UGANDA STANDARD  
  DUS 970-2 :2022  
Second  Edition  
 
 
 
 Reference number  
DUS 970-2:2022 
© UNBS 2022   
  
Agglomerated stone - Slabs and cut -to-size products for vanity 
and kitchen tops  
 DUS 970-2:2022   
ii © UNBS 2022  – 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 contrac t. Users are 
responsible for its correct application  
© UNBS yyyy  
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form or by any means, electronic or mechanical, including photocopying and m icrofilm, without prior written 
permission from UNBS.  
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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 970-2:2022  
© UNBS 2022  – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ............................  iv 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative referen ces ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4 Requirements  ................................ ................................ ................................ ................................ .........  3 
4.1 Geometric characteristics  ................................ ................................ ................................ ....................  3 
4.1.1  Dimensions  ................................ ................................ ................................ ................................ ............  3 
4.1.2  Tolerances for dimensions for slabs and cut -to-size products  ................................ .......................  3 
4.2 Requirements for surface finish  ................................ ................................ ................................ ..........  4 
4.2.1  General  ................................ ................................ ................................ ................................ ...................  4 
4.2.2  Requirements for surfaces after surface finishing  ................................ ................................ ............  4 
4.2.3  Requirements for the backside  ................................ ................................ ................................ ............  4 
4.2.4  Requirements for the edges  ................................ ................................ ................................ .................  5 
5 Characteristics of agglomerated stones for vanity and kitchen tops  ................................ ..............  5 
5.1 General  ................................ ................................ ................................ ................................ ...................  5 
5.2 Visual appearance  ................................ ................................ ................................ ................................ . 5 
5.4 Apparent density and water absorption ................................ ................................ ..............................  5 
5.5 Flexural tensile strength  ................................ ................................ ................................ .......................  5 
5.6 Thermal shock resistance  ................................ ................................ ................................ ....................  5 
5.7 Impact resistance  ................................ ................................ ................................ ................................ .. 5 
5.8 Chemical resistance  ................................ ................................ ................................ ..............................  5 
5.9 Linear thermal expansion coefficient  ................................ ................................ ................................ .. 6 
6 Contact with food  ................................ ................................ ................................ ................................ .. 6 
7 Marking, labelling and packagin g ................................ ................................ ................................ ........  6 
8 Verification of constancy of performance during the production  ................................ ....................  6 
8.1 General rules  ................................ ................................ ................................ ................................ ..........  6 
8.2 Type testing of the agglomerated stone material properties ................................ ............................  6 
8.3 FPC – Tests to be carried out  ................................ ................................ ................................ ...............  7 
Annex  A (normative)  Reference sample, visual inspection and acceptance criteria  ................................ . 8 
Bibliography  ................................ ................................ ................................ ................................ ......................  10 
 DUS 970-2:2022   
iv © UNBS 2022  – All rights reserved  
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry o f 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 deliberate 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 ###, [name of committee] , 
Subcommittee SC ##, [name of subcommittee] . 
This second/third/… edition cancels and replaces the first/second/… edition ( US nnn-n:yyyy), which has been 
technically revised.  
US nnn  consists of the following parts, under the general title Introductory element — Main element :  
  Part n: Part title  
  Part [n+1]: Part title  
  Part [n+2]: Part title  
 DUS 970-2:2022  
© UNBS 2022  – All rights reserved  v 
  
 UGANDA STANDARD  DUS 970-2 :2022 
 
© UNBS yyyy – All rights reserved  1 
 Agglomerated stone - Slabs and cut -to-size products for vanity 
and kitchen tops  
1 Scope   
This document specifies requirements and appropriate test methods for slabs and cut -to-size products of 
agglomerated stone which are made for use as vanity and kitchen tops, or other similar use in furnishing (e.g. 
splash zone).  
NOTE  “Agglomerated stones” are commercially termed “engineered -stones”.  
This document does not cover secondary operations including site installation .  
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 10545 -3, Ceramic tiles — Part 3: Determination of water absorption, apparent porosity, apparent 
relative density and bulk density  
US ISO 10545 -4, Ceramic tiles — Part 4: Determination of modulus of rupture and breaking strength  
US ISO 10545 -9, Ceramic tiles — Part 9: Determination of resistance to thermal shock  
US ISO 10545 -5, Ceramic tiles — Part 5: Determination of impact resistance by measurement of coefficient of 
restitution  
US ISO 10545 -13, Ceramic tiles — Part 13: Determination of chemical resistance  
US ISO 10545 -8:2014, Ceramic tiles — Part 8: Determination of linear thermal expansion  
US ISO 10545 -2, Ceramic tiles — Part 2: Determination of dimensions and surface quality  
US 970 -1, Agglomerated sto ne-slabs and cut -to-size product - Part 1: Terminology of their components  
ISO 11664 -2, Colorimetry - Part 2: CIE standard illuminants  
3 Terms and definitions   
For the purposes of this document, the following terms and definitions apply.  
ISO and IEC main tain terminological databases for use in standardization at the following addresses:  
— ISO Online browsing platform: available at http://www.iso.org/obp   
2 © UNBS 2022  – All rights reserved  
 3.1 
rough slab  
semi -finished agglomerated stone product with edges obtained either by sawing from a bl ock or by moulding, 
the size of which is given by nominal dimensions (length - width - thickness, in this order), expressed in 
millimetres and the surface of which may or may not be the finished surface  
Note 1 to entry: Examples are given in Figure 1.   
 
