 DRAFT UGANDA STANDARD  
  DUS 202 
Second  Edition  
2020 -mm-dd 
 
 
 Referenc e number  
DUS 202: 2020 
© UNBS 2020   
  
Textiles — Mattress — Specification  
 DUS 202: 2020  
ii © UNBS 2020  – 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 correct app lication  
© UNBS 2020   
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 
permission f rom 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 202:2020  
© UNBS 2020  – All rights reserved  iii 
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ............................  iv 
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  2 
4 Mattress Types  ................................ ................................ ................................ ................................ ...... 3 
4.1 Innerspring mattresses  ................................ ................................ ................................ .........................  3 
4.2 Hybrid mattresses  ................................ ................................ ................................ ................................ . 3 
4.3 Non-innerspring mattresses  ................................ ................................ ................................ ................  3 
5 Requirements  ................................ ................................ ................................ ................................ .........  3 
5.1 Mattress Components  ................................ ................................ ................................ ...........................  3 
5.1.1  Core ................................ ................................ ................................ ................................ .........................  3 
5.1.2  Shell (padding)  ................................ ................................ ................................ ................................ ....... 3 
5.1.3  Ticking material  ................................ ................................ ................................ ................................ ..... 4 
5.2 Dimensions  ................................ ................................ ................................ ................................ ............  5 
5.3 Flammability  ................................ ................................ ................................ ................................ ...........  6 
5.4 Foam  ................................ ................................ ................................ ................................ .......................  6 
6 Specific requirements  ................................ ................................ ................................ ...........................  7 
6.1 Flexible polyurethane mattresses  ................................ ................................ ................................ ....... 7 
6.1.1  Polyether foam  ................................ ................................ ................................ ................................ ....... 7 
6.1.2  Polyester foam  ................................ ................................ ................................ ................................ ....... 7 
6.1.3  Reconstituted foam  ................................ ................................ ................................ ...............................  7 
6.2 Expanded Polyethylene Mattresses  ................................ ................................ ................................ .... 8 
7  Packa ging and labelling  ................................ ................................ ................................ ......................  8 
7.1  Packaging  ................................ ................................ ................................ ................................ ...............  8 
7.2  Labelling  ................................ ................................ ................................ ................................ .................  9 
7.2.1  Ticking m aterial labelling  ................................ ................................ ................................ .....................  9 
7.2.2  Foam labelling  ................................ ................................ ................................ ................................ ....... 9 
8  Sampling  ................................ ................................ ................................ ................................ ................  9 
8.2  Complian ce with the specification  ................................ ................................ ................................ ...... 9 
Annex  A (normative)  Flammability  ................................ ................................ ................................ ................  10 
A.1 Apparatus  ................................ ................................ ................................ ................................ .............  10 
A.2 Test specimens  ................................ ................................ ................................ ................................ ..........  10 
A.3 Procedure  ................................ ................................ ................................ ................................ ...................  10 
Annex  B (normative)  Permanent resistance to solvents  ................................ ................................ .............  11 
B.1 Apparatus  ................................ ................................ ................................ ................................ ...................  11 
B.2 Reagents  ................................ ................................ ................................ ................................ .....................  11 
B.3 Test specimen  ................................ ................................ ................................ ................................ ............  11 
B.4 Procedure  ................................ ................................ ................................ ................................ ...................  11 
B.5 Calculation and reporting  ................................ ................................ ................................ ...................  12 
Bibliography  ................................ ................................ ................................ ................................ ......................  13 
 
 DUS 202: 2020  
iv © UNBS 2020  – All rights reserved  
 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 deliberate on standards in a given field or area and consists of key stakeholders 
including government, academia, consumer groups, private sector and other inter ested 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 7, Textiles, Leath er, Paper 
and Related Products , Subcommittee SC 1, Textiles and Related products . 
This second  edition cancels a nd replaces the following standards:  
US 202 -1:2015, Flexible polyurethane foams — Part 1: Polyether type — Specification  
US 202 -2:2015, Flexible polyurethane foams — Part 2: Mattresses — Specification  
US 202 -3:2015, Flexible polyurethane foams — Part 3: Re constituted foams — Specification  
US 202 -4:2015, Flexible polyurethane foams — Part 4: Polyester type — Specification  DUS 202:2020  
© UNBS 2020  – All rights reserved  v 
  DRAFT UGANDA STANDARD  DUS 202: 2020  
 
