Czech Metrology Institute  
Okružní 31, 638 00 Brno  
 
1. ------IND- 2018 0335 CZ - EN- ------ 20180803 --- --- PROJET 
Executive summary for the EC (not part of this legislation)  
Liquid transport tanks are placed on the market and put into use in the Czech Republic pursuant to 
Act No  505/1990 on metrology, as amended.  
The subject of this notified regulation is to lay down metrological and technical requirements for 
these measuring instruments.  This regulation also stipulates tests for type a pproval and verification.  
(End of executive summary.)  
 
Contact person:  Hendrych Tomáš, 
Mgr.  
Phone : 545  555 414 
 
PUBLIC DECREE  
 
As the authority with substantive and territorial jurisdiction in the matter of defining metrological and 
technical requirements  for specified measuring instruments and stipulating test methods for type 
approval and verification of specified measuring instruments pursuant to §  14(1) of Act No  505/1990 
on metrology, as amended, and in accordance with the provisions of §  172 et seq. of Act No  500/2004, 
the Code of Administrative Procedure, as amended (hereinafter the 'CAP') the Czech Metrology Institute 
(CMI) commenced ex officio proceedings on 26  February  2016 pursuant to §  46 of the CAP, and, based 
on supporting documents, issues th e following:  
 
 
I. 
DRAFT GENERAL MEASUR E 
Number: 0111 -OOP -C067 -16 
 
laying down the metrological and technical requirements for legally controlled measuring 
instruments, including testing methods for type approval and verification of the following legally 
controlled measuring instruments:  
'liquid transport tanks'  
 Measure of a General Nature No  0111 -OOP -C067 -16 
2 1 Basic definitions  
For the purposes of this General Measure, the terms and definitions according to VIM and VIML1 and 
the following definitions apply:  
1.1 
liquid transport tank (cistern)  
a tank used to transport liquids and simultaneously as a volume measurement device for liquids with 
maximum viscosity of 20  mPa·s at measurement temperature, permanently installed on a road or railway 
vehicle or removable, which may be divided into several measur ing chambers  
1.2 
static measuring system  
a system comprising the measuring tank itself and attached and auxiliary devices. A  static measuring 
system can also be used to determine calculated values for liquids  
1.3 
connected device  
a device intended for the performance of individual functions directly related to processing, transmitting  
or displaying measurement results  
Examples of connected devices:  
 a zeroing device;  
 a repeating indicator;  
 a printer;  
 a recording device;  
 a price indicator;  
 a conversion appara tus. 
1.4 
auxiliary device  
a part or device other than a connected device required to achieve correct measurement, or intended for 
facilitating measurement operations, or that can influence measurement in any way  
Examples of auxiliary devices:  
 a sampling apparatus;  
 a gas indicator;  
 a sight -glass;  
 a filter or pump;  
 a gas separator;  
 a device used for a transmission point;  
 an anti -swirl device;  
 branches or by -passes;  
 valves, hoses.  
                                                      
1 TNI 01 0115 International Vocabulary of Metrology —Basic and General Concepts and Associated 
Terms (VIM) and International Vocabulary of Legal Metrology (VIML) are part of the technical 
harmonisation compendium ‘Terminology in the field of metrology’, which  is publicly available at 
www.unmz.cz . Measure of a General Nature No  0111 -OOP -C067 -16 
3 
 1.5 
nominal volume  
the volume marked on the tank or on its chamber that usually corresponds to the volume of liquid in the 
tank or chamber at reference temperature if the tank is filled to its maximum permissible level or volume 
mark  
NOTE The  nominal volume value may be restricted by safety regulations.  
1.6 
total tank volume  
the maximum amount of liquid the tank or chamber can contain before it overflows, under reference 
temperature  
1.7 
expansion volume of a tank  
the difference between total and nominal volume  
1.8 
true tank volume  
the conventional value of the volume of liquid in the tank or chamber at operating temperature  
1.9 
indicated volume  
the volume value provided by a volumetric measurement system  
1.10 
indicated volume error  
the difference between the indicated volume of the tank or chamber and the true volume  
1.11 
tank calibration  
a set of operations performed to determine the volume of the tank or chamber, using methods that meet 
technical and metrological requirements, such as measurement at one or more filling levels using 
measurement of geometric dimensions, gravimet ric or volumetric methods  
1.12 
liquid level  
the open surface of the liquid whose volume is being measured  
1.13 
reference point  
an easily identifiable point on a vertical measurement axis to which the measured liquid level relates  
1.14 
top reference point ( RPT)  
a reference point in the upper part of the tank, under normal operating conditions above the surface of 
the liquid  Measure of a General Nature No  0111 -OOP -C067 -16 
4 1.15 
bottom reference point (RPB)  
a reference point in the lower part of the tank, under normal operating conditions below the surface o f 
the liquid  
1.16 
reference height ( H) 
the distance between the top and bottom reference point, measured along the vertical measurement axis  
1.17 
open space height ( C) 
the distance between the surface of the liquid and the top reference point, measured along the vertical 
measurement axis  
1.18 
liquid height ( h) 
the distance between the surface of the liquid and the bottom reference point, measured along the vertical 
measurement axis  
 
Figure  1 - Tank schematic for specification of points according to defi nitions  1.12 to 1.18  
Výška hladiny kapaliny h  Liquid level height h  
Výška volného prostoru C  Open space height  C 
Referenční výška H  Reference height  H 
Horní referenční bod RPT  Top reference point  RPT 
Dolní referenční bod RPB  Bottom reference point  RPB 
Hladina kapaliny  Liquid level  
Measure of a General Nature No  0111 -OOP -C067 -16 
5 
 1.19 
tank sensitivity  
the change in liquid level  Δh divided by the corresponding relative change in volume  ΔV/V of volume 
V contained in height h 
1.20 
calibration table  
a table that shows the relationship between the liquid level and the volume of liquid contained in the 
tank (chamber) at this height under reference conditions (including tank position)  
1.21 
baffle  
an internal device in a tank or chamber, for example a partition inside the tank, that is used to reduce the 
move ment of liquid during transport and to increase the mechanical stability of the tank  
1.22 
level sensor  
a device that measures the level of liquid in a tank or chamber.  
1.23 
level sensor measurement range  
the range between the minimum and maximum indication  of the level sensor. The  lower limit depends 
on the type and system and must be significantly higher than the liquid level corresponding to the 
smallest measured amount in the tank or chamber. The  upper limit depends on tank height and must be 
greater than the maximum permissible filling height of the tank or chamber.  
1.24 
tilting sensor  
a device to measure longitudinal and transverse angles  
1.25 
longitudinal axis and longitudinal angle  
the tank's axis of symmetry parallel to the tank's main direction of movement in its normal position.  The 
vertical angle of rotation of the axis is called the longitudinal angle. It  is positive when the front part of 
the tank rises.  
1.26 
transverse axis and transvers e angle  
the tank's horizontal axis, perpendicular to its longitudinal axis in normal position.The vertical angle of 
rotation of the axis is called the transverse angle. It  is positive when the right part of the tank rises 
(relative to the direction of move ment).  
1.27 
baffle pipe  
a mechanical device (usually shaped like a pipe with openings) used to reduce or eliminate the effect of 
surface waves on level measurement and to protect the level sensor from physical damage  
1.28 
transfer point  
the point from whic h the liquid is defined as delivered or received  Measure of a General Nature No  0111 -OOP -C067 -16 
6 1.29 
empty hose  
a hose connection that only contains liquid product during a transaction, and is usually completely 
emptied prior to completion of the transaction. It  is attached past the transfer point in d ispensing systems 
(before the transfer point in receiving systems)  
1.30 
full hose  
a hose connection filled with liquid product prior to and after a transaction. In  this case the transfer point 
is situated near the outlet from the full hose.  
1.31 
distributo r (collector)  
an apparatus interconnected with valves with outlets from measuring chambers that allows delivery from 
one or more chambers through one common pipe  
1.32 
direct output  
a cistern vehicle with gravity unloading, every separate measurement chambe r has its own outlet. A  
filling connector is often used as an outlet.  
1.33 
top filling  
filling the measuring chamber from above through a filling opening that is opened for this use  
1.34 
bottom filling  
filling the measuring chamber from the bottom via a st andardised dry connector (for example an API 
adapter) and via a foot valve that is built into the bottom of the measuring chamber and opened for this 
use 
1.35 
transaction  
delivery of a liquid product from one or more measuring chambers to the recipient. A  transaction can 
also involve receiving (for example a milk collection vehicle).A transaction is complete if the parties to 
the transaction have approved it regarding the amount of the transaction. This  can be payment, signature 
of a cheque, signature of a bill of delivery, etc. The parties to the transaction can be the parties 
themselves or their representatives.  
1.36 
reference position  
the position for delivery from (or filling) the measuring tank in accordance with the design drawing. 
This is the basis for the corrective function of tilting. The  zero tilt point is the zero point for both 
(longitudinal and transverse) tilts.  
1.37 
measurement conditions  
the conditions under which liquid volume is measured (e.g. temperature, viscosity, tank position)  Measure of a General Nature No  0111 -OOP -C067 -16 
7 
 1.38 
basic conditions  
specific conditions for which the measured volume is recalculated (e.g. temperature, density)  
1.39 
liquid detector  
a device used to detect the presence of liquid in a pipe or tank and for testing prior to start and after 
completion whether all parts of the measurement system are either entirely filled with liquid (a full -hose 
system) or entirely empty (an empty -hose system)  
1.40 
liquid indicator  
a device used to indicate the presence of liquid in a pipe (for example a sight -glass) 
1.41 
minimum measured quantity (MMQ)  
the smallest volume of liquid for which measurement is metrologically permissible for the tank, or 
separately for each chamber. It  must be stipulated only for a measurement system suitable for measuring 
individual  volumes. Alternatively , the expressions ‘minimum delivery’ or ‘minimum offtake’ may be 
used.  
1.42 
minimum nominal volume deviation ( Emin) 
double the absolute value of the maximum permissible error for the minimum measured quantity of the 
tank or chamber  
2 Metrological requirements  
Metrological requirements are based on the requirements of OIML  R 80-1 'Road and rail tankers with 
level gauging. Part  1: Metrological  and technical requirements2'. 
2.1 Rated operating conditions  
Rated operating conditions are pr esented in Table  1. 
Table  1 - Rated operating conditions  
Ambient temperature  minimum  −25 °C (1)  
maximum  +55 °C (1)  
Humidity  up to condensation  
(1) This value is stipulated by a national authority according to the country's climate.  
The reference temperature of the liquid in the tank is +15  °C or +20  °C and the reference pressure is 
normal atmospheric pressure. For  justified reasons other values may also be used (for example a 
reference temperature of +12  °C and a higher pressure for liquefied petroleum gas).  
                                                      
