IS 15676: Flow measurement of natural gas by turbine meter

2006·2 MB·English

by  Bureau of Indian Standards

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“The Right to Information, The Right to Live” “Step Out From the Old to the New”
IS 15676 (2006): Flow measurement of natural gas by turbine
meter [PGD 26: Weights and Measures]
“!ान $ एक न’ भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee””
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै”
Bhartṛhari—Nītiśatakam
“Knowledge is such a treasure which cannot be stolen”

IS 15676:2006
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Indian Standard
FLOW MEASUREMENT OF NATURAL GAS
BY TURBINE METERS
lCS 75.160.30; 75.180.30
(3 BIS2006
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002

June 2006 Price Group 8
Weights and Measures Sectional Committee, PG26
,, I
FOREWORD
This Indian Standard was adopted bythe Bureau ofIndian Standards, afterthe drafl finalized bythe Weights and
Measures Sectional Committee hadbeen approved bytheProduction andGeneral Engineering Division Council.
This standard istaken for measuring the gasconsumption atbulk supplier aswell asthe users’ end when thegas
issupplied through the pipelines. Inorder to meetthe requirement ofbulk supplier and consumer, the Bureau of
Indian Standards, has formulated the above standard for accuracy of metering system and regulation of gas at
different delivery point -tofilfill the consumer satisfaction. This standard deals with installation conditions,
leakage, testing and pressure testing and provides a series of information as well as recommendation for use,
field checks and perturbations ofthe fluid flow.
Inpreparing this standard considerable amount of assistance has beentaken from the following publications:.
1S0 9951 :1993 Measurement of gas flow inclosed conduits —Turbine meters
AGA 7American gas authority report forturbine meters
Annexes A, B, C, Dand E are for information only.
For the purpose of deciding whether aparticular requirement of this standard is complied with, the final value,
observed or calculated expressing the result of a test or analysis, shall be rounded off in accordance with
IS2:1960 ‘Rules for rounding offnumerical values (revised’. The number ofsignificant places retained inthe
rounded off value should be the same asthat ofthe specified value inthis standard.
1S15676:2006
Indian Standard
FLOW MEASUREMENT OF NATURAL GAS
BY TURBINE METERS
1 SCOPE 3 DEFINITIONS
Thisstandardspecifiestherequirements ofdimensions, 3.1’ Forthepurposeofthisstandard,followingbasicand
ranges, construction, performance, calibrati-on and general terms in metrology apply. The following
output characteristics of turbine meters for gas flow definitionsaregivenonlyfortermsusedinsomespecial
measurement for custody transfer. senseorfortermswhosemeaningitseemsusefil torecall.
Italsospecifies installation conditions, Ieakagetesting 3.1.1 F’lowrate-Actual volumeofflowperunitoftime.
andpressuretestingandprovides aseriesofinformative
Annexes A to E including recommendations for use, 3.1.2 Working. Range — Range of flowrates of gas
field checks and perturbations ofthe fluid flowing. limitedbythemaximumflowrateqMUandthe minimum
flowrate qMi~for which the meter error lies within
This standard does not cover tie equipment used in
specified limits(sometimes alsocalled ‘rangeability’).
the determinations of the pressures, temperatures,
densities and other variable that rtiustbeknown forthe 3.1.3 Designated Flow Range — Flow between
accurate determination ofmeasured gas quantities. 0.2 qM~X‘0qMin.
tn cases where conflict exists between mandatory 3.-1.4Metering Pressure — Gaspressure inameter to
regulations and this standard, the former shallprevail. which the indicated volume ofgas isrelated.
2 REFERENCES 3.1.5 Average Velocity — Volumeflowrate per unit of
cross-sectional area.
The following standards contain provisions which,
through reference inthis text, constitute provisions of 3.1.6 Shell — Pressure-containingstructureofthemeter.
this standard. At the time of publication, the editions
3.1.7 Metering Conditions — Conditions, atthepoint
indicated were valid. All standards are subject to
of measurement, of the gas whose volume ik to be
revision and parties to agreements based an this
measured, for example, gastemperature and pressure.
standard are encouraged to investigate the possibility
of applying the most recent editions of the standards 3.1.8 Base Conditions — Conditions to which the
indicated below: measured volume ofthegasisconverted (for example,
