DRAFT UGANDA STANDARD  
  DUS 202 -1 
First Edition  
2015-mm-dd 
 
 
 Reference number  
DUS 202 -1: 201 5 
© UNBS 201 5  
  
Flexible polyurethane foams  — Part 1: Polyether Type — 
Specifications  
 DUS 202-1: 2015 
ii © UNBS 2015 – 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 ar e 
responsible for its correct application  
© UNBS 200 7  
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, w ithout prior written 
permission from UNBS.  
Requests for permission to reproduce this document should be addressed to  
The Executive Director  
Uganda National Bureau of Standards  
P.O. Box 6329  
Kampala  
Uganda  
Tel: 256 41 4 505 995  
Fax: 256 41 4 286 123  
E-mail: unbs@infocom.co.ug  
Web: www.unbs.go.ug  DUS 202 -1:2015 
© UNBS 201 5 – All rights reserved  iii 
 Contents  Page 
Forewo  
Contents  
1 Scope  ................................ ................................ ................................ ................................ ......................  1 
2 Normative references  ................................ ................................ ................................ ............................  1 
3 Terms and definitions  ................................ ................................ ................................ ...........................  1 
4.  Requirements  ................................ ................................ ................................ ................................ .........  2 
4.1  General  ................................ ................................ ................................ ................................ ...................  2 
4.2  Class and grade  ................................ ................................ ................................ ................................ ..... 3 
4.3 Density and hardness factor  ................................ ................................ ................................ ................  3 
4.4  Colour  ................................ ................................ ................................ ......... Error! Bookmark not defined.  
4.5  Flammability  ................................ ................................ ................................ ................................ ...........  3 
4.6  Cell count  ................................ ................................ ................................ ...Error! Bookmark not defined.  
4.7  Porosity  ................................ ................................ ................................ ......Error! Bookmark not defined.  
4.8  Other physical properties  ................................ ................................ ................................ .....................  3 
3.9  Shape and dimensions  ................................ ................................ ................................ .........................  1 
4  Packing and Labeling ................................ ................................ ................................ ............................  1 
4.1  Packing  ................................ ................................ ................................ ................................ ...................  1 
4.2  Labeling  ................................ ................................ ................................ ................................ ..................  1 
5  Sampling  ................................ ................................ ................................ ................................ ................  1 
5.2  Compliance with the specification  ................................ ................................ ................................ ...... 2 
6  Inspection and test methods  ................................ ................................ ................................ ...............  2 
6.1  Inspection  ................................ ................................ ................................ ................................ ...............  2 
6.2  Conditioning  ................................ ................................ ................................ ................................ ..........  2 
6.3  Preparation of test samples and test specimen  ................................ ................................ .................  2 
A.1  Apparatus  ................................ ................................ ................................ ...Error! Bookmark not defined.  
A.1.1  Metre rule  ................................ ................................ ................................ ...Error! Bookmark not defined.  
A.1.2  Micrometer  ................................ ................................ ................................ .Error! Bookmark not defined.  
A.2  Procedure  ................................ ................................ ................................ ...Error! Bookmark not d efined.  
B.1  Apparatus  ................................ ................................ ................................ ...Error! Bookmark not defined.  
B.1.1  Balance  ................................ ................................ ................................ .......Error! Bookmark not defined.  
B.1.2  Measurement  ................................ ................................ ............................. Error! Bookmark not defined.  
B.2  Test specimen  ................................ ................................ ............................ Error! Bookmark not defined.  
B.3  Procedure  ................................ ................................ ................................ ...Error! Bookmark not defined.  
B.4  Calculation  ................................ ................................ ................................ .Error! Bookmark not defined.  
C.1  Apparatus  ................................ ................................ ................................ ...Error! Bookmark not defined.  
C.1.1  Jig ................................ ................................ ................................ ................ Error! Bookmark not defined.  
C1.2  Oven  ................................ ................................ ................................ ............ Error! Bookmark not defin ed. 
C.2  Test specimens  ................................ ................................ .......................... Error! Bookmark not defined.  