2 OIML  R 80-1 'Road and rail tankers with level gauging. Part  1:Metrological and technical 
requirements' —publicly available at  www.oiml.org  Measure of a General Nature No  0111 -OOP -C067 -16 
8 2.2 Measuring interval  
The measuring interval is stipulated by the measuring instrument's manufacturer.  
2.3 Maximum permissible error  
2.3.1 Classification of accuracy classes and maximum permissible error  
Depending on the area of use of a static measuring system situated on an undercarriage, the accuracy 
class is determined according to Table  2. 
Table  2 - Accuracy class for measuring systems on road cisterns:  
Class  Area of use  
0.5 Measuring systems for the transport and supply of low-viscosity liquids ( 20 mPa·s) stored at 
atmospheric pressure, with the exception of potable liquids.  
Measuring systems for milk, beer  and other foamy liquids.  
Measuring systems for dispensing fuel into aircraft.  
1.0 Measuring systems for liquefied pressurised gases measured at −10  °C or higher.  
1.5 Measuring systems for liquid carbon dioxide.  
Measuring systems for liquefied pressurised gases measured at less that −10  °C. 
2.5 Measuring systems for liquids at temperatures below −153  °C. 
Table  3 - Maximum permissible errors  
Measuring instrument (part 
thereof)  Maximum permissible error for accuracy class  
0.5 1.0 1.5 2.5 
A Static measuring system  0.5 % 1.0 %  1.5 %  2.5 %  
B Measuring transport tank  0.3 % 0.5 %  1.0 %  1.5 %  
The maximum permissible error from row A of Table  3 is used for the entire measuring system, under 
measuring conditions, without any adjustment between various tests, for:  
 type tests;  
 initial verification;  
 subsequent verification.  
The maximum permissible error from ro w B of Table  3 is used for:  
 measuring tank type tests under measurement conditions; and  
 tank verification prior to initial verification of the measuring system.  
For measured volumes between the minimum measured quantity and double the minimum measured 
quan tity, the absolute value of the maximum permissible error does not have to be smaller than the 
minimum nominal volume deviation.  
The minimum measured quantity is defined only for tanks intended for sub -measurements.  
The minimum measured quantity must be de termined for each chamber and must not be greater than 
one fourth (1/4) of this nominal volume.  
The minimum measured quantity must be equal to or greater than the greater of the following values:  
 the volume corresponding to the difference in levels in Table  4 in the area of minimum 
sensitivity;  Measure of a General Nature No  0111 -OOP -C067 -16 
9 
  the volume calculated as the change caused by manufacturing volume tolerances (between true 
and design geometry) must not exceed three -fifths (3/5) of the maximum permissible error 
specified in row  A of Table  3 for every permissible tilt angle.  
Table  4 
--- Accuracy classes  
0.5 1.0 1.5 2.5 
Difference in levels (mm)  200 171 190 200 
NOTE Differences in levels are derived from the extended uncertainty for corresponding accuracy classes 
given in Table  7. 
The minimum measured quantity of a measuring system must be expressed in one of the following ways:  
a) 1 10n, 2 10n or 5 10n litres, where n is a whole number;  
b) a whole multiple of 100  litres.  
The reference height of the tank or chamber must not change during f illing by more than the greater of 
the values given in Table  5. 
Table  5 
--- Accuracy classes  
0.5 1.0 1.5 2.5 
Maximum permissible 
change in reference height H 
(mm)  2 mm or 
H/1000  4 mm or H/500 
The volume of the chamber must not change by more than one-third (1/3) of the maximum permissible 
error in row  B of Table  3 due to the filling or emptying of an adjacent chamber.  
Tank material must be such that a change in the tank's volume due to a change in temperature of ±10  °C 
from the reference temperatur e is not greater than 1/3 of the maximum permissible error in row  B of 
Table  3. 
Tanks for liquids not measured under atmospheric pressure must be designed so that a change in pressure 
over the entire permissible range does not cause a change in volume grea ter than 1/5 of the maximum 
permissible error in row  B of Table  3. 
The volume of liquid remaining in the tank or chamber after it has been completely emptied must not 
be greater than one -tenth of the absolute value of the maximum permissible error in row  B of Table  3 
applied to the volume of the tank or chamber.  
The hysteresis of the level sensor must not exceed one -third of the sensitivity given in Table  6 for tanks 
for delivering an entire chamber, or one -third of the extended uncertainty given in Table  7 for partial 
delivery, or its influence can be included in evaluation of the uncertainty.  
The shape of the tank for delivering an entire chamber must be such that in the area of level measurement 
sensitivity is equal to or greater than specified in Table  6. 
Table  6 
Tanks for delivering an entire chamber  Accuracy classes  
0.5 1.0 1.5 2.5 
Minimum tank sensitivity Δh for ΔV/V  in mm 
(1/1 000 of measured volume)  1.5 1.0 0.5 0.3 Measure of a General Nature No  0111 -OOP -C067 -16 
10 The top and bottom reference point must be clearly defined and implemented.  
It must be possible to measure the level of the contained liquid manually. The  measuring rod must be 
vertical.  
The extended uncertainty of level measurement for partial delivery must not exceed the values specified 
in Table  7. 
Table  7 
Tanks for partial del ivery  Accuracy classes  
0.5 1.0 1.5 2.5 
Level measurement uncertainty Ux in mm 0.7 1.2 2.0 3.5 
The extended uncertainty of measurement Ux is stipulated in accordance with special legislation3 as the 
standard uncertainty of measurement multiplied by an extension coefficient k = 2, which for a normal 
distribution corresponds to a probability of 95  %. 
The indication resolution for level measurement must be in accordance with Table  8. 
Table  8 
--- Accuracy classes  
0.5 1.0 1.5 2.5 
Maximum resolution value for level indication in mm  0.1 0.2 0.5 1.0 
The submersion of the float within the permissible density range of the measured liquid (specified in the 
type-approval certificate) must not change by  more than is specified in Table  9.Measuring systems 
without appropriate correction of submersion due to changes in liquid density have this influence 
included in the level measurement uncertainty.  
Table  9 
Maximum change in float submersion in mm for  Accur acy classes  
0.5 1.0 1.5 2.5 
- partial deliveries  0.5 0.8 1.6 2.5 
- delivery of the entire chamber  1.5 2.4 4.8 7.5 
For ultrasound level sensors, within the permissible range of properties of the measured liquid (specified 
in the type -approval certificate), the measured height must not change by more than that specified in 
Table  7.To convert the level measurement result to volume, an electronic data processing system must 
have a calibration table stored, containing level/volume pairs fo r every measuring chamber. The  number 
and spacing of these values depends on tank geometry. Intermediate  values are calculated using 
appropriate interpolation. Extrapolation  is not permitted.  
The range of levels in the calibration table must cover all rout ine operating situations. Filling  the 
measuring chamber above the highest permissible point must be prevented, or must be considered a 
fault.  
                                                      