base temperature and base pressure).
Standard No. Title
IS 1076(Part 1): Preferred numbers :Part 1,Seriesof 3.1.9 Specl~ed Conditions — Conditions ofthegasat
which performance specifications of the meter are
1985 preferred numbers (second revi.sion)
given.
IS2148:2004 Electricalapparatusforexplosivegas
atmospheres — Flameproof NOTE — Metering and base conditions relate only to the
enclosures “d” (third revision) volumeofthegastobemeasuredorindicated, andshouldnot
1S04006 :1991 Measurement of fluid flow in be confused with ‘rated operating conditions’ or ‘reference
conditions’ (VIM 5,05 and 5.07), which refer to influence
closed conduits — Vocabulary and
quantities (VIM2.10).
symbols
1S0 5167-1 Measurement offluidflowbymeans 4 SYMBOLS AND SUBSCRIPTS
1991 of pressure differential devices —
SeeTable 1.
Part 1 :Orifice plates, nozzles and
venturi tubes inserted in circuIar 5 PRINCIPLE OF THE METHOD OF
cross-section conduits minning full
MEASUREMENT
1S05168 :1978 Measurement of fluid flow —
.
A turbine meter is a fluid flow measuring device in
Estimation of uncertainty of aflow-
rate measurement which the dynamic forces of the flowing fluid cause
1S0 5208:1993 Industrial valves— Pressure testing theturbine wheeltorotate with aspeed approximately
of valves proportional totherateofvolume flow.The number of
1S0 6708:1980 Pipe components — Definition of revolutions of the turbine wheel is the basis for the
nominal size indication ofthe volume passed through the meter.
1S15676:2006
TaMel Symbols and Subscripts
(Clause 4)
Symbol Quantity Dimensions S1llnit
(1) (2) (3) (4)
Symbol
p
Pressurelosscoefficientdependingonmetertype ni’
: Relativedensityofthegas(d,i,= 1) Dimensionless —
D Insidediameterpipeoutlethrlet “L m
D, Insidediameterpipe L m
DN “Nominalsizemeteroutlet/iniet Dimensionless —
DA’, Nominal sizepipe Dimensionless —
H Heightorstrut L m
L Lengthoftbestrut L
Mass M :g
: Molarmass M kg/mol
N Number ofmolesof-gas Dimensionless mol
P Absolutepressure MI.-’Tz Pa
Pm Metering pressure M~-l ~2 Pa
Flowrate L.? ~1 n+Is
; Molargasconstant MLI p @ J/(mol-K)
s Chorddistancebetweenadjacentstrutsmeasuredatthetip L M
t Time T s
T Absolutetemperatureofthe.gas o MK3
v Volume L’
—
z Compressibilityfactor(deviationfromidealgaslaws) Dimensionless
ML.,
P Densityofthegas kg/m’
v Workingrangeqtdqm,, Dimensionless —
Subscripts
b Baseconditionsforvolumeorratecalculations
m Meteringconditions.ofthegas
s Specifiedconditionsforvolume orrate
A second turbine wheel may be included in the per hour (m3/h) of the meter shall preferably be a
mechanism, designed to rotate atasignificantly slower number ofthe preferred series [see IS 1076 (Part 1)].
speedthanthefirstduetothedifference inblade angles The unit of cubic metres per hour (m3/h)ispreferred.
ofthetworotors. Achange inrotational speedbetween
7 METER CONSTRUCTION
the tworotors for agiven fluid velocity will indicate a
shift in calibration conditions, for example, a change 7.1 General
inbearing friction, flowpulsations or achange inflow
Metersshallbedesigned andmanufacturing tolerances
profile.
shallbesettoallowinterchangeability ofmeters ofthe
Schematics ofaxial-flow gasturbine meters areshown same size andtype.
inFig. 1.Gas entering the meter increases invelocity
through the annular passage formed bythe nose cone 7.2 Materials
and the interior wall of the body. The movement of
The meter body and the internal mechanism shall be
gas over the angled rotor blades imparts a force to
manufactured of materials suited for the service
the rotor, causing it to revolve. The ideal rotational
conditions and resistant to attack by the fluid which
speed is directly proportional to the flowrate. The
the meter isto handle. Exterior surfaces of the meter
actual rotational speed isafunction ofthepassageway
shallbe protected asnecessary against corrosion.
size and shape, and the rotor design. It is also
dependent upon the load, that is, imposed due to 7.3 Shell
internal mechanical friction, fluid drag, external
Themeter shellandallotherpartscomprising thefluid-
loading, and the gas density.
containing structure ofthe meter shall be constructed
ofsoundmaterials anddesignedtohandle thepressures
6 FLOW M-ETER
andtemperatures for which they are rated.
The maximum and minimum flowrates shall be
7.4 Connections anti Maximum Flowrates
specified for the gasdensities forwhich themeter will
operatewithin thespecifications ofmeter performance The inlet and outlet connections of the meter shall
defined in 3. The maximum flowrate in cubic metres conform to recognized standards (see Table 2).