C.3  Procedure  ................................ ................................ ................................ ...Error! Bookmark not defined.  
C.4  Calculation  ................................ ................................ ................................ .Error! Bookmark not defined.  
D.1  Apparatus  ................................ ................................ ................................ ...Error! Bookmark not defined.  
D.2  Test specimen  ................................ ................................ ............................ Error! Bookmark not defined.  
D.3  Procedure  ................................ ................................ ................................ ...Error! Bookmark not defined.  
E.1  Apparatus  ................................ ................................ ................................ ...Error! Bookmark not defined.  
E.2  Test specimens  ................................ ................................ .......................... Error! Bookmark not defined.  
E.3  Procedure  ................................ ................................ ................................ ...Error! Bookmark not defined.  DUS 202-1: 2015 
iv © UNBS 2015 – All rights reserved  
 E.4  Calculations  ................................ ................................ ...............................  Error! Bookmark not defined.  
F.1  Apparatus  ................................ ................................ ................................ .. Error! Bookmark not defined.  
F.1.1  Tensile -strength testing machine  ................................ ...........................  Error! Bookmark not defined.  
F.1.2  Micrometer  ................................ ................................ ................................ . Error! Bookmark not defined.  
F.2  Test specimens  ................................ ................................ .........................  Error! Bookmark not defined.  
F.3  Procedure  ................................ ................................ ................................ .. Error! Bookmark not defined.  
F.4  Calculation  ................................ ................................ ................................ . Error! Bookmark not defined.  
K.1  Apparatus  ................................ ................................ ................................ .. Error! Bookmark not defined.  
K.1.1  Hardness factor apparatus  ................................ ................................ ...... Error! Bookmark not defined.  
K.1.2  Flexing machine  ................................ ................................ ........................  Error ! Bookmark not defined.  
K.1.3  Metre  ................................ ................................ ................................ ..........  Error! Bookmark not defined.  
K.2  Test specimen  ................................ ................................ ...........................  Error! Bookmark not defined.  
K.3  Procedure  ................................ ................................ ................................ .. Error! Bookmark not defined.  
K.4  Calculation  ................................ ................................ ................................ . Error! Bookmark not defined.  
L.1  Apparatus  ................................ ................................ ................................ ................................ ............... 8 
L.1.1  Container  ................................ ................................ ................................ ................................ ................ 8 
L.1.2  Scoop  ................................ ................................ ................................ ................................ ...................... 8 
L.1.3  Sinker  ................................ ................................ ................................ ................................ ...................... 8 
L.1.4  Glass  ................................ ................................ ................................ ................................ ....................... 8 
L.1.5  Meas uring equipment  ................................ ................................ ................................ ............................ 8 
L.2  Reagents  ................................ ................................ ................................ ................................ ................. 8 
L.2.2  Light -naphtha . ................................ ................................ ................................ ................................ ........ 8 
L.2.3  Denatured alcohol ................................. ................................ ................................ ................................ .8 
L.2.4  Trichloroethylene . ................................ ................................ ................................ ................................ ..8 
L.3  Test specimen  ................................ ................................ ................................ ................................ ........ 8 
L.4  Procedure  ................................ ................................ ................................ ................................ ............... 8 
L.5   Calculation and reporting  ................................ ................................ ................................ .................... 9 
M.1  Apparatus  ................................ ................................ ................................ .. Error! Bookmark not defined.  
M.2  Test specimens  ................................ ................................ .........................  Error! Bookmark not defined.  
M.3  Procedure  ................................ ................................ ................................ .. Error! Bookmark not defined.  
N.1  Apparatus  ................................ ................................ ................................ .. Error! Bookmark not defi ned.  
N.2  Test specimens  ................................ ................................ .........................  Error! Bookmark not defined.  
N.3  Procedure  ................................ ................................ ................................ .. Error! Bookmark not defined.  
 