© UNBS 2020  – All rights reserved  1 
 Textiles — Mattress — Specification  
1 Scope   
This Draft Uganda Standard specifies the requirements, test methods and sampling of foam mattresses 
suitable for domestic and hotel use.  
This standard does not apply to mattresses used for medical , purposes.   
2 Normative references   
The following referenced documents are 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.  
ISO 2439, Flexible cellular polymeric materials — Dete rmination of hardness (indentation technique)  
ISO 5077 , Textiles — Determination of dimensional change in washing and drying  
US ISO 105 -B02, Textiles — Tests for colour fastness — Part B02: Colour fastness to artificial light: Xenon 
arc fading lamp test  
US ISO 105 -C10, Textiles — Tests for colour fastness — Part C10: Colour fastness to washing with soap or 
soap and soda  
US ISO 105 -D01, Textiles — Tests for colour fastness — Part D01: Colour fastness to drycleaning using 
perchloroethylene solvent  
US ISO 105 -E04, Textiles — Tests for colour fastness — Part E04: Colour fastness to perspiration   
US ISO 105 -X12, Textiles — Tests for colour fastness — Part X12: Colour fastness to rubbing  
US ISO 845, Cellular plastics and rubbers — Determination of apparent density  
US ISO 1798 , Flexible cellular polymeric materials — Determination of tensile strength and elongation at 
break  
US ISO 1856 , Flexible cellular polymeric materials — Determination of compression set  
US ISO 2439, Flexible cellular polymeric materials — Deter mination of hardness (indentation technique)  
US ISO 3071, Textiles — Determination of pH of aqueous extract  
US ISO 3385 , Flexible cellular polymeric materials — Determination of fatigue by constant -load pounding  
US ISO 3801, Textiles — Woven fabrics — Dete rmination of mass per unit length and mass per unit area   
US ISO 7771, Textiles — Determination of dimensional changes of fabrics induced by cold -water immersion    
2 © UNBS 2020  – All rights reserved  
 US ISO 8067 , Flexible cellular polymeric materials — Determination of tear strength  
US ISO 13 934-1, Textiles — Tensile properties of fabrics — Part 1: Determination of maximum force and 
elongation at maximum force using the strip method   
US ISO 13938 -1, Textiles — Bursting properties of fabrics — Part 1: Hydraulic method for determination of 
burst ing strength and bursting distension   
US ISO 13938 -2, Textiles — Bursting properties of fabrics — Part 2: Pneumatic method for determination of 
bursting strength and bursting distension  
3 Terms and definitions   
For the purposes of this document, the follow ing terms and definitions apply.  
3.1  
mattress  
product providing a surface to sleep or rest upon, that is fit for use by human beings for a long period of time, 
consisting of a strong cloth cover filled with materials, and that can be placed on an existin g supporting bed 
structure  
3.2   
ticking  
outermost layer of fabric or related material of a mattress or foundation  
3.3   
filling  
inert substance introduced to a product to achieve desired characteristics  
3.4   
block  
mass of foam formed by a free -rising foam process, in its original form prior to conversion  
3.5   
polyurethane foam  
cellular material produced by the reaction of a polyol with an organic isocyanate in the presence of water and 
that may include catalysts, surface active agents, auxiliary b lowing agents, fillers, plasticizers, colourants and 
any other additives that do not alter the properties of the foam  
3.6   
lot  
not less than 1 m3  and not more than 100 m3  of foam of the same density  and nominal dimensions, from one 
