KENYA STANDARD         DKS  1620:2020  
ICS 61.060  
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Bathroom slippers — Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
© KEBS 2020  Fifth Edition , 2020  
 
 
  DKS  1620:2020  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ii  © KEBS 2020 — All rights reserved  TECHNICAL COMMITTEE REPRES ENTATION  
 
The following organizations were represented on the Technical Committee:  
 
Kenya Industrial Research and Development Institute (KIRDI)  
Government Chemist  
Kenya Association of Leather Technologists and Scientists  
Bata Shoe Company , PLC  
Umoja Rubber  Products Limited.  
Ministry of Industry, Trade and Cooperative  
Environmental Institute of Kenya  
Pelinks Company  
Kenya Bureau of Standards — Secretariat    
 
 
 
 
REVISION OF KENYA STANDARDS  
 
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed.  Suggestions 
for improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, 
are welcome.  
 
 
 
 
 
 
 
© Kenya Bureau of Standards, 201 8 
 KENYA STANDARD                                            DKS 1620:2020  
ICS 61.060  
© KEBS 2020 — All rights reserved    iii Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 130 of 2001  of the Laws of Kenya, copy right 
subsist s in all Kenya Standards and except as provided under Section 25 of this Act, no Kenya Standard produced by Kenya Bureau of 
Standards may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in  writin g 
from the Managing Director.  
  DKS  1620:2020  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
iv  © KEBS 2020 — All rights reserved   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Bathroom slippers — Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 KENYA STANDARD                                            DKS 1620:2020  
ICS 61.060  
© KEBS 2020 — All rights reserved    v  
 
 
 
 
 
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office: P.O. Box 54974, Nairobi -00200, Tel.: (+254  020) 605490, 602350, Fax: (+254 020)  604031  
E-Mail: info@kebs.org, Web:http://www.kebs.org  
 
Coast Region     Lake Region       Rift Valley Region  
P.O. Box 99376, Mombasa -80100   P.O. Box 2949, Kisumu -40100        P.O. Box 2138, Nakuru -20100  
Tel.: (+254  041) 229563, 230939/40  Tel.: (+254 057) 23549, 22396        Tel.: (+254 051) 210553, 210555  
Fax: (+254  041) 229448    Fax: (+254 057) 21814  
 
 
Foreword  
 
This Kenya Standard was prepared by the Leather and Leather Products Technical Committee under the 
guidance of the Standards Projects Committee, and it is in accordance with the procedures of the Kenya 
Bureau of Standards.  
 
This sta ndard c ancels and replaces KS 1620:2018 , Bathroom slippers  — Specification whic h has been 
technically revised.  
 
 
During the preparation of this standard, refe rence was  made to the following document : 
 
IS 10702, Rubber Hawai  Chappal — Specification . 
 
Acknowledgement is hereby made for the assistance derived from th is source . 
  
KENYA STANDARD            DKS  1620:2020  
 
© KEBS 2020 — All rights reserved    1 Bathroom slippers — Specification  
 
1 Scope  
 
This Kenya Standard specifies  the requirements and methods of test for bathroom slippers, sole made from 
single or combination various expanded composite materials.  
 
2 Normative references  
 
The following referenced documents are indispensable for the application of this standard. For dated 
references, only the edition cited applies. For undated references, the latest edition of the referenced 
document (including any amendments) applies.  
 
KS 1631, Glossary of terms relating to footwear  
 
KS ISO 3376, Leather — Determination of tensile strength and elongation  
 
KS ISO 3377 -1, Leather — Determination of tearing load . 
 
KS ISO 48 -2, Rubber, vulcanized or thermoplastic — Determination of hardness — Part 2: Hardness 
between 10 IRHD and 100 IRHD  
 
KS ISO 16177, Footwear — Resistance to crack initiation and growth — Belt flex method  
 
KS ISO 20871, Footwear — Test methods for outsoles — Abrasion resistance  
 
 
KS ISO 2420, Leather — Physical and mechanical tests — Determination of apparent density and mass per 
unit area  
 
KS ISO 17706, Footw ear — Test methods for uppers —Tensile strength and elongation  
 
 
3 Terms and definition s 
 
For the purposes of this standard, t he definitions given in KS 1631  shall apply.  
 
