OIML R - 18 Mass Flow Meter

INTERNATIONAL OIML R 81
RECOMMENDATION Edition 1998 (E)
Dynamic measuring devices and systems

for cryogenic liquids
Dispositifs et systèmes de mesure dynamique de liquides cryogéniques

OIML R 81 Edition 1998 (E)
ORGANISATION INTERNATIONALE
DE MÉTROLOGIE LÉGALE
INTERNATIONAL ORGANIZATION
OF LEGAL METROLOGY
OIML R 81: 1998 (E)
Contents
Foreword ....................................................................................................................................................................... 3
SECTION I - GENERAL
1 Scope .................................................................................................................................................................. 4
2 Application ......................................................................................................................................................... 4
3 Terminology ....................................................................................................................................................... 4
4 Principles of the Recommendation .................................................................................................................. 7
5 Units of measurement ....................................................................................................................................... 7
SECTION II - METROLOGICAL REQUIREMENTS
6 Maximum permissible errors (mpe) ................................................................................................................. 7

7 Flowrates of a measuring system or a meter ................................................................................................... 7
8 Minimum measured quantity ........................................................................................................................... 7
SECTION III - TECHNICAL REQUIREMENTS
9 Indicating devices (indicators) ......................................................................................................................... 8

10 Printing devices (printers) ................................................................................................................................. 8
11 Measuring systems ............................................................................................................................................ 8
12 Discharge lines and valves ................................................................................................................................ 9
13 Markings .......................................................................................................................................................... 10
SECTION IV - MEASURING SYSTEMS EQUIPPED WITH ELECTRONIC DEVICES
14 Measuring systems equipped with electronic devices ................................................................................... 10
SECTION V - METROLOGICAL CONTROLS
15 General requirements ...................................................................................................................................... 12

16 Test conditions ................................................................................................................................................. 16
Annex A Test procedures. Performance tests - general .......................................................................................... 18

Annex B Test procedures. Performance tests - applicable to electronic equipment ............................................ 20
Annex C Tables of density for liquid argon, helium, hydrogen, nitrogen and oxygen; References ..................... 27
Bibliography ................................................................................................................................................................ 48
Printed in France GRANDE IMPRIMERIE DE TROYES

130, rue Général-de-Gaulle, 10000 Troyes
OIML R 81: 1998 (E)
Foreword
T
he International Organization of Legal Metrology of avoiding contradictory requirements; consequently,
(OIML) is a worldwide, intergovernmental organization manufacturers and users of measuring instruments, test
whose primary aim is to harmonize the regulations laboratories, etc. may apply simultaneously OIML publica-
and metrological controls applied by the national metro- tions and those of other institutions.
logical services, or related organizations, of its Member
International Recommendations and International Docu-
States.
ments are published in French (F) and English (E) and are
The two main categories of OIML publications are: subject to periodic revision.
• International Recommendations (OIML R), which are This publication - reference OIML R 81, edition 1998 (E) -
model regulations that establish the metrological was developed by the OIML subcommittee TC 8/SC 6
characteristics required of certain measuring instruments Measurement of cryogenic liquids. It was approved for final
and which specify methods and equipment for checking publication by the International Committee of Legal Metro-
their conformity; the OIML Member States shall imple- logy in 1997 and will be submitted to the International
ment these Recommendations to the greatest possible Conference of Legal Metrology in 2000 for formal sanction.
extent; It supersedes the previous edition dated 1989.
• International Documents (OIML D), which are inform-
ative in nature and intended to improve the work of the OIML publications may be obtained from the Organization’s
metrological services. headquarters:
OIML Draft Recommendations and Documents are

developed by technical committees or subcommittees which
Bureau International de Métrologie Légale
are formed by the Member States. Certain international and
11, rue Turgot - 75009 Paris - France
regional institutions also participate on a consultation basis.
Telephone: 33 (0)1 48 78 12 82 and 42 85 27 11
Cooperative agreements are established between OIML and Fax: 33 (0)1 42 82 17 27
certain institutions, such as ISO and IEC, with the objective E-mail: biml@oiml.org
3
OIML R 81: 1998 (E)
Dynamic measuring devices and systems

for cryogenic liquids
Section I 3.1 Cryogenic liquid
GENERAL A fluid with a boiling point of less than 120 K (–153 °C)
under atmospheric pressure conditions, which has
been liquefied by refrigeration.
1 Scope
3.2 Normal boiling point
This Recommendation prescribes the metrological and
technical requirements and test procedures for meas- That temperature at which a liquid vaporizes or boils
uring devices and systems used for the dynamic meas- at the atmospheric pressure of 101 325 Pa.
urement of cryogenic liquids.
This Recommendation establishes the conditions that 3.3 Reference (or working) standard
measuring devices and systems shall meet to comply
with the requirements of legal metrology services. A standard, traceable to national standards, used for
the verification of cryogenic liquid measuring devices
and systems.
Note: This is usually referred to as “master meter” in

this field.
2 Application
2.1 This Recommendation applies to devices used 3.4 Measuring system

for the measurement of cryogenic liquids such as, but A system that is comprised of the meter itself and all
not limited to oxygen, nitrogen, hydrogen, and argon. the ancillary devices and other equipment assembled
In principle, this Recommendation applies specifically to carry out the specified measurement task.
for the quantitative measurements of cryogenic liquids
whether installed in a permanent location, or mounted
for use in transport and/or other containment vessels 3.5 Meter
or tanks.
An instrument designed to measure continuously,
2.2 This Recommendation does not apply to the memorize and display the quantity that passes through
following: the measurement transducer.
• Devices used for dispensing liquefied petroleum Note: A meter includes at least a measurement trans-
gases (see OIML R 117 (1995) Measuring systems for ducer, a calculator (including adjustment or
liquids other than water); correction devices if present), a conversion
• Mass flow meters (see OIML R 105 (1993) Direct device (if necessary), and an indicating device.
mass flow measuring systems for quantities of liquids).
3.6 Measurement transducer
A part of the meter that transforms the flow of the

liquid to be measured into a signal(s) which is (are) sent
3 Terminology to the calculator. It may either be autonomous or use
an external power source.
The vocabulary provided below has been selected so Note: For the purpose of this Recommendation, the
that frequently used terms relating to cryogenic liquid measurement transducer includes the flow or
measuring systems will be clearly defined. volume sensor.
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OIML R 81: 1998 (E)
3.7 Calculator 3.13 Minimum measured quantity of a

measuring system
A part of the meter that receives the output signal
from the transducer(s), transforms it and, if ap- The smallest quantity of liquid for which the measure-
propriate, stores in memory the results until they are ment is metrologically acceptable.
used. Additionally, the calculator may be capable of
communicating both ways with the peripheral equip- Note: In a measuring system intended to deliver, this
ment. quantity is called the minimum delivery, and in
those used for receiving operations it is called the
minimum receipt.
3.8 Indicating device
A part of the meter that is capable of displaying con- 3.14 Scale interval
tinuously the measurement results.
The difference between the scale values corresponding
Note: A printing device that provides an indication at to two successive scale marks.
the end of the measurement is not an indicating
device.
3.15 Pre-setting device
3.9 Ancillary device A device that permits the selection of the quantity to
A device intended to perform a particular function, be measured and which automatically stops the flow
directly involved in elaborating, memorizing, transmit- of the liquid at the end of the measurement and
ting or displaying the measurement result. Examples delivery of the selected quantity.
are a printing device or a remote indicator.
3.16 Metering conditions
3.10 Correction device
The conditions of the volume of the liquid at the point
A device connected to or incorporated in the meter for of measurement. For example, temperature and pres-
automatically correcting the volume in metering sure.
conditions, by taking account of the flowrate and/or
the characteristics of the liquid to be measured (vis-
cosity, temperature, pressure, etc.) and pre-established 3.17 Base conditions
calibration curves.
The specified conditions of temperature and pressure
The characteristics of the liquid may either be meas- to which the measured volume is converted.
ured using associated measuring instruments, or
Note: Although the term “reference conditions” is
stored in a memory within the instrument.
often used instead of “base conditions”, meter-
ing and base conditions (that refer only to the
3.11 Conversion device volume of the liquid to be measured or indi-
cated), should not be confused with the “rated
A device that automatically converts the volume
operating conditions” and “reference condi-
measured at metering conditions into a volume at base
tions” that apply to influence quantities.
conditions or into a mass, by taking account of the
characteristics of the measured liquid (temperature,
pressure, density, relative density, etc.) using assoc- 3.18 Transfer point
iated measuring instruments, or associated values
stored in a memory. The point at which the quantity of liquid measured is
The quotient of the volume at base conditions, or of defined as being delivered or received.
the mass, to the volume at metering conditions is
referred to as the “conversion factor”. 3.19 Repeatability
3.12 Empty-hose type or dry-hose The ability of a measuring instrument to provide

closely similar indications for repeated applications of
A type of system in which the discharge hose is drained the same measurand under the same conditions of
after each delivery. measurement. [VIM 5.27]
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OIML R 81: 1998 (E)
3.20 Intrinsic error 3.26 Influence factor

The error of a measuring system under reference con- An influence quantity having a value within the rated
ditions. operating conditions of the measuring system, as
specified in this Recommendation.
3.21 Initial intrinsic error
3.27 Disturbance
The error of the instrument as determined prior to any
of the performance tests. An influence quantity having a value within the limits
specified in this Recommendation, but outside the
specified rated operating conditions of the measuring
3.22 Uncertainty in the determination of an error
system.
An estimate characterizing the range of values within
which the true value of an error lies, including com- 3.28 Rated operating conditions*
ponents due to the standard and its use, and com-
ponents due to the verified or calibrated instrument Conditions of use, specifying the range of values of
itself. influence quantities for which the metrological char-
acteristics are intended to be within the maximum
Note: The components due to a meter verified or permissible errors.
calibrated are notably linked to the resolution of
its indicating device and to the periodic varia- 3.29 Permanent automatic checking facility
tion. (type P)*
3.23 Fault* An automatic checking facility that operates during

the entire measurement operation.
The difference between the error of indication and the
intrinsic error of a measuring system. 3.30 Intermittent automatic checking facility
(type I)*
3.24 Significant fault* An automatic checking facility that operates at least
A fault the magnitude of which is greater than 20 % of once, either at the beginning or end of each measure-
the maximum permissible error (mpe) for the meas- ment operation.
ured quantity.
3.31 Nonautomatic checking facility
The following are not considered to be significant (type N)*
faults:
A checking facility that requires the intervention of an
• faults arising from simultaneous and mutually operator.
independent causes in the measuring instrument
itself or in its checking facility;
3.32 Reference conditions
• transitory faults being momentary variations in the
indication, that cannot be interpreted, memorized, A set of specified values of influence factors to ensure
or transmitted as a measurement result; valid inter-comparisons of the results of a measure-
• faults implying the impossibility of performing any ment.
measurement.
3.33 Performance test
3.25 Influence quantity*
A test to verify that the measuring system under test
A quantity that is not the subject of the measurement (EUT) is capable of accomplishing its intended func-
but that can influence the value of the measurand or tions.
the indication of the measuring system (VIM 2.7).
3.34 Primary indication
* Those definitions marked * are relevant to An indication (displayed, printed or memorized) that
electronic measuring systems only. is subject to legal metrology control.
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OIML R 81: 1998 (E)
Note: Indications other than primary indications are Section II

commonly referred to as secondary indications.
METROLOGICAL REQUIREMENTS
3.35 Direct selling to the public
6 Maximum permissible errors (mpe)
A transaction (selling or buying) of quantities of
liquids whose settlement is associated with indications
6.1 For pattern approval of a measuring system, the
provided by a measuring system, any of the parties
mpe is ± 2.5 % of the measured quantity.
having access to the place of measurement and one of
them being a consumer.
6.2 For pattern approval of a meter (3.5), the mpe is
Note: The consumer can be any person. Generally, the ± 1.5 % of the measured quantity.
consumer is the buyer but he can also be the
6.3 For pattern approval of components, the mpe is:
seller.
6.3.1 Temperature sensor: ± 1 K;
6.3.2 Pressure sensor: ± 50 kPa;
6.3.3 Density sensor: ± 5 kg/m3;
6.3.4 Measurement transducer (3.6):
± 1 % of measured quantity;
4 Principles of the Recommendation 6.3.5 For a calculator (3.7):
± 0.25 % of calculated quantity;
The determination of the accuracy of the measuring 6.3.6 For a conversion device (3.11):
devices and systems evaluated under this Recom- ± 1 % of converted quantity.
mendation is based either on the use of a gravimetric
6.4 For initial or subsequent verification of a meas-
test or the use of a master meter.
uring system under in-service conditions, the mpe is
± 2.5 % of the measured quantity.
6.5 Repeatability (3.19). The difference between the

5 Units of measurement largest and smallest results of successive measure-
ments shall not be greater than 1 % of the measured
quantity.
5.1 The measurement results may be indicated in
terms of:
• mass;
• liquid volume at the normal boiling point; or 7 Flowrates of a measuring system or a
• gas equivalent of a liquid volume at base conditions. meter
The indicated and recorded units shall be the kilo- 7.1 The maximum and minimum authorized flow-
gram, cubic metre or litre, or decimal multiples or rates for a measuring system are specified by the
sub-multiples thereof. manufacturer.
5.2 The density values given in the “Cryogenic 7.2 The ratio between the maximum and minimum
liquids density tables” (see Annex C) shall be used for flowrates of a meter shall be at least equal to 5.
volume-mass computations of liquid argon, helium,
hydrogen, nitrogen and oxygen. For other cryogenic
liquids, tables applicable under national legal metro-
logy authorities should be used. 8 Minimum measured quantity
8.1 The minimum measured quantity of the system

shall be specified by the manufacturer.
8.2 The minimum measured quantity shall not be
less than 100 scale intervals.
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OIML R 81: 1998 (E)
8.3 The value of the minimum measured quantity from that of the measurement which has just been
shall be in the form 1 × 10n or 2 × 10n or 5 × 10n made, until the zeroing operation has been completed.
authorized units, n being a positive or negative whole
number or zero. Indicating devices shall not be capable of being reset
to zero during measurement.
9.3 Totalizing indicator

Section III An indicator with a zeroing device may be equipped
with a device for totalizing the different quantities
TECHNICAL REQUIREMENTS
shown successively by the indicator.
Note: The totalizing indicator shall be non-resettable.
9 Indicating devices (indicators)
9.1 General provisions 10 Printing devices (printers)

