KENYA STANDARD  KS 2923 -2:2020  
ICS 55.080  
First  Edition  
  
 © KEBS yyyy  
 Tarpaulins for post -harvest handling of 
agricultural Produce  — Specification     
Part 2: 
Polyester fabric coated with Polyvinyl 
chloride(PVC)   
  
 
 
KS 2923 -2:2020  
ii © KEBS 2020  – All rights reserved  
 TECHNICAL COMMITTEE REPRESENTATION  
The following organizations were represented on the Technical Committee:  
Technical University of Kenya.  
Government Chemist Department  
Kenya  Agriculture and Livestock Research Organization (KALRO)  
Africa PVC Industries  
Nairobi University Department of Food Science  
Environment Institute of Kenya,  
Moi University Department of Industrial and Textile Engineering  
Tarpo Industries Ltd.,  
Agroz Ltd Arusha  
BUMA Holdings  
One Acre Fund  
Kenyatta University  
A Plus Industries Ltd  
Ministry of Agriculture  
National Cereals and Produce Board (NCPB)  
Redblum Industries Ltd  
Government Chemist  
National Public Health Laboratory  
Moi University — Department of ind ustrial and Textile Engineering  
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, 2020  
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 Standards 
may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing f rom th e 
Managing Director.   KENYA STANDARD  KS 2923 -2:2020  
ICS 55.080  
First  Edition  
 
© KEBS 2020  – All rights reserved  iii 
  Tarpaulins for post -harvest handling of 
agricultural Produce    
Part 2: 
 Polyester fabric coated with Polyvinyl chloride(PVC)  
 
 
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  
 @KEBS_ke  
 Kenya  bureau of standards (kebs)  
  
KS 2923 -2:2020  
iv © KEBS 2020  – All rights reserved  
 Foreword  
This Kenya Standard was prepared by the TC 001 cereals and pulses, TC 66 Hard fibres and TC 053 Packaging  
Technical Committee under the guidance of the Standards Projects Committee, and it is in accordance with the 
procedures of the Kenya Bureau of Standard  
KS 2923  consists of the following parts,  under the general title; Tarpaulins for post -harvest handling of 
agricultural Produce    
 Part 1 : Woven High density woven polyethylene  
 Part 2:  Polyester fabric coated with Polyvinyl    chloride (PVC  
During the preparation of this standard, reference was ma de to the following document:  
KS 1434 Specification for Coated Tarpaulin Fabrics  
 
Acknowledgement is hereby made for the assi stance derived from this source   
 KS 2923 -2: 2020  
© KEBS 2020  – All rights reserved  v 
  Introduction  
A tarpaulin  used for post -harvest handling of agricultural produce such as grains  is a large sheet of  flexible, 
water -resistant or  waterproof  material, often  cloth  such as  polyester  coated with  polyurethane ,  of plastics  such 
as polyethylene  and polyvinyl chloride (pvc)  
Development of this standard was necessitated by the ne ed to protect farmers and users of tarpaulins mainly 
used as drying sheets for post -harvest handling of grains from substandard products and safety aspect in terms 
of heavy metal contamination used as printing inks and microbial contamination as a result o f production and 
product handling. In most cases harvested agricultural produce have   high moisture content for safe storage, 
that may result in migration of pigments, organic pollutants from tarpaulins during drying  
Tarpaulins are sold to food value cha ins in Kenya with users benefiting from lower post -harvest losses, maintain 
qualities of stored commodities and leading to Increased food security, income, nutrition and health.  
As the market for tarpaulins expands, there is a risk of substandard products being imported or manufactured 
locally and hence undermine proper storage of dry food commodities and their derived product.  
 KS 2923 -2: 2020    
 
© KEBS 2020 – All rights reserved   
 Tarpaulins for post -harvest handling of agricultural produce  
Part 2: 
Polyester fabri c coated with Polyvinyl chloride  (PVC)  
 
1 Scope  
 
This part two of the Kenya Standard prescribes the requirements, test methods and sampling for polyester fabric 
coated with polyvinyl chloride (PVC) tarpaulins used for post -harvest handling of agricultural produce.  
 
2 Normative references  
 
The following referenced documents 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 (including any amendments) applies . 
 