3 'Guide to the expression of uncertainty in measurement' (GUM).  Measure of a General Nature No  0111 -OOP -C067 -16 
11 
 The calibration table is determined by gradually filling or emptying every chamber in the normal 
position. If  a tank is equipped with a device to correct the influence of tilt on volume, it must not exceed 
the minimum nominal volume deviation over a range of ±4° (longitudinally and laterally).  
The calibration table, as well as tilt correction data, must be stored in t he system and protected from 
tampering.  
The total volume under basic conditions can be determined using one of these two methods pursuant to 
the appropriate technical standard (OIML)4: 
Method  A: Conversion  is performed during measurement. Every  partial volume ΔV t,i is converted to 
ΔV 0,i: 
The total volume under basic conditions is given by the equation:  
Method  B: Conversion is performed at the end of measurement using the weighted average temperature, 
calculated from temperatures ti of partial volumes ΔV t,i: 
The total volume under basic conditions is given by the equation:  
During a transaction the temperature of the flowing liquid is measured:  
a) proportionally to volume —partial volumes must not be greater  than one -fifth of the minimum 
measured quantity;  
b) proportionally to time —the time interval must not be greater than the time needed to measure 
one-fifth of the minimum measured quantity at maximum flow rate.  
The total volume under measurement conditions is given by the equation:  
2.3.2 Maximum permissible errors of measuring system elements  
The maximum permissible errors for determining the weighted average temperature are specified in 
Table  10. 
Table  10 
--- Accuracy classes  
0.5 1.0 1.5 2.5 
Maximum permissible error in determining 
temperature  ±0.5 °C ±1.0 °C 
                                                      
4 OIML  R 63 Petroleum and petroleum product calibration tables.  
tV Vit i ,, ,0

iiV V,0 0
tV Vt,0(1) 
(2) 
(3) 
(4) 
(5) 
tit
ii
VV t
t,


iit t V V,Measure of a General Nature No  0111 -OOP -C067 -16 
12 3 Technical requirements  
Technical requirements are based on the requirements of OIML  R 80-12. 
3.1 Kinds of measuring instruments  
Tanks are categorised according to the following criteria:  
a) volume measurement principle:  
 mechanical level measurement (one or more volume marks, gauge, measuring rod, or 
measuring strip), see Figures  2 and 3:  
 
 
Legend : 1 - tank dome, 2 - volume mark, 3 - sight -glass, 4 - tank 
Figure  2 - Tank with one (two opposed) mark(s) in the dome, or with an overflow (beer tank)  
Measure of a General Nature No  0111 -OOP -C067 -16 
13 
  
Legend : 1 - tank dome, 5 - measuring rod  
Figure  3 - Examples of tanks with a mechanical measuring rod in the dome  
 electronic level measurement (an electronic level indicator with a float/slider, ultrasound level 
indicator, radar/laser level indicator, other contactless measurement principle);  
 automatic volume measurement (can include complete automatic contro l and monitoring of 
delivery/receipt, inclusion of tilt influences, remaining amount, surface waves, etc.), see 
Figures  4 and 5.  
Measure of a General Nature No  0111 -OOP -C067 -16 
14  
Legend:0 - liquid remnant sensor, 1 - tank, 2 - electronic level indicator, 3 - float, 4 - liquid, 5 - foot 
valve, 6 - full/e mpty pipes, 7 - filling (dry) connector, 8 - collector, 9, 15, 16 - pipes, 10 - 
pump, 11 vapour separator, 12 - level indicator, 13 - vent valve, 14 - separator discharge 
valve, 17 - filter, 18 - measuring and control unit, 19 - pump bypass, 20 - empty hos e, 21 - 
temperature sensor, 22 - non-return valve, 23, 24, 25 - full-hose valve, 26 - empty -hose 
valve, 27 - full hose, 28 - alternative dry connector on right side, 29 - collector air purge 
valve, 30 - separator vent lock  
Figure  4 - An example of an autom atic measuring system with electronic level indicators for 
dispensing fuel  
Measure of a General Nature No  0111 -OOP -C067 -16 
15 
  
Legend:1 - electronic level indicator, 2 - tank, 3 - float, 4, 7 - chamber vent, 5 - remaining liquid sensor, 
6, 8, 9 - valve for pumping into trailer, 10 - non-return valve, 11 - transfer point sensor, 12 
- transfer point with sight -glass, 13 - pump, 14 - suction container, 15 - pressurised air 
valve, 16 - level sensor, 17 - vacuum valve, 18 - shut-off valve, 19 - milk sampling system, 
20 - pressure valve, 21 - main shut -off valve , 22 - temperature sensor, 23 - vacuum sensor, 
24 - suction hose, 25 - suction adapter, 26 - measuring and control unit  
Figure  5 - An example of an automatic measuring system with electronic level indicators for 
receiving milk  
b) connected equipment —the tank is/is not equipped with:  
 an installation for measuring partially delivered or received quantities;  
 an internal pump;  
 a distributor (collector);  
 an installation with a full hose;  
c) conditions of use (influencing factors):  
 according to pressure, atmospheric or  pressurised (e.g. liquefied gases or beer);  
 according to temperature, without heating, with/without insulation, with heating 
with/without insulation.  
d) nominal volume:  
 road tankers usually have a tank volume from 0.5  m3 to 50  m3; 
 rail tankers usually have a  tank volume from 10  m3 to 120  m3. 
e) tank mounting method:  
 directly and permanently on the frame of the vehicle, trailer  or semi -trailer, self -propelled, 
removable;  
Measure of a General Nature No  0111 -OOP -C067 -16 
16  temporarily on a vehicle with the use of equipment to ensure the tank remains fixed with 
respect to the vehicle.  
3.2 Tank design requirements  
If the tank is split into chambers, each chamber is considered to be a separate tank.  
The nominal volume of a tank or its chamber must be at least 500  litres.  
The shape and location of the tank or chamber, including filling and discharge equipment, must facilitate 
complete and quick emptying of the tank in all of its permitted positions.  
Complete emptying must be ensured:  
a) by appropriate tank shape;  
b) by the bottom generatrix of the tank having a gradient of at  least 2  % (1.2°) if the vehicle is in a 
horizontal position;  
c) in another manner.  
If it cannot be emptied completely in all positions expected during operation, a device must be used to 
facilitate complete emptying (e.g. an additional liquid sensor in the chamber and/or tilt monitoring).  
The measuring tank must have pads at least 500  mm long affixed to it to check normal position using 
an electronic level gauge.  
The emptying apparatus includes one or two outlet pipes (making it possible to empty the tanker on 
either side), each with a shut -off valve. The  flow of liquid between the tank and the outlet pipe can be 
stopped with a foot valve. If  the tank has two outlet pipes, an appropriate interlocking arrangement must 
prevent the simultaneous use of both outle t pipes. The  outlet pipe must be as short as possible and must 
have an appropriate gradient (at least 2  ° is recommended).There must be a liquid sensor or sight -glass 
at the lowest point of the outlet pipe (except for automatic measuring systems).  
For full -hose delivery, gas separators must be used, or existing equipment must operate so that the full 
hose is entirely filled when the level is being measured.  
A change from full to empty hose, or substitution of full -hose systems during a transaction is permis sible 
only if the filling levels in all chambers are monitored simultaneously.  
It must be possible to empty each chamber separately. The  tank may be equipped with a discharge 
distributor. A  distributor without automatic control must have an appropriate dev ice that will prevent 
discharge from one chamber to another. The  presence of the distributor must be specified in the 
certificate.  
Tanks intended for filling aircraft may have a device connected at their lowest point for decanting water 
and impurities. Thi s device has a separate small -diameter decanting pipe.  
Tanks must be tight and impermeable, resistant against deformations during transport, filling  and 
discharge. The  shell and bottom of the tank may be reinforced. Internal  reinforcements must not prevent  
the escape of gases during filling or complete emptying of the chamber.  
Nominal tank volume must not differ from the volume recorded in manufacturing documentation by 
more than 10  %. 
It is forbidden to place any dead space into the tank in order to change  its volume, or any other items 
that when removed or changed will change the tank volume.  
Beer tanks are pressure vessels. Each  chamber is equipped with a relief valve, a pressure sensor, a filling 
and discharge valve, an oval access port  and a graduated bell. The  air relief tube that leads into the 
graduated bell becomes the overflow edge, thus defining the measuring space.  
Fixed internal components (e.g. heating coils) inside the measuring chamber are allowed if they are 
present during measurement and the y cannot be modified or removed.  
The shape of the tank or chamber should be such that it quickly calms waves on the surface of the liquid.  Measure of a General Nature No  0111 -OOP -C067 -16 
17 
 In order to minimise the effects of tilting, tanks or chambers should be longitudinally and transversely 
symmetrical,  and level sensors should be centrally located. If  correct measurement is not possible in all 
positions expected during operation, the tank must be equipped with an apparatus to measure position 
relative to the reference position.  
 
