DRAFT UGANDA STANDARD  
  DUS 624  
Second Edition  
2020 -mm-dd 
 
 
 Reference number  
DUS 624 : 2020  
© UNBS 2020   
  
Chrome -tanned bend outer sole leather — Specification  
 DUS 624: 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 fo r its correct application  
© 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 wri tten 
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 7 333 2 50/1/2 
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  
 DUS 624 :2020  
© UNBS 2020  – All rights reserved  iii 
 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 U ganda , 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 Nationa l 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 consist s of key stakeholders 
including government, academia, consumer groups, private sector and other interested parties.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the 
general public for comments. The co mmittee 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, leather, paper 
and related products , Subcommittee SC 2, Leather and related products . 
This second edition cancels and replaces the first edition ( US 624:2006 ), which has been tec hnically revised.  
 DRAFT UGANDA STANDARD  DUS 624 : 2020  
 
© UNBS 2020  – All rights reserved  1 
 Chrome -tanned bend outer sole leather — Specification  
1 Scope   
This draft Uganda standard specifies  requirements , sampling and test methods  for chr ome tanned, wax 
impregnated bend outer sole leather . 
2 Normative references   
The following referenced documents referred to in the text in such a way that some or all of their conten t 
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 2588, Leather — Sampling — Number of items for a gross sample  
US ISO 2419, Leather — Physical and mechanical tests — Sample preparation and conditioning  
US ISO 2589, Leather — Physical and mechanical tests — Determination of thickness  
US ISO 3378, Leather — Physical and mechanical tests — Determination  of resistance to grain cracking and 
grain crack index  
US ISO 3380, Leather — Physical and mechanical tests — Determination of shrinkage temperature up to 100 
°C 
US ISO 4045, Leather — Chemical tests — Determination of pH and difference figure  
US ISO 4047,  Leather — Determination of sulphated total ash and sulphated water -insoluble ash  
US ISO 4098, Leather — Chemical tests — Determination of water -soluble matter, water -soluble inorganic 
matter and water -soluble organic matter  
US ISO 5398 -1, Leather — Chemic al determination of chromic oxide content — Part 1: Quantification by 
titration  
3 Terms and definitions   
For the purposes of this document, the followi ng terms and definitions apply.  
ISO and IEC maintain terminological databases for use in standardization at the following addresses:  
— ISO Online browsing platform: available at http://www.iso.org/obp  
3.1  
bend  
half a bovine hide, produced by cutting along the backbone line with the belly and shoulder parts removed   
2 © UNBS 2020  – All rights reserved  
 4 Requirements  
4.1 Physical  requirements  
4.1.1 General  
The leather shall be:  
a) chrome -tanned bends of good  quality;  
b) shall not be fleshy, and shall be free from excessive grain damag e and from widespread flay cuts;   
c) any defects present shall be such that the cutting area of a bend is not reduced by mo re than 6.5 dm²; 
and  
d) the leather shall be wax impregnated. Surplus wax shall be removed.  
4.1.2  Thickness  
The nominal thickness (substance) of the leather shall be in one of the following range s as specified by the 
purchaser  
a) 3.7 mm – 4.8 mm;  
b) 4.8 mm – 5.8 mm; or 
c) 5.8 mm – 7.4 mm. 
The actual  thickness  at any point  on a bend  shall not fall outside  the appropriate  range  by more  than 0.5 mm. 
4.1.3  Shrinkage temperature  
The shrinkage  temperature,  determined  in accordance  with 5.2, shall be not more  than 100°C. 
4.1.4  Resistance to grain cracking  
When tested in accordance with 5.3, the leather shall not crack when bent, grain side out, through 180° over a 
mandrel of diameter 61.67 mm.  
4.2 Chemical requirements  
4.2.1  pH value  
The pH value of leather, determined in accordan ce with 5.4, shall be at least  minimum  3.3 
4.2.2  Total ash content  
The total ash content of the leather, determined in accordance with 5.5, shall not exceed a mass fraction of 17  
% on a 14 % moisture basis.  
4.2.3  Water soluble matter  
The water -soluble matt er content of the leather, determined in accordance with 5.6, shall not exceed a mass 
fraction of 8 % on a 14 % moisture basis . DUS 624 : 2020  
© UNBS 2020  – All rights reserved  3 
 4.2.4  Chromic oxide content  
The chromic oxide content of the leather, determined in accordance with 5.7 and calculated on a mois ture-free 
and grease -free basis, shall be at least a mass fraction of 3.5 %  
5 Methods of test 
5.1 Conditioning  of test samples  
Use the procedure  given  in US ISO 2419 . 
5.2 Shrinkage  temperature  
Use US ISO 3380  
5.3 Resistance  to grain  cracking  
Use US ISO 337 8 
5.4 pH value  
Use US ISO 4045  
5.5 Total  ash content  
Use US ISO 4047  
5.6 Water  soluble  matter  
Use US ISO 4098  
5.7 Chromic  oxide  content  
Use US ISO 5398 -1 
5.8 Thickness  
Use US ISO 2589  
6 Packaging  
The sole leather  shall be wrapped in a suitable material tha t will prot ect them  from damage during normal 
transportation and storage . 
7 Labelling  
The following shall be legibly and indelibly labelled on the package : 
a) manufacturer’s name, address and/or trade mark  
b) country of origin   
4 © UNBS 2020  – All rights reserved  
 c) thickness  
d) weight  
e) dimensions  
f) descrip tion of the product  e.g chrome tanned be nd outer sole leather  
8 Sampling  
Sampling shall be done in accordance with ISO 2588  DUS 624 : 2020  
© UNBS 2020  – All rights reserved  5 
 Bibliography  
[1] US 624 :2006,  Vegetable -tanned bend outer sole leather — Specificatio n 
 DUS 624 : 2020  
© UNBS 2020  – All rights reserved  7 
 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 th at 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 licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 DUS 624 : 2020    
 
ICS 59.140.35 
Price based on nn pages  
© UNBS 2020 – All rights reserved