An FIBC specification should state the bag type (A to D), the dimensions, the safe working load and safety factor, the fabric GSM and coating, the loop type and count, the top and bottom design, any liner, printing, UV stabilisation, whether the bag is food grade, the certification required, the packing and the test certificates you expect with each shipment. If each of these is written down, the plant can quote accurately, the inspector can check against it and any dispute has a reference. If any of them is missing, the plant will make an assumption and that assumption may not suit your product.
The specification does not need to be long. One page with a drawing is enough for most bags, and a plant will often send you its own template to fill in.
Bag type and safety
Start with the type. Type A is plain polypropylene with no static protection, Type B uses fabric with a limited breakdown voltage to prevent energetic discharges, Type C is conductive and must be earthed during filling and emptying, and Type D dissipates static without earthing. If your product is a flammable powder or will be used in an explosive atmosphere, the type matters more than any other line in the document.
Then state the safe working load, usually a figure such as 500, 1,000 or 1,500 kg, and the safety factor, 5:1 for single trip and 6:1 for multi trip, with reference to EN ISO 21898 or IS 16709.
Construction details to include
- Dimensions: base width and length, filled height, and the tolerance you will accept.
- Fabric: GSM of the body fabric and any bottom panel, coated or uncoated, and the colour.
- Loops: corner loops, cross corner loops or a single loop design, the loop length and the webbing width.
- Top: open top, duffle top or filling spout with its diameter and length.
- Bottom: flat bottom, discharge spout with closure type, or a full open bottom.
- Liner: material, thickness, whether loose, tabbed or glued, and whether it is form fit.
- Baffles: whether required, and the baffle fabric specification.
- Printing: number of colours, print area and sides, with the artwork attached.
- UV stabilisation: the UV package and the expected outdoor exposure period.
- Food grade: yes or no, and if yes the cleanroom and certification standard such as BRCGS.
Testing, packing and documentation
State the tests you expect and how often. A top lift test to the stated safety factor is the minimum, with cyclic and drop tests where the handling is rough, and you should say whether you want batch test reports with each shipment or a periodic report. Add the packing requirement: bags per bale, bale wrapping, pallets or loose, ISPM 15 marking for wooden pallets, and the bale labelling you need.
Finish with the documents: a certificate of conformity to the specification, the test reports, the ISO 9001 certificate of the plant and, for food grade, the BRCGS or equivalent certificate. Give the specification a version number and a date, and refer to that version in every purchase order so there is never a question about which one applies.
What Creston & Co does
We draft or review the specification with you before any plant sees it, so that the quotes come back on the same basis and the inspection has something to check against. We then audit the plant, witness the lift tests, inspect before shipment and supervise loading, with a weekly update throughout. If you have a specification already, send it over for a free 20-minute sourcing review and we will tell you what is missing.