Tilt - according to the ma nufacturer's specifications, a maximum of ±5° in the longitudinal 
and transverse direction  
- during delivery, the bottom of each chamber should have a gradient toward  the 
discharge opening (to the foot valve)  
 
Tanks with mechanical or electronic level measurement must include:  
a) a dome with reinforcing elements serving as an inspection opening and as an expansion space, 
and in some applications (not for fuels) to increase tank sensitivity. It  is located on top of the 
tank, if possible along its axis.  
The dome can include:  
 a filling opening connected with a tight closure;  
 a flange for monitoring filling;  
 a ventilation apparatus or a bi -directional safety valve.  
The level mark can be in the dome or in the upper part of the tank body in a manner that complies  
with sensitivity requirements. The  dome can be cylindrical or oval with vertical walls; a 
minimum diameter of 500  mm is recommended to facilitate tank or chamber inspection.  
b) tanks with mechanical level measurement must have a ladder to access the dome and  a platform 
for the individual performing tank measurement and inspection.  
c) tanks with electronic level measurement must:  
 prevent access to the tank interior with a seal or other means; or  
 must facilitate easy visual inspection pursuant to point  b). 
Tanks for the transport of hazardous liquids must also comply with other relevant regulations (for 
example protection against overfilling or protection against explosion; tanks for liquefied gases must 
not have domes, and are subject to regulations for the desig n of pressure vessels).  
Tanks for the transport of liquid foodstuffs must not affect the quality of the transported liquids (due to 
shape, material, etc.) and must also comply with other relevant regulations.  
Both of the above requirements must not influen ce the tank's measuring function.  
The measuring system may contain a sampling apparatus to determine the properties of the measured 
liquid.  
If the sampled amount is less than one -third the absolute value of the absolute value of the maximum 
permissible err or in row  B of Table  3 applied to the nominal volume of the tank or chamber, this quantity 
need not be included in measurement results.  
Exceeding the measurement range of the level sensor must be considered a defect.  
The level sensor may be equipped with a  baffle tube in order to calm waves on the surface. In  the area 
of the bottom, top, and in between, the tube must have openings for liquid exchange. The  tube must not 
influence measurement, for example due to the deposition of contaminants during normal operation.  
In the case of a level sensor with a float, the float must not change its mass or volume due to the measured 
liquid. Pressure  also must not aff ect its volume. The  cross -section of the float must be known to the 
extent of its submersion range. The  float shape must not lead to liquid retention, except for capillary 
action, nor to retention of gas or water underneath the float.  Measure of a General Nature No  0111 -OOP -C067 -16 
18 In the case of ultras ound level sensors, the effects of the properties of the measured liquid (density, 
modulus of elasticity) on signal passage time may be compensated using an appropriate method, for 
example reference marks.  
The measuring system may be equipped with addition al sensors (temperature, density, pH, etc.) whose 
measured values are used to calculate volume or provide information about the condition of the liquid.  
3.3 Conversion apparatus  
Supporting data for conversion (e.g. density under basic conditions, or therma l expansion coefficient) 
may either be set permanently or can be adjustable depending on the product. This  data must be protected 
from tampering.  
If data are adjustable, the indicator and if appropriate also the printout must clearly state which value 
was used, or which product was measured.  
The measurement method —with or without conversion due to the effect of temperature on volume —
for the given product must be selected during verification. Similarly , only one set of data may be entered 
for conversion for the given product.  
The reading of the indication must be reliable, easy  and unambiguous. The  customer must be able to 
check it without taking special measures. Display  of the quantity during the course of measurement is 
mandatory only in the case of direct  public sale.  
The type of quantity displayed (under measurement conditions or under basic conditions) must be clear.  
Indication resolution must be in the form (1, 2, or 5)  10n where n is a whole number that must not 
exceed one -tenth of the minimum nomina l volume deviation.  
In measurement mode, it must be possible to output all measured and calculated values, including 
supporting data. However , not all values need to be permanently displayed. The  measuring system can 
have various units to display the same measured amount.  
In the case of quantity conversion, the unconverted quantity must not be displayed during normal 
operation. However , the unconverted quantity must be available for test purposes.  
The unit price can be entered prior to or after delivery. It  is used to calculate the total price, which may 
be printed on the bill of delivery or on the invoice.  
A printer is required only for measuring systems for mineral oils and liquefied gas.  
If a bill of delivery is generated, it must contain at least the fol lowing information:  
 identification of the measuring system (e.g. serial number, vehicle number);  
 the name of the product or group of products;  
 the transaction number;  
 the volume under measurement conditions with the comment 'at delivery temperature' or the  
volume under basic conditions.  
If more than one chamber is used during the transaction for delivery/receipt, all results may be printed 
on the same bill of delivery. If  there is more than one data item for the same product, these items may 
be totalled.  
If the same printout contains information from a verified part of the system along with information from 
an unverified part of the system, the verified information must be preceded and followed by a special 
symbol (a star '*').This fact must be stated in the  measuring instrument's documentation or in another 
suitable location so that the user of the measuring instrument is informed in a sufficient manner.  
Measuring systems may have a recording device to store measured values prior to their use or the keep 
a record of the business transaction as proof in case of dispute. A  device for reading stored information 
is part of the recording device.  Measure of a General Nature No  0111 -OOP -C067 -16 
19 
 The recording medium must have sufficient permanency to protect data from damage under normal 
operating conditions. It  must not be possible to change stored data (intentionally or 
unintentionally).There must be sufficient memory for any planned use.  
Measuring systems that are not used for direct public sale may have data memory instead of a printer. 
In this case, all data r equired for a printout must be stored.  
Unless stipulated otherwise, measurement data must be stored at least until an invoice is issued and the 
deadline for any claims pursuant to applicable legislation has passed before it is deleted. If  the recording 
device is full and the stored data cannot be deleted because these periods have not yet expired, it must 
be impossible to commence additional measurement.  
If the measured data has been printed out or transmitted in a manner permitted for verification, it can be 
deleted.  
3.4 Fault prevention and measuring instrument security  
The critical change value for the measured volume of liquid is equal to the greater of the following 
values:  
a) one-fifth of the maximum permissible error corresponding to the measured quantit y; or 
b) the minimum nominal volume deviation.  
If the transaction is not interrupted due to a power failure, all measuring and control functions in the 
measuring system must function using a backup source during said power failure.  
If the transaction is inter rupted due to a power failure, data from the moment of interruption must be 
stored and displayed for a sufficient period so that this transaction can be completed. In  this case, the 
absolute value of the maximum permissible error increases to 5  % of the mi nimum delivery.  
A monitoring apparatus is used to detect faults that have an influence on the measured volume that 
exceeds the critical change value, and must have the following effect:  
a) it automatically corrects volume changes; or  
b) it takes out of service o nly the faulty equipment, while the measuring system continues in 
accordance with regulations without this equipment; or  
c) it stops the transaction.  
The monitoring apparatus is checked for proper operation, for example by:  
a) disconnecting the sensor; or  
b) interrupting the signal circuit; or  
c) disconnecting power supply.  
For measuring systems with level indicators, only a type  I and P monitoring apparatus is permitted. 
Type  I is a discontinuous monitoring apparatus that is active only at the start and end of e ach transaction, 
while type  P is a continuous monitoring apparatus that operates during the entire duration of the 
transaction.  
Monitoring apparatus for level sensors (type  P), temperature sensors (type  P), liquid sensors (type  I), 
and tilt sensors (type  I) must ensure the sensors are usable, operating correctly, transmitting data 
correctly, and if appropriate, also comply with the stipulated measurement range.  
A monitoring apparatus for values of permanently stored instructions and data and all procedures for 
internal transmission and storage of data concerning measured results must be of type  I or P.  
A monitoring apparatus for correct calculations must be of type  P. 
A monitoring apparatus for the display will make it possible to monitor the improper functi oning of 
individual elements, or automatic monitoring, or will prevent erroneous interpretation. Automatic  
