DKS 1941 – 3: 2017  
 ICS 71.100.70 
   
DRAFT KENYA STANDARD 
 
 
 
 
 
   
 
Scouring compounds for utensil cleaning — 
Specification Part 2: Dishwashing bar 
 
 
 
 
 
 
  
 
 
 
 
 
 
  
 
 
 
  
 
 
JULY 2017 
 
 
 
© KEBS 2017        First Edition 2017 
 
 DKS 1941 – 3: 2017  
ii   
   
               © KEBS 2017 — All rights reserved   
 
  
TECHNICAL COMMITTEE REPRESENTATION 
 
The following organizations were represented on the Technical Committee: 
 
PZ Cussons  Colgate-Palmolive
 
Unilever Kenya Orbit Chemicals Kenya Industrial Research and Development Institute 
Government Chemist’s Department 
University of Nairobi Consumer Information Network 
Pwani Oil Refineries 
Diversey East & Central Africa Colgate Palmolive (E.A) Ltd.Henkel Chemicals 
Reckitt Benckiser  
MEP Chemicals Bidco Oil Refineries 
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, 2017 
  Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 12 of 2001  of the Laws of Kenya, copyrig ht 
subsists in all Kenya Standards and except as provided under Section 26 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 w riting 
from the Managing Director. 
 
  
 KENYA STANDARD  DKS 1941 – 3: 2017 
 ICS 71.100.70  
 © KEBS 2015 — All rights reserved    
   
     iii  
 
 
 
 
 
 
 
Scouring compounds fo r utensil cleaning — 
Specification 
Part 3: Dishwashing bar 
 
 
 
 
  
 
 
  
 
 
 
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-20150 
Tel.: (+254 041) 229563, 230939/40               Tel.: (+254 057) 23549, 22396       Tel.: (+254 051) 210553, 210555 
Fax: (+254 041) 229448   Fax: (+254 057) 21814  
 
 
 
 DKS 1941 – 3: 2017  
iv   
   
               © KEBS 2017 — All rights reserved   
Foreword 
 
This Kenya Standard was developed by the Technical Committee on Surface Active Agents under the 
guideline of the Standards Project Committee, and is in accordance with the procedures of the Kenya 
Bureau of Standards.  
Dishwashing bars are used to remove grease from dishes, pots, pans, glasses and cutlery.  Surfactants and 
builders are the major components of dishwashing bars. Other ingredients (builders) are added to provide a 
variety of functions, such as increasing cleaning performance for specific soils/surfaces, ensuring product 
stability and supplying a unique identity to a product. 
 
Surfactants (surface active agents) are organic chemic als that change the properties of water. By lowering 
the surface tension of water, surfactants enable the clea ning solution to wet a surface so that soil can be 
readily loosened and removed. Surf actants also emulsify oily soils.  Builders enhance and maintain the 
cleaning efficiency of the surfactant. The primary function of builders is to reduce water hardness. Complex 
phosphates and sodium citrate are common builders. Builders can also maintain alkalinity, which assists 
cleaning, especially of acid soils; help keep removed soil and emulsify oily and greasy soils. 
 
During the preparation of this standard, reference was made to the following documents:  
 
KS 1941: Dishwashing paste – Specification IS 6047: Scouring products for utensil cleaning – Specification 
 
Acknowledgement is hereby made for assistance derived from these sources. 
 
 KENYA STANDARD                          DKS 1941 – 3: 2017 
KEBS 2017 — All rights reserved  1 
Scouring compounds for utensil cleaning  — Specification 
Part 3: Dishwashing bar 
 
1 Scope  
This Kenya Standard prescribes the requirements and methods of test for dishwashing bar. 
 
2  Normative references  
 
This Kenya Standard incorporates by dated and undated reference, provisions from other publications.  
These normative references are cited at the appropriate place in the text and the publications are listed  hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply  
to this Kenya Standard only when incorporated in it by amendment or revision. For undated references the  
latest edition of the publication referred to applies.  
KS ISO 456, Surface active agents — Analysis of soaps — Determination of free caustic alkali  
KS ISO 685, Analysis of soap — Determination of alkali content and total fatty matter content  
KS ISO 4315, Surface active agents -- Determination of alkalinity -- Titrimetric method 
KS ISO 2870,  Surface active agents — Detergents — Determi nation of anionic-active matter hydrolysable 
and non-hydrolysable under acid conditions  
KS ISO 2871-1, Surface active agents — Detergents — Determination of cationic-active matter content — 
Part 1: High-molecular-mass cationic-active matter  
KS ISO 2871-2, Surface active agents — Detergents — Determination of cationic-active matter content — 
Part 2: Cationic-active matter of low molecular mass (between 200 and 500) 
KS ISO 672, Soaps — Determination of moisture and volatile matter content — Oven method 
KS ISO 4317, Surface-active agents and detergents — Determination of water content — Karl Fischer 
methods  
KS EAS 814,  Determination of biodegradability of surfactants — Test method  
KS EAS 794, Determination of the microbial inhibition of cosmetic soap bars and liquid hand and body 
washes — Test method  
 
3 R equirements  
 
3.1 General 
 
3.1.1 The bar shall be water-based and shall consist essentially of an abrasive together with a  
surfactant, and may contain alkaline salts. 
 
