C z e c h  M e t r o l o g y  I n s t i t u t e  
Okružní 31,  638 00  
Brno  
 
1. ------IND- 2010 0782 CZ - EN- ------ 20101224 --- --- PROJET 
 
The Czech Metrology Institute (CMI), as the competent local body for stipulating metrological and 
technical requirements for a specified measuring device and for the stipulation of test method s for type 
approval and for verification of a specified measuring device pursuant to Section 14(1) of Act No. 
505/1990 Coll., on Metrology, as amended, and pursuant to provisions of Section 172 et seq. of Act 
No. 500/2004 Coll., the Administrative Code, as  amended (hereinafter the "AC"), has on 30 July 2010 
commenced ex officio proceedings pursuant to Section 46 of the AC, and based on supporting doc u-
ments issues this:  
 
 
I. 
M E A S U R E  O F  A  G E N E R A L  N A T U R E  
number: 0111 -OOP -C013 -10 
reference  no. 0313/006/10/Pos.,  
publication date: 11. 10. 2010  
 
stipulating metrological and technical requirements for specified measuring devices, 
including test methods for verifying specified measuring devices:  
"laboratory alcoholmeters with increments smaller or equal to 0.2 %"  
 
1   Basic definitions  
For the purposes of this measure of a general nature, terminology and definitions contained in the 
VIM1) and the following apply:  
1.1   hydrometer with constant mass : a measuring device with constant mass whose dep th of imme r-
sion in the measured liquid determines its density or concentration of one of its comp onents  
NOTE   The hydrometer may or may not include a thermometer.  
1.2   laboratory alcoholmeter with increments smaller or equal to 0.2 % : a glass hydrometer with 
constant mass intended for the measurement of the ethanol fraction or volume concentr ation of ethanol 
in a mixture of water and ethanol under laboratory conditions  
2   Metrological requirements  
                                                      
