Earthsoul Bag Specifications  
 
  • Scope
  • Normative References
  • Definitions
  • Designation
  • Applications
  • Dimensions & Types
    • Large Size
      • Heavy Duty bags
      • Normal Duty bags
    • Medium Size
    • Small size
  • Requirements
    • Tolerances on length and half perimeter
    • Tolerances on thickness
    • Tolerances on mass
    • Resistance to dropping of bags filled with wet water
    • Load resistance and watertight
    • Tensile properties
      • Tensile strength at break
      • Percent elongation at break
      • Young Modulus
    • Tear Resistance
      • Initial Tear Load
      • Propagation Tear Load
    • Compostability
  • Sampling
  • Test Methods
    • Measurement of useful length & half perimeter
      • Apparatus
      • Useful length
      • Half Perimeter
    • Measurement of thickness
      • Apparatus
      • Procedure
    • Measurement of Mass
    • Resistance to dropping of sacks filled with wet matter
    • Load resistance and watertight
    • Tensile properties
      • Tensile strength at break
      • Percent elongation at break
      • Young Modulus
    • Tear Resistance
      • Initial Tear Load
      • Propagation Tear Load
    • Composting
      • Disintegration Test
      • Controlled Composting test
  • Marking
 
  1. Scope
This standard specifies the general characteristics, type test performance and certification requirements for biodegradable and compostable sacks made with bio-polymeric films, used for the source separated collection of the organic fraction of household waste.

 
   
  2. Normative References
The normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendment to or revision of any of these publications apply to only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies.
UNI 7315: Polyethylene bags for separated collection in cities. (Italy)
ASTM D 1938-8S Standard Test Method for Tear Propagation Resistance of Plastic Film and Thin Sheeting by a Single-Tear Method
ASTM D 882 Standard Test Method for Tensile Properties of Thin Plastic sheeting.
UNI - 8516 Film and Plastic film. Determination of the air mass and thickness by gravimetery (as in ISO 4591-79)
ISO-4593 Plastics - Film Sheeting m- Determination of Thickness by Mechanical Scanning
CEN TC 261/SC4/WG2 Requirements of packaging recoverable in the form of composting and biodegradation - Test scheme for the final acceptance of packaging.
CEN TC 261/SC4/WG2: Evaluation of the ultimate aerobic biodegradability and disintegration of packaging materials under controlled composting conditions - Method by analysis of released carbon dioxide.
 
   
  3. Definitions
Biodegradation is a degradation caused by biological activity especially by enzymatic action leading to a significant change of the chemical structure of a material.
Biowaste, organic fraction of household waste
Compostability, is a property of packaging to be biodegraded in a composting process. To claim Compostability it must have been demonstrated that a packaging can be biodegraded and disintegrated in a composting system (as can be shown by standard test methods) and completes its biodegradation during the end use of the compost. The compost must meet the relevant criteria. Quality criteria are e.g. - heavy metal content; no ecotoxicity; no obvious distinguishable residues.
Gusset. A fold inserted in the longitudinal edge of a tube or a sack. Half perimeter P, the internal width of the sack, measured with gussers opened, if any. Nominal thickness, the thickness of the film as declared by the manufacturer or agreed upon in the contract, in micrometer (um)
Organic Recovery, is the biological treatment of packaging waste in aerobic composting or anaerobic biogasification facilities with following aerobic stabilization with the aim to reduce the waste and obtain compost.
Sack means open mouth sack
Useful Length, the distance from the seal to the mouth of the sack, measured inside the sack lying flat.

 
   
  4. Designation
Biodegradation is a degradation caused by biological activity especially by enzymatic Sacks are designated using the following information:
(a) the denomination Compo-bio sacks
(b) the size, in millimeters
(c) the color,
(d) the nominal thickness, in micrometer;
(e) the reference to this standard
Example of designation:
For a Compostable sack 700mm X 1100mm, green, 40um thick;
Compo-Bio Sacks-700/1100-green-40-EN xxxx

 
   
  5. Applications
Compostable sacks made with bio-polymers are applied in the source separated collection of the organic fraction of the household waste. The final intended treatment system for both the Biowaste and the sack is organic recovery in aerobic composting or anaerobic biogasification.

