Microsoft Word C036684e doc Reference number ISO 4064 3 2005(E) © ISO 2005 INTERNATIONAL STANDARD ISO 4064 3 Third edition 2005 10 15 Measurement of water flow in fully charged closed conduits — Meter[.]
Preliminary requirements
Before beginning testing, a comprehensive written test program must be developed, outlining key procedures such as assessing measurement error, pressure loss, and wear resistance This program should specify acceptable performance levels and provide clear guidelines on interpreting test results, ensuring accurate and reliable evaluation of the product's performance.
Water quality
Water meter tests must utilize potable water that meets public supply standards or equivalent quality When recycled water is used, appropriate measures should be implemented to prevent residual water in the meter from posing health risks to humans.
The water shall not contain anything capable of damaging the meter or adversely affecting its operation
It shall not contain air bubbles.
Other reference conditions
All other applicable influence quantities, except for the influence quantity being tested, shall be held at the following values during pattern approval tests on a water meter:
Ambient relative humidity range: 45 % to 75 % 1)
Ambient atmospheric pressure range: 86 kPa to 106 kPa (0,86 bar to 1,06 bar)
Power supply voltage (mains a.c.): Nominal voltage (U nom ) ± 5 %
Power supply frequency: Nominal frequency (f nom ) ± 2 %
Power supply voltage (battery): A voltage V in the range; U bmin u V u U bmax
Working water temperature: See ISO 4064-1:2005, 5.4.1, Table 5
Working water pressure: 200 kPa (2 bar)
During each test, the temperature and relative humidity shall not vary by more than 5 °C or 10 % respectively within the reference range.
Location
The environment chosen for the meter tests shall be in accordance with the principles of OIML G 13, and shall be free from unintended disturbing influences, e.g ambient temperature variation and vibration
5 Tests to determine errors of indication
General
The ISO 4064 "collection" method measures water meter errors by collecting the water in vessels and determining the volume volumetrically or by weighing Alternative methods are permitted as long as they meet the accuracy standards specified in ISO 4064 This approach ensures precise assessment of measurement errors in water meters.
Checking facilities of electronic devices is included in this section.
Principle
The checking of the measurement error consists of comparing the indications given by the meter under test against a calibrated reference device.
Description of the test bench
The test bench typically consists of: a) a water supply (mains, non-pressurized tank, pressurized tank, pump, etc.); b) pipework;
1) When the ambient temperature and/or ambient relative humidity exceed the above-mentioned ranges, the effect on the error of indication shall be taken into account
For accurate testing, it is essential to utilize a calibrated reference device such as a calibrated tank or reference meter Precise measurement of test duration requires specific timing instruments, while automation devices streamline the testing process for consistency and efficiency Water temperature and pressure must be monitored using dedicated measuring tools to ensure accurate results If necessary, additional measurements for water density and conductivity should be performed to complete comprehensive testing and analysis.
Pipework
Pipework must include a test section for installing meters, means to establish the desired flow rate, and one or two isolating devices It should also incorporate means for determining the flow rate, along with optional components such as air bleeds, a non-return device, an air separator, and a filter Additionally, provisions are necessary for verifying that the pipework is filled to a specified datum level before and after testing to ensure accurate measurements.
During the test, flow leakage, flow input and flow drainage shall not occur between the meter(s) and the reference device or from the reference device
The pipework shall be such that at the outlet of all meters a positive pressure exists of at least 0,3 bar at any flowrate
The test section comprises the meter(s) along with pressure tappings for accurate pressure measurement, including at least one located upstream of the first meter Additionally, if needed, provisions are included to measure the water temperature at the entry point to the first meter, ensuring comprehensive assessment of flow conditions.
Ensure that all pipe components and devices installed in the measuring section are designed to prevent cavitation and flow disturbances, as these can compromise the accuracy of flow meters and lead to measurement errors Proper selection and installation of measurement equipment are essential for maintaining reliable and precise flow measurements in piping systems.
5.4.3 Precautions to be taken during tests
The operation of the test bench shall be such that the quantity of water which has flowed through the meter(s) equals that measured by the reference device
Ensure that all pipes, including components like the swan neck in the outlet pipe, are filled to the same datum level at both the start and end of the test This is essential for accurate testing and reliable assessment of pipe performance Proper checks guarantee consistency and compliance with testing standards, ensuring the integrity of the piping system.
Air shall be bled from the interconnecting pipework and the meter(s)
All precautions shall be taken to avoid the effects of vibration and shock
5.4.4 Special arrangements for the installation of certain types of meter
This article highlights common causes of errors and essential precautions for installing water meters on test benches, guided by OIML D 4 recommendations Proper installation ensures that hydrodynamic flow characteristics do not affect the meter’s performance and that the overall measurement error remains within specified limits Adhering to these standards helps achieve accurate testing conditions, ensuring reliable and precise water meter performance.
5.4.4.2 Need for straight lengths of pipe or a flow straightener
The accuracy of non-volumetric water meters can be affected by upstream and downstream disturbances caused by the presence and location of elbows, tees, valves or pumps, etc
To ensure accurate testing, the meter under test (MUT) should be installed between straight pipe sections with consistent internal diameters matching the water meter’s connecting ends Installing a flow straightener upstream may be necessary to minimize turbulence and achieve reliable flow measurement Proper installation of the MUT and flow straighteners ensures optimal performance and precise measurement results.
5.4.4.3 Common causes of flow disturbance
Flow can be subject to two types of disturbance, namely velocity profile distortion and swirl, both of which can affect the accuracy of the water meter
See ISO 4064-2 for details of installation requirements
Volumetric water meters, such as oscillating piston and nutating disc meters, utilize measuring chambers with mobile walls, making them highly insensitive to upstream installation conditions As a result, these meters do not require special installation recommendations, ensuring accurate flow measurement regardless of pre-installed pipe configurations.
Velocity type water meters are sensitive to flow disturbance, which can cause significant errors, but the way installation conditions affect their accuracy has not yet been clearly determined
Different types of flow meters may or may not require flow conditioning to ensure accuracy during testing When flow conditioning is necessary, it is essential to follow the manufacturer’s recommendations to achieve reliable results These manufacturer guidelines must be included in the pattern approval documentation to validate the testing process.
These installation requirements should be reported in the pattern approval certificate for the water meter
Concentric meters that are proven to be unaffected by manifold configuration (typically of the volumetric type – see 5.4.4.4) may be tested and used with any suitable manifold arrangement
Meters using electromagnetic induction principles can be influenced by the water's conductivity To ensure accurate measurements, the test water's conductivity must fall within the manufacturer's recommended range.
5.4.5 Test commencement and determination of errors
To ensure reliable test results, adequate precautions must be implemented to minimize uncertainties arising from test bench component operations Specific safety measures are outlined in sections 5.4.5.2 and 5.4.5.3, addressing the two primary cases encountered in the "collection" method, thereby enhancing test accuracy and consistency.
