GCC STANDARDIZATION ORGANIZATION (GSO)  
 
 
 
 
 
 
FINAL   STANDARD  
 
 
GSO /04/FDS /OIML R 80-1:2014  
OIMLR 80-1:2010 
 
 
 
Rod and rail tankers with ievel gauging  
Par 1: Metroligical and technical requirements  
 
 
 
 
 
Prepared By  
Gulf Technical committee for Metrology Standards  
 
This document is a draft Gulf standard circulated for comment. It is, there for 
subjected to change and may not be referred to as GSO Standard until approved 
by the Board of Directors . 
ICS  : 17.100 GSO /04 /FDS/OIM LR80-1  
Foreword 
GCC Standardization Organization (GSO) is a regional Organization which 
consists of the National Standards Bodies of GCC member States. One of GSO 
main functions is to issue Gulf Standards /Technical regulations through 
specialized technical committees (TCs)  
GSO through the technical program of committee TC No4 " Metrology 
specification sector " has adopted the OIML  Standard No. R80-1:2010 " Rod 
and r ail tankers with ievel gauging .  Par 1: Metroligical and technical 
requirements " Issued by ( The International Organization of Legal Metrology ) 
which has been translated into Arabic. The Draft Standard has been prepared by 
(State of Qatar ). 
This standard h as been approved as a Gulf Standard without any technical 
modifications by GSO Board of Directors in its meeting No.( ),held on / / H , / / 
G. 
 
 Road and rail tankers with level gauging 
Part 1: Metrological and technical requirements
Camions et wagons citernes avec mesurage de niveau 
Partie 1: Exigences métrologiques et techniquesOIML R 80-1 Edition 2009 (E)OIML R 80-1
Edition 2009 (E)
ORGANISATION INTERNATIONALE
DEMÉTROLOGIE LÉGALE
INTERNATIONAL ORGANIZATION
OFLEGALMETROLOGY
INTERNATIONAL
RECOMMENDATION  
 
3 
 Contents 
 
 
Foreword  ..................................................................................................................... .............................  4 
1  Scope  ..................................................................................................................... .............................  5 
2  Terminology ................................................................................................................ .......................  5 
3  Classification and description.............................................................................................. ..............  14 
 3.1  General  ............................................................................................................................... .... 14 
 3.2  Construction of tanks ................................................................................................... ..........  15 
4  Units of measurement ....................................................................................................... ................  17 
5  Technical and metrological requirements .................................................................................... .....  17 
 5.1  General ................................................................................................................. ..................  17 
 5.2  Container of the measuring tank ......................................................................................... ...  20 
 5.3  Addition al devices ...................................................................................................... ...........  23 
 5.4  Level gauging system .................................................................................................... ........  25 
 5.5  Tank capacity table ..................................................................................................... ...........  28 
 5.6  Metrological requirements for indicating and ancill ary devices ............................................  29 
 5.7  Additional requirements for measur ing systems with electronics parts .................................  32 
6  Plates, documents and sealing .............................................................................................. ............  36 
 6.1  Identification plate .................................................................................................... .............  36 
 6.2  Measuring system document ............................................................................................... ..  36 
 6.3  Tank capacity plate on tanks with disp sticks scaled in non- volumetric units ........................  37 
 6.4  Verification certificate ................................................................................................ ...........  37 
 6.5  Seals ................................................................................................................... ....................  38 
7  Bibliography ............................................................................................................... ......................  40 
8  Index  ..................................................................................................................... ..........................  41 
Annex A Example for tankers with mech anical sensors (Informative) .......................................................  45 
Annex B Example for automatic meas uring systems with electronic le vel gauging (Informative) ............  54 
Annex C Examples for volume conversion – petrol eum products and lubrican ts (Informative) ................  58 
Annex D Examples for volume conversion - Liquefied petroleum gas (Informative) ................................  60 
Annex E Density and volume (of 1 kg) of  distilled water (Informative) ....................................................  61  
 
4 
 Foreword 
The International Organization of Legal Metrology (OIM L) is a worldwide, intergovernmental organization 
whose primary aim is to harmonize the regulations and metrological controls applied by the national 
metrological services, or related organizations, of its Me mber States. The main categories of OIML publications 
are: 
 International Recomme ndations (OIML R), which are model regulations that establish the 
metrological characteristics required of certain measuring instruments and which specify methods and 
equipment for checking their conformity. OI ML Member States shall implement these 
Recommendations to the greatest possible extent; 
 International Docu ments (OIML D), which are informative in nature and which are intended to 
harmonize and improve work in the field of legal metrology; 
 International Guides (OIML G), which are also informative in nature and which are intended to give 
guidelines for the application of certain requirements to legal metrology; and 
 International Basic P ublications (OIML B), which define the operating rules of the various OIML 
structures and systems. 
OIML Draft Recommendations, Documents and Guides are developed by Technical Committees or 
Subcommittees which comprise representatives from the Member States. Certain international and regional 
institutions also participate on a consultation basis. Co operative agreements have been established between the 
OIML and certain institutions, such as ISO and the IEC, with the objective of avoiding contradictory 
requirements. Consequently, manufacturers and users of measuring instruments, test laboratories, etc. may 
simultaneously apply OIML publications and those of other institutions. 
International Recommendations, Documents, Guides and Basic Publications are published in English (E) and 
translated into French (F) and ar e subject to periodic revision.  
Additionally, the OIML publishes or participates in the publication of Vocabularies (OIML V)  and periodically 
commissions legal metrology experts to write Expert Reports (OIML E) . Expert Reports are intended to 
provide information and advice, and are written solely  from the viewpoint of their author, without the 
involvement of a Technical Committee or Subcommittee, nor that of the CIML. Thus, they do not necessarily 
represent the views of the OIML. 
This publication - reference OIML R 80-1, edition 2009 (E) - was developed by the OIML Technical 
Subcommittee TC 8/SC 1 Static volume and mass measurement . It was approved for final publication by the 
International Committee of Legal Metrology in 2009 and will be submitted to the International Conference of 
Legal Metrology in 2012 for formal sanction. This Edition supersedes the previous edition of OIML R 80 
(Edition 1989).  
OIML Publications may be downloaded from the OIML  web site in the form of PDF files. Additional 
information on OIML Publications may be obtained from the Organization’s headquarters: 
Bureau International de Métrologie Légale 
11, rue Turgot - 75009 Paris - France Telephone: 33 (0)1 48 78 12 82 
Fax:  33 (0)1 42 82 17 27 
E-mail:  biml@oiml.org Internet:  www.oiml.org 
  
 
5 
 Road and rail tankers with level gauging 
Part 1: Metrological and technical requirements 
 
 1  SCOPE 
1.1 This Recommendation specifies the metrological and technical requirements applicable to 
static measuring systems for volume of liquids subject  to legal metrological controls. It also provides 
requirements for the approval of parts of the measuring systems. 
It applies to tankers for the transport of liquid produc ts by road and rail and used, in addition to their 
functions as carriers, as transportable measuring tanks. Examples are given in Annexes A and B. 
1.2 Tankers may be considered as measuring instrume nts for liquids of which the viscosity does 
not exceed 20 mPa.s at working temperature. 
1.3 This Recommendation is also applicable for m easuring partial volume received or delivered.  
1.4 Essential metrological requirements of this  Recommendation are in accordance with the 
relevant requirements of OIML R 117 Measuring systems for liquids other than water  [3] referring to 
measuring systems with liquid meters used for the same purpose. 
1.5 In addition to the metrological and technical requi rements included in this Part 1 (R 80-1) the 
methods of metrological controls and tests are given in Part 2 (R 80-2) and the test report formats in 
Part 3 (R 80-3). At the date of Part 1 publi cation , Part 2 and Part 3 are not available. 
1.6 This Recommendation does not include any aspects with respect to safety (see also 5.2.1). 
 
2  TERMINOLOGY 
The terminology used in this Recommendation conforms to the International Vocabulary of basic and 
general terms in metrology  [1] and the International Vocabulary of terms in legal metrology  [2]. In 
addition, for the purposes of this Recomme ndation, the following definitions apply. 
2.1 Transportable measuring tank 
Container , suitable for use as a volume measuring device for liquids, fixed on a truck (or on a railcar) 
or detachably connected to it, which may be s ubdivided into several measuring compartments.  
Note:   Hereafter referred to as measuring tank or tank.  
 
6 
 2.2 Static measuring system  
System that comprises a measuring tank, fitted w ith its ancillary and additional devices. Static 
measuring systems can also be utilized for measuring  the quantity of the liquid in the tank such as the 
volume at working conditions or at base conditions. 
Note:   Hereafter referred to as measuring system. 
2.3 Ancillary device 
Device intended to perform a particular function, directly involved in elaborating, transmitting or 
displaying measurement results. 
Examples of ancillary devices: 
 zero setting device; 
 repeating indicating device; 
 printing device; 
 memory device; 
 price indicating device; 
 conversion device. 
2.4 Additional device  
Part or device, other than an ancillary device, re quired to ensure correct measurement or intended to 
facilitate the measuring opera tions, or which could in any way affect the measurement. 
Examples of additional devices:  
 manifold; 
 sampling device; 
 gas indicator; 
 sight glass; 
 filter, pump; 
 gas elimination device; 
 device used for the transfer point; 
 anti-swirl device; 
 branches or bypasses; 
 valves, hoses. 
2.5 Electronic part 
Any device, component or measuring element containing electronics. 
2.6 Nominal capacity (of the tank or compartment) ( Vn) 
Volume indicated (marked) on the tank or its compartment.   
 