 
   
  6. Dimensions and Types
The dimensions of the sacks will vary according to the use and function and , in principle they will rely on the agreement between sellers and buyers. However, some classes can be individuated:
6.1 Large size Typical dimensions of these sacks are 700mm x 1100 mm with a volume of 137 dm3.
6.1.2. Heavy duty sacks. Preferred application is for the collection of Biowaste from communities (such as Hotels, refectories, messes, canteens, homes, hospitals, etc.) and from apartment buildings, where many households pour their Biowaste in a central collection unit or for the collection of very pointed and sharp yard trimmings from parks or gardens (class L-1)
6.1.3. Normal duty sacks, preferred application is the collection of yard trimmings from parks or gardens (class L-2)
6.2 Medium size Typical dimensions of these sacks are 700 mm x 700 mm with a volume of 75 dm3. For the collection of Biowaste from apartment buildings and yard trimmings (class M).
6.3 Small Size. Typical dimensions of these sacks are 350 mm x 420 mm with a volume of 12 dm2. For the collection of Biowaste from as single household (class S).

 
   
  7. Requirements
7.1 Tolerances on length and Half Perimeter: Tolerances to the nominal dimensions, measured with the precision of 1 mm, shall be of 2.5% in comparison with the nominal values.
7.2 Tolerances on Thickness: The average thickness shall not diverge more than: 10% of nominal value, for the sacks with a thickness equal or higher than 0.05mm; 15% of nominal value for sacks with a thickness lower than 0.05 mm;
7.3 Tolerances on Mass: A tolerance of ~3% on the total mass is allowed for the whole consignment. This tolerance is determined on the total mass of all batches, not for each single batch. The total mass is considered the nominal mass declared at the offer or in the consignment note.
7.4 Resistance to dropping of sacks filled with wet matter: Level of rupture of sacks shall be less than 10%.
7.5 Load Resistance and Watertight: Sacks shall display neither ruptures nor water and shavings leakage.
7.6 Tensile Properties
7.6.1 Tensile Strength at Break. The average tensile strength at break, expressed in Mpa, shall be equal or higher than that indicated in Table 1. If the deviation from average of a single measurement is higher than 10%, the test shall be repeated using another 5 specimens.
7.6.2 Percent Elongation at Break. The average values, expressed in percentage, shall be equal or higher than those indicated in Table 1. 7.6.3 Young Modulus. The average values shall be equal or higher than those indicated in Table 1.

 
  Table 1 Tensile properties: Acceptability limits

 
  Orientation of specimens as regards the sack

 
 
Parameter direction Longitudinal direction Cross direction
Young modulus (Mpa) >100 >100
Tensile Strength at Break (Mpa) >20 >15
Percent of Elongation at break (%) >600 >500
 
 
7.7 Tear Resistance. The measurement is done according to the Standard ASTM D 1938, with a speed of 250mm/min.
7.7.1 Initial Tear Load. The average values shall be equal or higher than those indicated in Table 2.
7.7.2 Propagation Tear Load. The average values shall be equal or higher than those reported in Table 2.

 
  Table 2 Tear Resistance: Acceptability limits:

 
  Orientation of specimens as regards the sack

 
 
Longitudinal direction
Initial Tear Load >50
Propagation Tear Load >50
Cross direction
Initial Tear Load >55
Propagation Tear Load >55
 
 
7.8 Compostability. The film used for the compostable sacks shall comply with the criteria outlined in the test procedures indicated by the CEN TC 261/SC4/WG2 Requirements for packaging recoverable in the form of composing and biodegradation - Test scheme for the final acceptance of packaging. The CEN procedures are based on several tests and shall be applied to get the qualification of packaging recyclable through composting and the compostability label. For batch testing a disintegration screening test (such as the CEN TC 261/SC4/WG2 draft box test method) can be sufficient to verify Compostability.
However, if a more complete check is needed, also the other test procedures can be applied and in particular a controlled composting test is recommended (CEN TC 261/SC4/WG2: Evaluation of the ultimate aerobic biodegradability and disintegration of packaging materials under controlled composting conditions - Method by analysis of released carbon dioxide). The average disintegration and biodegradation shall not diverge from the threshold pass level (as established by CEN or other authority including ASTM) more than 5%. It is also possible to verify the compliance of a batch using an analytical approach. In this case the material is identified through suitable analytical procedures and compared with a sample of the material originally tested for compostability, retained as reference.

