EN ISO 8222:2020

SLOVENSKI STANDARD
01-junij-2020
Nadomešča:
SIST EN ISO 8222:2003
Naftni merilni sistemi - Umerjanje - Volumetrični ukrepi, rezervoarji in terenski
ukrepi (vključno s formulami za lastnosti tekočin in materialov) (ISO 8222:2020)
Petroleum measurement systems - Calibration - Volumetric measures, proving tanks and
field measures (including formulae for properties of liquids and materials) (ISO
8222:2020)
Messsysteme für Mineralölerzeugnisse - Kalibrierung - Temperaturkorrekturen zur
Anwendung auf volumetrische Bezugsmessbehälter (ISO 8222:2020)
Systèmes de mesure du pétrole - Étalonnage - Contenants de mesure volumétriques,
jauges étalons et contenants de mesure de travail (y compris les formules relatives aux
propriétés des liquides et des matériaux) (ISO 8222:2020)
Ta slovenski standard je istoveten z: EN ISO 8222:2020
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.

EN ISO 8222
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2020
EUROPÄISCHE NORM
ICS 75.180.30 Supersedes EN ISO 8222:2002
English Version
Petroleum measurement systems - Calibration -
Volumetric measures, proving tanks and field measures
(including formulae for properties of liquids and
materials) (ISO 8222:2020)
Systèmes de mesure du pétrole - Étalonnage - Messsysteme für Mineralölerzeugnisse - Kalibrierung -
Contenants de mesure volumétriques, jauges étalons et Temperaturkorrekturen zur Anwendung auf
contenants de mesure de travail (y compris les volumetrische Bezugsmessbehälter (ISO 8222:2020)
formules relatives aux propriétés des liquides et des
matériaux) (ISO 8222:2020)
This European Standard was approved by CEN on 17 February 2020.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 8222:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 8222:2020) has been prepared by Technical Committee ISO/TC 28 "Petroleum
and related products, fuels and lubricants from natural or synthetic sources" in collaboration with
Technical Committee CEN/TC 19 “Gaseous and liquid fuels, lubricants and related products of
petroleum, synthetic and biological origin.” the secretariat of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by October 2020, and conflicting national standards shall
be withdrawn at the latest by October 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 8222:2002.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 8222:2020 has been approved by CEN as EN ISO 8222:2020 without any modification.

INTERNATIONAL ISO
STANDARD 8222
Third edition
2020-03
Petroleum measurement systems —
Calibration — Volumetric measures,
proving tanks and field measures
(including formulae for properties of
liquids and materials)
Reference number
ISO 8222:2020(E)
©
ISO 2020
ISO 8222:2020(E)
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

ISO 8222:2020(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and units . 1
3.1 Terms and definitions . 1
3.2 Symbols and units . 8
4 Traceability . 9
5 General design characteristics of volumetric measures .10
5.1 General design .10
5.2 Design to indicate the volume — Resolution .12
5.2.1 Neck size .12
5.2.2 Gauge glass .12
5.2.3 Scales .13
5.2.4 Adjustment of scale and calibrated volume.15
5.2.5 Levelling .15
5.3 Additional design aspects .15
5.3.1 Temperature measurement .15
5.3.2 Valves and connections .16
5.3.3 Size of measures .17
5.4 Filling and drainage .18
5.4.1 Drainage times and fluids .18
5.4.2 Filling and drainage methods .19
5.5 Markings .20
6 Test measures .21
6.1 Overview .21
6.2 Design and construction of test measures .23
7 Proving tanks .24
7.1 Overview .24
7.2 General construction .28
7.3 Bottom neck .28
7.4 Strength .29
7.5 Support .29
7.6 Size .29
7.7 Mobility .29
7.8 Overflow and vapour recovery .29
7.9 Filling and drainage .29
8 Alternative designs .30
8.1 High-accuracy designs .30
8.2 Automatic pipettes.30
8.3 Proving tanks with bottom sight gauge .30
9 Calibration .31
9.1 General .31
9.2 Common calibration procedures .31
9.3 Gravimetric calibration .33
9.3.1 Principle .33
9.3.2 Calibration circuit and equipment .33
9.3.3 Procedure for calibrating a measure gravimetrically .34
9.4 Volumetric calibration .34
9.4.1 Principle .34
9.4.2 Calibration circuit and equipment .35
ISO 8222:2020(E)
9.4.3 Procedure for calibrating a measure volumetrically (water pour) .36
9.4.4 Procedure for calibrating a measure volumetrically (water withdraw) .36
9.4.5 Additional notes on procedures .37
9.5 Calibration by reference meter .38
9.5.1 Principle .38
9.5.2 Calibration circuit .38
9.5.3 Equipment .39
9.5.4 Procedure for calibration by reference meter .40
9.6 Calibration of neck scales .40
10 Calculations.41
10.1 Overview .41
10.2 Reference volume .41
10.3 Transferred volume (volumetric method) .42
10.4 Transferred volume (gravimetric method) .43
10.5 Calibrated volume of test device .44
10.6 Multiple fills .45
10.7 Calibration of a measure using a reference measure .45
10.8 Calibration of a flowmeter using a measure as reference .46
10.9 Calibration of a displacement (pipe) prover using a measure as reference .46
11 Calibrating and setting the neck and scale .46
11.1 Calibrating the neck .46
11.2 Setting the scales .47
12 Safety .48
Annex A (informative) Properties of fluids and materials .49
Annex B (informative) Temperature measurement and thermometers .63
Annex C (informative) Standard glass contents measures .65
Annex D (informative) Meniscus reading .66
Annex E (informative) Accuracy and uncertainty of volumetric measures .67
Bibliography .68
iv © ISO 2020 – All rights reserved

