SIST ISO 4269:2006
(Main)Petroleum and liquid petroleum products -- Tank calibration by liquid measurement -- Incremental method using volumetric meters
Petroleum and liquid petroleum products -- Tank calibration by liquid measurement -- Incremental method using volumetric meters
This International Standard specifies a method for the calibration of tanks by addition of batches of liquid. The liquid is
used as a volume-transfer medium, measured accurately by means of a meter.
This International Standard is not applicable to the calibration of reference measuring instruments, proving tanks, or
meter provers.
NOTE Applicable standards are given in the bibliography.
Pétrole et produits pétroliers liquides -- Jaugeage des réservoirs par épalement -- Méthode par empotement utilisant des compteurs volumétriques
La présente Norme internationale prescrit des méthodes de jaugeage des réservoirs par ajout de quantités
connues de liquide. Le liquide est utilisé comme intermédiaire pour le transfert de volume, et mesuré avec
exactitude au moyen d'un compteur.
La présente Norme internationale ne s'applique pas à l'étalonnage des instruments de mesure de référence, des
jauges étalons et des tubes étalons.
NOTE Les normes applicables sont données dans la bibliographie.
Nafta in tekoči naftni proizvodi – Umerjanje rezervoarjev s tekočim merjenjem – Postopna metoda z uporabo volumetrov
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-februar-2006
1DIWDLQWHNRþLQDIWQLSURL]YRGL±8PHUMDQMHUH]HUYRDUMHYVWHNRþLPPHUMHQMHP±
3RVWRSQDPHWRGD]XSRUDERYROXPHWURY
Petroleum and liquid petroleum products -- Tank calibration by liquid measurement --
Incremental method using volumetric meters
Pétrole et produits pétroliers liquides -- Jaugeage des réservoirs par épalement --
Méthode par empotement utilisant des compteurs volumétriques
Ta slovenski standard je istoveten z: ISO 4269:2001
ICS:
75.180.30 Oprema za merjenje Volumetric equipment and
prostornine in merjenje measurements
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
INTERNATIONAL ISO
STANDARD 4269
First edition
2001-03-15
Petroleum and liquid petroleum products —
Tank calibration by liquid measurement —
Incremental method using volumetric
meters
Pétrole et produits pétroliers liquides — Jaugeage des réservoirs par
épalement — Méthode par empotement utilisant des compteurs
volumétriques
Reference number
©
ISO 2001
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ii © ISO 2001 – All rights reserved
Contents Page
Foreword.iv
Introduction.v
1 Scope .1
2 Normative references .1
3 Terms and definitions .2
4 Precautions .2
5 Meters .2
6 Apparatus .4
7 Calibration procedure .5
8 Corrections to observed volumes.8
9 Calculation of tank capacity tables.9
10 Requirements for calculations .10
Annex A (normative) Correction for thermal effects .12
Annex B (informative) Field data and calculation sheets.18
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 4269 was prepared by Technical Committee ISO/TC 28, Petroleum products and
lubricants, Subcommittee SC 3, Static petroleum measurement.
Annex A forms a normative part of this International Standard. Annex B is for information only.
iv © ISO 2001 – All rights reserved
Introduction
This International Standard forms part of a series on tank calibration including the following:
ISO 7507-1, ISO 7507-2, ISO 7507-3, ISO 7507-4, ISO 7507-5, ISO 7507-6, ISO 8311, ISO 9091-1 and
ISO 9091-2.
Liquid calibration methods may be used in the calibration of either the total or partial capacity of a tank. A high degree
of accuracy may be obtained provided that great care is taken at all stages of the operation. The method is particularly
useful where tanks are of irregular shape, for the calibration of the bottom of any storage tank, or for the calibration of
ship and barge tanks having irregular cross sections.
The method offers a degree of accuracy which may exceed other methods when used in the calibration of small tanks,
especially small horizontal cylindrical tanks.
The calibration liquid may be either water or a suitable petroleum product having a low volatility and viscosity. Water is
recommended where wide temperature variations are expected during calibration as water has a low coefficient of
cubical expansion. However, the use of water may introduce unacceptable risks and difficulties depending on the use
to which the tank being calibrated is to be put (e.g. the use and subsequent removal of water when used in the
calibration of underground storage tanks at retail sites). In such circumstances the use of a suitable petroleum product
would be preferable.
INTERNATIONAL STANDARD ISO 4269:2001(E)
Petroleum and liquid petroleum products — Tank calibration by
liquid measurement — Incremental method using volumetric
meters
1 Scope
This International Standard specifies a method for the calibration of tanks by addition of batches of liquid. The liquid is
used as a volume-transfer medium, measured accurately by means of a meter.
This International Standard is not applicable to the calibration of reference measuring instruments, proving tanks, or
meter provers.
NOTE Applicable standards are given in the bibliography.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 91-1:1992, Petroleum measurement tables — Part 1: Tables based on references temperature of 15 °C and
60 °F.
ISO 91-2:1991, Petroleum measurement tables — Part 2: Tables based on a reference temperature of 20 °C.
ISO 2714:1980, Liquid hydrocarbons — Volumetric measurement by displacement meter systems other than
dispensing pumps.
ISO 2715:1981, Liquid hydrocarbons — Volumetric measurement by turbine meter systems.
ISO 4268, Petroleum and liquid petroleum products —Temperature measurements — Manual methods.
ISO 7507-1:1993, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks — Part 1:
Strapping method.
ISO/TR 7507-6:1997, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks — Part 6:
Recommendations for monitoring, checking and verification of tank calibration and capacity tables.
ISO 9770:1989, Crude petroleum and petroleum products — Compressibility factors for hydrocarbons in the range
3 3
638 kg/m to 1074 kg/m .
IEC 60079-10, Electrical apparatus for explosive gas atmospheres — Part 10: Classification of hazardous areas.
3 Terms and definitions
For the purposes of this International Standard, the terms and definitions given in ISO 7507-1, and the following, apply.
3.1
K-factor
number of pulses generated by a meter per unit of volume passing through it
3.2
pre-set device
equipment which shuts off the delivery of calibration liquid to the meter after a predetermined volume has passed
through the meter
4 Precautions
4.1 The general precautions and safety precautions in ISO 7507-1 and IEC 60079-10 shall apply to this
International Standard.
4.2 When a petroleum product is used as the calibration liquid, the following additional safety precautions, which
are not exhaustive, shall be observed:
a) control of sources of ignition;
b) prevention of electrostatic accumulation by
1) the correct bonding of transfer hoses,
2) control of pumping speeds,
3) prevention of free fall and splashing of liquid,
–
4) maintenance of the velocity of the liquid in the line below 1 ms until the end of the filling pipe is submerged.
5 Meters
5.1 General specifications
5.1.1 The meter shall be of the positive displacement or turbine type.
5.1.2 The meter shall be fabricated from materials suitable for the calibration liquid to be used.
5.1.3 The meter shall be selected so that the flow rate, at which the meter will operate during the tank calibration,
is within the linear range of the meter factor curve of the meter.
The meter should either be fitted with a flow-rate indicator, or average flow rates should be calculated by timing
deliveries by means of a stop watch.
5.1.4 The meter shall have either a device giving a read-out in volumetric units or an electronic pulse counter
used to calculate volume.
To enable the required repeatability to be determined during the proving of the meter, and depending on the
volume passed by the meter during such proving, a special counter or other indicator capable of being read to a
fraction of the unit of volume should be provided.
2 © ISO 2001 – All rights reserved
5.1.5 A volumetric proving tank, a pipe prover or a small volume prover, suitable for use with the type of meter
chosen, shall be provided for calibrating the meter. The selected apparatus shall be provided with a calibration
certificate showing any corrections which may be required when in use.
5.1.6 A thermowell (thermometer pocket) shall be provided in the metering system adjacent to the meter.
To ensure adequate immersion and thermal response, and to avoid undesirable thermal conduction effects from
the pipe wall, it is recommended that, particularly in the case of small diameter lines, the pocket should be installed
in the body of the meter if a positive displacement meter is used. If a turbine meter is used, then the thermowell
shall be installed in the pipework at least five pipe diameters downstream of the meter position. The thermowell
should be in direct contact with the calibration liquid and should be filled with a light oil to aid thermal response. The
thermowell, and the fitting in which the sensitive element of the thermometer is immersed, should be designed in
accordance with sound thermo-technical principles. It may be desirable to provide external insulation round the
pipe or fitting at the position of, and adjacent to, the thermowell.
5.1.7 A rapid operating valve or shut off device shall be installed downstream of the meter (see 6.4.5).
5.2 Positive displacement meters
The meter factor shall not deviate by more than � 0,20 % from the average meter factor between 10 % and 100 % of
the maximum rated flow rate of the meter.
5.3 Turbine meters
5.3.1 The K-factor shall not deviate by more than � 0,20 % between 10 % and 100 % of the maximum capacity
of the meter.
5.3.2 A back pressure in excess of 100 kPa (gauge) shall be applied in order to prevent cavitation.
5.4 Selection of meter
5.4.1 The selection of a meter for tank calibration is contingent on the following:
a) the operating rate of flow to be used when calibrating the tank (see 5.4.4);
b) the maximum pressure to which the meter will be subjected;
c) the liquid which the meter is required to measure (see 5.1.2);
d) the temperature range over which the meter will operate;
e) the range of viscosities over which the meter will operate.
5.4.2 Meters incorporating a temperature compensator shall not be used for tank calibration.
5.4.3 The meter shall be provided with a meter factor or K-factor curve (error–flow curve) for the type of liquid,
viscosity, temperature and range of flow rates over which it will be used.
5.4.4 The repeatability of the meter shall be such that the results of five consecutive proving runs shall be within
arangeof � 0,025 % of the average after correcting for temperature, pressure and viscosity.
5.4.5 Meters shall be installed and operated in accordance with the appropriate recommendations contained in
ISO 2714 or ISO 2715.
6 Apparatus
6.1 Dip-tape and dip-weight
This shall be as specified in ISO 7507-1:1993, B.6 and B.7.
6.2 Ullage paste
NOTE The term "oil-finding paste" is synonymous.
6.3 Water-finding paste
6.4 Ancillary equipment
6.4.1 Air/vapour separator
An air separator, when utilized, shall be fitted upstream of the meter.
A back-pressure valve may be required to maintain an adequate pressure drop across the air release valve fitted to
the air separator.
6.4.2 Flow limiter
A flow limiting device shall be fitted in the line, downstream of the meter, to limit the rate of flow if the pressure of the
calibration liquid supply is such that the flow rate through the installation is too great for the rated capacity of the meter.
6.4.3 Pre-set device
The pre-set device should be leak proof and operate quickly with a smooth action, without causing any undue
pressure surge.
6.4.4 Pressure gauge
Where a positive displacement meter is used, a pressure gauge shall be mounted in the line as close to the meter as
possible, preferably on the downstream side. Where a turbine meter is used, a pressure gauge shall be installed at
least five pipe diameters downstream from the meter. It may be preferable that two pressure gauges are installed
equidistant from the meter upstream and downstream
6.4.5 Shut-off valve
The valve shall be leak proof, and shall operate quickly with a smooth action and without causing an undue pressure
surge.
If a pre-set device is not fitted, a shut-off valve, to shut off the flow at the required intervals, shall be installed
downstream of the meter.
6.4.6 Strainer
6.4.7 Surge suppressor
If surge pressures are likely to occur, a suitable surge suppressor should be fitted to the line.
6.4.8 Syphon breaker
If fitted, the syphon breaker shall be downstream of the meter as close to the delivery point as is possible.
When a tank is being calibrated by top filling, then the syphon breaker should be installed in conjunction with a
weir. The assembly should be fitted at the highest point in the system.
4 © ISO 2001 – All rights reserved
6.4.9 Viewing glass
A viewing glass shall be provided adjacent to/in the air separator if utilized.
6.4.10 Weir
If installed, the weir shall be positioned in such a way as to ensure that the delivery pipe downstream of the meter is full
at all times.
7 Calibration procedure
7.1 General requirements
7.1.1 A tank shall only be calibrated after it has been filled at least once with a liquid of density equal to or
greater than that which it will hold when in use.
NOTE The hydrostatic test applied to new or repaired tanks will satisfy this requirement in most cases.
7.1.2 Before commencing calibration, the system shall be checked for leakage downstream of the meter. Any
leaks found shall be eliminated.
7.1.3 The serial numbers, or identification marks, of thermometers used in the course of calibration shall be
recorded together with their location during the calibration. The thermometers shall be calibrated in accordance
with ISO 4268 and shall be provided with a certificate showing corrections.
7.1.4 Care shall be exercised to avoid the ingress of air into the system when using a meter to calibrate a tank.
It is important that the meter, ancillary equipment and lines be liquid filled before the commencement of calibration.
7.1.5 If fitted, a strainer/filter shall be installed in the line upstream of the meter to protect the meter from
abrasion or other damage from entrained foreign matter.
7.1.6 If the variation of the volume of calibration liquid in the hose connecting the meter to the tank, compared
with the total volume of liquid in the tank, is such that the accuracy of the calibration would be significantly affected,
a syphon breaker shall be placed at the end of the hose to ensure that the hose remains filled with a constant
quantity of liquid.
7.1.7 Excessive variations in the temperature of the calibration liquid shall be avoided if the required accuracy is
to be maintained.
Large fluctuations make it difficult to determine an accurate mean temperature and this in turn causes the following:
a) uncertainties in applying the volume correction factors to the liquid;
b) uncertainties in applying the correction factor for the expansion/ contraction of the measuring equipment;
c) uncertainties in applying the correction factor for the expansion/ contraction of the tank being calibrated.
7.1.8 An adequate supply of the calibration liquid shall be available. The pressure available shall be sufficient, at
all times, to maintain stable flow rates within the normal operating range of the meter.
7.1.9 If a petroleum product is used as the calibration liquid, its depth in the tank shall be measured with product-
finding paste applied in a smooth even film to the dip-tape and dip-weight.
7.1.10 If water is used as the calibration liquid, its depth in the tank shall be measured with water-finding paste
applied in a smooth even film to the dip-tape and dip-weight.
7.1.11 The exact height of the upper reference point above the dip-point shall be determined at the time of
calibration. The overall dipping height shall be marked on the roof of the tank at or near to the dip hatch to which it
applies.
In tanks with a single dip point, the upper reference point shall be clearly marked on the tank and its height above the
dipping datum point shall be recorded at the head of the table. In tanks with more than one dip point, the overall height
at each dip point shall be clearly marked adjacent to the point. This measurement may require adjustment to correct for
the difference between the actual and the certified reference temperature of the dip-tape and dip-weight used to
measure the overall dipping height. The correction shall be calculated in accordance with the equation given in A.3.
7.1.12 If the calibration of the tank is interrupted, it may be resumed at a later date provided that
a) if there is a change of equipment or personnel, sufficient check measurements are made to ensure that the
results obtained prior to the changes correspond within the tolerances laid down in this method,
b) all records of work previously carried out are complete and legible, and
c) the new liquid mean temperature and depth at resumption of operations are recorded.
7.2 Equipment
The calibration of a tank may not necessarily require all of the equipment listed in clause 6. The requirements for each
operation shall be considered before selecting equipment.
7.3 Installation
7.3.1 Figure 1 shows a schematic diagram of a typical installation for calibration by meter.
7.3.2 Attention shall be paid to pipework to ensure minimum pressure drop and turbulence.
Any condition which tends to increase the turbulence of the liquid stream should be avoided.
7.3.3 The meter shall be installed in such a manner that no undue strain is imposed upon it due to the mass or
thermal expansion/contraction of the pipework.
7.3.4 Flexible hoses may be used to provide a supply of liquid for calibration purposes. If they are used on the
downstream side, the total length shall be kept to a minimum.
7.4 Meter proving
7.4.1 The meter shall be proved, on site, using either a volumetric prover tank, meter or pipe prover.
Proving should preferably be carried out using the same fluid as that in the tank.
7.4.2 Proving shall be carried out, as a minimum, immediately prior to commencement and on completion of any
calibration. If the calibration process extends over more than one day, the meter shall be proved at commencement
of calibration and on completion of calibration on each day. Proving may be carried out at shorter intervals to
ensure that the meter or K-factor has not drifted.
NOTE Proving at a central proving station/installation may be acceptable if meters are proved under conditions which
closely replicate those encountered at the calibration site.
6 © ISO 2001 – All rights reserved
Key
1 Tank to be calibrated
2 Flow limiter
3 Non-return valve
4 Thermometer
5 Pressure gauge
6 Air/vapour separator
7 Strainer
8 Supply
9 Meter
10 Syphon breaker
a
To air/vapour separator.
b
To vent.
Figure 1 — Schematic diagram of a typical installation for calibration by meter
7.5 Calibration procedure
7.5.1 The calibration liquid shall be transferred into the tank at a flow rate for which the meter has been
calibrated and at such a rate as to minimize disturbance of the liquid surface in the tank.
