CELEX: 51977PC0495
Language: en
Date: 1977-10-18
Title: Proposal for a COUNCIL DIRECTIVE on the approximation of the laws of the Member States relating to HOT-WATER METERS (submitted to the Council by the Commission)

ARCHIVES HISTORIQUES
DE LA COMMISSION
COLLECTION RELIEE DES
DOCUMENTS "COM"
COM (77) 495
Vol. 1977/0157
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 ---pagebreak--- COMMISSION OF THE EUROPEAN COMMUNITIES
                                                  COM(77 ) 495 final .
                                                  Brussels , 18 October , 1977
             . v              Proposal for a
                ■ :          COUNCIL DIRECTIVE
         on the approximation of the laws of the Member States
                             . relating to .    ■     ■,
                             HOT-WATER METERS             "
              ( submitted to the Council by the Commission)
 CCM(77 ) 495 final .
 ---pagebreak---                               EXPLANATORY MEMORANDUM
1.    Genera L
      This directive has been drawn up in pursuance of Article 100 of the
      Treaty and of the Council Directive of 26 July 1971 on the approximation
      of the laws of the Member States relating to common provisions for both
      measuring instruments and methods of metrological inspection ( 1 ).
      It is aimed at guaranteeing the access to the entire Common Market of hot
      water meters which satisfy the prescriptions of this Directive .
      It is also designed to prevent the creation of new obstacles through the
      introduction of different laws , regulations or administrative provisions
      Member States which so far have no national legislation on the subject .
      A comparative study of the rules applicable to hot-water meters has
      revealed differences in the technical specifications for construction
      and use , as well as in the classes of accuracy and the methods of
      inspection to which these meters are subject before they can be marketed
      and put to use .
      As the present national laws are justified by the legitimate wish to
      protect the consumer and the user , the harmonization of these laws
      has emerged as the only likely means of overcoming the difficulties
      caused by the discrepancies , and of creating the conditions necessary
      for the establishment of the common market .
      Furthermore , the harmonization of the laws relating to hot-water meters
      is in line with the general policy of aimed at the rational use of
      energy to which not only the nine Member States but also the majority
      of industrialized countries are committed .
      The rise in the price of oil over the last few years has led most of
      these countries to review their consumption forecasts with a view to
      cutting down expenditure . Efforts have been made in most branches of
      industry either to cut down consumption or to rationalize the use of
      energy .
      At the same time , demographic developments , urbanization , advances in
      hygiene and life-style and finally the process of industrialization
      have been demanding ever greater quantities of water , and in particular
      of hot water .
      Although for many years the local distribution services , both public
      and private , were able to adopt varying criteria for the supply of their
       customers , the time has come when this kind of laxity is no longer per­
      mitted , since present–day market conditions have made hot water a
       costly product .
      Moreover , the efforts to protect the consumer that have been undertaken
      over the past few years have resulted in most of the Member States
      exercising stricter control over the quantities of water used by having
      meters installed on each consumer 's premises .
( 1 ) O.J. N° L 202 of 6 September 1971 , page 1 .
 ---pagebreak---                                    -2-
   ALL these considerations underline the importance of harmonization ,
   which , apart from furthering the main objectives of the CounciL with
   regard to the free movement of goods and greater protection for the
   consumer , wiLL aLso enabLe better cantroL to be exercised over the
   energy consumed .
   Once this directive has been adopted by the CounciL , the Commission
   wiLL be abLe to put forward a proposaL in connection with thermal
   energy meters , the need for which is being feLt ever more acutely .
   Since , in most cases , the hot-water meters covered by this proposal
   are one of the main components of thermal energy meters , the work
   of harmonizing the Latter will be facilitated by the fact that the
   hot-water meters will already have been harmonized when the directive
   on thermal energy meters is adopted .
2. Structure of the directive
   Like most of the directives already adopted by the Council in the
   measuring instruments sector , this directive comprises a legal
   instrument and a technical annex .