rd v 
 DUS 202 -1:2015 
© UNBS 201 5 – All rights reserved  v 
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal  under the Ministry of Tourism, Trade and 
Industry established under Cap 327 , of the Laws of Uganda.  UNBS is mandated to co -ordinate the 
elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point  for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agreements of the World Trade Organisation (WTO).  
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a given field or area and consists of representatives of 
consumers, traders, academicians, manufacturers, government and other stakeholders.  
Draft Uganda Standards adopted by the Technical Committee are  widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
Committee membership  
 
 DUS 202-1: 201 5 
© UNBS 2015 – All rights reserved  1 
 Flexible polyurethane  foams— Part 1: Polyether Type — 
Specifications  
1 Scope  
This draft Ugandan Standard specifies  requirements  and test methods  for seven classes (based on density) of 
flexible polyurethane foams of the poly ether type, in the form of block s, slabs, sheets, and shapes cut from 
these. Each class is sub -divided, according to the hardness of the foam, into at least four grades.  
2 Normative references  
The following referenced documents are indispensable for the application 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.  
FDUS ISO 1798, Flexible cellular polymeric materials — Determination of tensile strength and elongat ion at 
break  
FDUS ISO 1856, Flexible cellular polymeric materials — Determination of compression set  
FDUS ISO 1923, Cellular plastics and rubbers — Determination of linear dimensions  
FDUS ISO 23529, Rubber – General procedures for preparing and conditionin g test pieces for physical test 
methods . 
FDUS ISO 2439:2008, Flexible cellular polymeric materials — Determination of hardness (indentation 
technique)  
FDUS ISO 2440, Flexible and rigid cellular polymeric materials — accelerated ageing tests  
FDUS ISO 3385, Flexible cellular polymeric materials — Determination of fatigue by constant -load pounding  
FDUS ISO 8067:2008 F lexible cellular polymeric materials -- Determination of tear strength  
FDUS ISO 8307, Flexible cellular polymeric materials — Determination of re silience by ball rebound  
US ISO 845, Cellular plastics and rubbers — Determination of apparent density  
3 Terms and definitions  
For the purposes of this standard, the following terms and definitions shall apply  
3.1 
block  
a mass of polyurethane foam formed by a free -rising foam process, in its original form prior to conversion  
3.2 
defective  
a foam that fails in one or more respects to comply with the relevant requirements of the specification  DUS 202-1: 2015 
2 © UNBS 2015 – All rights reserved  
 3.3 
polyurethane foam  
foam in which the polyol component is a  polyether  It is a cellular material produced by the reaction of the  
polyol with an organic isocyanate in the presence of water and that may include catalysts, surface active  
agents, auxiliary blowing agents, fillers, plasticizers, colourants and any other additives that  do not alter the 
properties of the foam.  
3.4 
lot 
not less than 1 m3 and not more than 100 m3 of foam of the same class, grade, and nominal dimensions,  from 
one manufacturer, submitted at any one time for inspection and testing  
3.5 
linear dimensi on 
linear measurements of a specimen in different directions expressed in millimeters  
3.6 
density  
the mass per unit volume of the foam specimen at 23 ± 2°C expressed in kg/m3 
3.7 
tensile strength  
the stress at the breaking point of a specimen expressed in kPa or N/m2 
3.8 
tensile stress  
the stress at predetermined elongation of a specimen expressed in kPa or N/m2 
3.9 
ultimate elongation (elongation at break)  
the percentage strain produced in a specimen stretched to its breaking point  
3.10 
hardness number  
it is stated in the form of grading and is numerically equal to the compressive stress which is necessary to  
penetrate the specimen without puncture to a specified depth or deflection expressed as the load ( N or kPa ) 
per unit area of compression ( m2). Hardnes s number at 40 % or 50 % deflection on specific thickness of  
sample is also referred to as hardness index  
3.11 
indentation hardness index  
the load required to produce a depression of 40 % of initial thickness of the sample  
3.12 
load quotient (indentation h ardness characteristic)  
the ratios of the forces required to obtain the indentations of 25 % and 65 % to the force required to obtain the indentation  
of 40 %.  
4.  Requirements  
4.1  General  
Foam shall be polyether foam, shall be non -toxic, and shall be free  from objectionable odour. The cell 
structure shall be such that it is acceptable and in the cases of trimmed blocks, slabs, sheets, and shapes cut 
from any of these, the surfaces shall be smooth and free from cuts, tears, and skins.  DUS 202-1: 201 5 
© UNBS 2015 – All rights reserved  3 
 4.2  Class and grade  
The class and the grade of foam shall be one of the combinations given in Table 1.  
Table 1 — Classes and grades of foam  
Class No  Grade No  Grade No  Grade No  Grade No  Grade No  Grade No  
20 6 9 12 16 - - 
23 6 9 12 16 20 24 
26 6 9 12 16 20 24 
30 6 9 12 16 20 24 
36 - 9 12 16 20 24 
44 - 9 12 16 20 24 
48 - - 12 16 20 24 
 
4.3 Density and hardness factor  
The density of a foam and its hardness factor determined in accordance with 7.4, Table 6  shall be within the 
appropriate limits given in Table 2.  
4.4  Flamma bility  
When foam is tested in accordance with Annex B, 
a) no specimen shall burn for 3 min utes or more; and  
b) no specimen shall burn beyond the gauge line.  
4.5  Other physical properties  
When tested in accordance with the relevant methods given in the Table 6 , foam shall comply with the  
requirements given in Table 3 appropriate to the class and grade of the foam.  
 