Indications shall be in legal units as described in 5.1
10.1 A printing device may be connected to an
and shall be accompanied by the name or symbol of
indicator.
the unit. Indications that are not subjected to
metrological control are allowed, provided that they 10.2 The printed scale interval shall be the same as
cannot be confused with metrological information. the scale interval of the indicator.
Reading of the indications shall be precise, easy and 10.3 The quantity printed shall be expressed in one
non-ambiguous when the indicating device comes to of the units authorized for the indicator. The unit used
rest. If the indicating device comprises several elements, or its symbols, and the decimal mark if any, shall be
the installation shall be arranged in such a way that indicated on the ticket. The printed quantities shall be
the readings of the measurand can be effected by adequately and clearly defined.
simple juxtaposition of the indications of the different
elements. 10.4 The printer may print other information
identifying the measurement such as serial number,
9.1.1 The scale interval of the indication shall be in date, place of measurement, type of liquid, etc.
the form of 1 × 10n or 2 × 10n or 5 × 10n authorized
units, n being a positive or negative whole number or 10.5 If a printer allows repetition of the printing
zero. before a new measurement has started, copies shall be
clearly marked as such, for example by printing
9.1.2 The indicated units specified in subclause 5.1 “duplicate”.
shall be clearly defined.
10.6 For any quantity, the printed values shall be the
9.1.3 The decimal mark shall appear distinctly. same as those indicated.
10.7 Printed ticket. In the case of a volume indica-
9.2 Zero-setting device tion, the ticket shall have printed on it the base con-
ditions in terms of gas or liquid.
9.2.1 An indicating device may be provided with a
device which returns the indication to zero either by
manual operation or by automatic means.
9.2.2 The zero-setting device shall not permit any 11 Measuring systems
alteration of the measurement result shown by the
indicator (other than by making the result disappear 11.1 Maintenance of liquid state
and replacing it by zeros).
A measuring system shall be so designed and operated
9.2.3 Once the zeroing operation has begun it shall be that the product being measured will remain in a
impossible for the indicator to show a result different liquid state during passage through the meter.
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OIML R 81: 1998 (E)
11.2 Adjusting means 11.4.3 When the storage is full, memorized data may
be deleted when both the following conditions are
11.2.1 Meters shall be provided with adjusting means met:
that permit adjustments of the ratio between the
quantity indicated and the actual quantity of liquid • the rules established for the particular application
which has passed through the measuring device. are respected;
• data are deleted in the same order as the recording
11.2.2 If the adjusting means modifies this ratio in a order; and
discontinuous manner, the consecutive values of the
ratio shall not differ by more than 0.002. • deletion is carried out after a special manual
operation.
11.2.3 Adjustments by means of a by-pass on the meas-
uring device are prohibited. 11.4.4 Memorization shall be such that it is impossible
in normal use to modify stored values.
11.3 Sealing
Sealing means shall be provided for those parts that
can affect the accuracy of the measurement and for 12 Discharge lines and valves
the parameters (e.g. correction and conversion) that
can affect the measurement results.
12.1 Vapor return lines
11.3.1 Mechanical sealing
A vapor return line between the supplier’s tank and the
Mechanical sealing shall be carried out by means of customer’s tank shall not be permitted, unless neces-
lead and wire seals or other equally effective means. sary to complete a delivery.
11.3.2 Electronic sealing
12.2 Directional flow valve
When access to parameters that affect the determina-
A valve(s) or other means intended to prevent flow
tion of the results of a measurement is not protected
reversal, that is(are) automatic in operation shall be
by mechanical sealing means, the protection shall
installed either on the outlet side of the meter or in the
fulfill the following:
inlet line of the receiving tank.
• access shall only be possible by such means as an
alpha or numeric code, or “hard key”; 12.3 Diversion of measured liquid
• an event counter (000–999) shall be provided to
indicate that interventions have been made. No means shall be provided by which any measured
liquid can be diverted from the measuring element of
Note: The electronic sealing device should have a the meter or the discharge line therefrom. However, a
means of identifying if an intervention occurs manually controlled outlet that may be opened for
and by whom. The responsible national body purging or draining the measuring system shall be
may require such means as the use of labels or permitted. Effective means shall be provided to
an event logger that includes an event counter, prevent the passage of liquid through any such outlet
date and time of intervention, and the identity during normal operation of the measuring system.
and value of the parameter changed.
11.4 Memory devices 12.4 Transfer point

11.4.1 Measuring systems may be fitted with a memory 12.4.1 The measuring systems shall incorporate a
device to store measurement results until their use or transfer point. This transfer point shall be located
to keep a trace of commercial transactions, providing downstream of the meter in a delivery system, and
proof in case of dispute. Devices used to read stored
upstream of the meter in a receiving system.
information are considered as included in the memory
devices.
12.4.2 This transfer point may be in the form of a
11.4.2 The medium on which the data are stored shall closing device combined with a system which ensures
have sufficient permanency to ensure that the data are the evacuation of the discharge hose after each
not corrupted under normal storage conditions. measuring operation.
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OIML R 81: 1998 (E)
12.5 Valves and control mechanisms the maximum permissible errors as defined in clause 6
under rated operating conditions.
Check valves and closing mechanisms not used to
define the measuring quantity shall, if necessary, have 14.1.1.1 Interruptible electronic measuring systems
relief valves in order to dissipate any abnormally high shall be designed and manufactured such that, when
pressures which may arise in the measuring system. they are exposed to the disturbances specified in B.4,
either:
12.6 Discharge hose a) significant faults do not occur, or
b) significant faults are detected and acted upon by
The discharge hose of a measuring system shall be of
means of checking facilities. This provision may
the empty-hose type.
apply separately to each individual cause of signif-
icant fault and/or each part of the measuring
system.
14.1.1.2 Non-interruptible electronic measuring
systems shall be designed and manufactured in such a
13 Markings
way that no significant faults occur when they are
exposed to the disturbances specified in B.4.
A measuring system shall be legibly and clearly
marked with the following information: 14.1.2 It is the responsibility of the manufacturer to
decide whether a given pattern of measuring system is
• pattern approval mark; interruptible or not, taking account of the applicable
• manufacturer’s name or trademark; rules of security.
• accuracy class (designation selected by the manu-
facturer), if appropriate; 14.1.2.1 Measuring systems for direct selling to the
• serial number and year of manufacture; public shall be interruptible. When, at the time of
pattern approval, it is not possible to specify the future
• maximum and minimum flowrates Qmax and Qmin;
utilization of the instrument, the requirements in
• maximum pressure Pmax; subclause 14.1.1.2 apply.
• maximum and minimum temperature Tmax and
Tmin; 14.1.3 Electronic measuring systems shall be provided
• minimum measured quantity. with the checking facilities specified in subclause 14.3.
14.1.4 A pattern of a measuring system is presumed to
comply with the requirements in subclauses 14.1.1 and
14.1.3 if it passes the inspection and tests specified in
subclause 15.1.10.
Section IV 14.1.5 When a significant fault occurs, measuring

systems shall permit the retrieval of the information
MEASURING SYSTEMS EQUIPPED WITH relating to the measured quantity, that is contained
ELECTRONIC DEVICES within the measuring system.
14.2 Power supply device

When the flow is interrupted during a failure of the
14 Measuring systems equipped with principal power supply device:
electronic devices • the measuring system shall be provided with an
emergency power supply device to safeguard all the
measuring functions during that failure, or
14.1 General requirements
• data contained at the moment of the failure shall be
14.1.1 Electronic measuring systems shall be designed saved and displayed on the resumption of power on
and manufactured such that their errors do not exceed an indicating device subject to legal metrology
10
OIML R 81: 1998 (E)
control for sufficient time to permit the conclusion 14.3.2 Checking facilities for the measurement
of the current transaction. transducer
The absolute value of the maximum permissible error The object of these checking facilities after the
for the indicated volume in this case is increased by presence of the transducer has been confirmed, is to
5 % of the minimum measured quantity (subclause verify its correct operation and the correctness of data
8.1). transmission.
For all technologies, checking facilities shall provide a
level of security equivalent to ISO 6551, part 3 Levels
14.3 Checking facilities of security, 3.1.4 Level B, except for equipment with a
cable length of 3 meters or less, for which 3.1.3 Level
The checking facilities may either be permanent auto- C applies.
matic (type P), intermittent automatic (type I) or non
Note: This requirement can be fulfilled without gen-
automatic (type N) as appropriate.
erating two pulses.
14.3.1 Action of checking facilities 14.3.3 Checking facilities for the calculator
(Type P or I)
The detection by the checking facilities of significant
faults shall result in the following actions, according to The object of these checking facilities is to check if the
the type: calculator system functions correctly and to ensure the
validity of the calculations made.
14.3.1.1 Checking facilities of types I or P There are no special means required for indicating
that these checking facilities function correctly.
a) for non-interruptible measuring systems (such as
pipelines): The correct value of all data relating to the measure-
ment shall be checked by the instrument whenever
• automatic correction of the fault, or these data are transmitted to an ancillary device
• stopping only the faulty device when the measuring through an interface.
system without that device continues to comply with
the regulations, or In addition, the calculation system shall be provided
with a means for controlling the continuity of the
• a visible or audible alarm for the operator; this calculation program.
alarm shall continue until such time as the cause of
the alarm is suppressed. In addition, when the 14.3.4 Checking facility for the indicating device
measuring system transmits data to peripheral (Type N)
equipment, the transmission shall be accompanied
by a message indicating the presence of a fault. The object of this checking facility is to verify that the
primary indications are displayed and correspond to
Note: The third bullet point above is not applicable for the data provided by the calculator.
the disturbances specified in B.4.
In addition, it aims at verifying the presence of the
In addition, the instrument may be provided with indicating devices, when they are removable.
devices to estimate the amount of liquid having passed
through the installation during the occurrence of the The checking facility for the indicating device shall
fault. The result of this estimate shall not be capable of include at least a visual checking of the display as
being mistaken for a valid indication. follows:
• displaying all the elements (“eights” test);
b) for interruptible measuring systems: • blanking all the elements (“blank” test);
• automatic correction of the fault, or • displaying “zeros”.
• stopping only the faulty device, when the measuring Each step of the sequence shall last at least 0.75
system without that device continues to comply with second.
the regulations, or Note: The produced signal shall originate from the
• stopping the flow. calculator.
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OIML R 81: 1998 (E)
14.3.5 Checking facilities for an ancillary device constituent elements of a measuring system, mainly,
but not limited to, those listed below, and sub-systems
Any ancillary device with primary indications shall that may include more than one of these elements,
include a checking facility of type I or P. The object of may be subject to separate pattern approval:
this checking facility is to verify the presence of the
ancillary device, when it is a necessary device, and to • transducer;
validate the data transmitted by the calculator. • meter;
• electronic calculator (including the indicating
The object of the checking of a printing device is to
ensure that the printing controls function properly so device);
that output corresponds to the data transmitted by the • conversion device;
calculator. The presence of paper shall be checked. • devices providing or memorizing measurements
results;
Where the action of the checking facility is a warning,
• printer;
this shall be given on or by the ancillary device which
is at its origin. • temperature sensor;
• pressure sensor;
14.3.6 Checking facilities for the associated measuring • density sensor.
instruments
Associated measuring instruments shall include a 15.1.2 Documentation
checking facility of type P. The aim of this checking
facility is to ensure that the signal given by these 15.1.2.1 The application for pattern approval of a
associated instruments is within a pre-determined measuring system or of a constituent element of a
measuring range. measuring system shall include the following docu-
ments:
• description giving the technical characteristics and
the principle of operation;
• drawing or photograph;
Section V • a list of the components with a description of their
constituent materials. When this has a metrological
METROLOGICAL CONTROLS influence, an assembly drawing with identification
of different components, for measuring systems, the
references of the approval certificates of the con-
15 General requirements stituent elements, if any, for measuring systems and
meters fitted with correction devices, a description
The expanded uncertainty, U (for coverage factor of the way the correction parameters are de-
k = 2), for the reference standard (including its termined;
indicating device), shall be less than 1/5 of the • drawing showing the location of seals and verifica-
applicable maximum permissible errors of the tion marks;
measuring system under test for pattern approval and
• drawing of regulatory markings.
shall be less than 1/3 of the applicable maximum
permissible errors of the measuring system under test
15.1.2.2 In addition, the application for pattern
for other verifications. (See Guide to the Expression of
approval of an electronic measuring system shall
Uncertainty in Measurement, 1995).
include:
The reference standards and their use may be the
• a functional description of the various electronic
subject of other International Recommendations.
devices;
• a flow diagram of the logic, showing the functions
15.1 Pattern approval
of the electronic devices;
15.1.1 General • any document or evidence which shows that the
design and construction of the electronic measuring
Measuring systems subject to legal metrology control system comply with the requirements of this Re-
shall be subject to pattern approval. In addition, the commendation.
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OIML R 81: 1998 (E)
15.1.2.3 The applicant shall provide the body res- this body allows the modified instruments to be
ponsible for the evaluation with an instrument repres- presented for initial verification without granting a
entative of the final pattern. supplementary pattern approval certificate.
A new pattern approval has to be issued when the

15.1.3 Pattern approval certificate modified pattern no longer fulfills the provisions of the
The following information shall appear on the pattern previous pattern approval.
approval certificate:
• name and address of the recipient of the approval 15.1.5 Pattern approval of a meter or of a meas-
certificate; urement transducer
• name and address of the manufacturer, if it is not
the recipient; 15.1.5.1 A pattern approval may be given for a
• type and/or commercial designation; meter (3.5). It may also be given for the measurement
transducer (as defined in 3.6) separately when it is
• metrological and technical characteristics;
intended to be connected to different types of cal-
• pattern approval mark; culators.
• period of validity;
• environmental classification, if applicable (see The following examinations and tests shall be carried
Annex A); out on the meter alone or on the measurement
• information on the location of marks for pattern transducer when it is the subject of a separate ap-
approval, initial verification and sealing (for plication for pattern approval. They also may be
example, picture or drawing); carried out on the whole measuring system.
• list of documents which accompany the pattern
approval certificate; Normally, tests are carried out on the complete meter,
• specific remarks. fitted with an indicating device, with all the ancillary
devices and with the correction device, if any.
When applicable, the version of the metrological part
However, the meter subject to testing need not be
of the evaluated software shall be indicated in the
fitted with its ancillary devices when the latter are not
pattern approval certificate or in its annexes (technical such as to influence the accuracy of the meter and
file). when they have been verified separately (for example:
electronic printing device). The measurement trans-
15.1.4 Modification of an approved pattern ducer may also be tested alone provided the comput-
ing and indicating devices have been subject to
15.1.4.1 The recipient of the pattern approval shall separate pattern approvals. If this measurement
inform the body responsible for the approval of any transducer is intended to be connected to a calculator
modification or addition which concerns an approved fitted with a correction device, the correction algo-
pattern. rithm as described by the manufacturer shall be
applied to the output signal of the transducer to
15.1.4.2 Modifications and additions shall be sub- determine its errors.
ject to a supplementary pattern approval when they
influence, or are likely to influence, the results of
measurement or the regulatory conditions of use of
the instrument. 15.1.5.2 Tests for maximum errors
The body having approved the initial pattern shall 15.1.5.2.1 The errors of the meter shall be determined
decide to which extent the examinations and tests as for at least 6 flowrates (for example, at Qmax, 80 % Qmax,
described below shall be carried out on the modified 70 % Qmax, 50 % Qmax, 40 % Qmax and at Qmin),
pattern in relation with the nature of the modification. distributed over the measuring range at regular
intervals. At each flowrate the errors shall be
determined at least three times, independently. Each
15.1.4.3 When the body having approved the initial error shall not be greater than the maximum permis-
pattern judges that the modifications or additions are sible error (in absolute value), as specified in 6.2. The
not such as to influence the results of measurement, repeatability shall meet the requirements of 6.5.
13
OIML R 81: 1998 (E)
15.1.5.2.2 The following tests shall also be carried out: 15.1.7.2 Electronic conversion device
• test for maximum errors (15.1.5.2.1) at minimum Instead of the procedure in 15.1.7.1, it is also possible:
measured quantity, if practical;
• to verify separately the accuracy of associated
• tests with flow disturbances, if appropriate. measuring instruments (see 6.3.1, 6.3.2, and 6.3.3);
• to verify that the provisions of 15.1.6 are fulfilled;
15.1.5.3 Endurance test and
• to perform the examinations and tests described in
An endurance test should be carried out at the max-
15.1.10.
imum flowrate of the meter, with the liquid the meter
is intended to measure or with a liquid of similar
15.1.8 Pattern approval of an ancillary device
characteristics.
15.1.8.1 When an ancillary device that provides
When the meter is intended to measure different
primary indications is intended to be approved separ-
liquids, the test should be carried out with the liquid ately, its indications shall be compared with indica-
that provides the most severe conditions. tions provided by an indicating device already approved
An accuracy test shall precede the endurance tests. having the same scale interval or a smaller one.
For any measured quantity relating to the same
An endurance test shall be conducted according to measurement, the indications provided by the various
A.1.5. devices shall not deviate one from another.
After the endurance test, the meter is again subject to As far as possible, the necessary conditions for com-
a new accuracy test. patibility with other devices of a measuring system are
stated in the pattern approval certificate.
15.1.6 Pattern approval of an electronic calculator 15.1.8.2 Electronic devices may be approved separ-
ately when they are used for the transmission of
When an electronic calculator is submitted for a primary indications or other information necessary to
separate pattern approval, tests are conducted on the the determination of primary indications. For example,
calculator on its own, simulating different inputs with a device which concentrates information from two or
appropriate standards. For this purpose, the error more calculators and transmits to a single printing
obtained on the indication of the result is calculated device.
by considering that the true value is computed with
When at least one of the signals of the primary indica-
standard methods of calculation using the simulated
tion information is analogue, the device shall be tested
quantities applied to inputs of the calculator. associated with another device for which this Recom-
mendation provides maximum permissible errors.
15.1.7 Pattern approval of a conversion device When all the signals of the primary indication are
digital, the above provision may be applied. However,
When a conversion device is submitted for a separate when the inputs and outputs of the device are avail-
pattern approval, either of the procedures specified in able, it can be tested separately; in this case, only errors
15.1.7.1 or 15.1.7.2 may be used. due to the testing method are allowed and the device
shall present no other error.
15.1.7.1 General case In both cases and as far as possible, the necessary
conditions for compatibility with other devices of a
It is necessary to verify that the conversion device
measuring system are stated in the pattern approval
connected to all its associated measuring instruments certificate.
complies with the provisions of 6.3.6. For that
purpose, the volume to be converted is considered to
be without error when at metering conditions. In the 15.1.9 Pattern approval of a measuring system
case of an electronic conversion device, it is necessary
to perform the examination and tests described in The pattern approval of a measuring system consists
15.1.10. of verifying that the measuring system, the meter, and
14
OIML R 81: 1998 (E)
the constituent elements meet the corresponding a) Performance under the effect of influence factors
requirements, and that the constituent elements are When subjected to the effect of influence factors as
compatible with each other. provided for in the Annex, the equipment shall con-
tinue to operate correctly and the errors shall not
For the meter it is possible to verify that its own
exceed the applicable maximum permissible errors.
constituent elements meet the corresponding require-
ments and that they are compatible with each other. b) Performance under the effect of disturbances
The tests to carry out for the pattern approval of a When subjected to external disturbances as provided
measuring system may be determined on the basis of for in the Annex, the equipment shall either continue
the pattern approvals already granted for the con- to operate correctly or detect and indicate the
stituent elements of the system. presence of any significant fault. Significant faults
shall not occur on non-interruptible measuring
Note: Constituent elements may be subject to separate systems.
pattern approval when they are intended to be
part of several patterns of measuring systems. 15.1.10.3 Equipment under test (EUT)
This is advantageous when the various meas-
uring systems are manufactured by different Tests are carried out on the complete measuring
manufacturers and when the bodies responsible system where size and configuration permit, except
for the various pattern approvals are different. where there are other provisions in the Annex.
Otherwise, electronic devices shall be submitted sep-
arately to tests, in the form of equipment comprising
15.1.10 Pattern approval of an electronic device at least the following devices:
In addition to the examinations or tests which result • measuring transducer;
from the preceding paragraphs, an electronic meas- • calculator;
uring system or an electronic constituent element of
• indicating device;
this system shall be subject to the following tests and
examinations. • power supply device;
• correction device, if appropriate.
This equipment shall be included in a simulation set-
15.1.10.1 Design inspection up representative of the normal operation of the
measuring system. For example, the movement of the
This examination of documents aims at verifying that liquid may be simulated by an appropriate device.
the design of electronic devices and their checking The calculator shall be in its final housing.
facilities comply with the provisions of this Recom-
In all cases, peripheral equipment may be tested
mendation. It includes:
separately.
• an examination of the mode of construction and of
the electronic sub-systems and components used, to
verify their appropriateness for the intended use; 15.2 Initial verification
• considering faults likely to occur, to verify that in all 15.2.1 General
considered cases these devices comply with the
provisions of subclause 14.3; Initial verification of a measuring system:
• verification of the presence and effectiveness of the • is carried out in a single stage when the system can
test device(s) for the checking facilities. be transported without dismantling and when it is
verified under the intended conditions of use;
• is carried out in two stages in all other cases.
15.1.10.2 Performance tests
First stage: pertains to the flow sensor, on its own or
These tests aim at verifying that the measuring system fitted with its associated ancillary devices, or possibly
complies with the provisions of subclause 14.1.1 as included in a sub-system. The first stage tests may be
regards influence quantities. These tests are specified carried out on a test bench, possibly in the factory of
in Annex B. the manufacturer, or on the installed measuring
15
OIML R 81: 1998 (E)
system. At this stage, the metrological examinations 15.3 Subsequent verification