Care should be taken during the initial filling of the system to avoid over-ranging of the meter when the air in the
system is being displaced. If flow rates are likely to exceed the rated capacity of the meter, a suitable flow control
valve should be fitted downstream of the meter (see 6.4.2).
7.5.2 The calibration liquid shall be added in incremental volumes sufficient to produce a significant change in
the liquid level with reference to the section of the tank being calibrated, and having due regard to the uncertainty
of liquid level gauging.
NOTE During calibration, the increase in the liquid level is dependent on the size of the liquid volumes introduced into the
tank; i.e. the liquid level is the dependent variable. In a capacity table, the liquid level is the independent variable; the calculation
of the table from field measurements is dependent on the size of the increments added to the tank and to the interpolation
techniques used to calculate the capacity table. Care should be exercised to ensure that the incremental volumes added to the
tank during calibration are of a size which ensures a significant movement in the liquid level but are small enough to minimize
the uncertainty arising from the interpolation technique used in calculating the capacity table.
7.5.3 After the addition of each increment, the liquid surface shall be allowed to settle and the liquid depth
measured at the dip-point by use of a dip-tape and dip-weight.
Liquid depth measurements shall be made and recorded to the nearest millimetre. The depth measurement shall be
taken and shall be repeated. The two measurements shall agree to within 1 mm. If the readings differ from each other
by more than 1 mm, then the depth measurements shall be repeated until two consecutive readings are within the
tolerance limit.
NOTE If ripples on the surface give rise to difficulties in making measurements, a ripple damping device may be used.
7.5.4 After each increase in depth has been measured and recorded, the temperature of the liquid at the meter,
using the thermowell (see 5.1.6) and in the tank shall be taken to the nearest 0,25 °C or better.
NOTE The number of temperature readings may be reduced to one in every five increments if the temperature is found to
be constant.
7.5.5 The ambient air temperature in close proximity to the tank being calibrated shall be measured to the
nearest 0,25 °C, or better, at intervals throughout the calibration period. The recorded temperatures shall be taken
at intervals of time which will accurately reflect the ambient air temperature throughout the calibration process.
7.5.6 If a petroleum product is being used as a calibration liquid, then the pressure on the liquid at the meter
shall be measured and recorded at intervals through out the calibration period. The recorded pressures shall be
taken at intervals of time which will accurately reflect the pressures exerted on the liquid throughout the calibration
process.
7.5.7 If the volume displaced by the inlet hose, compared to the total volume of liquid in the tank, is such that the
accuracy of the calibration would be significantly affected, the inlet hose shall be withdrawn until its lower end is
above the level of the liquid in the tank. Special care and attention shall be exercised to obtain the same amount of
draining before measurements are made of the liquid depth; the liquid surface shall be quiescent.
8 Corrections to observed volumes
8.1 General
Corrections to the observed volumes are required for one or more of the following:
a) calibration error of the meter used;
b) effect of temperature variations on the meter used;
c) effect of temperature variations on the calibration liquid used;
d) effect of temperature variations on the tank being calibrated;
e) effect of temperature variations on the dip-tape and dip-weight used.
If necessary, these corrections shall be calculated and applied when computing a tank capacity table. The tank
calibrator shall ensure that all necessary details for the calculation of the corrections are included in the calibration
notes.
8.2 Meter factor and K-factor
8.2.1 The meter factor or K-factor for the meter in use shall be the average of the factors calculated at the
commencement and completion of the calibration.
8.2.2 The meter factor or K-factor at the commencement and completion of the calibration shall not differ by
more than 0,05 %. If the two factors differ by more than 0,1 % then the reason for the difference shall be
determined and, if necessary, the calibration shall be repeated.
8 © ISO 2001 – All rights reserved
8.3 Temperature changes in the calibration liquid
8.3.1 A correction shall be made for any change in the temperature of the calibration liquid between the time that
it is measured in the meter and the time that it is measured in the tank being calibrated.
8.3.2 If the calibration liquid used is a petroleum product and the tank calibration table is required to be correct at
either 15 °Cor 20 °C, the volume delivered shall be corrected for temperature changes in the calibration liquid by
using the Volume Correction Factor (VCF) table for petroleum products in ISO 91-1:1992 or ISO 91-2:1991
respectively.
8.3.3 If the calibration liquid used is water and the tank calibration table is required to be correct at 15 °C, the
volume delivered shall be corrected for temperature changes in the calibration liquid by using the table of water
densities or the formula given in annex A.
8.3.4 The corrections shall be made in the following order:
a) correction of the observed calibration liquid temperature to reference temperature;
b) correction of the capacity of the container shell for thermal effects;
c) correction of the liquid level measurement/dip-tape and dip-weight for thermal effects.
8.4 Temperature changes in the tank shell
A correction for the difference in temperature between the shell of the tank at the time of calibration and its average
temperature in service, or between the temperature at calibration and a standard reference temperature, e.g. 15 °C,
shall be made according to the method given in annex A. The tank shell temperature shall be determined by one of the
methods given in annex A of either ISO 7507-1:1993 or ISO 7507-6:1997.
8.5 Temperature effects on dip-tapes and other measures of length
Dip-tapes and other measures of length are calibrated at 20 °C but if they are used at other temperatures, within the
range 20 °C � 5 °C, the corrections for temperature changes are small (of the order of 1 mm in 18 m) and may be
neglected in all cases. Outside this range, a correction is required (see A.3).
8.6 Method of correcting for temperature effects
8.6.1 When the total capacity of the tank has been calibrated by meter and the tank capacity table is required to
be at a reference temperature of either 15 °Cor20 °C the corrections in 8.4 to 8.5 may be conveniently combined.
8.6.2 If calibration is required to be correct at some other temperature, the adjustment to the standard
temperature shall first be made and a further correction calculated for the thermal expansion or contraction of the
tank shell shall be in accordance with annex A.
9 Calculation of tank capacity tables
9.1 All calculations shall be made in accordance with accepted mathematical principles.
Errors in calculation are minimized and checking facilitated by the adoption of a standard form of data and
calculation sheet. The use of the forms illustrated in annex B is recommended for site data collection and for
calculation.
9.2 Tank capacity tables
9.2.1 Provided that tank capacity tables have been calculated in accordance with the principles given in this part
of ISO 4269, the format adopted will not affect the mathematical correctness of the table. However, the principles
laid down in this clause are recommended since they provide a table in a form most convenient for use. Each tank
calibrated in accordance with this part of ISO 4269 shall be issued with a certificate of calibration as specified in
ISO 7507-1:1993, annex E.
9.2.2 At the head of each tank calibration table it shall be clearly stated the method by which the liquid level for
entry to the tank capacity table shall be determined.
9.2.3 Table headings shall show the tank reference number and location, the temperature at which the table is
correct, and the date of calibration.
9.2.4 The intervals of dip at which the table is set out shall be chosen so as to allow linear interpolation for
intermediate dips without significant loss of accuracy.
10 Requirements for calculations
10.1 All readings of instruments shall be recorded as observed, without correction for errors which shall be shown
separately. Recorded figures shall be checked for consistency before proceeding to the next entry. In all cases of
doubt, the readings shall be verified.
10.2 Temperature shall be recorded to at least the nearest 0,25 °C.
10.3 Volumetric readings shall be recorded to the nearest graduation on the meter registers.
10.4 All correction factors obtained from tables shall be used without rounding.
10.5 Other correction factors which require to be calculated shall be correct to 5 significant figures.
10.6 All calculations shall be carried out to be correct to at least 5 significant figures.
10.7 Depth measurements which shall be recorded to the nearest 1 mm, and shall be shown corrected to the
nearest 1 mm.
10.8 The final tables shall be calculated by interpolation from the corrected cumulative volumes.
10.9 Final volumes in tank capacity tables obtained by interpolation shall be rounded off to the nearest whole litre
and shown against the required tabular interval of dip or ullage.
10.10 If a petroleum product is being used as a calibration liquid, then the pressure on the liquid shall have been
measured and recorded at intervals throughout the calibration period. If required, a correction for the
compressibility of the liquid used may be calculated using either a factor from Table 1 or from the tables contained
in ISO 9770:1989, of which Table 1 is an extract.
10.11 If a vertical cylindrical tank is completely calibrated by the liquid calibration method, corrections for the
hydrostatic effect of the liquid (liquid head correction) due to changes in dimension of the tank are automatically
included in the final tank capacity tables, but only for liquids having similar densities to that of the calibration liquid
used. If the liquid which the tank is to hold in operation differs significantly in density from that of the calibration
liquid, correction for the effects of liquid head is required. Liquid head corrections shall be calculated in accordance
with ISO 7507-1.
10.12 If a vertical cylindrical tank is partly calibrated by liquid filling and partly by some other method, a correction
for liquid head may be required when the tank capacity table is calculated. Liquid head corrections shall be
calculated in accordance with ISO 7507-1.
10 © ISO 2001 – All rights reserved
Table 1 — Compressibility of liquid hydrocarbons — Percent change in volume per 100 kPa pressure
Density at 15 °C Temperature
�C
kg/m
–15 0 15 30
900 0,005 3 % 0,005 8 % 0,006 3 % 0,006 8 %
850 0,006 0 % 0,006 6 % 0,007 2 % 0,007 9 %
800 0,007 0 % 0,007 7 % 0,008 6 % 0,009 5 %
750 0,008 3 % 0,009 3 % 0,010 % 0,012 %
Annex A
(normative)
Correction for thermal effects
A.1 Volume correction factors
A.1.1 Calibration using water as a calibration liquid
Thecorrectionfactor, C , to be applied for the correction of the effects of temperature differences of the liquid between
fw
the meter and the tank being calibrated, when using water as a calibration liquid, are based on the ratio of the density
of fresh water at the two measured temperatures.
Thecorrectionfactor, C , is obtained from the following equation:
fw
�
t1
= (A.1)
C
fw
�
t2
where
� is the density of the water at the temperature of the water at the meter (t );
t1
� is the density of the water at the temperature of the water in the tank under calibration (t ).
t2
NOTE 1 C is the correction factor for temperature difference between the water in the meter and the water in the tank being
fw
calibrated; this correction factor does not correct the volume to 15 �Cor 20 �C.
The following equation shall be used for determining the density of pure, air-free water, � , in kilograms per cubic
t
metre, at temperature t of between 1 �C and 40 �C (see note 2).
23 45
��
����1 At�t�Btt� �Ct�t �Dtt� �Et�t (A.2)
�� � � �� �� � �
t00 0 0 0 0
� �
��
��
where
� is the density of water, in kilograms per cubic metre;
t
� is the density of water at temperature t ;
0 0
t is the temperature (3,981 8 �C) at which water attains its maximum density;
t is the temperature of the fluid, in degrees Celsius;
–8 –1
A is a polynomial coefficient, and equals 7,013 4 � 10 �C ;
–6 –2
B is a polynomial coefficient, and equals 7,926 504 � 10 �C ;
–8 –3
C is a polynomial coefficient, and equals – 7,575 677 � 10 �C ;
–10 –4
D is a polynomial coefficient, and equals 7,314 894 � 10 �C ;
–12 –5
E is a polynomial coefficient, and equals – 3,596 458 � 10 �C ;
The result of the equation shall be rounded to three decimal places.
12 © ISO 2001 – All rights reserved
NOTE 2 Values for the density of water are based on reference [8]. The equation is valid over the temperature range 1,0 �C
to 40 �C as measured on the International Temperature Scale of 1990, ITS-90.
If the water used in the calibration is air-saturated, a correction to the water density calculated by equation (A.2)
shall be applied, before rounding, by means of the following equation:
�33
Correction�� 4,612� 0,10t �10 kg/m (A.3)
��
w
where t is the temperature of the water.
w
The corrected water density shall be rounded to four decimal places.
NOTE 3 Equation (A.3) was derived [9] for water in the temperature range 0 �Cto 25 �C. For the purpose of this International
Standard, it is applied at water temperatures of up to 40 �C. Any error in tank calibration arising from using the equation in the
extended temperature range may be significant.
Table A.1 — Density of air-free water in kilograms per cubic metre against temperature in degrees Celsius
on the International Temperature Scale 1990 (P&M Equation)
Temp. Air
0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9
�C correction
1 999,9012 999,9061 999,9108 999,9153 999,9196 999,9237 999,9277 999,9316 999,9352 999,9387 – 0,0045
2 999,9420 999,9451 999,9481 999,9509 999,9536 999,9560 999,9583 999,9605 999,9625 999,9643 – 0,0043
3 999,9659 999,9674 999,9688 999,9699 999,9709 999,9718 999,9724 999,9730 999,9733 999,9735 – 0,0042
4 999,9736 999,9735 999,9732 999,9728 999,9722 999,9714 999,9705 999,9695 999,9683 999,9669 – 0,0041
5 999,9654 999,9637 999,9619 999,9599 999,9578 999,9555 999,9530 999,9504 999,9477 999,9448 – 0,0040
6 999,9418 999,9386 999,9352 999,9317 999,9281 999,9243 999,9204 999,9163 999,9121 999,9077 – 0,0039
7 999,9032 999,8985 999,8937 999,8888 999,8837 999,8784 999,8730 999,8675 999,8618 999,8560 – 0,0038
8 999,8500 999,8439 999,8377 999,8313 999,8248 999,8181 999,8113 999,8044 999,7973 999,7901 – 0,0037
9 999,7827 999,7753 999,7676 999,7599 999,7519 999,7439 999,7357 999,7274 999,7190 999,7104 – 0,0036
10 999,7017 999,6928 999,6838 999,6747 999,6654 999,6561 999,6465 999,6369 999,6271 999,6172 – 0,0035
11 999,6072 999,5970 999,5867 999,5762 999,5657 999,5550 999,5442 999,5332 999,5221 999,5109 – 0,0034
12 999,4996 999,4881 999,4765 999,4648 999,4530 999,4410 999,4289 999,4167 999,4043 999,3919 – 0,0033
13 999,3793 999,3665 999,3537 999,3407 999,3276 999,3144 999,3011 999,2876 999,2740 999,2603 – 0,0032
14 999,2465 999,2326 999,2185 999,2043 999,1900 999,1756 999,1611 999,1464 999,1316 999,1167 – 0,0031
15 999,1017 999,0865 999,0713 999,0559 999,0404 999,0248 999,0091 998,9932 998,9773 998,9612 – 0,0030
16 998,9450 998,9287 998,9123 998,8958 998,8791 998,8624 998,8455 998,8285 998,8114 998,7942 – 0,0029
17 998,7768 998,7594 998,7418 998,7242 998,7064 998,6885 998,6705 998,6524 998,6342 998,6158 – 0,0028
18 998,5974 998,5788 998,5602 998,5414 998,5225 998,5035 998,4844 998,4652 998,4459 998,4265 – 0,0027
19 998,4069 998,3873 998,3675 998,3477 998,3277 998,3076 998,2875 998,2672 998,2468 998,2263 – 0,0025
20 998,2057 998,1850 998,1642 998,1433 998,1222 998,1011 998,0799 998,0586 998,0371 998,0156 – 0,0024
21 997,9939 997,9722 997,9503 997,9284 997,9063 997,8842 997,8619 997,8396 997,8171 997,7945 – 0,0023
22 997,7719 997,7491 997,7262 997,7033 997,6802 997,6570 997,6338 997,6104 997,5870 997,5634 – 0,0022
23 997,5397 997,5160 997,4921 997,4681 997,4441 997,4199 997,3957 997,3713 997,3469 997,3223 – 0,0021
24 997,2977 997,2729 997,2481 997,2232 997,1981 997,1730 997,1478 997,1225 997,0971 997,0715 – 0,0020
25 997,0459 997,0202 996,9944 996,9686 996,9426 996,9165 996,8903 996,8641 996,8377 996,8112 – 0,0019
26 996,7847 996,7581 996,7313 996,7045 996,6776 996,6506 996,6235 996,5963 996,5690 996,5416 – 0,0018
27 996,5141 996,4865 996,4589 996,4311 996,4033 996,3754 996,3474 996,3192 996,2910 996,2627 – 0,0017
28 996,2344 996,2059 996,1773 996,1487 996,1199 996,0911 996,0622 996,0332 996,0041 995,9749 – 0,0016
29 995,9456 995,9163 995,8868 995,8573 995,8276 995,7979 995,7681 995,7382 995,7082 995,6782 – 0,0015
30 995,6480 995,6178 995,5874 995,5570 995,5265 995,4959 995,4653 995,4345 995,4037 995,3727 – 0,0014
31 995,3417 995,3106 995,2794 995,2482 995,2168 995,1853 995,1538 995,1222 995,0905 995,0587 – 0,0013
32 995,0269 994,9949 994,9629 994,9307 994,8985 994,8663 994,8339 994,8014 994,7689 994,7363 – 0,0012
33 994,7036 994,6708 994,6379 994,6050 994,5719 994,5388 994,5056 994,4723 994,4390 994,4055 – 0,0011
34 994,3720 994,3384 994,3047 994,2709 994,2371 994,2031 994,1691 994,1350 994,1008 994,0666 – 0,0010
35 994,0322 993,9978 993,9633 993,9287 993,8941 993,8593 993,8245 993,7896 993,7546 993,7196 – 0,0008
36 993,6844 993,6492 993,6139 993,5785 993,5431 993,5075 993,4719 993,4362 993,4004 993,3646 – 0,0007
37 993,3287 993,2927 993,2566 993,2204 993,1842 993,1478 993,1115 993,0750 993,0384 993,0018 – 0,0006
38 992,9651 992,9283 992,8914 992,8545 992,8175 992,7804 992,7432 992,7060 992,6687 992,6313 – 0,0005
39 992,5938 992,5563 992,5186 992,4809 992,4431 992,4053 992,3674 992,3294 992,2913 992,2531 – 0,0004
40 992,2149 – 0,0004
NOTE Round values of water density from the table to three decimal places.