 
   
  8. Sampling
The number of batches for each consignment shall be defined with an agreement between seller and buyer. Usually the term batch is meant to indicate a production having features of uniformity and continuity, that is being run with the same equipment, same raw materials, and in a continuous productive cycle. The minimum number of sacks to be withdrawn from each batch to perform the tests above described is indicated in Table 3, as a function of the batch dimensions. None of the sampled sacks shall display values in excess to the required tolerances. Otherwise, the following procedure shall be adopted. The sampling shall be repeated withdrawing a same number of sacks and repeating the same measurements. In case of a second negative outcome the batch will be considered out of specification. In case of a positive outcome, the sampling shall be repeated withdrawing a same number of sacks and repeating the measurements for the third time. In case of a positive results the batch will be considered within the specifications, otherwise will be considered out of specifications.

 
  Table 3 Number of sacks to be sampled for each test as a function of batch size:

 
 
Number of sacks for each batch Dropping test Load resistance test, measurements Controlled dimensions & mass, tensile properties, composting test & disintegration in composting conditions
below 15,000 10 3 sacks for a least 300g (3 replicates)
15,000-100,000 20 6 sacks for atleast 300g (3 replicates)
100,000-500,000 30 9 sacks for a least 600g (3 replicates)
over 500,000 40 12 sacks for a least 600g (3 replicates)
 
   
  9. Test Methods
9.1 Measurements of Useful Length and Half Perimeter
9.1.2 Apparatus. Ruler or equivalent, having the precision of 1mm.
9.1.3 Useful Length. With the sack lying flat, measure the useful length along the two edges between top (opening) of the sack and the inner side of the seam, at the bottom of the sack
9.1.4 Half Perimeter. Cut the seam and if applicable, unfold the gussets. Measure the half perimeter at mid-length between the top and the bottom of the sack. The half perimeter is expressed in millimeters (mm), rounded to the nearest upper or lower millimeter. In case of sacks with the edge seams, the half perimeter shall be measured between the inner sides of the seams.
9.2 Measurement of thickness
9.2.1 Apparatus. The thickness shall be measured with a micrometer having the precision of 1um, supported with a flat contact surface of 2.5 to 10mm diameter and a probe with flat surface of same dimension, with an applied load from o.1 to 0.5 N. For probes with spherical head, the contact surface shall have a >5mm radius; the bending radius of probe shall be comprised within 15 and 50mm (See ISO 4593).
9.2.2 Procedure. The number of sacks to be tested is indicated in Table 3. For each sack the measurements shall be done testing several points (at least 10) in a strip cut our along the circumference of a section perpendicular to the length of the sack. The average is then calculated.
9.3 Measurement of Mass. The mass is measured using specimens of 100cm3, withdrawn suing an hollow punch (UNI 8516). At least 10 specimens shall be withdrawn at regular intervals along the circumference of a section perpendicular to the length of the sack. The specimens are weighted and the average is determined.
9.4 Resistance to Dropping of the sacks filled with Matter. This test is aimed to verify the resistance of compostable sacks to dropping when filled with biowaste, which is a wet matter. Sacks are sampled by the batch in the amount indicated in Table 3, and filled up to _ of their height with wet wood shavings (ballast). The wood shavings shall be obtained from soft wood (such as fir, pine, larch) by planing or milling. Sawdust is not appropriate. Water is then added to reach the final mass indicated in Table 4. For sacks of the Class S the test load indicated in Table 4 is reached adding 1.5Kg. of sand to the wood shavings and then adding water to reach the final mass. Sacks are then tied with a string. The closure shall be done just above the ballast, removing the air without compressing the ballast. The loaded sacks are dropped from a height of 1.20 m on a flat smooth and hard test surface (i.e. concrete). The height is measured from the bottom of the sacks over the test surface. Each sack shall be dropped only once. After dropping inspect the sack for rupture.