5.4.5.2 Tests with readings taken with the meter at rest
The flow is established by opening a valve situated downstream of the meter, and is stopped by the closure of this valve The meter should be read after registration stops
Time is measured between the start of the opening movement of the valve and the close of the closing movement
During steady-state flow at a specified constant flowrate, the measurement error of the meter varies according to changes in flowrate, following a characteristic measurement error curve Understanding this relationship is essential for accurate flow measurement and calibration.
Flow interruption can lead to measurement errors due to the inertia of moving parts and the rotational movement of water inside the meter, especially in specific types of meters and at certain test flow rates Proper understanding of these factors is essential for ensuring accurate flow measurement and minimizing errors in water meters.
Certain types of meters are particularly sensitive to measurement errors, making it difficult to establish a simple empirical rule that consistently determines when this error can be considered negligible As a result, it is challenging to define universal conditions under which the error can be confidently discounted, highlighting the importance of careful calibration and error assessment for accurate readings.
In case of doubt, it is recommended to increase both the volume and duration of the test to enhance accuracy Additionally, comparing the results with those obtained from other methods, particularly the method outlined in 5.4.5.3, can help eliminate uncertainties and ensure reliable results.
Electronic water meters with pulse outputs used for testing may emit valid pulses after valve closure due to their response to flowrate changes To ensure accurate readings, means must be provided to count these additional pulses.
Calibrated reference device
5.5.1 Overall uncertainty of the actual volume
During testing, the expanded uncertainty of the measured volume must not exceed 20% of the maximum permissible error (MPE) for pattern approval, and 33.3% of the MPE for initial and subsequent verifications, ensuring compliance with accuracy standards.
The evaluation and expression of uncertainty shall be made in accordance with ISO 5168 and the ISO Guide to the expression of uncertainty in measurement (GUM), with a coverage factor k of 2
5.5.2 Minimum volume (volume of the calibrated vessel if this method is used)
The minimum volume permitted depends on requirements determined by the test start and end effects and the design of the indicating device (verification scale division) (see ISO 4064-1).
Meter reading
The maximum interpolation error for a water meter scale does not exceed half a scale division per observation When measuring flow volume with two observations, the total interpolation error can accumulate up to one full scale division.
For digital indicating devices with discontinuous changes of the verification scale, the total reading error is one digit
Major factors affecting the determination of errors of indication
Variations in pressure, flow rate, and temperature on the test bench, along with uncertainties in measuring these physical quantities, are the primary factors influencing the accuracy and error measurement of water meters Accurate assessment of water meter errors depends on controlling and accounting for these variables to ensure reliable calibration results Managing these fluctuations is essential for precise water meter performance evaluation and maintaining measurement standards.
The pressure shall be maintained at a nominally constant value throughout the test at the chosen flowrate
For accurate testing of water meters designated Q 3 u 16 at flow rates of u 0,10 Q 3 , maintaining constant pressure at the inlet is essential This is achieved by supplying the test bench through a pipe from a constant head tank, ensuring a stable and undisturbed flow, which is crucial for precise measurement and reliable test results.
Any other methods of supply shown not to cause pressure pulsations exceeding those of a constant head tank may be used
For all other tests, the pressure upstream of the meter shall not vary by more than 10 %
The maximum uncertainty in the measurement of pressure shall be 5 % of the measured value
Pressure at the inlet to the meter shall not exceed the maximum admissible working pressure (MAP) of the meter
The flowrate shall be maintained nominally constant at the chosen value throughout the test
During each test (excluding start-up and shut-down phases), the flow rate variation must not exceed ±2.5% between Q1 and Q2, and ±5.0% from Q2 (inclusive) to Q4 The flow rate is calculated as the volume passed during the test divided by the elapsed time, ensuring consistent and reliable measurements in flow rate testing. -**Sponsor**As a content creator, I understand the need for SEO-optimized and coherent articles Sounds like you're aiming for precision in defining flowrate variation [Article Generation](https://pollinations.ai/redirect-nexad/FS0o1l00) can help you instantly rewrite articles, ensuring key sentences are highlighted and SEO rules are followed, potentially saving you time and money compared to manual rewriting It ensures flowrate variation stays within ± 2.5% from Q1 to Q2 (exclusive) and ± 5.0% from Q2 (inclusive) to Q4, where flowrate is the volume passed during the test divided by time.
Flowrate variation is acceptable when the relative pressure variation in flow to free air or the relative pressure loss in closed circuits remains within specific limits Specifically, the variation should not exceed ±5% from Q1 to Q2 (not inclusive) and should stay within ±10% from Q2 (inclusive) to Q4 Maintaining these pressure variation thresholds ensures optimal system performance and efficiency.
During a test, the temperature of the water shall not change by more than 5 °C
The uncertainty in the measurement of temperature shall not exceed ± 2 °C
5.7.4 Orientation of meter during error measurements
The position of the meters (spatial orientation) shall be as indicated by the manufacturer and they shall be mounted in the test rig as appropriate
If the meters are marked “H”, the connecting pipework shall be mounted with the flow axis in the horizontal plane during the test (indicating device positioned on top)
If the meters are marked “V”, the connecting pipework shall be mounted with the flow axis in the vertical plane during the test (inlet on lower end)
If the meters are not marked “H” or “V,” a minimum of four meters must be installed in specific orientations: one with the flow axis vertical and flow direction from bottom to top; another with the flow axis vertical and flow direction from top to bottom; at least one with the flow axis at an intermediate angle to the vertical and horizontal, as determined by the approving authority; and the remaining meters with the flow axis horizontal Proper meter placement ensures accurate flow measurement and compliance with testing standards.
Meters with an indicating device integrated into their body must be installed according to specific orientation rules At least one horizontally mounted meter should have its indicating device positioned on the side for optimal visibility, while the remaining meters should be oriented with the indicating device at the top Proper installation ensures accurate readings and compliance with measurement standards.
The tolerance on the position of the flow axis for all meters, whether horizontal, vertical or at an intermediate angle, shall be ± 5°
When testing meters, if fewer than four meters are available, additional meters must be selected from the base population, or the same meters can be repositioned for multiple tests to ensure accurate results.
Intrinsic errors (of indication)
To determine the intrinsic measurement errors of the water meter, focus on evaluating the measurement accuracy at specific flowrates, measuring each error twice for reliability This includes testing the error between Q1 and 1.1 Q1, between 0.5 (Q1 + Q2) and 0.55 (Q1 + Q2) when Q2/Q1 exceeds 1.6, between Q2 and 1.1 Q2, between 0.33 (Q2 + Q3) and 0.37 (Q2 + Q3), between 0.67 (Q2 + Q3) and 0.74 (Q2 + Q3), between 0.9 Q3 and Q3, and between 0.95 Q4 and Q4, to ensure comprehensive accuracy assessment.
If the initial error curve closely aligns with the MPE at a point other than Q1, Q2, or Q3, and this error is representative of the meter type, the approving authority may select an alternative flow rate for initial verification This adjustment can be documented in the pattern approval certificate to ensure accurate and appropriate testing standards.
