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 0773 CZ - EN- ------ 20101223 --- --- 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 su pporting 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 -C014 -10 
referen ce no. 0313/007/10/Pos.,  
publication date: 11 October 2010  
 
stipulating metrological and technical requirements for specified measuring devices, 
including test methods for verifying specified measuring devices:  
"laboratory saccharometers with increments of  0.1 %" 
 
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 depth 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 saccharometer with increments of 0.1 % : a glass hydrometer with constant mass 
intended for the measurement of the content by weight of sucrose in aqueous solutions or sugar in 
brewing malt under laboratory conditions.  
                                                      
1)   International Vocabulary of Metrology - Basic and General Concepts and Associated Terms (VIM).  Measure of a General Nature No. 0111 -OOP -C014-10 
2 2   Metrological requirements  
2.1   Stipulated service conditions  
The saccharometer must meet metrological requirements for service temperature range specified by 
the manufacturer. If the manufacturer does not specify this , a service temperature range of +10  °C to 
+50 °C applies.  
The reference temperature for testing saccharometers is 20  °C, reference pressure is normal atmo s-
pheric pressure.  
2.2   Measurement interval  
The measurement interval of a laboratory saccharometer f or measuring content by weight between 0% 
and 25% is specified by the manufacturer. If it is not specified by the manufacturer, measurement i n-
tervals with increments of 0.1% must be as follows:  
(0 to 6) % wt., (0 to 10) % wt., (5 to 17) % wt., (15 to 26) %  wt., (20 to 25) % wt., (10  to 25) % 
wt. 
If the laboratory saccharometer 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 sac charometer error  
The maximum permissible error of a laboratory saccharometer is ±  0.1 % vol.  
2.3.2    Maximum permissible thermometer error  
The maximum permissible error of a thermometer that is part of a laboratory saccharometer is 
± 0.5 °C. 
3   Technical requirements  
3.1   Saccharometer design  
A laboratory saccharometer is composed of a glass tube, which may have a built -in thermometer, and 
whose lower portion contains a conical or hemispherical weight. Connected to the upper part is a c y-
lindrical stem tha t is sealed at its upper end.  
The entire outside surface of the saccharometer must be symmetrical around its main axis. A circular 
cross -section must not exhibit any sudden changes, and transitions of all parts of the saccharometer 
must be smooth and round ed. 
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 length of the scale is 0.10 mm.  
The total length of the saccharometer and the length of the gr aduated scale must meet the requirements 
of Table 1.  
Table  1 – Laboratory saccharometer measurement interval requirements  
Measurement interval  % vol.  0 to 6  0 to 10  5 to 17  15 to 26  20 to 25  10 to 25  
Length of the graduated scale  mm 110±  10 160±  10 90± 10 170±  10 
Total saccharometer length  mm 380 440 360 440 
No part of the saccharometer may contain any unattached material.  Measure of a General Nature No. 0111 -OOP -C014-10 
3 3.2   Saccharometer graduated scale  
A saccharometer may have only one graduated scale, which must fit tightly against the inside wall  of 
the saccharometer casing, must not exhibit unevenness and must not be helically twisted. The grad u-
ated scale of the saccharometer must not have been damaged by flame during sealing of the stem.  
The graduated scale markings must be perpendicular to the axis of the saccharometer, parallel to each 
other, and clear. All saccharometer graduated scale markings must have the same thickness, which 
must be no more than 0.2 mm.  
If saccharometer graduated scale markings have differing lengths, then the length of s hort 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 scale markings must be right -aligned along one imaginary perpendicular line.  
The highest graduated scale marking on the saccharometer must be at least 15 mm below the top of the 
stem, and the lowest marking at least 5 mm above the location where the stem widens to meet the cy l-
inder.  
Sacc harometers are calibrated to be read at the upper edge of the meniscus.  
To check that the saccharometer graduated scale is correctly located in the stem, the stem surface must 
have a verification line that aligns with the highest numbered mark on the gradu ated scale.  
The mutual positioning of the saccharometer graduated scale and thermometer must be such that the 
values of both graduated scales can be read without turning the saccharometer, and the right ends of 
the saccharometer graduated scale lines must pass behind the profile of the stem.  
3.3   Saccharometer thermometer  
The capillary must be capable of withstanding an upper temperature limit of +50  °C or the upper limit 
of the upper measurement limit of the thermometer's graduated scale according to Arti cle 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 must be at least 60 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 saccharometer 
assessment.  
3.4   Working position of the saccharometer  
The saccharometer must float in liquid with its vertical axis p erpendicular to the surface. The deviation 
of the saccharometer's axis to the side from vertical when looking at the saccharometer's graduated 
scale must not be greater than 1º 30´.  
When meeting the previous requirement, stability must also be maintained, where the saccharometer is 
deflected to the opposite side and then must return to its original position.  
3.5   Material  
The glass used in the manufacture of saccharometers must be transparent, colourless and must permit 
easy reading of the graduated scale.  
4   Markings  
4.1   Markings on the measuring device  
A laboratory saccharometer must be legibly and permanently marked with the following information:  
– the manufacturer's name or mark,  Measure of a General Nature No. 0111 -OOP -C014-10 
4 – measuring device type,  
– serial number and date of manufacture,  
– unit of me asurement (%);  
– reference temperature (20  °C), 
– the type of liquid for which the saccharometer is intended (sucrose with water or wort and 
beer),  
– how to read data (read at upper edge of meniscus),  
– type approval mark.  
4.2   Verification mark  
The verification mark is etched onto the backside of the body of the saccharometer below the stem 