4 Requirements  
 
4.1 The material shall be polymer of EVA and combinations of which EVA is the most dominant.  
 
4.2 The surface shall be free from blisters, cavities, collapses or blemishes.  The die markings shall be 
neat and clean and the surface shall have reasonably good finish.  
 
4.3 The length and the standard sizes shall be as in Annex A.  
 
4.4 The minimum sole thickness shall be 15 mm for all the sizes.  
 
4.5 The physical requirements for sole and  the strap material shall comply with the values given in 
Tables 1 and 2 respectively.  
   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2  © KEBS 2020 — All rights reserved   
Table 1 — Physical requirements for sole material  
 
SL No.  Characteristic  Requirement   
Test method  
 
i) Density g/cm3 
 0.2 ― 0.5 KS ISO 2420  
ii) Hardness (IRHD)  30 ― 55 KS ISO 48 -2 
iii) Tensile strength (MPa), min.  
 1.0 KS ISO 3376  
iv) Elongation (%), min.  
 50 KS ISO 3376  
v) Tear strength, N, min . 35 KS ISO 3377 -1 
vi) Compression set at constant stress (%), 
max.  35 Annex B  
vii) Flexing resistance :  
 
a) Flexing endurance (Flexing 
cycles), min.  
 
b) Cut growth at the end of 35 000 
cycles at 500 % (mm), max .  
35 000  
 
 
3   
 
 
KS ISO 16177   
 
 
viii) Abrasion loss (cubic mm), max.  1200  KS ISO 20871   
ix) Room temperature shrinkage at 25  2 ˚C 
for two weeks (%), max.  1.0 Annex C  
x) Heat shrinkage for 1 h at 100  ˚C, (%) 
max.  2.0 Annex D  
xi) Water absorption (%), max.  5 Annex E  
xii) Split tear strength (N), min.  35 Annex F 
 
 
Table 2 — Physical requirements for strap  DKS  1620:2020  
© KEBS 2020 — All rights reserved    3  
 
 
5 Packaging  
 
5.1 Each piece shall be packe d with its complementary piece.  
 
5.2 The pieces shall be of the same size and shape (design).  
 
5.3 The pair shall be  packed in a suitable material.  
 
5.4 Each package shall be marked with the following information:  
 
a) name of item;  
 
b) colour  
 
c) batch number;  
 
d)         name or trade mark of the manuf acturer.  
 
e)         country of origin.  
 
 
6 Marking  
 
Slippers shall be indelibly and legibly marked in the outer waist of the sole and the inner face of the straps 
with the following information:  
 
a) size range;  
 
b) name or trade mark of the manufacturer;  
 
 
  SL No.   
Characteristic  
  
Requirement   
Test method  
 PVC Rubber  
i) Tensile strength (MPa), 
min. 5 15 KS ISO 3376  
ii) Elongation (%), min.  150 250  
KS ISO 3376  
iii) Breaking strength (N), min.  
 
a) Stem  
 
b) Toe 
 
c) Heel  
 
180 
 
180 
 
150  
 
180 
 
180 
 
150  
KS ISO 17706  
iv) Pull strength (N), min.  
 
a) Toe end  
 
b) Heel end   
 
100 
 
100  
 
100 
 
100  
Annex G  
Note: In number iii), test piece s to be cut in lengthwise direction only.   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4  © KEBS 2020 — All rights reserved   
Annex A  
(normative)  
 
Table A.1  — Children’s range  
 
Size 
 Minimum  length  
(mm)  
3 126.50  
4 135.00  
5 143.50  
6 152.00  
7 160.50  
8 169.00  
9 177.50  
10 186.00  
11 194.50  
12 203.00  
13 211.00  
 