Key 
R1 surface roughness  
 
Figure 1 — Examples of rough slabs  
3.2  
slab 
finished agglomerated product obtained from rough slabs, the dimensions of which are given by length - width 
- thickness (in this order), expressed in millimetres according to defined to lerances and the surface of which is 
a finished surface ready to use solid unit of clay formed into any of a range of generally rectangular planar 
shapes while plastic and fired in kiln  and are used for roofing  
3.3  
cut-to-size product  
finished agglomerat ed product obtained from a rough slab or a slab, the dimensions of which 
need to be referred to in a template or a drawing  
Note 1 to entry:  Examples are given in Figure 2  DUS 970-2:2022  
© UNBS 2022  – All rights  reserved  3 
 
 
Figure 2 — Examples of cut -to-size products  
4 Requirements  
4.1 Geometric characteri stics  
4.1.1  Dimensions  
The dimensions (length l, width b and thickness d, in this order, expressed in millimetres) of a slab and a cut -
to-size product may be declared by the manufacturer.  
The dimensions of cut -to-size products shall be referred to a templa te or a drawing.  
4.1.2  Tolerances for dimensions for slabs and cut -to-size products  
Tolerances in dimensions of slabs and cut -to-size products shall be as given in Table 1. The dimensions (i.e. 
length, width and thickness) of slabs and cut -to-size product s shall be  determined . 
Stricter deviations may be declared by the manufacturer  
Table 1 — Tolerances in dimensions for slabs and cut -to-size products  
Characteristics  Tolerances on dimensions of  
slabs  cut-to-size products  
Length (l) and width (b)  > 1 000 mm  
- 20 mm/+10 mm  ±1.0 mm  
Other dimensions with 
reference to the template  - ±1.0 mm   
4 © UNBS 2022  – All rights reserved  
 Thickness (d)  ±1.2 mm  
Squareness  ±0.2 % a  
Flatness:  
 Centre curvature  
 edge curvature  
 warping  ±0.2 %  
a Percentage is calculated on the diagonal s. 
 