ISO 8222:2020(E)
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see
www .iso .org/ iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 28, Petroleum and related products, fuels
and lubricants from natural or synthetic sources, Subcommittee SC 2, Measurement of petroleum and
related products, in collaboration with the European Committee for Standardization (CEN) Technical
Committee CEN/TC 19, Gaseous and liquid fuels, lubricants and related products of petroleum, synthetic
and biological origin, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 8222:2002), which has been technically
revised. The main changes to the previous edition are as follows:
— revision of the title and scope to allow the document to cover the design, calibration and use of a
wide range of volumetric measures comprising proving tanks, test measures, field and standard
measures;
— provision of revised, updated and extended formulae to allow calculation of temperature correction
including the addition of formulae for saline water, other liquids and material properties.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
ISO 8222:2020(E)
Introduction
Volumetric, or capacity, measures are used to provide an accurate measure of volume, thereby providing
a calibration reference for other volume-measuring devices, such as pipe displacement provers or
flowmeters.
Volume measures are categorized in terms of capacity, test measures being below 20 l. Measures
above 20 l are categorised as prover tanks. Standard measures are designed to comply with regulatory
guidance and hence have specified volumes. Other measures have non-standard volumes specifically
designed to suit an application, for example measures to accompany a small volume prover.
Volumetric measures can be used to calibrate flowmeters, both duty and reference meters. They can
also be used to calibrate secondary volume measures, displacement (pipe) provers and storage tanks.
Annex A provides the recommended formulae used in the calibration and use of volumetric measures
and for other volumetric measurements. This includes pure and saline water properties, the properties
of hydrocarbon liquids and the materials of construction of volumetric measuring devices.
vi © ISO 2020 – All rights reserved