may be carried out with different liquids to those that
the system is intended to measure. 15.3.1 The procedures and requirements for sub-
sequent verification of a measuring system may be
The first stage also concerns the calculator and the identical to the initial verification.
density sensor notably. If necessary, the measurement
transducer and the calculator may be verified separ- 15.3.2 If the protective seals of the meter and/or the
ately. ancillary devices are intact, a complete examination of
the measuring system may not be necessary. To
determine the error curve, tests should be conducted
Second stage: pertains to the measuring system under at least with a volume of liquid equal to the minimum
actual working conditions. It is carried out at the place measured quantity, and at least at 60 % of the max-
of installation under operating conditions and with the imum flowrate of the meter.
intended liquid of use. However, the second stage may
be carried out in a place chosen by the body in charge 15.3.3 The maximum permissible errors on subsequent
of verification when the measuring system can be verification shall meet the requirements of 6.4.
transported without dismantling and when the tests
can be performed under the operating conditions
intended for the measuring system.
Initial verification of electronic systems shall include a
procedure to verify the presence and correct operation 16 Test conditions
of checking facilities by the use of test devices as
specified in subclause 14.3.
16.1 General
15.2.2 Tests Care shall be exercised to reduce vaporization and

volume changes to a minimum. When testing gravi-
15.2.2.1 When initial verification takes place in two metrically, the weigh tank and transfer systems shall
stages, the first stage shall include: be pre-cooled to the temperature of the liquid prior to
the start of the test to avoid the venting of vapor from
• an examination for conformity of the meter, includ- the vessel being weighed.
ing the associated ancillary devices (conformity with
the respective pattern);
16.1.1 Test liquid
• a metrological examination of the meter, including
the associated ancillary devices. The system shall be tested with the liquid to be meas-
The second stage shall include: ured, except that another cryogenic liquid may be used
if evidence can be provided indicating that the test
• an examination for conformity of the measuring liquid to be used will provide equivalent performance
system, including the meter and the ancillary and under the required test conditions.
additional devices;
• a metrological examination of the measuring 16.1.2 Test quantities
system; if possible, this examination is carried out
within the limits of operating conditions for the The minimum test quantity shall normally not be less
system. than 300 scale intervals of the meter under test and
1000 scale intervals of the master meter, whichever is
the smallest.
15.2.2.2 When initial verification takes place in one
stage, all the tests mentioned in subclause 15.2.2.1 However, the test quantity for determining the error
shall be performed. near the minimum measured quantity shall be equal
to the minimum measured quantity.
Note 1: For a flying start-stop test (that is, a test to
15.2.2.3 The maximum permissible errors on initial determine the time interval required to collect
verification shall meet the requirements of 6.4. a preselected weight of liquid), when the
16
OIML R 81: 1998 (E)
uncertainty in the standard can be maintained ate corrections shall be applied if product
as specified in clause 15, smaller test quant- conditions are abnormally affected by this test
ities may be used. However, in no case shall mode.
the test quantity be less than 140 kg for
devices having a maximum flowrate of at least
50 l/min, as specified by the manufacturer.
16.1.3 Temperature and pressure data
Note 2: When testing with a master meter, the test
quantity shall be equal to at least the amount The temperature and pressure of the measured liquid
delivered in 3 minutes at its maximum dis- shall be recorded during the test for the determination
charge rate. When testing uncompensated of density or volume correction factors, when ap-
meters in a continuous recycle flow, appropri- plicable.
17
OIML R 81: 1998 (E)
ANNEX A
TEST PROCEDURES
Performance tests - general
These tests should be applied uniformly by the legal A.1.3 Liquids

metrology services and are intended to ensure that the
The EUT should be tested with sufficient liquid or
instruments can perform and function as prescribed
liquids with similar characteristics over the range of
under rated conditions of use.
liquids for which the manufacturer has requested
When the effect of one influence quantity or disturb- approval (see 16.1.1 and 16.1.2).
ance is being evaluated, all other influence quantities
or disturbances are to be held relatively constant, at a
value close to normal. A.1.4 Flow rates for tests of maximum errors
The EUT shall be tested according to the requirements
Relatively stable test conditions for each of the para-
given in 15.1.5.2.
meters of the liquid are as follows:
temperature: ± 5 °C;
A.1.5 Endurance
pressure: ± 20 % not to exceed 200 kPa (2 bar);
flowrate: ± 5 %. An endurance test shall be conducted as follows
(see 15.1.5.3):
The instrument should be tested with the liquid to be • an accuracy test shall be conducted prior to the
commercially measured or with a liquid of the same endurance test;
general physical characteristics (see 16.1.1).
• as far as possible, the meter is subjected to an
endurance test on a test bench. However it is
A.1 Pattern approval tests accepted that the meter be temporarily mounted in
a measuring system in normal operation. It is then
The gravimetric test method is recommended; other necessary that the nominal operating flowrate of the
suitable methods may be used provided the require- measuring system be more than 0.8 Qmax;
ments of A.1.1 are met. • The endurance test shall be conducted for 100 hours
in one or several periods at a flowrate from
A.1.1 Uncertainty 80 % Qmax to Qmax;
• After the 100 hour test, an accuracy test shall be
The expanded uncertainty, U (for coverage factor k = 2), conducted with the same quantity as above. The test
for the reference standard (including its indicating results shall not vary from the first test by more
device), shall be less than 1/5 of the applicable
than 1.5 % of the measured quantity, without any
maximum permissible errors of the measuring system
adjustment or correction.
under test for pattern approval. (See Guide to the
Expression of Uncertainty in Measurement, 1995).
A.2 Initial and subsequent verification
A.1.2 Quantities
tests
Any test quantity shall be equal to or greater than the
minimum measured quantity (see 16.1.2). The verification of the measuring system may be con-
ducted by the gravimetric or volumetric method, or
A.1.2.1 Repeatability tests conducted to determine with a master meter.
compliance with 6.5
A.2.1 Uncertainty
Repeatability tests shall be conducted with quantities
equal to or greater than five times the minimum meas- The expanded uncertainty, U (for coverage factor k = 2),
ured quantity. for the reference standard (including its indicating
18
OIML R 81: 1998 (E)
device), shall be less than 1/3 of the applicable max- A.2.3 Flow rates for tests of maximum errors
imum permissible errors of the measuring system under
test for initial and subsequent verifications. (See Guide The EUT shall be tested at the maximum flowrate
to the Expression of Uncertainty in Measurement, 1995). achievable under the conditions of installation, the
minimum flowrate marked on the instrument, and at
least one intermediate flowrate. At least one test shall
A.2.2 Quantities be conducted at each flowrate (see 15.1.5.2.1).
Any test quantity shall be equal to or greater than the Note: For subsequent verification, see subclause
minimum measured quantity (see 16.1.2). 15.3.2.
19
OIML R 81: 1998 (E)
ANNEX B
TEST PROCEDURES
Performance tests - Applicable to electronic equipment
B.1 General approval is granted, the data plate shall indicate the
corresponding limits of use. Conditions of use for
This Annex specifies the tests intended to ensure that which the instrument is approved shall be provided by
electronic measuring systems perform and function as the manufacturers. The metrology service shall verify
prescribed in a specified environment and under spe- that the conditions of use are met.
cified conditions. Where appropriate, each test in-
dicates the reference conditions under which the
intrinsic error is determined.
These tests supplement those in Annex A. B.3 Reference conditions
When the effect of one influence quantity is being Ambient temperature: 15 °C to 25 °C;
evaluated, all other influence quantities are to be held Relative humidity: 45 % to 75 %;
relatively constant, at values close to reference condi- Atmospheric pressure: 86 kPa to 106 kPa;
tions. Power voltage: Nominal voltage;
When the effect of a disturbance is being evaluated, no Power frequency: Nominal frequency.
other disturbance shall be present and all influence
During each test, the temperature and relative humid-
quantities shall be held relatively constant, at values
ity shall not vary by more than 5 °C or 10 % respect-
close to reference conditions.
ively, within the reference range.
B.2 Severity levels (see OIML D 11)

B.4 Performance tests
For each performance test, typical test conditions are (refer to the summary table)
indicated that correspond to the climatic and mech-
anical environment conditions to which measuring
systems are usually exposed. Notes: Simulated tests
Measuring systems are divided into three classes Except for B.4.3 and B.4.4 (non-operational tests), the
according to the climatic and mechanical environment tests may be conducted by simulating the flow without
conditions: any actual product passing through the measuring
system, if it can be shown that the flow sensor is not
• class B for a fixed instrument installed in a building; affected by the test conditions.
• class C for a fixed instrument installed outdoors;
Note 1 Simulated flow must produce an output or
• class I for a mobile instrument, especially those
outputs from the measuring system corres-
mounted on a truck.
ponding to an actual flowrate between the
minimum and maximum flowrates for the
The applicant for pattern approval may define specific system.
environmental conditions for the future use of the
equipment in the documentation supplied to the Note 2 While flow is being simulated, it must be
metrology service. In this case, the metrology service possible to ascertain that the flow measure-
carries out the tests at severity levels corresponding to ment capabilities of the system are fully opera-
these specific environmental conditions. If pattern tional.
20
OIML R 81: 1998 (E)
Summary of performance tests
Severity level
Test Nature of the (reference OIML D 11)
influence quantity
B C I
B.4.1 Dry heat Influence factor 2 3 3
B.4.2 Cold Influence factor 2 3 3
B.4.3 Damp heat, cyclic Influence factor 1 2 2
B.4.4 Vibration Influence factor - - 3

(sinusoidal)
B.4.5.1 AC power supply Influence factor 1 1 1
voltage variations
B.4.5.2 DC power supply Disturbance 1 1 1
voltage variations
B.4.6 Short time
power reductions Disturbance 1a & 1b 1a & 1b 1a & 1b
B.4.7 Bursts Disturbance 2 2 2
B.4.8 Electrostatic Disturbance 1 1 1

discharge
B.4.9 Electromagnetic Disturbance 2 2 2
susceptibility
B.4.10 Perturbations on Disturbance 2 2 2
DC voltage powered
instruments
B.4.1 Dry heat Background information concerning dry heat tests is

given in IEC Publication 60068-3-1, first edition, 1974
Test method and first supplement 60068-3-1A, 1978, Part 3:
Background information, section one: Cold and dry
Dry heat (non condensing). heat test. General background information on basic
environmental testing procedures is given in IEC
Object of the test Publication 60068-1, 1988.
To verify compliance with the provisions in subclause
14.1.1 under conditions of high temperature. Test procedure in brief
References
The test consists of exposing the EUT to a temperature
IEC Publication 60068-2-2, fourth edition, 1974, Basic of 55 °C (class C or I) or 40 °C (class B) under “free
environmental testing procedures, Part 2: Tests, Test air” conditions for a 2 hour period after the EUT has
Bd: Dry heat, for heat dissipating equipment under reached temperature stability. The EUT shall be tested
test (EUT) with gradual change temperature. for at least one flowrate (or simulated flowrate):
21
OIML R 81: 1998 (E)
• at the reference temperature of 20 °C following air” conditions for a 2 hour period after the EUT has
conditioning; reached temperature stability. The EUT shall be tested
• at the temperature of 55 °C (class C or I) or 40 °C for at least one flowrate (or simulated flowrate):
(class B), 2 hours following temperature stabilization;
• at the reference temperature of 20 °C following con-
• after recovery of the EUT at the reference temper-
ditioning;
ature of 20 °C.
• at a temperature of –25 °C or –10 °C, 2 hours follow-
Test severity ing temperature stabilization;
• after recovery of the EUT at the reference temper-
1) Temperature: severity level 2: 40 °C ature of 20 °C.
severity level 3: 55 °C
2) Duration: 2 hours. Test severity
1) Temperature: severity level 2: –10 °C;
Number of test cycles severity level 3: –25 °C.
One cycle. 2) Duration: 2 hours.
Maximum allowable variations
Number of test cycles
All functions shall operate as designed.
One cycle.
All indications shall be within the maximum permiss-
ible errors.
B.4.2 Cold All indications shall be within the maximum permiss-
ible errors.
Test method
Cold.
Object of the test B.4.3 Damp heat, cyclic
14.1.1 under conditions of low temperature. Test method
References Damp heat, cyclic (condensing).
IEC Publication 60068-2-1, 1990, Basic environmental Object of the test