1)   International  Vocabulary of Metrology - Basic and General Concepts and Associated Terms (VIM).  Measure of a General Nature No. 0111 -OOP -C013-10 
2 2.1   Stipulated service conditions  
The alcoholmeter must meet metrological requirements for service temperature range specified by the 
manufacturer. If the manufactu rer does not specify this, a service temperature range of 0  °C to +30  °C 
applies.  
Alcoholmeters must not be used to measure concentrations of:  
– 0 % vol. ethan ol at temperatures below 20  °C, and  
– 100 % vol. ethanol at temperatures above 20  °C 
where a spirit h ydrometer must be used.  
The reference temperature for testing alcoholmeters is 20  °C, reference pressure is normal atmospheric 
pressure.  
2.2   Measurement interval  
The measurement intervals of a laboratory alcoholmeter are specified by the manufacturer. If  they are 
not specified by the manufacturer, measurement intervals must be as follows:  
– (0 to 25) % vol., (24 to 45) % vol., (44 to 70) % vol., (68 to 88) % vol. with increments of 
0.2 % vol.  
– (87 to 100) % vol. with increments of 0.1  % vol.  
If the laborator y alcoholmeter includes a thermometer, its measurement interval must correspond to 
the service temperatures specified in Article 2.1.  
2.3    Maximum permissible error  
2.3.1     Maximum permissible alcoholmeter error  
The maximum permissible error of a labora tory alcoholmeter with a measurement interval below 88% 
vol. is ±  0.2%, and for a measurement range of (87 to 100) % vol., the maximum permissible error is 
0.1 % vol.  
2.3.2    Maximum permissible thermometer error  
The maximum permissible error of a thermome ter that is part of a laboratory alcoholmeter for general 
measurement is ±  0.5 °C. 
3   Technical requirements  
3.1   Alcoholmeter design  
A laboratory alcoholmeter is composed of a glass tube, which may have a built -in thermometer, and 
whose lower portion co ntains a conical or hemispherical weight. Connected to the upper part is a c y-
lindrical stem that is sealed at its upper end.  
The entire outside surface of the alcoholmeter must be symmetrical around its main axis. A circular 
cross -section must not exhibit any sudden changes, and transitions of all parts of the alcoholmeter 
must be smooth and rounded.  
The taper ratio of the stem must not exceed 0.1 mm per 100 mm. The maximum permissible deviation 
from circularity of any stem cross -section along the entire le ngth of the scale is 0.10 mm.  
The entire length of the alcoholmeter must not exceed 440 mm.  
No part of the alcoholmeter may contain any unattached material.  Measure of a General Nature No. 0111 -OOP -C013-10 
3 3.2    Alcoholmeter graduated scale  
An alcoholmeter may have only one graduated scale, which must f it tightly against the inside wall of 
the alcoholmeter casing, must not exhibit unevenness and must not be helically twisted. The graduated 
scale of the alcoholmeter must not have been damaged by flame during sealing of the stem.  
The graduated scale markin gs must be perpendicular to the axis of the alcoholmeter, parallel to each 
other, and clear. All alcoholmeter graduated scale markings must have the same thickness, which must 
be no more than 0.2 mm.  
If alcoholmeter graduated scale markings have differing lengths, then the length of short markings 
must be at least one fifth of the circumference of the stem, medium markings at least one third of the 
circumference of the stem, and long markings at least half of the circumference of the stem. All grad u-
ated sca le markings must be right -aligned along one imaginary perpendicular line.  
The entire length of the graduated scale must be (180  ± 10) mm. 
The highest graduated scale marking on the alcoholmeter must be at least 15 mm below the top of the 
stem, and the lowe st marking at least 5 mm above the location where the stem widens to meet the cy l-
inder.  
Alcoholmeters are calibrated to be read at the lowest part of the meniscus.  
To check that the alcoholmeter graduated scale is correctly located in the stem, the stem su rface must 
have a verification line that aligns with the highest numbered mark on the graduated scale.  
The mutual positioning of the alcoholmeter graduated scale and thermometer must be such that the 
values of both graduated scales can be read without turn ing the alcoholmeter, and the right ends of the 
alcoholmeter graduated scale lines must pass behind the profile of the stem.  
3.3   Alcoholmeter thermometer  
The capillary must be capable of withstanding an upper temperature limit of +50  °C or the upper limi t 
of the upper measurement limit of the thermometer's graduated scale in accordance with  Article 2.2 
plus 10  °C, whichever is greater.  
The divisions of the thermometer's graduated scale must be 0.5 C.  
The total length of the thermometer's graduated scale m ust be at least 55 mm.  
To check that the thermometer's graduated scale is attached correctly, a verification line is placed on 
the backside of the cylinder at the location of the reference temperature marking during thermometer 
calibration.  
3.4    Working position of the alcoholmeter  
The alcoholmeter must float in liquid with its vertical axis perpendicular to the surface. The deviation 
of the alcoholmeter's axis to the side from vertical when looking at the alcoholmeter's graduated scale 
must not be greate r than 1º 30´.  
When meeting the previous requirement, stability must also be maintained, where the alcoholmeter is 
deflected to the opposite side and then must return to its original position.  
3.5   Material  
The glass used in the manufacture of the alcohol meter must be transparent, colourless and must permit 
easy reading of the graduated scale.  
4   Markings  
4.1   Markings on the measuring device  
A laboratory alcoholmeter must be legibly and permanently marked with the following information:  Measure of a General Nature No. 0111 -OOP -C013-10 
4 – the manufacturer 's name or mark,  
– measuring device type,  
– serial number and date of manufacture,  
– unit of measurement (% vol. of ethanol),  
– reference temperature (20  °C), 
– the type of liquid for which the alcoholmeter is intended, e.g. ethanol with water,  
– how to read data (rea d at lowest point of meniscus),  
– type approval mark.  
4.2   Verification marks  
The verification mark is etched onto the backside of the body of the alcoholmeter below the stem a t-
tachment location.  
5    Type approval  
5.1   In general  
The approval process for the measuring device includes the following tests:  
a) external inspection,  
b) shape and dimension check,  
c) test for stability and that the axis of the stem of the alcoholmeter is perpendicular to the su r-