 DUS 202-1: 2015 
4 © UNBS 2015 – All rights reserved  
 Table 2 — Density and hardness factor  
 
 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 
Class  Density, 
kg/m3 Grade  
6 9 12 16 20 24 
Hardness factor  
Min. Max.  Min. Max.  Min. Max.  Min. Max.  Min. Max.  Min. Max.  Min. Max.  
20 19.5 21.0 0.9 1.8 1.8 2.7 2.7 3.6 3.6 4.5 - - - - 
23 21.1 24.0 0.9 1.8 1.8 2.7 2.7 3.6 3.6 4.5 4.5 5.4 5.4 6.3 
26 24.1 27.0 0.9 1.8 1.8 2.7 2.7 3.6 3.6 4.5 4.5 5.4 5.4 6.3 
30 27.1 32.0 0.9 1.8 1.8 2.7 2.7 3.6 3.6 4.5 4.5 5.4 5.4 6.3 
36 32.1 40.0 - - 1.8 2.7 2.7 3.6 3.6 4.5 4.5 5.4 5.4 6.3 
44 40.1 48.0 - - 1.8 2.7 2.7 3.6 3.6 4.5 4.5 5.4 5.4 6.3 
48 48.1 - - - - - 2.7 3.6 3.6 4.5 4.5 5.4 5.4 6.3 DUS 202-1: 201 5 
© UNBS 2015 – All rights reserved  1 
  
Table 3 — other  physical properties  
1 2 3 4 5 6 7 8 9 10 11 12 
Property  Class  
20 23 
Grade  
6 9 12 16 6 9 12 16 20 24 
Compression set, %, max.  12 12 12 12 10 10 10 10 10 10 
Tensile Properties  
a) Tensile strength  i) Original, kPa, min.  69 69 69 69 69 83 83 83 83 83 
ii) After heat aging, retenti on of 
original, %, min.  80 80 80 80 80 80 80 80 80 80 
iii) After humid aging, retention of 
original, %, min.  80 80 80 80 80 80 80 80 80 80 
b) Elongation at break  i) Original, kPa, min.  100 100 100 100 100 100 100 100 100 100 
ii) After heat aging, retention of 
origin al, %, min.  40 40 40 40 40 40 40 40 40 40 
iii) After humid aging, retention of 
original, %, min.  40 40 40 40 40 40 40 40 40 40 
Tear resistance, N/mm of width, min.   0.219  0.263  0.263  0.263  0.263  0.350  0.350  0.5 0.350  0.350  
Permanent resistance to solvents  i) visible deterioration (all solvents)  Nil          
ii) swelling, %  Nil          
iii) Tensile  strength, retention of 
original, %, min  90 90 90 90 90 90 90 90 90 90 
Fatigue resistance  i) Retention of hardness factor, %, 
min 60 60 60 60 70 70 70 70 70 70 
 ii) Loss in he ight, %, min  5 5 5 5 4 4 4 4 4 4 
Note: A change in colour shall not be construed as evidence of deterioration  DUS 202-1: 2015 
2 © UNBS 2015 – All rights reserved  
 Table 3 (continued)  
1 2 3 4 5 6 7 8 
Property  Class  
26 
Grade  
6 9 12 16 20 24 
Compression set, %, max.  10 10 10 10 10 10 
Tensile Proper ties 
Tensile strength  Original, kPa, min.  69 83 83 83 83 83 
After heat aging, retention of original, %, 
min. 80 80 80 80 80 80 
After humid aging, retention of original, %, 
min. 80 80 80 80 80 80 
Elongation at break  Original, kPa, min.  100 100 100 100 100 100 
After heat aging, retention of original, %, 
min. 40 40 40 40 40 40 
After humid aging, retention of original, %, 
min. 40 40 40 40 40 40 
Tear resistance, N/mm of width, min.   0.263  0.350  0.350  0.350  0.350  0.350  
Permanent resistance to solvents  visible deterioration (all solvents)  Nil      
swelling, %  Nil      
Tensile  strength, retention of original, %, 
min 90 90 90 90 90 90 
Fatigue resistance  Retention of hardness factor, %, min  75 75 75 75 75 75 
 Loss in height, %, min  3 3 3 3 3 3 
 