14 © ISO 2001 – All rights reserved
A.1.2 Calibration using a suitable petroleum product as a calibration liquid
The correction factors to be applied for the correction of the effects of temperature differences of the liquid between the
meter and the tank being calibrated, when using a suitable petroleum product as a calibration liquid, are based on the
ratio of the density of product at the two measured temperatures.
However, the correction factor is most simply obtained from Table 54B of ISO 91-1:1992 or ISO 91-2:1991. A VCF for
the density at 15 °Cor20 °C, dependent on the standard reference temperature in use, and measured temperature, at
the meter, of the petroleum product is obtained and a second VCF at the temperature measured in the tank.
Application of the first VCF to the volume measured by the meter, after application of the meter factor, will correct the
volume measured by the meter to a volume at 15 °Cor20 °C. Division of this volume by the second VCF will correct
the measured volume to that in the tank at the temperature measured
...
SLOVENSKI STANDARD
01-februar-2006
Nafta in tekoči naftni proizvodi – Umerjanje rezervoarjev s tekočim merjenjem –
Postopna metoda z uporabo volumetrov
Petroleum and liquid petroleum products -- Tank calibration by liquid measurement --
Incremental method using volumetric meters
Pétrole et produits pétroliers liquides -- Jaugeage des réservoirs par épalement --
Méthode par empotement utilisant des compteurs volumétriques
Ta slovenski standard je istoveten z: ISO 4269:2001
ICS:
75.180.30 Oprema za merjenje Volumetric equipment and
prostornine in merjenje measurements
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
INTERNATIONAL ISO
STANDARD 4269
First edition
2001-03-15
Petroleum and liquid petroleum products —
Tank calibration by liquid measurement —
Incremental method using volumetric
meters
Pétrole et produits pétroliers liquides — Jaugeage des réservoirs par
épalement — Méthode par empotement utilisant des compteurs
volumétriques
Reference number
©
ISO 2001
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ii © ISO 2001 – All rights reserved
Contents Page
Foreword.iv
Introduction.v
1 Scope .1
2 Normative references .1
3 Terms and definitions .2
4 Precautions .2
5 Meters .2
6 Apparatus .4
7 Calibration procedure .5
8 Corrections to observed volumes.8
9 Calculation of tank capacity tables.9
10 Requirements for calculations .10
Annex A (normative) Correction for thermal effects .12
Annex B (informative) Field data and calculation sheets.18
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 4269 was prepared by Technical Committee ISO/TC 28, Petroleum products and
lubricants, Subcommittee SC 3, Static petroleum measurement.
Annex A forms a normative part of this International Standard. Annex B is for information only.
iv © ISO 2001 – All rights reserved
Introduction
This International Standard forms part of a series on tank calibration including the following:
ISO 7507-1, ISO 7507-2, ISO 7507-3, ISO 7507-4, ISO 7507-5, ISO 7507-6, ISO 8311, ISO 9091-1 and
ISO 9091-2.
Liquid calibration methods may be used in the calibration of either the total or partial capacity of a tank. A high degree
of accuracy may be obtained provided that great care is taken at all stages of the operation. The method is particularly
useful where tanks are of irregular shape, for the calibration of the bottom of any storage tank, or for the calibration of
ship and barge tanks having irregular cross sections.
The method offers a degree of accuracy which may exceed other methods when used in the calibration of small tanks,
especially small horizontal cylindrical tanks.
The calibration liquid may be either water or a suitable petroleum product having a low volatility and viscosity. Water is
recommended where wide temperature variations are expected during calibration as water has a low coefficient of
cubical expansion. However, the use of water may introduce unacceptable risks and difficulties depending on the use
to which the tank being calibrated is to be put (e.g. the use and subsequent removal of water when used in the
calibration of underground storage tanks at retail sites). In such circumstances the use of a suitable petroleum product
would be preferable.
INTERNATIONAL STANDARD ISO 4269:2001(E)
Petroleum and liquid petroleum products — Tank calibration by
liquid measurement — Incremental method using volumetric
meters
1 Scope
This International Standard specifies a method for the calibration of tanks by addition of batches of liquid. The liquid is
used as a volume-transfer medium, measured accurately by means of a meter.
This International Standard is not applicable to the calibration of reference measuring instruments, proving tanks, or
meter provers.
NOTE Applicable standards are given in the bibliography.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 91-1:1992, Petroleum measurement tables — Part 1: Tables based on references temperature of 15 °C and
60 °F.
ISO 91-2:1991, Petroleum measurement tables — Part 2: Tables based on a reference temperature of 20 °C.
ISO 2714:1980, Liquid hydrocarbons — Volumetric measurement by displacement meter systems other than
dispensing pumps.
ISO 2715:1981, Liquid hydrocarbons — Volumetric measurement by turbine meter systems.
ISO 4268, Petroleum and liquid petroleum products —Temperature measurements — Manual methods.
ISO 7507-1:1993, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks — Part 1:
Strapping method.
ISO/TR 7507-6:1997, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks — Part 6:
Recommendations for monitoring, checking and verification of tank calibration and capacity tables.
ISO 9770:1989, Crude petroleum and petroleum products — Compressibility factors for hydrocarbons in the range
3 3
638 kg/m to 1074 kg/m .
IEC 60079-10, Electrical apparatus for explosive gas atmospheres — Part 10: Classification of hazardous areas.
3 Terms and definitions
For the purposes of this International Standard, the terms and definitions given in ISO 7507-1, and the following, apply.
3.1
K-factor
number of pulses generated by a meter per unit of volume passing through it
3.2
pre-set device
equipment which shuts off the delivery of calibration liquid to the meter after a predetermined volume has passed
through the meter
4 Precautions
4.1 The general precautions and safety precautions in ISO 7507-1 and IEC 60079-10 shall apply to this
International Standard.
4.2 When a petroleum product is used as the calibration liquid, the following additional safety precautions, which
are not exhaustive, shall be observed:
a) control of sources of ignition;
b) prevention of electrostatic accumulation by
1) the correct bonding of transfer hoses,
2) control of pumping speeds,
3) prevention of free fall and splashing of liquid,
–
4) maintenance of the velocity of the liquid in the line below 1 ms until the end of the filling pipe is submerged.
5 Meters
5.1 General specifications
5.1.1 The meter shall be of the positive displacement or turbine type.
5.1.2 The meter shall be fabricated from materials suitable for the calibration liquid to be used.
5.1.3 The meter shall be selected so that the flow rate, at which the meter will operate during the tank calibration,
is within the linear range of the meter factor curve of the meter.
The meter should either be fitted with a flow-rate indicator, or average flow rates should be calculated by timing
deliveries by means of a stop watch.
5.1.4 The meter shall have either a device giving a read-out in volumetric units or an electronic pulse counter
used to calculate volume.
To enable the required repeatability to be determined during the proving of the meter, and depending on the
volume passed by the meter during such proving, a special counter or other indicator capable of being read to a
fraction of the unit of volume should be provided.
2 © ISO 2001 – All rights reserved
5.1.5 A volumetric proving tank, a pipe prover or a small volume prover, suitable for use with the type of meter
chosen, shall be provided for calibrating the meter. The selected apparatus shall be provided with a calibration
certificate showing any corrections which may be required when in use.
5.1.6 A thermowell (thermometer pocket) shall be provided in the metering system adjacent to the meter.
To ensure adequate immersion and thermal response, and to avoid undesirable thermal conduction effects from
the pipe wall, it is recommended that, particularly in the case of small diameter lines, the pocket should be installed
in the body of the meter if a positive displacement meter is used. If a turbine meter is used, then the thermowell
shall be installed in the pipework at least five pipe diameters downstream of the meter position. The thermowell
should be in direct contact with the calibration liquid and should be filled with a light oil to aid thermal response. The
thermowell, and the fitting in which the sensitive element of the thermometer is immersed, should be designed in
accordance with sound thermo-technical principles. It may be desirable to provide external insulation round the
pipe or fitting at the position of, and adjacent to, the thermowell.
5.1.7 A rapid operating valve or shut off device shall be installed downstream of the meter (see 6.4.5).
5.2 Positive displacement meters
The meter factor shall not deviate by more than � 0,20 % from the average meter factor between 10 % and 100 % of
the maximum rated flow rate of the meter.
5.3 Turbine meters
5.3.1 The K-factor shall not deviate by more than � 0,20 % between 10 % and 100 % of the maximum capacity
of the meter.
5.3.2 A back pressure in excess of 100 kPa (gauge) shall be applied in order to prevent cavitation.
5.4 Selection of meter
5.4.1 The selection of a meter for tank calibration is contingent on the following:
a) the operating rate of flow to be used when calibrating the tank (see 5.4.4);
b) the maximum pressure to which the meter will be subjected;
c) the liquid which the meter is required to measure (see 5.1.2);
d) the temperature range over which the meter will operate;
e) the range of viscosities over which the meter will operate.
5.4.2 Meters incorporating a temperature compensator shall not be used for tank calibration.
5.4.3 The meter shall be provided with a meter factor or K-factor curve (error–flow curve) for the type of liquid,
viscosity, temperature and range of flow rates over which it will be used.
5.4.4 The repeatability of the meter shall be such that the results of five consecutive proving runs shall be within
arangeof � 0,025 % of the average after correcting for temperature, pressure and viscosity.
5.4.5 Meters shall be installed and operated in accordance with the appropriate recommendations contained in
ISO 2714 or ISO 2715.
6 Apparatus
6.1 Dip-tape and dip-weight
This shall be as specified in ISO 7507-1:1993, B.6 and B.7.
6.2 Ullage paste
NOTE The term "oil-finding paste" is synonymous.
6.3 Water-finding paste
6.4 Ancillary equipment
6.4.1 Air/vapour separator
An air separator, when utilized, shall be fitted upstream of the meter.
A back-pressure valve may be required to maintain an adequate pressure drop across the air release valve fitted to
the air separator.
6.4.2 Flow limiter
A flow limiting device shall be fitted in the line, downstream of the meter, to limit the rate of flow if the pressure of the
calibration liquid supply is such that the flow rate through the installation is too great for the rated capacity of the meter.
6.4.3 Pre-set device
The pre-set device should be leak proof and operate quickly with a smooth action, without causing any undue
pressure surge.
6.4.4 Pressure gauge
Where a positive displacement meter is used, a pressure gauge shall be mounted in the line as close to the meter as
possible, preferably on the downstream side. Where a turbine meter is used, a pressure gauge shall be installed at
least five pipe diameters downstream from the meter. It may be preferable that two pressure gauges are installed
equidistant from the meter upstream and downstream
6.4.5 Shut-off valve
The valve shall be leak proof, and shall operate quickly with a smooth action and without causing an undue pressure
surge.
If a pre-set device is not fitted, a shut-off valve, to shut off the flow at the required intervals, shall be installed
downstream of the meter.
6.4.6 Strainer
6.4.7 Surge suppressor
If surge pressures are likely to occur, a suitable surge suppressor should be fitted to the line.
6.4.8 Syphon breaker
If fitted, the syphon breaker shall be downstream of the meter as close to the delivery point as is possible.
When a tank is being calibrated by top filling, then the syphon breaker should be installed in conjunction with a
weir. The assembly should be fitted at the highest point in the system.
4 © ISO 2001 – All rights reserved
6.4.9 Viewing glass
A viewing glass shall be provided adjacent to/in the air separator if utilized.
6.4.10 Weir
If installed, the weir shall be positioned in such a way as to ensure that the delivery pipe downstream of the meter is full
at all times.
7 Calibration procedure
7.1 General requirements
7.1.1 A tank shall only be calibrated after it has been filled at least once with a liquid of density equal to or
greater than that which it will hold when in use.
NOTE The hydrostatic test applied to new or repaired tanks will satisfy this requirement in most cases.
7.1.2 Before commencing calibration, the system shall be checked for leakage downstream of the meter. Any
leaks found shall be eliminated.
7.1.3 The serial numbers, or identification marks, of thermometers used in the course of calibration shall be
recorded together with their location during the calibration. The thermometers shall be calibrated in accordance
with ISO 4268 and shall be provided with a certificate showing corrections.
7.1.4 Care shall be exercised to avoid the ingress of air into the system when using a meter to calibrate a tank.
It is important that the meter, ancillary equipment and lines be liquid filled before the commencement of calibration.
7.1.5 If fitted, a strainer/filter shall be installed in the line upstream of the meter to protect the meter from
abrasion or other damage from entrained foreign matter.
7.1.6 If the variation of the volume of calibration liquid in the hose connecting the meter to the tank, compared
with the total volume of liquid in the tank, is such that the accuracy of the calibration would be significantly affected,
a syphon breaker shall be placed at the end of the hose to ensure that the hose remains filled with a constant
quantity of liquid.
7.1.7 Excessive variations in the temperature of the calibration liquid shall be avoided if the required accuracy is
to be maintained.
Large fluctuations make it difficult to determine an accurate mean temperature and this in turn causes the following:
a) uncertainties in applying the volume correction factors to the liquid;
b) uncertainties in applying the correction factor for the expansion/ contraction of the measuring equipment;
c) uncertainties in applying the correction factor for the expansion/ contraction of the tank being calibrated.
7.1.8 An adequate supply of the calibration liquid shall be available. The pressure available shall be sufficient, at
all times, to maintain stable flow rates within the normal operating range of the meter.
7.1.9 If a petroleum product is used as the calibration liquid, its depth in the tank shall be measured with product-
finding paste applied in a smooth even film to the dip-tape and dip-weight.
7.1.10 If water is used as the calibration liquid, its depth in the tank shall be measured with water-finding paste
applied in a smooth even film to the dip-tape and dip-weight.
7.1.11 The exact height of the upper reference point above the dip-point shall be determined at the time of
calibration. The overall dipping height shall be marked on the roof of the tank at or near to the dip hatch to which it
applies.
In tanks with a single dip point, the upper reference point shall be clearly marked on the tank and its height above the
dipping datum point shall be recorded at the head of the table. In tanks with more than one dip point, the overall height
at each dip point shall be clearly marked adjacent to the point. This measurement may require adjustment to correct for
the difference between the actual and the certified reference temperature of the dip-tape and dip-weight used to
measure the overall dipping height. The correction shall be calculated in accordance with the equation given in A.3.
7.1.12 If the calibration of the tank is interrupted, it may be resumed at a later date provided that
a) if there is a change of equipment or personnel, sufficient check measurements are made to ensure that the
results obtained prior to the changes correspond within the tolerances laid down in this method,
b) all records of work previously carried out are complete and legible, and
c) the new liquid mean temperature and depth at resumption of operations are recorded.
7.2 Equipment
The calibration of a tank may not necessarily require all of the equipment listed in clause 6. The requirements for each
operation shall be considered before selecting equipment.
7.3 Installation
7.3.1 Figure 1 shows a schematic diagram of a typical installation for calibration by meter.
7.3.2 Attention shall be paid to pipework to ensure minimum pressure drop and turbulence.
Any condition which tends to increase the turbulence of the liquid stream should be avoided.
7.3.3 The meter shall be installed in such a manner that no undue strain is imposed upon it due to the mass or
thermal expansion/contraction of the pipework.
7.3.4 Flexible hoses may be used to provide a supply of liquid for calibration purposes. If they are used on the
downstream side, the total length shall be kept to a minimum.
7.4 Meter proving
7.4.1 The meter shall be proved, on site, using either a volumetric prover tank, meter or pipe prover.
Proving should preferably be carried out using the same fluid as that in the tank.
7.4.2 Proving shall be carried out, as a minimum, immediately prior to commencement and on completion of any
calibration. If the calibration process extends over more than one day, the meter shall be proved at commencement
of calibration and on completion of calibration on each day. Proving may be carried out at shorter intervals to
ensure that the meter or K-factor has not drifted.
