DRAFT UGANDA STANDARD  
  DUS 2393  
First Ed ition  
2021 -mm-dd 
 
 
 Reference number  
DUS 2393: 2021  
© UNBS 2021   
  
Ceramic /pottery  handicrafts  — Specification  
 DUS 2393: 2021  
ii © UNBS 2021  – 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 provisions of a contract. Users are 
responsible for its corr ect application  
© UNBS 2021   
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 photocopying and microfilm, without prior written 
permi ssion 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 4 333 2 50/1/2/3  
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  DUS 2393:2021  
© UNBS 2021  – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ .............................  v 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Requirements  ................................ ................................ ................................ ................................ .........  2 
4.1 General requirements  ................................ ................................ ................................ ...........................  2 
4.1.1  Categories  ................................ ................................ ................................ ................................ ..............  2 
4.1.7  Manufacturing  ................................ ................................ ................................ ................................ ........  3 
4.1.8  Workmanship  ................................ ................................ ................................ ................................ .........  3 
4.1.10  Finish  ................................ ................................ ................................ ................................ ......................  3 
4.1.11  Decoration  ................................ ................................ ................................ ................................ ..............  3 
4.2 Specific requirements  ................................ ................................ ................................ ...........................  3 
4.2.1  Limits of contaminants  ................................ ................................ ................................ .........................  3 
4.2.2  Warpage  ................................ ................................ ................................ ................................ .................  4 
4.2.4  Porosity  ................................ ................................ ................................ ................................ ..................  4 
4.2.6  Ceramic decoration colour  ................................ ................................ ................................ ...................  4 
5 Sampling  ................................ ................................ ................................ ................................ ................  5 
6 Dimensions  ................................ ................................ ................................ ................................ ............  5 
7 Packaging  ................................ ................................ ................................ ................................ ...............  5 
8 Labelling/ Marking  ................................ ................................ ................................ ................................ . 5 
Annex  A (normative)  Test Method for warpage  ................................ ................................ .............................  6 
A.1 Out-of-roundness  ................................ ................................ ................................ ................................ .. 6 
A.2 Edge warpage and slope for fla tware  ................................ ................................ ................................ .. 6 
Annex  B (Normative)  Method of test for porosity  ................................ ................................ ..........................  7 
B.1 Principle  ................................ ................................ ................................ ................................ .................  7 
B.2 Test pieces  ................................ ................................ ................................ ................................ .............  7 
B.3 Procedure  ................................ ................................ ................................ ................................ ...............  7 
B.4 Calculation  ................................ ................................ ................................ ................................ .............  7 
Annex  C (Norm ative)  Test for resistance to thermal shock  ................................ ................................ ..........  9 
C.1 Principle  ................................ ................................ ................................ ................................ .................  9 
C.2 Apparatus  ................................ ................................ ................................ ................................ ...............  9 
C.2.1  Air-Oven  ................................ ................................ ................................ ................................ .................  9 
C.3 Reagent  ................................ ................................ ................................ ................................ ..................  9 
C.3.1  Eosin Solution  ................................ ................................ ................................ ................................ ....... 9 
C.4 Procedure  ................................ ................................ ................................ ................................ ...............  9 
Annex  D (Normative)  Test for Chipping resistance  ................................ ................................ .....................  10 
D.1 Principle  ................................ ................................ ................................ ................................ ...............  10 
