Decree of the Ministry of Industry and Trade No. 334 / 2000 Coll.
Decree of the Ministry of Industry and Trade laying down requirements for cold water meters marked by EEC mark
Valid
Order
Effective from 21.04.2004
334
DECLARATION
Ministry of Industry and Trade
of 6 September 2000
laying down requirements for cold water meters marked by the EEC mark
The Ministry of Industry and Trade provides, pursuant to Section 27 of Act No. 505 / 1990 Coll., on Metrology, as amended by Act No. 119 / 2000 Coll., ("the Act ') for the implementation of Sections 6 (2) and 9 (1) of the Act:
This Decree lays down requirements for cold water meters (hereinafter referred to as "water meters'). For the purposes of this Decree, water is considered to be cold if its temperature is between 0 ° C and 30 ° C.
Water meters may be marked with the EEC type-approval mark and the initial EEC verification mark, the graphic form of which is provided for in the specific legislation, (2) only if they meet the requirements set out in the Annex to this Regulation and the fulfilment of which has been verified by the procedures laid down in the specific legislation.2)
This Regulation shall enter into force on the day of the publication of the sectoral annex to the Protocol to the Europe Agreement establishing an association between the Czech Republic, of the one part, and the European Communities and their Member States, of the other part, on conformity assessment and acceptance of industrial products in the Collection of International Treaties, or on the date of the entry into force of the Treaty of Accession of the Czech Republic to the European Union, if that date is earlier.
Minister:
Doc.
Annex to Decree No 334 / 2000 Coll.
Requirements for water meters
1. TERMINOLOGY AND DEFINITIONS
This annex applies only to water meters based on a direct mechanical principle based on the use of volume chambers with moving walls or on the effect of water speed on the rate of rotation of the moving part (radial or axial turbine).
1.1. Flow
The flow rate is the volume of water flowing through the water meter per unit of time, expressed in cubic metres or litres and time in hours, minutes or seconds.
1.2. Prolonged volume
The elongated volume is the total volume of water that passed through the water meter over a given period of time.
1.3 Maximum flow rate (Qmax)
The maximum Qmax flow rate is the largest flow rate in which the water meter can operate after limited time intervals without damage and without exceeding the maximum permissible error and maximum permissible value of pressure loss.
1.4 Nominal flow rate (Qn)
The nominal flow rate Qn is equal to half of the maximum flow rate Qmax. This flow rate is expressed in cubic metres per hour and is used to indicate the water meter.
At the nominal flow rate Qn, the water meter shall be able to operate in normal use, i.e. under continuous and interrupted operating conditions, without exceeding the maximum permissible errors.
1.5 Minimum flow rate (Qmin)
The minimum Qmin flow rate is the flow rate above which the water meter shall not exceed the maximum permissible error and which is fixed as a function of Qn.
1.6 Flow range
The flow range of the water meter is limited by the maximum and minimum flow rates of Qmax and Qmin. This range is divided into two areas, called upper and lower, with different maximum permissible errors.
1.7 Transition flow (Qt)
The transition flow rate Qt is the flow rate that separates the upper and lower flow ranges and in which the maximum permissible error changes incontinuously.
1.8 Maximum holiday error
The maximum permissible error is the greatest possible error of the water meter authorised for EEC type-approval and for the initial EEC verification under this Regulation.
1.9 Pressure loss
Pressure loss means loss which is caused by the presence of a water meter in the pipe.
2. METROLOGICAL PROPERTIES
2.1 Maximum permissible errors
The maximum permissible error in the lower range from Qmin (inclusive) to Qt (excluding) is ± 5%.
The maximum permissible error in the upper range from Qt (inclusive) to Qmax (inclusive) is ± 2%.