detection can for example monitor the current between segments of LED displays, or measure the grid 
voltage of fluorescent displays. A  visual check i s performed for example using the black -white test.  Measure of a General Nature No  0111 -OOP -C067 -16 
20 A monitoring apparatus for connected equipment must check that it is usable, if needed, and validity of 
data transmission. A  printer monitoring apparatus must also check for the presence of paper.  
3.5 Pow er supply  
Measuring instruments that use an electronic conversion apparatus must have a power supply that is 
suited for the environment in which they are operated (for example in an explosive environment) 
pursuant to applicable legislation.  
Table  11 
Supply  voltage (1) (2)  (Unom −15 %) to ( Unom +10 %) 
Supply frequency (1)  (fnom −2 %) to ( fnom +2 %) 
Internal battery voltage (1)  the minimum voltage under which the device works properly according 
to specifications for voltage supplied by a new battery  
Road vehicle battery voltage (2)  12 V battery  9–16 V 
24 V battery  16–32 V 
Tilt according to manufacturer specifications  
(1) If applicable.  
(2) Values of Unom are provided on the measuring device. If  the range is specified, ' -15 %' corresponds to 
the lower value and '+10  %' corresponds to the upper value of the range.  
3.6 Resistance of the measuring instrument to external influences  
Measuring instruments are intended for measurement outdoors, i.e. climactic environment class  H3 (see 
also OIML  R 80-12). 
Measuring instruments are transported on vehicles —mechanical environment  M3 (see also OIML  R 80-
12). 
3.7 Electromagnetic environment  
For measuring instruments connected with electronic transducers and  a conversion apparatus, 
electromagnetic environment class E3 is defined (see also OIML  R 80-12). 
3.8 Measuring instrument security and fraud protection  
Measuring instruments must contain protective devices that may be sealed in such a way that after being  
sealed, before and after the measuring instrument has been correctly installed, there is no way it can be 
disassembled or modified without damaging the seal or protective devices.  
4 Measuring instrument labelling  
4.1 Markings on the measuring instrument  
Every tank must have a clearly visible and easily readable data plate. The  plate material must be resistant 
to the tank's operating conditions and must facilitate easy recording. The  plate must be affixed to the 
tank in a way that makes it impossible to rem ove without damaging the metrological seal.  
The data plate must bear the following information:  
a) the manufacturer’s name or mark;  
b) the tank's type and year of manufacture (the year may be part of the serial number);  Measure of a General Nature No  0111 -OOP -C067 -16 
21 
 c) the tank's serial number;  
d) the type and year of manufacture of the level indication system, if used;  
e) the serial number of the level indication system, if used;  
f) the type -approval mark;  
g) the nominal volume of the tank or of each chamber;  
h) the accuracy class, if other than 0.5;  
i) the minimum delivery o f the tank or of each chamber;  
j) the reference temperature, if other than + 15  °C; 
k) the type of liquid;  
l) the test and operating overpressure, or underpressure;  
m) the calibration method: SVL = with baffle or BVL = without baffle (if it can be dismounted);  
n) the tan k material type or the thermal expansion coefficient of the tank material;  
o) the type of protective interior coating, if used.  
If appropriate, empty space is left for the verification mark.  
4.2 Documentation  
Prior to initial verification, it is necessary to draw up measuring system documentation that must contain:  
a) all information on the data plate;  
b) a sealing plan;  
c) a schematic of the pipe system;  
d) a pneumatic schematic with metrologically important lines indicated;  
e) a printout of calibration parameters and calib ration tables, if used;  
f) the maximum diameter and maximum length of the full hose, if used;  
g) a special table with a description of changes to the measuring system, repairs, and any damage 
to official marks including their confirmation;  
h) the checksum of a prog ramme permissible for verification, and its parameters, if used.  
Measuring system documentation is part of the measuring system and must be kept in the cistern vehicle 
(tanker).  
4.3 Calibration plate  
Tanks with measuring rods with a scale in non -volume units can replace documentation with a 
calibration plate attached to the tank, with the following information:  
a) the name of the entity that calibrated the tank and created the calibration table;  
b) the certificate number;  
c) the reference temperature;  
d) the number of heating elements, if used;  
e) a calibration table (as a function of volume/height).  
4.4 Certificate  
A certificate for road tankers must contain the following information:  
a) the issuing authority and certificate number;  
b) the holder's name, and if applicable al so their address;  
c) the name or mark of the manufacturer, the type, year of manufacture, and serial number;  Measure of a General Nature No  0111 -OOP -C067 -16 
22 d) the vehicle's plate number, if applicable;  
e) the number of chambers and heating elements, if used;  
f) identification of the reference point and vertical ax is of measurement, if these are used;  
g) the method used;  
h) rules for filling outlet pipes, indication if a distributor is present;  
i) the uncertainty in determining volume values specified in the certificate;  
j) the date of issue and expiry date;  
k) the name and signat ure of a responsible individual;  
l) a diagram explaining symbols used;  
m) the height of the pivot during measurement (for trailers only);  
n) the number and location of verification marks.  
The certificate must contain the following information for each chamber:  
a) nominal volume;  
b) total volume;  
c) height of ullage from nominal volume;  
d) reference height.  
A certificate for rail tankers must contain the following information:  
a) the issuing authority and certificate number;  
b) the registration number of the rail tanker;  
c) the holde r's name, and if applicable also their address;  
d) the test method, place, and date;  
e) identification of the reference point and vertical axis of measurement;  
f) rules for filling the tank and outlet pipes;  
g) reference height;  
h) total volume and corresponding height of ullage;  
i) the reference temperature;  
j) the uncertainty in determining volume values specified in the certificate;  
k) the date of issue and expiry date of the certificate;  
l) the name and signature of a responsible individual;  
m) a diagram explaining symbols used;  
n) a calibration table in statutory units, the volume of liquid in the tank as a function of the height 
of ullage expressed in centimetres, within the range of level measurement;  
o) the number and location of verification marks.  
4.5 Placement of the official mark  
The tank must have prepared locations for attaching official marks. Official  mark placement is stipulated 
in the measuring instrument's type -approval certificate.  
The location of the main official mark is on the measuring instrument's data plate.  
All measuring systems must have official marks affixed in a way that prevents or indicates unauthorised 
tampering. The  following places are sealed (if used):  
a) the indication apparatus of the level gauge system;  
b) the control unit and interface;  
c) transducer box es including cables to measurement sensors (for example for temperature and the 
presence of liquid);  
d) tilt sensors;  Measure of a General Nature No  0111 -OOP -C067 -16 
23 
 e) temperature sensors;  
f) liquid sensors (except for those that removed during cleaning);  
g) measuring rods at their upper and lower attachment point s; 
h) a measuring system data plate, operating instructions, and a pneumatic and pipe diagram;  
i) lids on domes and chamber access ports for measuring systems that are filled only from the 
bottom;  
j) heating elements connected to the tank.  
No seals are applied to t he pipe system.  
Official mark placement must be designed so that sealing and an external inspection can take place 
without any obstructions. Official  mark placement is stipulated individually for each type in the type -
approval certificate.  
5 Type approval of the measuring instrument  
5.1 In general  
Transport tank measuring systems subject to metrological control are subject to all of the following 
operations:  
a) type approval;  
b) a preliminary test (if it contains electronic components);  
c) initial verification;  
d) subsequent verification.  
An application for type approval of a road or rail tanker must contain the following documents:  
a) a description of its technical characteristics and operating principle (including the level 
measurement system and connecting devices, if used);  
b) drawings depicting:  
 the entire road or rail tanker system;  
 the entire tank systems, including its chambers;  
 the entire system and function of the level gauge system;  
 auxiliary and additional devices, according to use;  
 details of the dome, reinforcem ents, and outlet devices;  
 a data plate;  
 the location of seals and official marks.  
The number of samples needed for type tests is determined by the entity performing the test.  
Type tests for road and rail tankers include the following operations in accordan ce with the relevant 
technical standard document (OIML)5, especially:  
a) an external inspection;  
b) a leakage test;  
c) a pressure test (the responsibility of the manufacturer, who submits test results), if needed. 
Figure  6 shows an example of a measuring system to determine the increase in tank volume due 
to internal pressure;  
d) a test of the tank's thermal expansion;  
e) a dimensional stability test (change of reference height for an empty/full chamber);  
                                                      
