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JJG 162-2019: Cold Potable Water Meters
JJG 162-2019
JJG
METROLOGICAL VERIFICATION REGULATION
OF THE PEOPLE’S REPUBLIC OF CHINA
Cold portable water meters
ISSUED ON: DECEMBER 31, 2019
IMPLEMENTED ON: MARCH 31, 2020
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of PRC.
Table of Contents
Introduction ... 4
1 Scope ... 6
2 Normative references ... 6
3 Terms and units of measurement ... 6
3.1 Terms ... 6
3.2 Units of measurement ... 12
4 Overview ... 12
4.1 Principle and structural composition ... 12
4.2 Classification ... 13
5 Metering performance requirements ... 14
5.1 Flow characteristics of water meters ... 14
5.2 Accuracy level and maximum allowable error ... 15
6 General technical requirements ... 15
6.1 Appearance, sign, seal ... 15
6.2 Functions of electronic devices ... 18
6.3 Tightness ... 19
7 Measuring instrument control ... 19
7.1 Verification conditions ... 19
7.2 Verification items ... 22
7.3 Verification method ... 22
7.4 Handling of verification results ... 33
7.5 Verification cycle ... 34
Appendix A Methods for in-use inspection of water meter ... 35
Appendix B Reference format of verification records ... 38
Appendix C Format of the inner pages of the verification certificate and verification
result notification ... 41
Appendix D Classification of water meters ... 42
Appendix E Density lookup table method ... 47
Verification regulation of cold portable water meters
1 Scope
This Regulation applies to the initial verification, subsequent verification, in-use
inspection of cold portable water meters.
The cold portable water meter referred to in this Regulation is a water meter, which has
a temperature grade T30 and T50, measures cold portable water flowing through a
closed full pipe, including water meters whose working principle is based on
mechanical principle, water meters whose working principle is based on electronic or
electromagnetic principle, water meters based on mechanical principle with electronic
device.
2 Normative references
This Regulation makes reference to the following documents:
JJG 164 Verification regulation of standard facilities for liquid flowrate
JJG 643 Verification regulation of flow standard facilities by master meter method
JJG 1113 Verification regulation of verification facility for water meters
JJF 1777-2019 Program of pattern evaluation of cold potable water meters
For any dated references, only the dated version applies to this Regulation; for any
undated referenced document, its latest version (including all amendments) applies to
this Regulation.
3 Terms and units of measurement
3.1 Terms
3.1.1 Water meter
Under measurement conditions, an instrument used to continuously measure, record,
and display the volume of water flowing through the measurement transducer.
Note: The water meter includes at least one measurement transducer, a calculator (including
adjustment or correction device if any), and an indicating device. The three can be placed
An indication value controlled by legal metrology.
Note: If there is a repeated indication, the initial indication of the measurement result is the
primary indication.
3.1.13 Permanent flow rate (Q3)
The maximum flow rate under rated working conditions. At this flow rate, the water
meter shall work normally and meet the maximum allowable error requirements.
Note: In this Regulation, this flow rate is expressed in m3/h.
3.1.14 Overload flow rate (Q4)
The maximum flow rate that requires the water meter to meet the maximum
allowable error requirements in a short period of time and then maintain the metering
characteristics under rated working conditions.
Note: The reference definition of "short period of time" here is "no more than 1 h in a day
and no more than 200 h in a year".
3.1.15 Minimum flow rate (Q1)
The minimum flow rate that requires the water meter to work within the maximum
allowable error.
3.1.16 Transitional flow rate (Q2)
The flow rate that appears between the common flow rate and the minimum flow
rate, dividing the flow range into two zones: "high flow zone" and "low flow zone",
each with a specific maximum allowable error.
Note: Q1 ≤ Q < Q2 is usually called "low flow zone"; Q2 ≤ Q ≤ Q4 is called "high flow zone".
3.1.17 Combination meter changeover flow rate (Qx)
The flow rate Qx1 when the large water meter stops working as the flow rate
decreases, or the flow rate Qx2 when the large water meter starts working as the flow
rate increases.
Note: For the structural features of combination water meters, see D.2.2.5 in Appendix D.
3.1.18 Maximum allowable (working) pressure (MAP)
The maximum internal pressure, that the water meter can withstand under rated
working conditions without deteriorating the metering characteristics.
3.1.19 Working temperature (Tw)
The water temperature in the pipe as measured upstream of the water meter.
Note: Water meters are divided into two temperature grades: T30 and T50, according to the
applicable working temperature range. T30 means the working temperature range is (0.1 ~
30) °C; T50 means the working temperature range is (0.1 ~ 50) °C.
3.1.20 Working pressure (pw)
The average water pressure (gauge pressure) in the pipe, as measured upstream and
downstream of the water meter.
3.1.21 Test flow rate
The average flow rate during the test calculated based on the indication of the
calibrated reference device.
Note: In this Regulation, the test flow rate is the verification flow rate.
3.1.22 Nominal diameter (DN)
The alphanumeric designation of the size of the piping system components, which
is for reference only.
Note:
1 The nominal diameter consists of the letters DN followed by a dimensionless integer,
which indirectly represents the actual size of the inner or outer diameter of the connection
end in millimeters.
2 The number followed by the letters DN does not represent a measurable value and shall
not be used in calculations, except as otherwise provided in the relevant
recommendations.
3 In the recommendations on the use of the DN marking system, any relationship between
DN and component size can be given in the form of DN/OD (outer diameter) or DN/ID
(inner diameter).
3.1.23 Rated operating condition
The operating conditions that need to be met during measurement in order for the
water meter to work according to the design performance.
3.1.24 Electronic device
A device that uses electronic components and performs specific functions, usually
made into an independent unit and can be tested separately.
3.1.25 Converter of mechanical-electric signal
The water meter shall be marked with the type approval sign and number of the
measuring instrument in a prominent position.
Newly manufactured water meters shall have an exit-factory inspection certificate.
6.1.2.2 Marking of measuring instruments
The water meter shall clearly and permanently indicate the following information on
the housing, the dial or nameplate of the indicating device, the inseparable cover, either
centrally or dispersedly:
a) Unit of measurement.
b) Accuracy grade, which may not be marked if it is grade 2.
c) Values of Q3 and Q3/Q1: If the water meter can measure reverse flow and the
values of Q3 and Q3/Q1 are different in the case of forward and reverse flow,
THEN, the values of Q3 and Q3/Q1 shall be described according to the
corresponding flow direction. The ratio Q3/Q1 may be express...