2.2 Metrological classes
Water meters are divided according to the above defined values Qmin and Qt into three metrological classes listed in the following table:
| Třídy | Qn | ||
|---|---|---|---|
| < 15 m3/h | ≥ 15 m3/h | ||
| Třída A | Hodnota: Qmin | 0,04 Qn | 0,08 Qn |
| Hodnot: Qt | 0,10 Qn | 0,30 Qn | |
| Třída B | Hodnota: Qmin | 0,02 Qn | 0,03 Qn |
| Hodnota: Qt | 0,08 Qn | 0,20 Qn | |
| Třída C | Hodnota: Qmin | 0,01 Qn | 0,006 Qn |
| Hodnota: Qt | 0,015 Qn | 0,015 Qn | |
3. TECHNOLOGICAL PROPERTIES
3.1. Construction - General provisions
The waterometer shall be designed in such a way that:
(a) long-term provision of services and guarantees resistance to fraudulent manipulation;
(b) under normal conditions of use, it complies with the provisions of this Decree.
Where water meters may be exposed to an accidental change in the direction of flow, they shall be able to withstand this change without damage and without changing their metrological characteristics while recording this reverse flow.
3.2. Materials
The water meter shall be made of strength and stability materials corresponding to the purpose for which it will be used. The water-meter shall be made entirely of materials resistant to internal and normal external corrosion and, if necessary, shall be provided with appropriate coating. Changes in water temperature within the operating temperature range shall not adversely affect the materials used for the production of the water meter.
tightness - pressure leak
The water meter shall be able to withstand the constant water pressure for which it has been designed and which is known to be the maximum operating pressure for an unlimited period of time, while maintaining the correct function, without leaking water, leaking through walls and permanent deformation. The minimum value of this pressure is 1000 kPa (10 bar).
3.4 Pressure loss
The pressure loss on the whole water-meter shall be measured during the EEC type-approval tests and shall not exceed 25 kPa (0,25 bar) at nominal flow rate and 100 kPa (1 bar) at maximum flow rate.
On the basis of the test results, water meters shall be assigned to one of the four groups with the following maximum pressure loss values: 100; 60; 30 and 10 kPa (1,0; 0,6; 0,3 and 0,1 bar). The relevant value shall be indicated on the EEC type-approval certificate.
3.5 Indicator
The indication device shall allow for reliable, easy and unambiguous reading of the volume of measured water, expressed in cubic metres, by means of a simple and comprehensible grouping of its individual parts. This volume is given by one of the following options:
(a) by the position of one or more indicators on circular scales,
(b) displaying a series of consecutive digits in one or more openings;
(c) a combination of these two systems.
The cubic meter and its multiples must be shown in black; the cubic meter parts must be shown in red.
The optical height of the digits shall not be less than 4 mm.
On digital indicators of types (b) and (c), the vertical upward displacement of all digits shall be visible. The movement of any digital unit shall be completed when the digits of the nearest lower decade change from 9 to 0; the cylinder representing the smallest valid digit may move continuously for type (c). The whole number of cubic metres shall be clearly marked.
Indicators with indicators of type (a) and (c) shall be rotated clockwise. The value of each cut of the scale in cubic metres shall be expressed as 10n, where n is a positive or negative integer or zero, thereby creating a system of consecutive decades. In the vicinity of each part of the scale, the following markings shall be indicated:
| x 1000 | x 100 | x 10 | x 1 | x 0,1 | x 0,01 | x 0,001. |
In both cases (numerical and numerical indicators):
- the symbol of the unit m3 must be displayed either on the code list or in the immediate vicinity of the digital indication,
- the fastest rotating and visually readable numbered element ("control element") shall move continuously; His piece is known as the scale verification piece. The control element may be permanent or created by temporarily adding removable parts. These parts shall not have a significant influence on the metrological characteristics of the water meter.
The length of the scale verification panel shall not be less than 1 mm and shall not be greater than 5 mm. The scale shall include:
(a) marks of the same width which are not more than one quarter of the distance between axes of two adjacent marks which differ only in length; or
(b) contrast strips of a constant width equal to the length of one piece of the scale.
3.6 Number of digits and value of scale verification panel
The indicator device shall be able to record the volume, expressed in cubic metres, of at least 1,999 hours of operation at nominal flow rate without returning to zero.
The value of the scale verification panel shall be 1 × 10n or 2 × 10n or 5 × 10n. In the verification, the value of the panel shall be small enough to ensure that the accuracy of the measurements is not greater than 0,5% (the likely error of reading not more than half of the length of the smallest part of the scale is taken into account) and that the minimum flow rate does not exceed 1 1 / 2 of an hour.
