IS 14439-1 (1997): Legal metrology - Gas volume …IS 14439(Part 1): 1997 particular standard without the changes in its metrological properties exceedingthe limits freed bythese requirements.

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IS 14439-1 (1997): Legal metrology - Gas volume meters,Part 1: General requirements [PGD 26: Weights and Measures]

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Indian Standard

LEGAL METROLOGY — GAS VOLUMEMETERS

PART 1 GENERALREQUIREMENTS

ICS 17.120.10

@BIS 1997

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

October 1997 Price Group 7

-.I i“”+

“

//

Commercial Weights and Measures Sectional Committee, LM 06

FOREWORD

This Indian Standard (Part 1)wasadopted by the Bureau of Indian Standards, after the draft finalizedbythe CommercialWeightsand MeasuresSectional Committee had been approved bythe Light MechanicalEngineering Division Council.

Thisstandard prescribes the general requirements applicable to all types of gasvolume meters includingelectronicgas meters. The additional requirements, specificto a particular type of gasvolume meter, arebeing specifiedin separate standards coveringparticular type of gasvolume meter.

The standard includes the terminology and definitions applicable to the gasvolume meters. It also coversthe provisions relating to location of verification and protection marks to detect/prevent any temperingand the provisions relating to pattern approval for metrological control.

Thecontents of this standard havebeen alignedwith OIMLRecommendation, OIML R 6:1989 ‘Generalprovisionsfor gasvolume meters’ issued by the International Organization of Legal Metrology, France.

The standard on gasvolume meters is currently being published in 3 parts as follows:

Part 1 General requirements,

Part 2 Diaphragm gas meters, and

Part 3 Rotary piston and turbine gas meters.

It is intended to bring-out Part 4 of this standard in due course to cover the particular requirements forElectronic Gas Meters.

For the purpose of decidingwhether a particular requirement of this standard is complied with, the finalvalue,observedor calculated,expressingthe result of a test or analysis,shall be rcmndedoff in accordancewith IS 2: 1960 ‘Rules for rounding off numerical values (revised)’. The number of significant placesretained in the rounded offvalue should be the same as that of the specifiedvalue in this standard.

.

.

IS 14439 (Part 1) :1997

Indian Standard

LEGAL METROLOGY — GAS VOLUMEMETERS

PART 1 GENERALREQUIREMENTS

1 SCOPE

This standard specifies the terminology, andgeneral requirements applicable to gas volumemeters.

2 REFERENCES

The followingIndian Standards contain provisionswhich through reference in this text, constituteprovision of this standard. At the time ofpublication, the editions indicated were valid. Allstandards are subject to revision, and parties toagreements based on this standard are encouragedto investigate the possibility of applying the mostrecent editions of the standards indicated below

IS No. Title

9000 Basic environmental testingprocedures for electronic andelectrical items:

(Part 2/See3): Cold test, Section 3 Cold test for1977 non-heat dissipating items with

gradual change of temperature(Part 3/See5): Dry heat test, Section 5 Dry heat1977 test for heat dissipating itemswith

gradual change of temperature(Part 5/See2): Damp heat (cyclic)test, Section 21981 12+ 12h cyclic(Part 7/See3): Impact test, Section 3 Drop and1979

(Part 8): 19819001

(Part 2):1977(Part 4):1979

toppleVibration (sinusoidal) test

Guidance for environmentaltesting

Cold and dry heat tests

Damp heat test

NOTE — Referenee has also been made to certain IECpublications where the Indian Standardado not existon thesubjects at present.

3 TERMINOLOGY

For the purpose of thisdefinitions shall apply.

standard, the following

3.1 Working Range of a Gas Volume Meter

The range of the flow rates of gas limited by themaximum flow rate Qrnaxand the minimum flowrate Qrnin.

3.2 CyclicVolume of a Gas Volume Meter (P’)

The volume of gas corresponding to the workingcycle of the gas volume meter, that is to all themovements of the moving components which,except for the indicating device and theintermediate transmissions, resume for the firsttime the position they occupied at the beginning ofthe cycle.Thisvolume is determined bymultiplying the valueof the volume corresponding to one completerevolution of the test element, or the value of thesmallest scale interval, by the transmission ratio ofthe measuring deviceto the indicating device.

3.3 Test Element

A device to enable precise reading of the gasvolume.

3.4 Metering Conditions and Base Conditions

3.4.1 Metering Conditions

Conditions of the gas, volume of which is to bemeasured, at the point of measurement (examples:temperature and pressure of the measured gas).

3.4.2 Base Conditions

Conditions to which the measured volume of gas isconverted (examples: base temperature and basepressure).

NOTE —Meteringand baseconditions relate to the volumeof gas to be measured or indicated onty and should not beeonfuaedwith ‘rated operating conditions’ and ‘refereneeconditions’, whichrefer to influeneequantities.

3.5 Conversion Device

A device which converts the volume measured atthe metering conditions to a volume at baseconditions.

-,

IS 14439 (Part 1) :1997

The type of conversion maya) temperature only,b) temperature and pressure, andc) temperature and pressure with cmrection

for deviations from the ideal gas law.

3.6 Working Pressure

The differencebetween the amolutepressure of thegas to be measured at the inlet of the gas volumemeter and at the atmospheric pressure.

3.7 Pressure Absorption

The difference between the pressures at the inletand outlet of the gas volume meter while the gas isflowing.

NOTE — In some gasvolume metem the pressure rccovetyis not complete at the outlet tlange and it maybe necessaryto measure the pressure absorption at a point in thedownstream pipe. Ttds point shall be specified in thestandard particular to that type of gas meter.

3.8 Output Drive Constant

The value of the volume corresponding to onecomplete revolution of the shaft of the outputdriv~ this value is determined by multiplying thevalueof the volume corresponding to one $nmpleterevolution of the test element by the transmissionratio of the indicating device to this shaft.

3.9 Transitional Flowrate (@)

The flowrate at which the maximum permissibleerror changes in value.