For each of the above:
1) test the water meter without its supplementary devices (if any) attached;
2) during a test, hold all other influence factors at reference conditions;
3) measure the errors (of indication) at other flowrates if required, depending on the shape of the error curve;
4) calculate the relative error of indication for each flowrate in accordance with Annex A
The observed errors for each of the seven flowrates must not exceed the Maximum Permissible Errors (MPEs) If any meter shows an error greater than the MPE at a specific flowrate, the test at that flowrate must be repeated A test is considered satisfactory if at least two out of three results are within the MPE, and the average of all three test results does not exceed the MPE, ensuring accurate flow measurement.
5.8.2.2 If all the errors of the water meter have the same sign, at least one of the errors shall not exceed one half of the MPE.
Water temperature tests
At reference conditions, the accuracy of at least one meter must be verified at flow rate Q2, with the inlet temperature maintained at (10 ± 5) °C and the maximum admissible working temperature (MAT) This ensures reliable measurement performance under specified operational parameters, aligning with SEO best practices for clear and precise technical documentation.
−5 °C The error of indication (of the meter) shall not exceed the applicable MPE.
Internal pressure tests
At reference conditions, the accuracy of the meter must be verified at a flow rate of Q2, with the inlet pressure maintained at 100 kPa (1 bar) ± 5% The test should be conducted again at the MAP minus 10% The meter's indication error must not exceed the specified Maximum Permissible Error (MPE).
Flow reversal tests
5.11.1 Meters designed for reverse flow
At reference conditions, at least one meter shall be tested at the following reverse flowrates: a) between Q 1 and 1,1 Q 1 ; b) between Q 2 and 1,1 Q 2 ; c) between 0,9 Q 3 and Q 3
The error of indication (of the meter) shall not exceed the applicable MPE
One meter shall also be tested (in reverse flow) for irregularity in velocity fields, according to the provisions of 5.12
5.11.2 Meters not designed for reverse flow
The meter shall be subjected to a reverse flow of 0,9 Q 3 to Q 3 for 1 min
The meter errors shall then be measured at the following forward flowrates: a) between Q 1 and 1,1 Q 1 ; b) between Q 2 and 1,1 Q 2; c) between 0,9 Q 3 and Q 3
The errors of indication shall not exceed the applicable MPE
5.11.3 Meters which prevent reverse flow
The meter should be subjected to the MAP in the reverse flow direction for at least 1 min
The meter errors shall then be measured at the following forward flowrates: a) between Q 1 and 1,1 Q 1 ; b) between Q 2 and 1,1 Q 2 ; c) between 0,9 Q 3 and Q 3
The errors of indication shall not exceed the applicable MPE.
Irregularity in velocity fields tests
Certain types of water meters, such as volumetric meters with measuring chambers and mobile walls—like oscillating piston or nutating disc meters—are known to be unaffected by upstream installation conditions As a result, standard testing procedures are not applicable to these types of meters, ensuring their reliable performance regardless of installation setup.
The purpose of these tests is to verify that the meter complies with the requirements for flow profile sensitivity (see ISO 4064-1)
NOTE 1 The effects on the error of indication of a water meter, of the presence of specified, common types of disturbed flow upstream and downstream of the meter are measured
Types 1 and 2 disturbance devices are employed in testing to generate left-handed (sinistrorsal) and right-handed (dextrorsal) rotational velocity fields, respectively These flow disturbances mimic the typical swirling patterns observed downstream of two right-angled 90° bends Additionally, a Type 3 disturbance device creates an asymmetric velocity profile commonly found downstream of protruding pipe joints or partially opened gate valves.
Using the types 1, 2, and 3 flow disturbers specified in Annex B, determine the meter's indication error at a flow rate between 0.9 Q3 and Q3 under each installation condition outlined in Figure 1 This assessment helps evaluate the accuracy and reliability of the meter across different flow disturbance conditions Properly analyzing these errors ensures compliance with measurement standards and optimal performance in various installation scenarios.
5.12.2.2 During each test, all other influence factors shall be held at the reference conditions
5.12.2.3 For meters where the manufacturer has specified installation lengths of straight pipe of at least
15 × DN upstream and 5 × DN downstream of the meter, no external flow straighteners are allowed
5.12.2.4 When a minimum straight pipe length of 5 × DN downstream of the meter is specified by the manufacturer, only tests 1, 3 and 5 shown in Figure 1 shall be performed
When installing water meters with external flow straighteners, the manufacturer must specify the model, technical specifications, and the exact placement of the straightener within the installation relative to the water meter.
5.12.2.6 Devices within the water meter having flow straightening functions shall not be considered to be a
“straightener” in the context of these tests
Some water meters that have been proven to remain unaffected by flow disturbances both upstream and downstream may be exempted from this testing requirement, as authorized by the approving authority (see 5.12, NOTE).
The error of indication of the meter shall not exceed the applicable MPE for any of the velocity field tests
The above tests without straightener The above tests with straightener
1 type 1 disturber − swirl generator sinistrorsal
4 type 2 disturber − swirl generator dextrorsal
5 type 3 disturber − velocity profile flow disturber a Straight length
Interpretation of results
Where the test programme specifies a single test, the meter shall pass this test if the measured error does not exceed the MPE at the chosen flowrate
Where the test programme specifies that the test shall be repeated, the programme shall specify the rules to be applied for combining the errors obtained
The meter shall pass this test if the error resulting from this combination does not exceed the MPE at the chosen flowrate
Object of tests
These tests aim to ensure that water meters can withstand the designated hydraulic test pressure without leaking or sustaining damage, in accordance with their MAP class as specified in ISO 4064-1:2005 section 5.4.2.
Preparation
6.2.1 Install the meters in the test rig either singularly or in batches
6.2.2 Bleed the test rig pipe-work and the water meter, of air
6.2.3 Ensure that the test rig is free from leaks
6.2.4 Ensure that the supply pressure is free from pressure pulsations.
Test procedure – In-line meters
6.3.1 Increase the hydraulic pressure to 1,6 × MAP of the meter and hold it for 15 min
6.3.2 Examine the meters for physical damage, for external leaks and for leaks into the indicating device
6.3.3 Increase the hydraulic pressure to 2 × MAP and hold it for 1 min The flowrate shall be zero during the test
6.3.4 Examine the meters for physical damage, for external leaks and for leaks into the indicating device
6.3.5 In the course of each test, increase and decrease the pressure gradually without pressure surges
6.3.6 Apply only the reference temperature for this test.
Test procedure – Concentric meters
In the case of concentric meters, the procedure set out in 6.3 shall be followed and, in addition, the seals located at the concentric meter/manifold interface shall be tested to ensure that undisclosed internal leaks between the inlet and outlet passages of the meter do not occur
When the pressure test is carried out the meter and manifold shall be tested together
A pressure of 2 × ∆p is applied to the meter inlet side of the seal
The equipment and method for testing concentric meters may vary according to the design, therefore an example of a test method is given in Annex C
Acceptance criteria
There shall be no visible leakage from the meter or leakage into the indicating device, or physical damage, resulting from any of the pressure tests described in 6.3 and 6.4
Object of test
The purpose of the test is to ensure that the pressure loss for the meter does not exceed 0,063 MPa (0,63 bar) at any flowrate within the range Q 1 to Q 3
The test principle involves measuring the static differential pressure, ∆p2, between the pressure tappings on the measuring section at flowrate Q3 with the meter installed This measurement is used to determine the pressure loss, ∆p1, across the upstream and downstream pipe segments at the same flowrate, but without the meter in place (see Figure 2) This method ensures accurate assessment of pressure drops and flow characteristics at the specified flowrate Q3.