NOTE Proving at a central proving station/installation may be acceptable if meters are proved under conditions which
closely replicate those encountered at the calibration site.
6 © ISO 2001 – All rights reserved
Key
1 Tank to be calibrated
2 Flow limiter
3 Non-return valve
4 Thermometer
5 Pressure gauge
6 Air/vapour separator
7 Strainer
8 Supply
9 Meter
10 Syphon breaker
a
To air/vapour separator.
b
To vent.
Figure 1 — Schematic diagram of a typical installation for calibration by meter
7.5 Calibration procedure
7.5.1 The calibration liquid shall be transferred into the tank at a flow rate for which the meter has been
calibrated and at such a rate as to minimize disturbance of the liquid surface in the tank.
Care should be taken during the initial filling of the system to avoid over-ranging of the meter when the air in the
system is being displaced. If flow rates are likely to exceed the rated capacity of the meter, a suitable flow control
valve should be fitted downstream of the meter (see 6.4.2).
7.5.2 The calibration liquid shall be added in incremental volumes sufficient to produce a significant change in
the liquid level with reference to the section of the tank being calibrated, and having due regard to the uncertainty
of liquid level gauging.
NOTE During calibration, the increase in the liquid level is dependent on the size of the liquid volumes introduced into the
tank; i.e. the liquid level is the dependent variable. In a capacity table, the liquid level is the independent variable; the calculation
of the table from field measurements is dependent on the size of the increments added to the tank and to the interpolation
techniques used to calculate the capacity table. Care should be exercised to ensure that the incremental volumes added to the
tank during calibration are of a size which ensures a significant movement in the liquid level but are small enough to minimize
the uncertainty arising from the interpolation technique used in calculating the capacity table.
7.5.3 After the addition of each increment, the liquid surface shall be allowed to settle and the liquid depth
measured at the dip-point by use of a dip-tape and dip-weight.
Liquid depth measurements shall be made and recorded to the nearest millimetre. The depth measurement shall be
taken and shall be repeated. The two measurements shall agree to within 1 mm. If the readings differ from each other
by more than 1 mm, then the depth measurements shall be repeated until two consecutive readings are within the
tolerance limit.
NOTE If ripples on the surface give rise to difficulties in making measurements, a ripple damping device may be used.
7.5.4 After each increase in depth has been measured and recorded, the temperature of the liquid at the meter,
using the thermowell (see 5.1.6) and in the tank shall be taken to the nearest 0,25 °C or better.
NOTE The number of temperature readings may be reduced to one in every five increments if the temperature is found to
be constant.
7.5.5 The ambient air temperature in close proximity to the tank being calibrated shall be measured to the
nearest 0,25 °C, or better, at intervals throughout the calibration period. The recorded temperatures shall be taken
at intervals of time which will accurately reflect the ambient air temperature throughout the calibration process.
7.5.6 If a petroleum product is being used as a calibration liquid, then the pressure on the liquid at the meter
shall be measured and recorded at intervals through out the calibration period. The recorded pressures shall be
taken at intervals of time which will accurately reflect the pressures exerted on the liquid throughout the calibration
process.
7.5.7 If the volume displaced by the inlet hose, compared to the total volume of liquid in the tank, is such that the
accuracy of the calibration would be significantly affected, the inlet hose shall be withdrawn until its lower end is
above the level of the liquid in the tank. Special care and attention shall be exercised to obtain the same amount of
draining before measurements are made of the liquid depth; the liquid surface shall be quiescent.
8 Corrections to observed volumes
8.1 General
Corrections to the observed volumes are required for one or more of the following:
a) calibration error of the meter used;
b) effect of temperature variations on the meter used;
c) effect of temperature variations on the calibration liquid used;
d) effect of temperature variations on the tank being calibrated;
e) effect of temperature variations on the dip-tape and dip-weight used.
If necessary, these corrections shall be calculated and applied when computing a tank capacity table. The tank
calibrator shall ensure that all necessary details for the calculation of the corrections are included in the calibration
notes.
8.2 Meter factor and K-factor
8.2.1 The meter factor or K-factor for the meter in use shall be the average of the factors calculated at the
commencement and completion of the calibration.
8.2.2 The meter factor or K-factor at the commencement and completion of the calibration shall not differ by
more than 0,05 %. If the two factors differ by more than 0,1 % then the reason for the difference shall be
determined and, if necessary, the calibration shall be repeated.
8 © ISO 2001 – All rights reserved
8.3 Temperature changes in the calibration liquid
8.3.1 A correction shall be made for any change in the temperature of the calibration liquid between the time that
it is measured in the meter and the time that it is measured in the tank being calibrated.
8.3.2 If the calibration liquid used is a petroleum product and the tank calibration table is required to be correct at
either 15 °Cor 20 °C, the volume delivered shall be corrected for temperature changes in the calibration liquid by
using the Volume Correction Factor (VCF) table for petroleum products in ISO 91-1:1992 or ISO 91-2:1991
respectively.
8.3.3 If the calibration liquid used is water and the tank calibration table is required to be correct at 15 °C, the
volume delivered shall be corrected for temperature changes in the calibration liquid by using the table of water
densities or the formula given in annex A.
8.3.4 The corrections shall be made in the following order:
a) correction of the observed calibration liquid temperature to reference temperature;
b) correction of the capacity of the container shell for thermal effects;
c) correction of the liquid level measurement/dip-tape and dip-weight for thermal effects.
8.4 Temperature changes in the tank shell
A correction for the difference in temperature between the shell of the tank at the time of calibration and its average
temperature in service, or between the temperature at calibration and a standard reference temperature, e.g. 15 °C,
shall be made according to the method given in annex A. The tank shell temperature shall be determined by one of the
methods given in annex A of either ISO 7507-1:1993 or ISO 7507-6:1997.
8.5 Temperature effects on dip-tapes and other measures of length
Dip-tapes and other measures of length are calibrated at 20 °C but if they are used at other temperatures, within the
range 20 °C � 5 °C, the corrections for temperature changes are small (of the order of 1 mm in 18 m) and may be
neglected in all cases. Outside this range, a correction is required (see A.3).
8.6 Method of correcting for temperature effects
8.6.1 When the total capacity of the tank has been calibrated by meter and the tank capacity table is required to
be at a reference temperature of either 15 °Cor20 °C the corrections in 8.4 to 8.5 may be conveniently combined.
8.6.2 If calibration is required to be correct at some other temperature, the adjustment to the standard
temperature shall first be made and a further correction calculated for the thermal expansion or contraction of the
tank shell shall be in accordance with annex A.
9 Calculation of tank capacity tables
9.1 All calculations shall be made in accordance with accepted mathematical principles.
Errors in calculation are minimized and checking facilitated by the adoption of a standard form of data and
calculation sheet. The use of the forms illustrated in annex B is recommended for site data collection and for
calculation.
9.2 Tank capacity tables
9.2.1 Provided that tank capacity tables have been calculated in accordance with the principles given in this part
of ISO 4269, the format adopted will not affect the mathematical correctness of the table. However, the principles
laid down in this clause are recommended since they provide a table in a form most convenient for use. Each tank
calibrated in accordance with this part of ISO 4269 shall be issued with a certificate of calibration as specified in
ISO 7507-1:1993, annex E.
9.2.2 At the head of each tank calibration table it shall be clearly stated the method by which the liquid level for
entry to the tank capacity table shall be determined.
9.2.3 Table headings shall show the tank reference number and location, the temperature at which the table is
correct, and the date of calibration.
9.2.4 The intervals of dip at which the table is set out shall be chosen so as to allow linear interpolation for
intermediate dips without significant loss of accuracy.
10 Requirements for calculations
10.1 All readings of instruments shall be recorded as observed, without correction for errors which shall be shown
separately. Recorded figures shall be checked for consistency before proceeding to the next entry. In all cases of
doubt, the readings shall be verified.
10.2 Temperature shall be recorded to at least the nearest 0,25 °C.
10.3 Volumetric readings shall be recorded to the nearest graduation on the meter registers.
10.4 All correction factors obtained from tables shall be used without rounding.
10.5 Other correction factors which require to be calculated shall be correct to 5 significant figures.
10.6 All calculations shall be carried out to be correct to at least 5 significant figures.
10.7 Depth measurements which shall be recorded to the nearest 1 mm, and shall be shown corrected to the
nearest 1 mm.
10.8 The final tables shall be calculated by interpolation from the corrected cumulative volumes.
10.9 Final volumes in tank capacity tables obtained by interpolation shall be rounded off to the nearest whole litre
and shown against the required tabular interval of dip or ullage.
10.10 If a petroleum product is being used as a calibration liquid, then the pressure on the liquid shall have been
measured and recorded at intervals throughout the calibration period. If required, a correction for the
compressibility of the liquid used may be calculated using either a factor from Table 1 or from the tables contained
in ISO 9770:1989, of which Table 1 is an extract.
10.11 If a vertical cylindrical tank is completely calibrated by the liquid calibration method, corrections for the
hydrostatic effect of the liquid (liquid head correction) due to changes in dimension of the tank are automatically
included in the final tank capacity tables, but only for liquids having similar densities to that of the calibration liquid
used. If the liquid which the tank is to hold in operation differs significantly in density from that of the calibration
liquid, correction for the effects of liquid head is required. Liquid head corrections shall be calculated in accordance
with ISO 7507-1.
10.12 If a vertical cylindrical tank is partly calibrated by liquid filling and partly by some other method, a correction
for liquid head may be required when the tank capacity table is calculated. Liquid head corrections shall be
calculated in accordance with ISO 7507-1.
10 © ISO 2001 – All rights reserved
Table 1 — Compressibility of liquid hydrocarbons — Percent change in volume per 100 kPa pressure
Density at 15 °C Temperature
�C
kg/m
–15 0 15 30
900 0,005 3 % 0,005 8 % 0,006 3 % 0,006 8 %
850 0,006 0 % 0,006 6 % 0,007 2 % 0,007 9 %
800 0,007 0 % 0,007 7 % 0,008 6 % 0,009 5 %
750 0,008 3 % 0,009 3 % 0,010 % 0,012 %
Annex A
(normative)
Correction for thermal effects
A.1 Volume correction factors
A.1.1 Calibration using water as a calibration liquid
Thecorrectionfactor, C , to be applied for the correction of the effects of temperature differences of the liquid between
fw
the meter and the tank being calibrated, when using water as a calibration liquid, are based on the ratio of the density
of fresh water at the two measured temperatures.
Thecorrectionfactor, C , is obtained from the following equation:
fw
�
t1
= (A.1)
C
fw
�
t2
where
� is the density of the water at the temperature of the water at the meter (t );
t1
� is the density of the water at the temperature of the water in the tank under calibration (t ).
t2
NOTE 1 C is the correction factor for temperature difference between the water in the meter and the water in the tank being
fw
calibrated; this correction factor does not correct the volume to 15 �Cor 20 �C.
The following equation shall be used for determining the density of pure, air-free water, � , in kilograms per cubic
t
metre, at temperature t of between 1 �C and 40 �C (see note 2).
23 45
��
����1 At�t�Btt� �Ct�t �Dtt� �Et�t (A.2)
�� � � �� �� � �
t00 0 0 0 0
� �
��
��
where
� is the density of water, in kilograms per cubic metre;
t
� is the density of water at temperature t ;
0 0
t is the temperature (3,981 8 �C) at which water attains its maximum density;
t is the temperature of the fluid, in degrees Celsius;
–8 –1
A is a polynomial coefficient, and equals 7,013 4 � 10 �C ;
–6 –2
B is a polynomial coefficient, and equals 7,926 504 � 10 �C ;
–8 –3
C is a polynomial coefficient, and equals – 7,575 677 � 10 �C ;
–10 –4
D is a polynomial coefficient, and equals 7,314 894 � 10 �C ;
–12 –5
E is a polynomial coefficient, and equals – 3,596 458 � 10 �C ;
The result of the equation shall be rounded to three decimal places.
12 © ISO 2001 – All rights reserved
NOTE 2 Values for the density of water are based on reference [8]. The equation is valid over the temperature range 1,0 �C
to 40 �C as measured on the International Temperature Scale of 1990, ITS-90.
If the water used in the calibration is air-saturated, a correction to the water density calculated by equation (A.2)
shall be applied, before rounding, by means of the following equation:
�33
Correction�� 4,612� 0,10t �10 kg/m (A.3)
��
w
where t is the temperature of the water.
w
The corrected water density shall be rounded to four decimal places.
NOTE 3 Equation (A.3) was derived [9] for water in the temperature range 0 �Cto 25 �C. For the purpose of this International
Standard, it is applied at water temperatures of up to 40 �C. Any error in tank calibration arising from using the equation in the
extended temperature range may be significant.
Table A.1 — Density of air-free water in kilograms per cubic metre against temperature in degrees Celsius
on the International Temperature Scale 1990 (P&M Equation)
Temp. Air
0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9
�C correction
1 999,9012 999,9061 999,9108 999,9153 999,9196 999,9237 999,9277 999,9316 999,9352 999,9387 – 0,0045
2 999,9420 999,9451 999,9481 999,9509 999,9536 999,9560 999,9583 999,9605 999,9625 999,9643 – 0,0043
3 999,9659 999,9674 999,9688 999,9699 999,9709 999,9718 999,9724 999,9730 999,9733 999,9735 – 0,0042
4 999,9736 999,9735 999,9732 999,9728 999,9722 999,9714 999,9705 999,9695 999,9683 999,9669 – 0,0041
5 999,9654 999,9637 999,9619 999,9599 999,9578 999,9555 999,9530 999,9504 999,9477 999,9448 – 0,0040
6 999,9418 999,9386 999,9352 999,9317 999,9281 999,9243 999,9204 999,9163 999,9121 999,9077 – 0,0039
7 999,9032 999,8985 999,8937 999,8888 999,8837 999,8784 999,8730 999,8675 999,8618 999,8560 – 0,0038
8 999,8500 999,8439 999,8377 999,8313 999,8248 999,8181 999,8113 999,8044 999,7973 999,7901 – 0,0037
9 999,7827 999,7753 999,7676 999,7599 999,7519 999,7439 999,7357 999,7274 999,7190 999,7104 – 0,0036
10 999,7017 999,6928 999,6838 999,6747 999,6654 999,6561 999,6465 999,6369 999,6271 999,6172 – 0,0035
11 999,6072 999,5970 999,5867 999,5762 999,5657 999,5550 999,5442 999,5332 999,5221 999,5109 – 0,0034
12 999,4996 999,4881 999,4765 999,4648 999,4530 999,4410 999,4289 999,4167 999,4043 999,3919 – 0,0033
13 999,3793 999,3665 999,3537 999,3407 999,3276 999,3144 999,3011 999,2876 999,2740 999,2603 – 0,0032
14 999,2465 999,2326 999,2185 999,2043 999,1900 999,1756 999,1611 999,1464 999,1316 999,1167 – 0,0031
15 999,1017 999,0865 999,0713 999,0559 999,0404 999,0248 999,0091 998,9932 998,9773 998,9612 – 0,0030
16 998,9450 998,9287 998,9123 998,8958 998,8791 998,8624 998,8455 998,8285 998,8114 998,7942 – 0,0029
17 998,7768 998,7594 998,7418 998,7242 998,7064 998,6885 998,6705 998,6524 998,6342 998,6158 – 0,0028
18 998,5974 998,5788 998,5602 998,5414 998,5225 998,5035 998,4844 998,4652 998,4459 998,4265 – 0,0027
19 998,4069 998,3873 998,3675 998,3477 998,3277 998,3076 998,2875 998,2672 998,2468 998,2263 – 0,0025
20 998,2057 998,1850 998,1642 998,1433 998,1222 998,1011 998,0799 998,0586 998,0371 998,0156 – 0,0024
21 997,9939 997,9722 997,9503 997,9284 997,9063 997,8842 997,8619 997,8396 997,8171 997,7945 – 0,0023
22 997,7719 997,7491 997,7262 997,7033 997,6802 997,6570 997,6338 997,6104 997,5870 997,5634 – 0,0022
23 997,5397 997,5160 997,4921 997,4681 997,4441 997,4199 997,3957 997,3713 997,3469 997,3223 – 0,0021
24 997,2977 997,2729 997,2481 997,2232 997,1981 997,1730 997,1478 997,1225 997,0971 997,0715 – 0,0020
25 997,0459 997,0202 996,9944 996,9686 996,9426 996,9165 996,8903 996,8641 996,8377 996,8112 – 0,0019
26 996,7847 996,7581 996,7313 996,7045 996,6776 996,6506 996,6235 996,5963 996,5690 996,5416 – 0,0018
27 996,5141 996,4865 996,4589 996,4311 996,4033 996,3754 996,3474 996,3192 996,2910 996,2627 – 0,0017
28 996,2344 996,2059 996,1773 996,1487 996,1199 996,0911 996,0622 996,0332 996,0041 995,9749 – 0,0016
29 995,9456 995,9163 995,8868 995,8573 995,8276 995,7979 995,7681 995,7382 995,7082 995,6782 – 0,0015
30 995,6480 995,6178 995,5874 995,5570 995,5265 995,4959 995,4653 995,4345 995,4037 995,3727 – 0,0014
31 995,3417 995,3106 995,2794 995,2482 995,2168 995,1853 995,1538 995,1222 995,0905 995,0587 – 0,0013
32 995,0269 994,9949 994,9629 994,9307 994,8985 994,8663 994,8339 994,8014 994,7689 994,7363 – 0,0012
33 994,7036 994,6708 994,6379 994,6050 994,5719 994,5388 994,5056 994,4723 994,4390 994,4055 – 0,0011
34 994,3720 994,3384 994,3047 994,2709 994,2371 994,2031 994,1691 994,1350 994,1008 994,0666 – 0,0010
35 994,0322 993,9978 993,9633 993,9287 993,8941 993,8593 993,8245 993,7896 993,7546 993,7196 – 0,0008
36 993,6844 993,6492 993,6139 993,5785 993,5431 993,5075 993,4719 993,4362 993,4004 993,3646 – 0,0007
37 993,3287 993,2927 993,2566 993,2204 993,1842 993,1478 993,1115 993,0750 993,0384 993,0018 – 0,0006
38 992,9651 992,9283 992,8914 992,8545 992,8175 992,7804 992,7432 992,7060 992,6687 992,6313 – 0,0005
39 992,5938 992,5563 992,5186 992,4809 992,4431 992,4053 992,3674 992,3294 992,2913 992,2531 – 0,0004
40 992,2149 – 0,0004
NOTE Round values of water density from the table to three decimal places.