testing procedures, Part 2: Tests, Test A: Cold,
Section 3 - Test Ad: Cold for heat dissipating EUT with To verify compliance of the electronic measuring ins-
gradual change of temperature. trument with the provisions in subclause 14.1.1 under
conditions of high humidity when combined with
Background information concerning cold tests is given cyclic temperature changes.
in IEC Publication 60068-3-1, first edition 1974 and
first supplement 60068-3-1A, 1978 Part 3: Background
References
information, section one: Cold and dry heat tests.
General background information on basic environ- IEC Publication 60068-2-30, second edition, 1980,
mental testing procedures is given in IEC Publication Basic environmental testing procedures, Part 2: Tests,
60068-1, 1988. test Db: Damp heat, cyclic (12 h + 12 h cycle), test
variant 2.
Test procedure in brief
Background information concerning damp heat tests
The test consists of exposing the EUT to a temperature is given in IEC Publication 60068-2-28, third edition,
of –25 °C (class C or I) or –10 °C (class B) under “free 1990: Guidance for damp heat tests.
22
OIML R 81: 1998 (E)
Test procedure in brief Test procedure in brief
The test consists of exposing the non-operational EUT The non-operational EUT shall be tested by sweeping
(power supplied and on) to cyclic temperature varia- the frequency in the specified frequency range, at 1
tions between 25 °C and the upper temperature of octave/minute, at the specified acceleration level with
55 °C (class C or I) or 40 °C (class B), maintaining the a specified number of sweep cycles per axis. The EUT
relative humidity above 95 % during the temperature shall be tested in its three, mutually perpendicular
changes and during the phases at low temperature, main axes, mounted on a rigid fixture by its normal
and at 93 % at the upper temperature phases. Conden- mounting means. It shall normally be mounted so that
sation should occur on the EUT during the temper- the gravitational force acts in the same direction as it
ature rise. The standard atmospheric stabilizing period would in normal use. After the vibration test, a per-
before and recovery after the cyclic exposure are formance test under reference conditions for at least
indicated in IEC Publication 60068-2-30. After one flowrate is conducted.
recovery, a performance test under reference conditions
for at least one flowrate (or simulated flowrate) is Test severity
conducted.
1) Frequency range: 10 Hz–150 Hz.
Test severity 2) Max. acceleration level: 20 m⋅s2.
1) Upper temperature: severity level 1: 40 °C; Number of test cycles

severity level 2: 55 °C.
20 sweep cycles per axis.
2) Humidity: > 93 %.
3) Duration: 24 hours.
Number of test cycles All functions shall operate as designed.
Two cycles. All indications shall be within the maximum permiss-
ible errors.
ible errors. B.4.5 Power voltage variation
B.4.5.1 AC power supply

B.4.4 Vibration
Test method
Test method Variation in AC mains power supply (single phase).
Sinusoidal vibration.
Object of the test
Object of the test To verify compliance with the provisions in subclause

14.1.1 under conditions of varying AC mains power
To verify compliance of the electronic measuring supply.
instrument to the provisions in subclause 14.1.1 under
conditions of sinusoidal vibration.
Test procedure in brief
References The test consists of exposing the EUT to power voltage

variations, while the EUT is operating under normal
IEC Publication 60068-2-6, 1995, Basic environmental atmospheric conditions. The EUT shall be tested for at
testing procedures, Part 2: Tests. Test Fc: Vibration least one flowrate (or simulated flowrate), at the upper
(sinusoidal). and lower voltage limits.
23
OIML R 81: 1998 (E)
Test severity B.4.6 Short time power reduction (not applicable

to systems with a DC power supply)
Mains voltage: upper limit: Unom + 10 %;
lower limit: Unom – 15 %.
Test method
Number of test cycles Short time interruptions and reductions of mains

voltage.
One cycle.
Object of the test
Maximum allowable variations To verify compliance with the provisions in subclause

14.1.1 under conditions of short time mains voltage
All functions shall operate as designed. interruptions and reductions.
ible errors. References
IEC Publication 61000-4-11 (1994), Electromagnetic
compatibility (EMC) Part 4: Testing and measurement
techniques - Section 11. Voltage dips, short inter-
ruptions and voltage variations immunity tests.
B.4.5.2 DC power supply Section 5.2 (Test levels - Voltage variation). Section
8.2.2 (Execution of the test-voltage variation).
Test method Test procedure in brief

Variation in DC power supply. The test consists of subjecting the EUT to voltage
interruptions from nominal voltage to zero voltage for
Object of the test a duration equal to 10 ms, and from nominal voltage
to 50 % of nominal for a duration equal to 20 ms. The
To verify compliance with the provisions subclause mains voltage interruptions and reductions shall be
14.1.1 under conditions of varying DC power supply. repeated ten times with a time interval of at least 10
seconds. The EUT shall be tested for at least one flow-
Test procedure in brief rate (or simulated flowrate).
The test consists of exposing the EUT to power voltage Test severity
variations, while the EUT is operating under normal
atmospheric conditions. The EUT shall be tested at 100 % voltage interruption for a period equal to 10 ms;
least one flowrate (or simulated flowrate), at the upper 50 % voltage reduction for a period equal to 20 ms.
and lower voltage limits
Number of test cycles
Test severity Ten tests with a minimum of 10 seconds between tests.
DC voltage: upper limit: Unom + 10 %; Maximum allowable variations
lower limit: Unom – 15 %.
a) For interruptible measuring systems, either the
difference between the quantity indication during
Number of test cycles the test and the indication under reference con-
One cycle. ditions shall not exceed the values given in 3.24 or
the measuring system shall detect and act upon a
significant fault, in compliance with subclause
Maximum allowable variations 14.1.1.
b) For non-interruptible measuring systems, the
All indications shall be within the maximum permiss- the test and the indication under reference con-
ible errors. ditions shall not exceed the values given in 3.24.
24
OIML R 81: 1998 (E)
B.4.7 Bursts (not applicable to systems with a DC B.4.8 Electrostatic discharge

power supply)
Test method
Electrostatic discharge (ESD).
Test method
Electrical bursts. Object of the test
Object of the test 14.1.1 under conditions of electrostatic discharges.
To verify compliance with the provisions in subclause References
14.1.1 under conditions where electrical bursts are
superimposed on the mains voltage. IEC Publication 61000-4-2 (1995) Electromagnetic
References techniques - Section 2: Electrostatic discharge
immunity test. Basic EMC Publication.
IEC Publication 61000-4-4 (1995), Electromagnetic
compatibility (EMC) Part 4: Testing and measurement Test procedure in brief
techniques - Section 4: Electrical fast transient/burst
A capacitor of 150 pF is charged by a suitable DC
immunity test. Basic EMC publication.
voltage source. The capacitor is then discharged
through the EUT by connecting one terminal to
Test procedure in brief ground (chassis) and the other via 150 ohms to
surfaces which are normally accessible to the operator.
The test consists of subjecting the EUT to bursts of
double exponential wave-form transient voltages. Each In the case of contact discharges, the tip of the dis-
spike shall have a rise time of 5 ns and a half amp- charge electrode shall touch the EUT before the
litude duration of 50 ns. The burst length shall be discharge switch is operated.
15 ms, the burst period (repetition time interval) shall In the case of painted surfaces covering a conducting
be 300 ms. All these bursts shall be applied during the substrate, the following procedure shall be adopted:
same measurement or simulated measurement.
If the coating is not declared to be an insulating
Test severity coating by the instrument manufacturer, then the
point tip of the generator shall penetrate the coating
Amplitude (peak value) 1000 V. so as to make contact with the conducting substrate.
Coating declared as insulating by the manufacturer
Number of test cycles shall only be submitted to the air discharge. The
contact discharge test shall not be applied to such
At least 10 positive and 10 negative randomly phased surfaces.
bursts shall be applied at 1000 V.
In the case of air discharges, the round discharge tip
Maximum allowable variations of the discharge electrode shall be approached as fast
as possible (without causing mechanical damage) to
a) For interruptible measuring systems, either the touch the EUT. After each discharge, the ESD gen-
difference between the quantity indication during erator (discharge electrode) shall be removed from the
the test and the indication under reference con- EUT. The generator is then retriggered for a new single
ditions shall not exceed the values given in 3.24 or discharge. This procedure shall be repeated until the
the measuring system shall detect and act upon a discharges are completed. In the case of an air dis-
significant fault, in compliance with subclause charge test, the discharge switch which is used for
14.1.1. contact discharge, shall be closed.
b) For non-interruptible measuring systems, the Test severity

the test and the indication under reference con- Air discharge: up to and including 8 kV;
ditions shall not exceed the values given in 3.24. Contact discharge: up to and including 6 kV.
25
OIML R 81: 1998 (E)
Number of test cycles If antennae with circular polarization, i.e. log-spiral or

At least ten discharges shall be applied at intervals of helical antennae are used to generate the electromag-
at least 10 seconds between discharges, during the netic field, a change in the position of the antennae is
same measurement or simulated measurement. not necessary.
When the test is carried out in a shielded enclosure, to
comply with international law prohibiting interference
a) For interruptible measuring systems, either the to radio communications, anechoic shielding may be
difference between the quantity indication during necessary to reduce reflection from the walls.
the test and the indication under reference con-
ditions shall not exceed the values given in 3.24 or Test severity
significant fault, in compliance with subclause Frequency range 26 MHz–1000 MHz
14.1.1. Field strength 3 V/m
Modulation 80 %, 1 kHz sine wave
differences between the quantity indication during Maximum allowable variations
the test and the indication under reference con-
ditions shall not exceed the values given in 3.24. a) For interruptible measuring systems, either the
B.4.9 Electromagnetic susceptibility the test and the indication under reference con-
ditions shall not exceed the values given in 3.24 or
Test method significant fault, in compliance with subclause
Electromagnetic fields (radiated). 14.1.1.
Object of the test difference between the quantity indication during
To verify compliance with the provisions in subclause the test and the indication under reference con-
14.1.1 under various electromagnetic fields. ditions shall not exceed the values given in 3.24.
References
B.4.10 Perturbations on DC voltage powered
IEC Publication 61000-4-3 (1995) Electromagnetic instruments
techniques - Section 3: Radiated, radio-frequency, Electronic measuring systems with DC voltage power
electromagnetic field immunity test. supply shall not be subjected to the tests B.4.5.1 AC
power supply, B.4.6 Short time power reduction, and
Test procedure in brief B.4.7 Bursts. They shall meet the following:
The EUT shall be exposed to an electromagnetic field
strength as specified by the severity level during the 1 General
measurement or simulated measurement. The field When the power supplied is less than –15 % Unom, or
strength can be generated in the following ways: greater than +10 % Unom, during a measurement the
EUT shall either indicate within mpe or not provide an
• the strip line is used at frequencies below 30 MHz indication that could be construed as measurement
(in some cases 150 MHz) for smaller EUT’s; value.
• the long wire is used at frequencies below 30 MHz
for larger EUT’s; 2 For instruments powered by the battery of a vehicle
• dipole antennae or antennae with circular polariza- Test pulses 1, 2, and 3 as specified in ISO 7637: Road
tion placed 1 m from the EUT are used at high
vehicles. Electrical disturbance by conduction and
frequencies.
coupling, Part 1 or Part 2 as appropriate shall be
The specified field strength is established prior to effected. The pulses are to be repeated for as long as
testing (without the EUT in the field). necessary to complete the test.
The field is generated in two orthogonal polarizations The pattern approval certificate shall indicate at least
and the frequency range is scanned slowly. Severity Level II.
26
OIML R 81: 1998 (E)
ANNEX C
TABLES OF DENSITY FOR
LIQUID ARGON, HELIUM, HYDROGEN, NITROGEN AND OXYGEN
The tables on the following pages give the values in SI Table 3 – Hydrogen
units of the density as a function of temperature and Temperature from 19.4 K to 32.8 K and pressure
pressure for liquid argon, helium, hydrogen, nitrogen up to 1.2 MPa;
and oxygen. Two tables are given for each fluid:
Table 4 – Nitrogen
• the “-a” tables give the values of vapor pressure,
density and volume per mass unit as a function of Temperature from 75 K to 126 K and pressure
temperature for the so-called saturated liquid (liquid up to 3 MPa;
under its vapor pressure);
Table 5 – Oxygen
• the “-b” tables give the values of density as a Temperature from 88 K to 154 K and pressure
function of temperature for the so-called subcooled up to 4 MPa.
liquid (liquid under pressure).
The tables were drawn up from the computer programs
which were used to prepare similar tables for the
Ranges of the tables:
United States Compressed Gas Association and which
are reported in [1]. The data provided with these tables
Table 1 – Argon
were prepared by the Thermophysics Division of the
Temperature from 85 K to 150 K and pressure National Institute of Standards and Technology
up to 4 MPa; (former National Bureau of Standards) and are
consistent with the data reported in [1] and in the
Table 2 – Helium source documents [2] and [3]. The computer programs
Temperature from 4 K to 5.14 K and pressure which were used to prepare these tables are available
up to 0.22 MPa; from the NIST Office of Standard Reference Data [4].
References applicable to Annex C
[1] Younglove, B.A., Tables of Industrial Gas Container [4] For magnetic tape, order NIST Standard Reference Data
Contents and Density for Oxygen, Argon, Nitrogen, Base 5 for helium properties and Data Base 6 for the
Helium and Hydrogen. Nat. Bur. Stand. (USA) Tech. other fluids from the Office of Standard Reference Data,
Note No. 1079, June 1985. 195 p. A320 Physics Building, National Institute of Standards
and Technology, Gaithersburg, MD 20899, USA.
[2] McCarty, R.D., Interactive Fortran IV Computer
Programs for the Thermodynamic and Transport
Properties of Selected Cryogens (Fluids Pack). Nat. Bur.
Stand. (USA) Tech. Note No. 1025, October 1980. 112 p. Note: The National Institute of Standards and Technology (NIST)
has prepared these tables at the request of the Organisation
[3] Younglove, B.A., Thermophysical Properties of Fluids. I. Internationale de Métrologie Légale (OIML). Since they
Argon, Ethylene, Parahydrogen, Nitrogen, Trifluoride were prepared under the auspices of the United States
and Oxygen. J. Phys. Chem. Ref. Data 11, No. 4, 1982. Government, they are not subject to copyright.
27
TABLE 1–a
ARGON
Temp. Vapor pressure Density Volume / mass unit

K MPa kg/m3 dm3/kg
85.0 .0790 1407.0 .7107

86.0 .0883 1401.0 .7138
87.0 .0983 1394.9 .7169
88.0 .1093 1388.8 .7200
89.0 .1211 1382.6 .7233
90.0 .1339 1376.4 .7265
91.0 .1477 1370.1 .7299
92.0 .1626 1363.8 .7332
93.0 .1785 1357.4 .7367
94.0 .1956 1351.0 .7402
95.0 .2139 1344.5 .7438
96.0 .2335 1337.9 .7474
97.0 .2543 1331.3 .7511
98.0 .2765 1324.7 .7549
99.0 .3001 1318.0 .7588
100.0 .3252 1311.2 .7627
101.0 .3518 1304.3 .7667
102.0 .3799 1297.4 .7708
103.0 .4097 1290.4 .7749
104.0 .4411 1283.4 .7792
105.0 .4743 1276.3 .7835
106.0 .5092 1269.1 .7880
107.0 .5459 1261.9 .7925
108.0 .5846 1254.5 .7971
109.0 .6252 1247.1 .8019
110.0 .6678 1239.6 .8067
111.0 .7124 1232.0 .8117
112.0 .7591 1224.4 .8167
113.0 .8080 1216.6 .8219
114.0 .8592 1208.8 .8273
115.0 .9126 1200.8 .8328
116.0 .9683 1192.8 .8384
117.0 1.0264 1184.6 .8441
118.0 1.0870 1176.4 .8501
119.0 1.1501 1168.0 .8562
120.0 1.2158 1159.4 .8625
121.0 1.2841 1150.8 .8690
122.0 1.3550 1142.0 .8757
123.0 1.4288 1133.0 .8826
124.0 1.5053 1123.9 .8897
28 OIML R 81: 1998 (E)