   The specifications contained in the annex define the main concepts to
   be employed , and list all the characteristics which hot-water meters
   must possess and the tests they must successfully undergo before they
   can move freely within the Community .
3. Harmonization solution
   As in most of the special directives in this field , the harmonization
   solution that has been adopted is the one known as " optional ". This
   solution is permitted , along with " total " harmonization , by the Council
   Directive of 26 July 1971 relating to common provisions for both mea­
   suring instruments and methods of metrological control .
   Until such time as the main non-technical provisions have been
   harmonized - especially those relating to the use of hot-water meters
   and the inspection charges - the solution of total harmonization is li­
   kely to raise serious problems .
   Optional harmonization means that hot-water meters conforming to this
   directive could be marketed freely between Member States and within
   Member States in the same way as meters that comply with national
   requirements can be marketed in the particular State concerned .
4. Consultation of the Parliament and the Economic and Social Committee
   The opinion of these two bodies is required under the provisions of
   Article 100 ( 2 ). For some Member States , the implementation of the
   provisions of the directive will require an amendment to their national
   laws .
 ---pagebreak--- THE COUNCIL OF THE EUROPEAN COMMUNITIES ,
Having regard to the Treaty establishing the European Economic Community ,
and in particular Article 100 thereof ,
Having regard to the proposal from the Commission ,
Having regard to the opinion of the European Parliament ( 1 ),
Having regard to the opinion of the Economic and Social Committee ( 2 ),
Whereas in the Member States the construction and the methods of inspecting
hot-water meters are subject to mandatory provisions which differ from one
Member State to another and consequently hinder trade in such instruments ;
whereas it is therefore necessary to approximate these provisions ;
Whereas Council Directive - 71 / 316/ EEC         of 26 July 1971 on the appro­
ximation of the laws of the Member States relating to common provisions
for both measuring instruments and methods of metrological control ( 3 ), as
amended, by the Act of Accession (4), laid down the ESC pattern approval and
EEC initial verification procedures ;       whereas , in accordance with that Dir­
ective , there should he laid down the technical requirements relating to
the design and functioning which hot-water meters must satisfy in order to
be freely imported, marketed and used , after inspection and the affixing of
the appropriate signs and marks ,
HAS ADOPTED THIS DIRECTIVE :
                                      Article 1
This Directive shall apply to hot-water meters intended for the continuous
determination of the volume of hot-water passing through them . Such meters
shall be provided with a measuring device linked to an indicating device .
For the purpose of this Regulation , hot water shall be water , the tempera---
ture of which exceeds 30°C but does not exceed 90°C .
                                      Article 2
Hot-water meters to which the EEC marks and signs may be affixed are des­
cribed in the Annex to this Directive .
They shall be subject to EEC pattern approval and shall be submitted for
 EEC initial verification .
                                      Article 3
 No Member State may refuse, prohibit or restrict the placing on the market
 or entry into service of hot-water meters bearing the EEC pattern approval
 and the EEC initial verification mark , on the grounds of their metrological
 properties .                                                              ./...
 ( 1 ) O.J. N° C ,
 ( 2 ) O.J. N° C ,
 ( 3 ) O.J. N° L 202 , 6 . 9.1971 , p.l
 C4 ) O.J. N° L 73 , 27 . 3.1972, p.14
 ---pagebreak---                                   Article 4
1„  Member States shall "bring into force the laws , regulations and
    administrative provisions needed in order to comply with this
    Directive within 18 months of its notification and shall forthwith
    inform the Commission thereof .
2.   Furthermore , after notification of this Directive ,
         Member States shall ensure that the Commission is informed , in
    time for it to submit its comments , of any draft laws , regulations
    administrative provisions which they intend, to adopt in the field
    covered by this Directive .
                                  Article 5
This Directive is addressed to the Member States .