7 
 Notes: 1. The nominal capacity value usually corresponds to the volume of liquid which a tank or 
compartment contains at reference temperatur e when filled up to the maximum permissible 
level or volume mark.  
2. The nominal capacity value can be limited by safety regulations. 
2.7 Total capacity  
Maximum volume of liquid which a tank or compartm ent may contain up to overflowing, under rated 
operating conditions and at reference temperature. 
2.8 Expansion volume  
Difference between total and nominal capacity. 
2.9 True volume ( Vt) 
Conventional true value of volume of liquid in a tank or compartment at working temperature t.  
2.10 Indicated volume ( Vi) 
Value of volume provided by the volume measuring system. 
2.11 Error of indicated volume 
Difference between the indicated volume ( Vi) of the tank or compartment and the true volume ( Vt). 
2.12 Tank or compartment calibration (tank calibration) 
Set of operations to determine the capacity of a tank or compartment, using methods satisfying the 
technical and metrological requirements, such as measurement at one or several filling levels by 
means of geometric size measurement, gravimetric, or volumetric method. 
The gravimetric method determines the volume of liquid in the tank by means of weighing; the 
volumetric method determines the volume of liquid in the tank by means of measuring the volume of 
liquid entered in or emptied from the tank. 
2.13 Liquid level 
Level of the surface of the liquid, or the vapor/liquid interface in the tank. 
2.14 Reference point 
Point clearly identified on the vertical measurement axis, with reference to which the liquid level is 
measured. 
2.15 Reference point top (RPT) 
Reference point in the upper part of the tank, unde r normal operating conditions  above the liquid level.  
 
8 
 2.16 Reference point bottom (RPB) 
Reference point in the lower part of the tank,  under normal operating conditions below the liquid 
level. 
2.17 Reference height ( H) 
Distance, measured along the vertical measuremen t axis, between the reference point top and the 
reference point bottom. 
2.18 Ullage height ( C) 
Distance between the free surface of the liquid and the reference point top, measured along the vertical 
measurement axis. 
2.19 Liquid height ( h)  
Distance between the free surface of the liquid and the reference point botto m, measured along the 
vertical measurement axis. 
 
                    
   
Fig. 1 Schematic view of a tank to determine 2.15 – 2.19 
 
2.20 Sensitivity of a tank 
Change in the level of liquid ∆h divided by the corresponding relative change in volume ∆V/V for the 
contained volume V at the level h. 
 
 
9 
 2.21 Tank capacity table 
Table which shows the relation between the liqui d level and the volume contained in the tank 
(compartment) at that level under reference conditions (including the position of the tank). 
2.22 Baffle 
Internal device of the tank or compartment, e.g. a partition wall or obstacle inside the tank, intended to 
damp the movement of liquid during transport and to increase the mechanical  stability of the tank. 
2.23 Level sensor 
Measuring device for the level of a liquid in a tank or compartment.  
2.24 Measuring range of the level sensor 
Range between the minimum and maximum possible indi cations of the level sensor. The lower limit is 
type and system dependent and shall be significan tly less than the liquid level corresponding to the 
minimum measured quantity of the tank or compartm ent. The upper limit depends on the tank height 
and shall be above the maximum permissible filling height of the tank or compartment. 
2.25 Temperature sensor 
Measuring device for the temperature of the liquid. 
2.26 Inclination sensor 
Measuring device for the pitch and roll angles. 
2.27 Longitudinal axis and pitch angle 
Symmetry axis of the tank parallel to the main dir ection of travel, when the tank is in normal position. 
The vertical angle by which this axis is rotated is  referred to as the pitch angle. It is positive if the 
front part of the tank is lifted.  
2.28 Transverse axis and roll angle 
Horizontal axis of the tank perpendicular to the longitudinal axis, when the tank is in its normal 
position. The vertical angle by which this axis is rotate d is referred to as the roll angle. It is positive if 
the right part of the tank (in relation to the direction of travel) is lifted. 
2.29 Damping tube 
Mechanical device (usually in the form of a tube  with holes) intended to minimize or eliminate the 
effect of surface waves on the level measurement an d to protect the level sensor against mechanical 
damage. 
2.30 Transfer point 
Point at which the liquid is defined as being delivered or received.  
 
10 
 2.31 Empty hose (Dry hose) 
Hose and/or pipework containing liquid produc ts only during a transaction and usually being 
completely evacuated before the transaction is termin ated. It is connected downstream of the transfer 
point (the transfer point is located upstream of the delivery hose or downstream of the receiving hose). 
2.32 Full hose (Wet hose) 
Hose and/or pipework filled with  liquid product prior to and after a transaction. In this case the 
transfer point is located close to the outlet of the full hose (the transfer point consists of a closing 
device located in the delivery or receiving line). 
2.33 Collector (Manifold) 
Collecting line connected via valves to the outle ts of the measuring compartments and allowing 
delivery from any one or several compartments via common pipework. 
2.34 Built-in manifold 
Collecting line connected via diverting valves to th e discharge pipes of the measuring compartments 
and allowing delivery from any one or several co mpartments via a common pipework. A compartment 
connected to a built-in manifold has two possible outlets: its own outlet valv e and its own diverting 
valve. 
2.35 Direct discharger 
Tanker discharged by gravity, each individual measuring compartment having its own outlet. 
Frequently, the loading adap ter is used as the outlet. 
2.36 Top loading 
Loading of a measuring compartment from the top th rough the fill hole cover opened for this purpose. 
2.37 Bottom loading 
Loading of a measuring compartment from the bottom through a standardized dry adapter (e.g. an API 
adapter) and the bottom valve that is integrated into the bottom of the measuring compartment and 
opened for this purpose. 
2.38 Transaction 
Delivery of liquid products from one or several  measuring compartments to a recipient.  
Note:  The transaction can also be a receipt (e.g. a milk collecting truck). A transaction is settled 
when the parties interested in the transaction have made their agreement known (explicitly or 
implicitly) as regards the amount of the transaction. This may be a payment, signing a credit 
card voucher, signing a delivery order, etc. 
The parties interested in a transaction may be  the parties themselves or their representatives 
(for example: the employee in a filling station, the driver of a tanker).  
 
11 
 2.39 Reference position 
Position for the discharge (or loadin g) of the measuring tank in accordan ce with the design drawing. It 
is the basis for the inclination correction function. The zero point of the inclination represents the zero 
point for both (longitudinal and transversal) inclinations.  
2.40 Working conditions  
Conditions under which the volume of liquid is to be measured, at th e point of measurement (example: 
temperature, viscosity, position of the tank). 
2.41 Base conditions 
Specified conditions under which the measured volume of liquid is converted (example: temperature, 
density, pressure). 
2.42 Liquid detector 
Device intended to detect the presence of liquid in th e pipework or the tank and to check, before start-
up and after stopping, that all or part of the measuri ng system is either filled completely with liquid 
(full hose measuring systems) or completely empty of liquid (empty hose measuring system).  
Note: A liquid detector may also be used for high level detection.  
2.43 Liquid indicator 
Device to indicate the presence of liqui d in the pipework (e.g. sight glass). 
2.44 Minimum measured quantity MMQ ( Vmin) 
Smallest volume of liquid for which the measureme nt is metrologically acceptable for the tank or 
individually for each of its compartments. It shall be  specified only for measuri ng systems suitable for 
measuring partial volumes. 
Alternatively, the terms “minimum deliver y” or “minimum receipt” may be used. 
2.45 Minimum specified volume deviation ( Emin) 
Twice the absolute value of the maximum permissi ble error for the minimum measured quantity of a 
tank or compartment. 
2.46 Influence quantity 
Quantity which is not the object of the measuremen t but which influences the value of the measurand 
or the indication of the tank. 
2.47 Disturbance 
Influence quantity whose value lies within the limits defined by the relevant requirements, but outside 
the established rated operating conditions for the tank.  
 
12 
 2.48 Fault 
Difference between the error of indication and the intrinsic error of a measuring instrument. 
Notes: 1. Principally, a fault is the result of an und esired change of data contained in or flowing 
through an electronic measuring instrument. 
2. From the definition it follows that in this Recommendation, a "fault" is a numerical value 
which is expressed either in a unit of measureme nt or as a relative value, for instance in %.  
2.49 Significant fault  
Fault greater than the value specified in 5.7.1.4. 
2.50 Rated operating conditions  
Conditions of use giving the range of values of  influence quantities for which the specified 
metrological characteristics of a measuring instru ment are intended to lie within given limits. 
2.51 Reference conditions  
Conditions of use prescribed for testing the perfo rmance of a measuring instrument or for inter-
comparison of results of measurements. 
Note: The reference conditions generally include re ference values or reference ranges for the 
influence quantities affecting the measuring instrument. 
2.52 Influence factor 
Influence quantity having a value within the ra ted operating conditions specified in 5.1.1. 
2.53 Durability 
Ability of a measuring instrument to maintain its  performance characteristics over a period of use. 
2.54 Intrinsic error 
Error (of the indicated volume) of a measur ing system used under reference conditions. 
2.55 Initial intrinsic error  
Intrinsic error as determined pr ior to each performance tests. 
2.56 Checking facility  
Facility that is incorporated in a measuring inst rument and which enables significant faults to be 
detected and acted upon. 
Note:  "Acted upon" refers to any adequate response by the measuring instrument (luminous signal, 
acoustic signal, prevention of the measurement process, etc.).  
 