D.2 Apparatus  ................................ ................................ ................................ ................................ .............  10 
D.2.1  Impact Tester  ................................ ................................ ................................ ................................ ....... 10 
D.3 Procedure  ................................ ................................ ................................ ................................ .............  10 
Anne x E (Normative)  Impact strength ,Nm Minimum  ................................ ................................ ..................  11 
E.1 Principle  ................................ ................................ ................................ ................................ ...............  11 
E.2 Apparatus  ................................ ................................ ................................ ................................ .............  11 
E.2.1  Impact Tester  ................................ ................................ ................................ ................................ ....... 11 
E.3 Procedure  ................................ ................................ ................................ ................................ .............  11 DUS 2393: 2021  
iv © UNBS 2021  – All rights reserved  
 Annex  F (Normative)  Test for crazing resistance  ................................ ................................ ........................  12 
F.1 Procedure  ................................ ................................ ................................ ................................ ............  12 
Annex  G (Normative)  Test for resistance to detergents  ................................ ................................ .............  13 
G.1 Principle  ................................ ................................ ................................ ................................ ...............  13 
G.2 Reagent  ................................ ................................ ................................ ................................ ................  13 
G.2.1  Detergent  ................................ ................................ ................................ ................................ .............  13 
G.3 Procedure  ................................ ................................ ................................ ................................ ............  13 
Annex  H (Normative)  Test method for ceramic/ pottery handcraft decoration  ................................ ........  14 
H.1 Boiling water proof test  ................................ ................................ ................................ ......................  14 
H.1.1  Principle  ................................ ................................ ................................ ................................ ...............  14 
H.1.2  Procedure  ................................ ................................ ................................ ................................ ............  14 
H.2 Alkali proof test  ................................ ................................ ................................ ................................ ... 14 
H.2.1  Principle  ................................ ................................ ................................ ................................ ...............  14 
H.2.2  Procedure  ................................ ................................ ................................ ................................ ............  14 
H.3 Acid proof test  ................................ ................................ ................................ ................................ ..... 14 
H.3.1 Principle  ................................ ................................ ................................ ................................ ...............  14 
H.3.2  Procedure  ................................ ................................ ................................ ................................ ............  14 
Annex  C (Informative)  Categories of ceramic /pottery handicrafts  ................................ ...........................  15 
A.1 Table wares  ................................ ................................ ................................ ................................ .........  15 
A.2 Domestic containers  ................................ ................................ ................................ ..........................  15 
A.3 Cooking / firing ceramics  ................................ ................................ ................................ ...................  15 
A.4 Ceramics forms for sound  ................................ ................................ ................................ .................  15 
A.5 Toys and games  ................................ ................................ ................................ ................................ .. 15 
A.6 Ceramic furniture  ................................ ................................ ................................ ................................  15 
A.7 Ceramic jewellery ................................ ................................ ................................ ................................  15 
A.8 Sanitary ceramics  ................................ ................................ ................................ ...............................  15 
A.9 Ceramic food preparing u tensils  ................................ ................................ ................................ ....... 16 
A.10  Garden ceramics  ................................ ................................ ................................ ................................ . 16 
A.11  Ceramics sculpture  ................................ ................................ ................................ ............................  16 
A.12  Gallery ceramics/ interior decoration  ................................ ................................ ...............................  16 
Bibliography  ................................ ................................ ................................ ................................ .....................  17 
 