4.2 Requirements for surface finish  
4.2.1  General  
Surface finishes shall extend uniformly to the edges of slabs and cut -to-size products. The uniformity shall be 
guaranteed on at least 90 % of the total surface of the element.  
Surfaces of slabs and c ut-to-size products shall have a regular appearance as a result of the finishing process 
and may be worked to meet the finish declared.  
Stricter values may be declared by the manufacturer.  
4.2.2  Requirements for surfaces after surface finishing  
Surfaces sh all have a regular appearance as a function of the finishing process and shall be worked to meet 
the finish declared (e.g. by submission of samples beforehand between the purchaser and supplier).  
The surface roughness of the visible face can be directly ob tained by moulding and to present an aspect 
structured with relief.  
EXAMPLE  Examples of the surface finishes are:  
— sandblasted surfaces (obtained for example by means of a sandblasting action),  
— fine ground surfaces (obtained for example by means of a g rinding disk of grain size F 200),  
— honed finished surfaces (obtained for example by means of a polishing disk with grain size F 400),  
— highly polished surfaces (obtained for example by means of a polishing disk or felt),  
— structured aspect (obtained by  catch of print or artistic creation).  
If other types of surface finishes are used, these shall be declared by the manufacturer  
For finely ground surfaces, honed surfaces and highly polished surfaces, it falls under the responsibility of the 
manufacturer to declare, according to the colour of the product, the minimum degree of gloss to be expected.  
4.2.3  Requirements for the backside  
The unexposed surface shall have a regular appearance. Small cracks or cuts are permitted within 10 cm 
from the sides of the  slabs.  
When the finishing process for the unexposed surface foresees a calibrated surface, the maximum surface 
roughness shall not exceed 0.5 mm.  DUS 970-2:2022  
© UNBS 2022  – All rights  reserved  5 
 4.2.4  Requirements for the edges  
The edges of the cut -to-size product shall be referred to a drawing and tole rances shall be defined 
accordingly.  
5 Characteristics of agglomerated stones for vanity and kitchen tops  
5.1 General  
The following characteristics shall be declared when subject to regulatory requirements and may be declared 
otherwise with reference to th e conditions of the end usage.  
Contractual specifications may be used to establish reference values, e.g. stated in design or supplier data 
sheet, due account taken of any regulatory requirements applicable.  
5.2 Visual appearance  
When required, the colour,  roughness, of the slabs and cut -to size products shall be identified visually, e.g. by 
a range of samples selected in agreement by manufacturer and purchaser following the criteria given in US 
ISO 10545 -2. 
Any visual variations, e.g. inclusions an d veins, are permissible provided that they are characteristic of the 
relevant type of agglomerated stone and provided that they do not adversely affect any performance of the 
other characteristics of the slabs and cut -to-size products.  
Reference sample, v isual inspection and acceptance criteria are described in Annex A.  
5.4 Apparent density and water absorptio n 
the values for apparent density and water absorption shall be determined according to US ISO 10545 -3 or 
equivalent  and the result of the water absorption shall be declared accordingly.  
5.5 Flexural tensile strength  
The flexural strength shall be determined according to US ISO 10545 -4 or equivalent and the result expressed 
accordingly.  
5.6 Thermal shock resistance  
Where subject to regulatory requirements or where slabs or cut -to-size products is expected to be subject to 
critical ther mal cycles, thermal shock resistance shall be determined according to US ISO 10545 -9 and the 
result expressed and declared as thermal shock resistance value.  
5.7 Impact resistance  
Where subject to regulatory requirements or where slabs or cut -to-size products are expected to be subject to 
impact of hard falling objects, impact resistance shall be determined according to US ISO 10545 -5 and the 
result expressed and declared as value.  
5.8 Chemical resistance  
Where subject to contractual request or where the slabs and cut-to-size products are expected to be subject  
to aggressive  chemical actions, chemical  resistance shall be determined  according  to US ISO 10545 -13 and 
the result expressed accordingly.   
6 © UNBS 2022  – All rights reserved  
 5.9 Linear thermal expansion coefficient  
Where subject t o contractual request or where slabs or cut -to-size products is expected to be subject to 
relevant dimensional variations due to temperature changes, linear thermal expansion shall be determined 
according to US ISO 10545 -8 and the result expressed and declare d as linear thermal expansion coefficient.  
6 Contact with food  
When intended for use as kitchen tops, the slabs and cut -to-size products are in occasional contact with food. 
Polished and washable products are not subject to any bacterial growth if properl y maintained.  
Products having incorporated anti -bacterial agents should be tested, when requested, in specialized 
laboratories.  
7 Marking, labelling and packaging  
As a minimum of identification, each consignment of slab or cut -to-size products shall specif y on a label 
and/or packaging and/or accompanying documents the following information:  
— classification of the agglomerated stone according to US 970 -1 (i.e. type of binder/mineral nature of the 
aggregate);  
— maximum grain size: coarse (≥15 mm), medium (≥4 mm and < 15 mm) or small (<4 mm);  
— finish surface: e.g. polished surface, sand blasted, etc ; 
— dimensions: length, width and thickness.  
The number of labels shall be sufficient to identify the delivered p roducts according to the type of packaging.  
The slabs and cut -to-size products shall be clean before packaging and transporting. Sensitive polished 
surfaces shall be protected by appropriate means.  
Slabs and cut -to-size products which are susceptible to st ains shall get special attention in order to protect 
them.  
Packing and tapes which are likely to stain shall not be used. Products with caustic properties may not be 
used.  
8 Verification of constancy of performance during the production  
8.1 General rules  
The compliance with the requirements of this standard and with the stated values shall be demonstrated by 
type testing and additionally the manufacturer shall exercise a permanent factory production control (FPC) 
and register the results.  
8.2 Type testing o f the agglomerated stone material properties  
Type testing of an agglomerated stone product shall be carried out (see Table 2):  
— to demonstrate compliance with this document test method or at the beginning of production of a new 
agglomerated stone product,  DUS 970-2:2022  
© UNBS 2022  – All rights  reserved  7 
 — when significant variations occur in the production process, determined visually or by significant changes 
in FPC results.  
Tests previously performed in accordance with the provisions of this document (same material/product, same 
characteristic measured  with same test method, same sampling procedure) may be taken into account. The 
evaluation of the values may be supported by a “test report”, provided that the tests have been performed 
according to the requirements and test methods of this document.  
The r esults of the selected tests shall be expressed as referred to in Clauses 4 and 5.  
Table 2 — List of characteristics for type testing  
Reference subclause 
for applicability  Characteristics  Test method  
4.1 Geometric characteristics   
5.2 Visual appearance  Annex A  
5.4 Apparent density and water absorption   US ISO 10545 -3  
5.5 Flexural tensil e strength  US ISO 10545 -4  
5.6 Thermal shock resistance  US ISO 10545 -9 
5.7 Impact resistance  US ISO 10545 -5  
5.8 Chemical resistance  US ISO 10545 -13 
5.9 Linear thermal expansion coefficient  US ISO 10545 -8  
8.3 FPC – Tests to be carried out  
8.3.1  Sampling for FPC shall be carried out by a proper and careful procedure. An adequate number of 
samples has to be taken to obtain a good estimatio n of the batch. A representative sample of adequate size 
and characteristic of the agglomerated stone slabs shall be taken from the batch to be tested, taking into 
account the intended use of the product.  
8.3.2  The tests to be carried out are part of the F PC. The manufacturer shall exercise a permanent internal 
production control.  
The results of the tests carried out during FPC shall demonstrate the compliance to the requirements  
The manufacturer shall establish the FPC and shall state the frequency of test ing, except for reaction to fire.  
Manufacturers' records may include at least the following information: identification of the product tested, 
information on sampling (place of sampling, identification of the production lot sampled, frequencies of 
sampling , size and number of samples), test methods applied, results of the test carried out, calibration 
records of apparatus.  
  