13 
 2.57 Automatic checking facility 
Checking facility that operates without  the intervention of an operator. 
2.58 Permanent automatic checking facility (type P) 
Automatic checking facility that operates at each measurement cycle. 
2.59 Intermittent automatic checking facility (type I) 
Automatic checking facility that operates at certain time intervals or per fixed number of measurement 
cycles. 
2.60 Symbols and abbreviations 
Vn nominal capacity (of the tank or compartment) 
Vt total volume at working conditions 
Vi indicated volume 
H reference height 
C ullage height 
h liquid height 
Vmin minimum measured quantity 
Emin minimum specified volume deviation 
Ux expanded uncertainty of level measurement 
∆Vt,i  partial volume at working temperature t 
t  working temperature 
t0 base temperature 
∆V0,i partial volume at base conditions 
V0 total volume at base conditions 
φ(Vt,t) conversion function 
α0 thermal expansion coefficient 
ρ0 density at base conditions 
RPT reference point top RPB reference point bottom 
MMQ minimum measured quantity 
  
 
14 
 3 CLASSIFICATION AND DESCRIPTIONS 
3.1 General  
3.1.1 Determination of the quantity in a road tanker or rail car involves:  
 the method of measurement to derive the volume; 
 ancillary devices; 
 operating conditions (influence factors); 
 tank capacity and its calibration table; 
 the method of mounting of the tank. 
3.1.2 Measurement methods: 
 level measurement:  
- by a manual or visual (mechanical) level gauge, or an electronic level gauge; 
 temperature measurement:  
- in the case of the measurement of a volume transferred (delivered/received), by an 
electrical temperature sensor located on the discharge/inlet line (pipe); or  
- in the case of inventory measurement, by one or more temperature sensors/thermometers 
located in such a way that th ey allow the mean temperature of the liquid volume in the 
tank or in each compartment to be determined, respectively;  
 volume measurement at working or base cond itions (delivered/received including partial 
deliveries): 
- by an electronic computing device or controller, or by manual calculation using data from 
the tank calibration table and the volume correction table. 
The manual or visual gauging method may be based on: 
 a single or more volumetric marks; 
 a graduated window in the dome; 
 another measuring device with a graduated scale (with a viewing window or an external gauge 
tube or with any means of transferring the level position outside the tank); 
 a dipstick or a dip tape. 
Electronic level gauging method may be based on: 
 floats/displacers with electronic det ection (magnetic or magneto-strictive); 
 ultrasonic level gauge; 
 radar (microwave) level gauge; 
 other non-contact level gauges such as electrical capacitance. 
Automatic volume measurements are achieved by the electronic computing device or controller, and 
characterized by automatic volume determination.  
 
15 
 Note:   This may include:  
 complete automatic control and supe rvision of the deliveries/receipts; 
 automatic taking into account of the influence of inclination, stage of emptying and/or waves. 
3.1.3 Regarding the kind of delivery/receipt that the tank may be designed for: 
 delivery/receipt of full compartment only; 
 delivery/receipt of partial volume of a compartment; 
 automatic measurement of the average temp erature of the delivered/received volume; 
 automatic volume conversion. 
3.1.4 For the ancillary devices, tanks may be fitted with or without:  
 installations for measuring partial volumes received or delivered; 
 internal pumps; 
 collectors; 
 full hose installations.  
3.1.5 The main influence factors that can have a major effect during calibration and use of tankers 
are pressure and temperature. 
(a) regarding the pressure, the tanks may be: 
- at atmospheric pressure; 
- under pressure (e.g. for liquefied gases or beer). 
(b) regarding the temperature, the tanks may be: 
- without means for heating and with or without thermal insulation of the contents; 
- with means for heating and with or without thermal insulation of the contents. 
3.1.6 Regarding the capacity of the tank, road tankers are usually between 0.5 m3 and 50 m3 and rail 
tankers between 10 m3 and 120 m3. 
3.1.7 Regarding the method of mounting,  the tanks of road tankers may be: 
 mounted directly and permanently on the chassis of a vehicle, trailer, or semi-articulated 
trailer, or be self-propelled, detachable; 
 mounted temporarily on the vehicle by means of  devices that ensure that the position of the 
tank when mounted on the vehicle remains unchanged. 
3.2 Construction of tanks 
3.2.1 If a tank is divided into compartments, each sh all be considered as a separate tank and shall be 
subject to the requirements of this Recommendation.   
 
16 
 3.2.2 Each tank shall comprise a shell and ends and discharge devices. 
3.2.3 The shape and the mounting of the tank as well as the installation of the discharge device shall 
be such that the tank drains completely. 
3.2.4 The discharge device shall comprise one or two discharge pipe(s) (allowing offloading on 
either side of the tanker), each equipped with a st op valve. The flow of liquid between the tank and the 
discharge pipe(s) may be stopped by a foot valve.  
If the tank is equipped with two discharge pipes, su itable interlock facilities shall prevent the use of 
both discharge pipes together. 
If necessary, a tank may incorporate devices fitted at the lowest point for water separation. 
Note:   A tank may be equipped with a third dischar ge pipe (on its rear side) fulfilling all the 
requirements of 3.2.4. 
3.2.5 Tanks fitted with level gauges 
Tanks fitted with level gauges shall comprise: 3.2.5.1 A dome with reinforcing elements servi ng as a manhole and as an expansion space and in 
some (non-fuel) applications to incr ease the sensitivity of the tank. It is located on the top of the tank. 
The dome may incorporate the following: 
 a filling aperture, fitted with a leak-proof cover; 
 an orifice to observe the filling; 
 a venting device or double-acting safety valve. 
The level index may be in the dome or in the uppe r part of the shell, provided that the sensitivity 
requirements are met. 
3.2.5.2 For tanks fitted with mechanical level gaug es, a ladder shall be installed giving access to the 
dome and the platform, thus allowing the operator to  perform the measurement or to check the tank. 
3.2.5.3 For tanks fitted with electronic level gauging: 
 access to the interior of the tank shall either be prevented by sealing or other means; or 
 a visual checking of the interior shall easily be possible according to 3.2.5.2 (for instance in 
the case of top loading). 
3.2.6 Tankers for liquefied gases shall not have domes and are subject to regulations covering the 
construction of pressure vessels. 
3.2.7 Where appropriate, tanks shall be fitte d with breather valves and flame arresters. 
3.2.8 Examples for tankers with mechanical and electronic level gauging are given in informative 
Annexes A and B.  
 
17 
 4 UNITS OF MEASUREMENT 
The authorized units of measurement are those of th e International System of Units (SI). Lengths shall 
be given in mm, volumes in litres. 
If units of measurement other than those of the SI are authorized by the state, these legal units of 
measurement may be used. In international trade, the officially agreed e quivalences between these 
units of measurement and those of the SI shall be applied. 
 
5 TECHNICAL AND METROLOGICAL REQUIREMENTS 
5.1 General  
5.1.1 Rated operating conditions 
Measuring systems according to this Recommendation shall be designed and manufactured such that 
their errors do not exceed the maximum permissible errors given in Table 2 under the following rated 
operating conditions: 
Rated operating conditions 
low – 25 °C (1) 
a) Environmental temperature 
high + 55 °C (1) 
b) Humidity Up to condensing 
c) Vibration less than 10 Hz – 150 Hz, 7 ms-2, 1 m2s-3,  
–3 dB/octave   
d) AC mains voltage (2), (3) Unom – 15 % to Unom + 10 % 
e) AC mains frequency (2) fnom – 2 % to fnom + 2 % 
f) Voltage of internal battery (2) The lowest voltage at which the instrument functions 
properly according to the sp ecifications up to the 
voltage of a new battery. 
12 V battery  9 V – 16 V 
g) Voltage of a road vehicle battery (2) 
24 V battery 16 V – 32 V 
h) Inclination To be specified by the manufacturer 
(1) This value is to be decided by the national authority as it depends on the climatic conditions and the 
expected conditions of application (indoors, outdoors,  etc.) that are different in different countries. 
(2) Whatever is applicable. 
(3) The values of Unom are those marked on th e measuring instrument. 
 In case a range is specified, the “– 15 %” relates to  the lowest value and the “+ 10 %” to the highest 
value of the range. 
  
 
18 
 5.1.2 Accuracy classification and maximum permissible errors 
Depending on the field of application the static me asuring systems mounted on the road or rail tankers 
are classified into four accuracy classes ac cording to Table 1. The corresponding maximum 
permissible errors on quantity indications are specified in Table 2. 
 
Table 1 Accuracy classes depending on the field of application 
Accuracy class Type of measuring system 
0.5  Measuring systems for liquids of which the viscosity does not 
exceed 20 mPa ⋅s at working temperature; 
 Measuring systems for milk, beer, and other foaming liquids; 
 Measuring systems for refueling aircraft. 
1.0  Measuring systems for liquefied gases under pressure 
measured at a temperature equal or above –10 °C. 
1. 5  Measuring systems for liquefied carbon dioxide; 
 Measuring systems for liquefied gases under pressure 
measured at a temperature below –10 °C. 
2.5  Measuring systems for cryogenic liquids. 
 
Table 2 Accuracy classes and maximum permissible errors 
Accuracy class  
0.5 1.0 1.5 2.5 
Static measuring system (A) 0.5 % 1.0 % 1.5 % 2.5 % 
Transportable measuring 
tank (B) 0.3 % 0.5 % 1.0 % 1.5 % 
 
5.1.3 Conditions for applying maximum permissible error 5.1.3.1 Maximum permissible errors in line A of Table 2 apply to complete measuring systems, under 
rated operating conditions, without any adjust ment between the various tests, for: 
 type approval; 
 initial verification; 
 subsequent verifications. 
5.1.3.2 Maximum permissible errors in line B of Table 2 apply to: 
 type approval of a measuring tank, un der rated operating conditions; and  
 verification of the tank as a preliminary stage of the initial verification of the measuring 
system.  
 