INTERNATIONAL STANDARD ISO 8222:2020(E)
Petroleum measurement systems — Calibration —
Volumetric measures, proving tanks and field measures
(including formulae for properties of liquids and
materials)
WARNING — The use of this document could involve hazardous materials, operations and
equipment. This document does not purport to address all of the safety problems associated
with its use. It is the responsibility of the user of this document to establish appropriate safety
and health practices.
1 Scope
This document describes the design, use and calibration of volumetric measures (capacity measures)
which are intended for use in fixed locations in a laboratory or in the field. This document gives
guidance on both standard and non-standard measures. It also covers portable and mobile measures.
This document is applicable to the petroleum industry; however, it may be applied more widely to other
applications.
This document excludes measures for cryogenic liquids and pressurized measures as used for liquid
petroleum gas (LPG) and liquefied natural gas (LNG).
Volumetric measures are classified as test measures or prover tanks depending on capacity and design.
Measures described in this document are primarily designed, calibrated and used to measure volumes
from a measure which is wetted and drained for a specified time before use and designated to deliver.
Many of the provisions, however, apply equally to measures which are used to measure a volume using
a clean and dry measure and designated to contain.
Guidance is given regarding commonly expected uncertainties and calibration specifications.
The document also provides, in Annex A, reference formulae describing the properties of water and
other fluids and materials used in volumetric measurement more generally.
2 Normative references
There are no normative references in this document.
3 Terms, definitions, symbols and units
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
ISO 8222:2020(E)
3.1.1
accuracy
closeness of the agreement between a measured quantity value and a true quantity value of a measurand
Note 1 to entry: The concept ‘measurement accuracy’ is not a quantity and should not be given a numerical value.
The quantitative expression of accuracy should be in terms of uncertainty. “Good accuracy” or “more accurate”
implies small measurement error. Any given numerical value should be taken as indicative of this.
[SOURCE: VIM: 2012, 2.13]
3.1.2
adjustment
set of operations carried out on a measuring system so that it provides prescribed indications
corresponding to given values of a quantity to be measured
Note 1 to entry: Adjustment should not be confused with calibration, which is a prerequisite for adjustment.
Note 2 to entry: After adjustment, a recalibration is usually required.
[SOURCE: VIM: 2012, 3.11]
3.1.3
automatic pipette
overflow pipette
high precision measure, where the volume withdrawn is defined by a top overflow weir rather than a
gauge scale
3.1.4
brim measure
field measure where the volume is defined by an overflow from the top edge of the neck
3.1.5
calibration
operation that, under specified conditions, in a first step, establishes a relation between the quantity
values with measurement uncertainties provided by measurement standards and corresponding
indications with associated measurement uncertainties and in a second step uses this information to
establish a relation for obtaining a measurement result from an indication
Note 1 to entry: A simplified definition is 'set of operations that establish, under specified conditions, the
relationship between quantities indicated by an instrument and the corresponding values realized by standards'.
Note 2 to entry: Calibration should not be confused with adjustment of a measuring system.
Note 3 to entry: The word “proving” is used in the oil industry and has the same meaning but can include a check
of the results against specified acceptance criteria.
[SOURCE: VIM: 2012, 2.39]
3.1.6
calibrated volume
volume of a measure between a top and bottom datum as determined by calibration and expressed at a
standard temperature
3.1.7
clingage
film of liquid that adheres to the inside surface of a volumetric measure after it has been emptied,
resulting in a residual volume
2 © ISO 2020 – All rights reserved

ISO 8222:2020(E)
3.1.8
correction factor
numerical factor by which the uncorrected result of a measurement at the measured conditions is
multiplied
Note 1 to entry: Correction factors to standard conditions are used to convert a volume at observed conditions to
the volume at another (standard) condition.
3.1.9
plunger
displacement plunger
device consisting of a piston which is used for adjusting the volume of a volumetric measure
3.1.10
drain time
total time taken to empty the measure or tank to leave a consistent residual volume
Note 1 to entry: Drain time commences when the drain valve is opened and ceases when closed after a defined
time or condition. Drain time may be divided into two parts: first drain time and final drain time.
Note 2 to entry: A dry measure can be employed where the product evaporates quickly, for example petrol.
These measures will not have a drain time and the means to ensure they are dry will be specified in documents
regulating their use.
3.1.11
final drain time
time which follows the cessation of the first drain time and finishes at a defined time, or condition, such
as rate of dripping
3.1.12
first drain time
time to drain the majority of the fluid from the measure
Note 1 to entry: The first drainage flow commences when the drain valve is opened and ends at a defined level,
time or when flow breaks into a defined trickle or drip rate. This is prior to the start of the final drain time.
3.1.13
dry measure
contents measure which is calibrated and used with the internal surface completely dry (i.e. no clingage
or residual volume)
Note 1 to entry: The volume of a dry measure may be marked and designated to contain.
3.1.14
error
measured quantity value minus a reference quantity value
Note 1 to entry: Note1 to entry: Relative error is error divided by a reference value. This can be expressed as a
percentage.
[SOURCE: VIM: 2012, 2.16]
3.1.15
field measure
measure designed to be used in the regular calibration of other devices
Note 1 to entry: While most field measures are portable, some can be in a fixed location.
ISO 8222:2020(E)
3.1.16
gauge glass
clear tube in parallel with, or a window set into, the neck of a measure to show the level of liquid in
the neck
Note 1 to entry: There is an associated scale to indicate the measured volume.
3.1.17
nominal volume
design volume of a volumetric measure
3.1.18
primary measure
reference measure calibrated gravimetrically
Note 1 to entry: Primary measures should be calibrated by a national measurement institute (NMI) or a
competent laboratory meeting ISO/IEC 17025.
3.1.19
proving
calibration with comparison to defined acceptance criteria
Note 1 to entry: The term “proving” is used in the oil industry and is similar to verification.
Note 2 to entry: Proving is a calibration, sometimes of limited measurement range, according to methods defined
by standards, regulations or procedures, providing a determination of the errors of a device and showing
(proving) it performs to defined acceptance criteria.
3.1.20
proving tank
volumetric measure which generally has capacity greater than 20 l and has a bottom drain
Note 1 to entry: A prover tank can be free-standing or mounted on a truck or trailer.
3.1.21
pour
individual quantities of liquid poured from, or received into, a volumetric measure
3.1.22
range
range of values
difference between the maximum and minimum values of a set of values
Note 1 to entry: This can be expressed as a half range (±) number. Relative range is normally expressed as a
percentage of a specified value, for example mean, minimum or other calculated value.
3.1.23
reference conditions
operating conditions prescribed for evaluating the performance of the measure
Note 1 to entry: This is the range of ambient and fluid conditions with which the measure is evaluated, verified
or operated.
3.1.24
reference measure
volumetric measure calibrated, used and maintained to provide traceability to other volume measures
and devices, including pipe provers and reference flowmeters
Note 1 to entry: A reference measure can be calibrated gravimetrically (primary measure) or volumetrically by
means of a primary measure which itself has been calibrated gravimetrically.
4 © ISO 2020 – All rights reserved