Table A.2  — Adults’ range  
 
Size 
 Minimum  length  
(mm)  
 
1 220.00  DKS  1620:2020  
© KEBS 2020 — All rights reserved    5 2 220.50  
3 237.00  
4 245.50  
5 254.00  
6 262.00  
7 271.00  
8 279.50  
9 288.00  
10 296.50  
11 305.00  
12 313.50  
13 322.00  
 
   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6  © KEBS 2020 — All rights reserved   
Annex   B 
(normative)  
 
Method for determination of compression set at constant stress  
 
B.1 Apparatus  
 
Consists of two parallel, flat, rigid plates between which the test piece shall be compressed and the means of 
which a load of 140 kg ± 1 kg is applied.  
 
B.2 Test piece  
 
The test pieces shall be three discs of diameter 30 mm ± 0.2 mm of any thickness.  
 
B.3 Procedure  
 
B.3.1 Condition the test pieces at 27 ˚C ± 2˚C and 65 % ± 5 % relative humidity for 24 h.  
 
B.3.2 Measure the initial thickness of each test piece at the cente r using the gauge with part -spherical 
contact.  
 
NOTE  Take the arithmetic mean of three readings as the initial thickness.  
 
B.3.3 Place the three test pieces on parallel plates of the compression apparatus and subject to a 
compression load of 140 kg ± 1 kg for 24 h.  
 
B.3.4 Release the load, remove the test pieces and allow to recover.  
 
B.3.5 After 1 h, measure the thickness and note the arithmetic mean as the final thickness.  
 
B.4 Expression of results  
 DKS  1620:2020  
© KEBS 2020 — All rights reserved    7 Percentage compression set   =   
100
oo1   −
ttt  
Where , 
to is  initial thickness in mm, and  
 
t1  is  final thickness in mm.  
 
 
   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8  © KEBS 2020 — All rights reserved  Annex C 
(normative)  
 
Method for determination of room temperature shrinkage  
 
C.1 Test piece  
 
Cut from the samples, test pieces of minimum dimensions 125 mm x 5 mm x 15 mm, after splitting all the sides 
of the sample.  
 
C.2 Conditioning of the test piece  
 
Condition the test piece at 65 % ± 5 % relative humidity  and 27 ˚C ± 2˚C for at least 24 h prior to testing.  
 
C.3 Number of tests  
 
Carry out tests on at least three test pieces.  
 
C.4 Procedure  
Condition the test piece.  Measure the length of the test piece to the nearest 0.1 mm.  Keep the test piece suitably 
in a closed chamber maintained at 27 ˚C ± 2 ˚C for 2 weeks.  Remove the test piece from the chamber and 
measure its length again.  
 
C.5 Calculation  
 
Calculate the room temperature shrinkage as follows:  
 
Room temperature shrinkage per cent =   
100   LLL
oo−  
Where   
L  is length of the test piece, in mm, before heating, and   
      Lo   is length of the test piece, in mm, after heating for two weeks.  DKS  1620:2020  
© KEBS 2020 — All rights reserved    9  
Annex  D 
(normative)  
Method for determination of heat shrinkage  
 
D.1 Test pieces  
 
Cut test pieces of minimum dimensions 150 mm x 25 mm x 15 mm from post -cured sole by means of a knife.  
 
D.2 Conditioning of test piece  
 
Condition the test piece at 27 ˚C ± 2 ˚C temperature and 65 % ± 5 % relative humidity at least 24 h prior to 
testing.  
 
D.3 Number of tests  
 
Carry out test on at least three test pieces.  
 
D.4 Procedure  
 
Trace the test p iece on  a piece of white paper.  Measure the length of the tes t piece to the nearest 0.1 mm. Keep 
the test piece suitably in an oven (Thermostatically controlled) for 1 h at 100 ˚C ± 1°C.  Take out the piece from 
the oven and cool to ambient temperature. Keep the test piece at room temperature for a minimum 2 h. Trace it 
again on the same paper and measure the length of the test piece on paper.  
 
