Safety Work Load & Safety Factor of FIBCs
SWL - SAFETY WORK LOAD - MAXIMUM CARRYING WEIGHT OF A FIBC BAG
FIBC are designed for a specific Safety Work load (SWL). Common SWLs are 500kg, 1000kg, 1200kg, 1250kg, 1500kg or 2000kg. The SWL is determined by the customer. Often the Safety work load is chosen to achieve a maximal load weight on a truck. Depending on the size of the FIBC bag they often have a SWL of 1000 or 1250kg. A higher SWL results in stronger FIBC fabric used.
SF - SAFETY FACTOR - ONE TRIP vs MULTI TRIP FIBC BAGS
Some woven polypropylene FIBC bags are manufactured for one-time use. These one-time use bags are rated at a 5:1 safety factor (SF) meaning that the FIBC bag did burst only after reaching five times its safety work load (SWL) in the test rig. A 1000kg FIBC bag did therefore burst on more than 5t load. A 2000kg FIBC bag bursts after 10t load in the test rig.
One-time FIBC bags cannot be “repaired”. It’s not allowed to reuse these FIBC bags.
2. Multi trip FIBC bags
Sometimes a multi trip FIBC bag is more economical than a single trip one. This is usually the case when all big bags are emptied at the same place and can be easily collected. Furthermore, it should not be a food FIBC bag. In this case the FIBC bags can be returned to the filling place and reused for a limited number of times. These multi trip FIBC bags are constructed stronger and achieve a safety factor (SF) of 6:1 which means that the FIBC bag did burst after more than six times its safety work load (SWL) during testing. On multi trip FIBC bags an additional multi trip label can be added to count the number of circles. multi trip FIBC cannot be used infinite times. However, there is no rule how often they should be used.
Multi trip FIBC bags cannot be repaired. Damaged multi trip FIBC bags must not be used. It is not allowed to fill in different materials into the FIBC on its different trips.
Sometimes a multi trip FIBC bag is more economical than a single trip one. This is usually the case when all big bags are emptied at the same place and can be easily collected. Furthermore, it should not be a food FIBC bag. In this case the FIBC bags can be returned to the filling place and reused for a limited number of times. These multi trip FIBC bags are constructed stronger and achieve a safety factor (SF) of 6:1 which means that the FIBC bag did burst after more than six times its safety work load (SWL) during testing. On multi trip FIBC bags an additional multi trip label can be added to count the number of circles. multi trip FIBC cannot be used infinite times. However, there is no rule how often they should be used.
Multi trip FIBC bags cannot be repaired. Damaged multi trip FIBC bags must not be used. It is not allowed to fill in different materials into the FIBC on its different trips.
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