ISO 8222:2020(E)
3.1.25
repeatability
measurement precision
closeness of agreement between indications or measured quantity values obtained by replicate
measurements under specified conditions
Note 1 to entry: Specified conditions normally implies the same reference, same conditions, same operators and
procedures and that the data are obtained sequentially over a short period of time.
Note 2 to entry: Repeatability can be expressed as the range (difference between the maximum and minimum)
values of error or K-factor. Alternatively, repeatability can be expressed as a function of the standard deviation
of the values.
Note 3 to entry: Dividing repeatability by the mean gives the relative value which can be expressed as a
percentage. It is noted some standards suggest dividing by the minimum value.
[SOURCE: VIM: 2012, 2.15]
3.1.26
residual volume
volume or quantity remaining in the measure after draining for the defined drain time
3.1.27
resolution
quantitative expression of the ability of an indicating device to distinguish meaningfully between
closely adjacent values of the quantity indicated
3.1.28
scale datum
fixed reference point or mark, established at manufacture or initial calibration, from which subsequent
adjustments to the scale can be referred
Note 1 to entry: This may be an engraved mark on the neck, or another defined fixed point such as a support
bracket. The location should be referenced on calibration certificates.
3.1.29
secondary measure
volumetric measure which is calibrated by a primary measure
3.1.30
standard condition
base condition
condition of temperature and pressure to which measurements of volume or density are referred to
standardize the quantity
Note 1 to entry: These are the specified values of the conditions to which the measured quantity is converted.
Note 2 to entry: For the petroleum industry, these are usually 15 °C, 20 °C or 60 °F and 101,325 kPa.
Note 3 to entry: Standard conditions can refer to the liquid or the volume of the measure. These may be different.
Note 4 to entry: Quantities of volume expressed at standard conditions may be indicated by prefixing the
3 3 3
volume unit by “S”, for example 4 Sm or 700 kg/Sm . This abbreviation is used in place of the unit m (standard
conditions) where there is limited space and there is no risk of confusion regarding the unit.
Note 5 to entry: Standard conditions should not be confused with the reference (operating) conditions prescribed
for evaluating the measure.
ISO 8222:2020(E)
3.1.31
standard measure
volumetric measure which is designed to meet the requirements of regulatory standards
Note 1 to entry: Examples of regulatory standards are OIML R 120, Measurement Instruments Directive (MID)
and NIST 105-3.
3.1.32
standard volume
base volume
volume expressed as being at standard conditions
3.1.33
strike measure
brim measure where the volume is defined from the top edge of the neck which has been designed to be
struck by sliding a ground glass disk over it to leave a consistent volume within the measure
3.1.34
test measure
hand portable volumetric measure up to 20 l capacity
Note 1 to entry: A test measure can be inverted to drain or be fitted with a bottom drain.
Note 2 to entry: A test measure can also be non-portable, in a fixed frame or on a vehicle. It may in some cases be
classified as a prover tank.
3.1.35
thermowell
metal pocket which protrudes through, or is attached to, the wall of a pipe or volumetric measure to
hold a temperature-measuring device
3.1.36
volume to contain
standard volume of liquid a measure contains with respect to its reference line or datum when filled
from a clean dry condition
3.1.37
volume to deliver
standard volume of liquid which can be withdrawn from or filled into a pre-wetted measure with
respect to its reference line or datum and following specified drainage times and procedures
Note 1 to entry: A wet condition is obtained by filling the measure and draining it for the specified drain time and
procedure.
Note 2 to entry: The volume to deliver is always less than the volume to contain due to the volume of residual
liquid left on the walls of the measure after the specified drain time.
Note 3 to entry: A measure marked with a volume to deliver can be used either to withdraw or to fill volumes as
long as the wetting and drainage procedures are followed.
3.1.38
fill
receive
In
technique for using or calibrating a volumetric measure by filling from top or bottom with liquid from
the device under test or the reference
Note 1 to entry: The reference may be volumetric or gravimetric.
[2]
Note 2 to entry: 'In' is the term adopted by EURAMET guide cg21 .
6 © ISO 2020 – All rights reserved