3.10 Electronic Gas Meter

A gas meter equipped with electronic devices.NOTE — For the purpose of this standard auxiliatyequipment, as far ap it is subject to metrologicalcontrol, iscmsidered to be part of the gas meter, unless the auxilia~equipment is approved and verified separately.

3.11 Electronic Device

A device employing electronic components andperforming a specific function. Electronic devicesare usually manufactured as separate units and arecapable of being independently tested.

NOTE — An electronic device,as defined above maybe acomplete gaameter or part of a gas meter.

3.12 Error (of Indication)

The indication of a gas meter minus the(conventional) true value of the measurand.

NOTE — Errom (E) are expreaaedin refativevalueaby theratio (expressedas a percentage) of the difference betweenthe indicatedvalue (Vi)and the conventionaltrue value (Vc)of the volume of the teat mediumwhichhas passed throughthe gss meter, to this latter value

n-v.E(%) =loo~

2

3.13 Intrinsic Error

The error of a gas meter used under referenceconditions.

3.14 Initial Intrinsic Error

The intrinsic error of a gas meter as determinedprior to performance test and durabilityevaluations.

3.15 Fault

The differencebetween the error of indication andintrinsic error of a gas meter.

NOTES1 Principallya fault is the result of an undesired change ofdata contained in or flowingthrough an electronicgasmeter.2 From the definition it followsthat a “fault”is a quantitywith a numericalvalue.

3.16 Significant Fault

3.16.1 A fault greater than 0.5 of the maximumpermissible error on initial verification.

3.16.2 The following faults are considered not tobe significant, even if they exceed the significantfault:

a)

b)

faults arising from simultaneous andmutually independent causes in the gasmeter itself or in its checkingfacilities.transitory faults being momentaryvariations in the indication, whichcannot beinterpreted, memorised or transmitted as ameasurement result.

3.17 Durability Error

The difference between the intrinsic error after aperiod of use and the initial intrinsic error of a gasmeter.

3.18 Significant Durability Error

3.18.1 The significant durability error is specifiedin the particular standard.

3.18.2 Durability errors are not relevant, even ifthey exceed the significant durability error, wherethe indications cannot be interpreted, memorizedor transmitted as measurement results.

3.19 Influence Quantity

A quantity which is not the subject of themeasurement but which influences the value of themeasurand or the indication of the gas meter.

3.19.1 Influence Factor

An influence quantity having a value within thenormal operating conditions of the gas meter.

. . . . . ...*.

‘,!

1’1

3.19.2 Disturbance

An influencequantity not being an influencefactor.

3.20 Normal Operating Conditions

Conditions of use, giving the range of values ofinfluence quantities for which the metrologicalcharacteristics are intended to lie within thespecified maximum permissible errors.

3.21 Reference Conditions

A set of specified values of influence factors f~edto ensure valid intercomparison of results ofmeasurements.

3.22 Performance

The ability of the gas meter to accomplish theintended functions.

3.23 Durability

The ability of the gas meter to maintain itsperformance characteristics over a period of use.

3.24 Checking Facility

A facilitywhich is incorporated in a gas meter andenables significant faults to be detected and actedupon.

NOTE — By ‘acted upon’ is meant any adequate responseby the gas meter.

3,25 Durability Protection Feature

A feature which is incorporated in a gas meter andwhich enables durability errors in excess of thesignificantdurability error to be detected and actedupon.

3.26 Test

A series of operations intended to verify thecompliance of the equipment under test (EUT)with certain requirethents.

3,26.1 Test Procedure

A detailed description of the test operations.

3.26.2 Test Programme

A description of a series of tests for a certain typeof equipment.

IS 14439 (Part 1) :1997

4 GENERALREQUIREMENTSFOR GASVOLUMEMETERS

4.1 Field ofApplication

These requirements apply to the followingtypes ofgasvolume maters:

a) Positive displacement gas meters(volumetric gas meters): diaphragm gasmeters, rotary piston gas meters.

b) Inferential gas meters: turbine gas meters.NOTE — In this standard gasvolumemeters are referred toas ‘gasmeted.

4.2 Construction

4.2.1 General

Gas meters shall be designed and manufactured insuch a way that they do not exceed maximumpermissible errors under normal operatingconditions of temperature as specified in 10.2(a)and over the ranges of temperature and pressure ofthe measured gas (metering cmditions) as claimedby the manufacturer.

4.2.2 Materials

Gas meters shall be made of sound materialschanginglittle with age and sut%cientlyresistant tocorrosion and to the attacks of the gases for whichthe gas meters are intended to be used and theirpossible condensates.

4.2.3 Soundness of Cases

The easesof gas meters shall be gas-tight up to themaximumworking pressure of the gas meters.Ifmeters are to be installed in the open air theyshallbe impermeable to runoff water.

4.2.4 Protection Against Ertemal Interference

Gas meter shall be constructed in such a way thatany mechanical interference capable of affectingthe measuring accuracy results in permanentlyvisible damage to the gas meter or to theverification mark or protection mark.

4.2.5 Dkection of the Gas F1OW

On gasmeters where the indicating deviceregisterspositivelyfor one direction onlyof the gas flow,thisdirection shall be indicated byan arrow. This arrowis not required if the direction of the gas flow isdetermined by the ecmstruction.

3.26,3 Pe~ormance Test A protective deviee may also be provided whichwould prevent the functioning of the gas meter

A test to verify whether the EUT is able to when the gasflowis in the direction opposite to thataccomplish its intended functions. intended for measuring.

3.26.4 Durability Test 4.2.6 Metrolo@cal Properties

A test to veri~ whether the EUTis able to maintain At a f!owrate equal to ‘Q~~’a gas meter shall beits performance characteristics overa period ofuse. able to function continuously for a time freedby the

3

.1,’

IS 14439 (Part 1): 1997

particular standard without the changes in itsmetrological properties exceedingthe limits freedby these requirements.

4.3 Additional Devices

4.3.1 Gas meters maybe fitted with:a) prepayment devices,b) integral pulse generators, the outlets of

which shall bear an indication of the valueof one pulse in the form:‘1im

#= ... m3 (or dm3)’ or

‘1m = ... imp.’,c) a built-in conversion device,andd) a built-in self-checking and possibly self-

adjusting device.