5 OIML  R 80-2 'Road and rail tankers with level gauging. Part  1:Metrological controls and tests' —CD1  Measure of a General Nature No  0111 -OOP -C067 -16 
24 f) test of volumetric stability during operation (the influence of adj acent chambers due to 
alternating filling and emptying);  
g) correct filling test;  
h) complete emptying test;  
i) calibration of the dependence of volume/level for individual chambers;  
j) test of sensitivity and expansion volume;  
k) test of connecting devices and tilt corr ection, if used;  
l) ullage test;  
m) evaluative tests of electronic parts (climactic —dry heat, cold, wet heat cyclically; vibration —
cyclically; electrical —changes in supply voltage, supply voltage dip, discharge, electrostatic 
discharge, electromagnetic sensitivi ty, defects in DC -powered devices).  
For tankers with electronic level measurement, safety class  I is used pursuant to the applicable 
technical standard (OIML)6; 
n) software is validated pursuant to the applicable technical standard: Welmec guide  7.27. 
 
 
Legend : 1 – tank, 2  – pressure sensor, 3  – hydraulic pump, 4, 5, 6  – valves, 7  – measuring container  
Figure  6 - Determining the increase in tank volume due to internal pressure  
The applicant must inform the approving authority of all changes and additions related to type approval. 
These  changes and additions are subject to additional type approval if they influence or could influence 
measurement results or the regulatory conditions of the measuring system's use. The  authority that 
approved the original type  will decide what tests will be performed to increase the scope of approval, 
depending on the type of changes.  
A preliminary test of the tank is performed using geometric, volumetric  or weight methods.  
The extended uncertainty ( k = 2) of the volume of liqu id in the tank must not exceed one -third of the 
maximum permissible error pursuant to Table  3, row  B. 
The preferred test liquid for calibration is water, or the liquid for which the measuring system is 
intended, or another suitable liquid with low thermal expansion, if possible. For  the weight method, a 
liquid with a sufficiently accurately measured or having a well -known density must be used.  
                                                      
6 OIML  D 11 General requirements for electronic measurin g instruments.  
7 WELMEC  7.2 Software Guide (Measuring Instruments Directive  2014/32/EU) The document is publicly 
available at www.welmec.org  
Measure of a General Nature No  0111 -OOP -C067 -16 
25 
 The test liquid for calibrating tanks intended for transport of beverages or food industry products must 
be hygieni cally clean and non -toxic.  
A preliminary test of temperature sensors is performed at a minimum of three points in the temperature 
range. Preferred  test temperatures are the minimum (or near 0  °C), reference  and maximum temperature.  
A preliminary test of ti lt sensors is performed for tilts of approximately ±5  ° in both directions 
(longitudinal and transverse), as well as for simultaneous tilts in both directions. Installation  direction 
must be specified on the sensor cabinet.  
A preliminary test of the volume  conversion apparatus must be performed for at least two points for 
each product or group of products used. Values  may come from actual measurement or may be 
simulated. Hardware  and software protection must be checked.  
A preliminary test of floats consists  of individual compensation of the submersion of each float with its 
own correction coefficient. This  coefficient is determined according to reference submersion of a 
reference float of the same type. The  diameter and weight of the float must be within tol erances specified 
in the type -approval certificate. No  official mark is placed on floats.  
A preliminary test of ultrasound level sensors is performed using a reference tube and a precisely defined 
reflective mark. The  permitted deviation is specified in th e type -approval certificate.  
A preliminary test of electronic measuring rods for a float system takes place using filling of various 
lengths. Permitted  deviations are specified in the type -approval certificate. Every  float measuring rod 
must have a documen t with its serial number, the speed of sound  and linearization  coefficients.  
A preliminary test of a measuring tube for ultrasound systems consists of a check of the physical 
dimensions of reference marks. Permitted  deviations are specified in the type -approval certificate.  
A preliminary test of the computer or control unit consists of a check whether the software (its modules) 
and its signatures are the same as the version specified in the type -approval certificate or its amendments. 
A check is performed to determine whether metrological data are protected (e.g. via an electronic seal).  
Unless specified otherwise, all parts subject to a preliminary test must have an official mark and be 
sealed if necessary.  
If all tests are passed and the requirements of this measure are complied with, a type -approval certificate 
is issued and the measuring instrument is issued a type -approval mark pursuant to special legislation8. 
5.2 Visual inspection  
The following is assessed during a visual inspecti on of a transport tank:  
 the external and internal appearance of the tank or chambers;  
 compliance with specifications in the type -approval certificate, including the version of software 
(modules) and its signatures, if used;  
 identification of parts used and  their preliminary test certificates, if they exist;  
 the validity and identification of calibration tables and tilt corrections, if they exist;  
 stored values of metrological parameters (e.g. float correction, product data, volume conversion 
mode, etc.);  
 the functionality of the measuring system;  
 measuring system documentation is valid and complete.  
                                                      
8 Decree of the Ministry of Industry and Trade No  262/2000, which provides uniformity and accuracy of 
measuring ins truments and measurements, as amended.  Measure of a General Nature No  0111 -OOP -C067 -16 
26 5.3 Functional tests  
a) leakage test —the tank or chamber, when filled up to the nominal volume mark, must not allow the 
test liquid to pass or to show any other sig ns of leakage;  
b) an expansion volume test;  
c) determination of ullage (in pipes for tanks);  
d) a check of the level sensor (interruption point —for level gauge systems);  
e) an accuracy test (except for tanks with one volume mark):  
 a test of volume measurement using a reference standard measuring container of volume between 
0.8 to 2  times the value of the minimum delivery. If  such a reference standard is not available, this 
quantity can be accumulated using n measurements. Prior  to commencing the test, the entire 
system  must be at least 90  % full. During  the last measurement until the chamber is emptied, the 
volume of pipes must be taken into account. For  each chamber, as many measurements are 
performed as the volume of the chamber allows. The  difference between the coun ter and the 
reference standard must not be greater than ±0.3  %.During measurement of residual emptying 
without a level gauge, the entire system must be entirely emptied.  
 a test of volume measurement using water by weight allows the optimum size of the test  
measurement for each chamber size to be determined. Prior  to commencing the test, the entire 
system must be at least 90  % full. The  difference between the counter and the reference standard 
must not be greater than ±0.3  %. 
 a test of volume measurement usi ng a flow reference standard, which must not have a deviation 
greater than 0.1  %.During measurement of one chamber, the temperature of the liquid must not 
change by more than ±3  °C. In order to minimise systematic error, the reference standard must 
operate  between 35  % and 70  % of maximum flow rate during all measurements.  
 calibration of pipe volume. The  discharge valve and foot valve are closed on a chamber filled with 
a measurable quantity of liquid. The  foot valve remains closed and the discharge valve i s opened. 
Once  the contents of the pipes have poured out and dripped out, the volume of liquid captured is 
measured either volumetrically or by weight (the current density needs to be measured).  
 a test of a level gauge system with a full hose (if built in).Prior to the test, the chamber is filled 
with 200  L of test liquid plus the volume of pipes and full hose.  Batches of 200  L dispensed. The 
permissible error is ±0.3  % of the minimum delivery, but not less than ±3  L. The test has ended 
when discharged b elow the lowest point of the pipe.  
 the extended uncertainty (k = 2) of the volume of liquid in the tank for initial verification must 
not exceed one -third of the maximum permissible error pursuant to Table  3. 
 determination of the minimum measured quantity for each chamber within the scope of 
calibration; the value of MMQ may be changed no later than during initial verification (e.g. if 
measurement results exceed permissible error).  
f) a test of connected devices;  
g) a tilt correction test:  
 the tilt correction tes t is performed at two levels, at about 25  % and at about 80  % of chamber 
volume. The  vehicle is first allowed to come to rest in a horizontal position, and then in four axial 
tilts. The  volume of the chambers is printed out in all positions. In  the horizon tal position, the 
position indicator must be within ±0.05°.Tilts must be greater than ±3°, and the other axis may be 
within ±0.5°.The corrected volume during tilt must not differ from the volume in the horizontal 
position by more than 0.3  % of the chamber' s minimum delivery.  
All parts of the level gauge system that influence metrological parameters are subject to preliminary 
testing. The  use of simulators must be authorised by the entity that performed the type tests.  
All test equipment used must have the r equired accuracy and must be traceable to national reference 
standards. Tests  and test equipment must be documented.  Measure of a General Nature No  0111 -OOP -C067 -16 
27 
 5.4 Tests of resistance of the conversion apparatus to environmental interference  
Of the tests specified below, those that are relevant to the design and conditions of intended use of the 
conversion apparatus are performed.  
5.4.1 Tests of resistance to climactic influences  
5.4.1.1 Test of resistance to limits of temperatures  
Resistance to limits of ambient temperatures are tested with the conversion apparatus switched on:  
a) using dry heat at a temperature of +55  °C for 2  h; 
b) using cold at a temperature of -25 °C for 2  h. 
After the stipulated amount of time has passed, an accuracy test is performed under the given 
temperature limit at three poi nts of the measurement interval. Measurement  errors must not exceed the 
maximum permissible errors specified in Table  3. 
5.4.1.2 Test of resistance to humidity  
Resistance to humidity is tested with the conversion apparatus switched off using cyclical wet heat over 
two 24 -hour cycles at a maximum temperature of +55  °C and relative humidity greater than 95  %. 
Once both cycles have been completed and operating conditions have been restored, measurement error 
must not exceed the maximum permissible error speci fied in Table  3. 
5.4.2. Vibration test (random)  
The apparatus is tested in three mutually perpendicular axes, attached in the normal manner and in a 
normal operating position, always for two minutes. Power  is switched off during the vibration.  
 overall freq uency range = (10 –150) Hz 
 overall RMS = 7  m·s-2 
 ASD  (10–20) Hz = 1  m2·s-3 
 ASD  (20–150) Hz = −3  dB/octave  
Once vibrations have ended, measurement errors must not exceed the maximum permissible errors 
specified in Table  3. 
5.4.3 Test of immunity to a radio -frequency radiated electromagnetic field  
Immunity to a radio -frequency radiated electromagnetic field is tested with the conversion apparatus 
switched on; inputs can be simulated.  
 
