KENYA STANDARD   DKS 675:2024 
ICS 59.140 
Third   Edition  
 
 © KEBS 2024  
 Leather—Chromed crust bovine leather — 
Specification  
 
 
 
 
 
 
 
PUBLIC REVIEW DRAFT  MARCH  2024DKS 03-391:2024   
 
© KEBS 2023 – All rights reserved   
 TECHNICAL COMMITTEE REPRESENTATION  
The following organizations were represented on the Technical Committee:  
Kenya Industrial Research and Development Institute (KIRDI)  
Kenya Association of Manufacturers (KAM)  
Bata Shoes Company  
Dedan Kimathi University of Technology(DeKUT)  
Technical University of Kenya (TUK)  
Environmental Institute of Kenya (EIK)  
Kenya Leather Development Council (KLDC)  
Department of Veterinary Services (DVS)  
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  2024 
Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 130 of 2001 of  the Laws of Kenya, copyright subsists 
in all Kenya Standards and except as provided under Section 25 of this Act, no Kenya Standard produced by Kenya Bureau of Sta ndards 
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Managing Director.  
   
Leather—Chromed crust bovine leather — 
Specification  
 
 
  Kenya Bureau of Standards, Popo Road, Off Mombasa Road,  
P.O. Box 54974 - 00200,  Nairobi, Kenya  
 +254 020 6948000, + 254 722202137, + 254 734600471  
 info@kebs.org  
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 kenya bureau of standards (kebs)  
 
Foreword  
This Kenya Standard has been prepared by the Technical Committee on Leather and Leather Products under 
the guidance of the Standards Projects Committee, and it is in accordance with the procedures of the Kenya 
Bureau of Standards.  
 
In the revision of this standard, new test methods have been included.  
 
This standard cancel and replaces KS 675: 2017, Specification for chromed crust bovine leather.  
 
During the preparation of this standard, reference was made to the following documents:  
 
ISO 5431:2013, Leather — Wet blue goat skins — Specification.  
 
ISO 5432:2013, Leather — Wet blue sheep skins — Specification.  
 
Acknowledgement is hereby made for the assistance derived from these sources.  
Leather—Chromed crust bovine leather — Specification  
1 Scope  
This Kenya Standard specifies the requirements, test methods and sampling for chromed  leather  from bovine 
and goat/sheep . This standard is not applicable to leather made from other tanning methods other than chrome 
tanning.  
 
 
2 Normative Reference s 
The following 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 (in cluding any amendments) applies.  
 
KS 819, Glossary of terms relating to hides, skins and leather  
 
ISO 2418 , Leather—Chemical, physical, mechanical and fastness tests — 
Position and preparation of specimens for testing  
 
KS ISO 2588, Leather — Sampling — Number of items for a gross sample  
 
KS ISO 3376,  Leather — Determination of tensile strength and elongation  
 
KS ISO 3380,  Leather — Shrinkage temperature  
 
KS ISO 4045,  Leather — Determination of pH      
 
KS ISO 4047,  Leather — Determination of sulphated total ash and sulphated water -insoluble ash  
 
KS ISO 4048,  Leather — Chemical tests — Determination of matter soluble in dichloromethane and free acid 
content  
 
KS ISO 4684, Leather — Chemical tests — Determination of volatile matter  
  
KS ISO 4098,  Leather — Chemical tests — Determination of water -soluble matter, water -soluble inorganic 
matter and water -soluble organic matter  
 
KS ISO 3377 -2, Leather — Physical and mechanical tests — Determination of tear load — Part 2: Double edge 
tear 
 
KS ISO 5398 -3, Leather — Chemical determination of chromic oxide content — Part 3: Quantification by atomic 
absorption spectrometry  
 
3 Terms and definitions  
For purposes of this document, the terms and definitions given in KS 819 and the following  shall apply.  
 
3.1  
chromed skin /hide  
skin/hide  tanned by chromium salts.  
 