manufacturer, subm itted at any one time for inspection and testing  
3.7  
ultimate elongation (elongation at break)  
percentage strain produced in a specimen stretched to its breaking point  
3.8  
polyether foam  
polyurethane foam formed by the reaction of a polyether polyol w ith a polyisocyanate  
3.9  
reconstituted foam  
composite material that consists of chips of flexible polyurethane foam of the polyether or the polyester type 
(or of a mixture of these types) held together by means of a suitable binder  DUS 202: 2020  
© UNBS 2020  – All rights reserved  3 
 3.10  
polyester foam  
polyurethane foam formed by the reaction of a polyester resin with a polyisocyanate  
4 Mattress Types  
Depending upon the composition of their cores, mattresses are characterised as below:  
4.1 Innerspring mattresses  
Innerspring mattresses shall contain a  series of metal springs joined together in sizes that correspond to the 
dimensions of mattresses (see US 1575)  
4.2 Hybrid mattresses  
Hybrid mattresses shall contain two or more support systems as the core, such as layers of both polyurethane 
foam and innerspr ing units  
4.3 Non-innerspring mattresses  
Non-innerspring mattresses shall not contain any innerspring units. T hese may be  produced from foams such 
as polyurethane, latex, thermobonded polyester, polyethylene or any other resilient filling.  
5 Requirements  
5.1 Mattress Components  
5.1.1  Core  
The core shall consist of any of the following materials:  
a) Springs  
b) Polyurethane  
c) Latex  
d) Polyethylene  
e) Horse hair  
f) Coconut fibre  
5.1.2  Shell (padding)  
All mattresses with a spring interior shall contain a shell. Mattresses with other materials may contain a shell. 
The shell materials used shall include:  
a) Polyether foam  
b) Latex foam  
c) Horse hair and camel hair  
d) Coconut fibres   
4 © UNBS 2020  – All rights reserved  
 e) Polyester (PET or Polye thylene)  
f) Cotton  
g) Wool  
h) Linen  
i) Felt 
j) Jute 
k) Sisal 
These materials shall be either glued and/or s ewed to each other and on the core.  
5.1.3  Ticking material  
5.1.3.1  The ticking or covering material shall be new, clean and free from defects (including splits, tears 
and voids) that detract from the appearance or that may be detrimental to the performance  of the mattress.  
5.1.3.2  The ticking shall show no evidence of holes, tears, loose yarns, spots or odour.  
5.1.3.3  The stitching shall not pucker or have open seams, or loose or untrimmed ends.  
5.1.3 .4 The fibre composition of the thread used for stitching  the fabric on the mattress sh all be 
compatible with the ticking material  
5.1.3 .5 Chemicals which are harmful to the skin or which can react with the rubber foam shall not be 
used in the finishing of the fabric. The pH of the finished fabric shall be as st ated in T able 1.  
5.1.3 .6 The ticking material shall be made from any of the following materials or their blends: cotton, 
polyester, silk, wool, viscose and nylon. The tick ing material  may be fixed to the mattress or removable.  
5.1.3 .7  The fabric width fo r all sizes of mattresses shall be such that when stitched, not more than three 
seams shall be on one side of the width of the mattress. The width of the fabric roll shall be as declared 
subject to a tolerance of ± 2 %.  
Table 1 — Requirements for Ticking m aterial  
Parameter  Requirement  Test 
Methods  
 Polyester  Cellulosic 
(cotton, 
viscose)  Polyester 
cellulosic 
blend  Nylon  
Mass per unit area 
g/m2, min . 63 115 70 63 ISO 3801  
Breaking strength, 
N, min  
 Warp  
 Weft  
 