face of the liquid in which it is floating,  
d) alcoholmeter accu racy test,  
e) thermometer accuracy test.  
5.2   External inspection  
The following is assessed during an external inspection:  
a) that prescribed tec hnical documentation is complete, including the user manual,  
b) that metrological and technical characteristics specifi ed by the manufacturer in documentation 
conform to requirements of this regulation listed in sections 2 and 3,  
c) the appearance and completeness of information in accordance with  prescribed technical 
document ation. 
5.3    Alcoholmeter shape and dimension che ck 
The shape and surface of the alcoholmeter must not exhibit any sudden changes and transitions.  
The deviation from circularity and the taper of the alcoholmeter stem are checked at each marked 
point of the alcoholmeter's graduated scale with a micrometer  to an accuracy of ±  0.01 mm, and the 
deviation from circularity of any stem cross -section must not exceed values listed in Article 3.1.  
The total length of the alcoholmeter is measured with a length measurement device with an accuracy 
of ± 0.5 mm. 
The pre scribed dimensions of the alcoholmeter's graduated scale markings are checked with a length 
measurement device to an accuracy of 0.01 mm.  Measure of a General Nature No. 0111 -OOP -C013-10 
5 5.4   Functional tests  
5.4.1    Calibration solutions  
Calibration liquids are solutions of  
– finely refined alcohol and distilled water with a concentration of approximately 97% vol.,  or 
– finely refined alcohol and diethyl ether for densities of (780 to 810)  kg · m-3 and correspon d-
ing concentrations.  
Prior to testing, solutions must be tempered to laboratory temperature with  a maximum deviation of 
± 5 °C from the reference temperature, and temperature changes during measurement must not exceed 
± 0.5 °C · h-1. 
5.4.2    Test for stability and to ensure that the axis of the stem of the alcoholmeter is perpendic u-
lar to the su rface of the liquid in which it is floating  
The perpendicularity of the stem axis is tested by submerging the alcoholmeter into a suitable calibr a-
tion liquid up to the lower edge of the alcoholmeter's graduated scale. Using an angle template placed 
behind the a lcoholmeter, the deviations of the alcoholmeter's stem from vertical is determined. The 
projection of the outline of the stem is observed from a distance of at least 250 mm.  
The subsequent stability test is performed by tilting the alcoholmeter opposite to  its stem's lean angle.  
This test must meet the requirements of Article 3.4.  
5.4.3    Alcoholmeter accuracy test  
Prior to the test, the alcoholmeter and all necessary aids must be thoroughly degreased by dipping into 
chromic sulphuric acid for at least 30 m inutes, rinsing with running water and rinsing with distilled 
water.  
Accuracy is tested by comparing measured values of the tested alcoholmeter against the values of a 
reference alcoholmeter in calibration liquids for the given alcoholmeter measurement int erval in ac-
cordance with  Article 5.4.1.  
Measurement is performed at least three times for at least five points of the graduated scale.  
During the test, it is important to ensure that the alcoholmeter and thermometer (that is part of the test 
bath) are at l east 10 mm apart and away from the walls of the container with the calibration liquid.  
After the test, both the reference and tested alcoholmeters are rinsed with distilled water.  
The measurement error at each point of the graduated scale must not exceed t he maximum permissible 
error in accordance with  Article 2.3.1.  
5.4.4    Alcoholmeter thermometer accuracy test  
The accuracy of the thermometer (that is part of the alcoholmeter) is tested by comparing measured 
values of the tested thermometer with values of  a reference thermometer, for at least three points of the 
scale: at the alcoholmeter's reference temperature and at both endpoints of the thermometer's scale.  
The measurement error at each point of the graduated scale must not exceed the maximum permissib le 
error in accordance with  Article 2.3.2.  
6   Initial verification  
6.1   In general  
The following is performed during initial verification:  
a) external inspection,  Measure of a General Nature No. 0111 -OOP -C013-10 
6 b) shape and dimension check,  
c) test for stability and that the axis of the stem of the alcoholmete r is perpendicular to the su r-
face of the liquid in which it is floating,  
d) alcoholmeter accuracy test,  
e) thermometer accuracy test.  
6.2   Visual inspection  
The following is assessed during visual inspection of laboratory alcoholmeters:  
a) that the measuring devic e is the same as the approved type;  
b) appearance (including description) and condition of the measuring device.  
6.3    Alcoholmeter shape and dimension check  
Shape and dimensions of the alcoholmeter are checked in accordance with  Article 5.3.  
6.4   Functiona l tests  
6.4.1    Test for stability and to ensure that the axis of the stem of the alcoholmeter is perpendic u-
lar to the su rface of the liquid in which it is floating  
The test for stability and to ensure that the axis of the stem of the alcoholmeter is perpe ndicular to the 
surface of the liquid in which it is floating is performed in accordance with  Article 5.4.2.  
6.4.2    Alcoholmeter accuracy test  
The alcoholmeter accuracy test is performed in accordance with  Article 5.4.3.  
6.4.3    Alcoholmeter thermometer a ccuracy test  
The accuracy test of the thermometer as part of the alcoholmeter is performed in accordance with  Ar-
ticle 5.4.4.  
7   Subsequent verification  
These measuring devices are not subject to subsequent verification.  
8   Notified standards  
To specify m etrological and technical requirements for measuring devices and to specify verific ation 
test methods stemming from this measure of a general nature, the CMI notifies Czech technical sta n-
dards, other technical standards or technical documents of internatio nal or foreign organizations or 
other technical documents containing detailed technical requirements (hereinafter "notified sta n-
dards"). The CMI shall publish a list of these notified standards, with their assignation to relevant 
measures, along with the m easure of a general nature, in a manner available to the public (on the we b-
site www.cmi.cz).  
Compliance with notified standards or parts thereof is considered to be, to the extent and under the 
conditions stipulated by a measure of a general nature, to be compliance with those requirements 
stipulated by this measure to which these standards or parts thereof apply.  
 