Done at Brussels ,
 ---pagebreak---                                 ANNEX
TERMINOLOGY AND DEFINITIONS
1.0     This Annex applies only to hot-water meters based on a direct ^
        mechanical process involving the use of volumetric chambers with
        mobile walls or the action of the velocity of the water on the
        rotation rate of a moving part ( turbine , impeller etc .)
1.1 .   Flowrate .
        The flowrate is the volume of water passing through the meter
        per unit of time .
1.2 .   Volume delivered .
        The volume delivered is the total volume of water which has
        passed through the meter in a given time .
1.3 .   Maximum flowrate (Q      ).
        The maximum flowrate , Q  max
                                       is the highest flowrate at which the
        meter can function over limited periods without damage , and
        without exceeding the maximum permissible errors and the maximum
        permissible value for loss of pressure .
 1.4 .   Nominal flowrate (Q )
         The nominal flowrate , Qn , is equal to half the maximum flowrat
         Q       It i s expressed in cubic metres per hour and is used to
           max
         designate the meter .
         At the nominal flowrate , Q , the meter should be able to function
         in normal use , i.e. , in continuous and intermittent operating
         conditions , without exceeding the maximum permissible errors .
 1.5 .   Minimum flowrate (Q . ).
         The minimum flowrate , Qmin, is the flowrate above which the
          meter must not exceed the maximum permissible errors , and is
          fixed as a function of Q
  1.6 .   Flowrate range .
          The flowrate range of a water meter is bounded by themaximum
          and minimum flowrates, G>max and Q^. It is divided into two
           regions , termed upper and lower, with different maximum permissi­
           ble errors .
  1.7 . Transitional flowrate (Qt ).
           The transitional flowrate , Qt , is the flowrate which divides the
           upper and lower regions of the flow range and the rate at which
           the maximum permissible errors become discontinuous .
 ---pagebreak---                                         "»4~
    1.8 .   Maximum permissible error .
            The maximum permissible error is the limit of the error permitted
            by this Directive for EEC pattern approval and EEC initial
            verification of a water meter .
    1.9 .   Loss of pressure .
            Loss of pressure means the loss with is caused by the presence
            of the water meter in the conduit .
II . METROLOGICAL CHARACTERISTICS
    2.1 .   Maximum permissible errors .
            The maximum error permitted in the lower region , from Q .
                                                                        mm
            inclusive to Q    non-inclusive , is _+ 5/..
            The maximum * error permitted in the upper region , from
            inclusive to Q max inclusive , is –  + 3% .
    2.2 .   Metrological classes .
            Hot-water meters are divided according to the values of Q .       and
                                                                          min
                defined above , into the four metrological classes in the
            following table :
                                                                                ––
                                            ;             Q
                C lasses                    !               0
                                              < 15m3/ h         ">15m /h
     Class . 0
            Value of Q    .                     0,08  Qn           0,16  Qn
                         min                     '                  '
            Value of Q                          0,15  Qn           0,30  Qn
                                                 '                  '
                                                                                    1
                                                                                    i
     Class A
            Value of Q    .                     0,04 Q             0,08 Qn
                         min                            η
          ' Value of Q                          0,10
                                                 '    Qn           0,20 Q η
     Class B
            Value of Q    .                     0,02 Q             0,04  Qn
                         min                            η           '
            Value of Q                          0,08  Qn           0,15  Qn
                                                 '                  '
     Class C
            Value of Q .                  i     0,01  Qn           0,02 Q n
                         min              j      '
            Value of G>                    ;    0,06
                                                 '
                                                      Qn           0,10 Q n       |î
                                                                        ./...
 ---pagebreak---                                            -5-
/ III . TECHNOLOGICAL CHARACTERISTICS
        3.1 . Construction – General provisions .
              The meters must be constructed in such a way as to :
              ( 1 ) give long service and guarantee proof against fraud ,
              ( 2 ) conform with the provisions of this Directive , under
                     normal conditions of use .
              Where meters may be subjected to an accidental reversal of
              flow they must be capable of withstanding it without any
              deterioration or change in their metrological properties ,
              and at the same time should record such a reversal .