TABLE 1–a (cont’d)
ARGON

K MPa kg/m3 dm3/kg
125.0 1.5848 1114.6 .8971

126.0 1.6671 1105.2 .9048
127.0 1.7525 1095.5 .9128
128.0 1.8410 1085.6 .9211
129.0 1.9326 1075.5 .9298
130.0 2.0274 1065.2 .9388
131.0 2.1256 1054.6 .9483
132.0 2.2271 1043.7 .9582
133.0 2.3320 1032.4 .9686
134.0 2.4405 1020.8 .9796
135.0 2.5526 1008.9 .9912
136.0 2.6684 996.5 1.0035
137.0 2.7880 983.6 1.0167
138.0 2.9114 970.2 1.0307
139.0 3.0389 956.1 1.0459
140.0 3.1704 941.4 1.0622
141.0 3.3061 925.9 1.0801
142.0 3.4462 909.4 1.0996
143.0 3.5908 891.8 1.1213
144.0 3.7399 872.9 1.1456
145.0 3.8938 852.3 1.1733
146.0 4.0527 829.6 1.2054
147.0 4.2168 804.0 1.2437
148.0 4.3863 774.3 1.2915
149.0 4.5617 737.7 1.3557
150.0 4.7434 687.3 1.4550
OIML R 81: 1998 (E) 29

TABLE 1–b ARGON (Temperature: K Pressure: MPa Density: kg/m3)
PRES .08 .10 .20 .40 .60 .80 1.00 1.50 2.00 2.50 3.00 3.50 4.00
TEMP
85.0 1407.8 1407.9 1408.2 1408.7 1409.3 1409.9 1410.5 1411.9 1413.3 1414.7 1416.1 1417.4 1418.8
85.5 1404.9 1405.1 1405.7 1406.3 1406.9 1407.5 1408.9 1410.3 1411.7 1413.1 1414.5 1415.9
86.0 1401.8 1402.1 1402.7 1403.3 1403.9 1404.4 1405.9 1407.3 1408.8 1410.2 1411.6 1413.0
86.5 1398.8 1399.1 1399.7 1400.2 1400.8 1401.4 1402.9 1404.3 1405.8 1407.2 1408.6 1410.0
87.0 1395.7 1396.0 1396.6 1397.2 1397.8 1398.4 1399.9 1401.3 1402.8 1404.2 1405.7 1407.1
87.5 1392.9 1393.5 1394.1 1394.7 1395.3 1396.8 1398.3 1399.8 1401.2 1402.7 1404.1
88.0 1389.8 1390.4 1391.1 1391.7 1392.3 1393.8 1395.3 1396.8 1398.3 1399.7 1401.2
88.5 1386.7 1387.4 1388.0 1388.6 1389.2 1390.7 1392.2 1393.8 1395.2 1396.7 1398.2
89.0 1383.6 1384.2 1384.9 1385.5 1386.1 1387.7 1389.2 1390.7 1392.2 1393.7 1395.2
89.5 1380.5 1381.1 1381.8 1382.4 1383.0 1384.6 1386.1 1387.7 1389.2 1390.7 1392.2
90.0 1377.3 1378.0 1378.6 1379.3 1379.9 1381.5 1383.1 1384.6 1386.1 1387.7 1389.2
90.5 1374.2 1374.8 1375.5 1376.1 1376.8 1378.4 1380.0 1381.5 1383.1 1384.6 1386.2
91.0 1371.0 1371.7 1372.3 1373.0 1373.6 1375.3 1376.9 1378.4 1380.0 1381.6 1383.1
91.5 1367.8 1368.5 1369.2 1369.8 1370.5 1372.1 1373.7 1375.3 1376.9 1378.5 1380.1
92.0 1364.6 1365.3 1366.0 1366.6 1367.3 1369.0 1370.6 1372.2 1373.8 1375.4 1377.0
92.5 1361.4 1362.1 1362.8 1363.5 1364.1 1365.8 1367.5 1369.1 1370.7 1372.4 1374.0
93.0 1358.2 1358.9 1359.6 1360.2 1360.9 1362.6 1364.3 1366.0 1367.6 1369.3 1370.9
93.5 1354.9 1355.6 1356.3 1357.0 1357.7 1359.4 1361.1 1362.8 1364.5 1366.2 1367.8
94.0 1351.7 1352.4 1353.1 1353.8 1354.5 1356.2 1358.0 1359.7 1361.4 1363.0 1364.7
94.5 1349.1 1349.8 1350.6 1351.3 1353.0 1354.8 1356.5 1358.2 1359.9 1361.6
95.0 1345.8 1346.6 1347.3 1348.0 1349.8 1351.6 1353.3 1355.0 1356.8 1358.4
95.5 1342.5 1343.3 1344.0 1344.7 1346.5 1348.3 1350.1 1351.9 1353.6 1355.3
96.0 1339.2 1340.0 1340.7 1341.5 1343.3 1345.1 1346.9 1348.7 1350.4 1352.2
96.5 1335.9 1336.7 1337.4 1338.2 1340.0 1341.8 1343.7 1345.5 1347.2 1349.0
97.0 1332.6 1333.3 1334.1 1334.8 1336.7 1338.6 1340.4 1342.2 1344.0 1345.8
97.5 1329.2 1330.0 1330.8 1331.5 1333.4 1335.3 1337.2 1339.0 1340.8 1342.6
98.0 1325.8 1326.6 1327.4 1328.2 1330.1 1332.0 1333.9 1335.8 1337.6 1339.4
98.5 1322.4 1323.2 1324.0 1324.8 1326.8 1328.7 1330.6 1332.5 1334.4 1336.2
99.0 1319.0 1319.8 1320.6 1321.4 1323.4 1325.4 1327.3 1329.2 1331.1 1333.0
99.5 1315.6 1316.4 1317.2 1318.0 1320.1 1322.0 1324.0 1325.9 1327.9 1329.8
100.0 1312.2 1313.0 1313.8 1314.6 1316.7 1318.7 1320.7 1322.6 1324.6 1326.5
100.5 1308.7 1309.5 1310.4 1311.2 1313.3 1315.3 1317.3 1319.3 1321.3 1323.2
101.0 1305.2 1306.1 1306.9 1307.8 1309.9 1311.9 1314.0 1316.0 1318.0 1320.0
101.5 1301.7 1302.6 1303.4 1304.3 1306.4 1308.5 1310.6 1312.6 1314.7 1316.7
102.0 1298.2 1299.1 1299.9 1300.8 1303.0 1305.1 1307.2 1309.3 1311.3 1313.4
102.5 1294.7 1295.5 1296.4 1297.3 1299.5 1301.7 1303.8 1305.9 1308.0 1310.0
103.0 1292.0 1292.9 1293.8 1296.0 1298.2 1300.4 1302.5 1304.6 1306.7
103.5 1288.4 1289.4 1290.3 1292.5 1294.7 1296.9 1299.1 1301.2 1303.3
104.0 1284.9 1285.8 1286.7 1289.0 1291.3 1293.5 1295.7 1297.8 1300.0
104.5 1281.2 1282.2 1283.1 1285.5 1287.7 1290.0 1292.2 1294.4 1296.6
105.0 1277.6 1278.6 1279.5 1281.9 1284.2 1286.5 1288.8 1291.0 1293.2
105.5 1274.0 1274.9 1275.9 1278.3 1280.7 1283.0 1285.3 1287.5 1289.8
106.0 1270.3 1271.3 1272.3 1274.7 1277.1 1279.5 1281.8 1284.1 1286.3
106.5 1266.6 1267.6 1268.6 1271.1 1273.5 1275.9 1278.3 1280.6 1282.9
107.0 1262.9 1263.9 1264.9 1267.4 1269.9 1272.4 1274.8 1277.1 1279.4
107.5 1259.2 1260.2 1261.2 1263.8 1266.3 1268.8 1271.2 1273.6 1276.0
108.0 1255.4 1256.4 1257.5 1260.1 1262.6 1265.2 1267.6 1270.1 1272.5
108.5 1252.7 1253.7 1256.4 1259.0 1261.5 1264.0 1266.5 1268.9
109.0 1248.9 1250.0 1252.6 1255.3 1257.9 1260.4 1262.9 1265.4
109.5 1245.0 1246.2 1248.9 1251.6 1254.2 1256.8 1259.3 1261.9
110.0 1241.2 1242.3 1245.1 1247.8 1250.5 1253.1 1255.7 1258.3
110.5 1237.3 1238.5 1241.3 1244.1 1246.8 1249.5 1252.1 1254.7
111.0 1233.4 1234.6 1237.5 1240.3 1243.1 1245.8 1248.4 1251.1
111.5 1229.5 1230.7 1233.6 1236.5 1239.3 1242.1 1244.8 1247.4
112.0 1225.5 1226.7 1229.7 1232.6 1235.5 1238.3 1241.1 1243.8
112.5 1221.5 1222.7 1225.8 1228.8 1231.7 1234.5 1237.4 1240.1
113.0 1218.7 1221.8 1224.9 1227.8 1230.8 1233.6 1236.4
113.5 1214.7 1217.9 1220.9 1224.0 1226.9 1229.8 1232.7
114.0 1210.6 1213.8 1217.0 1220.1 1223.1 1226.1 1228.9
114.5 1206.5 1209.8 1213.0 1216.2 1219.2 1222.2 1225.2
115.0 1202.4 1205.7 1209.0 1212.2 1215.3 1218.4 1221.4
115.5 1198.2 1201.6 1204.9 1208.2 1211.4 1214.5 1217.6
30 OIML R 81: 1998 (E)

TABLE 1–b (cont’d) ARGON (Temperature: K Pressure: MPa Density: kg/m3)
PRES .08 .10 .20 .40 .60 .80 1.00 1.50 2.00 2.50 3.00 3.50 4.00
TEMP
116.0 1194.0 1197.5 1200.9 1204.2 1207.4 1210.6 1213.7
116.5 1189.7 1193.3 1196.8 1200.1 1203.5 1206.7 1209.9
117.0 1189.1 1192.6 1196.1 1199.4 1202.7 1206.0
117.5 1184.8 1188.4 1191.9 1195.4 1198.8 1202.0
118.0 1180.5 1184.2 1187.8 1191.3 1194.7 1198.1
118.5 1176.1 1179.9 1183.6 1187.2 1190.7 1194.1
119.0 1171.7 1175.6 1179.4 1183.0 1186.6 1190.1
119.5 1167.3 1171.3 1175.1 1178.8 1182.5 1186.0
120.0 1162.8 1166.9 1170.8 1174.6 1178.3 1182.0
120.5 1158.3 1162.4 1166.4 1170.4 1174.1 1177.8
121.0 1153.7 1157.9 1162.1 1166.0 1169.9 1173.7
121.5 1149.0 1153.4 1157.6 1161.7 1165.7 1169.5
122.0 1144.3 1148.8 1153.1 1157.3 1161.4 1165.3
122.5 1139.6 1144.2 1148.6 1152.9 1157.0 1161.0
123.0 1134.7 1139.5 1144.0 1148.4 1152.6 1156.7
123.5 1129.9 1134.7 1139.3 1143.8 1148.2 1152.4
124.0 1129.9 1134.6 1139.2 1143.7 1148.0
124.5 1125.0 1129.9 1134.6 1139.2 1143.6
125.0 1120.0 1125.1 1129.9 1134.6 1139.1
125.5 1115.0 1120.2 1125.2 1129.9 1134.5
126.0 1109.9 1115.2 1120.3 1125.2 1130.0
126.5 1104.7 1110.2 1115.5 1120.5 1125.3
127.0 1099.4 1105.1 1110.5 1115.7 1120.7
127.5 1094.1 1099.9 1105.5 1110.8 1115.9
128.0 1088.6 1094.7 1100.4 1105.9 1111.1
128.5 1083.1 1089.3 1095.2 1100.9 1106.3
129.0 1077.4 1083.9 1090.0 1095.8 1101.3
129.5 1071.7 1078.4 1084.7 1090.7 1096.4
130.0 1072.7 1079.2 1085.4 1091.3
130.5 1067.0 1073.7 1080.1 1086.2
131.0 1061.1 1068.1 1074.7 1081.0
131.5 1055.1 1062.4 1069.2 1075.7
132.0 1049.0 1056.6 1063.6 1070.3
132.5 1042.7 1050.6 1057.9 1064.8
133.0 1036.3 1044.5 1052.1 1059.3
133.5 1029.7 1038.3 1046.2 1053.6
134.0 1023.0 1031.9 1040.2 1047.8
134.5 1016.0 1025.4 1034.0 1041.9
135.0 1018.7 1027.7 1035.9
135.5 1011.8 1021.2 1029.8
136.0 1004.7 1014.5 1023.5
136.5 997.4 1007.7 1017.1
137.0 989.8 1000.7 1010.6
137.5 981.9 993.5 1003.8
138.0 973.8 986.0 996.9
138.5 965.3 978.3 989.8
139.0 970.3 982.5
139.5 962.0 974.9
140.0 953.3 967.0
140.5 944.2 958.9
141.0 934.6 950.5
141.5 924.5 941.6
142.0 913.7 932.4
142.5 922.7
143.0 912.4
143.5 901.4
144.0 889.7
144.5 876.9
145.0 862.9
OIML R 81: 1998 (E) 31

TABLE 2–a
HELIUM

K MPa kg/m3 dm3/kg
4.00 .0815 129.00 7.752

4.02 .0831 128.66 7.772
4.04 .0848 128.33 7.793
4.06 .0865 127.99 7.813
4.08 .0882 127.64 7.835
4.10 .0900 127.29 7.856
4.12 .0917 126.93 7.878
4.14 .0935 126.57 7.901
4.16 .0953 126.20 7.924
4.18 .0972 125.83 7.947
4.20 .0990 125.45 7.971
4.22 .1009 125.06 7.996
4.24 .1028 124.67 8.021
4.26 .1047 124.28 8.047
4.28 .1067 123.87 8.073
4.30 .1087 123.46 8.100
4.32 .1107 123.05 8.127
4.34 .1127 122.62 8.155
4.36 .1148 122.19 8.184
4.38 .1169 121.75 8.213
4.40 .1190 121.31 8.244
4.42 .1211 120.85 8.275
4.44 .1233 120.39 8.306
4.46 .1255 119.92 8.339
4.48 .1277 119.44 8.373
4.50 .1299 118.95 8.407
4.52 .1322 118.45 8.443
4.54 .1345 117.94 8.479
4.56 .1368 117.42 8.517
4.58 .1392 116.88 8.555
4.60 .1416 116.34 8.596
4.62 .1440 115.78 8.637
4.64 .1464 115.21 8.680
4.66 .1489 114.63 8.724
4.68 .1514 114.03 8.770
4.70 .1539 113.41 8.817
4.72 .1564 112.78 8.867
4.74 .1590 112.13 8.918
4.76 .1616 111.46 8.972
4.78 .1643 110.77 9.028
32 OIML R 81: 1998 (E)

HELIUM

K MPa kg/m3 dm3/kg
4.80 .1670 110.05 9.086

4.82 .1697 109.32 9.148
4.84 .1724 108.55 9.212
4.86 .1752 107.76 9.280
4.88 .1780 106.93 9.352
4.90 .1808 106.07 9.427
4.92 .1837 105.17 9.508
4.94 .1866 104.23 9.594
4.96 .1895 103.24 9.686
4.98 .1925 102.19 9.785
5.00 .1954 101.08 9.893
5.02 .1985 99.90 10.010
5.04 .2015 98.63 10.139
5.06 .2046 97.25 10.282
5.08 .2077 95.75 10.444
5.10 .2109 94.08 10.629
5.12 .2141 92.20 10.846
5.14 .2173 90.01 11.109
OIML R 81: 1998 (E) 33

