FINAL DRAFT  UGANDA 
STANDARD  
  FDUS 1042  
First Edition  
2013 -mm-dd 
 
 
 Refer ence number  
FDUS 1042 : 2013 
© UNBS 2013   
  
Alcoholometers and alcohol hydrometer and thermometers for 
use in alcoholometry — Specification  
 FDUS 1042 : 2013  
ii © UNBS 2013  – All rights reserved  
 Compliance with this standard does not, of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provision s of a contract. Users are 
responsible for its correct application  
© UNBS 2013  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, including phot ocopying and microfilm, without prior written 
permission from UNBS.  
Requests for permission to reproduce this document should be addressed to  
The Executive Director  
Uganda National Bureau of Standards  
P.O. Box 6329  
Kampala  
Uganda  
Tel: 256 41 4 505 995  
Fax: 256 41 4 286 123  
E-mail: unbs@infocom.co.ug  
Web: www.unbs.go.ug  
 
. FDUS 1042 :2013  
© UNBS 2013  – All rights reserved  iii 
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Trade, Industry and Co -
operatives established under Cap 3 27, of the Laws of Uganda.  UNBS is mandated to co -ordinate the 
elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agreements of the World Trade Organisation (WTO).  
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a given field or are a and consists of representatives of 
consumers, traders, academicians, manufacturers, government and other stakeholders.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the 
general public for comments. Th e committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
This Final Draft Uganda S tandard is based on OIML R 44 Alcoholometers and alcohol hydrometers and 
thermometers for use in alcoholometry . 
Committee membership  
The following organizations are  represented on the Metrology  standards Technic al Committee (UNBS/TC 9), 
during the development of this standard:  
 Civil Aviation Authority.  
 Kampala City Traders Association  
 Kyambogo University Kampala  
 Makerere University Kampala  
 Ministry of Defense  
 Ministry of Energy  
 Ministry of Internal Affairs  
 Minist ry of Works and Transport  
 National Environmental Management Authority  
 Uganda National Bureau of Standards  
 UMEME  
 Uganda Alcohol Industry Association . 
 