19 
 5.1.3.3 For measured volumes greater than the mini mum measured quantity up to twice the minimum 
measured quantity, the absolute value of the maximum permissible error shall not be less than  Emin. 
5.1.4 Base conditions 
Recommended base temperature is 15 °C. Other base temperatures such as 20 °C and 27 °C may be 
used if established by the national metrology body in the country. R ecommended base pressure is 
normal atmospheric pressure (0.1 Mpa).  
The use of other values for justified reasons is allowed. 
5.1.5 Requirements on temperature measurement 
5.1.5.1 For the purpose of volume conversion, the maximum permissible error for the determination 
of the temperature is ± 1 °C for accuracy class 2.5 and ± 0.5 °C for other accuracy classes. 
Note : These maximum permissible errors apply to the indication by the corresponding calculator 
with its indicating device and include the errors  due to rounding if using digital inputs.  
5.1.5.2 For the measurement of a volume transferred (received or discharged), the temperature 
element (sensor) shall be installed in the inlet/di scharge line beneath the tank at a location where under 
all discharge or loading modes the liquid flow passes by the sensor. In the case of separate liquid 
paths, additional sensor(s) shall be installed. 
5.1.5.3 If the road or rail tanker is used for st atic volume measurement of the inventory, the 
temperature sensor(s) shall be installed inside the ta nk/each compartment in such  a way that they give 
the mean temperature of the liquid volume in the tank/compartment in accordance with the 
requirements of 5.1.5.1. 
5.1.5.4 The measuring system shall allow the read- out of the actual temperature value. A permanent 
indication is not necessary. 
5.1.6 Nominal capacity 
Nominal capacity of a measuring tank or of its compartment shall be at least 500 L unless stated 
otherwise in the type approval certificate. 
5.1.7 Minimum measured quantity 
5.1.7.1 The minimum measured quantity shall be sp ecified for each compartment of a tank and shall 
not exceed a quarter (1/4) of its nominal capacity.  
5.1.7.2 The minimum measured quantity shall be equa l to or greater than the larger of the two 
following values: 
 the volume corresponding to the level difference given in Table 3, according to the accuracy 
class and with the smallest sensitivity;  
 
20 
  the volume which corresponds to the manufactur ing tolerance on the volume (differences 
between the actual tank geometry and the design specifications) and which does not exceed three-fifths (3/5) of the maximum permissible error specified in line A of Table 2 for each 
permitted inclination. 
Table 3 Minimum level difference corresponding to MMQ ( Vmin) 
Accuracy class  
0.5 1.0 1.5 2.5 
Level difference 200 mm 171 mm 190 mm 200 mm 
Note : The given level differences are based on an expanded uncertainty Ux for the corresponding 
accuracy classes given in 5.4.3.1 Table 6.  
5.1.7.3 The minimum measured quantity of a measuri ng system shall be given by one of the following 
forms: 
 1 × 10n, 2 × 10n or 5 × 10n litres, where n is a whole number; 
 entire multiples of 100 litres. 
5.2 Container of the measuring tank 
5.2.1 Safety and other non-metrological requirements 
5.2.1.1 National and international organizations, o fficial services concerned with the transport of 
dangerous goods, and authorities r esponsible for the supervision of  the production of pressured vessels 
lay down conditions for the construction of road and rail tankers intended for the transport of liquids 
contained in tanks, without overload and free from da nger. Additional regulations for safety at work 
and protection against fire and explosion ma y exist. These conditions shall be observed. 
5.2.1.2 In the case of tankers for potable liquids, the structural characteristics of the tank (shape, 
material, etc.) shall have no adverse effect on the qu ality of the liquid transported; the advice of the 
health authorities in this regard shall be sought. 
The application of the above-mentioned requirement s shall be compatible with the measuring function 
of the tank. 
5.2.1.3 The specification of the nominal capacity sha ll take into account the national or international 
regulations prescribing the maxi mum filling volume of tanks. 
5.2.2 General requirements on the construction of the container 
5.2.2.1 Shapes, materials, reinforc ing elements and methods of shaping or assembly shall be chosen 
so that the containers are sufficiently unaffected by  atmospheric agents and the liquids they contain, 
and are practically not subject to di stortion under rated operating conditions. 
5.2.2.2 The container shall be tight. Proof by the safety tests carried out is generally sufficient.   
 
21 
 5.2.2.3 The reference height H of a tank or each compartment shall not vary during filling more than 
the greater of the two values given in Table 4. 
Table 4 Maximum permissible variation of the reference height in dependence of the accuracy class  
Accuracy class  
0.5 1.0 1.5 2.5 
Maximum permissible variation 
of the reference height H (mm) 2 mm or 
H/1000 4 mm or H/500 
 
5.2.2.4 The capacity of a compartment shall not cha nge by more than one-third (1/3) of the maximum 
permissible error specified in line B of Table 2 when the neighboring compartment or compartments 
are filled or emptied. 
5.2.2.5 The material of the tank shall be chosen so that the capacity of the tank shall not change more 
than one-third (1/3) of the maximum permissible error specified in line B of Table 2 when the 
temperature of the tank changes in the range of ± 10 °C from the reference temperature. 
Note:  This condition is fulfilled if th e linear expansion coefficient of the tank material is less than 
33·10-6 K-1. 
5.2.2.6 Tanks for liquids which are not measured at atmospheric pressure shall be designed in such a 
way that their capacity in the whole admissible pr essure range does not change more than one-fifth 
(1/5) of the maximum permissible error specified in line B of Table 2. 
5.2.2.7 Every tank or compartment shall be of such  a shape that no air is trapped during the filling and 
no liquid is retained during the emptying in an y admissible position of use of the equipment. 
5.2.2.8 Spouts, mouldings or vent pipes and valves ma y be utilized in order to comply with the above 
requirements. 
5.2.2.9 The complete drainage shall be ensured: 
 by an adequate shape of the tank; 
 by a slope of at least 2 % (1.2°) of the tank bottom with the vehicle on horizontal ground; or  
 by other means. 
All road measuring tanks shall be designed to dischar ge within an inclination of at least ± 2 % of the 
reference position. 
If complete drainage is not possible in all positions that may be expected during use, 
monitoring/indicating facilities shall be provided to  ensure complete emptying (for example, by 
additional liquid sensors in the compartm ent, or by monitoring the inclination).  
 
22 
 5.2.2.10 The volume of liquid remaining in the tank or compartment after its complete draining 
shall not be greater than one-tenth (1/10) of th e absolute value of the maximum permissible error 
given in line B of Table 2 applied to the capacity  of the tank or compartment. This volume may 
remain in the tank for reasons of conditions of constr uction or mounting (for example, at the joints).  
5.2.2.11 Baffles and reinforcing elements that may be fitted in the tank shall have a shape and shall 
be provided with appropriate orifices such that filli ng, draining and checking the emptiness of the tank 
are not impeded. 
5.2.2.12 The introduction of dead wood inside the tank for the purpose of adjusting the capacity to 
a given value, or any other body which when remo ved or changed could modify the capacity of the 
tanks, is prohibited.  
5.2.2.13 Fixed internal elements in the measuri ng compartments (e.g. heating coils) are permitted 
if they have been present during the calibra tion and cannot be modified or dismounted.  
5.2.2.14 The tank or compartment geometry shoul d be such that waves at the liquid surface are 
adequately damped. 
5.2.2.15 To minimize inclination effects, the measuring tanks should be symmetrical both in the 
longitudinal and in the transverse direction and the level sensors should be installed centrally. Other 
constructions are permitted if correct  volume measurement is ensured. 
5.2.2.16 If correct measurement is not possible under all inclinations, which may be expected 
during use, the tank shall be equipped with a device th at indicates the actual inclination with respect to 
the range of inclinations required for a correct measurement. 
5.2.2.17 The interior of the measuring tank shall be accessible for inspection purposes via a 
manhole, provided that safety or other regulations do not exclude this. In conformity with 3.2.5.3 it shall be sealed to prevent manipulations. 
5.2.2.18 The capacity of a measuring tank shall not  deviate by more than 10 % from that specified 
in the design documents. 
5.2.2.19 The dome, when fitted, shall be on the uppe r part of the body and shall be welded to the 
latter. In general, the mechanical leve l gauging device shall be inside the dome. 
5.2.2.20 The dome may have a cylindrical or paralle lepipedic form, with vertical side-walls. If the 
dome is parallelepipedic in form it may be of the same length as the tank itself. 
5.2.2.21 If the sidewalls of the dome are mounted so  that they penetrate the tank shell, in such a 
way that air pockets could form when filling at the maximum permitted filling level, orifices or cut-
outs of appropriate dimensions and at high enough po sitions to avoid such pockets shall be provided.  
 
23 
 5.2.2.22 The transverse section of the shell and dome shall have a vertical axis of symmetry. Other 
constructions are permitted if correct  volume measurement is ensured. 
5.2.2.23 The dimensions of the horizontal section of the dome shall be such as to allow inspection 
of the interior of the tank. A diameter of at least 500 mm is recommended. 
5.3 Additional devices 
5.3.1 Discharge device 
5.3.1.1 The discharge device shall ensure complete and rapid discharge of the liquid contained in the 
tank. For this purpose, the discharge device shall be connected to the lowest part of the tank shell. 
5.3.1.2 For tanks of special construction dedicated to  airports, the fitting of a device to collect water 
and impurities precipitated by a liquid contained in the tank is permitted. This device shall have a 
separate drain pipe, of small diameter, when the norma l discharge pipe is not connected to the lowest 
part of the tank. 
The collecting device may be mounted: 
 over the whole of the lower part of the tank; or 
 over a reduced area of the lower part. 
5.3.1.3 The discharge pipe shall be as short as possi ble and have an adequate slope towards the stop 
valve. A resulting slope of at least 2° is recommended. 
5.3.1.4 Each compartment shall have means fo r being discharged independently. A discharge 
manifold is permitted under the following conditions: 
Manifolds should have suitable control facilities th at prevent the flowing back from one compartment 
to another or provide evidence of such a situation. 
However, when the conditions of exploitation rende r it necessary, the legal metrology authority may 
accept the use of non secured manifolds provided that appropriate information is easily legible and 
readable close to the delivering points. 
This information may consist of a label provi ding one of the following appropriate texts: 
 “The presence of the collector is not allowe d during the delivery from the measuring tank”, 
when the collector is easily removable; 
 “Check the liquid level before and after each delivery from a compartment”, when it may be 
acceptable that the collector is not easily removable. 
5.3.1.5 The existence of a manifold shall be  indicated in the verification certificate. 
5.3.1.6 Stop valves shall be readily accessible and shall be  at the rear or on the appropriate side of the 
tank.  
 