ISO 13934 -1:2013 Textiles -- Tensile properties of fabrics -- Part 1: Determination of maximum force 
and  
elongation at maximum force using the strip method  
 
KS ISO 105 B02 , Textiles — Tests for colour fastness — Part B02: Colour fastness to artificial light: 
Xenon arc fading lamp test  
 
KS ISO 105 C10 Textiles — Tests for colour fastness — Part C10: Colour fastness to washing with 
soap or soap and soda  
 
KS ISO 105  X12 Textiles — Tests for colour fastness — Part X12: Colour fastness to rubbing  
 
KS ISO 811 Textile fabrics -Determination of resistance to water penetration -Hydrostatic pressure 
test. 
KS ISO 2286 -1 Rubber - or plastics -coated fabrics - Determination of roll characteristics -Part 1: 
Methods for determination of length, width and net mass  
 KS ISO 1421:2016 Rubber - or plastics -coated fabrics - Determination of tensile strength and 
elongation at break   
KS ISO 4674 -1:2016 Rubber -or plastics -coated Fabrics -Determination of tear Resistance -Part 1: 
Constant rate of tear methods.  
KS ISO 22958: 2005 Textiles - Water resistance - Rain tests: exposure to a horizontal water spray.   
 
 
3 Terms and definition  
For the purposes of this standard the following terms and definitions shall apply  
 
3.1  
© KEBS 2020  – All rights reserved  iii 
  grain  
Small hard dry seed with or without an attached hull or fruit layer  harvested for human or animal 
consumption  
 
3.2 
food grade material  
packaging material, made of substances which are safe and suitable for the intended use and which 
will not impart any toxic substances or undesirable odour or flavor to the products.  
3.3 
Base fabric  
This is the inner material between the coatings.  
 
3.4  
Agricultural Produce  
Any product or commodity form cultivated plants or animals intended for human consumption  
 
4 Requirements  
 
4.1 General requirements   
 
4.1.1  The base fabric shall be made from woven or knitted polyester  
 
4.1.2  The base fabric shall be coated on both sides  
 
4.1.3 Edge sealing   
 
All raw edges of the tarpaulins shall be heat sealed or hemmed to prevent fraying  
 
4.1.4 Finish   
On visual examination, the coating of the material shall be uniformly applied and shall be free from cracks and 
flaws.  
 
4.1.5 UV treatments  
The tarpaulins shall be treated with UV stabilizers  
 
5. Specific requirements   
 
5.1 The Tarpaulins shall meet the physical requirements as specified in Table 1  
5.2 The colorfastness requirements of tarpaulins shall be as specified in Table 2 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
iv © KEBS 2020  – All rights reserved  
 Table 1 — Specific requirements for knitted or polyester coated with PVC Tarpaulins  
Characteristic  Requirements  
 Test method  
  Total mass per unit  area,   g/m2, min.  300 KS ISO 2286 -1 
 Coating mass per unit  area,  g/m2, min  200 KS ISO 2286 -1 
 Loss of volatile matter, %,       max  
5 KS 1077 -7 
Retention of breaking 
strength after UV 
exposure ,min  Warp  
85 percent of original 
actual value of the 
tarpaulin  
 ANNEX A  Weft 
 Resistance to water  penetration 
(hydrostatic test)  cm head of water, min.  150 KS ISO 811  
Water resistance, Rain test, g max  
 1 KS ISO 22958  
Breaking strength, N, 
min. Warp  600 
KS ISO 1421  
Weft 500 
 Tear strength, N, min.  Warp  150 KS ISO 4674 -1a 
Trouser shape  
Annex B  
 
 Weft 150 
 
a. if any threads slip out of the fabric the test specimens shall be prepared in accordance with 
annex B of KS ISO 4674 -1 and hemmed at the outside edges  
 
 
 
 
Table 2 — colorfastness requirements for knitted or polyester coated with PVC Tarpaulins  
 
 
 
 
 
 
 
 
 
 
  
Agency  Numerical rating (min)   
Test method  Change in colour  Staining  
Light  5 — KS ISO 105 B02 
 
Washing  4 4 KS ISO 105 -C10  
Rubbing  
 dry 4 
 4  
KS ISO 105 -X12 
wet 3-4 3-4 
  
© KEBS 2020  – All rights reserved  v 
  5.3 Dimensions  
When tested in accordance to KS ISO 2286 -1 the nominal dimensions of the  tarpaulins used in post -harvest 
handling of agricultural produce shall be as declared subject to a tolerance of ± 2 % of the declared dimensions  
 
 
5.4 Food grade requirements  
 
5.4.1 Overall migration  
When tested in accordance with the method specified in FDEAS 985 -1, woven high density polyethylene 
Tarpaulins shall comply with the overall migration limits of 60 mg/kg (max.)  
 