14 © ISO 2001 – All rights reserved
A.1.2 Calibration using a suitable petroleum product as a calibration liquid
The correction factors to be applied for the correction of the effects of temperature differences of the liquid between the
meter and the tank being calibrated, when using a suitable petroleum product as a calibration liquid, are based on the
ratio of the density of product at the two measured temperatures.
However, the correction factor is most simply obtained from Table 54B of ISO 91-1:1992 or ISO 91-2:1991. A VCF for
the density at 15 °Cor20 °C, dependent on the standard reference temperature in use, and measured temperature, at
the meter, of the petroleum product is obtained and a second VCF at the temperature measured in the tank.
Application of the first VCF to the volume measured by the meter, after application of the meter factor, will correct the
volume measured by the meter to a volume at 15 °Cor20 °C. Division of this volume by the second VCF will correct
the measured volume to that in the tank at the temperature measured in the tank.
NOTE 1 This calculation is s
...
INTERNATIONAL ISO
STANDARD 4269
First edition
2001-03-15
Petroleum and liquid petroleum products —
Tank calibration by liquid measurement —
Incremental method using volumetric
meters
Pétrole et produits pétroliers liquides — Jaugeage des réservoirs par
épalement — Méthode par empotement utilisant des compteurs
volumétriques
Reference number
©
ISO 2001
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ii © ISO 2001 – All rights reserved
Contents Page
Foreword.iv
Introduction.v
1 Scope .1
2 Normative references .1
3 Terms and definitions .2
4 Precautions .2
5 Meters .2
6 Apparatus .4
7 Calibration procedure .5
8 Corrections to observed volumes.8
9 Calculation of tank capacity tables.9
10 Requirements for calculations .10
Annex A (normative) Correction for thermal effects .12
Annex B (informative) Field data and calculation sheets.18
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 4269 was prepared by Technical Committee ISO/TC 28, Petroleum products and
lubricants, Subcommittee SC 3, Static petroleum measurement.
Annex A forms a normative part of this International Standard. Annex B is for information only.
iv © ISO 2001 – All rights reserved
Introduction
This International Standard forms part of a series on tank calibration including the following:
ISO 7507-1, ISO 7507-2, ISO 7507-3, ISO 7507-4, ISO 7507-5, ISO 7507-6, ISO 8311, ISO 9091-1 and
ISO 9091-2.
Liquid calibration methods may be used in the calibration of either the total or partial capacity of a tank. A high degree
of accuracy may be obtained provided that great care is taken at all stages of the operation. The method is particularly
useful where tanks are of irregular shape, for the calibration of the bottom of any storage tank, or for the calibration of
ship and barge tanks having irregular cross sections.
The method offers a degree of accuracy which may exceed other methods when used in the calibration of small tanks,
especially small horizontal cylindrical tanks.
The calibration liquid may be either water or a suitable petroleum product having a low volatility and viscosity. Water is
recommended where wide temperature variations are expected during calibration as water has a low coefficient of
cubical expansion. However, the use of water may introduce unacceptable risks and difficulties depending on the use
to which the tank being calibrated is to be put (e.g. the use and subsequent removal of water when used in the
calibration of underground storage tanks at retail sites). In such circumstances the use of a suitable petroleum product
would be preferable.
INTERNATIONAL STANDARD ISO 4269:2001(E)
Petroleum and liquid petroleum products — Tank calibration by
liquid measurement — Incremental method using volumetric
meters
1 Scope
This International Standard specifies a method for the calibration of tanks by addition of batches of liquid. The liquid is
used as a volume-transfer medium, measured accurately by means of a meter.
This International Standard is not applicable to the calibration of reference measuring instruments, proving tanks, or
meter provers.
NOTE Applicable standards are given in the bibliography.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 91-1:1992, Petroleum measurement tables — Part 1: Tables based on references temperature of 15 °C and
60 °F.
ISO 91-2:1991, Petroleum measurement tables — Part 2: Tables based on a reference temperature of 20 °C.
ISO 2714:1980, Liquid hydrocarbons — Volumetric measurement by displacement meter systems other than
dispensing pumps.
ISO 2715:1981, Liquid hydrocarbons — Volumetric measurement by turbine meter systems.
ISO 4268, Petroleum and liquid petroleum products —Temperature measurements — Manual methods.
ISO 7507-1:1993, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks — Part 1:
Strapping method.
ISO/TR 7507-6:1997, Petroleum and liquid petroleum products — Calibration of vertical cylindrical tanks — Part 6:
Recommendations for monitoring, checking and verification of tank calibration and capacity tables.
ISO 9770:1989, Crude petroleum and petroleum products — Compressibility factors for hydrocarbons in the range
3 3
638 kg/m to 1074 kg/m .
IEC 60079-10, Electrical apparatus for explosive gas atmospheres — Part 10: Classification of hazardous areas.
3 Terms and definitions
For the purposes of this International Standard, the terms and definitions given in ISO 7507-1, and the following, apply.
3.1
K-factor
number of pulses generated by a meter per unit of volume passing through it
3.2
pre-set device
equipment which shuts off the delivery of calibration liquid to the meter after a predetermined volume has passed
through the meter
4 Precautions
4.1 The general precautions and safety precautions in ISO 7507-1 and IEC 60079-10 shall apply to this
International Standard.
4.2 When a petroleum product is used as the calibration liquid, the following additional safety precautions, which
are not exhaustive, shall be observed:
a) control of sources of ignition;
b) prevention of electrostatic accumulation by
1) the correct bonding of transfer hoses,
2) control of pumping speeds,
3) prevention of free fall and splashing of liquid,
–
4) maintenance of the velocity of the liquid in the line below 1 ms until the end of the filling pipe is submerged.
5 Meters
5.1 General specifications
5.1.1 The meter shall be of the positive displacement or turbine type.
5.1.2 The meter shall be fabricated from materials suitable for the calibration liquid to be used.
5.1.3 The meter shall be selected so that the flow rate, at which the meter will operate during the tank calibration,
is within the linear range of the meter factor curve of the meter.
The meter should either be fitted with a flow-rate indicator, or average flow rates should be calculated by timing
deliveries by means of a stop watch.
5.1.4 The meter shall have either a device giving a read-out in volumetric units or an electronic pulse counter
used to calculate volume.
To enable the required repeatability to be determined during the proving of the meter, and depending on the
volume passed by the meter during such proving, a special counter or other indicator capable of being read to a
fraction of the unit of volume should be provided.
2 © ISO 2001 – All rights reserved
5.1.5 A volumetric proving tank, a pipe prover or a small volume prover, suitable for use with the type of meter
chosen, shall be provided for calibrating the meter. The selected apparatus shall be provided with a calibration
certificate showing any corrections which may be required when in use.
5.1.6 A thermowell (thermometer pocket) shall be provided in the metering system adjacent to the meter.
To ensure adequate immersion and thermal response, and to avoid undesirable thermal conduction effects from
the pipe wall, it is recommended that, particularly in the case of small diameter lines, the pocket should be installed
in the body of the meter if a positive displacement meter is used. If a turbine meter is used, then the thermowell
shall be installed in the pipework at least five pipe diameters downstream of the meter position. The thermowell
should be in direct contact with the calibration liquid and should be filled with a light oil to aid thermal response. The
thermowell, and the fitting in which the sensitive element of the thermometer is immersed, should be designed in
accordance with sound thermo-technical principles. It may be desirable to provide external insulation round the
pipe or fitting at the position of, and adjacent to, the thermowell.
5.1.7 A rapid operating valve or shut off device shall be installed downstream of the meter (see 6.4.5).
5.2 Positive displacement meters
The meter factor shall not deviate by more than � 0,20 % from the average meter factor between 10 % and 100 % of
the maximum rated flow rate of the meter.
5.3 Turbine meters
5.3.1 The K-factor shall not deviate by more than � 0,20 % between 10 % and 100 % of the maximum capacity
of the meter.
5.3.2 A back pressure in excess of 100 kPa (gauge) shall be applied in order to prevent cavitation.
5.4 Selection of meter
5.4.1 The selection of a meter for tank calibration is contingent on the following:
a) the operating rate of flow to be used when calibrating the tank (see 5.4.4);
b) the maximum pressure to which the meter will be subjected;
c) the liquid which the meter is required to measure (see 5.1.2);
d) the temperature range over which the meter will operate;
e) the range of viscosities over which the meter will operate.
5.4.2 Meters incorporating a temperature compensator shall not be used for tank calibration.
5.4.3 The meter shall be provided with a meter factor or K-factor curve (error–flow curve) for the type of liquid,
viscosity, temperature and range of flow rates over which it will be used.
5.4.4 The repeatability of the meter shall be such that the results of five consecutive proving runs shall be within
arangeof � 0,025 % of the average after correcting for temperature, pressure and viscosity.
5.4.5 Meters shall be installed and operated in accordance with the appropriate recommendations contained in
ISO 2714 or ISO 2715.
6 Apparatus
6.1 Dip-tape and dip-weight
This shall be as specified in ISO 7507-1:1993, B.6 and B.7.
6.2 Ullage paste
NOTE The term "oil-finding paste" is synonymous.
6.3 Water-finding paste
6.4 Ancillary equipment
6.4.1 Air/vapour separator
An air separator, when utilized, shall be fitted upstream of the meter.
A back-pressure valve may be required to maintain an adequate pressure drop across the air release valve fitted to
the air separator.
6.4.2 Flow limiter
A flow limiting device shall be fitted in the line, downstream of the meter, to limit the rate of flow if the pressure of the
calibration liquid supply is such that the flow rate through the installation is too great for the rated capacity of the meter.
6.4.3 Pre-set device
The pre-set device should be leak proof and operate quickly with a smooth action, without causing any undue
pressure surge.
6.4.4 Pressure gauge
Where a positive displacement meter is used, a pressure gauge shall be mounted in the line as close to the meter as
possible, preferably on the downstream side. Where a turbine meter is used, a pressure gauge shall be installed at
least five pipe diameters downstream from the meter. It may be preferable that two pressure gauges are installed
equidistant from the meter upstream and downstream
6.4.5 Shut-off valve
The valve shall be leak proof, and shall operate quickly with a smooth action and without causing an undue pressure
surge.
If a pre-set device is not fitted, a shut-off valve, to shut off the flow at the required intervals, shall be installed
downstream of the meter.
6.4.6 Strainer
6.4.7 Surge suppressor
If surge pressures are likely to occur, a suitable surge suppressor should be fitted to the line.
6.4.8 Syphon breaker
If fitted, the syphon breaker shall be downstream of the meter as close to the delivery point as is possible.
When a tank is being calibrated by top filling, then the syphon breaker should be installed in conjunction with a
weir. The assembly should be fitted at the highest point in the system.
4 © ISO 2001 – All rights reserved
6.4.9 Viewing glass
A viewing glass shall be provided adjacent to/in the air separator if utilized.
6.4.10 Weir
If installed, the weir shall be positioned in such a way as to ensure that the delivery pipe downstream of the meter is full
at all times.
7 Calibration procedure
7.1 General requirements
7.1.1 A tank shall only be calibrated after it has been filled at least once with a liquid of density equal to or
greater than that which it will hold when in use.
NOTE The hydrostatic test applied to new or repaired tanks will satisfy this requirement in most cases.
7.1.2 Before commencing calibration, the system shall be checked for leakage downstream of the meter. Any
leaks found shall be eliminated.
7.1.3 The serial numbers, or identification marks, of thermometers used in the course of calibration shall be
recorded together with their location during the calibration. The thermometers shall be calibrated in accordance
with ISO 4268 and shall be provided with a certificate showing corrections.
7.1.4 Care shall be exercised to avoid the ingress of air into the system when using a meter to calibrate a tank.
It is important that the meter, ancillary equipment and lines be liquid filled before the commencement of calibration.
7.1.5 If fitted, a strainer/filter shall be installed in the line upstream of the meter to protect the meter from
abrasion or other damage from entrained foreign matter.
7.1.6 If the variation of the volume of calibration liquid in the hose connecting the meter to the tank, compared
with the total volume of liquid in the tank, is such that the accuracy of the calibration would be significantly affected,
a syphon breaker shall be placed at the end of the hose to ensure that the hose remains filled with a constant
quantity of liquid.
7.1.7 Excessive variations in the temperature of the calibration liquid shall be avoided if the required accuracy is
to be maintained.
Large fluctuations make it difficult to determine an accurate mean temperature and this in turn causes the following:
a) uncertainties in applying the volume correction factors to the liquid;
b) uncertainties in applying the correction factor for the expansion/ contraction of the measuring equipment;
c) uncertainties in applying the correction factor for the expansion/ contraction of the tank being calibrated.
7.1.8 An adequate supply of the calibration liquid shall be available. The pressure available shall be sufficient, at
all times, to maintain stable flow rates within the normal operating range of the meter.
7.1.9 If a petroleum product is used as the calibration liquid, its depth in the tank shall be measured with product-
finding paste applied in a smooth even film to the dip-tape and dip-weight.
7.1.10 If water is used as the calibration liquid, its depth in the tank shall be measured with water-finding paste
applied in a smooth even film to the dip-tape and dip-weight.
7.1.11 The exact height of the upper reference point above the dip-point shall be determined at the time of
calibration. The overall dipping height shall be marked on the roof of the tank at or near to the dip hatch to which it
applies.
In tanks with a single dip point, the upper reference point shall be clearly marked on the tank and its height above the
dipping datum point shall be recorded at the head of the table. In tanks with more than one dip point, the overall height
at each dip point shall be clearly marked adjacent to the point. This measurement may require adjustment to correct for
the difference between the actual and the certified reference temperature of the dip-tape and dip-weight used to
measure the overall dipping height. The correction shall be calculated in accordance with the equation given in A.3.
7.1.12 If the calibration of the tank is interrupted, it may be resumed at a later date provided that
a) if there is a change of equipment or personnel, sufficient check measurements are made to ensure that the
results obtained prior to the changes correspond within the tolerances laid down in this method,
b) all records of work previously carried out are complete and legible, and
c) the new liquid mean temperature and depth at resumption of operations are recorded.
7.2 Equipment
The calibration of a tank may not necessarily require all of the equipment listed in clause 6. The requirements for each
operation shall be considered before selecting equipment.
7.3 Installation
7.3.1 Figure 1 shows a schematic diagram of a typical installation for calibration by meter.
7.3.2 Attention shall be paid to pipework to ensure minimum pressure drop and turbulence.
Any condition which tends to increase the turbulence of the liquid stream should be avoided.
7.3.3 The meter shall be installed in such a manner that no undue strain is imposed upon it due to the mass or
thermal expansion/contraction of the pipework.
7.3.4 Flexible hoses may be used to provide a supply of liquid for calibration purposes. If they are used on the
downstream side, the total length shall be kept to a minimum.
7.4 Meter proving
7.4.1 The meter shall be proved, on site, using either a volumetric prover tank, meter or pipe prover.
Proving should preferably be carried out using the same fluid as that in the tank.
7.4.2 Proving shall be carried out, as a minimum, immediately prior to commencement and on completion of any
calibration. If the calibration process extends over more than one day, the meter shall be proved at commencement
of calibration and on completion of calibration on each day. Proving may be carried out at shorter intervals to
ensure that the meter or K-factor has not drifted.