TABLE 2–b HELIUM (Temperature: K Pressure: MPa Density: kg/m3)
PRES .085 .090 .100 .110 .120 .130 .140 .150 .160 .170 .180 .200 .220
TEMP
4.00 129.2 129.5 130.0 130.5 131.0 131.5 131.9 132.4 132.8 133.2 133.7 134.5 135.2
4.01 129.0 129.3 129.8 130.3 130.8 131.3 131.8 132.2 132.6 133.1 133.5 134.3 135.1
4.02 128.8 129.0 129.6 130.1 130.6 131.1 131.6 132.0 132.5 132.9 133.3 134.1 134.9
4.03 128.6 128.8 129.4 129.9 130.4 130.9 131.4 131.8 132.3 132.7 133.2 134.0 134.8
4.04 128.3 128.6 129.2 129.7 130.2 130.7 131.2 131.7 132.1 132.6 133.0 133.8 134.6
4.05 128.4 129.0 129.5 130.0 130.5 131.0 131.5 131.9 132.4 132.8 133.6 134.4
4.06 128.2 128.8 129.3 129.8 130.3 130.8 131.3 131.8 132.2 132.6 133.5 134.3
4.07 128.0 128.5 129.1 129.6 130.1 130.6 131.1 131.6 132.0 132.5 133.3 134.1
4.08 127.7 128.3 128.9 129.4 129.9 130.4 130.9 131.4 131.9 132.3 133.1 134.0
4.09 127.5 128.1 128.7 129.2 129.7 130.2 130.7 131.2 131.7 132.1 133.0 133.8
4.10 127.3 127.9 128.5 129.0 129.5 130.0 130.5 131.0 131.5 131.9 132.8 133.6
4.11 127.7 128.2 128.8 129.3 129.8 130.3 130.8 131.3 131.8 132.6 133.5
4.12 127.4 128.0 128.6 129.1 129.6 130.2 130.6 131.1 131.6 132.5 133.3
4.13 127.2 127.8 128.4 128.9 129.4 130.0 130.4 130.9 131.4 132.3 133.1
4.14 127.0 127.6 128.1 128.7 129.2 129.8 130.3 130.7 131.2 132.1 133.0
4.15 126.7 127.3 127.9 128.5 129.0 129.6 130.1 130.5 131.0 131.9 132.8
4.16 126.5 127.1 127.7 128.3 128.8 129.3 129.9 130.4 130.8 131.7 132.6
4.17 126.3 126.9 127.5 128.1 128.6 129.1 129.7 130.2 130.6 131.6 132.4
4.18 126.0 126.6 127.3 127.8 128.4 128.9 129.5 130.0 130.4 131.4 132.3
4.19 125.8 126.4 127.0 127.6 128.2 128.7 129.2 129.8 130.3 131.2 132.1
4.20 125.5 126.2 126.8 127.4 128.0 128.5 129.0 129.6 130.1 131.0 131.9
4.21 125.3 125.9 126.6 127.2 127.7 128.3 128.8 129.4 129.9 130.8 131.7
4.22 125.7 126.3 126.9 127.5 128.1 128.6 129.1 129.7 130.6 131.5
4.23 125.4 126.1 126.7 127.3 127.9 128.4 128.9 129.5 130.4 131.4
4.24 125.2 125.8 126.5 127.1 127.6 128.2 128.7 129.2 130.2 131.2
4.25 124.9 125.6 126.2 126.8 127.4 128.0 128.5 129.0 130.0 131.0
4.26 124.6 125.3 126.0 126.6 127.2 127.8 128.3 128.8 129.8 130.8
4.27 124.4 125.1 125.7 126.4 127.0 127.5 128.1 128.6 129.6 130.6
4.28 124.1 124.8 125.5 126.1 126.7 127.3 127.9 128.4 129.4 130.4
4.29 123.8 124.5 125.2 125.9 126.5 127.1 127.6 128.2 129.2 130.2
4.30 123.6 124.3 125.0 125.6 126.2 126.8 127.4 128.0 129.0 130.0
4.31 123.3 124.0 124.7 125.4 126.0 126.6 127.2 127.8 128.8 129.8
4.32 123.7 124.4 125.1 125.8 126.4 127.0 127.5 128.6 129.6
4.33 123.5 124.2 124.9 125.5 126.1 126.7 127.3 128.4 129.4
4.34 123.2 123.9 124.6 125.3 125.9 126.5 127.1 128.2 129.2
4.35 122.9 123.6 124.3 125.0 125.7 126.3 126.9 128.0 129.0
4.36 122.6 123.4 124.1 124.8 125.4 126.0 126.6 127.8 128.8
4.37 122.3 123.1 123.8 124.5 125.2 125.8 126.4 127.5 128.6
4.38 122.0 122.8 123.5 124.2 124.9 125.5 126.2 127.3 128.4
4.39 121.7 122.5 123.3 124.0 124.6 125.3 125.9 127.1 128.2
4.40 121.4 122.2 123.0 123.7 124.4 125.0 125.7 126.9 128.0
4.41 121.9 122.7 123.4 124.1 124.8 125.4 126.6 127.7
4.42 121.6 122.4 123.1 123.9 124.5 125.2 126.4 127.5
4.43 121.3 122.1 122.9 123.6 124.3 124.9 126.2 127.3
4.44 121.0 121.8 122.6 123.3 124.0 124.7 125.9 127.1
4.45 120.7 121.5 122.3 123.0 123.7 124.4 125.7 126.8
4.46 120.3 121.2 122.0 122.7 123.5 124.2 125.4 126.6
4.47 120.0 120.9 121.7 122.5 123.2 123.9 125.2 126.4
4.48 119.7 120.5 121.4 122.2 122.9 123.6 124.9 126.1
4.49 119.3 120.2 121.1 121.9 122.6 123.3 124.7 125.9
4.50 119.0 119.9 120.8 121.6 122.3 123.1 124.4 125.7
4.51 119.5 120.4 121.3 122.1 122.8 124.2 125.4
4.52 119.2 120.1 121.0 121.8 122.5 123.9 125.2
4.53 118.9 119.8 120.6 121.5 122.2 123.6 124.9
4.54 118.5 119.4 120.3 121.1 121.9 123.4 124.7
4.55 118.1 119.1 120.0 120.8 121.6 123.1 124.4
4.56 117.7 118.7 119.7 120.5 121.3 122.8 124.2
4.57 117.4 118.4 119.3 120.2 121.0 122.5 123.9
4.58 117.0 118.0 119.0 119.9 120.7 122.3 123.6
4.59 117.6 118.6 119.5 120.4 122.0 123.4
4.60 117.3 118.3 119.2 120.1 121.7 123.1
4.61 116.9 117.9 118.9 119.7 121.4 122.8
4.62 116.5 117.5 118.5 119.4 121.1 122.6
4.63 116.1 117.1 118.1 119.1 120.8 122.3
4.64 115.6 116.8 117.8 118.7 120.5 122.0
34 OIML R 81: 1998 (E)

TABLE 2–b (cont’d) HELIUM (Temperature: K Pressure: MPa Density: kg/m3)
PRES .085 .090 .100 .110 .120 .130 .140 .150 .160 .170 .180 .200 .220
TEMP
4.65 115.2 116.4 117.4 118.4 120.1 121.7
4.66 114.8 116.0 117.0 118.0 119.8 121.4
4.67 115.5 116.6 117.7 119.5 121.1
4.68 115.1 116.2 117.3 119.2 120.8
4.69 114.7 115.8 116.9 118.8 120.5
4.70 114.2 115.4 116.5 118.5 120.2
4.71 113.7 115.0 116.1 118.1 119.9
4.72 113.3 114.6 115.7 117.8 119.5
4.73 112.8 114.1 115.3 117.4 119.2
4.74 112.3 113.6 114.9 117.0 118.9
4.75 113.2 114.4 116.6 118.5
4.76 112.7 114.0 116.3 118.2
4.77 112.2 113.5 115.9 117.8
4.78 111.7 113.1 115.5 117.5
4.79 111.1 112.6 115.0 117.1
4.80 110.6 112.1 114.6 116.7
4.81 110.0 111.6 114.2 116.4
4.82 109.4 111.0 113.7 116.0
4.83 110.5 113.3 115.6
4.84 109.9 112.8 115.2
4.85 109.3 112.3 114.8
4.86 108.7 111.8 114.3
4.87 108.0 111.3 113.9
4.88 107.4 110.8 113.5
4.89 106.6 110.3 113.0
4.90 109.7 112.6
4.91 109.1 112.1
4.92 108.5 111.6
4.93 107.9 111.1
4.94 107.2 110.6
4.95 106.5 110.0
4.96 105.8 109.5
4.97 105.0 108.9
4.98 104.2 108.3
4.99 103.4 107.7
5.00 102.5 107.0
5.01 101.5 106.4
5.02 100.4 105.7
5.03 99.3 104.9
5.04 104.2
5.05 103.4
5.06 102.5
5.07 101.6
5.08 100.6
5.09 99.6
5.10 98.4
5.11 97.2
5.12 95.7
5.13 94.1
5.14 92.2
5.15 89.8
OIML R 81: 1998 (E) 35

TABLE 3–a
HYDROGEN

K MPa kg/m3 dm3/kg
19.4 .0774 71.77 13.934
19.6 .0824 71.55 13.976
19.8 .0877 71.33 14.019
20.0 .0933 71.11 14.063
20.2 .0990 70.88 14.107
20.4 .1051 70.66 14.153
20.6 .1114 70.43 14.199
20.8 .1179 70.19 14.246
21.0 .1247 69.96 14.294
21.2 .1319 69.72 14.343
21.4 .1392 69.48 14.393
21.6 .1469 69.23 14.444
21.8 .1549 68.98 14.496
22.0 .1632 68.73 14.550
22.2 .1718 68.47 14.604
22.4 .1807 68.22 14.659
22.6 .1900 67.95 14.716
22.8 .1995 67.69 14.774
23.0 .2094 67.42 14.833
23.2 .2197 67.14 14.894
23.4 .2303 66.86 14.956
23.6 .2412 66.58 15.020
23.8 .2525 66.29 15.085
24.0 .2642 66.00 15.151
24.2 .2763 65.70 15.220
24.4 .2887 65.40 15.290
24.6 .3016 65.10 15.361
24.8 .3148 64.79 15.435
25.0 .3284 64.47 15.511
25.2 .3425 64.15 15.589
25.4 .3570 63.82 15.669
25.6 .3718 63.49 15.751
25.8 .3872 63.15 15.836
26.0 .4029 62.80 15.923
26.2 .4191 62.45 16.013
26.4 .4358 62.09 16.105
26.6 .4529 61.73 16.201
26.8 .4704 61.35 16.299
36 OIML R 81: 1998 (E)

HYDROGEN

K MPa kg/m3 dm3/kg
27.0 .4885 60.97 16.402
27.2 .5070 60.58 16.507
27.4 .5260 60.18 16.617
27.6 .5456 59.77 16.730
27.8 .5656 59.35 16.848
28.0 .5861 58.93 16.971
28.2 .6072 58.49 17.098
28.4 .6287 58.03 17.231
28.6 .6509 57.57 17.370
28.8 .6735 57.09 17.516
29.0 .6967 56.60 17.669
29.2 .7205 56.09 17.829
29.4 .7449 55.56 17.998
29.6 .7698 55.02 18.176
29.8 .7953 54.45 18.365
30.0 .8214 53.86 18.566
30.2 .8482 53.25 18.780
30.4 .8755 52.60 19.010
30.6 .9035 51.93 19.256
30.8 .9322 51.22 19.522
31.0 .9615 50.48 19.811
31.2 .9915 49.68 20.127
31.4 1.0222 48.84 20.476
31.6 1.0535 47.92 20.867
31.8 1.0857 46.91 21.317
32.0 1.1185 45.74 21.863
32.2 1.1522 42.86 23.330
32.4 1.1866 39.99 25.007
32.6 1.2219 37.11 26.945
32.8 1.2581 34.24 29.209
OIML R 81: 1998 (E) 37

38 OIML R 81: 1998 (E)
TABLE 3–b HYDROGEN (Temperature: K Pressure: MPa Density: kg/m3)
PRES .08 .10 .20 .30 .40 .50 .60 .70 .80 .90 1.00 1.10 1.20
TEMP
19.4 71.77 71.80 71.93 72.05 72.18 72.30 72.42 72.54 72.66 72.78 72.89 73.01 73.12
19.6 71.57 71.70 71.83 71.96 72.09 72.21 72.33 72.45 72.57 72.69 72.80 72.92
19.8 71.35 71.48 71.61 71.74 71.87 72.00 72.12 72.24 72.36 72.48 72.60 72.72
20.0 71.12 71.25 71.39 71.52 71.65 71.78 71.90 72.03 72.15 72.27 72.40 72.51
20.2 70.89 71.02 71.16 71.30 71.43 71.56 71.69 71.81 71.94 72.06 72.19 72.31
20.4 70.79 70.93 71.07 71.20 71.34 71.47 71.60 71.72 71.85 71.98 72.10
20.6 70.55 70.70 70.84 70.97 71.11 71.24 71.38 71.51 71.63 71.76 71.89
20.8 70.31 70.46 70.60 70.74 70.88 71.02 71.15 71.29 71.42 71.54 71.67
21.0 70.07 70.22 70.36 70.51 70.65 70.79 70.93 71.06 71.19 71.33 71.46
21.2 69.82 69.97 70.12 70.27 70.41 70.56 70.70 70.83 70.97 71.10 71.24
21.4 69.57 69.73 69.88 70.03 70.18 70.32 70.46 70.60 70.74 70.88 71.01
21.6 69.31 69.47 69.63 69.78 69.93 70.08 70.23 70.37 70.51 70.65 70.79
21.8 69.05 69.22 69.38 69.53 69.69 69.84 69.99 70.13 70.28 70.42 70.56
22.0 68.79 68.96 69.12 69.28 69.44 69.59 69.74 69.89 70.04 70.18 70.33
22.2 68.52 68.69 68.86 69.02 69.18 69.34 69.50 69.65 69.80 69.95 70.09
22.4 68.25 68.42 68.59 68.76 68.93 69.09 69.25 69.40 69.56 69.71 69.85
22.6 67.97 68.15 68.32 68.50 68.66 68.83 68.99 69.15 69.31 69.46 69.61
22.8 67.68 67.87 68.05 68.23 68.40 68.57 68.73 68.90 69.06 69.21 69.37
23.0 67.58 67.77 67.95 68.13 68.30 68.47 68.64 68.80 68.96 69.12
23.2 67.29 67.48 67.67 67.85 68.03 68.21 68.38 68.54 68.71 68.87
23.4 67.00 67.19 67.39 67.57 67.76 67.93 68.11 68.28 68.45 68.61
23.6 66.70 66.90 67.10 67.29 67.48 67.66 67.84 68.01 68.19 68.35
23.8 66.39 66.60 66.80 67.00 67.19 67.38 67.56 67.74 67.92 68.09
24.0 66.08 66.29 66.50 66.70 66.90 67.09 67.28 67.47 67.65 67.82
24.2 65.76 65.98 66.19 66.40 66.61 66.80 67.00 67.19 67.37 67.55
24.4 65.43 65.66 65.88 66.09 66.30 66.51 66.71 66.90 67.09 67.28
24.6 65.33 65.56 65.78 66.00 66.21 66.41 66.61 66-81 67.00
24.8 64.99 65.23 65.46 65.68 65.90 66.11 66.32 66.52 66.71
25.0 64.65 64.90 65.13 65.36 65.59 65.80 66.01 66.22 66.42
25.2 64.30 64.55 64.80 65.04 65.27 65.49 65.71 65.92 66.12
25.4 63.94 64.20 64.46 64.70 64.94 65.17 65.40 65.61 65.82
25.6 63.57 63.84 64.11 64.36 64.61 64.85 65.08 65.30 65.52
25.8 63.19 63.47 63.75 64.01 64.27 64.51 64.75 64.98 65.21
26.0 63.09 63.38 63.65 63.92 64.17 64.42 64.66 64.89
26.2 62.70 63.00 63.29 63.56 63.83 64.08 64.33 64.57
26.4 62.30 62.61 62.91 63.20 63.47 63.73 63.99 64.23
26.6 61.88 62.21 62.52 62.82 63.10 63.38 63.64 63.90
26.8 61.45 61.80 62.12 62.43 62.73 63.02 63.29 63.55
27.0 61.01 61.37 61.71 62.04 62.35 62.64 62.93 63.20
27.2 60.93 61.29 61.63 61.95 62.26 62.56 62.84
27.4 60.47 60.85 61.21 61.55 61.87 62.17 62.47
27.6 60.00 60.40 60.77 61.13 61.46 61.78 62.09
27.8 59.50 59.93 60.32 60.70 61.05 61.38 61.70
28.0 58.99 59.44 59.86 60.25 60.62 60.97 61.30
28.2 58.93 59.37 59.79 60.18 60.55 60.89
28.4 58.39 58.87 59.31 59.72 60.11 60.47
28.6 57.83 58.34 58.81 59.25 59.65 60.04
28.8 57.24 57.79 58.29 58.75 59.19 59.59
29.0 56.61 57.21 57.75 58.24 58.70 59.12
29.2 56.59 57.18 57.71 58.19 58.64
29.4 55.94 56.58 57.15 57.67 58.15
29.6 55.24 55.94 56.56 57.12 57.63
29.8 54.48 55.26 55.94 56.54 57.09
30.0 54.53 55.28 55.93 56.52
30.2 53.73 54.57 55.29 55.93
30.4 52.86 53.81 54.60 55.30
30.6 52.98 53.87 54.64
30.8 52.06 53.08 53.93
31.0 51.02 52.21 53.17
31.2 49.81 51.25 52.35
31.4 50.15 51.44
31.6 48.86 50.44
31.8 47.25 49.29
32.0 47.93
OIML R 81: 1998 (E) 39