 DUS 2393:2021  
© UNBS 2021  – All rights reserved  v 
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Trade , Industry and 
Cooperatives established under Cap 327 , of the Laws of Uganda , as amended .  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  Agreement  of the World Trade Organisation (WTO).  
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to d eliberate on standards in a given field or area and consists of key stakeholders 
including government, academia, consumer groups, private sector and other interested parties.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
The committee responsible for this document is Technical Committee UNBS/TC 311, [Crafts and related  
products ], 
  
 DRAFT UGANDA STANDARD  DUS 2393: 2021  
 
© UNBS 2021 – All rights reserved  1 
 Ceramic /pottery handicrafts  — Specification  
1 Scope   
This Draft Uganda Standard specifies requirements, sampling and test methods for ceramic/ pottery 
handcrafts  such as; table ware , domest ic containers, cooking/ firing ceramics, toys and games , ceramic 
furniture , lighting ceramics , garden ceramics , ceramics sculpture  and gallery ceramics/ interior decoration  
This Draft  Uganda  Standard is not applicable to other ceramic products which  have standards specific to them 
including but not limited to jewellery , bricks, tiles , cooking stoves  
2 Normative references   
The following referenced documents referred to in the text in such a way that some or all of their content 
constitutes requirements of this document. For dated references, only the edition cited applies. For undated 
references, the latest edition of the referenced document (including any amendments) applies.  
US ISO 8391 -1:1986 , Ceramic cookware in contact with food ─ Release of lead and cadmium ─ Part 1: 
Methods of test  
3 Terms and definitions   
For the purposes of this document, the following terms and definitions apply.  
ISO and IEC maintain terminological databases for use in standardization at the following addres ses:  
— ISO Online browsing platform: available at http://www.iso.org/obp  
3.1  
ceramic product  
Inorganic non -metallic item made from clay and hardened by heat  
3.2 
handcraft  
made skilfully using hands from raw materials  
Note 1  Finishing may be done using t ools or machines  
3.3 
raw material  
basic materials such as clay or any other materials used to make a  ceramic/ pottery handcraft  
3.4 
lot  
all items of same shape, size, decoration and mat erials of manufacture belong ing to the same batch of 
manufacture   
2 © UNBS 2021  – All rights reserved  
 3.5 
warpage  
deviation from shape or roundness  
3.6  
food ware  
ceramic ware used in the preparation, cooking, serving or storage of food and beverages  
3.7 
porosity  
ratio of the volume of open pores and voids to the total volume occupied by the solid  
3.8 
glaze  
having a shiny surface or coating  
3.9 
crazing  
hair like cracking which occurs in fired glazes or other ceramic coatings due to critical tensile stresses  
3.10 
pottery  handicrafts  
products  made from  clay and other ceramic materials, which are fired at high te mperatures to give them a 
hard, durable form  
3.11 
table ware  
ceramic products used for serving and eating food  such as: dishes, glasses, knives, forks, cups, plates, tea 
pots, drinking water pots  etc. 
4 Requirements   
4.1 General requirements  
4.1.1  Categor ies  
Any ceramic / pottery  handicraft  shall fall into one of the two categories in Table 1.  
Table 1 — Categories of ceramic / pottery  handicraft s 
Category  Intended application  
Category 1  Ceramic / pottery  
handicraft  A ceramic / pottery  handcraft  whose use lea d 
them to contact with foodstuff  
Category 2  ceramic / pottery  
handicraft  A ceramic / pottery  handicraft  whose use is 
not intended for foodstuffs  
 
NOTE 1  An example of  category 1: table  ware.  
NOTE 2  An example of category2 : flower vases  
4.1.2  The handle wh en provided shall always be symmetrical and must be able to support the weight of the 
ceramic / pottery  handicraft  and its content s.  
4.1.3  Ceramic / pottery  handicraft s shall not contain any harmful product s to the environment whether during 
service or disp osal.  DUS 2393: 2021  
© UNBS 2021  – All rights reserved  3 
 4.1.4  Ceramic / pottery  handicraft s shall not shatter upon grabbing  
4.1.5  Raw materials shall be essentially ceramic materials. Additional materials can be used to improve 
properties of the intended product.  
4.1.6  Raw materials, for category 1 , shal l not result, directly or indirectly, in becoming a component of food, 
or otherwise affecting the characteristics of food, including the imparting of a colour, taste, or odour to the 
food;  
4.1.7  Manufacturing  
4.1.7 .1 Manufacturer shall use his/her hands to shape the product. Finishing may be done by hands or 
equipment.   
4.1.7 .2 A ceramic /pottery  handicraft shall be free from deleterious substances, flaws and other 
manufacturing defects which might affect their intended utility.  
4.1.7 .3 A ceramic  handicr aft/ pottery  product shall be sound and true to shape and heat maybe used to 
optimize the properties of the product.  
4.1.8 Workmanship  
4.1.8.1 Ceramic/ pottery handicrafts  in one batch shall be of the same shape.  
4.1.8.2 Where items have lids, the lids  shall  fit firmly .  
4.1.9 The side which comes in to contact with foodstuffs shall have a smooth surface finish and shall be free 
from any defects which would affect its intended use.  
4.1.10 Finish  
4.1.10.1 The surface of the ceramic/ pottery handicraft  shall be as free as possible from any visual defects.  
4.1.10.2 Paint and other organic coatings can be used on surfaces of ceramic / pottery  handcrafts . 
However, only food grade paints and coatings shal l be used for category 1  
4.1.1 1 Decoration  
Decoration s hall be done in accordance with agreement between the manufacturer and the customer.  
4.2 Specific requirements  
4.2.1  Limits of contaminants  
When tested in accordance with test method specified in Table 2, category 1  ceramic/ pottery handicrafts  shall 
meet the limits as specified below  
Table 2 — Maximum permissible leve ls of contaminants in category 1  ceramic / pottery  handicrafts  
Contaminants  Maximum permissible levels 
ppm  Test method  
Lead  5 US ISO 8391 -1 
Cadmium  0.5 
  