24 
 5.3.1.7 If a tank consists of more than one measuring compartment, each compartment shall be 
provided with a separate (manual or automatic) shutoff device in each delivery line. Unwanted 
mixtures of the products from different compartments  shall be prevented by constructive or control 
devices. 
5.3.1.8 In the vicinity of the lowest point of  each delivery line, liquid detectors or sight glasses 
(excepted for automatic measuring systems) shall be  installed, if necessary, for checking emptiness. 
5.3.1.9 Pipework, whose filling quantity has an effect  on the measurement result, shall not be flexible 
and shall be rigidly laid.  
5.3.1.10 For full hose delivery, it shall be ensured by a separate gas separator, or an equivalent 
function of existing parts, that the full hose is completely filled at the time of level gauging. 
5.3.1.11 Control lines and control devices whose manipulation might falsify the measurement result 
shall be protected against tampering. 
5.3.1.12 During a transaction, the change from full to empty hose and vice versa as well as the 
change between the full hose systems are admissible only when the filling levels are monitored in all 
measuring compartments so that manipulations are evident. 
5.3.1.13 Venting devices on the measuring system  shall be protected against dismounting and 
removal as well as against manipulations from the outside. 
5.3.1.14 The measuring tank shall have supports in th e longitudinal and in the transverse directions. 
Their length shall be greater than 500 mm to acco mmodate an electronic water-level to mark the 
reference plane for the normal position of the measuring tank. 
5.3.2 Installations for external measurement and pumping  
5.3.2.1 If it is intended to connect the tank to separate pumping or measuring devices, it should be 
provided with the appropriate detachable coupling de vices which shall be as short as possible and easy 
to connect and disconnect. 
5.3.2.2  Pumping installations shall comprise, in a ddition to the pump itself, no more than one filter 
and very short pipes (no valves or branch connections ). The installation shall be constructed so that it 
can be drained completely, each time the tank is emptied, without the need for any special measures. 
5.3.2.3  For tanks equipped with a built-in mani fold for measuring partial volumes delivered, the 
fitting of a diverting valve on each disch arge pipe is permitted provided that: 
 any leakage of liquid through the diverting valve can be detected (for example: the built-in 
manifold ensures complete and rapid discharge of the liquid that it contains. A sight glass or monitoring device at its bottom end shall allow the checking of its emptiness); and  
 
25 
  the installation and the control of the diverting valves is such that the product cannot flow 
back from one compartment to another. 
5.3.2.4 Sampling device 
The measuring system may include a sampling devi ce intended to determine the properties of the 
liquid to be measured. 
Obtaining a representative sample is us ually needed for the following reasons:  
 to calculate the standard volume (i.e. volume at defined base conditions); 
 to determine the density of the liquid for conversion; 
 to determine if the liquid transferred is with in the quality specification, and its properties. 
The quantity of a sample taken from the tank does not need to be accounted for if the quantity of the 
sample is less than one-third (1/3) of the absolu te value of the maximum permissible error given in 
line B of Table 2 applied to the capacity of the tank or compartment. 
5.3.2.5 Additivation systems 
The measuring system may include an injection devi ce that injects additives to the delivered product. 
If the additivation ratio is not higher than 1:500 th ere is no need to measur e the additive quantity. 
5.3.3 Other devices 
5.3.3.1 Tank may be fitted with: 
  level switch; 
  level detectors; 
  high level shutoff devices; 
  etc. 
5.3.3.2 The use of devices to facilitate reading of the index, or to stop the flow automatically when the 
level of the liquid reaches the index, are permitted, provided that no additional measurement errors are 
introduced. 
5.4 Level gauging system  
5.4.1 General requirements 5.4.1.1 The level gauging device shall ensure a sa fe, easy and unambiguous readout, practically 
independent of tank tilt under rated operating conditions. 
5.4.1.2 The index (e.g. volumetric marks, scales), or  the vertical measurement axis, shall be as near as 
possible to the center of the horizontal sections of the tank. 
5.4.1.3 The level gauging system shall perform a valid height measurement only when the liquid 
surface has calmed down so that the result is reproducible.   
 
26 
 5.4.1.4 When the measuring range of the level sensor is reached, a visual and/or audible indication 
shall automatically occur. 
5.4.2 Requirements on level gauging for full compartment delivery 
5.4.2.1 The shape of the tank shall be such that, in the zone where the levels are gauged, a sensitivity 
equal to or greater than the values given in Table 5 is attained. 
Table 5 Sensitivity of the tank depending on the accuracy class of the measuring system  
for full compartment delivery 
Accuracy classes   
0.5  1.0  1.5 2.5 
Minimum sensitivity of tank ∆h per ∆V/V in mm / ‰ 
(i.e. in mm for 1/1000 of measured volume) 1.5 1.0 0.5 0.3 
 
5.4.2.2 For non-pressurized tanks, it shall be possibl e to gauge the level of the contained liquid 
manually. The gauging device shall be positioned as close as possible to the curve connecting the 
centers of gravity of the horizontal cross sections  of the compartment in the level measuring range. 
When the lower end of the gauging device is close to the bottom of the tank, its axis should intersect 
the lower tank bottom at a point having no orifice or  obstacle within a radius of 100 mm. If this is not 
the case, there shall be a horizontal and non rem ovable plate of 100 mm × 100 mm in order to ensure 
repeatability of measurements. 
5.4.2.3 The reference points RPB and RPT shall be clearly defined and realized. 
5.4.2.4 The joint between the shell and the dome shall be such that the gauging device can be held in a 
vertical position during measurement. 
5.4.3 Requirements on level gauging for partial delivery 
5.4.3.1 The expanded uncertainty of the level me asurement shall not exceed the values given in 
Table 6. 
Table 6 Level measurement uncertainty for partial delivery 
Accuracy classes  
0.5 1.0 1.5 2.5 
Level measurement 
uncertainty Ux in mm 0.7 1.2 2 3.5 
 
The expanded uncertainty of measurement, Ux, is stated in accordance with the Guide to the 
expression of uncertainty in measurement  (GUM) [4] as the standard uncertainty of measurement  
 
27 
 multiplied by the coverage factor k=2 which for a normal distribution corresponds to a coverage 
probability of approximately 95 %. 
Other values of expanded uncertainties Ux may be fixed in the type approval certificate of the 
measuring system. 
5.4.3.2 The resolution of the level indication sha ll be in accordance with the values in Table 7. 
Table 7 Resolution of the level indication 
Accuracy classes  
0.5 1.0 1.5 2.5 
Maximum value of the 
resolution for the level 
indication in mm 0.1 0.2 0.5 1.0 
 
5.4.3.3 To dampen the surface waves,  the level sensor may be fitted in a damping tube. In the area of 
the tank bottom, of the tank roof and in-between, th is tube shall be provided with openings for liquid 
exchange. The tube shall not affect the measure ment (e.g. dirt or sedimentation occurring under 
regular operation). 
5.4.4 Specific requirements for level gauging systems with float 
5.4.4.1 The float shall not change its mass and volum e due to the influence of the product measured. 
Neither pressure shall lead to a change in its volume.  
5.4.4.2 The cross-section of float in the range of immersion depth change shall be well known. 
5.4.4.3 The shape of the float shall be designed so that it does not retain liquid except the liquid layer 
caused by capillary effects. Additionally, no gas or  air cushion shall be formed under the float. 
5.4.4.4 Within the permissible density range of th e measured liquid at base conditions, the immersion 
depth of the float shall not change by more than the value given in Table 8. The permissible density 
range shall be specified in the type approval cer tificate. For measuring systems not fitted with the 
corresponding correction, the influence on the immersi on depth that results from variation in the liquid 
density should be included in the uncertain ty evaluation of the level measurement. 
Table 8 Change of float immersion depth 
Accuracy classes Maximal change of immersion depth 
in mm for 
0.5 1.0 1.5 2.5 
- partial deliveries 0.5  0.8  1.6 2.5 
- full compartment deliveries 1.5 2.4 4.8 7.5 
  
 
28 
 5.4.5 Specific requirements for level gauging systems based on the ultrasound transit time 
measurements 
5.4.5.1 Within the permissible product parameters range (mainly density and modulus of elasticity), 
the measured height shall not change by more than the values given in Table 6. The permissible ranges 
of product parameters shall be specified in the type approval certificate. 
5.4.5.2 The effects of the product parameters on the transit time of the ultrasound signal may be 
compensated by suitable methods (e.g. by reference marks). 
5.5 Tank capacity table 
5.5.1 For the conversion of the result of the level gauging into volume, the electronic data 
processing system shall store a tank capacity table with pairs of level/volume values for each measuring compartment. The number and distance of  these value pairs are selected according to the 
real tank geometry. Intermediate values are calculate d by suitable interpolation. Extrapolation is not 
admissible.  
5.5.2 The tank capacity table shall be determined  for each compartment of the measuring tank by 
volumetric, gravimetric or geometric methods. 
Note:   A calculation of the tank capacity table onl y based on the construction documents is not 
permitted. 
5.5.3 The level range of the tank capacity tabl e shall encompass all filling states occurring in 
practical operation. Filling of a measuring compartment to a level beyond the maximum permissible point of the tank capacity table shall be prevented or  shall be detected by means and a visual and/or 
audible indication shall occur. 
5.5.4 Volume effects of the inclination in the ra nge specified for a given system (pitch and roll 
angles) shall not exceed the minimum specified vol ume deviation for partial delivery or the value 
given in line B of Table 2 of nominal compartment volume for full compartment delivery. 
5.5.5 If compliance with the requirements of 5.1.5.2 and 5.1.5.3, respectively, requires that a 
correction for inclination should be made, the inclined position of the measuring tank shall be 
measured during level detection usin g inclination sensors rigidly fixed to the tank. The inclination data 
are utilized to correct the measure ment using a suitable algorithm. 
5.5.6 The tank capacity table compiled during the calibration as well as the inclination correction 
data, when relevant, shall be stored in the syst em so that they are protected from manipulation.  
 