Table 3 (continued)  DUS 202-1: 201 5 
© UNBS 2015 – All rights reserved  3 
 1 2 3 4 5 6 7 8 9 10 11 12 13 
Property   Class  
30 36 
Grade  
6 9 12 16 20 24 9 12 16 20 24 
Compression set, %, max.   8 8 8 8 8 6 6 6 6 6 
Tensile Properties  
Tensile strength  Original, kPa, min.  69 83 83 83 97 97 69 69 83 97 97 
After  heat aging, retention of original, 
%, min.  80 80 80 80 80 80 80 80 80 80 80 
After humid aging, retention of 
original, %, min.  80 80 80 80 80 80 80 80 80 80 80 
Elongation at break  Original, kPa, min.  100 100 100 100 100 100 100 100 100 100 100 
After h eat aging, retention of original, 
%, min.  40 40 40 40 40 40 40 40 40 40 40 
After humid aging, retention of 
original, %, min.  40 40 40 40 40 40 40 40 40 40 40 
Tear resistance, N/mm of width, min.   0.263  0.350  0.350  0.350  0.350  0.350  0.350  0.350  0.350  0.350 0.350  
Permanent resistance to solvents  visible deterioration (all solvents)      Nil       
swelling, %      Nil       
Tensile  strength, retention of original, 
%, min  90 90 90 90 90 90 90 90 90 90 90 
Fatigue resistance  Retention of hardness factor, %, min  77.5 77.5 77.5 77.5 77.5  80 80 80 80 80 
 Loss in height, %, min  2.5 2.5 2.5 2.5 2.5  2 2 2 2 2 
 
 
 DUS 202-1: 2015 
4 © UNBS 2015 – All rights reserved  
 Table 3 (continued)  
1 2 3 4 5 6 7 8 9 10 11 12 
Property  Class  
44 48 
Grade  
9 12 16 20 24 12 16 20 24 
Compression set, %, max.  5 5 5 5 5 4 4 4 4 
Tensile Properties  
Tensile strength  Original, kPa, min.  69 69 83 97 97 83 97 118 118 
After heat aging, retention of original, 
%, min.  80 80 80 80 80 80 80 80 80 
After humid aging, retention of 
original, %, min.  80 80 80 80 80 80 80 80 80 
Elongati on at break  Original, kPa, min.  100 100 100 100 100 100 100 100 100 
After heat aging, retention of original, 
%, min.  40 40 40 40 40 40 40 40 40 
After humid aging, retention of 
original, %, min.  40 40 40 40 40 40 40 40 40 
Tear resistance, N/mm of width , min.   0.263 0.263 0.350  0.350  0.350  0.263 0.350  0.350  0.350  
Permanent resistance to solvents  visible deterioration (all solvents)     Nil      
swelling, %     Nil      
Tensile  strength, retention of original, 
%, min  90 90 90 90 90 90 90 90 90 
Fatigu e resistance  Retention of hardness factor, %, min  82.5 82.5 82.5 82.5 82.5 85 85 85 85 
 Loss in height, %, min  2 2 2 2 2 1.5 1.5 1.5 1.5 DUS 202-1: 201 5 
© UNBS 2015 – All rights reserved  1 
  
4.6  Shape and dimensions  
The foam shall be supplied in the form of blocks, trimmed blocks, slabs or sheets cut fr om trimmed blocks, or  
other shapes cut from any of these forms, and the actual dimensions, measur ed in accordance with Table 6  
shall not differ from the nominal values by more than the appropriate tolerances given in Table 4.  
Table 4 — Tolerances on dimens ions (other than of blocks)  
 Length and width  Thickness  
D ≤ 25   0     +3  
25 < D ≤ 150  0 + 6.5 0 + 4.8 
151 < D ≤ 300  0 + 6.5  0 + 6.5  
301 < D ≤ 600  0 + 12.5  0 + 12.5  
601 < D ≤ 1000  0 + 20 0 + 20 
1001  < D ≤ 1500  0 + 30 0 + 30 
1501  < D ≤ 200 0 0 + 40 0 + 42 
D > 2000  0 + 45 0 + 45 
 