The pressure-loss test procedure must consider pressure recovery downstream of the meter by appropriately positioning the downstream pressure tapping (refer to 7.2.1.2) Additionally, it should account for and compensate the pressure loss caused by the lengths of pipe between the pressure tappings (see 7.3), ensuring accurate and reliable test results.
Preparation
7.2.1 Equipment for pressure-loss test
For pressure-loss tests, essential equipment includes a measuring section of pipework equipped with the water meter under test and a system to generate a consistent flow rate The same constant flow rate used for measuring measurement errors, as outlined in Clause 5, is typically applied during pressure-loss testing to ensure accurate and reliable results.
Pressure tappings of similar design and dimensions shall be fitted to the inlet and outlet pipes of the measuring section
NOTE The upstream and downstream pipe lengths, with their end connections and pressure tappings, plus the water meter on test, constitute the measuring section
7.2.1.2.1 Internal diameter of measuring section
A difference in the diameter of the connecting pipes and that of the meter may result in a measurement uncertainty incompatible with the precision desired and should be avoided
To prevent hydraulic discontinuities and mitigate their impact, water meters must be installed following the manufacturer’s instructions The upstream and downstream connecting pipes in contact with the meter should have internal diameters that match the meter’s connection specifications, ensuring seamless flow and accurate measurement Proper installation and matching pipe diameters are essential for optimal water meter performance and system efficiency.
The internal diameter of the pipes should be specified by the meter manufacturer to ensure accurate measurements Any mismatch between the diameter of the connecting pipes and the meter can lead to measurement uncertainties that compromise precision Therefore, it is essential to avoid differences in pipe and meter diameters to maintain measurement accuracy and reliability.
Straight lengths of pipe must be installed both upstream and downstream of the meter, as well as upstream and downstream of the pressure tappings, following the guidelines illustrated in Figure 2 These straight pipe sections ensure accurate measurement and are specified based on the internal diameter (D) of the pipework in the measuring section Proper installation of these straight pipe lengths is crucial for optimal flow measurement and system performance.
C water meter (for concentric meters, C is the water meter plus manifold)
P 1 and P 2 the planes of the pressure tappings a Flow direction b Measuring section
L W 15 D; L 1 W 10 D; L 2 W 5 D where D is the internal diameter of the pipe-work
Figure 2 — Layout of the measuring section
7.2.1.2.3 Design of measuring-section pressure tappings
Pressure tappings of similar design and dimensions shall be fitted to the inlet and outlet pipes of the measuring section
7.2.1.2.4 Measurement of static differential pressure
Each group of pressure tappings in the same plane shall be connected by a leak-free tube to one limb of a differential pressure measuring device; e.g a manometer or a differential pressure transmitter Provision shall be made for clearing air from the measuring device and connecting tubes.
Test procedure
7.3.1 Determination of pressure loss attributable to pipe lengths for water meters — Measurement 1
To accurately assess pressure loss, measure the pressure difference (∆p 1) of the upstream and downstream pipe sections before testing This involves joining the pipe faces without the flow meter, ensuring no joint protrusion or misalignment, and then measuring the pressure loss across the pipe section at the specified flow rate (see Figure 3a).
The absence of a water meter can lead to a shortened measuring section in the testing setup To compensate for this, if telescopic sections are not installed on the test rig, the gap can be filled by inserting a temporary pipe of the same length and internal diameter at the downstream end of the measuring section Alternatively, the water meter itself can be used to fill the gap, ensuring accurate flow measurement and maintaining the integrity of the testing process.
7.3.1.2 Calculate the pressure loss for the pipe lengths as shown in Figure 3 a)
7.3.2 Measurement and calculation of the actual ∆p of a water meter — Measurement 2
During the same test flow rates used to determine pipe pressure losses within the same installation, with identical pressure tappings and the same differential pressure measuring device, the differential pressure (∆p₂) across the measuring section should be measured with the water meter in position (see Figure 3b).
7.3.2.2 Calculate the overall pressure loss for the pipe lengths + meter using the calculations shown in Figure 3 b)
7.3.2.3 Calculate the actual pressure loss, ∆p, of the water meter at a given flowrate by making the subtraction ∆p = ∆p 2 − ∆p 1
7.3.2.4 If required, the value arrived at may be converted to the pressure loss corresponding to, e.g the
Q 3 of the water meter by reference to the square law formula as follows: pressure loss at Q 3 = [(Q 3 ) 2 /(test flowrate) 2 ] × measured pressure loss
Where it has been established that the pressure loss of the meter will follow the square law, the pressure loss shall be tested at Q 3 only When it is suspected that a pressure loss peak occurs below Q 3 , the pressure loss shall be determined between Q 1 - Q 3 , starting at Q 1 and increasing the flowrate by max 0,1 × Q 3 After Q 3 is reached, the flow rate shall be decreased by max 0,1 × Q 3
7.3.2.5 If the maximum pressure loss is likely to occur at a flowrate other than Q 3 , additional measurements shall be made at the appropriate flowrate using the above procedure,
The maximum expanded uncertainty in the results of the measurement of pressure loss shall be 5 % of the measured pressure loss, with a coverage factor of k = 2.
Acceptance criteria
The pressure loss of the meter shall not exceed 0,063 MPa (0,63 bar) at any flowrate between Q 1 and Q 3 inclusive
∆p 1 = Pressure loss of up and downstream of pipe lengths
∆p 2 = Pressure loss of up and downstream of pipe lengths + water meter
∴ ∆p 2 − ∆p 1 = (∆pL 2 + ∆pL 1 + ∆p meter ) − (∆pL 2 + ∆pL 1 ) = ∆p meter b) Measurement 2
2 water meter in downstream position (or temporary pipe)
3 water meter a Flow direction b Measuring section
Continuous flow test
The purpose of the test is to verify that the water meter is durable when subjected to continuous, permanent and overload flow conditions
The test consists of subjecting the meter to constant flowrate of Q 3 or Q 4 for a specified duration, according to Table 1
The installation consists of: a) a water supply (non-pressurized, pressurized tank; pump; etc.); b) pipework
The pipework for testing must include a flow-regulating device, one or more isolating valves, and a water temperature measuring device at the meter inlet Additionally, it should have means to check the flow rate and duration of the test, as well as devices for measuring pressure at both the inlet and outlet.