It is possible to add additional equipment (starfish, disc with reference mark, etc.) to show the movement of the measuring instrument before it is clearly visible on the indicator device.
3.7 A control device
The water meter may be equipped with a justice device by which the ratio between the indicated volume and the volume actually flowing can be changed. This device is mandatory for water meters which use the water speed to rotate the moving part.
3.8 Acceleration equipment
The use of an accelerator device to increase the speed of the water meter at flows below Qmin is prohibited.
4. MARKS AND NAMES
4.1 Identification
For all water meters, it is mandatory that they carry the following information in legible and indelible form, either separately or grouped on the water meter housing, on the indicator code list or on the information plate:
(a) the name of the manufacturer or the trade name or trade mark;
(b) metrological class and nominal flow rate Qn in m3 / h;
(c) the year of manufacture and the production number;
(d) one or two arrows indicating the direction of flow;
(e) the EEC type-approval mark,
(f) maximum operating pressure in bars if more than 1000 kPa (10 bar);
(g) the letter "V" or "H" if the water meter can only function correctly in vertical (V) or horizontal (H) positions.
4.2 Location of EEC initial verification marks
For EEC initial verification marks, a space visible without dismantling of the water meter must be reserved on the base part (mostly on the water meter housing).
4.3 Plumbing
The water-meter shall be equipped with protective devices which can be sealed in such a way as to ensure that it is not possible to remove or change the water-meter or its juicing device without damaging the protective equipment before and after the correct installation of the water-meter.
5 EEC TYPE-APPROVAL
5.1. Procedure
EEC type-approval shall be carried out in accordance with a separate legislative act (2).
5.2. Type examination
If it has been established from the attached documentation that the type complies with the provisions of this Decree, then laboratory tests shall be carried out on a number of instruments under the following conditions:
5.2.1. Number of water meters tested
The number of water meters to be submitted by the manufacturer is shown in the table below:
| Jmenovitý průtok Qn, m3/h | Počet vodoměrů |
|---|---|
| Qn ≤ 5 | 10 |
| 5 < Qn ≤ 50 | 6 |
| 50 < Qn ≤1000 | 2 |
| 1000 < Qn | 1 |
5.2.2. Pressure
For metrological tests (paragraph 5.2.4), the pressure at the outlet of the water meter shall be high enough to avoid cavitation.
5.2.3. Test equipment
In general, water meters shall be tested individually and in all cases in such a way as to accurately demonstrate the individual characteristics of each of them.
The Czech Metrology Institute or Authorised Metrology Centre must take all necessary steps to ensure that the relative inaccuracy in measuring the volume of water supplied does not exceed 0,2%, including the inclusion of various causes of error caused by installation.
The maximum permissible inaccuracy is 5% for pressure measurement and 2,5% for pressure loss measurement.
During each test, the relative flow change shall not exceed 2,5% between Qmin and Qt and 5% between Qt and Qmax.
The test equipment must be approved by the Czech Metrology Institute regardless of where the tests are carried out.
5.2.4. Test procedure
The examination shall include the following activities which shall be carried out in the following order:
(a) pressure leak test;
(b) determination of the flow-dependent error curves by detecting the possible pressure effect and including the normal installation conditions specified by the manufacturer for this type of water meter (direct sections of the upstream and downstream pipelines, narrowing, obstacles, etc.),
(c) the determination of the pressure loss;
(d) an accelerated long-term stability test.
The pressure leak test shall consist of two parts:
(a) each water-meter must withstand a pressure of 1600 kPa (16 bar) or 1.6 times the maximum operating pressure applied for 15 minutes without discharging or leaking through the walls (see paragraph 4.1 (f));
(b) each water-meter must withstand a pressure of 2000 kPa (20 bar) or equal to twice the maximum operating pressure applied for one minute without damage or blocking (see paragraph 4.1 (f)).
The results of tests (b) and (c) shall provide a sufficient number of points to ensure that the curves can be reliably drawn in their entirety.