5 Packing and Labeling  
5.1  Packing  
The foam shall be so packed that it is protected from dirt, gross distortion and nicking during normal transport  
and storage.  
5.2  Labeling  
The following information shall appear in legible  and durable marking on the outside of each package on  each 
piece of foam:  
a) name and address of manufacturer;  
b) lot or batch number;  
c) dimensions;  
d) class and grade of foam;  
e)   country of origin.  
6  Sampling  
6.1  The following sampling procedure shall be applied i n determining whether a lot complies with the  
requirements of the specification. The samples so taken shall be deemed to represent the lot.  Take at random 
from the lot the number of samples shown in Column 2 of Table 5 relative to the appropriate  lot size shown in 
Column 1. Each sample shall consist of the following:  
a) For inspection ― A complete piece.  DUS 202-1: 2015 
2 © UNBS 2015 – All rights reserved  
 b) For testing ― Pieces of total volume at least 0.01 m3. 
Table 5 — Sampling  
Size of lot, L, m3 Number of samples  
L ≤ 8  2 
8 < L ≤ 15  3 
15 < L ≤ 25  5 
25 < L ≤ 50  8 
50 < L ≤ 100  13 
 
6.2  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 Clause 6 , no defective is found.  
7  Inspection and methods  of test  
7.1  Inspection  
Visually examine and measure dimension of (using the method given in Table 6 ) the samples ( see 6.1 (a)  for 
compliance with the requirements of 4.1, 4.6 and 5 . 
7.2  Conditioning  
Before testing, maintain all specimens for at least 16 h in an atmosphere having a relative humidity of  65 % ± 
2 % and a t emperature of 23 °C ± 2 °C.  
7.3  Preparation of test samples and test specimen  
7.3.1  From each sample, obtain as follows, a test sample for each test given in the Annexes.  Using a 
fine-toothed saw or rotary slicer (but not a heated wire), cut across the d irection of rise of the foam  (as 
determined by microscopical examination) a slab of suitable size and of the same thickness as that of the  test 
specimens required for the relevant test, and that is free from skin.  
NOTE :  Slabs of the following thickness ar e required: 12.5 mm, 25 mm, 50 mm.  
7.3.2  When cutt ing the test specimens for density and compression set , use a die, a saw, or a knife, as  
appropriate, and ensure that the top and bottom surfaces of each specimen are flat and parallel to each  other, 
that the sides are vertical, and that the test specimens are free from skin.  
 
 
 
 
 DUS 202-1: 201 5 
© UNBS 2015 – All rights reserved  3 
 7.4 Methods of test  
Use the relevant methods given in Table 6  
Table 6: Properties and methods of test  
Property  Test methods  
Density  US ISO 845  
Hardness  factor   ISO 2439:2008, 7 .3 method A  
Flammability  Annex B  
Compression set  ISO 1856  
Tensile strength and elongation at break  ISO 1793  
Fatigue resistance  ISO 3385  
Tear resistance  ISO 8067  
Resistance to solvent  Annex A  
Dimensions  ISO 1923  
 DUS 202-1: 2015 
4 © UNBS 2015 – All rights reserved  
 Annex A  
(informative)  
 
Advice to us ers 
The durability of a foam in a particular application and the comfort provided, depends on the use of the correct 
class of foam. The recommended class(es) of foam for each t ype of duty are given in Table A .1. 
Foams of class numbers lower than the lowest  of the applicable numbers shown in Column 3 are not suitable, 
but those of higher class numbers may be used if desired.  
Table A.1 — Classes of foam suitable for various types of duty  
1 2 3 
Type of duty  Application examples  Class of foam recommended  
Light  Padding; scatter cushions; pillows  17; 20  
Light duty mattresses  
Light duty mattress toppers  
Medium  Backs and armrests for private and 
commercial vehicles  23; 26  
Backs and armrests for domestic 
furniture  
Medium duty mattresses  
Medium duty mattress toppers  
Heavy  Backs and armrests for cinema and 
theatre furniture  30 
Backs and armrests for contract 
furniture  
Backs and armrests for public 
transport  
Seats for private and commercial 
vehicles  
Seats for domestic furniture  
Heavy du ty mattresses  
Heavy duty mattress toppers  
Super heavy  Seats for public transport  36; 44; 48  
Seats for cinema and theatre furniture  
Seats for contract furniture  
 