3.1.2 The bar shall be smooth, and shall be uniformly mixed. It shall not be irritating to the normal skin, and  
it shall not contain ingredients in quantities that are toxic to human beings. 
 3.1.3 When the bar is stored or transported under normal conditions in its original package, no cracking of the 
material shall occur. 
 3.2 Biodegradability  
The dishwashing bar shall pass the biodegra dability test as given in KS EAS 814. 
 3.3 Odour The dishwashing bar, both as received and when dissolved in hot water, shall not have 
objectionable odour. 
3.4 If the dishwashing bar is antibacterial, it shall pass shall pass the antibacterial activity test when 
determined by the method given in KS EAS 794. 
 
3.5 DETAILED REQUIREMENTS .  
In addition to the above requirements, the dishwashing bar shall also comply with the relevant requirements  given in Table 1. DKS 1941 – 3: 2017  
© KEBS 2017 — All rights reserved  2 
Table 1: Detailed requirements 
 
Sl. 
No. Characteristic Requirement Method of test  
1 Free alkali content* (as sodium 
hydroxide) % (m/m), Max. 0.1 KS ISO 456 
2 Total alkalinity* (as sodium 
hydroxide) % (m/m), Max.  12.0 KS ISO 685 
KS ISO 4315 
3 Active detergent*, % (m/m), Min. 8.0 KS ISO 2870 
KS ISO 2871-1 
KS ISO 2871 -2 
4 Water insoluble matter content*, % 
(m/m), Max. 80 Annex D 
5 Moisture and volatile matter 
content*,at  105 ºC % (m/m), Max. 10 KS ISO 672 
KS ISO 4317 
6 Fineness of water insoluble matter 
retained on a 250 µm aperture sieve 
% (m/m), Max. 0.1 
 Annex C 
8 Active (reserve) alkalinity in ml, Max. 20 Annex C 
9 Lather volume, Min. 70  
 *On the dishwashing bar as received 
 
4. Packaging and Marking  4.1 Packing   
 
4.1.1  The dishwashing bar shall be so packed as to prevent  drying out  and contamination of the product. 
 
4.1.2  It shall be packed in containers that are strong enough to withstand normal usage and 
transportation.  
 
4.2 Marking  
Each package and bulk package shall bear in prominent, legible, and indelible marking the following 
information,   
i) Name of the product i.e. dishwashing bar 
 ii) The name and address of the manufacturer and trade mark if any. 
 
iii) Nominal weight of the product at the time of packaging. 
 iv) List of ingredients 
 
v) Name of antibacterial agent used and its level in percentage if the product is antibacterial  
vi) Instructions for use 
 vii) Date of manufacture  
 
viii) Best before date  
ix) In the case of bulk packages, the number of packets.  
 
x) Country of origin  DKS 1941 – 3: 2017  
 © KEBS 2015 — All rights reserved    
   
     3   
Annex D 
Water insoluble matter content of Dishwashing bar  (Metric units) 
 
D.1 Apparatus 
 
Oven,  A drying oven capable of being maintained at 105 ± 5 oC. 
 
D.2 Procedure 
 
Dry the residue and the filter, retained from the dete rmination of alkaline salts (Annex B), in the oven 
maintained at 105 ± 5 oC, cool in a desiccator, and weigh.  Repeat the drying and weighing procedure until 
no further loss in mass occurs. 
 
D.3 Calculation 
 
Water insoluble matter content, % (m/m = 
BA100 
 
where  
A = mass of the residue, g 
  B = mass of the test sample used, g (from Annex B) 
  DKS 1941 – 3: 2017  
© KEBS 2017 — All rights reserved  4Annex E 
 
Volatile matter content of dishwashing bar (Metric units ) 
 
E.1 Apparatus 
 
Oven, A drying oven capable of being maintained at 105 ± 5 oC. 
 