5.4.2  Pigments, colorants and heavy metals  
When tested in accordance with FDE AS 985 -1, woven high density polyethylene Tarpaulins shall comply with 
the list and limits of the pigments, colorants and heavy metals specified therein.  
 
6 Packaging  
 
6.1. woven high density polyethylene Tarpaulins shall  be packed in materials that prevents it from damage, 
contamination during handling, storage and transportation.  
 
7 Labelling  
 
The woven high density polyethylene tarpaulin shall be legibly and indelibly marked with the following 
information  
 
i. Manufacturer’s name, address and /or registered trade mark.  
 
ii. Dimensions of woven high density polyethylene tarpaulin.  
 
iii. Batch number  
 
iv. Instruction for correct use  
 
v. Instruction for storage  
 
i. country of manufacture  
 
7 SAMPLING  
Sampling shall be done in accordance with ISO 24153.  
7.1 Lot  
 7.1.1  The quantity of the same type and quality delivered to one buyer against one dispatch note shall constitute 
a lot.  
7.1.2  The conformity of the lot to the requirements of this Standard shall be determined on the basis of tests 
carried out on the samples selected from the lot.  
7.1.3  The number of pieces to be selected at random from a lot shall be in accordance with Table 3.   
vi © KEBS 2020  – All rights reserved  
 Table 3  Sampling size and permissible number of non -conforming pieces  
 
Number of pieces   
in the lot  Sample size for visual 
inspection  Permissible no. 
Nonconforming pieces   Sub-sample size for  
testing  
  
Up   to 25  
26   to 50  
51   to 150  
151 to 300  
301 to 500  
501 to 1000  
1000 and above    
3  
5  
8  
13  
20  
32  
50    
0  
0  
0  
1  
1  
2  
3   
2  
2  
3  
3  
5  
5  
8  
 
 
  
© KEBS 2020  – All rights reserved  vii 
  Annex  A 
(normative)  
 
UV resistance test  
 
A.1TEST SPECIMENS  
The test specimens for breaking strength shall be cut from the sample as specified in KS ISO 13934 
(Part 1).  
 
A.2TEST CONDITIONS  
 
A.2.1 The test shall be carried out with  Fluorescent -B lamp (313 nanometer or its equivalent).  
 
A.2.2 The duration of the test shall be 144 h (that is 6 days).  
 
A.2.3 The test cycle shall be 8 h at 60 ± 3°C with UV radiation alternating after 4 h at 50 ± 3°C with 
condensation.  
 
A.2.4 Irradiation  level throughout the test shall be maintained at 0.63 +0.03 W/m².  
 
A.3 TEST PROCEDURE  
A3.1 Determine the original average breaking strength of fabric specimens separately as per the 
test Specified in KS ISO 13934 (Part 1).  
 
A3.2 Expose the specimens alternately to ultraviolet light alone and to condensation in one 
respective cycle.  
 
A3.2.1 The type of fluorescent UV lamp, the timing of the UV exposure and the temperature of 
condensation shall be as specified in A -2 
 
A3.3 Determine the average breaking strength of the specimens separately after UV exposure as 
per KS ISO 13934  
A3.4 Determine the percent retention of original strength as follows:  
 
Percent retention of original breaking strength =𝒃
𝒂𝑿 𝟏𝟎𝟎 
 
Where  
 
a = average breaking strength before UV exposure as obtained in A -3.1; and  
 
b = average breaking strength after UV exposure as obtained in A -3.3. 
 
 
NOTES  
1 The UV source is an array of fluorescent lamps (with lamp emission concentrated in the UV range).  
2 Condensation is produced by exposing the test surface to a heated, saturated mixture of air and water vapour, while the  
reverse side of the test specimen is exposed to the cooling influence of ambient room air.