        3.2 . Materials .
              The water meter must be made of materials of adequate strength
              and stability for the purpose for which the water meter is to be
              used .     It must be constructed throughout of materials which are
              resistant to internal and normal external corrosion and if ne­
              cessary be protected by some suitable surface treatment . Water
              temperature variations within the temperature range 0° - 110° C
              must not adversely affect the materials used in the construction
              of the water meter .
        3.3 . Soundness - pressure tightness and temperature resistance .
              A meter must be able to withstand constantly - without defects
              in its functioning , leakage , seepage through the walls or perma­
              nent deformation - a continuous water temperature of 90° C and the
              pressure for which it is designed , termed the maximum operating
              pressure . The minimum value for this pressure is 10 bars .
        3.4 . Loss of pressure .
              Loss of pressure through the meter is determined by EEC pattern
              approval tests , and must not exceed 0.25 bars at the nominal
              flowrate and one at the maximum flowrate .
              On the basis of the test results meters are divided into one of
              four groups with the following maximum values for pressure loss :
              1 , 0.6, 0.3 and 0.1 bars . The relevant value must be indicated
              in the EEC pattern approval certificate .
        3.5 . Indicating mechanisms .
              The indicator must allow , by simple juxtaposition of its various
               constituent elements , a reliable , easy and unambiguous reading of
               the volume of water measured , expressed in cubic metres . The volu­
               me must be given either by :
               ( a ) the position of one or more pointers on circular scales ;
               ( b ) reading off a row of in-line consecutive digits in one or more
                      apertures ;
               ( c ) a combination of these two systems .
 ---pagebreak---                                    ~6~
        A cubic metre and its multiples are indicated in black , and
        sub-multiples of a cubic metre in red .
       The actual or apparent height of the digits must not be less than
       4mm .
       On digital indicators ( types ( b ) and ( c )) visible displacement
       of all digits must be upwards in value . The advance of any
       given digital unit must be completed while the digit of the
       immediately next lower value describes the last tenth of its
       course .
       The roller showing the digits of the lowest value may move con­
       tinuously in the case of type ( c ). The whole number of cubic
       metres must be clearly indicated .
        Indicators with pointers ( types ( a ) and ( c ) should rotate in a
        clockwise direction .   The value in cubic metres for each scale
       division should be expressed as 10 , where n is a positive or
       negative whole number or zero , thereby establishing a system of
       consecutive decades . Data such as the following should be shown
       near each part of the scale : x 1000 - x 100 - x 10 - x 1 -
       x 0.1 - x 0.01 - x 0.001 .     .
        In both cases ( dial and digital indicators ) :
       - the unit symbol m^ should be shown either on the dial or in
           the immediate vicinity of the digital indication ;
       - the fastest-moving visible graduated element - the monitoring
           element ( the scale interval of which is known as the 'verifi­
           cation scale interval' ) - should move continuously . This moni­
           toring element may be permanent or may be fitted temporarily
           by adding detachable parts . These parts must not have any
           significant influence on the metrological properties of the
           meter .
       The length of the verification scale interval should be not less
       than 1mm and not more than 5mm .    The scale shall consist :
       - either of lines of equal thickness not exceeding one quarter
           of the distance between the axes of two consecutive lines and
           differing only in length ;
       - or of contrasting bands of a constant width equal to the length
           of the scale division .
       However , until 19 June 1981 :
      .( a ) the downward movement of digits will be permitted , this
             movement being indicated by an arrow ;
       ( b ) the length of the scale division may be 0.8mm .
3.6 . Number of figures in the verification scale division and their
       values .
       It must be possible for the indicating device to record a volume ,
       expressed in cubic metres , corresponding to at least 1 999 hours'
       operation at the nominal flowrate , without returning to zero .