These devicesare regarded as forming an integralpart of the gasmete~ they shall havebeen installedin the gasmeter at the time of pattern approval andinitial verification.

4.3.2 Gas meters may be fitted with output driveshaftswhich should be taken to include drive shaftsor other facilities for operating detachableadditional devices.The torque whichthe gasmetersare required to produce in order to drive theadditional devices fitted shall not produce anychangesin the gasmeter indication greater than thespecifiedvalues.

4.3.2.1 If there is only one drive shaft, it shall becharacterized bywt indication of its constant (C)inthe form”1 Rev. = ... m3(or dm~”, of the maximumpermissible torque in the form “Mm= ...N.mm”.and of the direction of rotation.

4.3.2.2 If there are several drive shatl.s,each shaftshall be characterized by the letter ‘M’ withsubscript in the form “Ml,Mz... Mn”,as well as byan indication of its constant in the form”1 rev. = ...m3 (or dm3)”and of the direction of rotation.The following formula shall appear on the gasmeter, preferably on the data plate

klMl+k2Mz+ ..........+k&. s A AJ.mm

where

‘A’ is the numerical value of the maximumpermissible torque applied to the drive shaft withthe highest constant, where the torque is appliedonly to this shafi, this shaft shall be characterizedby the symbolMI,

ki (i = 1,2, ...n) is a numerical value determined asfollows:

Li

Mi (i = 1,2, ...n) represents the torque applied tothe drive shaft characterized by the ‘symbol.Mi,

4

Ci (i = 1, 2, ...n) represents the constant for thedrive shaft characterized by the symbolML

4.3.2.3 When not connected to an attachableadditional device, the exposed ends of the driveshafts shall be suitably protected.

4.3.2.4 The cxxtnection between the measuringdevice and the intermediate gearing shall notbe broken or altered, if a torque .of three timesthe permissible torque as indicated in 4.3.2.1and4.3.2.2is applied.

5 MARKINGS

5.1 Each gas meter shall bear, either on, the faceplate, or on a special data plat~ the followingmarkings:

a)

b)c)

d)

e)

f)

g)

h)

j)

k)

he pattern approval sign of the gas meter,if appropriate,The manufacturer’s identification markThe serial number of the gas meter and itsyear of manufacture,The designation of the gasmetev this desig-nation is in the form of the capital letter ‘G’,followedbya number fixedin the particularstandard,The maximumflowrate ~- = ... m3/h,The minimum flowrate Q* = ...m3/h(ordm3/h)The ~aximum working pressure Pm= =kgkxn (or gtn/cm2),For volumetric gas meters, the nominalvalue of the cyclicvolume V = ... m3 (ordm~,The range of the metering coriditions inwhich the gas meter is required to workwithin the specified maximum permissibleerrors, expressedas:

tnl = .4.-... “C,Pm= ...- ...kg/cm2(or gmkrn~,

Ifrequira a commercialdesignation of thegasmeter, a special serial number, the nameof the gas distributor, the name of therepairt?rahd the year of repair.

These markings shall be directly visible, easilylegiile and indeliile under normal conditions ofuse of the gas meters.

!5.2The particular standard may prescribe othermarkings, such as the nature of the gas to bemeasured

5.3 Without special authorization, the use of anymarking other than those prescrii in the patternapproval document, unless required by othernational regulations, is prohibited.

,,

6 INDICATINGDEVICESANDTESTELEMENT

6.1 Indicating Device

6.LI General Requirements

6.L1.1 Gas meters shall be equipped with anindicating deviee directly indicating the volume ofgas measured.

The indicating deviee shall indicate the volume ofthe measured gas in cubic meters. llte symbol ‘m3’shall appear on the face plate.

The scale intetval shall not exceed ‘1 m3’or thevolume passed during one hour at Qtnin,whicheveris the greater.

6.1.1.2 The indicating device maybea) a mechanical indicating device as meant in

6.1.2,b) an electromechanical or electronic in-

dicating deviceas meant in 6.1.3, andc) a combinatiomof ( a) and,@).

6.1.1.3 The indicating deviee shall correspond toone of the followingpossibilities:

a)

b)

The gas meter has one indicating devieedisplaying the volume at metering con-ditions. The symbol‘r& shall appear on theface plate,The gas meter has two indicating devices,one displaying the volume at metering con-ditions, the other displaying the volume atbase conditions. The symbol ‘m~ shall appear on the face plate, accompanied by thespecification of those base conditions, ex-pressed as:m = ..: C (or “K),Pb = ... kg/em2(or gntktn~.

It shall be clear and unambiguous as to whichof theindicating devices these markings relate.

NOTESI The valuea chosen for base conditiom shatl preferablybe: WC,15°CorWCand0.0102 kg/em2.

2 One displaymaybe used for both indicatioxw

c) A diaphragm gas meter with a built-intemperature eonversion deviee may haveonly one indicating deviee displaying thevolume at base conditions. The symbol ‘m%shall appear on the faceplate, accompaniedbythe specification of the base temperature,expressed as:

h = ...”CNOTE — The VdUeS chosen for base temperature ahattpreferably be tY’~15°Cor WC

6.1.1.4 The indicating deviee shall be so designedthat the reading is by simple juxtaposition.

IS 14439 (F’art1) :1997

6.1.2 Mechanical Indicating Device

6.1.2.1 A mechanical indicating device shallconsist of drums; the last element (that is, the onewith the smallest scale interval) mayhoweverbeanexeeption to this rule.

NOTE — It appears that in certain designs, the mandato~use of drums in mtAattical indkating devices cauaea, atpresent, great inconvenience.Inconsequence, these deaignaare, pti]onalfy, in need of requirements for indkatingdevices with pointem. It is recommended that for thispurpose they apply to the requirements in AnnexA.

6.1.2.2 Where the indicating device includesdrums showing deeimal submultiple of the cubicmetre, these drums shall be separated by a cleardecimal signfrom those showingettbicmetres. Thedecades after the deeimal sign shall be clearlydistinguished from those in front of the decimalsign.