NOTE Proving at a central proving station/installation may be acceptable if meters are proved under conditions which
closely replicate those encountered at the calibration site.
6 © ISO 2001 – All rights reserved
Key
1 Tank to be calibrated
2 Flow limiter
3 Non-return valve
4 Thermometer
5 Pressure gauge
6 Air/vapour separator
7 Strainer
8 Supply
9 Meter
10 Syphon breaker
a
To air/vapour separator.
b
To vent.
Figure 1 — Schematic diagram of a typical installation for calibration by meter
7.5 Calibration procedure
7.5.1 The calibration liquid shall be transferred into the tank at a flow rate for which the meter has been
calibrated and at such a rate as to minimize disturbance of the liquid surface in the tank.
Care should be taken during the initial filling of the system to avoid over-ranging of the meter when the air in the
system is being displaced. If flow rates are likely to exceed the rated capacity of the meter, a suitable flow control
valve should be fitted downstream of the meter (see 6.4.2).
7.5.2 The calibration liquid shall be added in incremental volumes sufficient to produce a significant change in
the liquid level with reference to the section of the tank being calibrated, and having due regard to the uncertainty
of liquid level gauging.
NOTE During calibration, the increase in the liquid level is dependent on the size of the liquid volumes introduced into the
tank; i.e. the liquid level is the dependent variable. In a capacity table, the liquid level is the independent variable; the calculation
of the table from field measurements is dependent on the size of the increments added to the tank and to the interpolation
techniques used to calculate the capacity table. Care should be exercised to ensure that the incremental volumes added to the
tank during calibration are of a size which ensures a significant movement in the liquid level but are small enough to minimize
the uncertainty arising from the interpolation technique used in calculating the capacity table.
7.5.3 After the addition of each increment, the liquid surface shall be allowed to settle and the liquid depth
measured at the dip-point by use of a dip-tape and dip-weight.
Liquid depth measurements shall be made and recorded to the nearest millimetre. The depth measurement shall be
taken and shall be repeated. The two measurements shall agree to within 1 mm. If the readings differ from each other
by more than 1 mm, then the depth measurements shall be repeated until two consecutive readings are within the
tolerance limit.
NOTE If ripples on the surface give rise to difficulties in making measurements, a ripple damping device may be used.
7.5.4 After each increase in depth has been measured and recorded, the temperature of the liquid at the meter,
using the thermowell (see 5.1.6) and in the tank shall be taken to the nearest 0,25 °C or better.
NOTE The number of temperature readings may be reduced to one in every five increments if the temperature is found to
be constant.
7.5.5 The ambient air temperature in close proximity to the tank being calibrated shall be measured to the
nearest 0,25 °C, or better, at intervals throughout the calibration period. The recorded temperatures shall be taken
at intervals of time which will accurately reflect the ambient air temperature throughout the calibration process.
7.5.6 If a petroleum product is being used as a calibration liquid, then the pressure on the liquid at the meter
shall be measured and recorded at intervals through out the calibration period. The recorded pressures shall be
taken at intervals of time which will accurately reflect the pressures exerted on the liquid throughout the calibration
process.
7.5.7 If the volume displaced by the inlet hose, compared to the total volume of liquid in the tank, is such that the
accuracy of the calibration would be significantly affected, the inlet hose shall be withdrawn until its lower end is
above the level of the liquid in the tank. Special care and attention shall be exercised to obtain the same amount of
draining before measurements are made of the liquid depth; the liquid surface shall be quiescent.
8 Corrections to observed volumes
8.1 General
Corrections to the observed volumes are required for one or more of the following:
a) calibration error of the meter used;
b) effect of temperature variations on the meter used;
c) effect of temperature variations on the calibration liquid used;
d) effect of temperature variations on the tank being calibrated;
e) effect of temperature variations on the dip-tape and dip-weight used.
If necessary, these corrections shall be calculated and applied when computing a tank capacity table. The tank
calibrator shall ensure that all necessary details for the calculation of the corrections are included in the calibration
notes.
8.2 Meter factor and K-factor
8.2.1 The meter factor or K-factor for the meter in use shall be the average of the factors calculated at the
commencement and completion of the calibration.
8.2.2 The meter factor or K-factor at the commencement and completion of the calibration shall not differ by
more than 0,05 %. If the two factors differ by more than 0,1 % then the reason for the difference shall be
determined and, if necessary, the calibration shall be repeated.
8 © ISO 2001 – All rights reserved
8.3 Temperature changes in the calibration liquid
8.3.1 A correction shall be made for any change in the temperature of the calibration liquid between the time that
it is measured in the meter and the time that it is measured in the tank being calibrated.
8.3.2 If the calibration liquid used is a petroleum product and the tank calibration table is required to be correct at
either 15 °Cor 20 °C, the volume delivered shall be corrected for temperature changes in the calibration liquid by
using the Volume Correction Factor (VCF) table for petroleum products in ISO 91-1:1992 or ISO 91-2:1991
respectively.
8.3.3 If the calibration liquid used is water and the tank calibration table is required to be correct at 15 °C, the
volume delivered shall be corrected for temperature changes in the calibration liquid by using the table of water
densities or the formula given in annex A.
8.3.4 The corrections shall be made in the following order:
a) correction of the observed calibration liquid temperature to reference temperature;
b) correction of the capacity of the container shell for thermal effects;
c) correction of the liquid level measurement/dip-tape and dip-weight for thermal effects.
8.4 Temperature changes in the tank shell
A correction for the difference in temperature between the shell of the tank at the time of calibration and its average
temperature in service, or between the temperature at calibration and a standard reference temperature, e.g. 15 °C,
shall be made according to the method given in annex A. The tank shell temperature shall be determined by one of the
methods given in annex A of either ISO 7507-1:1993 or ISO 7507-6:1997.
8.5 Temperature effects on dip-tapes and other measures of length
Dip-tapes and other measures of length are calibrated at 20 °C but if they are used at other temperatures, within the
range 20 °C � 5 °C, the corrections for temperature changes are small (of the order of 1 mm in 18 m) and may be
neglected in all cases. Outside this range, a correction is required (see A.3).
8.6 Method of correcting for temperature effects
8.6.1 When the total capacity of the tank has been calibrated by meter and the tank capacity table is required to
be at a reference temperature of either 15 °Cor20 °C the corrections in 8.4 to 8.5 may be conveniently combined.
8.6.2 If calibration is required to be correct at some other temperature, the adjustment to the standard
temperature shall first be made and a further correction calculated for the thermal expansion or contraction of the
tank shell shall be in accordance with annex A.
9 Calculation of tank capacity tables
9.1 All calculations shall be made in accordance with accepted mathematical principles.
Errors in calculation are minimized and checking facilitated by the adoption of a standard form of data and
calculation sheet. The use of the forms illustrated in annex B is recommended for site data collection and for
calculation.
9.2 Tank capacity tables
9.2.1 Provided that tank capacity tables have been calculated in accordance with the principles given in this part
of ISO 4269, the format adopted will not affect the mathematical correctness of the table. However, the principles
laid down in this clause are recommended since they provide a table in a form most convenient for use. Each tank
calibrated in accordance with this part of ISO 4269 shall be issued with a certificate of calibration as specified in
ISO 7507-1:1993, annex E.
9.2.2 At the head of each tank calibration table it shall be clearly stated the method by which the liquid level for
entry to the tank capacity table shall be determined.
9.2.3 Table headings shall show the tank reference number and location, the temperature at which the table is
correct, and the date of calibration.
9.2.4 The intervals of dip at which the table is set out shall be chosen so as to allow linear interpolation for
intermediate dips without significant loss of accuracy.
10 Requirements for calculations
10.1 All readings of instruments shall be recorded as observed, without correction for errors which shall be shown
separately. Recorded figures shall be checked for consistency before proceeding to the next entry. In all cases of
doubt, the readings shall be verified.
10.2 Temperature shall be recorded to at least the nearest 0,25 °C.
10.3 Volumetric readings shall be recorded to the nearest graduation on the meter registers.
10.4 All correction factors obtained from tables shall be used without rounding.
10.5 Other correction factors which require to be calculated shall be correct to 5 significant figures.
10.6 All calculations shall be carried out to be correct to at least 5 significant figures.
10.7 Depth measurements which shall be recorded to the nearest 1 mm, and shall be shown corrected to the
nearest 1 mm.
10.8 The final tables shall be calc
...
NORME ISO
INTERNATIONALE 4269
Première édition
2001-03-15
Pétrole et produits pétroliers liquides —
Jaugeage des réservoirs par épalement —
Méthode par empotement utilisant des
compteurs volumétriques
Petroleum and liquid petroleum products — Tank calibration by liquid
measurement — Incremental method using volumetric meters
Numéro de référence
©
ISO 2001
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ii © ISO 2001 – Tous droits réservés
Sommaire Page
Avant-propos.iv
Introduction.v
1 Domaine d'application.1
2Références normatives .1
3Termesetdéfinitions.2
4Précautions .2
5 Compteurs.2
6 Appareillage .4
7Procédures de jaugeage .5
8 Correction des volumes relevés .8
9 Calcul des barèmes de jaugeage des réservoirs .10
10 Calculs .10
Annexe A (normative) Corrections pour les effets thermiques .12
Annexe B (informative) Données relevées sur le terrain et tableaux de calculs .18
Bibliographie .26
Avant-propos
L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes nationaux de
normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est en général confiéeaux
comités techniques de l'ISO. Chaque comité membre intéressé par une étude aledroit de fairepartie ducomité
technique créé à cet effet. Les organisations internationales, gouvernementales et non gouvernementales, en
liaison avec l'ISO participent également aux travaux. L'ISO collabore étroitement avec la Commission
électrotechnique internationale (CEI) en ce qui concerne la normalisation électrotechnique.
Les Normes internationales sont rédigées conformément aux règles données dans les Directives ISO/CEI, Partie 3.
Les projets de Normes internationales adoptés par les comités techniques sont soumis aux comités membres pour
vote. Leur publication comme Normes internationales requiert l'approbation de 75 % au moins des comités
membres votants.
L’attention est appelée sur le fait que certains des éléments delaprésente partie de l’ISO 4269 peuvent faire
l’objet de droits de propriété intellectuelle ou de droits analogues. L’ISO ne saurait être tenue pour responsable de
ne pas avoir identifié de tels droits de propriété et averti de leur existence.
La Norme internationale ISO 4269 a étéélaborée par le comité technique ISO/TC 28, Produits pétroliers et
lubrifiants, sous-comité SC 3, Mesurage statique du pétrole.
L’annexe A constitue un élément normatif de la présente Norme internationale. L'annexe B est donnée uniquement
à titre d'information.
iv © ISO 2001 – Tous droits réservés
Introduction
La présente Norme internationale est une partie d'une série de normes sur le jaugeage des réservoirs qui
comprend:
l'ISO 7507-1, l'ISO 7507-2, l'ISO 7507-3, l'ISO 7507-4, l'ISO 7507-5, l'ISO 7507-6, l'ISO 8311, l'ISO 9091-1 et
l'ISO 9091-2.
Les méthodes de jaugeage par transfert de liquides peuvent être utilisées pour le jaugeage de la capacité totale ou
partielle d’un réservoir. Une grande exactitude peut être obtenue à condition d’effectuer avec soin toutes les étapes
de l’opération. La méthode est particulièrement utile pour les réservoirs de forme irrégulière, pour le jaugeage du
fond de tout bac de stockage, ou pour le jaugeage des citernes de bateaux et de barges dont les formes
géométriques sont irrégulières.
Cette méthode donne un degré d’exactitude, qui peut dépasser celui d’autres méthodes lorsqu’elle est utilisée pour
le jaugeage de petits réservoirs, notamment pour les réservoirs cylindriques horizontaux.
Le liquide de jaugeage peut êtredel’eauoutoutautre liquide pétrolier de faible volatilité et de faible viscosité.En
cas de variations importantes de température au cours du jaugeage, l’utilisation de l’eau est recommandée à cause
de son faible coefficient d’expansion cubique. L'utilisation de l’eau peut par contre entraîner des difficultés et des
risques inacceptables, selon l’affectation du réservoir à jauger; par exemple, l'utilisation et l'élimination de l’eau
pour le jaugeage des réservoirs de stockage enterrés chez les revendeurs. Il est préférable dans de telles
situations d'utiliser un produit pétrolier adapté.
NORME INTERNATIONALE ISO 4269:2001(F)
Pétrole et produits pétroliers liquides — Jaugeage des réservoirs
par épalement — Méthode par empotement utilisant des
compteurs volumétriques
1 Domaine d'application
La présente Norme internationale prescrit des méthodes de jaugeage des réservoirs par ajout de quantités
connues de liquide. Le liquide est utilisé comme intermédiaire pour le transfert de volume, et mesuré avec
exactitude au moyen d’un compteur.
La présente Norme internationale ne s’applique pas à l’étalonnage des instruments de mesure de référence, des
jauges étalons et des tubes étalons.
NOTE Les normes applicables sont données dans la bibliographie.
2Références normatives
Les documents normatifs suivants contiennent des dispositions qui par suite de la référence qui y est faite,
constituent des dispositions valables pour la présente Norme internationale. Pour les références datées, les
amendements ultérieurs ou les révisions de ces publications ne s’appliquent pas. Toutefois, les parties prenantes
aux accords fondés sur la présente Norme internationale sont invitées à rechercher la possibilité d'appliquer les
éditions les plus récentes des documents normatifs indiqués ci-après. Pour les références non datées, la dernière
édition du document normatif en référence s’applique. Les membres de l'ISO et de la CEI possèdent le registre des
Normes internationales en vigueur.
ISO 91-1:1992, Tables de mesure du pétrole — Partie 1: Tables basées sur les températures de référence de
15 °Cet60 °F.
ISO 91-2:1991, Tables de mesurage du pétrole — Partie 2: Tables basées sur la température de référence de
20 °C.
ISO 2714:1980, Hydrocarbures liquides — Mesurage volumétrique au moyen de compteurs à chambre mesureuse
autres que ceux des ensembles de mesurage routiers.
ISO 2715:1981, Hydrocarbures liquides — Mesurage volumétrique au moyen de compteurs à turbine.
ISO 4268, Pétrole et produits pétroliers liquides — Mesurages de la température — Méthodes manuelles.
ISO 7507-1:1993, Pétrole et produits pétroliers liquides — Jaugeage des réservoirs cylindriques verticaux —
Partie 1: Méthode par ceinturage.
ISO/TR 7507-6:1997, Pétrole et produits pétroliers liquides — Jaugeage des réservoirs cylindriques verticaux —
Partie 6: Recommandations relatives à la surveillance, au contrôle et à la vérification du jaugeage des réservoirs et
des tables de jaugeage.
ISO 9770:1989, Pétrole brut et produits pétroliers — Facteurs de compressibilité des hydrocarbures dans la plage
3 3
de 638 kg/m à 1074kg/m .
CEI 60079-10, Matériel électrique pour atmosphères explosives gazeuses — Partie 10: Classement des régions
dangereuses.
3 Termes et définitions
Pour les besoins de la présente Norme internationale, les termes et définitions donnésdansl’ISO 7507-1 ainsi que
lestermesetdéfinitions suivants s'appliquent.
3.1
facteur K
nombre d’impulsions générées par un compteur par unité de volume du produit qui le traverse
3.2
dispositif de prédétermination
équipement qui interrompt le transfert du liquide de jaugeage au travers du compteur aprèsqu’un volume
prédéterminé a traversé ce compteur
4Précautions
4.1 Les précautions générales et relatives à la sécurité définies dans l’ISO 7507-1 et la CEI 60079-10 doivent
être respectées pour la présente Norme internationale.
4.2 Lorsque le liquide de jaugeage est un produit pétrolier, les précautions supplémentaires suivantes doivent
être observées, sans que cette liste soit exhaustive:
a) contrôle des risques potentiels de mise à feu;
b) préventiondel’accumulation électrostatique par:
1) une bonne liaison des tuyaux de raccordement,
2) le contrôle des débits de pompage,
3) le remplissage du réservoir en évitant l’écoulement du liquide en pluie et les éclaboussures,
–1
4) le maintien de la vitesse du liquide dans la tuyauterie à un niveau inférieur à 1ms jusqu’à l’immersion
de l’extrémité du tube de remplissage.
5 Compteurs
5.1 Spécifications générales
5.1.1 Le compteur doit être volumétrique ou à turbine.
5.1.2 Le compteur doit être fabriquéà partir de matériaux adaptés au liquide utilisé pour le jaugeage.
5.1.3 On doit sélectionner le compteur afin que son débit, pendant le jaugeage du réservoir, se situe dans la
partie linéaire de la courbe d’erreur du compteur.