The different devices shall not cause cavitation phenomena
The meter and connecting pipes shall be bled of air
Before starting the continuous endurance test, accurately measure the indication errors of the meters at the same flow rates, as specified in section 5.8 Ensure that the meters are mounted either individually or in batches on the test rig in the same orientation used during the intrinsic error determination (refer to section 5.7.4) Proceed with the designated tests to evaluate the meters' performance under continuous operation conditions.
⎯ For meters with Q 3 u 16 m 3 /h, run the meter at a flowrate of Q 4 for a period of 100 h
For meters with a flow rate Q3 exceeding 16 m³/h, conduct endurance testing by running the meter at a flow rate Q4 for 200 hours and at Q3 for 800 hours, ensuring the meters operate within their rated conditions and the outlet pressure prevents cavitation After completing these tests, measure the meter's indication errors at the specified flow rates, then calculate the relative errors for each flow rate Finally, determine the change in errors by subtracting the initial indication error from the post-test measurement, providing essential data on the meter's performance durability.
8.1.4.1 The flowrate shall be kept constant throughout the test at a predetermined level
The relative variation of the flowrate values during each test shall not exceed ± 10 % (except when starting and stopping)
8.1.4.2 The specified duration of the test is a minimum value
The actual volume discharged at the end of the test must meet or exceed the calculated volume, derived from multiplying the specified nominal flowrate by the designated nominal duration of the test This ensures the product's compliance with performance standards related to flow capacity and testing duration.
To satisfy this condition, sufficiently frequent corrections to the flowrate shall be made The flow meters on test may be used to check the flowrate
During the test period, it is essential to record key measurements at least once every 24 hours, or more frequently if the test is segmented into shorter intervals These measurements include water pressure upstream and downstream of the meter(s), water temperature upstream of the meter(s), flow rate, test meter readings, and the volume passed by the meter(s) Regular recording of these data points ensures accurate monitoring and assessment of the test's performance.
After the continuous endurance test: g) The variation in the error curve shall not exceed:
⎯ 3 % for flowrates in the lower zone (Q 1 u Q < Q 2 ) and
⎯ 1,5 % for flowrates in the upper zone (Q 2 u Q u Q 4 )
For the purpose of these requirements the mean values apply h) The error curves shall not exceed a maximum error limit of:
⎯ ± 6 % for flowrates in the lower zone (Q 1 u Q < Q 2 ) and
⎯ ± 2,5 % for flowrates in the upper zone (Q 2 u Q u Q 4 ) for meters intended to meter water with a temperature between 0,1 °C and 30 °C, or
⎯ ± 3,5 % for flowrates in the upper zone (Q 2 u Q u Q 4 ) for meters intended to meter water with a temperature greater than 30 °C.
Discontinuous flow test
NOTE This test is applicable only to meters with Q 3 u 16 m 3 /h and to combination meters, according to Table 1
Period of operation at test flowrate
Duration of start-up and rundown
— a [Q 3 ] is the number equal to the value of Q 3 expressed in m 3 /h
The purpose of the test is to verify that the water meter is durable when subjected to cyclic flow conditions
The test involves exposing the meter to a series of starting and stopping flowrate cycles of short duration, ensuring that during each cycle, the flowrate remains constant at the specified value, Q3 This process evaluates the meter's performance under controlled, repeatable conditions, with the flowrate held steady throughout each cycle to verify accuracy and reliability.
The installation consists of: a) a water supply (non-pressurized, pressurized tank; pump; etc.); b) pipework
The meters may be arranged in series or in parallel, or the two systems may be combined
The pipework system must include the meter(s) along with essential components such as a flow-regulating device per meter line in series, isolating valves, and devices for measuring upstream water temperature It should also feature equipment for checking flowrate, cycle duration, and cycle counts, as well as flow-interrupting devices for each meter line in series Additionally, pressure measurement devices at the inlet and outlet are required to ensure accurate monitoring and system integrity.
The different devices shall not cause cavitation phenomena or other types of parasitic wear of the meter(s)
The meter(s) and connecting pipes shall be suitably bled of air
The flow variation during the repeated opening and closing operations shall be progressive, so as to prevent water hammer
A complete cycle comprises the following four phases: a) A period from zero to test flowrate Q 3 b) A period at constant test flowrate Q 3 c) A period from the test flowrate Q 3 to zero d) A period at zero flowrate
The test programme shall specify the number of flowrate cycles, the duration of the four phases of a cycle, and the total volume to be discharged
Prior to starting the discontinuous endurance test, measure the meters' indication errors at the same flow rates, as outlined in section 5.8 Mount the meters individually or in batches on the test rig, maintaining the same orientation used during intrinsic error assessments (see 5.7.4) During testing, ensure the meters operate within their rated conditions and maintain downstream pressure high enough to prevent cavitation Finally, adjust the flow rate within the specified tolerances to ensure accurate and consistent test conditions.
To ensure accurate flow measurement, operate the meters under the conditions specified in Table 1 After completing the discontinuous endurance test, measure the final errors of indication at the same flowrates described in section 5.8 Calculate the relative errors of indication for each flowrate by comparing the initial and final measurements Subtract the intrinsic error of indication obtained before the test from the post-test error at each flowrate to determine the impact of the endurance test on measurement accuracy. -**Sponsor**Need help making sure your rewritten article is SEO-friendly and captures the essence of each paragraph? It's tough keeping up with content creation! 😅 With [Article Generation](https://pollinations.ai/redirect-nexad/UknFaK3J), you can instantly get 2,000-word, SEO-optimized articles Imagine saving over $2,500 a month compared to hiring a writer! Article Generation can help you focus on key points and ensure your article meets SEO standards.
8.2.3.2 Specific test for combination meters
After undergoing the procedure outlined in section 8.2.3.1, a combination meter must pass an endurance test that simulates real-world service conditions This test involves a discontinuous operation at a flowrate at least twice the change-over flowrate (Qx), determined through increasing flowrates The test includes 50,000 interruptions, each with a 15-second stop and a 15-second running period at the test flowrate Additionally, the acceleration and deceleration phases must last between 3 and 6 seconds to ensure the meter's reliability and durability under repeated operational cycles.
The relative variation of the flow values shall not exceed ± 10 % outside the opening, closing and stoppage periods The meters on test may be used to check the flowrate
The tolerance on the specified duration of each phase of the flow cycle shall not exceed ± 10 %
The tolerance on the total test duration shall not exceed ± 5 %
8.2.4.3 Tolerance on the number of cycles
The number of cycles shall not be less than that stipulated, but shall not exceed this number by more than 1 %
8.2.4.4 Tolerance on actual volume discharged
The actual volume discharged during the test is calculated as half of the product of the specified nominal test flow and the total theoretical test duration, which includes operating periods, transients, and stoppages, with a tolerance of ± 5%.
This level of precision can be obtained by sufficiently frequent corrections of the instantaneous flows and operating periods
During the test, it is essential to record key readings at least once every 24 hours or after each shorter interval if the test is divided accordingly These measurements include upstream and downstream line pressures, upstream line temperature, flow rate, duration of each phase in the discontinuous flow cycle, total number of cycles, meter readings, and the volume passed by the meters Accurate documentation of these parameters ensures comprehensive monitoring of the test's performance and compliance with testing standards.