6.1.2.3 Where the last drum shows a decimalmultiple of the cubicmetrt$the faceplate shallbtxm

a) either one (or two, or three, etc) fixedzero(s) after the last drum,

b) or the marking’ X 10’ (or’ X 100’,or’ XI@O’,etc), so that the reading is always incubic metrea.

6.12.4 A mechanical indicating device shall haveat least a sufficient number of drums to ensure thatthe volume pw+?dduritig2000 hours at maximumflowrate does not return all the drums to theirinitial positions.

6.12S The diameter of the drums shall be at least16mm.

6.1.2.6 The advance by one unit of a figure of anyorder shall take place completely while the figureof an order immediately below passes through thelast tenth of its eottrse.

6.1.2.7 A mecltanieal indicating device shall beeasily removable if such removal is necessary forverification.

6.1.3 Electromechanical or Electronic IndicatingLkvice

6.1.3.1 Electromeehanierd or electronic indicatingdevices shall be nonresettable and shall benonvolatile (that is, it must be able to show the lastcorrect indication after the deviee has recoveredfrom an intervening power failure).

6.132 The provisions of 6.1.2.2, 6.1.2.3and 6.1.2.4 are also applicable to electro-mechanical and electronic indicating devices.

5

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1S 14439 (Part 1) :1997

6.2 Test Element

6.2.1 General Requirements

6.2.1.1 Gas meters shall be designed in such a waythat they maybe verifiedwith sufficientaccuracyina reasonablyshort time. For this purpose theyshallbe constructed either with an integral test elementor with arrangements permitting the connection ofa portable test unit.

6.2.1.2 If a gas meter has two indicating devicesaspermitted in 6.1.1.3(b), each indicating deviceshallhave a test element, in order to verify theperformance of the conversion device withsufficient accuracyin a reasonably short time.

6.2.2 Test Element of a Mechanical IndicatingDevice

6.2.2.1 The integral test element mayconsist of thelast element of the mechanical indicating deviceinone of the two following forms:

a) A continuously moving drum bearing ascale,

b) A pointer moving over a fwed dial with ascale, or a disk with a scale moving past afixed reference mark. The diameter of thegraduated scale shall at least be 16mm.

6.2.2.2 On the numbered scale of a test elementreferred to in 6.2.2.l(b) the value of one completerevolution of the pointer shall be indicated in theform:’1 rev. = ... m3(or dm~’. The beginning of thescale shall be indicated by the figure zero.

6.2.2.3 The scale spacing shall not be leas than‘1mm’and shall be constant throughout the wholescale.

6.2.2.4 The scale interval must be in the form‘1x 10n’,‘2x 10n’,or ‘5x 10nm3’(n being a positiveor negative whole number or zero).

6.2.2.5 The scale marks shall be fine and uniformlydrawn.

In the case where scale interval is in the form‘1 x 10R’,or’2 x 10nm3’all the lines representingmultiples of 5, and where the scale interval is in theform ‘5 x 10n mx all the lines representingmultiples of 2, shall be distinguished by beinglonger than the other lines. The scale marks shallbe sufficiently thin to permit accurate and easyreading.

6.2.2.6 The test element may be provided with ascalemark which stands out in contrast to the scaleand is of sufficient size to allow automaticphotoelectric scanning. This scale mark shall notobscure the graduation and its presence shall notbe detrimental to the accuracyof reading,

6.2.3 Pulse Generator Used as Test Element

6.2.3.1 A pulse generator maybe used as atest element if it complies with therequirements of 6.2.3.2 to 6.2.3.6.

6.2.3.2 The value of one pulse, expressed in unitsof volume, shall be marked on the gas meter. Thisvalue shall comprise at least 6 significant figures,unless it is equal to an integer multiple or decimalfraction of the unit of volume indicated on the faceplate of the indicating device.

6.2.3.3 The pulsevalue shall be calculated from thetransmission ratio between the indication of the gasmeter and the location where the pulses aregenerated.

The manufacturer shall, at verification, submitdocumentation by which the calculation of thepulse value can be checked.

6.2.3.4 The gas meter shall be constructed in sucha way that, prior to initial verification, thecalculated pulse value w specified can be checkedexperimentallywith an uncertainty not greater than0.05percent.

6.2.3.5 If a removable pulse generator is used, itshall be possible to attach and remove this pulsegenerator easily.

If the gas meter needs to supply a torque to drivethe removable pulse generator, this torque shallhave a negligible influence on the performance ofthe gas meter. The removable pulse generator isconsidered to comply with this requirement if theinfluence is less than 0.1 percent at a flowrateequalto 0.1 Qmax.

6.2.3.6 Measures shall be taken to prevent thecyclicvolume of the gas meter having an influenceon the accuracyof the verification.

NOTE — This can be accomplished by counting a numberofputaea that match an integer multiple of the cyclicvolume,or bymeasuringavolumetargeenoughto makethe influencenegligible.

7 MAXIMUMPERMISSIBLE ERRORS

7.1 The values of the maximum permissible errorsare f~ed in the particular standard. They are validfor the authorized direction of flow.

7.2 If the gasmeter has two indicating devices,onereading the volume at metering conditions and theother the volume at base conditions, the values ofthe maximum permissible errors apply to theindicating device for the volume at meteringconditions. The difference in the errors ofindication de~erminedfrom both indicating devices

6

shall not be more than the value stxxitled in thefollowing table

TyF of Conversion

a) Temperatureb) Temperature and

pressurec) Temperature and

pressure and idealeas lawdeviations

1

hi arimurn Diff2renee in Error (%)

On initialverification

eonditiona

I

Ref Non Ref

0.5 1.00.s 1.3

1.0 1.5

In aefice

conditions

Ref

0.71.2

1.5

Non Ref

1.51.9

2.2

The referenceconditions asspecifiedin 10.2(a) areapplicable. Non reference conditions are normaloperating conditions as specifiedin 10.2(a), otherthan reference conditions.

NOTES

lIt maybe possibleto use one displayfor both indieationa.21n-servieevalues are recommendedvalues.

