How to define your FIBC depends
  1. Product

    1. Volume is calculated as D=Mass/Volume (= gram/cc (cubic cm)) and the volume of the FIBC will be depending on the density of the product that is to be filled. Problems occur when the bag is not filled correctly:

      • Too large volume: as the bag will not be filled completely, the side walls of the bag will bulge more, leading to a deformation of the FIBC with negative effect on stability
      • Too small volume: over-spilling of the product as the bag cannot take the required batch or needed load


    2. The exact definition of the raw material will be needed in order to adjust the concept of a conductive FIBC. Either a TYPE B bag or TYPE C bag will be recommended. TYPE D as well feasible (MPG is Cromic Blue licensee).

    3. In case that after filling process the product produces gases inside the bag, a valve will be needed in order to diminish the pressure (see ’MPG Valving systems’).

    4. Protection against humidity or oxygen required? Possibilities range from an 80-100 Micron PE liner to co-extruded liners with multilayer barriers or Aluminium liners that can enhance protection for highly microscopic final product that need higher barrier against CO2 or H2O.


  2. Filling/Discharge facilities and handling

    1. Filling facility:
      • Is there already existing filling equipment for FIBCs?
      • If not, are they willing to invest in such equipment?
      • If yes, are there any restrictions, i.e. height?


    2. Discharge facility:
      • Has the factory different requirement with different restrictions for discharging?


    3. From factory to factory:
      • Are there any further restrictions while handling the filled big bag? I.e. narrow doors, restricted space for turning with forklift, etc
      • Warehousing is adapted for storing and handling FIBCs?
      • Is a slip sheet solution required? This will need further special handling equipment that needs to be analyzed at both parties’ factories.


  3. Technical Issues of an FIBC

    1. Dimensions: depending on product specifications, a base dimension to fit on standard Euro-pallets (100x120 cm) should not exceed the pallet after filling. Due to elongation of the PP fabric the volume of a bag will increase after filling and is usually calculated according to the following formula:

      L x W x H = VOL (theoretical Volume without elongation)

      VOL’ = VOL X 1.15 (real Volume with i.e. 10-15% elongation)

      Below listed points will affect the elongation factor, for an assumed FIBC with liner:

      • the thickness of the outer PP fabric (160-240 g/m2)
      • coating of the outer PP fabric (30 g/m2)
      • liner thickness (80-100 mic)
      • liner material (Aluminium, Multi-barrier, LDPE, HDPE)
      • Inner liner with baffles or without baffles

      The stronger the outer fabric (in gr/m2) and if the bag has an inner liner with baffles, the less will be the elongation factor and therefore the real volume (VOL’) will stay closer to the theoretical volume (VOL) of the bag. Elongation factors can range from 8-10% for bags with baffled liners (PowerQubes) and up to 15% for bags without liners.

    2. SWL and SF: The Safety Working Load (SWL) is the maximum load that will be filled into the big bag. The usage cycles (single trip vs. multi trip) of the big bag will define the Safety Factor (SF) to be applied. I.e. if the load is 1000 KG of product and the usage single trip, the definition will be SWL 1000 / SF 5:1. This implies that the fabric to be used shall resist the sum of one load with 5 times more weight: 6000 kg.

    3. Filling: Standard filling spouts have 30 cm diameter and 50 cm length, but diameter and length can be adjusted (25-60cm diameter are possible).

    4. Discharge: Standard filling spouts have 30 cm diameter and 50 cm length (variations possible, see c) and are recommended to be closed by swan-neck knots.

    5. Loops: Depending on the usage, either side-seam loops or over-the-corner loops (cross-corner) are standard. The length varies from 15-40 cm and the width of the used loops is according to the SWL and SF required (see b)).

    6. Inner liners: Masterpack Group’s standard liners are unique and sewn on the top and the bottom of the big bag all around the perimeter seams and are of modular construction, with following advantages:

      • no contamination between the liner and the outer PP bag
      • form-shape liner fitting like a ’second skin’ into the outer PP bag
      • no twisting of the liner inside the PP bag
      • no pre-blowing of liner necessary
      • no risk of loosing the liner during discharge

    7. Hygienic bags: For achieving highest hygienic standards it is recommended to use a bag with liner (see f)) since only an inner liner can be produced in absolute hygienic conditions, i.e. Masterpack produces liners up to class 10.000.

      Additionally, if an FIBC has to run through different hygienic zones, i.e. BHZ (Basic Hygienic Zone), MHZ (Middle Hygienic Zone) and HHZ (High Hygienic Zone), than the concept of an outer strippable cover can be recommended (see ’MPG Hygienic systems: Strippable Bag’).
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