After the cyclic endurance test: a) The variation in the error curve shall not exceed:
⎯ 3 % for flowrates in the lower zone (Q 1 u Q < Q 2 ) and
⎯ 1,5 % for flowrates in the upper zone (Q 2 u Q u Q 4 )
For the purpose of these requirements the mean values shall apply b) The error curves shall not exceed a maximum error limit of:
⎯ ± 6 % for flowrates in the lower zone (Q 1 u Q < Q 2 ) and
⎯ ± 2,5 % for flowrates in the upper zone (Q 2 u Q u Q 4 ) for meters intended to meter water with a temperature between 0,1 °C and 30 °C or
⎯ ± 3,5 % for flowrates in the upper zone (Q 2 u Q u Q 4 ) for meters intended to meter water with a temperature greater than 30 °C
9 Performance tests for electronic water meters and mechanical meters fitted with electronic devices
Introduction
This clause outlines the performance tests designed to confirm that water meters with electronic devices operate correctly within a designated environment and under specific conditions These tests help ensure the meters function as intended and provide accurate measurements Where applicable, each test specifies the reference conditions used to assess the intrinsic error of the device, ensuring reliability and compliance with standards.
These performance tests are additional to the tests described in Clause 8 and apply to complete meters, to separable parts of a water meter, and, if required, to ancillary devices
When the effect of one influence quantity is being evaluated, all other influence quantities should be held at the reference conditions (see Clause 4)
Pattern approval tests outlined in this section can be conducted concurrently with the tests specified in Clause 8, using the same model of the water meter or its separable parts This approach ensures comprehensive verification of the water meter's compliance while optimizing testing efficiency Conducting these tests in parallel streamlines the approval process and confirms the reliability and performance of both the complete water meter and its individual components.
General requirements
For each performance test, typical test conditions are indicated; they correspond to the climatic and mechanical conditions to which water meters are exposed
Water meters with electronic devices are divided into three classes according to these environmental conditions:
⎯ Class B: for fixed meters installed in a building;
⎯ Class C: for fixed meters installed outdoors;
Applicants for pattern approval can specify particular environmental conditions in their documentation, tailored to the intended use of the meter The metrology service will then conduct performance tests under severity levels matching these conditions, ensuring accurate and reliable measurements These severity levels must be at least Class B to maintain compliance and measurement integrity.
In all cases the metrology service shall verify that the conditions of use are met
NOTE Meters that are approved at a given severity level are also suitable for lower severity levels
Water meters with electronic devices are divided into two electromagnetic environment classes:
⎯ Class E1: residential, commercial and light industrial;
Reference conditions are listed in Clause 4
9.2.4 Test volumes for measuring error of indication of a water meter
Some influence quantities should have a constant effect on the error of indication of a water meter and not a proportional effect related to the measured volume
The influence of the applied load on a water meter is directly related to the measured volume To ensure accurate comparison of test results across different laboratories, the test volume used to measure meter indication error should match the volume delivered in one minute at the overload flow rate Q4.
However, some tests may require more than one minute, in which case they shall be carried out in the shortest possible time, taking into consideration the measurement uncertainty `,,```,,,,````-`-`,,`,,`,`,,` -
9.2.5 Influence of the water temperature
Dry heat, cold, and damp heat tests evaluate how ambient air temperature impacts the performance of electronic meters Additionally, the presence of a water-filled measurement transducer can affect heat dissipation within electronic components, potentially influencing test outcomes.
If a meter has a flow rate value of Q 3 u 16 m³/h, it must operate at the reference flow rate with water passing through it The accuracy of the meter’s indication should be assessed under these conditions, ensuring that the electronic components and measurement transducer are tested under standardized reference conditions.
A simulation of the measurement transducer can be employed to test all electronic components effectively When utilizing simulated tests, it is essential to replicate the effects of water presence on electronic devices typically connected to flow or volume sensors Applying the appropriate reference conditions during these tests ensures accurate and reliable results.
For the purpose of testing, the EUT shall be categorized as one of the cases, A to E, according to the technology described in 9.2.6.2 to 9.2.6.5, and the following requirements shall apply:
⎯ Case A: no performance test (as mentioned in this section) is required;
⎯ Case B: the EUT is the complete meter; the test shall be carried out with water in the volume or flow or volume sensor;
⎯ Case C: the EUT is the measurement transducer; the test shall be carried out with water in the volume or flow or volume sensor;
In Case D, the EUT refers to the electronic calculator, including its indicating device or ancillary components The testing procedure must be conducted using water in the form of volume or flow, or within the volume sensor to ensure accurate assessment.
In Case E, the EUT refers to electronic calculators that include an indicating device or an ancillary device The testing can be conducted using simulated measurement signals, without the presence of water in the volume or flow sensors, or in the volume sensor itself.
Volumetric and turbine water meters can be categorized based on their electronic components and configurations Case A describes meters without electronic devices, while Case B features measurement transducers and electronic calculators housed together In Case C, the measurement transducer is separate from the electronic calculator but includes electronic devices Case D involves a separate electronic calculator with indicating devices, with measurement signals that cannot be simulated Conversely, Case E has a separate electronic calculator and measurement transducer, with the capability to simulate measurement signals, enhancing testing and maintenance options Understanding these configurations is essential for selecting appropriate water metering solutions that comply with standards and optimize measurement accuracy.
Electromagnetic water meters can be classified into four main cases based on their design: Case A features a flow or volume sensor comprising only the pipe, coil, and two meters electrodes without additional electronic devices; Case B has the measurement transducer, electronic calculator, and indicating device integrated within the same housing; Case C separates the measurement transducer, including the flow or volume sensor, from the electronic calculator housed separately; and Case D positions the electronic calculator and indicating device separately from the measurement transducer, with measurement signals not being simulated.
Ultrasonic, Coriolis, and fluidic water meters can be classified based on their design configurations In Case B, both the measurement transducer and the electronic calculator, including the indicating device, are integrated within the same housing, ensuring compactness and ease of installation Case C describes meters where the measurement transducer is separate from the electronic calculator, which is equipped with electronic devices to process measurements In Case D, the electronic calculator and indicating device are separate from the measurement transducer, and it is not possible to simulate measurement signals, emphasizing the importance of device separation for certain applications Proper classification of these water meters is essential for ensuring accurate measurement and compliance with industry standards.
9.2.6.5 Ancillary devices a) The ancillary device is a part of the meter, a part of the measurement transducer or a part of the electronic calculator: Cases A to E
An ancillary device can be classified based on its connection and capabilities relative to the meter In Case A, the ancillary device is separate from the meter but not equipped with electronic components Conversely, in Case D, the device remains separate from the meter, and it is not possible to simulate input signals In contrast, Case E describes a scenario where the ancillary device is separate from the meter but allows for the simulation of input signals, providing additional flexibility and functionality.