7.3 For a gas meter as meant in 6.1.1.3(c) theconventional true value at the meteringtemperature shall be converted to the volume atbase temperature. The particular standard mayspecifylarger maximum permissible errors for thetype of gas meter covered in that particularstandard.

8 PRESSURE ABSORPTION

The maximum permissible values of pressureabsorption may be fixed if appropriate, by theparticular standard.

9 LOCATIONOF VERIFICATIONANDPROTECTION MARKS

9.1 General Provision

The location of the marks shall be chosen in such away that the dismantling of the part sealed by oneof these marks results in permanently visibledamage to this mark.

9.2 Data Plate

Gas meters shall have a special location forapplying the verification mar~ removal of the dataplate shall result in permanently visible damage tothis mark.

9.3 Other Locations

Locations forverification or protection marks shallbe provided on everygas meter:

a)

b)

on all plates which bear informationprescribed by this standard and/or by theparticular standard,on all parts of the case which cannot beotherwise protected against interference

7

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c)

IS 14439(Part 1): 1997

likelyto affect the accuracyof the measure-ment.on the connection with the detachable addi-tional devicesreferred to in 4.3.2.3.

10 PROVISIONS FOR ELECTRONIC GASVOLUMEMETERS

It specifiesthe general, technical and metrologicalrequirements for electronic gas meters, as they areflefinedin this standard, in viewof the applicationof electronics.

10.1 Application Conditions for Electronic GasMeters

10.LI CfassiJcatwn for Environmental ConditionsGas meters are classified according to theirintended use under various environmentalconditions, into the followingclasses.

Class B : This class applies, to enclosedlocations, having only low levelsof vibration and shock.

class c : This classapplies to locations havinga general open air climate and onlylow levels of vibration and shock

Class F : This classapplies to locations havinga general open air climate andmedium levels of vibration andshock.

10.2 Influence Factors

a) Temperaturei) Normal operating conditions: ClassB:

between - 1(PCto + 40”Cii) Class=’C and F: between – 25°Cto +

55*Ciii) Reference conditiotx a value between

15°Cto 25°Cb) Relative humidity

i) Normal operating conditions: s 93percent

ii) Reference conditions: a value be-twqen 40 to 60 percent

c) Variations in the mains power supplyi) Normal operating conditions: the

specifiedseverity level (seeAnnex B)ii) Reference conditions: no variation

d) External magnetic tielcki) Normal operating conditions: test

conditions specified in 12.5.3ii) Referenm condition:the absence of

external magnetic fields.

10.3 Disturbances

a) Vibration (Class F only),

IS 14439 (Part 1): 1997

b) Shock (Class F only),.c) Power interruptions,d) Bursts,e) Electrostatic discharge, andf) Electromagnetic interference.

Operating conditions:the specified severity levels(see Annex B)

Reference conditions: the absence of thedisturbance.

10.4 Battery Power Supply

Gas meters which operate from a battery or otherpower source which must periodically be replacedshall indicate the need for replacement, at least 90days before power Mlure. Replacement of thepower source shall not adversely affect theprogramming, metering information, orsubsequent operation of the gas meter.

11 REQUIREMENTS FOR ELECTRONIC GASMETERS

Electronic gas meters shall comply with thefollowing requirements, notwithstanding all othertechnical and metrological requirements:

11.1 General Requirements

11.1.1 Electronic gas meters shall be designed andmanufactured in such a waythat they do not exceedmaximum permissible errors under normaloperating conditions.

11.1.2 Electronic gas meters shall be designed andmanufactured in such a way that, when they areexposed to disturbances, significant faults do notoccur.

NOTES

lAkult~ti Ww~tititiw=~tti Al&lis allowed irrespectively of the value of the error ofindication.

2Thii requirement does not prohibit the uae of eheekingExilities.

11.L3 The provisions of 11.1.1and 11.1.2shall bemet durably. Electronic gas meters shall bedesigned and manufactured in such a waythat

eitheca) the signitkmtt durability error is not ex-

ceeded, orb) a durability error ex&@ng the significant

durability error is detected and acted uponby means of a durability protection feature.

11.1.4 The pattern of a gas meter is presumed tocomply with the requirements stated in 11.1.1,11.1.2 and 11.1S if it passes the examination andtests specifiedin 12.5and in the particular standard.

11.1.5 The choice,whether 11.13(a) or 11.13 (b)is applied, is left to the manufacturer.

8

11.2 Requirements for electronic gas meters fittedwith durabHity protection features

11.2.1 It shallbe possible toveri@’the presence andcorrect functioning of these features.

NOTE — Tbia veritieationmaybeaccomprihedbymeansofatest buttonorbyanyothermeana.

11.2.2 The requirement of 11.2.1does not apply togas meters or parta of gas meters for which themanufacturer claims that they comply with therequirementsof 1LL3(a)andwhichareneverthelessequipped with durability protection features.

12 METROLOGICALCONTROL

As the gas meters are subject to state metrologicalcontrols, it is recommended that they include all orsome,of the followingcontrols.

12.1 Pattekn Approval

12.1.1 Each pattern of a gas meter from eachmanufacturer is subject to the pattern approvalprocedure.

12.1.2 Without special authorization, nomodification maybe made to an approved pattern.

12.1S Applications for pattern approval for gasmetetx shall be accompanied by the followingdocuments

—

—

—

—

——

—

.

—

—

—

—

—

a description of the meter giving the technicalcharacteristic and the principle of its opera-tio~a perspective drawing or photograph of themeter,a nomenclature of parts with a description ofconstituent materials of such’parts,an assemblydrawingwith identification of thecomponent parts listed in the nomenclature,a dimensioned drawinga drawing showing the location of verificationmarks and seals,a drawing of the indicating devicewith adjust-ment mechanisms,a diinensioned drawing of metrologically im-Pc@antcomponents,a drawingof the data plate ‘orfaceplate and ofthe arrangements for inscriptions,where appropriat~ a drawingof the additionaldevices,where appropriate a table setting out the char-acteristic of the drive shafts,where appropriat~ a list of electronic com-ponents with their essential characteristics,where appropriate; a description of theelectronic devhx=$with drawin~, diagrams

-... ,“ ‘3>.;

—

——

and general softwareexplainingtheir cmstruc-tion and operation,where appropriat~ the application for patternapproval shall be accompanied by any docu-ment or other evidence which supports theassumption that the designand construction ofthe electronic gas meter comply with the re-quirements,NOTE — Safetyrequirements are to be respected.a list of the documents submitted, anda declaration specifying that the metersmanufactured in conformity with the patternmeet the requirements for safety, particularlythose concerning the maximumworking pres-sure as indicated on the data plates.