2
IS 15676:2006
‘BODY
\
q
IEIIZI(KIEJ eEND
cONNECTION
~
-
(IL Ell )
OUTLET
NOSE CONE
—1 Id’
.-
v
MECHANISM
HOUSING AND
TAILCONE
BODY END CONNECTION
INLET ~
TURBINE ROTOR
FIG. 1SCHEMATICDRAWINGSOFAXIAL FLOWGAS TURBINEMETERS
Table 2 Preferred Nominal Sizes (DN) and Corresponding Maximum
Flowrates at Metering Conditions (q~~,)
(Clause 7.4)
S1No. Maximum Flowrates at Metering Conditions Nominal Size, DN
m3h
mm
(1) (2) (3)
i) 40 50
ii) 65 50
iii) 100 50
iv) 160 80
v) 250 80
vi) 400 100
vii) 650 150
viii) 1000 150
ix) 1600 200
x) 2500 250
xi) 4000 300
xii) 6500 400
xiii) I0000 500
xiv) 16000 600
xv) 25000 750
xvi) 40000 “1000
NOTE— Meter sizesaredesignated byG16,G40,etc,acc ordingtoOIMLR-32,
3
1S15676:2006
7.5 Length construction ofthe meter asspecified inthis clause is
maintained.
The length of the meter “betweenthe ends of its inlet
and outlet connections shall be less than or equal to 7.8.3 Each removable meter mechanism shall have a
5D of meter sizes greater than 25 mm. unique serial number marked on it.
7.8.4 Eachremovablemetermechanismshallbecapable
7.6 Pressure Tappings
ofbeingsealedagainstunauthorized interference.
7.6.1 A4etering-Pressure Tappings
7.9 Overloading
Atleastonemetering pressuretappingshallbeprovided
Themetershallbedesignedtobecapableofoccasionally
on the meter, to enable measurement indirectly if
running20percent abovethemaximum flowratewithin
necessary ofthe static pressure atthe turbine wheel of
the range of pressure and temperature for which it is
the meter at metering conditions. The connection of
rated, for a time period of 30 min without damage or
thispressure tapping shallbemarked ‘pm’.Ifmorethan
without influenceonthe error curve ofthe meter.
one ‘p~’tapping isprovided, thedifference inpressure
readings shallnot exceed 100Paatmaximum flowrate
8 PRESSURE TESTING
with an air density of 1.2kg/m3.
8.1 General
7.6.2 Other Pressure Tappings
8.1.1 The pressure testing shallbe based on the shell
Ametershallbeequippedwithotherpressure-tappingsin test for industrial valves asspecified in1S0 5208.
additiontothe ‘pm’tapping.Theseservetodeterminethe
8.1.2 Meters shallnotbepainted orotherwise coated
pressuredropoverametertappings shallbemarked‘p,ri’.
with materials capable of sealing against leakage
before leakage tests are completed. Chemical
7.6.3 Dimensions
corrosion protection treatments and internal linings
7.6.3.1 Circular tappings shall conform to the are permitted. If pressure tests in the presence of.a
requirement given in1S05 167-1exceptthattheyshall representative ofthe purchaser are specified, painted
haveminimum bore diameter of3mmandamaximum meters from stock may be retested without removal
bore diameter of 12 mm, and the length of the bore of paint.
shall be a minimum of one bore diameter.
8.1.3 Test equipment shall not subject the meter to
7:6.3.2 Slit-shaped tappings shall have a minimum externally applied stress which may affect the results
dimension of 2 mm and a maximum dimension of ofthe tests.
10mm inthe direction of flow,and aminimum cross-
sectional area of 10mm2. 8.2 Test F)uid
8.2.1 Thetestmaybecarried outwithwater,kerosene,
7.6.4 Sea[ing
or any other suitable liquid having a viscosity not
Any pressure test point or tapping connection on the greater than that ofwater or with gas(air or any other
meter shall be provided with a suitable means of suitable gas).
closure, for example, a plug, and shall be capable of
8.2.2 When testing with a liquid, the meter shall be
being sealed against unauthorized interference.
thoroughly purged of anyair which itcontains.
7.7 Flow Direction
8.3 Strength Test of the Pressure-Containing Parts
The direction offlow orthe inlet ofthe meter shall be
8.3.1 Thetestshallbeperformed ataminimum internal
clearly and permanently marked.
pressureof 1.5timesthemaximumallowable operating
pressure atambient temperature.
7.8 Meter Having aRemovable Meter Mechanism
8.3.2 Thetestshallbeperformed byapplying pressure
7.8.1 The construction of a meter with a removable
inside the pressure-retaining walls of the assembled
meter mechanism shall be such that the performance
meter with the connections closed.
characteristics of the meter as defined in 3.1 are
maintained after interchange of the mechanism and/or 8.3.3 There shall be no visually detectable leakage
after repeated mounting and dismounting of the same through the pressure-retaining walls is not
mechanism. acceptable.
7.8.2 The design and method of replacement of.a Thetestduration shallnotbelessthanthat specified in
removable mechanism shall ensure that the Table 3.