600 
200  
 
300 
160  
 
600 
200  
 
600 
200 ISO 139 34-1 
Bursting strength, 
kN/m2, min.  202 157 160 202 ISO 13938 -1 
Dimensional 
changes, %, max.  
 Warp  
 Weft  
 
2 
2  
 
4 
4  
 
2 
2  
 
2 
2 ISO 5077  
pH 6.0 — 8.5 US ISO 
3071  
Colour fastness to 
light 5 5 5 5 US ISO 105 -
B02 DUS 202: 2020  
© UNBS 2020  – All rights reserved  5 
 Colour fastness to 
washing, min.  
 Change  
 Staining   
 
4 
4  
 
4 
4  
 
4 
4  
 
4 
4 US ISO 105 -
C10 
Colour fastness to 
rubbing, min.  
 Wet 
 Dry  
 
4 
3  
 
4 
3  
 
4 
3  
 
4 
3 US ISO 105 -
X12 
Colour fastness to 
dry cleaning, min.  
 Change  
 Staining   
 
4 
4  
 
4 
4  
 
4 
4  
 
4 
4 US ISO 105 -
D01 
Colour fastness to 
perspiration, m in. 
 Change  
 Staining   
 
4 
4  
 
4 
4  
 
4 
4  
 
4 
4 US ISO 105 -
E04 
5.2 Dimensions  
When determined in accordance with US ISO 1923, foam mattresses shall conform to the requirements in 
Table 2. For top skin mattresses, the top skin shall have a minimum thickness of  1.5 mm. Mattresses of 
dimensions other than those indicated under Table 2 should be manufactured subject to tender agreement 
between purchaser and supplier. They shall be for purchasers’ use only and shall not be sold in the market.  
Table 2 — Dimensional requirements of mattresses  
Length,* 
mm Width,*  
mm  Thickness,*  
mm  
1 219  610 76 
1 219  610 102 
1 372  610 76 
1 372  610 102 
1 524  762 76 
1 524  762 102 
1 880  762  51  
1 880  762  76  
1 880  762  102  
1 880  915  51  
1 880  915  76  
1 880  915  102  
1 880 915  152  
1880  915 203 
1880  915 254 
1880  915 305 
1 880  1 069  102  
1 880  1 069  152  
1 880  1 069  203 
1 880  1 069  254 
1 880  1 069  305 
1 880  1 219  102  
1 880  1 219  152   
6 © UNBS 2020  – All rights reserved  
 1 880  1 219  203 
1 880  1 219  254 
1 880  1 219  305 
1 880  1 372  152  
1 880  1 372  203 
1 880  1 372  254 
1 880  1 372  305 
1 880  1 524  152  
1 880  1 524  203 
1 880  1 524  254 
1 880  1 524  305 
1 880  1 829  152  
1 880  1 829  203 
1 880  1 829  254 
1 880  1 829  305 
*Tolerances shall be as follows:  
length: + 25 mm;    
width: +10 mm; and  
thickness: +10 mm  
5.3 Flammability  
When foam is tested in accordance with Annex A,  
a) no specimen shall burn for 3 min or more; and  
b) no specimen shall burn beyond the gauge line.  
5.4 Foam  
5.4.1 The foam shall:  
a) be non -toxic;  
b) be free from objectionable odour;  
c) have surfaces that are smooth and practically free from cuts and tears  
5.4.2 The structure of the foam used in the mattress shall be uniform in appearance.  
5.4.3 The foam may be presented in form of full foam or trimmed blocks, slabs, laminated layers, sheets or 
shapes cut from any of these.  
5.4.4  Contacting surfaces of mattress filling parts shall be uniformly and acceptably adhered to one another. 
The adhering edges shall not have any un -adhered length exceeding 10 mm.  DUS 202: 2020  
© UNBS 2020  – All rights reserved  7 
 6 Specific requ irements  
6.1 Flexible polyurethane mattresses  
6.1.1  Polyether foam  
6.1.1.1  The density of polyether foam mattresses, when determined in accordance with US ISO 845 , 
shall be wi thin the limits given in Table 3 . 
6.1.1.2  The hardness factor for mattresses, when determined in accordance with US ISO 2439 , shall 
conform to the limits in Table 3.  
6.1.1.3 The top skin mattress shall  
a) have a hard skin on one side, consisting of a single piece formed through the chemical process of 
foaming  with no sign of bondage or jo ints. 
b) have a minimum density of 24 kg/m3 
c) be practically free from cracks.  
6.1.2  Polyester foam  
The density of polyester foam when determined in accordance with US ISO 845 and its hardness factor when 
determined in accordance with US ISO 2439, shall be with in the appropriate limits given in Table 3  
6.1.3  Reconstituted foam  
6.1.3.1  The density of reconstituted  foam when determined in accordance with US ISO 845 and its 
hardness factor when determined in accordance with US ISO 2439, shall be within the appropri ate limits given 
in Table 3  
6.1.3.2  The chip structure shall be acceptably uniform, and the largest dimension of any void between the 
chips shall not exceed 3 mm . 
6.1.3.3   The upper and lower filling parts of a reconstituted foam shall be of a thickness no t less than 25 
mm.  
6.1.3.4  The centre filling part of a reconstituted foam shall be a thickness not less than 75 mm.  
Table 3 — Physical properties of Flexible polyurethane mattresses  
Parameter  Requirement  Test method  Polyether  Polyester  Reconstituted  
Density kg/m3 19.5 – 48.1 21 – 37.1 56 - 160 US ISO 845  
Hardness factor  0.9 – 6.3 17 - 30 7 - 77 US ISO 2439  
Compression set, %, max.  12 17.5 25 US ISO 1856  
Tensile 
strength  i) Original, kPa, min  69 80 40 
 
 
 