12.1.4 The following particulars shall appear onthe pattern approval certificate

—

—

—

———

.—

—

the name and address of the person to whomthe pattern approval certificate is issued,the type of the gas meter and/or commercialdesignation,the principal technical and metrologicalcharacteristics, such as the minimum flow,maximum working pressure, nominal inter-nal diameter of the connecting pieces and, inthe case of volumetric gas meters : thenominal value of the cyclicvolume,the pattern approval sign,the period of validity of the pattern approval,for meters equipped with drive shafts:

a) the characteristics of the shaft as set out in4.3.2.1(where there is only one drive shaft),

b) the characteristics of each shaft and theformula given in 4.3.2.2 (where there aretwo or more drive shafts),

the environmental classification,information on the location of the pattern ap-proval sign, initial verification marks and seals(where appropriate, in the form ofphotographs or drawings),a list of the documents accompanyingthe pat-tern approval certificate, and - - - -any speeial comments.

12.L5 Tests for Electronic Gas Meters

Electronic gas meters shall be subjected to thefollowing examinations and tests:

a) examination to verifywhether the gasmetercomplies with the requirements of 11.1.

b) performance tests to verifycompliancewiththe requirements of 11.1.1, regarding in-fluence factors, and 11.1.2,regarding distur-bances. During these tests the EUTshallbein an operational state (that is, the powershall be switched on).

c)

d)

IS 14439 (Part 1): 1997

durability evaluation (that is, tests and/orother measures) to verify compliance withthe requirements of 11.1.3.examination and test to verify where ap-plicablethe complianceof theelectronicgasmeter with the requirements of 11.1.3and11.1.4.

All gas meters, whether or not equipped withchecking facilities and whether or not equippedwith durability protection features, are subject tothe same test-programme.

12.L5.I Perjiormance tests (carried out prior todurability testi)

During these tests the gas meter shall complywith:— the requirements of 11.1.1, the maximum

permissibleerror and being the maximumper-missible error on initial verification,

— the requirements of 11.1.2.

12.1.5.2 Durability programme

During performance tests carried out after eachdurability test the gas meter shall comply withrequirements of 11.1.

12.1.5.3 Testpe@ormance

The followingtests shall be performedInfluence factors:

a)

b)

c)

d)

e)

Static temperatures, dry heatSeeAnnex B, B-1,Severitylevel: ClassB: severitylevel 1Clas-ses C and F: severity level 2Static temperature+ cold:SeeAnnex B, B-2,Severitylevel: Class B: severity level 1Classes C and F: severity level 2Damp heat, cyclic:SeeAnnex B, B-3Severity level : Class B : severity level 1Classes C and F: severity level 2Mains power supply variations:See Annex B, B-4, severity level 1External magnetic fields:Electronic gas meters shall be subject totests in any orientation within a 50 Hz(60 Hz) alternating magnetic fieldequivalent to that produced by a circularcoil, one meter in diameter having 400Ampere turns.

Disturbances:a) Vibration (Class F only):

SeeAnnex B, B-5severity level 1b) Shock (Class F only):

SeeAnnex B, B-6, severity level 1c) Short time power reduction:

SeeAnnex B, B-7, severity level 1

9

KS 14439 (Part 1) :1997

d) Electrical bursts: included in a simulated measurement set-up,See Annex B, B-8, severity level 1 sufficiently representative for its normal operation.

e) Electrostatic discharge. NOTE — It is not intended that the gasmeters or devieesbeSee Annex B, B-9,severitylevel 1 dismantledfor the tests.

f) Electromagnetic suseeptibili~See Annex B, B-10, severity level 1 13 INITIAL VERIFICATION

12.L5.4 Testprocedures

The test procedures are specified M Annex B.

12.1.5.5 Equipment under test (EUT)

As a rule, tests will be carried out on the completegas meter. If the size or configuration of the gasmeter does not lend itself to testing of the gas meteras a whole unit, or if only a separate deviceof thegasmeter is concerned, the tests shall be carriedouton the electronic devices,provided that, in case oftestswith the devieesin operation, these devieesare

New gas meters are subject to the procedure forinitial .veriikation. They shall comply with therelevant requirements. These requirements applyequally to subsequent verifications of repaired orreadjusted gas meters.

14 SUBSEQUENT VERIFICATIONS

Recommended requirements for subsequentverifications may be given in the particularstandards.

,

10

IS 14439 (Part 1) :1997

ANNEX A

(Clause 6.1.2.1)

INDICATING DEVICES WITH POINTERS

A-1 The face of an indicating devicewith pointersshall have circular scales intended for reading thevolume of measured gas, each graduated into 10divisions of the same length. The scalemarks shallbe numbered successivelyfrom Oto 9, the ‘O”scalemark being at the top of the scale. The diameter ofthe circular scales shall beat least equal to 16mm.The face shall have enough numbered circularscalesto indicate the volume deliveredduring 2000hours working at maximum flowrate.The symbol ‘m3’shall appear on the dial.A-2 The intermediate transmissions of theindicatingdevicewith a pointer shall beso arrangedthat the direction of rotation of the pointers ofcircular scales alternates when one considers thenext circular scale of which the value, in volume,shall be ten times greater or ten times smaller.A-3 The pointer moving at the highest speed shallbe on the right hand side of the indicating de~cewhenviewedbyan observer standing in front of themeter.

The direction of rotation of this pointer shall beclockwise. The value of a complete revolution of

this pointer shall correspond to 10 m3, or 100 m3,or, etc.