D.5 Calculation  
 
Calculate the shrinkage as follows:  
 
Shrinkage, per cent =  
100   LLL
01−  
 
Where   
 
L0 is length of the test piece, in mm, before heating, and  
 
L1 is length of test piece, in mm, after heating and  cooling to room temperature.  
 
 
   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
10  © KEBS 2020 — All rights reserved  Annex  E 
(normative)  
 
Method for the determination of water absorption  
 
E.1 Test pieces  
 
Cut three pieces of 5 mm x 5 mm x 5 mm after shrinking all sides of the sample.  
 
E.2 Conditioning  
 
Condition for 24 h prior to testing at 27 ˚C ± 2 ˚C and 65 % ± 5 % relative humidity.  
 
E.3 Procedure  
 
E.3.1 After conditioning the test piece, weigh to the nearest 0.5 mg and immerse in distilled water for a 
period of 24 h at 27 ˚C ± 2 ˚C. 
 
E.3.2 Remove from the water, wipe dry the exposed surfaces with blotting paper.  
 
E.3.3 Weigh the test piece again to the nearest 0.5 mg within 2 min of the removal of the test piece from water.  
 
E.4 Expression of results  
 
Calculate the water absorption as follows:  
 
Water absorption percentage  =  
100 MMM
00−  
Where  
 
M  is mass, in g, of test piece after immersion in water, and  
 
M0 is mass, in g of test piece before immersion in water.  
 
 
 DKS  1620:2020  
© KEBS 2020 — All rights reserved    11 Annex F  
(normative)  
 
Method for the determination of split tear  
 
F.1 Apparatus  
 
Tensile testing equipment with a rate traverse of 75 mm per minute  
 
F.2 Conditioning  
 
 Condition the samples for 24 h prior to testing at 25 ˚C ± 2 ˚C and 65 % ± 5 % relative humidity.  
 
 
F. 3 Test pieces .  
 
After conditioning the test piece , cut three test pieces  of 25 mmx100 mm  along and across the 
direction of the bottom material of a bathroom slipper  or a sheet . Prepare each test piece by 
splitting it with a knife  or any other suitable method  through midway between the top and the 
bottom surfaces for a distance of 30 mm  from on e end to form two  tongues. See Figure below.  
 
    F.4 Procedure  
 
    Clamp one tongue of the test piece on the upper jaw, and the other on the lower jaw.  
    Start the machine and set the rate of separation speed at a constant rate of 75mm per  
     minute.  
 
    F.5 Results  
      
    After the test pieces have separated, note the maximum load and record the arithmetic  
    mean of the three test pieces in Newton (N)  as the split tear strength of the sample.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
12  © KEBS 2020 — All rights reserved   
Dotted line shows knife cut      
 a) Test piece before cut  
  
 
b) Test piece after cut  
NEW  
 
DKS  1620:2020  
© KEBS 2020 — All rights reserved    13 METHOD FOR  
 
 
 
 
 Annex G  
(normative)  
Method for the determination of strength required to pull strap from soling hole at the 
heel and toe end  
G.1 Apparatus  
 
Tensile testing  machine . Tensile testing equipment with a rate traverse of 75 mm per minute  
 
G.4 Test piece preparation  
 
Cut the test piece as shown in the diagram Figure 1, to have test pieces as shown in Figure 2.  For each test, cut  
three test pieces.  
 
G.5 Procedure  
 
Insert on e of the test pieces cut from the bottom material (Figure 1)  in the holding device and clamp as shown  in 
Figure 2 in the  tensile testing machine . Pull until the button comes off, Record the force in Newton (N). Record 
an average of three readings  
 
G.6 Expression of results  
 
G.6.1 The force required to pull button through the hole in the sole.  
 
G.6.2  Malformation occurring to sole during procedure.  
 
G.6.3 Malformation occurring to strap during procedure.  
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
14  © KEBS 2020 — All rights reserved  G.1    G.2  
Figure 1 Figure 2