US ISO 1798  ii) After heat aging, 
retentio n of original, 
%, min  80 80 40 
iii) After humid 
aging, retention of 
original, %, min.  80 80 40 
Elongation at 
break  i) Original, kPa, min.  100 200 50 
ii) After heat aging, 
retention of original, 
%, min.   40 80 50  
8 © UNBS 2020  – All rights reserved  
 iii) After humid 
aging, retentio n of 
original, %, min.  40 80 50 
Tear resistance, N/mm of width, min  0.219  0.263  0.09 US ISO 8067  
Permanent 
 resistan
ce to 
solvents  i) Visible 
deterioration (all 
solvents)  * Nil Nil Nil 
 
 
Annex B  ii) Swelling, %   Nil Nil Nil 
iii) Tensile  strength,  
retention of original, 
%, min  90 80  
Fatigue 
resistance  Retention of 
hardness factor, %, 
min  60  80 
US ISO 3385  
Loss in height, %, 
min  5 5 5 
*  A change in colour shall not be construed as evidence of deterioration  
6.2 Expanded Polyethylene Mattr esses  
The density of polyester foam when determined in accordance with US ISO 845 and its hardness factor when 
determined in accordance with US ISO 2439, shall be within the appropriate limits given in Table 4  
Table 4 — Physical properties of expanded poly ethylene mattresses  
Parameter  Requirement  Test method  
Density, kg/m3 20-64 US ISO 845  
Tensile Strength, kpa  
Transverse direction  
Machine direction   
176 – 343 
 
245 - 588 US ISO 1798  
Elongation at break, %  
Transverse direction  
Machine direction   
42 – 75 
 
80 - 100 
Compression strength (at 
10% deformation), kpa  4.9 – 19.6  
Compression set (%), max.  10 US ISO 1856  
Tear strength, N/mm, min.  0.147  US ISO 8067  
Water absorption (after 96 
hours at 270C), % by vol.  0.10 – 0.05  
7  Packaging and labelling  
7.1  Packaging  
7.1.1  The foam mattresses shall be covered in clothing (ticking) complying with requirements given in 
5.1.3 .or any other suitable material as agreed between the purchaser and supplier. To avoid deterioration of 
foam mattresses during storage, it shall be kept in well -ventilated rooms otherwise away from direct sunlight  
7.1.2  Mattresses shall be individually wrapped in sealed polyethylene bags or any other suitable material 
that are strong enough to prevent any damage to the contents during stor age and transportation.  
7.1.3  During dispatch, mattresses shall be packed and transported in manner to minimize damage due to 
rough or improper handling.  DUS 202: 2020  
© UNBS 2020  – All rights reserved  9 
 7.2  Labelling  
7.2.1  Ticking material labelling  
7.2.1.1  The following information shall appear in l egible and indelible marking on a stron g, durable label  
on the outside of the ticking or on the ticking of the mattress.  
a) name and physical address of the manufacturer/ importer/ distributor and/ or trade mark if any;  and  
b) country of origin  
7.2.1.2  Mattress dimensions shall be visible  
7.2.2  Foam labelling   
The following information shall appear in legible and indelible marking on an end or on a sleeping surface near 
an end of the foam of the mattress and shall be visible to the purchaser: Top skin mattres ses shall have an 
indelible mark indicating that they are top skin in addition with the following:  
a) manufacturer/ importer/distributor and/or trademark if any;  
b) lot or batch number;  
c) dimensions of the mattress;  
d) type of mattress core; and  
e) country of origin.   
8  Sampling  
To test the compliance of the foam mattresses to the requirements of this standard, samples shall be taken 
according to the sampling plan given in Table 5.  
Table 5 — Sampling  plan 
Number of mattresses in the lot  Number of samples  to be selec ted 
2 - 8 2 
9 - 15 3 
16 - 25 5 
26 - 50 8 
51 – 90 13 
91 - 150 20 
8.2  Compliance with the specification  
The lot shall be deemed to comply with the specification if after inspection and testing of the samples taken in 
accordance with Clauses 5 and 6, no defective is found.   
10 © UNBS 2020  – All rights reserved  
 Annex  A 
(normative)  
 