3.2  
chromed crust leather  
skin/hide that has been tanned with chromium salts, split and shaved as  its required, subsequently re -tanned, 
fat liquored, conditioned, staked, if necessary dyed, trimmed, measured and dried  
 
3.3  
semi -finished state  
products not fully finished but can be traded with  
 
4 Requirements   
4.1 General requirements  
Raw materials  
 
The raw material shall be fresh or preserved  goat/sheep skin or bovine hides  by methods other than tanning.  
 
4.1.1 Tanning  
 
The material after being treated by usual pre -tanning operations namely soaking, liming, degreasing and 
pickling, shall be tanned using chrome salts. To inhibit mould growth, suitable fungicides shall be incorporated 
in the skin.  
 
4.1.2  Visual examination  
 
The tanned crust leather shall be smooth on the grain side, free from hair and chrome stains. The flesh side 
shall be well fleshed.  
 
4.2 Specific requirements  
4.2.1 Physical and chemical requirements  
 
Chromed crust leather shall comply with the requirements given in Table 1.  
 
 
  
 
 
 
Table 1 — Physical and chemical requirements of chromed crust bovine  leather  
  
 
SL. No.  
N  
Characteristic   
Requirement  
 
Test method  
Bovine  Goat 
/sheep  
(i) 
  
Chrome content (as Cr 2O3) % 
by weight on dry leather, min.  
  
               2.5  
KS ISO 5398 -1 
ii) 
 Soluble matter in 
dichloromethane and free fatty 
acids  2.0 KS ISO 4048  
(iii) pH of the water extract, min.                  3.5 KS ISO 4045  
(iv) Shrinkage temperature in ºC 
min.                 100 ºC KS ISO 3380  
v) 
 Sulphated ash and water 
insoluble ash  4 KS ISO 4047  
(vi) Tensile strength (after drying 
and conditioning)  Mpa, min.  15 10 KS ISO 3376  
(vii) Moisture content, % m/m  10-12 KS(ISO 4684  
(viii) Water soluble organic and 
inorganic substances, %, max.  10  KS ISO 4098  
ix) Tear load, N, min.  70 20 KS ISO 3377 -2 
x Elongation at break,%,min.  45 -75 35 - 75 KS ISO 3376  
 
5 Grading  
 
The crust leathers shall be graded into six selections as given below.  
 
Grades 1, 2 and 3 are packed together in proportion 20:40:40 and can be traded in as run quality or tannery 
run.  
 
5.1  Grade 1  
 
The crust leathers shall have a good grain with well filled flanks and up to two small defects such as healed 
scratches.  
 
The crust leathers shall be completely free from brand marks and flay cuts. 100 % of the area shall be usable.  
 
5.2 Grade 2  
 
The crust leathers shall have a good grain with well filled flanks and up to four defects (healed scratches) and 
not more than 25 % drawn grain.  80 % of the area shall be usable.  
 
5.3  Grade 3  
  
The crust leathers shall have a good grain with up to eight small holes and twenty healed scratches. Drawn 
grain and loose substance should not be more than 50 %. Usable area shall be 70 %.  
 
5.4  Grade 4  
 
The crust leathers may have one brand mark, small holes, healed scratches and flay cuts which are not deep.  
60 % of the area shall be usable.  
 
5.5  Grade 5  
 
The crust leathers may have defects over the grains, deep wrinkles around the neck and two brand marks and 
deep flay cuts.  40 % of the area shall be usable.  
 
5.6 Rejects  
 
Any crust leathers below the standard of Grade 5 are called rejects.  
 
6 Packaging  
 
6.1  Packing  
 
Packing shall be done in such manner that the crust leathers on being unpacked will be free from creases 
or creasing would be minimized during storage.  
 
7 Marking  
 
The package shall be marked or labeled with the following information:  
 
i) Name and address of manufacturer or packer;  
 
ii) Month and year of manufacture (when they were tanned);  
 
iii)  Grade of the crusts leather (if any); and  
 
iv) Number and total area of the pieces.  
 
8    Sampling and criteria for conformity  
 
The sampling and criteria for conformity shall be as prescribed in KS ISO 2588.  The location of test pieces shall 
be as specified in ISO 2418 .