attachment location.  
5   Type approval  
5.1   In general  
The type approval process for the measuring device includes the following tests:  
a) external inspection,  
b) shape and dimensi on check,  
c) test for stability and that the axis of the stem of the saccharometer is perpendicular to the su r-
face of the liquid in which it is floating,  
d) saccharometer accuracy test,  
e) thermometer accuracy test.  
5.2   External inspection  
The following is assess ed during an external inspection:  
a) that prescribed tec hnical documentation is complete, including the user manual,  
b) that metrological and technical characteristics specified by the manufacturer in documentation 
conform to requirements of this regulation list ed in sections 2 and 3,  
c) the appearance and completeness of information in accordance with  prescribed technical 
document ation. 
5.3   Saccharometer shape and dimension check  
The shape and surface of the saccharometer must not exhibit any sudden changes and t ransitions.  
The deviation from circularity and the taper of the saccharometer stem are checked at each marked 
point of the saccharometer'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 saccharometer is measured with a length measurement device with an accuracy 
of ± 0.5 mm. 
The prescribed dimensions of the saccharometer'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 -C014-10 
5 5.4   Functional tests  
5.4.1    Assessment solutions  
The assessment liquid is a solution of 96% vol. sulphuric acid and 80% vol. finely refined alcohol. 
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 saccharometer is perpe n-
dicular to the su rface of the liquid in which it is floating  
The perpendicularity of the stem axis is tested by submerging the saccharometer into a suitable a s-
sessment liquid up to the lower edge of the saccharometer's graduated scale. Using an angle  template 
placed behind the saccharometer, the deviation of the saccharometer's stem from vertical is dete r-
mined. 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 tiltin g the saccharometer opposite to its stem's lean angle.  
This test must meet the requirements of Article 3.4.  
5.4.3    Saccharometer accuracy test  
Prior to the test, the saccharometer and all necessary aids must be thoroughly degreased by dipping 
into chromic  sulphuric acid for at least 30 minutes, rinsing with running water and rinsing with di s-
tilled water.  
Accuracy is tested by comparing measured values of the tested saccharometer against the values of a 
reference saccharometer in assessment liquids for the given saccharometer measurement interval in 
accordance 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 saccharometer and thermometer (tha t is part of the 
test bath) are at least 10 mm apart and away from the walls of the container with the assessment liquid.  
After the test, both the reference and tested saccharometers are rinsed with distilled water.  
The measurement error at each point of t he graduated scale must not exceed the maximum permissible 
error in accordance with  Article 2.3.1.  
5.4.4    Saccharometer thermometer accuracy test  
The accuracy of the thermometer (that is part of the saccharometer) 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 saccharometer's reference temperature and at both endpoints of the thermometer's scale.  
The measurement error at each point of the graduated scal e must not exceed the maximum permissible 
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,  
b) shape and dimension check,  
c) test for stability and to en sure that the axis of the stem of the saccharometer is perpendicular to 
the surface of the liquid in which it is floating,  
d) saccharometer accuracy test,  Measure of a General Nature No. 0111 -OOP -C014-10 
6 e) thermometer accuracy test.  
6.2   Visual inspection  
The following is assessed during visual inspection of  laboratory saccharometers:  
a) that the measuring device is the same as the approved type;  
b) appearance (including description) and condition of the measuring device.  
6.3   Saccharometer shape and dimension check  
Shape and dimensions of the saccharometer are ch ecked in accordance with  Article 5.3.  
6.4   Functional tests  
6.4.1    Test for stability and to ensure that the axis of the stem of the saccharometer is perpe n-
dicular to the su rface of the liquid in which it is floating  
The test for stability and that the a xis of the stem of the saccharometer is perpendicular to the su rface 
of the liquid in which it is floating is performed in accordance with  Article 5.4.2.  
6.4.2    Saccharometer accuracy test  
The saccharometer accuracy test is performed in accordance with  Article 5.4.3.  
6.4.3    Saccharometer thermometer accuracy test  
The accuracy test of the thermometer as part of the saccharometer is performed in accordance with  
Article 5.4.4.  
7   Subsequent verification  
These measuring devices are not subject to subsequent verification.  
8   Notified standards  
To specify metrological 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 technic al standards or technical documents of international 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 a ssignation to relevant 
measures, along with the measure 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 st ipulated 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  
The CMI issues, towards the implementation of Section 24c of Act  No. 505/1990 Coll., on metrology, 
as amended, this measure of a general nature, stipulating metrological and technical requirements for 
specified measuring devices and test methods for verification of these specified measuring devices.  Measure of a General Nature No. 0111 -OOP -C014-10 
7 In Decree No. 345/2 002 Coll., specif ying measuring devices for mandatory verification and measuring 
devices subject to type approval, as amended, the annex "List of Specified Measuring Device Types" 
classifies " laboratory saccharometers with increments of 0.1 %"  under item 7 .1.3 as measuring d evices 
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 saccharometers w ith in-
crements of 0.1 %" , this measure of a general nature, stipulating metrological and technical requir e-
ments for  laboratory saccharometers with increments of 0.1 %  and test methods for type a pproval 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 Co de, 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 reque st 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 reason s. 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.