TDC 3( 6198) P 3 
                                                                                                   First Edition  
 
 
 
 
 
 
 
Textiles – High Density Polyethylene (HDPE)/ Polypropylene (PP) 
Woven Sacks for Packaging of 50kg/25kg sugar  – Specifications.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
i 
 Foreword  
 
This First Edition of this D raft Tanzania Standard has been prepared to specify requirements to be complied 
with   manufacturers producing High Density Polyethylene (HDPE)/Polypropylene (PP)  Woven Sacks for 
Packing of 50 kg/25kg of sugar . 
 
This Draft Tanzania Standard describes the construction of the sacks, their dimensions and test methods 
suitable for ensuring long term  storage and transportation of sugar . 
 
In preparation of This Draft Tanzania Standard assistance  was derived from:  
IS 14 968: 2014 Textiles – High Density Polyethylene (HDPE)/ Polypropylene (PP) Wo ven 
Sacks for Packaging of 50kg/25kg Sugar – Specification . 
ISO 23560: 2015 Woven Polypropylene Sacks for bulk packaging of foodstuffs.  
 
 
 
  
1 
 1 Scope  
This Draft Tanzania Standard prescribes the requirements of two types of HDPE /PP woven sacks suitable 
for packaging of sugar.  
Type 1 – Sacks having packaging capacity of 50kg  
Type 2 – Sacks having packaging capacity of 25kg.  
2   Normative references  
The following referenced documents are indispensable for the application of this Draft Tanzania  Standard.  
For dated references, only the edition cited applies. For undated references, the latest edition of the 
referenced document (including any amendment) applies.  
i) TZS 4, rounding off numerical values  
ii) TZS 20, Textiles – Woven fabrics – Determination of number of threads per unit length and per 
unit width.  
iii) TZS 21, Textiles – Woven or knitted fabrics – Determination of  mass per unit length and per 
unit area.  
iv) TZS 22, Textiles - Woven fabrics - Determination of breaking load and extension  
v) TZS 44, Textiles – Woven o r knitted fabrics - determination of width and length.  
vi) TZS 834: 2005,  Textiles – Determination of commercial mass consignments of textiles fibres 
and yarns . 
vii) ISO 13953, Polyethylene (PE) pipes and fittings -- Determination of the tensile strength and 
failur e mode of test pieces from a butt -fused joint.  
viii) ISO 3451 -1, Plastics -- Determination of ash -- Part 1: General methods.  
3 Terms and definitions  
For the purposes of this Draft Tanzania Standard , the following terms and definitions shall apply.  
3.1 HDPE /PP Sacks  
Container made of woven HDPE /PP fabric closed at one en d. 
3.2 Liner bag ,  
An inner bag which is fitted a sack to  provide additional protective properties against air, water vapour 
migration and effect of light.  
3.3 Laminated sacks  
Sacks made of super imposed  layers of paper, wood or fabric bonded or impregnated with resin and 
compressed under heat.  
3.4 Ends  
Yarns running along the length of and parallel to the sacking selvedge.   
2 
 3.5 Picks  
Yarns running across the width of the fabric and “perpendicular” to the sacking selvedge.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         
3.6 Sacking  
A coarse fabric  used  for making sacks or bags . 
3.7 Bale  
 
A rectangular pressed rigid package containing woven bags covered  with protective wrappings that are 
stitched and/or securely bound.  
3.8 Contract – mass (bale)  
 
The mass as obtained by multiplying the nominal mass of a bag by specified number of bags in that bale.  
3.9 Lot 
 