Climatic and mechanical environment
Test conditions shall be applied as set out in Table 2
Table 2 — Influence factor: dry heat (non-condensing)
Environmental class: B; C; I Severity level (see OIML D 11): 3 Air temperature: 55 °C ± 2 °C
The purpose of the test is to verify that the meter complies with the requirements in 6.7.5 of ISO 4064-1:2005, during the application of high ambient temperatures
The testing arrangements shall be in accordance with IEC 60068-2-2
Guidance on testing arrangements is given in IEC 60068-3-1 and IEC 60068-1
9.3.1.4 Test procedure in brief a) No pre-conditioning is required b) Measure the error of indication of the EUT at the reference flowrate and at the following test conditions:
1) at the reference air temperature of 20 °C ± 5 °C, before conditioning the EUT;
2) at an air temperature of 55 °C ± 2 °C, after the EUT has been stabilized at this temperature for a period of 2 h;
Measurements should be conducted at a reference air temperature of 20 °C ± 5 °C after the EUT has recovered When assessing the indication error, follow the requirements outlined in section 5.8 Ensure that reference conditions are maintained throughout the test unless specified otherwise Calculate the relative error of indication for each test condition to ensure accurate results.
During the application of the test conditions:
⎯ all the functions of the EUT shall operate as designed and
⎯ the error of indication of the EUT, at the test conditions, shall not exceed the MPE of the “upper zone“
Test conditions shall be applied as set out in Table 3
The purpose of the test is to verify that the meter complies with the requirements in 6.7.5 of ISO 4064-1:2005, during the application of low ambient temperatures
The testing arrangements shall be in accordance with IEC 60068-2-1, IEC 60068-3-1 and IEC 60068-1
The test procedure for the EUT involves not pre-conditioning the device beforehand Measurements should be taken at the reference flow rate—whether actual or simulated—and at the designated reference air temperature To ensure accuracy, the air temperature must be stabilized at either -25 °C for severity level 3 or +5 °C for severity level 1, maintained consistently over a specified period.
To ensure accurate measurement, the error of indication of the Equipment Under Test (EUT) should be measured at the reference flowrate, using either actual or simulated conditions, at an air temperature of −25 °C (severity level 3) or +5 °C (severity level 1) After the EUT has recovered, its indication error should be measured again at the same reference flowrate and temperature The relative error of indication must then be calculated for each test condition Finally, it is essential to verify that the EUT is functioning correctly throughout the testing process.
For measurement transducers included in the Equipment Under Test (EUT), it is essential to maintain the water temperature at the reference temperature when using water in flow or volume sensors Additionally, during error measurement, the installation and operational conditions outlined in Clause 5 must be adhered to, ensuring that reference conditions are applied unless specified otherwise.
During the application of the test conditions:
⎯ all the functions of the EUT shall operate as designed and
⎯ the relative error of indication of the EUT, at the test conditions, shall not exceed the MPE of the “upper zone”
Test conditions shall be applied as set out in Table 4
Table 4 — Influence factor: damp heat, cyclic (condensing)
Upper air temperature: 40 °C ± 2 °C 55 °C ± 2 °C Lower air temperature: 25 °C ± 3 °C 25 °C ± 3 °C
Number of test cycles: 2 a See 9.3.3.4 b).
The purpose of the test is to verify that the meter complies with the requirements in 6.7.5 of ISO 4064-1:2005, after applying conditions of high humidity, combined with cyclic temperature changes
The testing arrangements shall be in accordance with IEC 60068-2-30:1999 and IEC 60068-3-4
The performance, conditioning and recovery of the EUT and its exposure to cyclic temperature changes under damp heat conditions shall be in accordance with IEC 60068-2-30
The test procedure involves several steps to evaluate the EUT's performance under thermal stress conditions First, the EUT is pre-conditioned before testing Next, it is exposed to cyclic temperature variations between 25 °C and 55 °C (for environmental classes C and I) or 40 °C (for class B), with relative humidity maintained above 95% during temperature changes and low-temperature phases, and at 93% during high-temperature phases, ensuring condensation occurs during the temperature rise After this exposure, the EUT is allowed to recover, followed by measuring its error of indication at a reference flow rate The relative error of indication is then calculated to assess measurement accuracy, and finally, it is verified that the EUT functions correctly post-test.
When measuring the errors of indication, the installation and operational conditions shall be in accordance with Clause 5 and the reference conditions shall be applied unless otherwise specified
After the application of the test conditions:
⎯ all the functions of the EUT shall operate as designed and
⎯ the error of indication of the EUT, at the test conditions, shall not exceed the MPE of the “upper zone”
Test conditions shall be applied as set out in Table 5
Test severity (OIML D 11): 2 Frequency range: 10 Hz to 150 Hz
ASD level 10 to 20 Hz: 1 m2s −3 ASD level 20 to 150 Hz: − 3 dB/octave Number of axes tested: 3
The purpose of the test is to verify that the EUT complies with the requirements in 6.7.5 of ISO 4064-1:2005 after the application of random vibrations
The testing arrangements shall be in accordance with IEC 60068-2-64 and IEC 60068-2-47
The test procedure involves mounting the EUT on a rigid fixture in its normal orientation, ensuring gravitational force aligns as in regular use, unless the meter is marked “H” or “V” or gravity is insignificant, allowing any mounting position The EUT is subjected to random vibrations across a frequency range of 10 Hz to 150 Hz along three perpendicular axes, each for 2 minutes, followed by a recovery period Afterward, the EUT is checked for proper functioning and the indication error is measured at a reference flow rate Finally, the relative error of the indication is calculated as specified in Annex A.
For additional requirements, if a flow or volume sensor is integrated into the Equipment Under Test (EUT), it must remain dry and not be filled with water during testing The power supply to the EUT should be turned off during specific testing steps to ensure safety and accuracy During vibration testing, certain conditions must be maintained to ensure proper testing procedures are followed, ensuring the reliability and integrity of the EUT.
⎯ ASD level 10 Hz to 20 Hz: 1 m 2 s −3
The ASD operates within a frequency range of 20 Hz to 150 Hz, with a decrease of -3 dB per octave When evaluating the error of the Equipment Under Test (EUT), it is essential to follow the installation and operational conditions outlined in Clause 5 Reference conditions must be used for measurement accuracy unless specified otherwise.
After the application of the test conditions:
⎯ all the functions of the EUT shall operate as designed and
⎯ the error of indication of the EUT, at the test conditions, shall not exceed the MPE of the “upper zone”
Test conditions shall be applied as set out in Table 6
Number of falls (on each bottom edge): 1
The purpose of the test is to verify that the meter complies with the requirements in 6.7.5 of ISO 4064-1:2005 after the application of a mechanical shock
The testing arrangements shall be in accordance with IEC 60068-2-31 and IEC 60068-2-47
The test procedure requires placing the Equipment Under Test (EUT) on a rigid, level surface in its normal operating position The EUT should then be tilted toward one bottom edge until the opposite edge is 50 mm above the surface, ensuring the tilt angle does not exceed 30° This method helps assess the device's stability and durability under inclined conditions, adhering to testing standards.