 
II. 
J U S T I F I C A T I O N  Measure of a General Nature No. 0111 -OOP -C013-10 
7 The CMI issues, towards the implementation of Section 24c of Act No. 505/1990 Coll., on metrology, 
as amended, th is measure of a general nature, stipulating metrological and technical requirements for 
specified measuring devices and test methods for verification of these specified measuring devices.  
In Decree No. 345/2002 Coll., specif ying measuring devices for manda tory verification and measuring 
devices subject to type approval, as amended, the annex "List of Specified Measuring Device Types" 
classifies " laboratory alcoholmeters with increments smaller or equal to 0.2 %"  under item 7.1.2 as 
measuring devices subject  to type approval and verific ation. 
The CMI thus issues, towards the implementation of Section 24c of Act No. 505/1990 Coll., on m e-
trology, as amended, for the measuring device type specified as " laboratory alcoholmeters with incr e-
ments smaller or equal to  0.2 %" , this measure of a general nature, stipulating metrological and techn i-
cal requirements for  laboratory alcoholmeters with increments smaller or equal to 0.2 %  and test 
methods for type approval and verification of these specified measuring d evices.  
III. 
N O T I C E  
A measure of a general nature cannot be appealed (Section 173 (2) of Act No. 500/2004 Coll., the 
Administrative Code, as amended (hereinafter the "Administrative Code").  
Pursuant to provisions of Section 172 (5) of the Administrative Code,  a decision on objections cannot 
be appealed in any manner.  
The conformance of a measure of a general nature with legislation can be assessed in review procee d-
ings pursuant to Section 94 to 96 of the Administrative Code. A participant may submit a request for a 
review to the administrative body that issued this measure of a general nature. If the administrative 
body does not find reasons for commencing review proceedings, it shall notify the applicant within 
thirty days of this fact along with its reasons. A decision on commencement of review proceedings 
can, in accordance with  Section 174 (2) of the Administrative Code, be issued within three years of the 
effective date of the measure of a general nature.  
 
 
 
IV. 
E F F E C T I V E  D  A T E  
This measure of a general nature takes effect on the fifteenth day following the day of its publication 
(Section 24d of Act No. 505/1990 Coll., on metrology, as amended).  
This measure of a general nature shall be published for a period of 15 days.