       The size of the verification scale division must be based on the
       formula 1 x 10n or 2 x 10n or 5 x 10n .      During verification , it
       must be small enough to ensure a measurement inaccuracy of not
       more than 0.5% ( allowing for a possible reading error of not
 ---pagebreak---                                   -7*
      more than half the Length of the smallest scale division ) and
      small enough so that at the minimum flowrate the test does not
      take more than 1h30 .
      A supplementary device ( star , disc with a reference mark , etc )
      may be added in order to show the movement of the measuring
      device before thisjDecomes clearly visible on the indicator .
3.7 . Adjusting device .
      The meters may be fitted with an adjusting device with which it is
      possible to alter the relationship between the volume indicated
      and the volume actually passed . This device is compulsory for
      meters which use the action of the velocity of the water on the
      rotation of a moving part .
3.8 . Accelerating device .
      The use of an accelerating device for increasing the speed of the
      meter below Q .    is prohibited ,
                    mm
3.9 . Additional devices .
      Meters may include a pulse-generating device provided that the
      device does not appreciably affect their metrological properties .
      The pattern approval certificate may provide for the addition
      of special fixed or detachable devices to permit automatic
      verification of the meters .
 ---pagebreak---                                          -8-
IV . MARKS AND INSCRIPTIONS
     4.1 . Identification inscriptions .
           ALL meters must have cLearLy and indelibly inscribed upon them
           the foLLowing items of information , which may be either grouped
           together or entered at separate points on the casing , the indi­
           cator diaL or the data pLate :
           ( a ) the manufacturer 's name or trade name or his trademark ;
           ( b ) the metroLogicaL cLass and nominaL fLowrate Q in cubic
                 metres per hour ;
           (c)   the year of manufacture and the individual production number ;
           (d)   one or two arrows showing the direction of fLow ;
           Ce )  the EEC pattern approvaL mark ;
           (f)   the maximum operating pressure in bars , where this may
                 exceed 10 bars ;
           ( g ) the maximum operating temperature in the form : 90°C ;
           ( h ) the Letter 'V 1 or 'H * if the meter can operate properLy onLy
                 in the verticaL ( V ) or horizontaL ( H ) position .
     4.2 . Positioning of verification marks .
           Space for the EEC verification marks shouLd be provided on an
           essentiaL part ( normaLLy the meter casing ), which is visibLe
           without dismantling .
     4.3 . SeaLmg .
           Meters must be fitted with protective devices which can be
           seaLed in such a way as to ensure , both before and after
           instal Lation , that neither the meter itseLf nor its adjusting
           device can be dismantled or altered without damaging the pro­
           tective devices .
 ---pagebreak---                                             -o-
V. EEC PATTERN APPROVAL .
   5.1 .       Procédure .
               The EEC pattern approval procedure will be carried out in accor­
               dance with Directive N° 71 / 316/ EEC .
   5.2 .       Pattern tests .
               When it has been ascertained from the application file that the
               pattern conforms to the provisions of this Directive , laboratory
               tests will be carried out on a number of instruments under the
               following conditions :
   5 . 2.1 . Number of meters to be tested .
               The number of meters to be submitted by the manufacturer is as
               shown in the following table :
                      Nominal flowrate , Q , m /h         Number of meters
                   Under 1.5                                      10
                   Not less than 1.5
                   but less than 15                                3
                   Not  less than 15                               2
               Depending on how the tests progress , additional specimen meters
               may be required .
   5 . 2 . 2 . Pressure .
               For the metrological tests ( item 5.2.4 .), the pressure at the
               meter outlet should be sufficiently high to prevent cavitation .
   5 . 2 . 3 . Test equipment .
               In general , meters shall be tested individually and , in all cases ,
               in such a way as to demonstrate accurately the individual
               characteristics of each .
               The metrological service of the Member State shall take the
               necessary steps to ensure that the maximum relative inaccuracy
               in measuring the volume of water delivered does not exceed
               0,3% after allowance is made for the various causes of error in
               installation .
