the reverse
flow volume shall either be subtracted from the indicated volume, or it shall be separately recorded. The
maximum permissible error of 4.1.2 shall be met for forward and reverse flow.
Water meters not designed to measure reverse flow shall either prevent it or they shall be capable of
withstanding an accidental reverse flow without any deterioration or change in their metrological
properties for forward flow, and without modification of the cumulated volume.
5.6 Sealing and security
5.6.1 Meter security and protection against manipulations
Considerations of water meter security and protection against fraud concern only the water meter
including primary indications.
5.6.2 Mechanical protection devices
Water meters shall incorporate protective devices, such as seals, that prevent the water meter from
being disassembled or altered without permanently damaging the seal or the protective device.
5.6.3 Electronic sealing devices
When access to modify parameters that influence the determination of the results of measurements
is not protected by mechanical sealing devices, the protection shall fulfil the provisions described in
ISO 4064-1:2005, 5.8.3.
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ISO 16399:2014(E)

5.7 Other devices
Water meters can incorporate other devices as, for example, reed switches. In such case, the manufacturer
shall ensure that the devices don’t affect the metrological characteristics of the water meter and that
such devices have full compatibility with the water meter.
For example, in order to ensure full compatibility between a reed contact unit and a water meter, the
manufacturer can carry out the tests described in Annex A.
6 Metrological requirements
6.1 Indicating error
The water meters shall be designed so that their indicating errors do not exceed the MPE defined in
4.1.2, under rated operating conditions.
6.2 Internal pressure
The water meters shall withstand the internal pressure they are designed to, while in service, without any
significant influence on the performance characteristics, leaks, exudation, or permanent deformation.
This pressure value is named maximum admissible pressure.
The water meters are classified in function of the MAP declared by the manufacturer, as shown in Table 2:
Table 2 — Water pressure classes
Maximum admissible pressure
Class
(MPa) (bar)
Maximum admissible pressure 6 0,6 6
Maximum admissible pressure 10 1,0 10
Maximum admissible pressure 16 1,6 16
Maximum admissible pressure 25 2,5 25
Maximum Admissible pressure 40 4,0 40
6.3 Flow profile sensitivity classes
The water meter shall be able to withstand the influence of abnormal velocity profiles as defined in
the test procedures of 7.5. During the application of these flow disturbances, the error shall meet the
requirements of 4.1.2.
The water meter manufacturer shall specify the flow profile sensitivity class in accordance with Tables
3 and 4, based on the results of the relevant tests specified in 7.5.
Any flow conditioning section, including straightener and/or straight pipe lengths to be used, shall be
entirely defined by the manufacturer and is considered to be an auxiliary device linked to the type of
the water meter examined.
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ISO 16399:2014(E)

Table 3 — Sensitivity to the irregularity in the upstream velocity profiles classes (U)
Required straight
Class pipe lengths Straightener needed
(x DN)
U0 0 No
U3 3 No
U5 5 No
U10 10 No
U15 15 No
U0S 0 Yes
U3S 3 Yes
U5S 5 Yes
U10S 10 Yes
Table 4 — Sensitivity to the irregularity in the downstream velocity profiles classes (D)
Required straight
Class pipe lengths Straightener needed
(x DN)
D0 0 No
D3 3 No
D5 5 No
D0S 0 Yes
D3S 3 Yes
6.4 Pressure loss
The maximum pressure loss within rated operating conditions shall not exceed 63 kPa (0,63 bar),
between Q and Q . This includes pressure loss in any filter or strainer.
1 3
The pressure loss class is selected by the manufacturer from values taken from the following table:
Table 5 — Pressure-loss classes
Maximum pressure-loss
Class
(KPa) (bar)
ΔP 63 63 0,63
ΔP 40 40 0,40
ΔP 25 25 0,25
ΔP 16 16 0,16
ΔP 10 10 0,10
NOTE Maximum head loss can differ and be higher to the Q corresponding head loss.
3
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ISO 16399:2014(E)

7 Performance tests
7.1 General conditions for the tests
7.1.1 Water quality
Conduct water meter tests using water from the public clean water supply or water that meets the same
requirements.
Ensure that the water does not contain anything capable of damaging the water meter or adversely
affecting its operation. Avoid entrapped air.
7.1.2 Reference conditions
Table 6 — Reference conditions
Condition Admissible range
Water temperature range 4 °C to 35 °C
Working (water) pressure range 0,03 MPa to 1 MPa except DN > 500 that is 0,6 MPa
Ambient temperature range 4 °C to 35 °C
Ambient relative humidity range 35 % to 75 %
Ambient atmospheric pressure range 86 kPa to 106 kPa (0,86 bar to 1,06 bar)
7.1.3 Pressure
Ensure that the water pressure upstream of the water meter does not vary, during the test, by more than
10 %.
Ensure that the pressure at the entrance to the water meter does not exceed the maximum admissible
working pressure (P ) for the
...