. 
 FINAL DRAFT UGANDA STANDARD  FDUS 1042 : 2013  
 
© UNBS 2013 – All rights reserved  1 
 Alcoholometers and alcohol hydrometers and thermometers for 
use in alcoholometry  — Specification  
1 Scope 
This Final Draft Uganda Standards specifi es the requirements for  alcoholometers and alcohol hydrometers 
used for the determination of the alcoholic strength of mixtures of water and ethanol, and to thermometers for 
use in alcoholometry. It sets out tech nical and metrological specifications for these instruments, in accordance 
with International Alcoholometric Tables . 
This standard  covers  
a) glass hydrometers indicating percentage alcoholic strength by mass, referred to as  mass 
alcoholometers ,  
b) glass hydrom eters indicating percentage alcoholic strength by volume, referred to as volume 
alcoholometers, and  
c) glass hydrometers indicating density in kilogram per cubic metre, referred to as  alcohol hydrometers.  
NOTE 1  These instruments are graduated at a reference  temperature of 20 °C, in accordance with the International 
Alcoholometric Tables published by the International Organization of Legal Metrology . 
NOTE 2  These instruments are graduated for readings taken at the level of the free horizontal surface of the l iquid . 
2 Description  
2.1 The alcoholometers and alcohol hydrometers comprise : 
a) a cylindrical glass body, the bottom of which is conical or hemispherical, so that air bubbles are not 
trapped,  and 
b) a hollow cylindrical stem, fused to the upper part of the body , with its upper end closed.  
2.2 The entire external surface of the instrument shall be symmetrical about its main axis. The cross -
section shall not have any abrupt variation.  
2.3 The lower part of the body contains the loading material, the purpose of whi ch is to adjust the mass of 
the instrument.  
2.4 The stem carries a scale marked on a cylindrical support, which is permanently fixed to the inside of the  
stem . FDUS 1042 : 2013  
2 © UNBS 2013 – All rights reserved  
 3 Requirements  
3.1 Construction  
3.1.1 The glass used for the manufacture of the alcoholometers a nd alcohol hydrometers shall be 
transparent, and free from any defect liable to interfere with the reading of the indications. The glass shall 
have a coefficient of cubic expansion of (25 ± 2) 10 – 6 °C–1. 
3.1.2 The loading material shall be fixed in the b ottom of the body. If the loading material is solid, it shall not 
soften when raised to a temperature of 80 °C. There shall be no loose material in the other parts of the 
instrument.  
3.1.3 The instrument shall float with its stem in an approximately vertic al position. The maximum 
permissible angle between the stem and the vertical is 1.5° . 
3.2 Scale  
3.2.1 The alcoholometers and alcohol hydrometers shall have only one hydrometric scale.  
3.2.2 The scale and the inscriptions shall be marked on a support having  a smooth matt surface. This 
support shall be held rigidly in place in the stem, and means shall be provided to indicate any displacement of 
the scale and the scale support with respect to the stem. The support, scale and inscriptions shall show no 
trace o f distorsion, discolouration or charring, when maintained at a temperature of 70 °C for 24 h.  
3.2.3 The scale marks shall be lines  
a) situated in planes perpendicular to the axis of the instrument,  
b) black and marked clearly and indelibly,  and 
c) fine, clear -cut a nd of a uniform thickness, not exceeding 0.2 mm.  
3.2.4 The length of the short lines on the scale shall be at least one fifth of the stem circumference. The 
length of medium lines shall be at least one third of the stem circumference, and that of the long lines, at least 
half of the stem circumference.  
3.2.5 The nominal scale range for a mass or volume alcoholometer shall not exceed 10 %. The scale 
interval shall be 0.1 %. Each scale shall have from 5 to 10 additional divisions beyond its upper and lower 
nominal range limits.  
3.2.6 The nominal scale range for an alcohol hydrometer shall not exceed 20 kg/m3. The scale interval shall 
be 0.2 kg/m3. Each scale shall have from 5 to 10 additional divisions beyond its upper and lower nominal 
range limits. However, the scale need not extend beyond 1 000 kg/m3 
NOTE  Outside the nominal range of the scale, the lines may be of a different colour  
3.3 Graduation and numbering  
3.3.1 On alcoholometers, every tenth scale mark, counting from one end of the nominal scale, shall  be a 
long line. There shall be a medium line between two consecutive long lines, and four short lines between a 
long line and a medium line. Only the long lines shall be numbered.  
3.3.2 On alcohol hydrometers, every fifth line, counting from one end of th e nominal scale, shall be a long 
line. There shall be four short lines between two consecutive long lines. Only every fifth or tenth long line shall 
be numbered.  
3.3.3 The lines indicating the limits of the nominal scale shall be numbered in full. On alcoh ol hydrometers, 
the other numbers may be abbreviated.  FDUS 1042 : 2013 
© UNBS 2013 – All rights reserved  3 
 4 Classification and principal dimensions  
4.1 The alcoholometers and alcohol hydrometers belong to one of the accuracy classes, class I , class II or 
class III for which the maximum permissible errors ar e specified in 6.1. 
4.2 For class I instruments  
a) the mean scale spacing shall not be less than 1.5 mm,  and 
b) the outside stem diameter shall not be less than 3 mm.  
Instruments in this class shall not incorporate a thermometer.  
4.3 For class II instruments  
a) the mean scale spacing shall not be less than 1.05 mm,  and 
b) the outside stem diameter shall not be less than 3 mm.  
Instruments in this class may incorporate a thermometer.  
4.4 For class III instruments  
a) the mean scale spacing shall not be less than 0.85 mm,  and 
b) the outside stem diameter shall not be less than 2.5 mm.  
Instruments in this class may incorporate a thermometer.  