E.2 Procedure 
 
Weigh accurately approximately 5 g of the test sample  into a tared weighing bo ttle.  Dry in the oven 
maintained at 105 ± 5 oC, cool thoroughly in a desiccator, and weigh.  Repeat the drying and weighing 
procedure until the difference between two successive weighings with a 1 h drying period between is not 
more than 3 mg. 
 
E.3 Calculation 
 
Volatile matter content, % (m/m)  = BAB 100) ( 
 
where  
A = mass of the sample after drying, g 
B = mass of the test sample used, g  
 DKS 1941 – 3: 2017  
 © KEBS 2015 — All rights reserved    
   
     5   
Annex F 
 
Fineness of water insoluble matter dishwashing bar (Metric units ) 
 
F.1 Apparatus 
 
F.1.1 Sieves  A nest of two standard sieves, of diameter 200 mm, and of the following nominal aperture 
sizes:  425 µm and 180 µm. 
 F.1.2 Oven  A dying oven capable of being maintained at 105 ± 5 
oC. 
 
F.2. Procedure 
 
F.2.1 Weigh out 50.0 g of the test sample into a beaker and add 200 ml of water.  Heat on a water bath, 
with frequent stirring, until all the soluble salts are dissolved.  
F.2.2 Assemble the nest of sieves in the correct order with the 425 µm aperture sieve at the top and the 
180 µm aperture at the bottom.  Pour the mixture on to the top sieve and transfer the residue quantitatively to this sieve by washing the beaker several times with water. 
 
F.2.3 Using a fine stream of tap water, wash the insoluble matter through the sieves.  Continue this 
washing until the amount of any residue on the top sieve appears to remain constant. 
 
F.2.4 If there is any residue on the top sieve, remove the sieve, stand it in a basin, and continue washing 
the material on it for a further 2 min.  Transfer any furt her material that passes this sieve to the bottom sieve.  
Repeat the washing of the top sieve and the transfer of ma terial until no further material passes through after 
2 min.  
F.2.5 Repeat this procedure on the bottom sieve but discard any material that passes through. 
 
F.2.6 Dry each sieve and its contents in the oven at 105 ± 5 
oC.  Allow them to cool and, using a camel-
hair brush, transfer the contents of each sieve quantitatively to separate tared, glass dishes and determine 
the masses of the residues. 
 
F.3  CALCULATION 
 
Water insoluble matter retained on any particular sieve, % (m/m) of the total water insoluble  
 
matter = CBA
10000 
 
Where  
A = mass of the insoluble matter on the sieve, g 
B = mass of the test sample used, g C = water insoluble matter present in the test sample, % (from Annex D) 
 DKS 1941 – 3: 2017  
© KEBS 2017 — All rights reserved  6 
Annex G 
Abrasive number of dishwashing bar 
 
G.1 Apparatus 
 
Abrasion apparatus .  An apparatus consisting of the following: 
 a) Container, A  smooth-bottomed cylindrical brass container of internal diameter 63 mm and  
depth 19 mm, and mounted on a base.  The inside of the br ass container is fitted with a clip or ring that 
securely holds the cloth disc (see (d) below) flat on the bottom of the container. 
  
b) Stirrer, A  stirrer mounted directly above the bra ss container, and capable of operating  
smoothly and continuously at 75 ± 5 r/min. 
  
c) Brass disc, A disc, of diameter 50 mm and mass approximately 60 g, made from brass having  
a Rockwell B hardness of 70 ± 1.  The brass disc has one face smoothly buffed, and a screw is so affixed to 
the other face as to enable the brass disc to be connected to the lower end of a vertical shaft of mass such that the combined mass of the shaft and the brass disc is 1800  ± 3 g.  The shaft is so attached to the 
mechanical stirrer that it can be freely lowered to permit the brass disc to rest squarely on the bottom of the 
brass container and raised to permit the withdrawal of the brass disc from the brass container.  
d) Cloth disc,  Discs of diameter 63 mm and cut from billiard table cloth. 
 
G.2 Procedure 
 
G.2.1  Accurately weigh the brass disc and atta ch it to the shaft of the stirrer. 
 
G.2.2 Fit a cloth disc on the inside of the bottom of the brass container. 
 
G.2.3 Mix 5. 0 g of the test sample with 10 ml of water and spread the mixture evenly on the cloth disc.  
Lower the brass disc on to the cloth and rotate the disc through 500 revolutions.  
G.2.4 Raise the stirrer shaft and detach, wash, dry and weigh the brass disc. 
 
G.2.5 Repeat the test twice, using a new cloth disc each time. 
 
G.3 Calculation 
 Calculate the mean loss in mass, in milligrams, of the three determinations and record it as the abrasive number of the dishwashing bar.