A-4 Each numbered circular scale shall indicateclearly and nonambiguously the value, in units ofvolume, corresponding to one complete revolutionof its pointer. The direction of rotation of thepointer shall be indicated by means of an arrow.

A-5 Circular scales not intended to indicate themeasured volume of gas (for example, scalesintended for the verification of the meter or thecontrol of its metrological qualities) areauthorized. However, these scales shall be off thegeometric line on which the circular scalesused forindicating the volumes of measured gasare,aligned.

A circular scalenot intended to indicate the volumeofgasmeasured for use shall carry,within the circle,a clear indication of the value of the volumecorresponding to one complete revolution of thepointer. The scale shall have 10 divisions of thesame length, the scale marks not being numbered.An arrow shall indicate the direction of rotation ofthe pointer.

ANNEX B

(Clauses 10.2,10.3, 12.1.5.3 and 12.L5.4)TESTS FOR ELECTRONIC GASMETERS

B-1 DRY HEAT TEST (NON-CONDENSING)

B-1.l The test consists of exposure to the specifiedhigh temperature under “freeair”condition for thetime specified (The time specified is the time afterthe EUT has reached temperature stability).

B-1.2 The test shall be conducted in accordancewith IS 9001 (Part 2) and IS 9000 (Part 3/See5).

B-1.3 The change of temperature shall not exceed1°C/minduring heating up and cooling down.

B-1.4 The absolute humidity of the testatmosphere shall not exceed20 g/m3.

B-1.5 Prior to the test the ELJTshall be calibratedunder reference conditions. During the test theerror of indication shall be determined severaltimes.

B-1.6 Test Severity

The followingseverities shall apply:

~

B-2 COLD TEST

B-2.1 f’hetest consists of exposure to the specifiedlow temperature under “freeair” condition for thetime specified (The time specified is the time afterthe EUT has reached temperature stability).

B-2.2 The test shall be conducted in accordancewith IS 9001 (Part 2) and IS 9000 (Part 2/See 3).

B-2.3 The change of temperature shall not exceed1°C/minduring heating up and cooling down.

B-2.4 Prior to the test the EUT shall be calibratedunder reference conditions. During the test the

,’

,,

11

. .!, I ‘ ““”r

IS 14439 (part 1) :1997

error of indication shall be determined severaltimes.

B-2.5 Test Severity

The followingseverities shall apply

I Severity 1 21Temperature(”C) -10 -25Duration (hours) 2 2

B-3 DAMP HEAT,CYCLIC

B-3.1 The test consists of exposure to cyclictemperature variation between 25°C and theappropriate upper temperature, maintaining therelative humidity above 95 percent during thetemperature change and low temperature phases,and at 93*3 percent at the upper temperaturephases.

B-3.2 The test shall be conducted in accordancewith’IS 9001 (Part 4) and IS 9000 (Part 5/See2).

B-3.3 Condensation should occur on the EUTduring the temperature rise.

B-3.4 Prior to the test the EUT shall be calibratedunder reference conditions. During the test theerror of indication shall be determined severaltimes.

B-3.5 Test Severity

The followingseverities shall apply

I Severity 1 2

Upper temperature (“C) 40 55Duration (cycles) 2 2

B-4 VARIATIONSIN MAINSPOWER SUPPLY

B-4.1 The test for variation in ac mains powersupply (single phase) consists of exposure, atnormal atmospheric conditions for testing, to thespecified power supply condition for a period longenough to achieve temperature stability and toperform the required measurements.

B-4.2 Test Severity

The following severity shall apply

[ Severity 1

Mains voltage(V) upper limit V(nom) + 10%lower limit V(nom) - 15%

Mains frequenq upper limit f(nom) +2%(Hz) lower limit f(nom) -2%

NOT17 — For a three-phase power supply the voltagevariation shatfappfyto each phase successively.

B-5(t@ VIBRATION (RANDOM)

B-5(a).l The test consists of exposure to vibrationfor a time long enough to test the various functions

of the EUT during the exposure. The EUT shall betested in t~ree mutually perpendicular axesin turn,mounted on a rigid fixture by its normal mountingmeans.

The EUT shall normally be mounted so that thegravitational force acts in the same direction as itwould when the instrument is in use. Where theeffect of gravitational force k not important theEUT ma~be mounted in any attitude. ”

B-5(a).2 Test Severity

The followingseverityshall apply

Severity 1

Total frequencyrange Hz)-$ ,6

10-150Total RMS level (m.sASD level, 10-20Hz (m .s-3) 0:048ASD level,20-150Hz (dB/octave) –3Number of axea 3Duration per axis Minimum 2 minutes in each

functional modeNOTE — For teat detaits reference maybe made to IECpublication6S-2-36,first e&ion, 1973,Basicenvironmentaltestingprocedures,Part Z Teat, teat Fdb: Random vibrationrepruducabWy wide band — medium,as there is no fndmnStancfmt availabk?on the subject at present.

B.5(b) VIBRATION (SINUSOIDAL)

(As an alternative to the random viiration test)

B-(b).l The te$t shall be conducted in accordancewith IS 9000 (Part 8).

B-5(t3).2 Test procedure

The EUT shall be tested bysweepingthe frequencyin the specified frequency range, at 1 octave/minute, at the specified acceleration level with aspecified number of sweep cycles per axis. TheEUT shall be tested in its three, mutuallyperpendicular,mainaxes,mountedon a rigid fixturebyitanormrdmeans. It shallnormallybemourtted sothat the gravitationalfirm actsin the samedirectionas it wouldwhen the instrument is in use. Where theeffect of gmvitational forti is not important, theEUT maybe mounted in any attitude:

B-5(b).3 TEST SEVERITY

The followingseverityshall apply

I Severity 1

Frequency range (Hz) 10-150Mux acceleration level (rft/s2) 2Number of sweep cyclesper axis20

B-6 MECHANICALSHOCK

B-6.1 Test Procedure

The test shall be conducted in accordance withIS 9000 (Part 7/See 3). The EUT, standing in its

12

normal position of use on a rigid surface, shall betilted about one bottom edge and then allowed tofall freelyonto the test surface. All coversshall beproperly fitted.