Flammability  
A.1 Apparatus  
An apparatus as shown schematically in Figure A.1 and consisting of a heat -resistant glass tube (chimney) in 
which a test specimen can be mounted, the base of the tube being connected  to metered supplies of oxygen 
and nitrogen. The glass tube shall have a diameter of at least 75 mm and a height of at least 450 mm, and 
shall have at its base a bed of glass beads (or other inert particles) that will mix and distribute the incoming 
gases.  The tube shall also contain a clamp that is capable of holding a test specimen (vertically) that the top of 
the specimen is at least 100 mm below the top of the tube.  
The oxygen and nitrogen used shall be of commercial grade (or better) and shall be supp lied to the base of 
the glass tube through individual metering devices that enable the volumetric flow of each gas to be measured 
with an accuracy of 1 % or better.  
A.2 Test specimens  
From the appropriate slab [see 6.1b)] cut five specimens each of size 12.5 mm + 0.5 mm x 12.5 mm + 0.5 mm 
x 130 mm and draw a gauge line across each specimen 75 mm from the end that is to be positioned 
uppermost in the apparatus.  
A.3 Procedure  
Clamp a test specimen in the holder of the apparatus so that it is held vertical ly in the centre of the glass 
chimney. Open the valves of the gas cylinders and adjust the flow so that the oxygen content of the gas 
mixture is 20 % + 0.2 % and that the flow rate up the glass chimney (as calculated from the volumetric flow 
rate divided b y the cross -sectional area of the chimney) is 40 % + 10 % mm/s. Allow the gas to flow for at 
least 30 s and then, using a small gas flame at the end of a tube, ignite the test specimen so that the whole of 
the upper surface is burning. Note whether the spe cimen burns for 3 min or longer and if not, whether or not 
the specimen has burned to below the 75 mm gauge line. Repeat the test with the remaining four specimens.  
 
Figure A.1 — General arrangement of flammability test apparatus  DUS 202: 2020  
© UNBS 2020  – All rights reserved  11 
 Annex  B 
(normative)  
 
Permanent resistance to solvents  
B.1 Apparatus  
B.1.1 Container , glass container large enough to allow complete immersion, without bending of a test 
specimen  
B.1.2 Scoop , flat wire gauze scoop  
B.1.3 Sinker , wire gauze sinker  
B.1.4 Glass , square of plate glass  
B.1.5 Equipment for measuring dimensions , as in US ISO 1923  
B.2 Reagents  
B.2.1 Petrol, c omplying with the requirements of US EAS 158  
B.2.2 Light -naphtha  
B.2.3 Denatured alcohol  
B.2.4 Trichloroethyl ene 
B.3 Test specimen  
From the appropriate slab (see 6.1 b)), cut four specimens each of size at least 150 mm x 150 mm and of 
thickness approximately 10 mm.  
B.4 Procedure  
Measure the thickness, length, and width of a specimen using US ISO 1923, and imme rse it in one of the 
reagents in the container ensuring that it is totally submerged by covering it with the wire gauze sinker. After 
30 min, remove the sinker and, using the scoop, remove the specimen, and allow it to drain in the scoop for 5 
min. Then ca refully transfer the specimen on to the glass plate, ensuring that the specimen is not distorted in 
any way during the transfer.  
Condition the assembly generally as in 7.2, but for at least 48 h or such longer period as may be necessary to 
ensure complete  removal of the reagent, then re -measure the length, width, and thickness of the specimen 
and, disregarding any change in colour, inspect the specimen for signs of visible deterioration.  
Then determine, as in US ISO 1798, its tensile strength. Repeat the test with the other reagents, using a 
different specimen in each test.  
NOTE: To avoid damage to the specimen, its thickness after immersion may be determined by measuring the total 
thickness of the assembly and deducting the thickness of the glass plate.   
12 © UNBS 2020  – All rights reserved  
 B.5 Calculation and reporting  
For each reagent, calculate the swelling of the sample as follows:  
 
Where,  
a1  is the original area, in square millimetres (mm2) 
a2 is the area after immersion;  
t1 is the original thickness, in millimetres (mm); and  
t2 is the  thickness after immersion, in millimetres (mm).  
 
 DUS 202: 2020  
© UNBS 2020  – All rights reserved  13 
 Bibliography  
[1] ISO ##### -#, General title — Part #: Title of part  
[2] ISO ##### -##:20##, General title — Part ##: Title of part  
 DUS 202: 2020  
© UNBS 2020  – All rights reserved  15 
 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 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 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 stand ard.  
Further particulars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 DUS 202: 2020    
 
ICS 97.140 
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