               The maximum permissible inaccuracy is 5% in the case of measure­
               ment of pressure and 2.5% in the case of measurement of loss of
               pressure .
                During each test , the relative variation in the flowrates must not
               exceed 2.5% between Q min  . and Q.t and 5% between Q i and Q mmax .
                The maximum permissible inaccuracy in the measurement of tempera­
               ture is 1°C .
                The equipment must be approved by the metrological service of the
               Member State concerned no matter where these tests are carried out .
    5 . 2.4 . Test procédure .
                The tests comprise the following operations , carried out in the
                order shown :
                ( 1 ) pressure tightness test ;
                                                                               •/ • ■ ■
 ---pagebreak---                                                - 10-
                 ( 2 ) determination of the error curves on the basis of the
                       flowrate by ascertaining the effect of the pressure and
                       temperature and taking into account the normal installation
                       conditions for this type of meter ( straight sections of
                       piping upstream and downstream of the meter , constrictions ,
                       obstacles , etc ) stipulated by the manufacturer ;
                 ( 3 ) determination of pressure losses ;
                 ( 4 ) accelerated endurance test ;
                 ( 5 ) a thermal shock resistance test |or meters with a nominal
                       flowrate Q       of not more than 10m / h .
                                    n
                       The pressure tightness test is conducted in two parts at
                       85   (+ 5)°C   :
                       ( a ) each meter should be able to withstand , without
                             leakage or seepage through the walls , a pressure of
                             16 bars or 1.6 times the maximum operating pressure ,
                             applied for a period of 15 minutes ( see item 4.1 ( f ));
                       ( b ) each meter should be able to withstand , without any
                             damage or blockage , a pressure of 20 bars or twice the
                             maximum operating pressure , applied for a period of one
                             minute ( see item 4.1   ( f )).
                       The results of tests ( 2 ) and ( 3 ) should provide a suffi­
                       cient number of points to enable the curves to be plotted
                       accurately throughout the operating range .
                       The accelerated endurance test is to be carried out as
                       follows    :
Nominal         Test flowrate ' Type          Number      Duration   Penod    Duration of
f lowrate       and                  of       of          of         of opé­  start-up
of meter        temperature          test     inter­      pauses     ration   and
                                              ruptions               at  test rundown
                                                                     flowrate ( sec . )
Q ^ 10m /h      Q
                  n
                                     di s~    100000         15 s       15 s  0,015 (Q )*
                                                                                        n
                                     conti­
                and
                                     nuous                                    minimum 1   s
                ( 50 + 5)°C
                Q                     conti­
                  max
                                     nuous                            100 h
                and
                ( 85 _+ 5)°C
              i
              I
Q ^ 1.0m /h     Q
                  n
                                     conti­
                                     nuous
                and
                ( 50 + 5)°C                                           500 h
                Q                    conti­
                  max
                                     nuous
                and
                ( 85 + 5)°C                                           200 h
                                                                   ι
* (Q n ) is a number equal to the value of Q n expressed in m / h .
 ---pagebreak---                                      - 11-
        Before the first test and on completion of each test series the
        measuring errors must be determined , as a minimum requirement ,
        at the following flowrates :
                        Q  .   – Q    - 0.5 Q       - Q
                          min      t             n      max
        In each test , the volume of water passed through the meter must
        be sufficient to rotate the pointer or the roller on the veri­
        fication scale through one or more complete revolutions and
        to eliminate the effects of cyclic distortion .
        The thermal shock resistance test shall be carried out at
        25 cycles as follows :
            Water temperature                 Q                  Duration
                 90°C                      Q                 I       8 min.
                                             max
                                           0                     1 - 2 min.
                 15°C                      Q                         8 min.
                                             max
                                           0                     1 - 2 min.
5.2.5 . Conditions for EEC pattern approval .