4 © UNBS 2021  – All rights reserved  
 4.2.2 Warpage  
Warpage shall be d etermined in accordance with Annex A and shall meet the permissible limits specified in 
Table 3.  
Table 3 — Permissible limits for warpage  
Parameter  Out-of-roundness limit, 
% Edge warpage (mm)  Slope 
(degree, ˚) 
Permissible limit 
value  0.8 1.5 1.5 
4.2.4  Porosity   
4.2.4 .1 Porosity of a  ceramic / pottery  handicraft  is indicated by the amount of water absorbed.  
4.2.4 .2 When t ested in accordance with Annex B , water absorption shall not exceed 3 % for glazed 
products and 6 % for unglazed products.  
4.2.5 The ceramic/ pottery ware shall conform to the r equirements indicated in table 4 . 
Table 4-Requirements for Ceramic ware  
Parameter  Requirements  Test method  
Thermal shock , °C Minimum  160 Annex C  
Chipping resistance, Nm , Minimum  0.14 Annex D  
Impact strength , Nm, Minimum  0.267  Annex E  
Crazing  None of the test pieces show crazing  Annex F 
4.2.6  Ceramic decoration colour  
4.2.6.1  The decoration  colour  of the ceramic/ pottery handicraft shall be highly resistant to acid with a 
maximum tolerance up to Grade No. 1  (see Table 5 ) when tested in accordance with the method given in 
Annex H.  
4.2.6.2  The decoration colour on the surface of the ceramic/ pottery handicraft  shall be highly resistant to 
alkali to Grade No. 2 (see Table 5 ) when tested in accordance with the method given in Annex H.  
4.2.6 .3.  The decoration colour on the ceramic/ pottery handicraft  surface shall be highly resistant to 
boiling water with a maximum toleranc e up to Grade No. 1 (see Table 5 ) when tested in accordance with the 
method given in Anne x H. 
4.2.6.4  The decoration colour on the ceramic/ pottery handicraft  surface shall be highly resistant to 
household detergent with a maximum toleranc e up to Grade No. 1 (see Table 5 ) when tested in accordance 
the method given in Annex G.  
Table 5 ─ Grades based on chemical test result  
Item Grades  
0 1 2 3 
Surface luster  Unchanged  Slightly matte  Considerably matte  No luster  
Colour  fading  Unchanged  Slightly fading  Considerably fading  Extreme fading  
 DUS 2393: 2021  
© UNBS 2021  – All rights reserved  5 
 5 Sampling  
5.1 When sampling for clause 4.2.1  (limits of contaminants), four items shall be sampled. For other tests, 
three items shall be sampled.  
5.2 Each of the items shall be  identical in size and shape.  
5.3 Tests for workmanship finish and visual assessment shall be done on all samples, those t hat pass shall 
then be subjected to the other tests.  
6 Dimensions  
The dimensions shall be subject to a tolerance of ± 0.5 %. For ceramic/ pottery handcrafts  where volume is 
important, a volume tolerance of ± 2.5 % shall apply.  
NOTE 1 An example of a  ceramic/ pottery  handcraft  where volume is important is a cup  
7 Packaging  
Ceramic / pottery handcrafts  shall b e packaged in suitable packages  that prevent damage during normal 
handl ing, storage and transportation .  
8 Labelling / Marking  
Both bulk package and individual ceramic / pottery  handcraft (s) shall be legibly and i ndelibly labelled / marked  
with the following information:  
a) Manufacturer’s/supplier’s name, trade mark or both;  
b) Batch and lot number  
c) Dimension(s)/ volume of the packaged ceramic / pottery  product (s)  
d) Country of origin/ manufacture  
NOTE 1 Where items of different dimensions or volume are in one bulk package, a range of dimensions or volumes of 
packaged items can be labelled accordingly.  
  