Il convient de munir le compteur d’un dispositif indicateur de débit; dans le cas contraire, les débits moyens sont
calculés par chronométrage des quantitéslivrées.
5.1.4 Le compteur doit être muni d’un indicateur de volume, ou d’un compteur électronique d’impulsions utilisé
pour calculer les volumes.
Afin de pouvoir déterminer la répétabilité pendant l’étalonnage du compteur, et en fonction du volume qui le
traverse au cours de cet étalonnage, il convient d'utiliser un compteur d’impulsions spécial ou tout autre indicateur
permettant la lecture d’unefractiondel’unité de volume.
2 © ISO 2001 – Tous droits réservés
5.1.5 On doit disposer d’une jauge étalon, d’un tube étalon ou d’un dispositif étalon de faible volume, adaptésau
type de compteur utilisé afin d’étalonner le compteur. Les appareils sélectionnés doivent être munis d’un certificat
d’étalonnage donnant les corrections nécessaires à leur utilisation.
5.1.6 On doit disposer d’un puits thermométrique (doigt de gant) adjacent au compteur.
Si le compteur utilisé est du type volumétrique, il est recommandé d’installer le puits thermométrique dans le corps
même du compteur, afin d’obtenir une bonne immersion et une bonne réponse thermique, et éviter les effets
indésirables liés à la conduction thermique de la paroi de la tuyauterie, notamment dans le cas des lignes de faible
diamètre; dans le cas d'utilisation de compteur de turbine, il convient d'installer le doigt de gant dans la canalisation
à une distance au moins égale à cinq fois les diamètres de la tuyauterie en aval du compteur. Il convient que ce
puits soit en contact direct avec le liquide de jaugeage, et soit rempli d’huile légère pour faciliter la réponse
thermique. Il convient que le puits et l’élément dans lequel la partie sensible du thermomètre est immergéesoient
conçus conformément aux principes des techniques de la thermique. Il peut être souhaitable de prévoir une
isolation thermique externe autour de la tuyauterie ou au niveau du puits thermométrique.
5.1.7 On doit installer en aval du compteur une vanne ou un dispositif d’arrêt (voir 6.4.5) à temps de réponse
rapide.
5.2 Compteurs volumétriques
La courbe d’erreur du compteur ne doit pas s’écarter de plus de � 0,20 % du facteur moyen du compteur entre
10%et 100%dudébit maximal du compteur.
5.3 Turbines
5.3.1 Le facteur K ne doit pas s’écarter de � 0,20 % de sa valeur moyenne entre 10 % et 100 % du débit
maximal de la turbine.
5.3.2 On doit exercer une contre-pression supérieure à 100 kPa pour éviter toute cavitation.
5.4 Sélectionducompteur
5.4.1 La sélection du compteur utilisé pour le jaugeage des réservoirs dépend des éléments suivants:
a) le débit pendant le jaugeage du réservoir (voir 5.4.4);
b) la pression maximale à laquelle va être soumis le compteur;
c) le liquide mesuré par le compteur (voir 5.1.2);
d) la plage de température de fonctionnement du compteur;
e) la plage de viscosité de fonctionnement du compteur.
5.4.2 On ne doit pas utiliser de compteurs à compensateur de température pour le jaugeage des réservoirs.
5.4.3 Le compteur doit être fourni avec une courbe de correction ou de facteur K (courbe d’erreur en fonction du
débit) correspondant au type de liquide, à la viscosité, à la température et à la plage de débit utilisés.
5.4.4 La répétabilité du compteur doit être telle que cinq résultats d’essais successifs se situent à � 0,025 % de
la valeur moyenne obtenue aprèscorrectiondel’influencedelatempérature, de la pression et de la viscosité.
5.4.5 Les compteurs doivent être installés et mis en service conformément aux recommandations contenues
dans les normes ISO 2714 et ISO 2715.
6 Appareillage
6.1 Ruban de pige et lest gradué
Tel que spécifié dans l'ISO 7507-1:1993, B.6 et B.7.
6.2 Pâte indicatrice de produit
NOTE Le terme «pâte détectrice de produit pétrolier utiliséelors d’opérations de mesurage de la hauteur de creux» est
synonyme.
6.3 Pâte détectrice d’eau
6.4 Équipements auxiliaires
6.4.1 Séparateur air/gaz
Le séparateur de gaz doit être installé en amont du compteur lorsqu’il est utilisé.
Il peut s'avérer nécessaire de prévoir une vanne de maintien de pression pour maintenir une différence de pression
suffisante d’air au niveau du clapet d’évacuation d’air du séparateur.
6.4.2 Limiteur de débit
Un dispositif de limitation de débit doit être installé sur la ligne en aval du compteur, pour limiter le débit lorsque la
pression d’alimentation du liquide de jaugeage est telle que le débit dans l’installation est susceptible de dépasser
le débit maximal du compteur.
6.4.3 Dispositif de prédétermination
Il convient que le dispositif de prédétermination soit étanche et fonctionne rapidement et sans à-coups, sans
provoquer de montéeenpression indésirable.
6.4.4 Manomètre
En cas d’utilisation d’un compteur volumétrique, installer sur la ligne un manomètre aussi près que possible du
compteur, de préférence côté aval. En cas d’utilisation d’un compteur à turbine, monter un manomètre à une
distance du compteur égale au moins à cinq fois le diamètre de la tuyauterie. Il peut être préférable d’installer deux
manomètres àégale distance du compteur, en amont et en aval.
6.4.5 Dispositif d’arrêt
La vanne doit être étanche, se déclencher rapidement, fonctionner sans à-coups et sans provoquer de montéeen
pression indésirable.
En l’absence de tout dispositif de prédétermination, installer en aval du compteur une vanne d’arrêtpour arrêter
l’écoulement aux intervalles souhaités.
6.4.6 Filtre
6.4.7 Limiteur de surpression
S’il est possible d’avoir des surpressions, il convient alors d’installer un limiteur de surpression sur la ligne.
4 © ISO 2001 – Tous droits réservés
6.4.8 Dispositif casse-vide
Lorsqu'un dispositif casse-vide est utilisé,ildoit être installé en aval du compteur, aussi près que possible du point
de transfert.
Lorsque le jaugeage d’un réservoir se fait avec remplissage par le haut, il convient que le dispositif casse-vide soit
installé avec un dispositif de niveau constant. Cet ensemble doit être installé au point le plus élevé du système.
6.4.9 Viseur
Prévoir un viseur adjacent ou sur le corps du séparateur de gaz s’il est utilisé.
6.4.10 Dispositif de niveau constant
Si nécessaire, un dispositif de niveau constant doit être placé de manière à s’assurer que le tube de remplissage,
en aval du compteur, est constamment plein.
7Procédure de jaugeage
7.1 Caractéristiques générales
7.1.1 Un réservoir doit être jaugé seulement aprèsqu’il a été rempli au moins une fois avec un liquide de masse
volumique égale ou supérieure àcelleduliquidequ’il contiendra en service.
NOTE L’essai hydrostatique des réservoirs neufs ou réparésrépond à cette condition dans la plupart des cas.
7.1.2 Avant le début de chaque jaugeage, vérifier l’étanchéité du système en aval du compteur. Toute fuite
identifiéedoit être éliminée.
7.1.3 Enregistrer les numéros de série ou les marques d’identification des thermomètres utilisésau cours du
jaugeage, avec leur emplacement pendant le jaugeage. Les thermomètres doivent être étalonnés conformément à
l'ISO 4268, et avoir un certificat d’étalonnage mentionnant les corrections à apporter.
7.1.4 Prendre soin d’éviter toute entréed’air dans le système lorsqu’un compteur est utilisé pour le jaugeage
d’un réservoir.
Il est important de remplir de liquide le compteur, les dispositifs annexes et les tuyauteries avant de commencer le
jaugeage.
7.1.5 Si besoin, un filtre doit être installé sur la tuyauterie en amont du compteur, pour protéger ce dernier de
toute usure ou d’autre dégâts que provoqueraient des corps étrangers.
7.1.6 Si la variation du volume du liquide de jaugeage contenu dans le flexible qui relie le compteur au réservoir,
comparé au volume total de liquide dans le réservoir, est telle qu’elle modifie l’exactitude du jaugeage de façon
significative, placer un dispositif casse-vide à l’extrémité du flexible pour s’assurer que ce dernier conserve une
quantité constante de liquide.
7.1.7 Éviter des variations excessives de température du liquide de jaugeage pour maintenir l’exactitude
nécessaire.
Les fluctuations importantes rendent difficiles la détermination d’une température moyenne exacte, laquelle à son
tour entraîne:
a) des incertitudes dans l’application des facteurs de correction du volume du liquide;
b) des incertitudes dans l’application du facteur de correction de la dilatation ou de la contraction de l’équipement
de mesure;
c) des incertitudes dans l’application du facteur de correction de la dilatation ou de la contraction du réservoir
jaugé.
7.1.8 Disposer d’une quantité suffisante de liquide de jaugeage. Prévoir une pression suffisante à tous moments,
pour que les débits soient stables dans les conditions habituelles de fonctionnement du compteur.
7.1.9 Si le liquide de jaugeage utilisé est un produit pétrolier, mesurer sa hauteur dans le réservoir avec une pâte
indicatrice de produits pétroliers, appliquée encouchefineet uniformesur lerubandepigeetsur le lestgradué.
7.1.10 Si le liquide de jaugeage utilisé est de l’eau, mesurer sa hauteur avec une pâte détectrice d’eau, appliquée
en couche fine et uniforme sur le ruban de pige et sur le lest gradué.
7.1.11 Déterminer la hauteur exacte entre le point de référence supérieur et le point de référence inférieur définis
lors du jaugeage. Marquer la hauteur totale témoin sur le toit du réservoir, ou à proximité de l’orifice de repérage
des niveaux utilisé.
Pour les réservoirs qui n’ont qu’un seul orifice de repérage des niveaux, marquer clairement le point de référence
supérieur sur le réservoir, et inscrire en tête de barème la hauteur totale témoin. Pour les réservoirs munis de
plusieurs orifices de repérage de niveau, indiquer clairement la hauteur totale à proximité de chaque orifice. Il peut
s’avérer nécessaire de corriger cette mesure en tenant compte de la différence entre la température de référence
du ruban de pige et du lest gradué utilisés pour mesurer la hauteur totale avec la température réelle du mesurage.
Calculer la correction d’aprèsl’équation donnéeenA.3.
7.1.12 En cas d’interruptiondujaugeageduréservoir, il peut être repris ultérieurement à condition que:
a) en cas de changement d’équipement ou de personnel, les mesures de vérification soient suffisantes pour
s’assurer que les résultats obtenus antérieurement et postérieurement au changement ne diffèrent pas d’une
valeur supérieure aux tolérances fixées pour la présente méthode;
b) l’enregistrement du travail effectué antérieurement soit complet et lisible;
c) la nouvelle température moyenne du liquide et sa hauteur soient enregistrées dès la reprise des opérations.
7.2 Équipement
Il n’est pas forcément nécessaire d’utiliser l’ensemble des équipements de la liste de l'article 6 pour le jaugeage
des réservoirs. Avant de sélectionner les équipements, définir les caractéristiques de chaque opération.
7.3 Installation
7.3.1 La Figure 1 donne une représentation schématique d’un exemple courant d’installation de jaugeage par
compteur.
7.3.2 On doit s’assurer que les canalisations soient telles qu’il n’yait qu’un minimum de pertes de charge et de
turbulences.
Il convient d'éviter toute situation qui tendrait à augmenter les turbulences dans l’écoulement du liquide.
7.3.3 Le compteur doit être installé de façon qu’aucune contrainte indésirablenelui soit imposée, qui serait
provoquée par le poids, la dilatation ou la contraction thermique des canalisations.
7.3.4 Des flexibles souples peuvent être utilisés pour l’alimentation en liquide pour le jaugeage. S'ils sont montés
du côté aval, leur longueur totale doit être maintenue aussi faible que possible.
7.4 Étalonnage du compteur
7.4.1 Le compteur doit être étalonné en utilisant soit une jauge étalon, soit un compteur étalonou soit untube
étalon.
6 © ISO 2001 – Tous droits réservés
Il convient de réaliser l’étalonnage du compteur de préférenceenutilisantlemême fluide que celui utilisé pour le
jaugeage du réservoir.
7.4.2 L’étalonnage doit être effectué, au minimum, immédiatement avant chaque jaugeage et dèsl’achèvement
de celui-ci. Si le jaugeage prend plus d’une journée, étalonner le compteur chaque jour au début du jaugeage et
dès son arrêt. L’étalonnage peut être effectuéà des périodicités plus courtes, pour s’assurer que le compteur ou
que le facteur K n’a pas dérivé.
NOTE Il peut être acceptable d’effectuer l’étalonnage dans des stations ou des installations centrales d’étalonnage à
condition que l’étalonnage des compteurs reproduise avec fidélité les conditions rencontrées sur le terrain.
Légende
1Réservoir à jauger
2 Limiteur de débit
3 Vanne anti-retour
4 Thermomètre
5 Manomètre
6Séparateur de gaz
7 Filtre
8 Alimentation
9 Compteur
10 Dispositif casse-vide
a
Vers le séparateur de gaz.
b
Vers l'atmosphère.
Figure 1 — Schéma d'un exemple courant d'installation de jaugeage par compteur
7.5 Mode opératoire de jaugeage
7.5.1 Le liquide de jaugeage doit être transféré dans le réservoir, à un débit pour lequel le compteur a été
étalonné, et de telle sorte que le débit perturbe au minimum la surface du liquide dans le réservoir.
Pendant le remplissage initial du système, il convient de s’assurer que le compteur ne se mette pas en sur-régime
lors du déplacement de l’air dans le système. Si le débit est susceptible de dépasser le débit maximal du compteur,
il convient de monter une vanne de contrôle de débit en aval du compteur (voir 6.4.2).
7.5.2 Le liquide de jaugeage doit être introduit par volumes successifs suffisants pour produire un changement
significatif du niveau de liquide, fonction de la forme géométrique du réservoir jaugé,et de l’incertitude sur le
repérage du niveau.
NOTE Au cours du jaugeage, l'accroissement du niveau du liquide dépend du volume de liquide introduit dans le réservoir,
c’est-à-dire que le niveau du liquide est la variable dépendante. Dans un barème de jaugeage, le niveau du liquide est la
variable indépendante; le calcul du barème issu des mesures sur le site dépend des volumes successifs ajoutés de liquide dans
le réservoir, et des techniques d’interpolation utilisées pour établir le barème. Il convient de porter une attention particulière pour
s’assurer que les volumes successifs ajoutés dans le réservoir pendant le jaugeage sont d'une taille suffisante pour assurer un
changement de niveau de liquide significatif, mais suffisamment petit pour minimiser l’incertitude provenant de la technique
d’interpolation utiliséepour établir le barème.
7.5.3 Après chaque ajout de liquide, laisser reposer la surface du liquide, et mesurer sa hauteur au point de
référence, en utilisant un ruban de pige et un lest gradué.
Prendre les mesures de la hauteur du liquide et les enregistrer au millimètre près. Effectuer chaque mesure de
hauteur en la répétant. Les deux mesures doivent concorder au millimètre près. Si les deux relevésdiffèrent de
plus de 1 mm, recommencer la mesure de la hauteur jusqu’à ce que les deux mesures successives soient situées
dans les limites tolérées.
NOTE Si la mesure est gênée par des vagues à la surface du liquide, il convient d'utiliser un dispositif atténuateur de ces
vagues.
7.5.4 Aprèsavoir mesuré et noté chaque augmentation de la hauteur du liquide, relever la température du
liquide au niveau du compteur, en utilisant le puits thermométrique (voir 5.1.6), et dans le réservoir, à 0,25 °Cprès
ou mieux.
NOTE Le nombre de relevésde température peut être réduit à un tous les cinq empotements successifs si la température
s’avère constante.
7.5.5 Mesurer à 0,25 °Cprès au moins la température de l’air dans le voisinage proche du réservoir à jauger, à
intervalles donnés pendant la période du jaugeage. Relever les températures à des intervalles de temps qui sont le
reflet exact de la température ambiante de l’air pendant le jaugeage.
7.5.6 Si le liquide de jaugeage est un produit pétrolier, mesurer et enregistrer la pression du liquide à intervalles
donnés pendant la période de jaugeage. Enregistrer les pressions à des intervalles de temps qui sont le reflet
exact de la pression exercée sur le liquide pendant le jaugeage.
7.5.7 Si le volume déplacé par le flexible de remplissage, comparé au volume total de liquide contenu dans le
réservoir est tel qu’il peut modifier de façon significative l’exactitude du jaugeage, remonter ce flexible de
remplissage jusqu’à ce que son extrémité inférieure se trouve au-dessus de la surface du liquide dans le réservoir.
Prendre soin tout particulièrement de drainer la même quantité de liquide avant chaque mesure de hauteur du
liquide; la surface du liquide doit êtreaurepos.