The electromagnetic field has the following properties:  
 10 V/m for the frequ ency range (26 –2 000) MHz  
 amplitude modulation 80  % with a 1  kHz frequency sine wave.  
Either no critical change will occur during interference, or the monitoring device must detect incorrect 
operation and in the case of a critical change, intervene in acco rdance with Article  3.4. 
5.4.4 Test of immunity to a radio -frequency conducted electromagnetic field  
Immunity to a radio -frequency conducted electromagnetic field is tested with the conversion apparatus 
switched on; inputs can be simulated. The  electromagn etic field has the following properties:  
 10 V for an amplitude of 50  Ω 
 frequency range (0.15 –80) MHz  Measure of a General Nature No  0111 -OOP -C067 -16 
28 Either no critical change will occur during interference, or the monitoring device must detect incorrect 
operation and in the case of a critical change, in tervene in accordance with Article  3.4. 
5.4.5 Test of immunity to electrostatic discharge  
Electrostatic discharge immunity shall be tested with the conversion apparatus switched on, preferably 
using a 6  kV contact discharge applied to the conductive surface of the measuring instrument or an 8  kV 
air discharge applied to coupling planes mounted in the vicinity of the measuring instrument.  
The test must be performed for at least one flow rate, and simulated input signals are permitted. Either  
no critica l change will occur during interference, or the monitoring device must detect incorrect 
operation and in the case of a critical change, intervene in accordance with Article  3.4. 
5.4.6 Test of immunity to a 50  Hz power frequency magnetic field  
Magnetic fiel d immunity is tested with the conversion apparatus switched on with a 50  Hz frequency, 
magnetic field measuring 30  A/m for a permanent field and 300  A/m for a transient magnetic field (1 to 
3 seconds).  
Either no critical change will occur during interferen ce, or the monitoring device must detect incorrect 
operation and in the case of a critical change, intervene in accordance with Article  3.4. 
5.4.7 Test of immunity to transients/surges on signal, data  and control lines  
Immunity to transients/surges is test ed with the conversion apparatus switched on, with a test voltage of 
±1 kV on signal terminals with a repetition frequency of 5  kHz. The  interference is applied to all of the 
measuring instrument's inputs and outputs, each time for at least 1  minute.  
The t est must be performed for at least one flow rate, and simulated input signals are permitted. Either  
no critical change will occur during interference, or the monitoring device must detect incorrect 
operation and in the case of a critical change, intervene in accordance with Article  3.4. 
5.4.8 Test of immunity to supply voltage limit values  
Immunity to supply voltage limit values shall be tested with the conversion apparatus switched on. For  
AC power its limits are given as ( Unom −15 %) and ( Unom +10 %), where Unom is the nominal supply 
voltage.  
Measurement errors at limit values must not exceed the maximum permissible errors specified in 
Table  3. 
5.4.9 Test of immunity to surges on mains power lines  
Interference consists of three positive and thr ee negative pulses. For  AC, the pulses must be applied 
synchronously with AC supply voltage at phase angles of 0°, 90°, 180°, and 270°.Voltage amplitude is 
1.0 kV for line -to-line and 2.0  kV for line -to-ground.  
The test must be performed for at least one f low rate, and simulated input signals are permitted. Either  
no critical change will occur after interference has ended, or the monitoring device must detect incorrect 
operation and in the case of a critical change, intervene in accordance with Article  3.4. 
5.4.10 Test of immunity to AC mains voltage dips, short interruptions  and slow voltage 
fluctuations  
Immunity to AC mains voltage dips, short interruptions and slow voltage fluctuations is tested with the 
conversion apparatus switched on, by applying the f ollowing voltage reductions to all power inputs:  
 100 % of Unom for 0.5  AC power period;  
 100 % of Unom for 1  AC power period;  
 60 % of Unom for 10  AC power periods;  
 30 % of Unom for 25  AC power periods;  Measure of a General Nature No  0111 -OOP -C067 -16 
29 
  20 % of Unom for 250  AC power periods;  
 100 % of Unom for 250  AC power periods.  
The test must be performed for at least one flow rate, and simulated input signals are permitted. Either  
no critical change will occur during interference, or the monitoring device must detect incorrect 
operation and in the case o f a critical change, intervene in accordance with Article  3.4. 
5.4.11 Immunity to electrical fast transients/pulse clusters on mains power lines  
Immunity to transients/pulse clusters is tested with the conversion apparatus switched on, with a test 
voltage of ±2  kV on signal terminals with a repetition frequency of 5  kHz. Interference  is applied for 
each amplitude and polarity for at least 1  minute.  
The test must be performed for at least one flow rate, and simulated input signals are permitted. Either  
no cr itical change will occur during interference, or the monitoring device must detect incorrect 
operation and in the case of a critical change, intervene in accordance with Article  3.4. 
5.4.12 Test of immunity to low internal battery voltage  
Immunity to low i nternal battery voltage is tested with the conversion apparatus switched on and in 
measurement mode. The  supply voltage is gradually reduced until the tested device stops operating 
correctly. This  is tested for all functions.  
Measurement errors at limit va lues must not exceed the maximum permissible errors specified in 
Table  3. 
5.4.13 Test of immunity to changes in vehicle battery voltage  
Immunity to supply voltage changes is tested with the conversion apparatus switched on. For  12 V 
supply voltage this is 9  V and 16  V, for 24  V supply voltage this is 16  V and 32  V. 
Measurement errors at limit values must not exceed the maximum permissible errors specified in 
Table  3. 
5.4.14 Test of immunity to transient electrical connections al ong power cables from the vehicle 
battery  
Immunity to transient connections is tested with the conversion apparatus switched on, with a test 
voltage pursuant to Table  12: 
Table  12 
Test pulses  Pulse voltage  Us 
Unom = 12 V Unom = 24 V 
2a (sudden power interruption in a parallel device)  +50 V +50 V 
2b (switching off of a DC motor) +10 V +20 V 
3a (result of switching processes)  -150 V -200 V 
3b (result of switching processes)  +100  V +200  V 
Simulated input signals are permitted. Either  no critical change will occur during interference (in case 
2b after interference has ended), or the monitoring device must detect incorrect operation and in the case 
of a critical change, intervene in accordance with Article  3.4. Measure of a General Nature No  0111 -OOP -C067 -16 
30 5.4.15 Test of immunity t o transient electrical connections through other than power cables from 
the vehicle battery  
Immunity to transient connections is tested with the conversion apparatus switched on, with a test 
voltage of:  
12 V 
battery  Pulse  a Us -60 In 
Pulse  b Us +40 In 
24 V 
battery  Pulse  a Us -80 In 
Pulse  b Us +80 In 
Simulated input signals are permitted. Either  no critical change will occur during interference, or the 
monitoring device must detect incorrect operation and in the case of a critical change, intervene in 
accordance with Article  3.4. 
6 Initial verification  
6.1 In general  
Initial verification of tanks  consists of the following operations (the application of individual items 
depends on the design of the specific tank type):  
a) visual inspection:  
 the external and internal appearance of the tank or chambers;  
 compliance with specifications in the type -approva l certificate, including the version of 
software (modules) and its signatures, if used;  
 identification of parts used and their preliminary test certificates, if they exist;  
 the validity and identification of calibration tables and tilt corrections, if they  exist;  
 stored values of metrological parameters (e.g. float correction, product data, volume 
conversion mode, etc.);  
 the functionality of the measuring system;  
 that measuring system documentation is valid and complete;  
b) leakage test —the tank or chamber, wh en filled up to the nominal volume mark, must not allow 
the test liquid to pass or to show any other signs of leakage;  
c) an expansion volume test;  
d) determination of ullage (in pipes for tanks);  
e) a check of the level sensor (interruption point —for level gauge systems);  
f) an accuracy test (except for tanks with one volume mark):  
 a test of volume measurement using a reference standard measuring container of volume 
between 0.8 to 2  times the value of the minimum delivery. If  such a reference standard is 
not availabl e, this quantity can be accumulated using n measurements. Prior  to commencing 
the test, the entire system must be at least 90  % full. During  the last measurement until the 
chamber is emptied, the volume of pipes must be taken into account. For  each chamber , as 
many measurements are performed as the volume of the chamber allows. The  difference 
between the counter and the reference standard must not be greater than ±0.3  %.During 
measurement of residual emptying without a level gauge, the entire system must be  entirely 
emptied.  Measure of a General Nature No  0111 -OOP -C067 -16 
31 
  a test of volume measurement using water by weight allows the optimum size of the test 
measurement for each chamber size to be determined. Prior  to commencing the test, the 
entire system must be at least 90  % full. The  difference between  the counter and the 
reference standard must not be greater than ±0.3  %. 
 a test of volume measurement using a flow reference standard, which must not have a 
deviation greater than 0.1  %.During measurement of one chamber, the temperature of the 
liquid must not change by more than ±3  °C. In order to minimise systematic error, the 
reference standard must operate between 35  % and 70  % of maximum flow rate during all 
measurements.  
 calibration of pipe volume. The  discharge valve and foot valve are closed on a cha mber 
filled with a measurable quantity of liquid. The  foot valve remains closed and the discharge 
valve is opened. Once  the contents of the pipes have poured out and dripped out, the volume 
of liquid captured is measured either volumetrically or by weight (the current density needs 
to be measured).  
 a test of a level gauge system with a full hose (if built in).Prior to the test, the chamber is 
filled with 200  L of test liquid + the volume of pipes and full hose.  Batches of 200  L 
dispensed. The permissible er ror is ±0.3  % of the minimum delivery, but not less than ±3  L. 
The test has ended when discharged below the lowest point of the pipe.  
 the extended uncertainty ( k = 2) of the volume of liquid in the tank for initial verification 
must not exceed one -third of  the maximum permissible error pursuant to Table  3. 
 determination of the minimum measured quantity for each chamber within the scope of 
calibration; the value of MMQ may be changed no later than during initial verification (e.g. 
if measurement results exce ed permissible error).  
g) a test of connected devices;  
h) a tilt correction test:  
 the tilt correction test is performed at two levels, at about 25  % and at about 80  % of 
chamber volume. The  vehicle is first allowed to come to rest in a horizontal position, and 
then in four axial tilts. The  volume of the chambers is printed out in all positions. In  the 
horizontal position, the position indicator must be within ±0.05°.Tilts must be greater than 
±3°, and the other axis may be within ±0.5°.The corrected volume during  tilt must not differ 
from the volume in the horizontal position by more than 0.3  % of the chamber's minimum 
delivery.  
All parts of the level gauge system that influence metrological parameters are subject to preliminary 
testing. The  use of simulators must be authorised by the entity that performed the type tests.  
All test equipment used must have the required accuracy and must be traceable to national reference 
standards. Tests  and test equipment must be documented.  
6.2 Evaluation of  tests  
The measuring instrument has passed if during testing it has complied with all requirements of Chapter  6 
of this Measure of a General Nature.  
7 Follow -up verification  
Subsequent verification of tanks consists of the following operations (the applica tion of individual items 
depends on the design of the specific tank type):  
a) visual inspection:  
 the external and internal appearance of the tank or chambers, extent/locations/degree of 
damage;  Measure of a General Nature No  0111 -OOP -C067 -16 
32  compliance with specifications in the type -approval certificate, including the version of 
software (modules) and its signatures, if used;  
 identification of parts used and their preliminary test certificates, if they have been repaired 
or replaced;  
 the validity and identification of calibration tables and tilt correction s, if they exist;  
 stored values of metrological parameters (e.g. float correction, product data, volume 
conversion mode, etc.);  
 the functionality of the measuring system;  
 measuring system documentation is valid and complete;  
b) accuracy test:  
 a test of volume  measurement using a reference standard measuring container of volume 
between 0.8 to 2  times the value of the minimum delivery. If  such a reference standard is 
not available, this quantity can be accumulated using n measurements.At least three 
measurements  are performed: an offtake in the upper range, an offtake in the middle range, 
and an offtake until completely empty.The difference between the counter and the reference 
standard must not be greater than ±0.5  % of the minimum measured quantity.  
 a test of v olume measurement using a flow reference standard, which must not have a 
deviation greater than 0.1  %.During measurement of one chamber, the temperature of the 
liquid must not change by more than ±3  °C. In order to minimise systematic error, the 
reference standard must operate between 35  % and 70  % of maximum flow rate during all 
measurements.  
 a test of a level gauge system with a full hose (if built in).Prior to the test, the chamber is 
filled with 200  L of test liquid + the volume of pipes and full hose. Batches  of 200  L 
dispensed. The permissible error is ±0.3  % of the minimum delivery, but not less than ±3  L. 
The test has ended when discharged below the lowest point of the pipe.  
 the extended uncertainty ( k = 2) of the volume of liquid in the tank for sub sequent 
verification must not exceed one -third of the maximum permissible error pursuant to 
Table  3. 
c) a test of connected devices;  
d) a tilt correction test:  
 the tilt correction test is performed at two levels, at about 25  % and at about 80  % of 
chamber volume . The  vehicle is first allowed to come to rest in a horizontal position, and 
then in four axial tilts. The  volume of the chambers is printed out in all positions. In  the 
horizontal position, the position indicator must be within ±0.05°.Tilts must be greate r than 
±3°, and the other axis may be within ±0.5°.The corrected volume during tilt must not differ 
from the volume in the horizontal position by more than 0.3  % of the chamber's minimum 
delivery.  
All test equipment used must have the required accuracy and  must be traceable to national reference 
standards. Tests  and test equipment must be documented.  
A tank or chamber with one volume mark is marked with the volume obtained through calibration, 
rounded down pursuant to Table  13. 
Table  13 
Accuracy class  0.2 0.3 0.5 1.0 
Calibrated chamber volume V in litres  Round down to litres  
V 1 500 0.5 1.0 2.0 5.0 Measure of a General Nature No  0111 -OOP -C067 -16 
33 
 1 500 V  5 000 1.0 2.0 5.0 10.0 
V 5 000 2.0 5.0 10.0 20.0 
 