6 © UNBS 2021  – All rights reserved  
 Annex  A 
(normative)  
 
Test Method  for warpage  
A.1 Out-of-roun dness  
A dial indicator shall be used to determine the out -of-roundness of a ceramic/ pottery Handcraft . The sample, 
resting on its foot on a flat surface, shall be blocked in a manner to allow its rotation. The indicator plunger 
shall strike the outer rim edge o f the sample from above at a 45 ˚ angle to a horizontal plane. The sample shall 
be rotated and the low and high readings shall be taken. The difference between the two readings shall 
denote the out of  roundness  
A.2 Edge warpage and slope for flatware  
Edge warpage and slope of items shall be determined as follows:  
a) Invert the sample and place it face down on a surface plate,  
b) Place a weight across the resting surface of the item to stabilize it in place,  
c) Attempt to insert a feeler gauge between the sur face and any portion of the sample edge. The 
readings of the feeler gauge will indicate the warpage on the edge of the item.  
d) Remove the weight from the resting surface and r eplace it with an inclinometer and  
e) Determine the slope of the resting surface.  DUS 2393: 2021  
© UNBS 2021  – All rights reserved  7 
 Annex B 
(Normative ) 
 
Method of test for porosity  
B.1 Hot water bath method  
B.1.1 Principle  
Water absorption of the sample is determined by the amount of water absorbed by boiling the sample in 
distilled water and finding the increase in the mass   
B.1.2 Test pieces  
Five test pieces from five different test samples are cut or broken to get a surface area of about 16 cm2. At 
least two flat faces of the test pieces shall be glazed and other sides unglazed. The test  samples  shall be 
freshly cut or broken.  
B.1.3 Procedure  
B.1.3.1 Dry the test pieces to a constant weig ht at a temperature between 110˚C and 1 50˚C and then 
cool to room tem perature in a desiccator.  
B.1.3.2 Weigh  the pieces to an accuracy of not less than 0.01g and place in a vessel from which the air 
can be removed maintaining the pressure at less than 3cm of mercury for one hour.  
B.1.3.3 Admit cold or freshly boiled  distilled water to the vessel without reducing the vacuum until the 
pieces are covered.  
B.1.3.4 Then, admit air to the vessel without removing the pieces boil the pieces in distilled water for not 
less than 20 min. Cool, wipe the pieces with a damp soft cotton cloth to remove adhering surface water and 
weigh quickly  
B.1.4 Calculation  
Water a bsorption of the test pieces shall be calculated as follows:  
 