TABLE 4–a
NITROGEN

K MPa kg/m3 dm3/kg
75.0 .0760 819.3 1.221
76.0 .0860 814.8 1.227
77.0 .0971 810.3 1.234
78.0 .1091 805.7 1.241
79.0 .1223 801.1 1.248
80.0 .1367 796.4 1.256
81.0 .1523 791.6 1.263
82.0 .1692 786.8 1.271
83.0 .1875 782.0 1.279
84.0 .2072 777.0 1.287
85.0 .2284 772.0 1.295
86.0 .2512 767.0 1.304
87.0 .2757 761.9 1.313
88.0 .3019 756.7 1.322
89.0 .3299 751.4 1.331
90.0 .3597 746.1 1.340
91.0 .3915 740.7 1.350
92.0 .4254 735.3 1.360
93.0 .4613 729.7 1.370
94.0 .4994 724.1 1.381
95.0 .5397 718.4 1.392
96.0 .5823 712.6 1.403
97.0 .6274 706.8 1.415
98.0 .6749 700.8 1.427
99.0 .7250 694.8 1.439
100.0 .7777 688.6 1.452
101.0 .8331 682.4 1.465
102.0 .8913 676.0 1.479
103.0 .9524 669.6 1.493
104.0 1.0164 663.0 1.508
105.0 1.0835 656.2 1.524
106.0 1.1537 649.4 1.540
107.0 1.2270 642.3 1.557
108.0 1.3037 635.1 1.575
109.0 1.3837 627.7 1.593
110.0 1.4672 620.1 1.613
111.0 1.5543 612.3 1.633
112.0 1.6450 604.3 1.655
113.0 1.7394 595.9 1.678
114.0 1.8376 587.3 1.703
40 OIML R 81: 1998 (E)

NITROGEN

K MPa kg/m3 dm3/kg
115.0 1.9398 578.2 1.729
116.0 2.0460 568.8 1.758
117.0 2.1564 558.9 1.789
118.0 2.2709 548.4 1.823
119.0 2.3899 537.2 1.861
120.0 2.5133 525.2 1.904
121.0 2.6414 512.0 1.953
122.0 2.7742 497.2 2.011
123.0 2.9120 480.1 2.083
124.0 3.0550 458.9 2.179
125.0 3.2034 429.5 2.328
126.0 3.3578 442.6 2.259
OIML R 81: 1998 (E) 41

TABLE 4–b NITROGEN (Temperature: K Pressure: MPa Density: kg/m3)
PRES .08 .10 .20 .40 .60 .80 1.00 1.25 1.50 1.75 2.00 2.50 3.00
TEMP
75.0 819.3 819.3 819.6 820.0 820.4 820.8 821.2 821.8 822.3 822.8 823.3 824.3 825.3
75.5 817.1 817.3 817.8 818.2 818.6 819.0 819.6 820.1 820.6 821.1 822.2 823.2
76.0 814.8 815.1 815.5 815.9 816.4 816.8 817.4 817.9 818.4 819.0 820.0 821.1
76.5 812.6 812.8 813.2 813.7 814.1 814.6 815.1 815.7 816.2 816.8 817.9 818.9
77.0 810.3 810.5 811.0 811.4 811.9 812.3 812.9 813.5 814.0 814.6 815.7 816.8
77.5 808.2 808.7 809.2 809.6 810.1 810.7 811.2 811.8 812.4 813.5 814.6
78.0 805.9 806.4 806.9 807.3 807.8 808.4 809.0 809.6 810.1 811.3 812.4
78.5 803.6 804.1 804.5 805.0 805.5 806.1 806.7 807.3 807.9 809.1 810.2
79.0 801.2 801.7 802.2 802.7 803.2 803.8 804.4 805.0 805.6 806.8 808.0
79.5 798.9 799.4 799.9 800.4 800.9 801.5 802.1 802.8 803.4 804.6 805.8
80.0 796.5 797.0 797.5 798.1 798.6 799.2 799.8 800.5 801.1 802.3 803.6
80.5 794.1 794.6 795.2 795.7 796.2 796.9 797.5 798.2 798.8 800.1 801.3
81.0 791.7 792.2 792.8 793.3 793.9 794.5 795.2 795.8 796.5 797.8 799.1
81.5 789.3 789.8 790.4 790.9 791.5 792.2 792.8 793.5 794.2 795.5 796.8
82.0 786.8 787.4 788.0 788.5 789.1 789.8 790.5 791.2 791.8 793.2 794.5
82.5 784.4 785.0 785.5 786.1 786.7 787.4 788.1 788.8 789.5 790.9 792.2
83.0 781.9 782.5 783.1 783.7 784.3 785.0 785.7 786.4 787.1 788.5 789.9
83.5 779.4 780.0 780.6 781.2 781.8 782.6 783.3 784.0 784.8 786.2 787.6
84.0 777.5 778.1 778.8 779.4 780.1 780.9 781.6 782.4 783.8 785.3
84.5 775.0 775.7 776.3 776.9 777.7 778.4 779.2 780.0 781.4 782.9
85.0 772.5 773.1 773.8 774.4 775.2 776.0 776.8 777.5 779.1 780.5
85.5 770.0 770.6 771.3 771.9 772.7 773.5 774.3 775.1 776.6 778.2
86.0 767.4 768.1 768.7 769.4 770.2 771.0 771.8 772.6 774.2 775.8
86.5 764.8 765.5 766.2 766.9 767.7 768.5 769.4 770.2 771.8 773.4
87.0 762.2 762.9 763.6 764.3 765.2 766.0 766.9 767.7 769.3 771.0
87.5 759.6 760.3 761.0 761.7 762.6 763.5 764.4 765.2 766.9 768.5
88.0 757.0 757.7 758.4 759.2 760.1 760.9 761.8 762.7 764.4 766.1
88.5 754.3 755.1 755.8 756.6 757.5 758.4 759.3 760.2 761.9 763.6
89.0 751.6 752.4 753.2 753.9 754.9 755.8 756.7 757.6 759.4 761.1
89.5 748.9 749.7 750.5 751.3 752.2 753.2 754.1 755.0 756.9 758.6
90.0 746.2 747.0 747.8 748.6 749.6 750.6 751.5 752.5 754.3 756.1
90.5 743.5 744.3 745.1 745.9 746.9 747.9 748.9 749.9 751.8 753.6
91.0 740.7 741.6 742.4 743.2 744.2 745.3 746.3 747.2 749.2 751.1
91.5 738.8 739.7 740.5 741.5 742.6 743.6 744.6 746.6 748.5
92.0 736.0 736.9 737.8 738.8 739.9 740.9 741.9 744.0 745.9
92.5 733.2 734.1 735.0 736.1 737.2 738.2 739.3 741.3 743.4
93.0 730.4 731.3 732.2 733.3 734.4 735.5 736.6 738.7 740.7
93.5 727.5 728.4 729.4 730.5 731.6 732.8 733.9 736.0 738.1
94.0 724.6 725.6 726.5 727.7 728.9 730.0 731.1 733.3 735.5
94.5 721.7 722.7 723.7 724.9 726.0 727.2 728.4 730.6 732.8
95.0 718.8 719.8 720.8 722.0 723.2 724.4 725.6 727.9 730.1
95.5 715.8 716.8 717.8 719.1 720.3 721.6 722.8 725.1 727.4
96.0 712.8 713.8 714.9 716.2 717.5 718.7 719.9 722.4 724.7
96.5 710.8 711.9 713.2 714.5 715.8 717.1 719.6 721.9
97.0 707.8 708.9 710.3 711.6 712.9 714.2 716.7 719.2
97.5 704.7 705.9 707.3 708.6 710.0 711.3 713.9 716.4
98.0 701.6 702.8 704.2 705.6 707.0 708.4 711.0 713.6
98.5 698.5 699.7 701.2 702.6 704.0 705.4 708.1 710.7
99.0 695.3 696.5 698.1 699.5 701.0 702.4 705.2 707.9
99.5 692.1 693.4 694.9 696.4 697.9 699.4 702.2 705.0
100.0 688.8 690.2 691.7 693.3 694.8 696.3 699.3 702.1
100.5 686.9 688.5 690.1 691.7 693.3 696.3 699.1
101.0 683.6 685.3 686.9 688.6 690.1 693.2 696.2
101.5 680.3 682.0 683.7 685.4 687.0 690.2 693.2
102.0 676.9 678.7 680.4 682.1 683.8 687.1 690.2
102.5 673.5 675.3 677.1 678.9 680.6 683.9 687.1
103.0 670.0 671.9 673.7 675.6 677.3 680.8 684.0
103.5 666.4 668.4 670.3 672.2 674.0 677.6 680.9
104.0 664.9 666.9 668.8 670.7 674.3 677.8
104.5 661.3 663.4 665.4 667.3 671.0 674.6
105.0 657.7 659.8 661.9 663.9 667.7 671.4
105.5 654.0 656.2 658.3 660.4 664.3 668.1
42 OIML R 81: 1998 (E)

TABLE 4–b (cont’d) NITROGEN (Temperature: K Pressure: MPa Density: kg/m3)
PRES .08 .10 .20 .40 .60 .80 1.00 1.25 1.50 1.75 2.00 2.50 3.00
TEMP
106.0 650.3 652.5 654.7 656.9 660.9 664.8
106.5 646.4 648.8 651.1 653.3 657.5 661.5
107.0 642.5 645.0 647.3 649.6 654.0 658.1
107.5 641.1 643.6 645.9 650.4 654.7
108.0 637.2 639.7 642.2 646.8 651.2
108.5 633.1 635.8 638.3 643.2 647.7
109.0 629.0 631.8 634.4 639.4 644.1
109.5 624.8 627.7 630.4 635.6 640.5
110.0 620.5 623.5 626.4 631.8 636.8
110.5 619.2 622.2 627.9 633.1
111.0 614.8 618.0 623.8 629.2
111.5 610.3 613.6 619.8 625.4
112.0 605.7 609.2 615.6 621.4
112.5 600.9 604.6 611.3 617.4
113.0 596.0 599.9 606.9 613.3
113.5 595.0 602.4 609.1
114.0 590.0 597.8 604.8
114.5 584.8 593.1 600.4
115.0 579.4 588.2 595.9
115.5 573.7 583.2 591.3
116.0 577.9 586.5
116.5 572.5 581.6
117.0 566.8 576.6
117.5 560.8 571.3
118.0 554.5 565.9
118.5 547.9 560.2
119.0 540.8 554.2
119.5 533.1 548.0
120.0 541.4
120.5 534.3
121.0 526.7
121.5 518.5
122.0 509.4
122.5 499.0
123.0 486.9
OIML R 81: 1998 (E) 43

TABLE 5–a
OXYGEN

K MPa kg/m3 dm3/kg
88.0 .0801 1151.9 .8682
89.0 .0893 1147.0 .8719
90.0 .0993 1142.0 .8756
91.0 .1102 1137.0 .8795
92.0 .1219 1132.0 .8834
93.0 .1346 1127.0 .8873
94.0 .1483 1121.9 .8913
95.0 .1631 1116.8 .8954
96.0 .1789 1111.7 .8995
97.0 .1958 1106.5 .9037
98.0 .2139 1101.3 .9080
99.0 .2333 1096.1 .9123
100.0 .2540 1090.8 .9167
101.0 .2760 1085.5 .9212
102.0 .2994 1080.1 .9258
103.0 .3243 1074.7 .9305
104.0 .3506 1069.3 .9352
105.0 .3785 1063.8 .9401
106.0 .4081 1058.2 .9450
107.0 .4392 1052.6 .9500
108.0 .4722 1046.9 .9552
109.0 .5069 1041.2 .9604
110.0 .5434 1035.4 .9658
111.0 .5818 1029.6 .9712
112.0 .6222 1023.7 .9768
113.0 .6646 1017.7 .9826
114.0 .7090 1011.7 .9884
115.0 .7556 1005.6 .9944
116.0 .8043 999.4 1.0006
117.0 .8553 993.2 1.0069
118.0 .9085 986.8 1.0134
119.0 .9642 980.4 1.0200
120.0 1.0222 973.9 1.0268
121.0 1.0827 967.2 1.0339
122.0 1.1458 960.5 1.0411
123.0 1.2114 953.7 1.0485
124.0 1.2797 946.8 1.0562
44 OIML R 81: 1998 (E)

OXYGEN

K MPa kg/m3 dm3/kg
125.0 1.3507 939.7 1.0642
126.0 1.4245 932.5 1.0723
127.0 1.5012 925.2 1.0808
128.0 1.5807 917.8 1.0896
129.0 1.6633 910.2 1.0987
130.0 1.7488 902.4 1.1081
131.0 1.8375 894.5 1.1179
132.0 1.9294 886.4 1.1282
133.0 2.0245 878.1 1.1388
134.0 2.1229 869.6 1.1500
135.0 2.2248 860.9 1.1616
136.0 2.3301 851.9 1.1738
137.0 2.4389 842.7 1.1867
138.0 2.5514 833.2 1.2002
139.0 2.6676 823.3 1.2146
140.0 2.7875 813.2 1.2298
141.0 2.9114 802.6 1.2459
142.0 3.0392 791.6 1.2632
143.0 3.1711 780.2 1.2818
144.0 3.3072 768.2 1.3018
145.0 3.4476 755.5 1.3236
146.0 3.5924 742.2 1.3474
147.0 3.7417 727.9 1.3738
148.0 3.8958 712.6 1.4033
149.0 4.0547 695.9 1.4369
150.0 4.2186 677.5 1.4760
151.0 4.3878 656.6 1.5230
152.0 4.5625 631.8 1.5828
153.0 4.7432 599.9 1.6670
154.0 4.9305 550.3 1.8173
OIML R 81: 1998 (E) 45