29 
 5.6 Metrological requirements for indicating and ancillary devices 
5.6.1 Volume conversion 
5.6.1.1 The maximum permissible error for the conve rsion of the measured volume into a volume at 
base conditions or a mass is equal to ± (A – B), A and B being the values specified in Table 2. 
However, the magnitude of the maximum permissible e rror shall not be less than the greater of the two 
following values: 
 one-half (1/2) scale interval of the indi cating device for converted indications; 
 half of the value corresponding to the minimum specified volume deviation Emin. 
5.6.1.2 The total volume at base conditions may be  determined using either of the following two 
methods: 
Method A:   The conversion is performed during the measurement. Each partial volume 
∆Vt,i at working temperature t is converted to the partial  
volume ∆V0,i at base temperature t0 
    ),∆(∆,t ,0 tV Vi iϕ=   
The total volume V0 at base conditions is: 
    ∑=
iiV V,0 0∆  
Method B :  The conversion is done at the end of the measurement,  using the weighted 
average temperature, which is calculated from the working temperatures ti of 
the partial volumes ∆Vt,i: 
   
t,t∆
VV t
tii i∑⋅
=    
The total volume V0 at base conditions is:  
   ),(t 0 tV Vϕ=   
 
5.6.1.3 The utilized conversion function φ(Vt,t) shall be in accordance with the applicable 
International Recommendation or Standards (in par ticular, OIML R 63 [5]), or other methods accepted 
for national use. Annexes C and D (informative) gi ve two examples of the use of such conversion 
functions.  
5.6.1.4 During a transaction, the temperatures of the liquid flowing through the particular delivery 
line shall be measured in proportion to the volume or the time. 
5.6.1.5 If a volume proportional average is used, the partial volumes shall not be greater than one 
fifth of the minimum measured quantity:   
 
30 
   5∆min
t,VVi≤  
5.6.1.6 If a time proportional average is used, the tim e intervals shall not be greater than the time 
needed to measure one fifth of the smallest measured quantity at maximum flow. 
5.6.1.7 The total volume at working conditions is: 
  ∑=
iiV V,t t∆  
5.6.1.8 The maximum permissible error for the dete rmination of the weighted average temperature 
is ± 1 °C for accuracy class 2.5 and ± 0.5 °C for the other accuracy classes. 
Note: In the case of a static volume measurement of the inventory in accordance with 5.1.5.3, the 
corresponding mean temperature of the liquid volume in the tank/compartment has to be 
used for the conversion. 
5.6.1.9  The data underlying the conversion (for instance the density ρo at base conditions or the 
thermal expansion coefficient αo) can be either firmly set or be adjustable depending on the product. 
They shall be protected against manipulations. 
5.6.1.10 If the data according to 5.6.1.9 underlying the conversion can  be adjusted depending on the 
product, the indication and, where appropriate, the printout shall unambiguously indicate which values 
have been used or which liquid has been measured. 
5.6.1.11 The measuring method - with temperature conversion of the volume or without conversion - 
for a given product shall be selected once at the ti me of verification. This selection may not be 
changed later. Similarly, for a given product, onl y one set of conversion da ta may be entered.  
The volume correction factor calculation method utili zed when determining the standard volume of a 
given product, shall not be changed unle ss the relevant standard is modified. 
5.6.2 Indicating device 
5.6.2.1 The reading of the indication shall be preci se, easy and non-ambiguous. The customer shall be 
able to inspect it without particular measures. 
5.6.2.2 The required resolution of indication should be  based on the unit of measure in the form 1, 2 
or 5 ×10n and shall not exceed one tenth of Emin, n being a whole positive or negative number or zero. 
5.6.2.3 The continuous display of the quantity duri ng the period of measurement is only mandatory in 
the case of direct sale to the public. 
5.6.2.4 The output of all measured and calculated va lues shall be possible. Additionally, when the 
volume of a product at base conditions is indicat ed, it shall be possible to access all the values 
underlying the conversion. However, it is not required to permanently indicate all values.   
 
31 
 5.6.2.5 The nature of the indicated quantity (m etering or base condition) shall be unequivocal. 
5.6.2.6 The measuring system may have several un its for indicating the same measuring quantity. 
Each of these indications shall satisfy all the specified requirements. 
5.6.2.7 Other information, not subject to legal metr ological control, may be additionally indicated. In 
such a case, it shall be clearly identified and shall not give rise to false interpretation.  
5.6.2.8 In case of correction of a quantity, the non-corrected quantity shall not be displayed during 
normal operation. The non-corrected quantity sha ll, however, be available for test purposes. 
5.6.3 Price calculation 
Optionally, before or after the delivery, a unit pri ce for a delivered product may be entered. The unit 
price is used to calculate the total price, which may be printed on the delivery note or invoice. 
5.6.4 Printing device 
5.6.4.1 Printing devices are mandatory only for measu ring systems for direct sales to the public. In 
this case, the system shall check be fore the delivery or receipt starts, that a printer is connected (even 
temporarily) and ready for this transaction.  
5.6.4.2 Data to be printed 
If a delivery/receipt document is generated, it shall contain at least the following data:  
 an identifier for the measuring system (e.g. serial number, number plate of the semi-trailer, or 
number of the compartment); 
 the product name or product group name; 
 a unique number, which shall be incremented for each transaction; 
 the volume  Vt at working conditions with the remark “at delivery/receipt temperature” and/or 
the volume V0 “at base conditions”.  
5.6.4.3 Printing of multiple results 
If during a transaction more than one compartment is used for delivery/receipt, all the results may be 
printed on the same delivery/receipt document. If mo re than one result is available for the same 
product, these results may be summed up. 
5.6.4.4 Marking of data 
Verified data shall be enclosed by special characters (e.g. an asterisk “ ”). It is not allowed to enclose 
non-verified data by such special characters. 
The delivery document shall contain the following explanatory note: 
“Data from verified devices are enclosed in asterisks”.  
 
32 
 The remark may either be printed at the time the doc ument is generated, or pr e-printed on the paper or 
the rear side of the paper being used for the printout. 
5.6.5 Memory device 
5.6.5.1 Measuring systems may be fitted with a me mory device to store measurement results until 
their use, or to keep a record of commercial tran sactions, providing proof in the event of a dispute. 
Devices used to read stored information are considered as included in the memory devices. 
5.6.5.2 In the case of measuring systems not used fo r direct sales to the public, the printing device 
may be replaced by a memory device. In this case, a ll data necessary for the printout shall be stored. 
5.6.5.3 The medium on which the data are stored sha ll have sufficient permanency to ensure that the 
data are not corrupted under normal storage conditions. 
5.6.5.4 There shall be sufficient memory storag e for any particular application for which the 
measuring system is used. 
5.6.5.5 Unless otherwise specified, the measured data shall be stored for at least the billing period and 
the period for objection before being erased. If the cap acity of the data memory is exhausted and if 
stored data cannot be erased because the periods specifi ed have not yet elapsed, it shall not be possible 
to start a new measurement.  
5.6.5.6 If the measured data have been printed or tr ansferred out at least once in an acceptable way for 
verification, they may be erased. 
5.6.6 Automatic stop  
If the system is able to stop the delivery or the load ing, it is admissible to automatically terminate the 
delivery or the loading after a given difference, or final quantity, has been reached.  
Note: This option is not a volume pre-setting as described  in OIML R 117 and shall therefore not be 
used for prepaid transactions. It is not n ecessary to reach the given quantity exactly. 
5.7 Additional requirements for meas uring systems with electronic parts 
5.7.1 General requirements 
5.7.1.1 The electronic parts of the measuring syst em shall be designed and manufactured such that 
their errors do not exceed the maximum permissibl e errors (see 5.1.2) under the rated operating 
conditions specified (see 5.1.1).  
 
33 
 5.7.1.2 Disturbances 
Measuring instruments shall be designed and manufact ured such that when th ey are exposed to the 
following disturbances (5.7.1.2.1 and 5.7.1.2.2), either: 
(a) Significant faults do not occur; or 
(b) Significant faults are detected and acted  upon by means of a checking facility: 
5.7.1.2.1 During the following disturbances 
a) Radiated, radio-frequenc y, electromagnetic fields 
b) Conducted radio-frequency fields 
c) Electrostatic discharge 
d) Power frequency magnetic field 
e) Bursts (transients) on power, signal, data and control lines 
f) Surges on signal, data and control lines 
g) AC mains voltage dips, short interruptions and voltage variations 
 
 
5.7.1.2.2 After the following disturbances 
a) Damp heat, cyclic (condensing) 
b) Surges on AC mains power 
c) In the case of a measuring instrument powered by a road vehicle battery via the main ignition switch  
    of the car: 
Transients from DC motors acting as gene rators after the ignition is switched off. 
 
Note: A fault equal to or smaller than the significan t fault is allowed irrespective of the value of 
the error of indication. 
5.7.1.2.3 Application  
The provisions in 5.7.1.2 (a) and 5.7.1.2 (b) may be applied separately to: 
(a) Each individual cause of significant fault; and/or 
(b) Each part of the measuring instrument. 
The choice of whether 5.7.1.2 (a) or 5.7.1.2 (b) is applied, is left to the manufacturer. 5.7.1.2.4 Durability 
The provisions in 5.1.3 and 5.7.1.2 shall be met durably.  
Measuring instruments shall be designed and manufactured such that either:  
 
34 
 (a) Significant durability errors do not occur; or 
(b) Significant durability errors are detected and acted upon by means of a durability protection 
facility. 
The provisions in (a) and (b) may be applied separat ely to each part of the measuring instrument (for 
example: analogue and digital parts). 
The choice of whether (a) or (b) is applied is left to the manufacturer.  
5.7.1.3 Presumption of compliance 
The type of a measuring instrument is presumed to co mply with the provisions in 5.1.3 and 5.7.1.2 if it 
passes the examination and tests specified in Part 2 of this Recommendation. 
5.7.1.4 The significant fault is the greater of th e following two values for the measured volume of 
liquid: 
 1/5 of the maximum permissible error of  the relevant measured quantity; or 
 the minimum specified volume deviation Emin defined according to 2.45. 
5.7.1.5 The following faults are not significant fa ults, even when they ex ceed the value defined in 
5.7.1.4: 
(a) faults arising from simultaneous and mutually independent causes (e.g. electromagnetic fields 
and discharges) originating in the measuring instrument or in its checking facilities; 
(b) faults implying the impossibility to perform any measurement; 
(c) transitory faults being momentary variations in  the indication, which cannot be interpreted, 
memorized or transmitted as a measurement result; 
(d) faults giving rise to variations in the measureme nt result that are serious enough to be noticed 
by all those interested in the measurement result; the relevant Recommendation may specify 
the nature of these variations. 
5.7.2 Power supply device 
5.7.2.1 If the transaction is not interrupted in case the power supply fails, the measuring system shall 
be provided with an emergency power supply device to safeguard all measuring and control functions 
during the failure. 
5.7.2.2 If the transaction is interrupted in case the power supply fails, the requirements of 5.7.2.1 shall 
be met, or the data contained at the time of the fa ilure shall be saved and shall remain displayable for a 
sufficiently long time on an indicating device subject to legal control so that the current transaction 
can be completed. The absolute value of the maxi mum permissible error for the indicated volume in 
this case is increased to 5 % of the minimum measured quantity. 
5.7.2.3 In the case 5.7.2.2, it is also sufficient to  indicate the result of the measurement after re-
establishing the power supply.  
 