8 Correction des volumes relevés
8.1 Généralités
Il est nécessaire d’apporter des corrections aux volumes relevéssur l’un ou plusieurs des points suivants:
a) erreur d’étalonnage du compteur utilisé;
b) effet des variations de la température sur le compteur utilisé;
c) effet des variations de la température sur le liquide de jaugeage utilisé;
d) effet des variations de la température sur le réservoir qui est jaugé;
8 © ISO 2001 – Tous droits réservés
e) effet des variations de la température sur le ruban de pige et sur le lest gradué utilisés.
Calculer ces corrections si nécessaire, et les appliquer lors du calcul du barème de jaugeage du réservoir. Une fois
le jaugeage du réservoir terminé,s’assurer que l’ensemble des détails nécessaires au calcul des corrections se
trouve bien dans le rapport de jaugeage.
8.2 Courbe d’erreur du compteur et facteur K
8.2.1 Pour le compteur utilisé, lacourbed’erreur et le facteur K doivent représenter la moyenne des facteurs
calculésaudébut et à la fin du jaugeage.
8.2.2 Au début et à la fin du jaugeage, la courbe d’erreur ou le facteur K ne doivent pas varier de plus de 0,05 %.
Si les deux facteurs diffèrent de plus de 0,05 % l’un de l’autre, identifier la raison de cette différence et, si
nécessaire, recommencer le jaugeage.
8.3 Changements de température du liquide de jaugeage
8.3.1 Unecorrectiondoit être effectuée pour toute variation de température du liquide de jaugeage qui
surviendrait entre le moment où elle est relevée dans le compteur et celui où elle est mesurée dans le réservoir à
jauger.
8.3.2 Si le liquide de jaugeage utilisé est un produit pétrolier et que le barème de jaugeage du réservoir
nécessite d’être corrigéà 15 °Cou à 20 °C, corriger le volume d'épalement en fonction des changements de
température du liquide de jaugeage, en utilisant la table de facteur de correction du volume (VCF) des produits
pétroliers de l'ISO 91-1 ou l'ISO 91-2 respectivement.
8.3.3 Si le liquide de jaugeage utilisé est de l’eau et que le barème de jaugeage du réservoir nécessite d’être
corrigéà 15 °C, corriger le volume d'épalement en fonction des changements de température du liquide de
jaugeage, en utilisant le tableau des masses volumiques de l’eau ou la formule donnée dans l’annexe A.
8.3.4 Apporter les corrections dans l’ordre qui suit:
a) correctiondelatempérature du liquide de jaugeage observée par rapport à la température de référence;
b) correctiondelacapacité du réservoir en fonction des effets thermiques sur la paroi;
c) corrections de la mesure du niveau du liquide, du ruban de pige et du lest gradué en fonction des effets
thermiques.
8.4 Changements de température de la paroi du réservoir
Unecorrectiondoit être effectuée sur la différence de température entre la paroi du réservoir lors du jaugeage et sa
température moyenne en service, ou entre la température au moment du jaugeage et celle de référence, par
exemple 15 °C; effectuer cette correction conformément à la méthode donnée dans l’annexe A. Déterminer la
température de la paroi du réservoir selon l’une des méthodes donnée soit dans l'ISO 7507-1:1993, annexe A, soit
dans l’ISO 7507-6.
8.5 Effets de la température sur les rubans de pige et sur les autres systèmesdemesurede
longueur
Les rubans de pige et les autres systèmes de mesure de longueur sont étalonnés à 20 °C, mais dans les cas
d’utilisation à d’autres températures, dans l’étendue 20 °C � 5 °C, les changements de température n’entraînent
que de faibles corrections (de l’ordre de 1 mm pour 18 m) et peuvent être négligésdanstous lescas. Horsde cette
étendue de température, apporter une correction (voir A.3).
8.6 Méthode de correction des effets de température
8.6.1 Une fois la capacité totale du réservoir jaugée avec un compteur et une fois fixéela température de
référence pour le barème de jaugeage du réservoir à 15 °Cou à 20 °C, les corrections de 8.4 et de 8.5 peuvent
être utilisées commeilsedoit.
8.6.2 Si le barème de jaugeage doit être corrigéà d’autres températures, l’ajustement à la température de
référence doit être effectué en premier lieu, et ensuite la correction pour la dilatation ou la contraction thermique de
la paroi du réservoir, doit être calculée conformément à l’annexe A.
9 Calcul des barèmesdejaugeagedes réservoirs
9.1 Généralités
Effectuer tous les calculs en suivant des principes mathématiques reconnus.
Afin de limiter les erreurs et de faciliter les vérifications, il est commode d'adopter un formulaire normalisé pour les
feuilles de données et les tableaux de calculs. Il est recommandé d’utiliser les tableaux de l’annexe B pour les
données enregistrées sur le site et pour les calculs.
9.2 Barèmes de jaugeage des réservoirs
9.2.1 Dès lors que les barèmes de jaugeage des réservoirs ont été calculés en suivant les principes donnés
dans la présente Norme internationale, le format adopté n’influencera pas la justesse des résultats mathématiques
des tables. Il est néanmoins recommandé d’utiliser l’ensemble des principes présentésdansleprésent article,
étant donné qu’ils permettent d’obtenir une table sous une forme qui convient le mieux à son utilisation. Chaque
réservoir jaugé conformément aux principes de la présente partie de l'ISO 4269 doit recevoir un certificat de
jaugeage tel que prescrit dans l'ISO 7507-1:1993, annexe E.
9.2.2 En tête de chaque barème de jaugeage, préciser clairement la méthode de détermination du niveau de
liquide utilisé dans le barème de jaugeage du réservoir.
9.2.3 Dans l’en-tête des barèmes de jaugeage doivent apparaîtrelenuméro de référenceduréservoir et son
emplacement, la température à laquelle la table est utilisable ainsi que la date du jaugeage.
9.2.4 Les espacements entre les hauteurs du barème doivent être sélectionnésde façon qu’une interpolation
linéaire pour les relevés de hauteurs intermédiaires n’engendre pas une perte significative d’exactitude.
10 Calculs
10.1 Enregistrer les relevés des instruments tels qu’ils sont observés, sans apporter de correction d’erreur qui doit
apparaître séparément. Vérifier la cohérence des chiffres notés avant de passer au relevé suivant. En cas de
doute, vérifier l’ensemble des relevés.
10.2 Noter la température à au moins 0,25 °Cprès.
10.3 Inscrire les relevés des données volumétriques à l’échelon le plus proche sur l’indicateur du compteur.
10.4 Utiliser tous les facteurs de correction obtenus à partir des tables sans les arrondir.
10.5 Les autres facteurs de correction à calculer, doivent être exprimés avec cinq chiffres significatifs au moins.
10.6 Tous les calculs effectués doivent être exprimés avec au moins cinq chiffres significatifs.
10.7 Enregistrer les mesures de hauteur à 1mm près, et les corriger à 1mm près.
10 © ISO 2001 – Tous droits réservés
10.8 Calculer les barèmes de jaugeage par interpolation à partir des volumes cumuléscorrigés.
10.9 Les volumes figurant sur les barèmes de jaugeage des réservoirs et obtenus par interpolation doivent être
arrondis au litre le plus proche et reportés en face de chacune des valeurs de hauteur de plein ou de creux.
10.10 Dans le cas d’utilisation d’un produit pétrolier comme liquide de jaugeage, la pression du liquide doit avoir
été mesurée, et inscrite à intervalles donnés au cours du jaugeage si nécessaire. Une correction pour tenir compte
de la compressibilité du liquide peut être calculée, en utilisant un facteur du Tableau 1, soit des tables de
l'ISO 9770:1989, dont le Tableau 1 est extrait.
10.11 Lorsqu’un réservoir cylindrique vertical est entièrement jaugé selonlaméthode par épalement, le barème
de jaugeage définitif du réservoir comprend automatiquement les corrections dues aux effets hydrostatiques
(correction due à la charge du liquide) engendrées par des modifications de dimensions du réservoir; mais ceci ne
s’applique qu’aux liquides de masse volumique voisine de celle du liquide de jaugeage utilisé. Si le liquide que
contiendra le réservoir pendant son utilisation future a une masse volumique significativement différente de celle du
liquide de jaugeage, prévoir une correction pour tenir compte des effets dus à la charge hydrostatique du liquide.
Calculer les corrections dues à la charge hydrostatique du liquide en suivant l'ISO 7507-1.
10.12 Si le jaugeage d’un réservoir cylindrique se fait en partie par la méthode par épalement et en partie par
une autre méthode, il peut être nécessaire d’effectuer une correction due à la charge hydrostatique du liquide lors
du calcul du barème de jaugeage du réservoir. Calculer les corrections dues à la charge hydrostatique du liquide
en suivant l'ISO 7507-1.
Tableau 1 — Compressibilité des hydrocarbures — Changement volumique en pourcentage
par 100 kPa de pression
Température
Masse volumique
à 15 °C
°C
kg/m
–15 0 15 30
900 0,005 3 % 0,005 8 % 0,006 3 % 0,006 8 %
850 0,006 0 % 0,006 6 % 0,007 2 % 0,007 9 %
800 0,007 0 % 0,007 7 % 0,008 6 % 0,009 5 %
750 0,008 3 % 0,009 3 % 0,010 % 0,012 %
Annexe A
(normative)
Corrections pour les effets thermiques
A.1 Facteurs de correction du volume
A.1.1 Jaugeage lorsque l’eau est le liquide de jaugeage
Lorsque l’eau est le liquide de jaugeage utilisé, le facteur de correction, C ,qu’il faut appliquer pour compenser les
fw
effets des différences en température du liquide entre le compteur et le réservoir jaugé, est fondé sur le rapport de
la masse volumique de l’eau aux deux températures mesurées.
Le facteur de correction, C , est obtenu par l’équation suivante:
fw
�
t1
C � (A.1)
fw
�
t2
où
ρ est la masse volumique de l’eau à la température de l’eau au compteur (t );
t1 1
ρ est la masse volumique de l’eau à la température de l’eau dans le réservoir jaugé (t ).
t2 2
NOTE C est le facteur de correction pour tenir compte de la différence de température entre l’eau dans le compteur et
fw
l’eaudansleréservoir jaugé; ce facteur de correction ne corrige pas le volume à 15 °Cou à 20 °C.
L'équation suivante doit être utiliséepour déterminer la masse volumique de l'eau pure, exempte d'air, �,en
t
o o
kilogrammes par mètre cube, à la température t entre 1 Cet40 C(voir note 2):
23 45
��
����1 At�t�Btt� �Ct�t �Dtt� �Et�t (A.2)
�� � � �� �� � �
t00 0 0 0 0
� �
��
��
où
� est la masse volumique de l'eau, en kilogrammes par mètre cube;
t
� est la masse volumique de l'eau à la température t ;
0 0
o
t est la température (3,981 8 C) à laquelle l'eau atteint sa masse volumique maximale;
t est la température du fluide, en degrés Celsius;
o
–8 –1
A est un coefficient polynomial égal à 7,013 4 �10 C ;
o
–6 –2
B est un coefficient polynomial égal à 7,926 504�10 C ;
o
–8 –3
C est un coefficient polynomial égalà–7,575 677 �10 C ;
o
–10 –4
D est un coefficient polynomial égal à 7,314 894�10 C ;
o
–12 –5
E est un coefficient polynomial égalà–3,596 458 �10 C ;
Les résultats de l'équation doivent être arrondis avec trois décimales.
12 © ISO 2001 – Tous droits réservés
NOTE 2 Les valeurs de la masse volumique sont basées sur la référence [8]. L'équation est valable dans l'étendue de
o o
température de 1,0 C à 40 C, telle que mesuréesur l'Échelle internationale de température de 1990, ITS-90.
Si l'eau utiliséepour l'étalonnage est saturée d'air, on doit appliquer une correction de la masse volumique de l'eau
mesuréeselonl'équation (A.2), avant l'arrondissage, au moyen de l'équation suivante:
�33
Correction����4,612� 0,10t �10 kg/m (A.3)
w
où t est la température de l'eau.
w
La masse volumique de l'eau corrigée doit être arrondie avec quatre décimales.
o o
NOTE 3 L'équation (A.3) est tirée delaréférence [9] pour l'eau dans l'étendue de température de 0 C à 25 C. Pour les
o
besoins de la présente Norme internationale, cette équation s'applique aux températures de l'eau jusqu'à (et y compris) 40 C.
Toute erreur d'étalonnage du réservoir due à l'utilisation de l'équation dans une plus large étendue de température peut s'avérer
insignifiante.
Tableau A.1 — Masse volumique de l'eau exempte d'air, en kilogrammes par mètre cube, en fonction de la
température en degrés Celsius sur l'Échelle internationale de température de 1990
Température Correction
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9
����C pour l’air
1 999,9012 999,9061 999,9108 999,9153 999,9196 999,9237 999,9277 999,9316 999,9352 999,9387 – 0,0045
2 999,9420 999,9451 999,9481 999,9509 999,9536 999,9560 999,9583 999,9605 999,9625 999,9643 – 0,0043
3 999,9659 999,9674 999,9688 999,9699 999,9709 999,9718 999,9724 999,9730 999,9733 999,9735 – 0,0042
4 999,9736 999,9735 999,9732 999,9728 999,9722 999,9714 999,9705 999,9695 999,9683 999,9669 – 0,0041
5 999,9654 999,9637 999,9619 999,9599 999,9578 999,9555 999,9530 999,9504 999,9477 999,9448 – 0,0040
6 999,9418 999,9386 999,9352 999,9317 999,9281 999,9243 999,9204 999,9163 999,9121 999,9077 – 0,0039
7 999,9032 999,8985 999,8937 999,8888 999,8837 999,8784 999,8730 999,8675 999,8618 999,8560 – 0,0038
8 999,8500 999,8439 999,8377 999,8313 999,8248 999,8181 999,8113 999,8044 999,7973 999,7901 – 0,0037
9 999,7827 999,7753 999,7676 999,7599 999,7519 999,7439 999,7357 999,7274 999,7190 999,7104 – 0,0036
10 999,7017 999,6928 999,6838 999,6747 999,6654 999,6561 999,6465 999,6369 999,6271 999,6172 – 0,0035
11 999,6072 999,5970 999,5867 999,5762 999,5657 999,5550 999,5442 999,5332 999,5221 999,5109 – 0,0034
12 999,4996 999,4881 999,4765 999,4648 999,4530 999,4410 999,4289 999,4167 999,4043 999,3919 – 0,0033
13 999,3793 999,3665 999,3537 999,3407 999,3276 999,3144 999,3011 999,2876 999,2740 999,2603 – 0,0032
14 999,2465 999,2326 999,2185 999,2043 999,1900 999,1756 999,1611 999,1464 999,1316 999,1167 – 0,0031
15 999,1017 999,0865 999,0713 999,0559 999,0404 999,0248 999,0091 998,9932 998,9773 998,9612 – 0,0030
16 998,9450 998,9287 998,9123 998,8958 998,8791 998,8624 998,8455 998,8285 998,8114 998,7942 – 0,0029
17 998,7768 998,7594 998,7418 998,7242 998,7064 998,6885 998,6705 998,6524 998,6342 998,6158 – 0,0028
18 998,5974 998,5788 998,5602 998,5414 998,5225 998,5035 998,4844 998,4652 998,4459 998,4265 – 0,0027
19 998,4069 998,3873 998,3675 998,3477 998,3277 998,3076 998,2875 998,2672 998,2468 998,2263 – 0,0025
20 998,2057 998,1850 998,1642 998,1433 998,1222 998,1011 998,0799 998,0586 998,0371 998,0156 – 0,0024
21 997,9939 997,9722 997,9503 997,9284 997,9063 997,8842 997,8619 997,8396 997,8171 997,7945 – 0,0023
22 997,7719 997,7491 997,7262 997,7033 997,6802 997,6570 997,6338 997,6104 997,5870 997,5634 – 0,0022
23 997,5397 997,5160 997,4921 997,4681 997,4441 997,4199 997,3957 997,3713 997,3469 997,3223 – 0,0021
24 997,2977 997,2729 997,2481 997,2232 997,1981 997,1730 997,1478 997,1225 997,0971 997,0715 – 0,0020
25 997,0459 997,0202 996,9944 996,9686 996,9426 996,9165 996,8903 996,8641 996,8377 996,8112 – 0,0019
26 996,7847 996,7581 996,7313 996,7045 996,6776 996,6506 996,6235 996,5963 996,5690 996,5416 – 0,0018
27 996,5141 996,4865 996,4589 996,4311 996,4033 996,3754 996,3474 996,3192 996,2910 996,2627 – 0,0017
28 996,2344 996,2059 996,1773 996,1487 996,1199 996,0911 996,0622 996,0332 996,0041 995,9749
...
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