To ensure accurate testing, allow the Equipment Under Test (EUT) to freely drop onto the test surface, then repeat the process for each bottom edge Provide the EUT with sufficient recovery time before examining its proper functioning Measure the EUT's indication error at the reference flowrate, and subsequently calculate the relative error of indication to assess measurement accuracy.
Ensure that when the flow sensor is integrated into the Equipment Under Test (EUT), it is not filled with water during disturbance testing Additionally, the power supply to the EUT must be turned off during specific testing steps as outlined, and measurement of indication errors should follow the installation and operational conditions specified in Clause 5, using reference conditions unless otherwise noted For testing purposes, meters that are not marked "H" or "V" should be oriented horizontally, and meters with two reference temperatures should be tested only at their lowest reference temperature.
After the application of the disturbance and recovery:
⎯ all the functions of the EUT shall operate as designed and
⎯ the error of indication of the EUT, at the test conditions, shall not exceed the MPE of the “upper zone”.
Electromagnetic environment
Test conditions shall be applied as set out Table 7
Test voltage (contact mode) 6 kV
Test voltage (air mode): 8 kV
At each test point, at least ten direct discharges shall be applied at intervals of at least 1 s between discharges, during the same measurement or simulated measurement
For indirect discharges, a total of ten discharges should be applied on the horizontal coupling plane, ensuring consistent testing standards Additionally, ten discharges must be performed for each of the different positions on the vertical coupling plane to thoroughly evaluate performance across various configurations These procedures are essential for compliance with safety and testing regulations.
The purpose of the test is to verify that the meter complies with the requirements in 6.7.5 of ISO 4064-1:2005, during the application of direct and indirect electrostatic discharges
The testing arrangements shall be in accordance with IEC 61000-4-2
The test procedure begins by measuring the EUT’s (Equipment Under Test) indication error prior to electrostatic discharge application Next, a 150 pF capacitor is charged using a suitable DC voltage source and discharged through the EUT by connecting the chassis to ground via a 330-ohm resistor, targeting surfaces accessible to the operator, with an optional paint penetration test included if relevant During the discharges, the EUT’s indication error is re-measured to assess changes The error for each test condition is calculated, and the significant fault is determined by subtracting the initial measurement error from the error observed after electrostatic discharges.
During the measurement of the error of indication, the EUT must be subjected to the reference flowrate, ensuring accurate testing conditions If a specific meter design is proven to be immune to electrostatic discharge within the rated operating flowrate, the metrological authority may select a zero flowrate during the electrostatic discharge test All measurements should adhere to the installation and operational conditions specified in Clause 5, with reference conditions applied unless explicitly stated otherwise.
After the application of the disturbance
⎯ all the functions of the EUT shall operate as designed;
The relative error of indication obtained during electrostatic discharge testing must not exceed half of the MPE of the upper zone, ensuring accurate measurements compared to pre-test reference conditions.
⎯ for tests at zero flowrate the water meter totalization shall not change by more than the value of the verification scale interval
Test conditions shall be applied as set out in Table 8
Frequency range: 26 MHz to 1 000 MHz
Modulation: 80 % AM, 1 kHz, sine wave
The purpose of the test is to verify that the meter complies with the requirements in 6.7.5 of ISO 4064-1:2005, during exposure to radiated electromagnetic fields
The testing arrangements shall be in accordance with IEC 61000-4-3 and ENV 50204
9.4.2.4 Test procedure in brief a) The EUT and its external cables of at least 1,2 m length shall be subjected to radiated RF fields b) The preferred transmitting antenna is a biconical antenna for the frequency range 26 MHz to 200 MHz and a log-periodic antenna for the frequency range 200 MHz to 1 000 MHz c) The test is performed as 20 partial scans with vertical antenna and 20 partial scans with horizontal antenna The start and stop frequencies for each scan are listed in Table 9 d) During each scan, the frequency shall be stepped in steps of 1 % of actual frequency, until the next frequency of the table is reached The dwell time at each 1 % step shall be the same The dwell time depends on the resolution of the RVM measurement but shall be equal for all carrier frequencies in the scan
Table 9 — Start and stop carrier frequencies
The determination of the intrinsic error at reference conditions begins at the start frequency and continues until the next frequency listed in Table 9 is reached It is essential to measure the intrinsic indication error of the Equipment Under Test (EUT) under reference conditions prior to applying the electromagnetic field.
To ensure accurate measurement of the EUT's (Equipment Under Test) performance, apply the electromagnetic field according to the required severity level, then start a new measurement to assess the error of indication Adjust the carrier frequency to the next specified value in Table 9, and stop the error measurement Calculate the relative error of indication for the EUT and determine the significant fault by comparing this error to the intrinsic error from initial measurement Change the antenna polarization and repeat the testing steps to verify consistent performance across different conditions These procedures help evaluate the EUT's electromagnetic compatibility and measurement accuracy effectively.
When measuring the indication error of the EUT, it must be subjected to the reference flowrate under conditions specified in Clause 5, unless otherwise noted The installation and operational conditions outlined in Clause 5 should be strictly followed to ensure accurate measurement If a particular meter design is proven to be immune to radiated electromagnetic fields within its rated operating flowrate, the approving authority may select a zero flowrate during electromagnetic susceptibility testing.
After the application of the disturbance
⎯ all the functions of the EUT shall operate as designed;
The relative error of indication measured during each carrier frequency band application must not exceed half of the Maximum Permissible Exposure (MPE) in the upper zone when compared to the pre-test reference conditions at the same flow rate This ensures accurate and reliable measurements, adhering to safety standards.
⎯ during tests applied at zero flowrate, the water meter totalization shall not change by more than the value of the verification scale interval
Test conditions shall be applied as set out in Table 10
Table 10 — Influence factor: influence of a static magnetic field
Type of magnet: ring magnet
Magnetization method: axial (1 north and 1 south)
Coercive force: 100 kA/m to140 kA/m
Intensity of magnetic field measured at less than 1 mm from the surface: 90 kA/m to 100 kA/m
Intensity of magnetic field measured at 20 mm from the surface: 20 kA/m
The purpose of the test is to verify that the meter complies with the requirements in 6.7.5 of ISO 4064-1:2005, under the influence of a static magnetic field
The water meter shall be made operational in accordance with the rated operating conditions
The test procedure involves placing a permanent magnet in contact with the EUT at a location where a static magnetic field could cause indication errors exceeding the MPE and disrupt proper functioning, with the position determined through trial, error, and knowledge of the EUT's construction or previous experience Different magnet positions may be tested to identify the most impactful location Once a test position is established, the magnet is fixed, and the EUT’s indication error is measured at flowrate Q3, following the installation and operational conditions specified in Clause 5, and applying reference conditions unless otherwise noted Meters not marked “H” or “V” are tested with the flow axis in a horizontal orientation, while meters with two reference temperatures are tested only at the lowest temperature For each test, the position and orientation of the magnet relative to the EUT are carefully measured and recorded.
During the application of the test conditions:
⎯ all the functions of the EUT shall operate as designed and
⎯ the indication error of the meter shall not exceed the MPE of the “upper zone”.