B-6.2 Test Severity

The followingseverityshall apply

Severity 1

Height of fall (mm) 25Number of falls (for each bottom edge) 2

NOTE — Height of till meansd~tance betweenthe elevatededge and the test surtke. However,the angle made by thebottom and the teat surface shall not exceedW.

B-7 SHORT-TIME POWER REDUCTION

B-7.1 The test is carried out to determine theeffectof short-time interruptions and reductions inmains voltage.

B-7.2 Test Procedure

A test generator suitable to reduce the amplitudeof one or more half cycles(at zero crossings)of theac mains voltage is used. The test generator shallbe adjusted before connecting the EUT. Themainsvoltage interruptions and reductions shall berepeated ten times with an interval of at least 10seconds.

B-7.3 Test Severity

The following severities shall apply:

Severity la lb

Reduction 100 % 50%Number of half cycles 5 10

B-8 ELECTRICALBURSTS

B-8.1Test Procedure

The test consists of exposure to bursts of doubleexponential waveform transient voltages. Eachspike shall have a rise time of 5 ns and ahalf-amplitude duration of 50 ns.The burst length shall be 15 ma, the burstperiod(repetition time interval) shall be 300 ms. Theburst generator shall have an output impedance of50 ohms and shall be adjusted before connectingthe EUT. Bursts shall be coupled to the EUT bothin common mode and differential modeinterference. At ieast 10 positive and 10 negativerandomly phased bursts shall be applied in eachmode. Insertion of blocking filters in the cables tothe EUT may be necessary to prevent the burstenergy being dissipated in the mains or in otherinterconnected units.

B-8.2 Peak Value Amplitude

The peak value amplitude used for the test shall be0.5 kV.

IS 14439 (Part 1) :1997

NOTE — For fulltest details refe~nce maybe made to IECpublicationS01-4(19S4)Electromagnetic compatibilityforindustrial-proeeas measurement and control equipment,Part 4: Electricalfast transienmumt requirements, as thereis no Indian Standard availableon the subject at present.

B-9 ELEC1’ROSTA~C DISCHARGE

B-9.1 Test Procedure

A capacitor of 150pF shall be chargedbya suitableDC voltage source. The capacitor shall be thendischarged through the EUT by connecting oneterminal to ground (chassis) and the other via 150ohms to surfaces which are normally accessible tothe operator.

B-9.1.1 At least 10dischargesshallbe applied. Thetime interval betweensuccessivedischargesshall beat least ten seconds.

B-9.1.2 An EUT without a ground (earth)terminal shall be placed on a grounded plate whichprojects beyond the EUT by at least 0.1 m on allsides.The ground connection to the capacitor shallbe as short as possible.

B-9.1.3 The dischargeelectrode shall approach theEUT until discharge occurs, and shall then bewithdrawn before the next discharge.

B-9.2 Test Severity

The followingseverityshall apply

Severity 1

DC voltage (kV) up to and including 8NOTE— For fufftest detaits reference maybe made to @CPublicationS01-2(19S4) Electromagnetic compatibtity forindustrial-process measurement and control equipment,Part 2: Electpxtatic discharge requiremems, as there is noIndian Standard avaifableon the subject at present.

B-10 ELECTROMAGNETIC SUSCEPTIBILITY

B-10.1 Test Procedure

The EUT shall be exposed to an electromagneticfield strength as specifiedby the severity level.

B-10.1.1 The field strength may be generated invarious ways:

—

—

—

the stripline is used at low frequencies (below30 MHz or in some cases 150MHz) for smallEUTS:the longwire is used at low frequencies (below30 MHz) for larger ELJT’s;dipole antennas or antennas with circularpolarization placed 1m from the EUTare usedat high fr(xpencies.

B-10.L2 The specified field strength shall beestablished prior to the actual testing (withoutEUTin the field).At least 1m of all external cables

13

-’-/1’.,

.1..-,.-_=

IS 14439 (Part 1) :1997

shall be included in the exposure by stretching themhorizontally out from the EUT.

B-10.1.3 The field shall be exposed in twoorthogonal polarizations and frequencyrange shallbe scanned slowly. If antennas with circularpolarization (that is a log-spiral or a helicalantenna) are used to generate the electromagneticfield,a change in the positicmof the antennas is notrequired. When the test is carried out in a shieldedenclosure to comply with international lawsprohibiting interference to radio communications,care needs to be taken to control reflections fromthe walls. Anechoic shielding maybe necessary.At least 1m ofwiring to and from the EUT shall beexposed.

—i

B-10.2 Test Severity

The followingseverities shall apply

~~ ‘quarewaveI

NOTE —For fulltest detailareference maybe made to IECPublicationS01-3(1984) Electromagnetic compatibilityforindustrial-process measurement and control equipment,Part 3: Radiated electromagnetic field requirements, asthere is no Indian Standard available on the subject atpresent.

14

Bureau of Indian Standards

INS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promoteharmonious development of the activities of standardization, marking and quality certification of goods andattending to conneeted matters in the country.

Copyright

BE3 has the copyright of all its publications. No part of these publications may be repmduccd in any formwithout the prior permission in writing of BIS. This does not preclude the free use, in the course ofimplementing the standard, of neeessary details, such as symbols and sizes, type or grade designations.Enquiries relating to copyright be addressed to the Director (Publication), BIS.

Review of Indian Standards

Amendments are issued to standards as the need arises on the basis of comments. Stmdards are also reviewedperiodically; a standard along with amendments is reaffirmed when such review indicates that no changes areneeded; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standardsshould ascertain that they are in possession of the latest amendments or edition by referring to the latest issueof ‘BIS Handbook’ and ‘Standards Monthly Additions’

This Indian Standard has been developed from Dot: No. LM 06( 0276).

Amendments Issued Since Publication

Amend No. Date of Issue Text Affected

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RintcdatsiOlcORintiag Rul, Dcnli, radia

-. _ .—__________ ._1<—! ‘, 1 r“, I