4.5 The external diameter of the body of any instrument shall be between 19  mm and 40 mm. The stem 
shall extend at least 15 mm above the hi ghest scale mark. The cross -section of the stem shall be uniform for 
at least 5 mm below the lowest scale mark . 
5 Marking  
5.1 The following inscriptions shall be legibly and indelibly marked inside the alcoholometers and alcohol 
hydrometers : 
 class I or cla ss II or class III ; 
 kg/m3 or % vol or % mass ; 
 20 °C ; 
 ethanol ; 
 name or identification mark of the manufacturer ; 
 identification number of the instrument ; and  
 pattern approval sign (when appropriate ). 
5.2 Indication of the mass of the instrument is optional. Where this information is given, the mass shall be 
expressed in milligrams, and marked on the external surface of the body . 
 FDUS 1042 : 2013  
4 © UNBS 2013 – All rights reserved  
 6 Maximum permissible errors  and verification  
6.1 The maximum permissible errors for alcoholometers and alcohol hydrometers, positi ve or negative, 
shall be:  
a) for class I instruments, one half scale interval ; and  
b) for class II and class III instruments, one scale interval . 
6.2 Verification shall be carried out at a minimum of three different points, distributed over the full nominal 
scale range.  
6.3 A space, for the verification mark, shall be left on the back of alcoholometers and alcohol hydrometers, 
within the upper third of the body . 
7 Thermometers used for the determination of the alcoholic strength  
7.1 Thermometers incorporated in t he instrument used to determine the alcoholic strength  
7.1.1  If the instrument used for determining the alcoholic strength belongs to class II or III, a thermometer of 
the liquid -in-glass, mercury filled type, may be incorporated in it.  
7.1.2 The thermomet er shall be graduated to 0.1 °C, 0.2 °C or 0.5 °C. It need not have a scale mark at 0 
°C. 
7.1.3 The minimum scale spacing shall be 0.8 mm for thermometers graduated to 0.1 °C and 0.2 °C, 1.0 
mm for thermometers graduated to 0.5 °C.  
7.1.4 The thickness of t he lines shall not be more than one -fifth of the scale spacing.  
7.1.5 The maximum permissible errors, positive or negative, shall be 0.10 °C if the thermometer is 
graduated to 0.1 °C, 0.20 °C if the thermometer is graduated to 0.2 °C or 0.5 °C.  
7.1.6 Durin g the initial verification, the error of the incorporated thermometer shall be determined at a 
minimum of three points in the scale range.  
7.2 Thermometers not incorporated in the instrument used to determine the alcoholic 
strength  
7.2.1 If the instrument used for determining the alcoholic strength belongs to class I, the 
thermometer used with this instrument shall be either  
a. of the metallic resistance type, by which the temperature of the water/alcohol mixture can be 
determined respecting the maximum permis sible errors, positive or negative, of 0.10 °C, or  
b. of liquid -in-glass, mercury filled type, graduated to 0.1 °C or 0.05 °C. The mercury filled thermometers 
shall have a scale mark at 0  °C, the minimum scale spacing shall be 0.8 mm and the thickness of the 
lines shall not be more than one -fifth of the scale spacing. The maximum permissible errors, positive 
or negative, shall be one scale interval . 
7.2.2 If the instrument used for determining the alcoholic strength belongs to class II or III, the thermometer 
used with this instrument shall be of the liquid -in-glass, mercury filled type.  
7.2.2.1  The thermometer shall be graduated to 0.1 °C, 0.2 °C or 0.5 °C. It shall have a scale mark at 0 
°C. FDUS 1042 : 2013 
© UNBS 2013 – All rights reserved  5 
 7.2.2.2  The minimum scale spacing shall be 0.8 mm for thermometers g raduated to 0.1 °C or 0.2 °C, 1.0 
mm for thermometers graduated to 0.5 °C.  
7.2.2.3  The thickness of the lines shall not be more than one -fifth of the scale spacing.  
7.2.2.4  The maximum permissible errors, positive or negative, shall be 0.10 °C if the therm ometer is 
graduated to 0.1 °C  or 0.20 °C if the thermometer is graduated to 0.2 °C or 0.5 °C . 
8 Conditions of use  
8.1 When the alcoholometer or alcohol hydrometer is read, the emergent part of the stem shall be dry, 
except in the immediate vicinity of the meniscus. The submerged part of the stem shall be absolutely clean, to 
ensure correct wetting. This condition is met if, when the immersion of the instrument is modified slightly with 
respect to its equilibrium position, the instrument oscillates verticall y without any change in the shape of the 
meniscus.  
8.2 The instruments and sample containers shall be carefully cleaned before use.  
8.3 Water/alcohol mixtures of low alcohol content (up to at least 25 % vol), have a surface tension which 
varies according t o the cleanliness of the surface. Slight traces of impurity are sufficient to produce large 
variations in surface tension. Preferably, a sample container with an overflow should be used for these 
solutions, so that the surface of the liquid can be cleaned immediately before taking a reading with the 
instrument . 
 
 
 
 
 
 
 FDUS 1042 : 2013  
6 © UNBS 2013 – All rights reserved  
 Bibliography  
 OIML R 44 Alcoholometers and alcohol hydrometers and thermometers for use in alcoholometry -
Edition 1985 (E)  
 FDUS 1042 : 2013 
© UNBS 2013 – All rights reserved  7 
 Certification marking  
Products that conform to Uganda standards may be marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licen sed under the certification mark scheme operated by 
the Uganda National Bureau of Standards and in conjunction with the relevant Uganda Standard. The 
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control and testing in accordance with the 
certification mark scheme of the Uganda National Bureau of Standards. UNBS marked products are 
continually checked by UNBS for conformity to that st andard.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 FDUS 1042 : 2013   
 
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