Accelerated long-term stability tests shall be carried out as follows:
| Jmenovitý průtok vodoměru Qn v m3/h | Zkušební průtok | Druh zkoušky | Počet přerušení | Doba trvání přestávek | Doba činnosti při zkušebním průtoku | Doba trvání spuštění a zastavení (sekundy) |
|---|---|---|---|---|---|---|
| Qn ≤10 | Qn | nespojitá | 100 000 | 15 s | 15 s | 0,15 (Qn), minimálně 1 s(*) |
| 2 Qn | spojitá | 100 h | ||||
| Qn>10 | Qn | spojitá | 800 h | |||
| 2 Qn | spojitá | 200 h |
(*) (Qn) is a number equal to the value of Qn expressed in m3 / h.
The measurement errors shall be determined before the first test and after each series of tests; the minimum requirement is to be determined at the following flows:
| Qmin | Qt | 0,3 Qn | 0,5 Qn | 1 Qn | 2 Qn |
In each test, the volume of water flowing through the water meter shall be large enough to turn the indicator or cylinder on the verification scale by one or more full turns and to avoid the effect of the periodic error of data.
5.2.5. Conditions for EEC type-approval
The water-meter type is approved if it meets the following conditions:
(a) corresponds to the administrative, technical and metrological provisions of this Order and its Annex;
(b) the tests (a), (b) and (c) referred to in paragraph 5.2.4 show that they comply with the metrological and technological characteristics of Parts II and III of this Annex;
(c) after completion of each accelerated long-term stability test:
1. no change in relation to the initial curve was observed greater than 1,5% between Qt and Q or more than 3% between Qmin and Qt;
2. the maximum water meter error between Qmin and Qt is ± 6% and between Qt and Qmax is ± 2,5%.
6. FIRST EEC VERIFICATION
This verification shall be carried out at a place approved by the Czech Metrology Institute. The layout of the premises and test equipment shall be such that the verification can be carried out under safe, reliable conditions and without any time loss for the persons responsible for these tests. The provisions of paragraph 5.2.3 shall be complied with, but, if desirable, water meters may be tested in series. If this method is used, the output pressure of all water meters shall be sufficient; Special measures may be taken to prevent cavitation to prevent interactions between water meters.
The complete apparatus may contain automatic devices, bypass valves, flow limiters, etc., provided that each test circuit between the verified water meters and the control tanks is clearly defined and that the internal pressure tightness of these circuits can be checked at any time.
Any type of water supply system may be used, but if several test circuits operate in parallel, there shall be no interaction between them incompatible with the provisions of paragraph 5.2.3.
If the control tank is divided into several chambers, then the separation walls shall be strong enough to ensure that the volume of any chamber does not change by more than 0,2% depending on whether the adjacent chambers are full or empty.
The verification shall include a precision test carried out at least three flows:
(a) between 0,9 Qmax and Qmax;
(b) between Qt and 1,1 Qt,
(c) between Qmin and 1,1 Qmin.
The first of these tests shall include the determination of a pressure loss which should be less than that specified in the EEC type-approval certificate.
Maximum permissible errors are given in point 2.1.
In each test, the volume of water flowing through the water meter shall be large enough to turn the indicator or cylinder on the verification scale by one or more full turns and to limit the effects of the periodic error of data.
If it is found that all errors lie in one direction, then the water meter must be set so that all errors do not exceed half the maximum permissible error.
1) Decree No. 262 / 2000 Coll., which ensures uniformity and correctness of meters and measurements.
2) Decree No. 332 / 2000 Coll., laying down certain procedures for the approval and verification of certain EEC-marked measuring instruments.
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Regulation Information
| Citation | Decree of the Ministry of Industry and Trade No. 334 / 2000 Coll., laying down requirements for cold water meters marked by EEC mark |
|---|---|
| Regulation Type | Order |
| Author | - |
| Collection | Code of Laws |
| Date of Promulgation | 26.09.2000 |
|---|---|
| Effective from | 21.04.2004 |
| Effective until | - |
| Status | Valid |
The regulation text is for informational purposes only.
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