A measuring instrument accuracy test is performed to determine whether the reading provided by the 
measuring instrument matches the volume within the maximum permissible error. The  measuring 
instrument's relative deviation is calculated according to the fo llowing relationship:  
 
where  Vn  ........   is the reading of the tested measuring instrument;  
 V  .........   is the true volume of liquid in the measuring instrument.  
 
7.1 Evaluation of tests  
The measuring instrument is suitable for verification purposes if  it passed all tests pursuant to this 
chapter.  
8 Measuring instrument check  
When checking measuring instruments pursuant to §  11a of the Metrology Act at the request of an entity 
that could be affected by its incorrect measurement, Chapter  7 of this Measur e of a General Nature is 
followed, except that the maximum permissible errors are doubled.  
9 Notified standards  
To specify metrological and technical requirements for measuring devices and to specify verification 
and type -approval test methods stemming fro m this Measure of a General Nature, the CMI notifies 
Czech technical standards, other technical standards or technical documents of international or foreign 
organisations or other technical documents containing detailed technical requirements (hereinafter 
'notified standards').The CMI shall publish a list of these notified standards attached to the relevant 
measures, together with the General Measure, in a manner accessible to the public (on www.cmi.cz ). 
Compliance with  notified standards or parts thereof is considered, to the extent and under the conditions 
stipulated by a general measure, to be compliance with the requirements stipulated by this measure to 
which these standards or parts thereof apply.  
Compliance with n otified standards is one way of demonstrating compliance with the requirements. 
These  requirements may also be met by using another technical solution guaranteeing an equivalent or 
higher level of protection of legitimate interests.  
 
II. 
GROUNDS  
Pursuant to § 14(1)(j) of the Metrology Act, the CMI has issued this Measure of a General Nature toward 
the implementation of §  6(2), §  9(1) and (9), and  § 11a(3) of the Metrology Act, defining metrological 
100VV Ven(6) Measure of a General Nature No  0111 -OOP -C067 -16 
34 and technical requirements for specified measuring instrum ents and tests for type approval and 
verification of specified measuring instruments —'liquid transport tanks'.  
Decree  No 345/2002 stipulating measuring instruments for mandatory verification and measuring 
instruments subject to type approval, as amended, classifies this type of measuring instrument as a 
measuring instrument subject to type approval and verification under item  1.3.5(c) in the Annex’s 'List 
of Specified Measuring Device Types'.  
This legislation (General Measure) will be notified in accordanc e with Directive  (EU)  2015/1535 of the 
European Parliament and of the Council of 9  September  2015 defining a procedure for the provision of 
information in the field of technical regulations and of rules on Information Society services.  
 
III. 
INSTRUCTIONS  
In accordance with §  172(l), in conjunction with §  39(l) CAP, the CMI has stipulated a time limit for 
comments of 30  days as of the date of posting on the official notice board. Comments  submitted after 
this time limit will not be considered.  
The persons co ncerned are hereby invited to comment on this draft Measure of a General Nature. With  
regard to the provisions of §  172(4) CAP, the comments shall be submitted in writing.  
In accordance with §  174(l) CAP in conjunction with §  37(l) CAP, it must be clear wh o is making the 
comments, which measure of a general nature they concern, how it contradicts legislation or how the 
measure of a general nature is inaccurate, and they must be signed by the person making them.  
The supporting documents for this draft Genera l Measure may be consulted at the Czech Metrology 
Institute, Legal Metrology Department, Okružní  31, 638  00 Brno, after making arrangements by 
telephone.  
This General Measure shall be posted for 15  days.  
 
 
 
 ...…………………………..............  
RNDr.  Pavel Klenovsk ý 
Director -General  
 
Person responsible for accuracy:  Mgr.  Tomáš Hendrych  
 
Posted on:  
Signature of the authorised person confirming posting:....................................................  
Removed on:  
Signature of the authorised person confirming removal:....................................................