Where:  
𝑊1 weight of the dry test piece, and   
𝑊2 weight of the test piece after treatment  
All the six test pieces shall show a water absorption as specified in clause 4.2.6.2   
8 © UNBS 2021  – All rights reserved  
 B.2 Cold -water  bath method  
B.2.1 Procedure  
B.2.1.1  Dry the test pieces to a constant weight at a temperature between 110˚C and 150˚C and then 
cool to room temperature in a desiccator  
B.2.1.2  Weigh t he test pieces to an accuracy of not less than 0.01g  (W1) 
B.2.1.3  Immerse  the sample s in water  at room temperature  for 24 hours, remove, wipe the pieces with a 
damp soft cotton cloth to remove adhering surface water and weigh quickly  (W2) 
B.2.1.4  Water absorpt ion of the sample shall be calculated as  in B.1.4  DUS 2393: 2021  
© UNBS 2021  – All rights reserved  9 
 Annex  C 
(Normative)  
 
Test for resistance to thermal shock  
C.1 Principle  
Thermal shock is measured by the difference  between the upper temperature T 1 to which the specimens are 
heated and the lower temperature T 2 of the cold w ater-bath into which they are placed after heating. This is a 
test for tendency of crazing due to residual stresses after firing and not due to factors of moisture expansion.  
C.2 Apparatus  
C.2.1 Air-Oven  
With a temperature range of 35 to 250°C and provided  with an air stirrer or circulator to ensure uniformity of 
temperature. The oven shall have a thermostat capable of maintaining the temperature constant to ± 1°C up 
to 180°C and ±2°C between 180 and 250°C. It shall also be provided with a thermometer capab le of being 
read to an accuracy of ±1°C.  
C.3 Reagent  
C.3.1 Eosin Solution  
0.5 percent (m/v) in water.  
C.4 Procedure  
C.4.1 Place three specimens in the air -oven previously h eated to the upper temperature T 1 so that the  
difference 
 ) is equal to 120°C, T 2 being the temperature of tap water in the cold water -bath. Maintain  
the samples in the oven at that temperature for 30 min. Then -remove the specimens from the oven, one  at a 
time, by means of tongs with asbestos covered tips, completing the proc ess of transference in 5 ± 1 -5 for each 
article, and immerse the specimens for a specified period of not less than two minutes into the cold  water -bath 
which has b een maintained at temperature T 2. After immersing in the cold water -bath, dry the  specimens a nd 
then immerse in the eosin solution. Examine the test specimens after cleaning. The specimens shall be 
subjected to this test five times.  
C.4.2 The specimens shall be considered to have satisfied the requirement of the test if there is no crazing  
of the glaze or cracking of the ware indicated by coloured hair lines on the surface of any specimen.   
10 © UNBS 2021  – All rights reserved  
 Annex  D 
(Normative)  
 
Test for Chipping resistance  
D.1 Principle  
This test is carried out to ensure that the ceramic/ pottery h andcraft withstands impacts encountered in normal 
day to day use without breaking or chipping.  
D.2 Apparatus  
D.2.1 Impact Tester  
A suitable pendulum type impact tester  
D.3 Procedure  
D.3.1 This test shall be carried out on  flat ceramic/ potte ry handcraft . Place the test specimen between two 
cast iron blocks forming a 90° 'V' and adjust it in such a manner that when the hammer.is hanging vertically 
the center of the impact face of the chipping hammer touches the edge of th e test piece at the pl ane of the 
bisector of the angle of the 'V'. Strike the test piece at three equally spaced points on its periphery with the  
cylindrical end of the hammer with an impact force of 0.14 N.m.  
D.3.2 The ware shall be considered as not conforming  to the test if the impact results in chipping of the 
edge  so that fragments of glaze and body are removed.  
 DUS 2393: 2021  
© UNBS 2021  – All rights reserved  11 
 Annex  E 
(Normative)  
 