All bale s containing similar woven bags.  
4   Manufacture  
4.1 Raw material  
The HDPE or PP used for manufacture of tape shall be of the acceptable quality. The  raw material 
composition to be used for manufacturing of the HDPE/PP woven sacks shall be as agreed to between 
buyer and seller.  
4.2 Fabric  
The fabric used in the manufacturing  of HDPE /PP woven bags shall be woven on a circular loom  from 
HDPE/PP tapes having 2.5  mm (tolerance of ± 10%) and linear density of 111 tex (1000 denier)  (the 
dimension /linear density of the tape can also be agreed between buyer and seller) .  
The denier of HDPE/PP tape used in the manufacture of woven fabric/sacks shall be subjected to the 
following tolerances:  
a) ± 10% on individual value, and  
b) ± 5 Percent on average.  
The construction particulars of  the fabric shall be as given in Table 1.  
4.3 Sacks  
The sacks shall be produced from tubular fabric woven on a circular loom and cut to the required length.  
4.3.1 Bottom Seam  
The stitching of bottom seam shall be done with single/double  rows of chain stitch. The two rows of stitches 
shall be sepa rated from each other by minimum 5mm and the outer stitch shall be minimum 8mm from the 
outer edge of the sacks. The stitching shall be done with double fold over seam to a depth of minimum 
25mm, so that the stitches pass through a minimum of four layers  of the fabric. The number of stitches/dm 
shall be 14 ± 2.   
3 
 The yarn used for stitching shall be UV stabilized HDPE/PP  yarns or any other UV thread suitable for the 
purpose. The stitching shall be uniform without any loose thread or knot s. 
4.3.2 Mouth of the Sack  
The completely open mouth of the sack shall be hemmed with a fold of minimum 5mm and tapes shall not 
fray. 
4.4 Liner  
If required by the buyer the unlaminated sacks shall be provided with a loose liner of food grade virgin 
LDPE/LLDPE/HMHDPE/PP of an ac ceptable quality.  The liner shall be free from pin holes (except for air 
removal holes), patches, tear, blisters and any other visible defects.  
4.5 Capacity  
The sack shall have the nominal capacity of 25kg and 50kg.  
Note: The capacity of the sack can also base on an agreeme nt between the buyer and seller.  
5 Requirements  
5.1 Mass of bale  
The mass of bale of sacks (excluding packing  materials) shall be with in ± 3% of the mass calculated by 
multiplying the number of sacks with  the mass of sack specified in T able 1.  
5.2 The sacks shall conform to  the requirements specified in T able 1.  
Table 1 – Requirement of the sacks.  
SN characteristics  Requirements  
 
 Tolerance  Test 
Methods  Type 1  Type 2  
50kg  25kg  
1 Average Breaking strength of 
fabric, N, min (ravelled strip 
method, (200mm x 50mm ) 
a) Width wise  
b) Length wise   
 
 
500 
500  
 
 
500 
500  
 
- 
-  
 
 
ISO 13934: 1  
2 Minimum brea king strength of 
bottom seam (ra velled strip 
method), Min, N (kgf)   
250  
250  
-  
IS 9030  
3 Average  Breaking  strength and 
elongatio n at break of UV 
stabilized HDPE /PP fabric after 
been exposed to UV radiation 
and weathering, min (kgf).   
Not less than 50%  
of original 
strength   
Not less than 
50%  of original 
strength   
-  
Annex A 
4 Dimensions( mm), min  
i) Length   
900  
630  
-  
TZS 44  
4 
 Note 1: Requirement number 8 and number 3 are subjected  to the agreement between manufacturer and buyer.  
 
Table 2 – Requirements of the liner  
6 Printing Marking and Pa ckaging . 
6.1 Printing on Sacks  
 
The sacks shall be printed with food grade printing inks with identification mark of sack manufacture along 
with the information as required by the buyer.  
6.2 Marking on bales  
The bales shall be marked with the following information:  
a) The name of the manufacturer;  
b) The type and size of sack;  
c) The gross mass of the bale;  
d) The net mass of the bale;  ii) width  540 480 
5 Elongation at break of fabric (%)  
i) Lengthwise, (min)  
ii) Width wise, (min)   
20 
20  
20 
20  
-  
IS 1969(Part 
1) 
6 Mass per unit area of the fabric 
(g/m2), min  65 65  TZS 21  
7 Number of yarns per Decimetre  
i) Ends/dm  
ii) Picks/dm   
40 
40  
40 
40  
± 2%  
± 2%   
TZS 20  
 
8 Ash content (for UV stabilized 
fabrics), Max, Percent   
2.2  
2.2 - ISO 3451 - 1: 
2008, 
Method A.  
SN characteristics  Requirements  
 
 Tolerance  Test 
Methods  
1. Weight of the liner (mic ron), 
min 
 30 - TZS 21  
2. Dimension of liner  
c) Width of loose liner  
d) Length wise  At least 20mm more than the specified 
width of the sack.  
At least 50 mm more than the specified  
length of the sack.   
 
- 
-  
IS 1969(Part 1)  
3 Bottom seam of loose liner  At least 25mm from the bottom edge  - IS 9030   
5 
 e) Date  of manufacture;  
f) Any other in formation required by the buyer;  
g) Identification Mark;  
h) Number of sack.  
Note - Each sack shall be compulsorily marked with visible recycling logo as given below at a space on bottom of 
the bag compactible with the  art work of the buyer for printing the sack and the bale.  
 