 
  Table 4 Load to be applied to the sacks in the dropping test according to the dimensional class of the sacks:

 
 
CLASS DENOMINATION TEST LOAD (Kg.)
L1 Large size heavy duty 18
L2 Large size, normal duty 12
M Medium size 6
S Small size 3
 
 
9.5 Load Resistance and Watertight
Sacks are sampled by the batch in the amount indicated in Table 3, and loaded as indicated in 9.4. The loaded sacks are hooked at the top (at the mouth tie) and hung for 6 hours. The tie shall be done using a string having a diameter of not less than 2mm. At the end of the testing period sacks are verified for rupture and water and shavings leakage.
9.6 Tensile Properties
The test is done according to ASTM D 882, with a speed of 50mm/mim. Using preferably rectangular 10mm in width specimens, with a distance of the grips of dynamometer of 50mm. The number of sacks to be tested is indicated in Table 3. From each sack at least 5 specimens are obtained in the longitudinal direction, and 5 specimens in the cross direction, cut out regular interval along the circumference of a transversal section. The specimens shall be obtained using a hollow punch and conditioned at 23-2 C and 50=5% relative humidity for at least 24 hours. Tensile strength at break, percent elongation at break and Young Modulus shall be determined.
9.6.1 Tensile Strength at Break. The Tensile strength at break shall be expressed in Mpa, that is as the ratio of load to the original transversal section of the specimen. Determine the average values testing at least 5 specimens in the longitudinal direction and 5 specimens in the cross direction of the sack.
9.6.2 Percent Elongation at Break. Average percent elongation at break shall be determined testing at least 5specimens in the longitudinal direction and 5 specimens in the cross direction of the sack
9.6.3 Young Modulus. Determine the Modulus, given the ratio tensile strength/elongation, in the first part of the curve, where a linear relationship between load and elongation is present.
9.7 Tear Resistance. The measurement is done according to the Standard ASTM D 1938, with a speed of 250mm/min.. The number of sacks to be tested is indicated in Table 3. From each sack at least 5 specimens are obtained in the longitudinal direction, and 5 specimens in the cross direction, cut out at regular interval along the circumference of a transversal section.
The specimens shall be obtained using a hollow punch and conditioned at 23-2 C and 50=5% relative humidity for at least 24 hours. Determine the initial tear load and propagation tear load and express them as values normalized to the thickness. The normalization of results to the thickness is performed to permit comparisons of films slightly different in thickness. It is not appropriate for comparing films very different in thickness.
9.7.1 Initial Tear Load. The value of tear resistance is obtained by dividing the Load (N) by the film thickness (mm). The tear resistance shall be expressed in N/mm as the average of at least 5 specimens for each of the two main directions. The load (N) is achieved by the load-displacement curve ( Figure 1A and Figure 1B). If the discontinuity produced by the initial tear should not be evident in the load displacement curve, the value of the propagation tear load will be applied as the initial tear load value as well.
9.7.2 Propagation Tear Load. When the load-displacement curve is similar to Figure 1A , the tear load will be equal to the maximum load. On the other hand, when the load-displacement curve is similar to Figure 1B the tear load will be equal to the average load.The value of tear resistance is obtained by dividing the load (N) by the film thickness (mm). The tear resistance shall be expressed in N/mm computing the average of at least 5 specimens for each of the two main directions.
9.8 Composting
9.8.1 Disintegration Test. The sacks are sampled according to Table 3. Each sack is cut into about 2.5cm x 2.5 cm pieces. The pieces are pooled and mixed carefully. The amount of film needed to perform the disintegration test is withdrawn from its mass and treated as required. This test shall be performed as described in the CEN TC 261/SC4/WG2 draft test method.
9.8.2 Controlled composting test. The sacks are sampled according to Table 3. The sacks are properly milled. The test shall be performed as described in the CEN TC 261/SC4/WG2: Evaluation of the ultimate aerobic biodegradability and disintegration materials under controlled composting conditions-Method analysis of released carbon dioxide.

 
   
  10. Marking
The following marking shall be printed on each sack:
Name & Logo identification mark of the responsible supplier
CEN compostability label or other equivalent
Safety instructions including child protection rules
Date of productionLoad - displacement curves

 
Fig. 1A
L1
 
Fig. 2A
L1