Impact strength ,Nm Minimum  
E.1 Principle  
This test is carried out to ensure that the cerami c/ pottery handcraft  withstands impacts encountered in normal 
day to day use without breaking or chipping.  
E.2 Apparatus  
E.2.1 Impact Tester  
A suitable pendulum type impact tester.  
E.3 Procedure  
When testing a plate, saucer or platter, support the ware aga inst three equally spaced 3 mm diameter steel 
halls so that when the hammer is hanging vertically the impact point of hammer touches the centre of the 
bottom of the test piece. When testing a cup or bowl, place the ware on its foot between two cast iron bl ocks 
forming a 90° 'V' whose sides are sufficiently high to support the upper edge of the cup or bowl and adjust it in 
such a manner that when the hammer is hanging vertically, its impact point touches the cup or bowl at its 
upper edge and on the plane of the bisector of the angle of 'V’. Strike the test piece with the spherical end of 
the hammer with an impact force impact of 0.267 N.m.  
A ware such as a plate, saucer or platter shall be considered as not complying  to the test if it develops  a 
rupture which  appears as a hole through the body or as a body crack extending through its rim. A cup or  bowl 
shall be also treated as not conforming if it develops a body crack extending into any portion of the  foot or a 
portion of the body breaks away.  
  
12 © UNBS 2021  – All rights reserved  
 Annex  F 
(Norma tive) 
 
Test for crazing resistance  
F.1 Procedure  
F.1.1 Fresh whole dry articles shall be subjected to the crazing test. They shall be placed loosely at room  
temperature on a suitable support at least 50 mm above water level in an autoclave which shall be of  sufficient 
capacity and equipped with a safety valve, blow -off valve; thermometer, pressure gauge and  heating 
arrangement or other means of sufficient capacity to ensure constant steam pressure within the  autoclave. 
Sufficient amount of distilled water shall be taken in the autoclave. Slight water will remain after  the test. 
Initially the blow -off valve shall be kept open until steam begins to escape thereby expelling most  of the air. 
Also closing the blow -off valve, water shall be kept boiling and the steam pressure increased at  a uniform rate 
until it reaches the pressure  of 5 kg/cm2 within a period of 30 min or one and a half hour  depending on the 
kind of the ware and hold it at the maximum pressure for 1 h. Sufficient heat shall be  applied to maintain a 
constant steam pressure for the specified period.  
F.1.2 The source of heat shall then be shut off and steam pressure released slowly in not less than 30 min  
by opening the blow off valve. The ware shall b e allowed to cool to room temperature in the autoclave. The  
wares then shall be removed and tested for crazing by applying 0.5 percent eosin solution (m/v) in water or  
blue black fountain pen ink to the glazed surface. There should not be any hair like pat tern after application  of 
the dye or ink.  DUS 2393: 2021  
© UNBS 2021  – All rights reserved  13 
 Annex  G 
(Normative)  
 
Test for resistance to detergents  
G.1 Principle  
The ceramic/ pottery handcrafts are immersed into detergent solution at a temperature of 60°C for 48 h and 
loss of gloss of the glaze is compared visually against untested sample.  
G.2 Reagent  
G.2.1  Detergent  
 0.04 percent (m/v)  
G.3 Procedure  
Place fresh, clean whole article or piece in a suitable beaker. Add detergent solution so that the arti cle is 
completely immersed and then cover with watch glass. Place the beaker in an air oven for 48 h at a 
temperature of 60°C. During the period of test, the concentration of the detergent solution shall be maintained 
by adding required amount of water per iodically. At the end of the period, 'remove the test specimen, wash 
with water and dry. Compare the loss of gloss of glaze of the test specimen visually against untested sample.   
14 © UNBS 2021  – All rights reserved  
 Annex  H 
(Normative)  
 