35 
 5.7.2.4 Alternatively, in the case of 5.7.2.2, th e transaction may be terminated properly after re-
establishing the power supply. In such a case the maximum permissible errors according to 5.1.2 
apply. 
5.7.3 Checking facilities 
5.7.3.1 The checking facilities serve to detect a disturbance whose effects on the measured volume 
exceed the significant fault according to 5.7. 1.4 and shall have the following effect: 
 automatic correction of the change in volume; or 
 stopping only the faulty device when the measuring system continues to comply with the 
regulations without this de vice being in operation; or 
 stopping the transaction. 
5.7.3.2 During type approval and initial verification it shall be possible to check that the checking 
facilities function correctly, e.g.: 
 by disconnecting the sensor; or 
 by interrupting the signaling circuit; or 
 by interrupting the power supply. 
5.7.3.3 The checking facility for the functioning of the calculator checks the va lues of all permanently 
stored instructions and data as well as all procedur es for the internal transmission and storage of the 
data relevant to the measurement re sult and shall be of type I or P. 
5.7.3.4 The checking facility for the correctness of the calculations carried out by the computer shall 
be of type P. This check can be carried out, for exam ple, with the aid of a parity bit, a checksum or 
double storage.  
5.7.3.5 The checking facility for the indicating device shall ensure that a failure or mal-operation of 
individual elements is detected visually and/ or automatically or cannot lead to erroneous 
interpretation. The automatic detection can, for exam ple, take place by monitoring the current between 
the segments of LED displays or by measuring the grid voltage of fluorescent displays. The visual 
check can, for example, be carried out by redundant LC segments (graphics LCD) or a black-and-
white test.  
5.7.3.6 It shall be possible during initial verificati on to check the checking facility for the indicating 
device, for example, by disconnecting the whole or part of the indicating device (in the case of an 
automatic checking facility) or by a visual check of a manually or automatically triggered black-and-
white test. 
5.7.3.7 Checking facilities for ancillary  devices (e.g. according to 5.6.2 to 5.6.5) shall ensure that the 
particular ancillary device is available, if necessary,  and that the transmission of the data is valid.  
5.7.3.8 The checking facility for a printing device  shall also monitor the presence of paper.   
 
36 
  
6 PLATES, DOCUMENTS AND SEALING 
6.1 Identification plate 
6.1.1 Each tank shall be provided with an identification plate, which is clearly visible and easily 
legible. The plate shall not be of a material that  deteriorates under the rated operating conditions of the 
tank and should allow the data to be easily inscribed. The plates shall be fixed in such a way that they 
cannot be removed without breaking the seals of the Legal Metrology Service. 
6.1.2 The following information sh all be inscribed on the plate: 
 name or trademark of the manufacturer; 
 type and year of manufacture (year may be given as part of a serial number); 
 serial number of the tank; 
 serial number of the level gauging system, if appropriate; 
 type approval number, if appropriate; 
 nominal capacity of the tank or of each compartment; 
 accuracy class if other than 0.5; 
 minimum measured quantity of the tank or of each compartment; 
 base temperature; 
 range of specified inclination, if it differs from 2 %. 
6.1.3 A free area shall be left on the plate fo r the verification marks, according to national 
regulations.  
6.2 Measuring system document 
6.2.1 Upon initial verification of a measuring system, a measuring system document shall be drawn 
up. This document shall contain at least: 
 sealing plan; 
 pipework diagram; 
 pneumatics diagram with the metrologica lly significant control lines marked; 
 calibration parameter printout and calibration tables, if applicable; 
 extra sheets with descriptions of changes to  the measuring system, repairs as well as any 
breaking of official seals including their confirmations; 
 signatures for the software relevant to veri fication and its parameters, if applicable. 
6.2.2 The measuring system document is part of the measuring system and shall be kept on the 
tanker.  
 
37 
 6.3 Tank capacity plate on tanks with di psticks scaled in non-volumetric units 
The measuring system document may be replaced by a tank capacity plate for the tank or for each 
compartment. In such a case, the tank capacity plate shall be fixed on the tank and bear the following 
information: 
 institution which calibrated the tank a nd prepared the tank capacity table; 
 calibration certificate number; 
 base temperature; 
 number of heating coils, if appropriate; 
 tank capacity table (as a function of V(h) or V(C)). 
6.4 Verification certificate 
6.4.1 In conformity with national regulations  a verification certificate may be required.  
6.4.2 In the case of road tankers, the verification cer tificate shall include the following information: 
 issuing authority and certificate number; 
 name and, if appropria te, address of holder; 
 manufacturer’s name or trademark, type, year of manufacture and serial number; 
 vehicle registration number, if appropriate; 
 number of compartments and h eating coils, if appropriate; 
 identification of the reference point and the vertical measurement axis, if appropriate; 
 method of calibration used, number of the calibra tion certificate for the standard installation 
used; 
 convention relating to the filling of the discharge  pipes, and if appropriate, indication of the 
presence of a manifold; 
 uncertainty of the determination of the va lues of volume indicated in the certificate; 
 date of issue and limit of validity of the verification certificate, if a limit is set ( Note : a period 
of validity of 2 to 5 years is recommended); 
 title, name and signature of the pers on responsible for the verification; 
 sketch indicating the meaning of the symbols used; 
 height of coupling during verification (for semi trailers only); 
 number and positions of the a pplied verification marks. 
For each compartment, the verification certificate shall indicate: 
 nominal capacity; 
 total capacity; 
 ullage height corresponding to the nominal capacity, in mm; 
 reference height, in mm; 
 sensitivity of the tank at the level of the nominal capacity or tank capacity table, in legal units 
of measurement.   
 
38 
 6.4.3 In the case of rail tankers, the calibration cer tificate shall include the following information: 
 issuing authority and certificate number; 
 registration number of rail tanker; 
 name and, if appropriate, addr ess of owner and manufacturer; 
 method of calibration, if appropriate, and date and place of the tests; 
 identification of the reference point and the vertical measurement axis; 
 conventions concerning filling of the tank and discharging pipework; 
 reference height, in mm; 
 total contents and corresponding ullage height; 
 capacity of the tank body, up to the upper intern al generator, and corresponding ullage height; 
 reference temperature (on which the table is based); 
 uncertainty of the determination of the values indicated in the certificate; 
 limit of validity of the certificate as regards the use of the tank as a measuring instrument 
(Note : a period of validity of 4 to 5 years is recommended); 
 date of issue of the verification certificate; 
 title, name and signature of the pers on responsible for the verification; 
 sketch indicating the meaning of the symbols used; 
 tank capacity table giving, in legal units, the vol ume of the liquid contained in the tank against 
the ullage height or the liquid height expressed  in mm, within the range of level gauging; 
 number and positions of the a pplied verification marks. 
6.5 Seals 
6.5.1 All measuring systems shall be sealed in su ch a way that manipulations can be prevented 
and/or detected. The following locations for seals are recommended: 
 indicating devices of the level gauging system; 
 controller and interface units; 
 terminal boxes with cables relevant to the measurements (e.g. for temperature and liquid 
detector); 
 inclination sensors; 
 temperature sensors; 
 liquid detectors, except those requiring removal for cleaning; 
 dipsticks on the upper and lower fastenings, where relevant; 
 identification plate of the measuring system, operating instructions and pneumatic and 
pipework diagram, if applicable; 
 dome cover and man holes of tank compartments in measuring systems which can be filled 
from the bottom only. 
Heating coils, if provided, shall be sealed at  their points of junction with the tank body. 
6.5.2 Seals are not applied to the pipework system.  
 
39 
 6.5.3 The locations for seals shall be arranged such  that the sealing and the external administrative 
examination are possible without hindrance. They are fixed individually for each type of measuring 
system within the type approval certificate.  
 
40 
 7 BIBLIOGRAPHY 
 
[1]  International Vocabulary of Basic and General Terms in Metrology  (VIM). BIPM, IEC, 
IFCC, ISO, IUPAC, IUPAP and OIML. Intern ational Organization for Standardization, 
Geneva, 1993; 
[2]  International vocabulary of terms in legal metrology  (VIML). OIML, Paris, 2000; 
[3]  OIML International Recommendation R 117 Measuring systems for liquids other than water . 
OIML, Paris, 1995 (Revised in 2007); 
[4] Guide to the expression of uncertainty in measurement . BIPM, IEC, IFCC, ISO, IUPAC, 
IUPAP and OIML. International Organiza tion for Standardization, Geneva,1995; 
[5] OIML International Recommendation R 63 Petroleum measurement tables  (with reference to 
the ISO International Standard 91-1:1982 & 91-2:1991). OIML, Paris, 1994; 
[6] OIML International Document D 11 General Requirements for electronic measuring 
instruments . OIML, Paris, 2004.  
 
