FIBC Design & Construction types
Cyclic Testing for Bulk Bags
Cyclic Top lift test requires the filled bag to be hanged from its lift loops on a test rig or other lifting devices as weight is added from the top.
If any of the body fabric or lift loops of the bags are damaged in this process, the bag is deemed to fail the test.
- For 5:1 SF, Cyclic top lift test requires the bags to go through 30 cycles @ 2X SWL (Safe Working Load) with a final cycle @ 5x SWL for final approval. For example, a 1000 KG, 5:1 bag will be subject to 30 cycles of load @ 2 X 1000 KG, and in the 31st cycle, the pressure will be increased continuously until the bag is ruptured or damaged. The ruptured or damaged load will be more than 5000 KG.
- For 6:1 SF, Cyclic top lift requires the bags to go through 70 cycles @ 4X SWL (Safe Working Load) with a final cycle @ 6x SWL for final approval. For example, a 1000 KG, 6:1 bag will be subject to 70 cycles of load @ 4 X 1000 KG, and in the 71st cycle, the pressure will be increased continuously until the bag is ruptured or damaged. The ruptured or damaged load will be more than 6000 KG.
Below is a comparative table to understand the differences between 5:1, 6:1 and 8:1 safety factor of the bag.
In the compression test, a dead load of 4 times the SWL of the bag is placed on top of the bag for 6 hours. If this load cause any damage to the bag, the test is considered as failed.
FIBC Drop Test*
The Bulk Bag is filled with a material similar to one being filled in reality up to 95% of the SWL of the bag. The filled bag is dropped onto a rigid surface from a height of 2.6 feet or 3.9 feet depending upon the classification of the bag. The bag should not lose out any material.
In the tear test, a 10 cm knife cut is given to bag at an angle of 45 degrees. The bag is filled to twice the capacity of the bag and then lifted and held in place for five minutes.
For the test to be passed, the cut size should not expand more than 2.5 cm.
* The criteria may not apply to all bag categories but special bags like UN Bags.
Ultra Violet Radiation
The Bulk Bags are manufactured by Woven Polypropylene fabric very robust. However, over a long time, the UV radiation of the sun can weaken the structure of the bag. Remember, that bulk bags can lift up to 2000 KG of material. Polypropylene is a very reliable material, but you should avoid anything that could potentially weaken a material expected to bear over a thousand kilo of weight. Below is a map showing the extent of UV radiation on earth surface.