Test m ethod for ceramic/ pottery handcraft  decoration  
H.1 Boiling water proof test   
H.1.1  Principle  
This test determines if fired pigment or luster is affected by boiling water.  
H.1.2  Procedure   
Leave the test piece at 100ºC controlled water bath for 24 hour s. Wash, dry and observe for changes in luster, 
color and peeling -off of pigments or gold.  
H.2 Alkali proof test  
H.2.1  Principle   
This test determines if fired pigment or luster is affected by alkali.  
H.2.2  Procedure  
Dip the test piece into a 0.5% sol ution of sodium carbonate in a controlled water bath at 100ºC for two hours. 
Wash, dry and observe for change in luster, color and peeling -off of pigments gold.  
H.3 Acid proof test  
 H.3.1  Principle   
This test evaluates the quality of design or decoratio n (gold or platinum) on the ware surface and if fired 
pigments of gold on the ware is affected by acid.  
H.3.2  Procedure   
Dip the test piece into a four percent solution of acetic acid. Soak at 25 -55ºC for 24 hours. Wash thoroughly 
with water, dry with cl oth and observe for any change in luster, color and peeling -off of fired pigments or gold.  
  
 DUS 2393: 2021  
© UNBS 2021  – All rights reserved  15 
 Annex  I 
(Informative)  
 
Categor ies of ceramic /pottery handicrafts  
I.1 Table wares  
These include  teapots, coffee  pots, mugs, plates, bowls, jugs, egg cups, platters, ceramic spoons, rice bowls, 
communal eating bowls, ceramic pilgrim flasks, water jars, harvest jugs, ceramic beakers, beer mugs, drinking 
mugs, sourcers , wine jars  
I.2 Domestic containers  
Thes e include : milk pots , water pots (drinking water) eg Ensuuwva , storage water pot e.g. Ettogero , beer 
pots, ceramic bobbles , cosmetic pots , pig banks , Jewellery  pots/ containers , storage jugs , spice pots , Salt 
shakers  
I.3 Cooking / firing ceramics  
Thes e include : ceramic charcoal stoves, incinerators, fire boxes, cooking pots, earthenware Tajine (common 
in Morocco), cooking Casserole (common in Turkey), Oil and Pastille burners, Incense burners, Smoking 
pipes  
I.4 Ceramics forms for sound  
These: clay drums, clay whistl es, clay bells, alert beads  
I.5 Toys and games  
These include  ceramic toys, ceramic dolls, painted cars and buses, articulated figures, ceramic mementos 
(souvenirs), ceramic game marbles, clay masks, moulded plaques  
1.6 Ceramic furniture  
These include  ceram ic tables, ceramic chairs, ceramic door handles, ceramic door knobs  
I.7 Ceramic jewellery  
These include  ceramic beads, ceramic earrings, ceramic buttons, ceramic necklaces, ceramic bungle  
I.8 Sanitary ceramics  
These include  ceramic sinks, ceramic drainage pipes, ceramic soap dishes, washing jugs, washing bowls   
16 © UNBS 2021  – All rights reserved  
 I.9 Ceramic food preparing utensils  
These include  ceramic lemon reamers, ceramic mortar, ceramic pestle, ceramic churning butter containers, 
ceramic bottle yoghurt fermenter  
I.10 Garden ceramics  
These  include  flowerpots, planters, terracotta planters, glazed flowerpots, nursery bed planters  
I.11 Ceramics sculpture  
These include  human figurine, wildlife figurine, religious figurine, traditional religious terms, storytelling 
figurines, abstract figurines , moulded plaques, ceramic mosaics and morals, nativity scenes, funeral figures, 
grave historical figurines  
I.12 Gallery ceramics/ interior decoration  
These include  ceramic art forms, glazed pots, glazed plates, abstract forms, smoked ceramic/pottery forms , 
ceramics murals  DUS 2393: 2021  
© UNBS 2021  – All rights reserved  17 
 Bibliography  
[1] DKS,  432:2019 , Handmade ceramic products — Specification  
[2] DTZS Tableware -Ceramic Ware -Specification  
[3] IS 14179: Methods of test for ceramic tableware  
 
 CDUS  2393: 2021  
© UNBS 2021 – All rights reserved  19 
 Certification marking  
Prod ucts 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 licensed 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 i s 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 standard.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 CDUS 2393: 2021    
 
ICS nn.nnn.nn  
Price based on nn pages  
© UNBS yyyy– All rights reserved