41 
 8 INDEX 
A 
2.4 Additional device  
2.3 Ancillary device 2.4 Anti-swirl device 
2.57 Automatic checking facility 
B 
2.22 Baffle 
2.41 Base conditions 
2.36 Bottom loading 
2.4 Branches or bypasses 
2.34 Built-in manifold 
C 
2.56 Checking facility  
2.33 Collector (manifold) 
2.3 Conversion device 
D 
2.29 Damping tube 2.35 Direct discharger 
2.47 Disturbance 2.31  Dry hose 
2.53 Durability 
E 
2.5 Electronic part 
2.31 Empty hose 
2.11 Error of indicated volume 
2.8 Expansion volume   
 
42 
 F 
2.48  Fault 
2.4 Filter 
2. 32 Full hose  
G 
2.4 Gas elimination device 
2.4 Gas indicator 
H 
2.4 Hoses 
I 
2.26 Inclination sensor 
2.10 Indicated volume (Vi) 2.52 Influence factor 2.46 Influence quantity 2.55 Initial intrinsic error  
2.59 Intermittent automatic checking facility (type I) 
2.54 Intrinsic error 
L 
2.23 Level sensor 
2.42 Liquid detector 2.19 Liquid height (h)  2.43 Liquid indicator 
2.13 Liquid level 
2.27 Longitudinal axis and pitch angle  
 
43 
 M 
2.4 Manifold 
2.24 Measuring range of the level sensor 2.3 Memory device 
2.44 Minimum measured quantity MMQ ( V
min) 
2.45 Minimum specified volume deviation ( Emin) 
N 
2.6 Nominal capacity (of the tank or compartment) ( Vn) 
P 
2.58 Permanent automatic checking facility (type P) 
2.3 Price indicating device 2.3 Printing device 
2.4 Pump 
R 
2.50 Rated operating conditions  2.51 Reference conditions  
2.17 Reference height ( H) 
2.14 Reference point 2.16 Reference point bottom (RPB) 2.13 Reference point top (RPT) 
2.39 Reference position 
2.3 Repeating indicating device 
2.28 Roll angle 
S 
2.4 Sampling device 
2.20 Sensitivity of a tank 2.4 Sight glass 2.49 Significant fault  2.2 Static measuring system   
 
44 
 T 
2.21 Tank capacity table 
2.12 Tank or compartment calibration (Tank calibration) 2.25 Temperature sensor 
2.36 Top loading 
2.7 Total capacity  2.38 Transaction 2.30 Transfer point 2.1 Transportable measuring tank 2.28 Transverse axis and roll angle 2.9 True volume ( V
t) 
U 
2.18 Ullage height ( C) 
V 
2.4 Valves 
W 
2.32  Wet hose 
2.40 Working conditions  
Z 
2.3 Zero-setting device  
 
45 
 Annex A 
Examples for tankers with mechanical sensors 
(Informative) 
  
 
46 
  
  
 
 
  
 
  
 
47 
    
 
48 
  
 
 
Fig. A.1 Single or two (opposite) volumetric marks or indexes in the dome 
 
 
 
 
Fig. A.2 Top edge of the index fi xed on holder (one-mark dipstick) 
  
 
49 
  
 
 
   
Fig. A.3 Single mark or graduated window in dome Section A-A  
 
50 
  
  
 
 
Fig. A.4 Single volumetric mark in tank (on console fixed to dome) 
   
 
51 
 
 
 
Fig. A.5 Mechanical dipstick with sliding index 
 
  
 
52 
 
 
Fig. A.6 Examples of mechanical dipsticks a nd placement of RPT (Ullage height measurement)  
 
53 
 
 
   
 
     
 
    
Fig.A.7 Examples of mechanical dipsticks and placement of RPT 
(Liquid height measurement) 
 
  
 
 
 
 
Fig. A.8 Slip gauge (overflow mark) for a beer transport tank 
 1 
5 Vt 
Vn 
h H RP
T Manhole   
 
54 
 Annex B 
Examples for automatic measuring systems 
with electronic level gauging 
(Informative) 
 
Fig. B.1 Schematic setup of the measuring system of a tanker for oils in its maximum version  
(for explaining the basic components and functions)  
 
(1) level sensor 
(2) measuring tank/measuring compartment 
(3) float, if appropriate 
(4) product 
(5) bottom valve 
(6) discharge line 
(7) dry coupler (API) 
(8) liquid detector (if appropriate, in co llector line and downstream of pump) 
(9) collector vent valve  
(10) collector line (shown with valve function) 
(11) filter system 
(12) pump 
(13) level sensor for pipe system, alternatively: gas separator  
 
55 
 (14) draining, if appropriate 
(15) valve of empty hose  
(16) coupler of empty hose with filter a nd inspection glass (alternative positions) 
(17) hose reel with full hose  
(18) valve of full hose 2 
(19) valve of full hose 2 (reduced delivery without shutdown valve) 
(20) valve of full hose 1 
(21) non-return valve 
(22) temperature sensor 
(23) ventilation, if appropriate 
(24) electronic measuring and control unit 
(25) control apparatus for pump motor, if necessary 
(26) delivery line to the right, if appropriate  
 
56 
 Fig. B.2 Schematic setup of the measuring system of a road tanker for milk in  
its maximum version (for explaining the basic components and functions)  
 (1) level sensor 
(2) measuring tank/measuring compartment 
(3) float, if appropriate 
(4) valve for compartment 1 
(5) pipe empty sensor  
(6) valve for pumping to the trailer 
(7) valve for compartment 2…n 
(8) valve for pumping to the trailer 
(9) valve for pumping to the trailer 
(10) non-return valve 
(11) transfer point sensor  
(12) transfer point with inspection glass 
(13) pump with control apparatus for pump motor, if necessary 
(14) suck bottle 
(15) pressure air valve 
(16) suck bottle level sensor 
(17) vacuum valve 
(18) suck bottle clearing valve 
(19) milk sampling system 
(20) pressure air valve 
(21) mainstream suck valve 
(22) temperature sensor  
 
57 
 (23) vacuum sensor 
(24) suction hose 
(25) suction lance 
(26) electronic measuring and control unit  
 
58 
 Annex C 
Examples for volume conversion from  
observed temperature to 15 °C (from working to base conditions) – 
petroleum products and lubricants 
(Informative) 
The volume conversion of mineral oils is based on the following rules: 
 Product group Tables Conversion equation 
Generalized petroleum 
products 
Correction of volume to 
15 °C against density at 
15 °C B Manual of petroleum  
measurement standards 
Chapter 11.1.54.4 – Volume 
correction factors 
ASTM D 1250-80 
Volume VIII, Table 54B  
Chapter 11.1.54.4 – 6 
 
ASTM D 1250-80 
Volume X 
Generalized lubricating oils
Correction of volume to 
15 °C against density at 
15 °C D Manual of petroleum 
measurement standards 
Chapter 11.1.54.10 – Volume 
Correction Factors 
ASTM D 1250-82 
Volume XIV, Table 54D  
Chapter 11.1.54.10 
 
ASTM D 1250-82 
Volume XIV 
 
The conversion (volume correction factor) is based on the following constants: 
 Product 
group Oil group Range of density  
[kg/m³] K0 
[(kg/m³)²/°C] K1 
[(kg/m³)/°C] Function 
Petrol 
Naphtha 60.,0 – 770.4 
770.5 – 787.5 346.4228 
– 0.00336312 0.4388 
2680.3206 2.2 
2.3 
Jet-A-1 
Kerosene 787.6 – 83.,5 594.5418 0.0 2.2 Generalized 
petroleum 
products B 
Fuel oil 838.6 – 1200.0 186.9696 0.4862 2.2 
Generalized 
lubricating oils D Lubricants 750.0 – 1164.0 0.0 0.6278 2.2 
  
 
59 
 The volume correction factor (VCF) for product group B and D: 
 [] ) 8,01(15 15
15t t EXP VCFt
t ∆××+×∆×−== α αρρ 
where 
 
151
2
1515ρραK Ko+=  
or 
 2
151
15ραKKo+=   
 
60 
 Annex D 
Examples for volume conversion from observed temperature to 15 °C 
(from working to base conditions) – Liquefied petroleum gas (LPG)  
(Informative) 
 
The volume conversion of liquefied petroleum gas is based on the following rules: 
 Product group Tables Conversion function 
Generalized light products 
(LPG) 
Correction of volume to 
15 °C against density at 
15 °C X Density determination 
(54 X) 
 DIN 51 757 
Annex B and Annex G 
 
The constants P1, P2 and P3 used to calcula te the volume correction factor (VCF) are: 
Range of density  
kg/m³ P1 P 2 P 3 P 4 
500 to 600 4075.0 × 10-3 5050.0 × 10-6 27.5 × 10-3 45.0 × 10-6 
> 600 to 620 2448.9 × 10-3 2340.9 × 10-6 1.589 × 10-3 1.947 × 10-6 
> 620 to 640 2225.1 × 10-3 1980.0 × 10-6 1.588 × 10-3 1.946 × 10-6 
> 640 to 650 1936.6 × 10-3 1529.1 × 10-6 1.588 × 10-3 1.946 × 10-6 
 
The volume correction factor (VCF) for product group X: 
 
2
153
4
151
2
15) ( ) (1 tPPtPP VCFt
t ∆×−+∆×−+==ρ ρ ρρ 
where 
 
∆t = t – 15  
 
61 
 Annex E 
Density and volume (of 1 kg) of distilled water (Informative) 
Temperature  Density Volume of 1 kg 
°C kg/m3 L 
0 999.8428 1.00016 
1 999.9017 1.00010 
2 999.9429 1.00006 
3 999.9672 1.00003 
4 999.9749 1.00003 
5 999.9668 1.00003 
6 999.9431 1.00006 
7 999.9045 1.00010 
8 999.8513 1.00015 
9 999.7839 1.00022 
10 999.7027 1.00030 
11 999.6081 1.00039 
12 999.5005 1.00050 
13 999.3801 1.00062 
14 999.2474 1.00075 
15 999.1026 1.00090 
16 998.9459 1.00106 
17 998.7778 1.00122 
18 998.5984 1.00140 
19 998.4079 1.00159 
20 998.2067 1.00180 
21 997.9950 1.00201 
22 997.7730 1.00223 
23 997.5408 1.00247 
24 997.2988 1.00271 
25 997.0470 1.00296 
26 996.7857 1.00322 
27 996.5151 1.00350 
28 996.2353 1.00378 
29 995.9465 1.00407 
30 995.6488 1.00437 
31 995.3424 1.00468 
32 995.0275 1.00500 
33 994.7041 1.00532 
34 994.3724 1.00566 
35 994.0326 1.00600 
36 993.6847 1.00636 
37 993.3290 1.00672 
38 992.9654 1.00708 
39 992.5941 1.00746 
40 992.2152 1.00785  
 
62 
 Tanaka, M.; Girard, G.; Davis, R.; Peuto, A.; Bignel, N.:  Recommended table for the density of water between  
0 °C and 40 °C based on recent experimental reports. Metrologia, 2001, 38, 301-309