6.3 Packaging  
The sacks shall be packed to form a bale using a layer of HDPE/PP woven fabric and suitably secured. 
The bale shall contain 500 sacks or multiple thereof.  
7 Sampling  and Criteria for Conformity.  
7.1 In a consignment, all the sacks of the same construction shall be grouped together to constitute a lot.  
7.2 The conformity of the lot to the requirements of this Draft Tanzania Standard shall be determined on 
the basis of the tests carried out on the samples selected from it.  
7.3 The number of samples to be selected depends on the size of the lot and the number of bales to be 
sampled  shall be in accordance with column  2 and column  3 of Table 3.  
The number of sacks to be selected from the bales sampled shall be in accordance with column 3  of Table 
3 for visual inspection, dimensions, ends, picks and mass requirements and shall be in accordance with 
column 4 of T able 3  for breaking strength of bott om seam and percent elongation at break requirements.   
The samples should be selected in accordance with column 5 of T able 3  for determination of ash content 
and also breaking of fabric after UV radiation exposure.  
7.4 Number of Tests – The number of sack s to be selected for testing dimensions and mass of sacks shall 
be according to column 3 of Table 3.  
7.4.1 The number of sacks to be selected for testing breaking strength and seam breaking strength shall 
be two per bale selected according to column 2 of T able 3 subject to a maximum of 10 bags.  
 
 
6 
 Table 3:  Sample size  
 
7.5 Criteria for conformity  
The lot shall be considered as conforming to the requirements of the standard, if the following conditions 
are satisfied:  
a) The number of defective sacks in case  of visual inspections, ends, picks and dimensions is up to 
10% of the sample size subject to rounding off the fraction to next higher integer.  
 
b) None  of the sack or bale of 500 sacks weighs after allowing tolerance of ±6 % on individual sack 
and ±3 % on a ba le of 500 sacks, higher weight can be accepted.  
 
c) The average breaking strength of fabric in both lengthwise and width wise is not less than the value 
specified and none of the individual bag value is more than 10 % below the specified value. The 
samples sel ected for breaking strength tests shall be free from defects in visual inspection, 
dimensions, ends, picks and mass requirements.  
 
d) The average breaking strength of fabric at bottom seam is not less than the value specified and 
none of the individual bag va lue is more than 10 % below the specified value. The samples selected 
for bottom seam breaking strength tests shall be free from defects in visual inspection, dimensions, 
ends, picks and mass requirements and test carried on the centre portion.  
 
e) None of the  HDPE/PP sack samples after exposing to UV – radiation and weathering shall have a 
breaking strength less than 50 % of the original value.  
f) None of the sample sacks shall have percentage elongation and ash content outside the specified 
range.  
ANNEX  A No. of HDPE/PP 
sacks in a lot  Number of 
Bales to be 
sampled  Sample size for 
visual Inspection, 
Dimensions, 
Ends, Picks and 
Mass 
Requirements  Sample size for Breaking 
Strength of HDPE/PP 
Fabric before Exposing to 
UV Radiation, Breaking 
Strength of seam and 
Elongation at Breaking 
Requirements.  Sample Size for 
Breaking Strength  of 
HDPE/PP Fabric after 
Exposing to UV 
Radiation 
Requirement and Ash 
Content.  
Up to 25, 000  3 12 8 1 
25,001 to 50,000  5 20 10 2 
50,001 to 100,000  8 32 13 3 
100,001 and above  12 48 18 4  
7 
 (Normative)  
UV RESISTANCE TEST  
A – 1 To determine the effect of UV radiation and weathering on the breaking strength, the HDPE/PP 
Woven fabrics shall be  exposed as given in A - 2 and A  – 3. 
A – 2 TEST PROCEDURE  
The test shall be carried out with fluorescent  UV – Lamp type B (313nm or its equivalent).  
The duration of the test shall be 192h (that is eight days) in continuous mode.  
The test cycle shall be: 8h at 60 ℃ ± 3℃ with UV – radiation alternating with 4h at 50 ℃ ±3℃ condensation. 
Irradiance level throughout the test shall be maintained at 0.63 (+0.04/ -0) W/m2. 
A – 3 TEST PROCEDURE  
A – 3.1 Determine the original average breaking strength of fabric as per test method specified in IS 1969 
(part 1)  
A – 3.2 Expose the specimens alternately to ultravio let light and condensation in respective test cycle in 
continuous mode for total 192h.  
The type of fluorescent UV lamp, the timing of the UV and condensation exposure and the temperature  of 
the UV exposure and cond ensation shall be specified in A -2. 
A – 3.3 Determine the average breaking strength of the fabric separately after UV exposure as mentioned 
above.  
A – 3.4 Determine the p ercent retention of original strength as follows:  
Percentage retention of original breaking strength = 𝑎
𝑏  𝑥 100 
Where  
a) a= av erage breaking strength bef ore UV exposure as obtained in A  – 3.1 
b) b= average breaking strength af ter 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.