 
 DUS 202-1: 201 5 
© UNBS 2015 – All rights reserved  5 
 Annex B 
(normative)  
 
Flammability  
H.1  Apparatus  
An apparatus as shown schematic ally in Figure G.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 to p 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 supplied 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.  
H.2  Test specimens  
From the appropriate slab ( see 5.1b)) 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.  
H.3  Procedure  
Clamp a test specimen in the holder of the apparatus so that it is held vertically 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 by 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 specimen 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 H.1 — General arrangement of flammability test apparatus  
 
 DUS 202-1: 2015 
6 © UNBS 2015 – All rights reserved  
 Annex C 
(normative)  
 
Tensile properties after heat aging  
 
Determine as in Annex F the tensile strength and elongation at break of five specimens that have been heat  
aged for 22 h in an air oven at 140 ºC + 1 ºC, and calculate the resistance to heat aging of the sample as  
Resistance to humid aging, retention of original, %, = 
100property tensileof value originalsample agedof property tensiletheof value  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 DUS 202-1: 201 5 
© UNBS 2015 – All rights reserved  7 
 Annex D  
(normative)  
 
Tensile properties after humid aging  
Determine as in Annex F the tensile strength and elongation at break of five specimens that have been humid 
aged in dry steam at 105 ºC + 1 ºC for 3 h, dried at 70 ºC to constant mass, and condit ioned as in 6.2. Then 
calculate the resistance to humid aging of the sample as follows:  
Resistance to humid aging, retention of original, =
100property tensileof value originalsample agedof property tensiletheof value  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 DUS 202-1: 2015 
8 © UNBS 2015 – All rights reserved  
 Annex E  
(normative)  
 
Permanent resistance to solvents  
L.1  Apparatus  
L.1.1  Container  
a glass container large enough to allow complete immersion, without bending of a test  specimen.  
L.1.2  Scoop  
a flat wire gauze scoop.  
L.1.3  Sinker  
a wire gauze sinker.  
L.1.4  Glass  
a square of plate glass.  
L.1.5  Measuring e quipment  
as in Clause A.1.  
L.2  Reagents  
L.2.1   Petrol  
complying with the requirements of EAS US 158:2012  
L.2.2  Light -naphtha . 
L.2.3  Denatured alcohol . 
L.2.4  Trichloroethylene . 
L.3  Test specimen  
From the appropriate slab (see 5.1 b)), cut four specimen s each of size at least 150 mm x 150 mm and of  
thickness approximately 10 mm .  
L.4  Procedure  
Measure, as in Clause A.2 the thickness, length, and width of a specimen, and immerse it in one of the  
reagents in the container ensuring that it is totally subme rged by covering it with the wire gauze sinker. After  DUS 202-1: 201 5 
© UNBS 2015 – All rights reserved  9 
 30 min, remove the sinker and, using the scoop, remove the specimen, and allow it to drain in the scoop for  5 
min. Then carefully transfer the specimen on to the glass plate, ensuring tha t the specimen is not distorted in 
any way during the transfer.  
Condition the assembly generally as in 6.2, but for at least 48 h or such lo nger period as may be necessary to 
ensure complete removal of the reagent, then re -measure the leng th, width, and thickness of the specimen 
and, disregarding any change in colour, inspect the specimen for signs of visible deterioration.  
Then determine, as in Annex F, 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.  
L.5   Calculation and reporting  
For each reagent, calculate the swelling of the sample as follows:  
Swelling, % = 
100
1111 22
tata ta  
where,  
a1 = original area, in mm 2; 
a2 = area after immersion;  
t1= original thickness, in mm;  
t2 = thickness after immersion, in mm.  
 
 
 
 
 
 
 
 
 
 
 
 
 DUS 202-1: 2015 
10 © UNBS 2015 – All rights reserved  
 Bibliography  
[1] KS 376 -0: 2013 Flexible polyurethane (polyet her) foams — Specification Part 0: General requirements  
[2] SABS 640: 1992 Specification for flexible polyurethane foams  
. DUS 202-1: 201 5 
© UNBS 2015 – All rights reserved  11 
 Certification marking  
Products that conform to Uganda standards may be marked with Uganda National Bureau of Standards 
(UNBS) Certif ication 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 N ational 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 standard.  
Further particulars of the terms and conditions of lice nsing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 DUS 202-1: 2015 
2 © UNBS 2015 – All rights reserved