ISO 8222:2020(E)
3.1.39
withdraw
water draw
Ex
technique for using or calibrating a volumetric measure by withdrawing liquid from the measure into
the device under test or the reference
Note 1 to entry: The reference may be volumetric or gravimetric.
Note 2 to entry: 'Water draw' is usually applied to the calibration of pipe provers.
[2]
Note 3 to entry: 'Ex' is the term adopted by EURAMET guide cg21 .
3.1.40
traceability
metrological traceability
property of a measuring result whereby the result can be related to a reference through a documented
unbroken chain of calibrations, each contributing to the measurement uncertainty
[SOURCE: VIM: 2012, 2.41]
3.1.41
transfer point
point or location in a fluid transfer where the quantity and accountability of the fluid passes from one
measurement system to another
3.1.42
uncertainty
non-negative parameter characterizing the dispersion of the quantity values attributed to a measurand
based on the information used
[SOURCE: VIM: 2012, 2.26]
Note 1 to entry: The uncertainty is normally expressed as a half width range along with the probability
distribution with that range. It can be expressed as a value or as a percentage of the perceived true value.
3.1.43
volumetric measure
measure used to provide an accurate measure of a volume, hence providing a calibration reference for
other volume-measuring devices, such as pipe displacement provers or flowmeters
3.1.44
water pour
technique for calibrating a measure by decanting liquid from a reference measure or a gravimetric
system to a device under test
3.1.45
wet measure
volumetric measure which has been wetted and drained before use in accordance with defined drain
times and procedures given in the calibration certificate and specification
3.1.46
wetted
portion of the internal surface of a volumetric measure which has been in contact with the liquid
during use
3.1.47
weir
device, usually a horizontal edge, where a consistent liquid level is established to provide a datum
ISO 8222:2020(E)
3.2 Symbols and units
NOTE 1 The preferred unit for kinematic viscosity is metres squared per second (m /s) or millimetres squared
per second (mm /s). The practical unit used in this document is the industry-recognized unit centistoke (cSt);
1 cSt = 1 mm /s.
NOTE 2 The preferred unit for a volume expressed at a standard condition is m (standard condition). In
practice this is conventionally abbreviated to Sm where there is limited space and there would be no confusion
of units used.
Symbol Quantity Unit
C volume correction factor for thermal expansion of liquid from measured tem-
tl
perature to the standard temperature
C volume correction factor for thermal expansion of liquid from reference de-
dtl
vice (measure) temperature to the temperature at the device under test
C volume correction factor for thermal expansion of liquid from reference de-
tlr
vice (measure) temperature to the standard temperature
C volume correction factor for thermal expansion of liquid from test device
tlt
temperature to the standard temperature
C volume correction factor for liquid compressibility from measured pressure
pl
to standard pressure
C volume correction factor for liquid compressibility from pressure to standard
plt
pressure from a device under test
C volume correction factor for the thermal expansion of the device (material) to
ts
volume at standard temperature
C volume correction factor for the thermal expansion of the reference measure
tsr
material to the volume at standard temperature
C volume correction factor for the thermal expansion of the device under test
tst
material to the volume at standard temperature
C volume correction factor for the pressure expansion of the device under test
ps
to the volume at standard pressure
F meter factor of a flowmeter at operating temperature and pressure
M mass of water collected in weigh container kg
t temperature of the liquid in the reference device °C
r
t temperature of the liquid in the device under test °C
t
t standard temperature for the reference measure °C
sr
t standard temperature of the device under test °C
st
V indicated volume from a flowmeter at actual conditions m or l
m
V volume measured by a reference, measure or flowmeter, at actual conditions m or l
r
of pres
...