4
IS 15676:2006
Table 3 Strength Test Duration
(Clause 8.3.3)
s]No. Nominal Size, Minimum Test Duration
DN
(1) (2) &
O DN =50 15
ii) 50<D/vs 200 60
iii) DN>200 180
8.4 Meter Leakage Test that are above qMn.O.1;0.25; 0.4; 0.7 of qm
~d qMW;
The assembled meter shall be pneumatically tested
b) name and location ofthe calibration facility;
for external leakage at minimum internal pressure of
1.1times themaximum allowable operating pressure. c) method of calibration (bell prover, sonic
The pressure shall be increased slowly up to the test nozzles, other meters, etc);
pressure and shall bemaintained there for aminimum d) estimated uncertainty ofthe method;
of 1min. During this period no fluid shall escape from e) nature and conditions (pressure and
the meter. If a leakage test is run after a hydrostatic temperature) ofthe test gas; and
test, awater seal could develop, therefore, the meter
t) position ofthemeter(horizontal, vertical flow
shall be dried before assembling the mechanism and
upwards, vertical flow downwards).
carrying out the leak test. After the test, the pressure
shall be released at a rate not greater than that used 9.2.2 Calibration Conditions
for pressurization.
The calibration ispreferably .carried out atconditions
asclose aspossible to operating conditions.
9 PERFORMANCE CHARACTERISTICS
9.2.3 Calibration Facility
See also Annex C.
The facility atwhichthe calibration iscarried outshall
9.1 Error betraceable to the primary standards of mass, length,
time and temperature.
The relative error, E, inpercent, isdefined asthe ratio
of the difference between the indicated value Vi,,~of 9.2.4 Installation Conditions at Calibration
thevolume ofthetestmediumwhichhaspassedthrough
The performance of the meter shall not be influenced
the gas meter, to this latter value:
bythe installation conditions ofthe test facility.
~ = ynd – ‘true 9.2.5 Meter shall conforms to accuracy of+1percent
vtrue over a specified flow range for any operating density.
Allmeters shall have amaximum permissible error of Turbine meters are capable of*0.25 percent accuracy
+I percent over the designated flow range. Between over a specified flow range if they are individually
qvi,,to0.2q~~ythepermissibleerrorshallbe+2percent. calibrated against an acceptable standard at the
particular density at which they will be operated.
A meter isconsidered to satisfy this requirement, if it
Therefore, themostaccurateturbinemeterperformance
ismet atthe flowrates.
isobtained wheneachmeter iscalibrated under density
The density range for which the relative errors are conditions approaching the meter’s actual operating
within these allowances shall be specified. density. If meter calibration at operating density is
impractical,itisnecessarytorelyonthemanufacturer’s
For the calculation or errors, see1S05 168.
prediction of the calibration shift to be expected
‘
9.2 Calibration between the calibrating and operating densities.
Anindividual calibration ofeachmeter shaIlbemade. 9.2.6 Determination of Calibration Factor
The results of this calibration shall be available on Itisageneral practice, and most convenient, to use a
request, together with astatement of conditions under fixed meter calibration factor over the whole range of
which the calibration took place. flowrates. This will beacalibration factor ‘K’(pulses
per unit volume) for an electrical output, For
9.2.1 Calibration Data
mechanical output meters, thefactor issetbychoosing
The calibration data provided shall include: change gears that make each meter output shaft
revolution represent a definite volume, for“example,
a) error at qM,nand all the following flowrates
0.085 or 0.85 m3atflowing conditions.

5