        A water meter pattern shall be approved if :
        ( a ) it conforms with the administrative , technical and
              metrological provisions of this Directive and its Annex ;
        Cb ) tests 1 , 2 and 3 listed in item 5.2.4 . show that it con­
              forms with Parts II and III of this Annex as regards
              metrological and technological characteristics ;
        ( c ) after the thermal shock resistance test and after each
              accelerated endurance test , no variation in relation to
              the initial curve greater than 1.5% between                and Q    or
              greater
              3
                       than   3% between      Q   .
                                                mint
                                                     and  Q. has been  observed .
        The EEC pattern approval certificate may lay down rules of
        equivalence enabling initial verification to be carried out
        with cold water .
 ---pagebreak---                                   - 12-
EEC INITIAL VERIFICATION .
6.1 .  Verification methods .
       EEC initial verification will be carried out in a place approved
       by the metrological service of the Member State .
       The layout of the premises and the test equipment should be such
       that verification may be carried out in safe , reliable condi­
       tions , and with no loss of time for the person responsible for
       the control . The provisions of item 5.2.3 . must be complied
       with , except with respect to temperatures in the event of the
       tests being carried out with cold water in accordance with such
       provisions as may be laid down in the EEC pattern approval
       certificate . Arrangements may be made at the test centre to
       enable the meters to be tested in series . The exit pressure
       of all the meters should always be sufficient to prevent
       cavitation and special measures may be required to prevent
       interference between meters .
                             f
       The complete unit may include automatic devices , by-pass valves ,
       f low-restri ctors , etc ., provided that each test circuit between
       the meters to be verified and the control tanks is clearly
       defined and that it is possible to verify at any time its
       internal pressure absorption .
       Any type of water supply system may be used , but if several
       test circuits are operated in parallel , there should be no
       interference incompatible with the provisions of item 5.2.3 .
       If a control tank is divided into several     chambers , the sepa­
       rating walls should be sufficiently rigid     to ensure that the
       volume of a chamber does not vary by more     than 0.2% according
       to whether the adjacent chambers are full     or empty .
6.2 .  Inspection operations .
       The meters must conform to an approved pattern .
       Conformity with this pattern may be verified by a random
       sample inspection of the various components during manufacture
       and assembly or by opening one of the meters submitted .
       Verification includes a leak-tightness test , which may carried
       out with cold water , and an accuracy test normally conducted
       with hot water at a temperature of 50°C (+ 50°C ) at at least
       three flowrates :
       ( a ) between 0.9 Q max and Q max ;
       ( b ) between     and 1.1 Q^;
       ( c ) between Q .   and 1.1 Q . .
                      min             min
 ---pagebreak---                                                - 13-
 Where the EEC pattern approval certificate permits , initial verification
 of a hot-water meter may be carried out with cold water in accordance with
 the procedures laid down in the certificate .
More specifically , the latter may increase , reduce and/ or re-set the maxi­
mum permissible errors to allow for the effect of the temperature and
pressure of the water on the measured results .             For the same reason , it may ,
for the purpose of the initial verification tests , specify different values
     Hi I Ft
             ® +-L anc' ill a X f rom those laid down for the metering of hot water .
During the leak-tightness test , carried out for one minute at 1.6 times
the maximum operating pressure , there must be no leakage or seepage
through the walls of the meters .
If the accuracy tests consist in comparing the meter indicator reading
against that of the reference standard , the volume of water passed through
the meter in each test should be sufficient to rotate the pointer or roller
on the verification scale through a complete series of revolutions and
should be such that periodic errors are negligible . Any other inspection
procedure may be used , on condition that it is provided for in the pattern
approval certificate and gives an accuracy of measurement at least equiva­
lent to that assured by the foregoing rule .
The first of the accuracy tests involves the determination of pressure loss ,
which should be less than the value indicated in the EEC pattern approval
certificate .
The maximum permissible errors are as shown in item 2.1 .
If all the errors are found to lie in one direction , the water meter shall
be adjusted so that not all the errors exceed one-half of the maximum
permissible error , insofar as the EEC pattern approval certificate does not
lay down special provisions on the subject .