TABLE 5–b OXYGEN (Temperature: K Pressure: MPa Density: kg/m3)
PRES .08 .10 .20 .40 .60 .80 1.00 1.50 2.00 2.50 3.00 3.50 4.00
TEMP
88.0 1151.9 1152.1 1152.5 1152.9 1153.4 1153.8 1154.8 1155.9 1156.9 1157.9 1158.9 1160.0
88.5 1149.4 1149.6 1150.1 1150.5 1150.9 1151.3 1152.4 1153.4 1154.5 1155.5 1156.6 1157.6
89.0 1146.9 1147.2 1147.6 1148.0 1148.5 1148.9 1150.0 1151.0 1152.1 1153.1 1154.2 1155.2
89.5 1144.5 1144.7 1145.1 1145.5 1146.0 1146.4 1147.5 1148.6 1149.6 1150.7 1151.8 1152.8
90.0 1142.0 1142.2 1142.6 1143.1 1143.5 1144.0 1145.0 1146.1 1147.2 1148.3 1149.4 1150.4
90.5 1139.7 1140.1 1140.6 1141.0 1141.5 1142.6 1143.7 1144.8 1145.9 1146.9 1148.0
91.0 1137.2 1137.6 1138.1 1138.5 1139.0 1140.1 1141.2 1142.3 1143.4 1144.5 1145.6
91.5 1134.7 1135.1 1135.6 1136.1 1136.5 1137.6 1138.8 1139.9 1141.0 1142.1 1143.2
92.0 1132.2 1132.6 1133.1 1133.5 1134.0 1135.2 1136.3 1137.4 1138.5 1139.7 1140.8
92.5 1129.6 1130.1 1130.6 1131.0 1131.5 1132.7 1133.8 1135.0 1136.1 1137.2 1138.3
93.0 1127.1 1127.6 1128.0 1128.5 1129.0 1130.2 1131.3 1132.5 1133.6 1134.8 1135.9
93.5 1124.5 1125.0 1125.5 1126.0 1126.5 1127.7 1128.8 1130.0 1131.2 1132.3 1133.5
94.0 1122.0 1122.5 1123.0 1123.5 1123.9 1125.1 1126.3 1127.5 1128.7 1129.9 1131.0
94.5 1119.4 1119.9 1120.4 1120.9 1121.4 1122.6 1123.8 1125.0 1126.2 1127.4 1128.6
95.0 1116.9 1117.4 1117.9 1118.4 1118.9 1120.1 1121.3 1122.5 1123.7 1124.9 1126.1
95.5 1114.3 1114.8 1115.3 1115.8 1116.3 1117.5 1118.8 1120.0 1121.2 1122.4 1123.6
96.0 1111.7 1112.2 1112.7 1113.2 1113.7 1115.0 1116.3 1117.5 1118.7 1119.9 1121.2
96.5 1109.1 1109.6 1110.1 1110.6 1111.2 1112.4 1113.7 1115.0 1116.2 1117.4 1118.7
97.0 1106.5 1107.0 1107.5 1108.1 1108.6 1109.9 1111.2 1112.4 1113.7 1114.9 1116.2
97.5 1104.4 1104.9 1105.5 1106.0 1107.3 1108.6 1109.9 1111.2 1112.4 1113.7
98.0 1101.8 1102.3 1102.8 1103.4 1104.7 1106.0 1107.3 1108.6 1109.9 1111.2
98.5 1099.1 1099.7 1100.2 1100.8 1102.1 1103.4 1104.8 1106.1 1107.4 1108.7
99.0 1096.5 1097.0 1097.6 1098.1 1099.5 1100.9 1102.2 1103.5 1104.8 1106.1
99.5 1093.8 1094.4 1094.9 1095.5 1096.9 1098.3 1099.6 1101.0 1102.3 1103.6
100.0 1091.2 1091.7 1092.3 1092.9 1094.3 1095.6 1097.0 1098.4 1099.7 1101.1
100.5 1088.5 1089.1 1089.6 1090.2 1091.6 1093.0 1094.4 1095.8 1097.2 1098.5
101.0 1085.8 1086.4 1086.9 1087.5 1089.0 1090.4 1091.8 1093.2 1094.6 1095.9
101.5 1083.1 1083.7 1084.3 1084.8 1086.3 1087.8 1089.2 1090.6 1092.0 1093.4
102.0 1080.4 1081.0 1081.6 1082.2 1083.6 1085.1 1086.5 1088.0 1089.4 1090.8
102.5 1077.6 1078.2 1078.8 1079.5 1081.0 1082.4 1083.9 1085.4 1086.8 1088.2
103.0 1074.9 1075.5 1076.1 1076.7 1078.3 1079.8 1081.2 1082.7 1084.2 1085.6
103.5 1072.1 1072.8 1073.4 1074.0 1075.5 1077.1 1078.6 1080.1 1081.5 1083.0
104.0 1069.4 1070.0 1070.6 1071.3 1072.8 1074.4 1075.9 1077.4 1078.9 1080.4
104.5 1066.6 1067.2 1067.9 1068.5 1070.1 1071.7 1073.2 1074.7 1076.3 1077.7
105.0 1063.8 1064.4 1065.1 1065.7 1067.3 1068.9 1070.5 1072.1 1073.6 1075.1
105.5 1061.0 1061.6 1062.3 1062.9 1064.6 1066.2 1067.8 1069.4 1070.9 1072.5
106.0 1058.8 1059.5 1060.1 1061.8 1063.4 1065.1 1066.7 1068.2 1069.8
106.5 1056.0 1056.6 1057.3 1059.0 1060.7 1062.3 1063.9 1065.5 1067.1
107.0 1053.1 1053.8 1054.5 1056.2 1057.9 1059.6 1061.2 1062.8 1064.4
107.5 1050.2 1051.0 1051.7 1053.4 1055.1 1056.8 1058.5 1060.1 1061.7
108.0 1047.4 1048.1 1048.8 1050.6 1052.3 1054.0 1055.7 1057.4 1059.0
108.5 1044.5 1045.2 1045.9 1047.7 1049.5 1051.2 1052.9 1054.6 1056.3
109.0 1041.5 1042.3 1043.0 1044.8 1046.6 1048.4 1050.1 1051.9 1053.6
109.5 1038.6 1039.4 1040.1 1042.0 1043.8 1045.6 1047.3 1049.1 1050.8
110.0 1035.6 1036.4 1037.2 1039.0 1040.9 1042.7 1044.5 1046.3 1048.0
110.5 1032.7 1033.4 1034.2 1036.1 1038.0 1039.9 1041.7 1043.5 1045.3
111.0 1029.7 1030.5 1031.3 1033.2 1035.1 1037.0 1038.8 1040.7 1042.5
111.5 1027.5 1028.3 1030.2 1032.2 1034.1 1036.0 1037.8 1039.7
112.0 1024.4 1025.3 1027.3 1029.2 1031.2 1033.1 1035.0 1036.8
112.5 1021.4 1022.2 1024.3 1026.3 1028.3 1030.2 1032.1 1034.0
113.0 1018.3 1019.2 1021.3 1023.3 1025.3 1027.3 1029.2 1031.1
113.5 1015.2 1016.1 1018.2 1020.3 1022.3 1024.3 1026.3 1028.3
114.0 1012.1 1013.0 1015.2 1017.3 1019.4 1021.4 1023.4 1025.4
114.5 1009.0 1009.9 1012.1 1014.2 1016.3 1018.4 1020.5 1022.5
115.0 1005.8 1006.7 1009.0 1011.2 1013.3 1015.4 1017.5 1019.6
115.5 1002.6 1003.6 1005.9 1008.1 1010.3 1012.4 1014.5 1016.6
116.0 1000.4 1002.7 1005.0 1007.2 1009.4 1011.5 1013.7
116.5 997.2 999.5 1001.8 1004.1 1006.3 1008.5 1010.7
117.0 993.9 996.3 998.7 1001.0 1003.3 1005.5 1007.7
117.5 990.6 993.1 995.5 997.9 1000.2 1002.4 1004.7
118.0 987.3 989.8 992.3 994.7 997.1 999.4 1001.6
118.5 984.0 986.6 989.1 991.5 993.9 996.3 998.6
119.0 980.6 983.3 985.8 988.3 990.7 993.1 995.5
119.5 977.2 979.9 982.5 985.1 987.6 990.0 992.4
46 OIML R 81: 1998 (E)

TABLE 5–b (cont’d) OXYGEN (Temperature: K Pressure: MPa Density: kg/m3)
PRES .08 .10 .20 .40 .60 .80 1.00 1.50 2.00 2.50 3.00 3.50 4.00
TEMP
120.0 976.5 979.2 981.8 984.3 986.8 989.3
120.5 973.1 975.9 978.5 981.1 983.6 986.1
121.0 969.7 972.5 975.2 977.8 980.4 982.9
121.5 966.2 969.1 971.8 974.5 977.2 979.7
122.0 962.7 965.6 968.4 971.2 973.9 976.5
122.5 959.2 962.1 965.0 967.8 970.6 973.3
123.0 955.6 958.6 961.6 964.4 967.2 970.0
123.5 951.9 955.1 958.1 961.0 963.9 966.7
124.0 948.3 951.5 954.6 957.6 960.5 963.3
124.5 944.6 947.8 951.0 954.1 957.1 960.0
125.0 940.8 944.2 947.4 950.6 953.6 956.6
125.5 937.0 940.4 943.8 947.0 950.1 953.1
126.0 933.1 936.7 940.1 943.4 946.6 949.7
126.5 929.2 932.9 936.4 939.7 943.0 946.2
127.0 929.0 932.6 936.1 939.4 942.7
127.5 925.1 928.8 932.3 935.8 939.1
128.0 921.1 924.9 928.6 932.1 935.5
128.5 917.1 921.0 924.7 928.4 931.8
129.0 913.0 917.0 920.9 924.6 928.2
129.5 908.9 913.0 917.0 920.8 924.4
130.0 904.7 908.9 913.0 916.9 920.7
130.5 900.4 904.8 909.0 913.0 916.8
131.0 896.0 900.6 904.9 909.0 913.0
131.5 891.6 896.3 900.7 905.0 909.1
132.0 887.1 891.9 896.5 900.9 905.1
132.5 882.5 887.5 892.3 896.8 901.1
133.0 883.0 887.9 892.6 897.0
133.5 878.4 883.5 888.3 892.9
134.0 873.8 879.0 884.0 888.7
134.5 869.0 874.4 879.6 884.4
135.0 864.1 869.8 875.1 880.1
135.5 859.1 865.0 870.5 875.7
136.0 854.0 860.2 865.9 871.2
136.5 848.8 855.2 861.1 866.7
137.0 843.5 850.1 856.3 862.1
137.5 838.0 844.9 851.4 857.3
138.0 839.6 846.3 852.5
138.5 834.1 841.2 847.6
139.0 828.5 835.9 842.6
139.5 822.8 830.4 837.5
140.0 816.8 824.9 832.2
140.5 810.6 819.2 826.9
141.0 804.2 813.3 821.4
141.5 797.6 807.2 815.7
142.0 800.9 809.9
142.5 794.4 803.9
143.0 787.6 797.7
143.5 780.5 791.3
144.0 773.1 784.6
144.5 765.3 777.7
145.0 757.1 770.5
145.5 763.0
146.0 755.0
146.5 746.6
147.0 737.6
147.5 727.9
148.0 717.4
OIML R 81: 1998 (E) 47

OIML R 81: 1998 (E)
BIBLIOGRAPHY
IEC 60068-1 (1988) IEC 61000-4-3 (1995)

Environmental testing. Part 1: General and guidance. Electromagnetic compatibility (EMC). Part 4: Testing and
measurement techniques. Section 3: Radiated, radio-
IEC 60068-2-1 (1990) frequency, electromagnetic field immunity test.
Basic environmental testing procedures. Part 2: Tests. IEC 61000-4-4 (1995)

Test A: Cold. Electromagnetic compatibility (EMC). Part 4: Testing and
measurement techniques. Section 4: Electrical fast
IEC 60068-2-2 (1974)
transient/burst immunity test. Basic EMC Publication.
Basic environmental testing procedures. Part 2: Tests.
Test B: Dry heat. IEC 61000-4-11 (1994)
Electromagnetic compatibility (EMC). Part 4: Testing and

IEC 60068-2-6 (1995)
measurement techniques. Section 11: Voltage dips, short
Basic environmental testing procedures. Part 2: Tests. interruptions and voltage variations immunity tests.
Test Fc: Vibration (sinusoidal).
ISO 6551: 1982
IEC 60068-2-28 (1990)
Petroleum liquids and gases– Fidelity and security of
Basic environmental testing procedures. Part 2: Tests. dynamic measurement– Cabled transmission of electric
Guidance for damp heat tests. and/or electronic pulsed data.
IEC 60068-2-30 (1980) ISO 7637-1: 1990

Basic environmental testing procedures. Part 2: Tests. Road vehicles– Electrical disturbance by conduction and
Guidance for damp heat tests. Test Db and guid- coupling–
ance: Damp heat, cyclic (12 + 12-hour cycle). Part 1: Passenger cars and light commercial vehicles with
nominal 12 V supply voltage– Electrical transient
IEC 60068-3-1 (1974) conduction along supply lines only.
Basic environmental testing procedures. Part 3: Back- ISO 7637-2: 1990

ground information. Section 1 - Cold and dry heat tests.
Road vehicles– Electrical disturbance by conduction and
IEC 60068-3-1A (1978) coupling–
Part 2: Commercial vehicles with nominal 24 V supply
Basic environmental testing procedures. Part 3: Back- voltage– Electrical transient conduction along supply
ground information - First supplement. lines only.
IEC 61000-4-2 (1995) International Vocabulary of Basic and General Terms in

Metrology (VIM), Second edition, 1993.
Electromagnetic compatibility (EMC). Part 4: Testing and
measurement techniques. Section 2: Electrostatic dis- Guide to the Expression of Uncertainty in Measurement
charge immunity test. Basic EMC Publication. (GUM), First edition, 1995

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INTERNATIONAL OIML R 81

RECOMMENDATION Edition 1998 (E)

Dynamic measuring devices and systems

Dispositifs et systèmes de mesure dynamique de liquides cryogéniques

SECTION II - METROLOGICAL REQUIREMENTS

6 Maximum permissible errors (mpe) ................................................................................................................. 7

SECTION III - TECHNICAL REQUIREMENTS

9 Indicating devices (indicators) ......................................................................................................................... 8

SECTION IV - MEASURING SYSTEMS EQUIPPED WITH ELECTRONIC DEVICES

14 Measuring systems equipped with electronic devices ................................................................................... 10

SECTION V - METROLOGICAL CONTROLS

15 General requirements ...................................................................................................................................... 12

Annex A Test procedures. Performance tests - general .......................................................................................... 18

Printed in France GRANDE IMPRIMERIE DE TROYES

OIML Draft Recommendations and Documents are

Dynamic measuring devices and systems

Section I 3.1 Cryogenic liquid

Note: This is usually referred to as “master meter” in

2.1 This Recommendation applies to devices used 3.4 Measuring system

A part of the meter that transforms the flow of the

3.7 Calculator 3.13 Minimum measured quantity of a

3.12 Empty-hose type or dry-hose The ability of a measuring instrument to provide

3.20 Intrinsic error 3.26 Influence factor

3.23 Fault* An automatic checking facility that operates during

Note: Indications other than primary indications are Section II

6.5 Repeatability (3.19). The difference between the

8.1 The minimum measured quantity of the system

9.3 Totalizing indicator

9 Indicating devices (indicators)

9.1 General provisions 10 Printing devices (printers)

11.4 Memory devices 12.4 Transfer point

Section IV 14.1.5 When a significant fault occurs, measuring

14.2 Power supply device

A new pattern approval has to be issued when the

system. At this stage, the metrological examinations 15.3 Subsequent verification

15.2.2 Tests Care shall be exercised to reduce vaporization and

These tests should be applied uniformly by the legal A.1.3 Liquids

B.2 Severity levels (see OIML D 11)

Summary of performance tests

B.4.2 Cold Influence factor 2 3 3

B.4.3 Damp heat, cyclic Influence factor 1 2 2

B.4.4 Vibration Influence factor - - 3

B.4.7 Bursts Disturbance 2 2 2

B.4.8 Electrostatic Disturbance 1 1 1

B.4.1 Dry heat Background information concerning dry heat tests is

References Damp heat, cyclic (condensing).

IEC Publication 60068-2-1, 1990, Basic environmental Object of the test

Test procedure in brief Test procedure in brief

1) Upper temperature: severity level 1: 40 °C; Number of test cycles

B.4.5.1 AC power supply

Object of the test To verify compliance with the provisions in subclause

References The test consists of exposing the EUT to power voltage

Test severity B.4.6 Short time power reduction (not applicable

Number of test cycles Short time interruptions and reductions of mains

Maximum allowable variations To verify compliance with the provisions in subclause

Test method Test procedure in brief

B.4.7 Bursts (not applicable to systems with a DC B.4.8 Electrostatic discharge

b) For non-interruptible measuring systems, the Test severity