8 © UNBS 2022  – All rights reserved  
 Annex  A 
(normative)  
 
Reference sample, visual inspection and acceptance criteria   
A reference sample shall be an adequate number of pie ces of agglomerated stone of sufficient size to indicate 
the general appearance of the finished work. The dimensions of individual pieces shall be at least 0.01 m2 
(typical values are between 0.01 m2 and 0.25 m2 in face area but may be more) and shall indi cate the range of 
appearance regarding the colouring, the vein pattern, the physical structure and the surface finish.  
Evaluation of the reference sample does not imply strict uniformity between the sample itself and the actual 
supply; natural variations i n tonality may always occur due to natural raw materials.  
All the differences in aesthetical pattern between the slabs or cut -to-size products and the reference sample 
shall be considered typical of the agglomerated stone and not as flaws. Therefore, they shall not become a 
reason for rejection, unless their presence exceeds 15 % of the surface and the typical pattern of the 
agglomerated stone is lost.  
Any comparison between a production slab or cut -to-size product and the reference sample shall be carried 
out by placing the reference sample in a vertical position against the production slab or cut -to- size product 
and viewing them at a distance of about two metres under normal daylight conditions and recording any 
visible differences in the characteristics of the agglomerated stone (see Figure A.1). According to this method, 
the shading tolerance and the gloss value (in the case of fine ground, honed or highly polished surfaces) 
measured at six different points of the slab or tile shall be evaluated.  
The nam e and address of the manufacturer or supplier of the agglomerated stone shall also be indicated on 
the reference test sample.  
The pieces of agglomerated stone should be analysed under similar conditions, e.g. daylight or artificial light 
D65 (6500K) accord ing to ISO 11664 -2 DUS 970-2:2022  
© UNBS 2022  – All rights  reserved  9 
 
 
Key 
1. reference  sample  
2. production  sample  
3. daylight  
 
Figure A.1 — Comparison between production sample and the reference sample of a slab or a cut -to-
size product   
10 © UNBS 2022  – All rights reserved  
 Bibliography  
BS EN 15388:2020 , Agglomerated stone — Slabs and cut -to- size p roducts for vanity and kitchen tops   
 
 WDUS 970-2:2022  
© UNBS yyyy – All rights reserved  11 
 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 g overned 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. Th e 
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 standard.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 WDUS 970-2:2022    
 
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Price based on nn pages  
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