The Flexible Intermediate Bulk Container (FIBC) causes an electrostatic charge of equal intensity, on the inner surface, but with
FIBCs are very large fabric bags supported in a frame. They are more convenient than rigid IBCs (Intermediate Bulk Containers) for powder transfers because they can be fully collapsed after use, taking up little storage space. The fabric used is usually polypropylene and is sewn to form a three-dimensional cube or rectangle with lifting straps. An FIBC can be filled with a powder or granular material and moved about with conventional handling equipment (forklifts, etc.).
An advantage of FIBCs is that they can be unloaded quickly, typically 300kg to 500kg in 30 seconds or less. It is common under these circumstances for the rates at which static electric charges are generated to exceed the rates at which the charges can relax, accumulation of a static electric charge is developed during the process. If the accumulated charge is strong enough and is released in the presence of a combustible atmosphere, ignition can occur. Static charges can be generated both during the filling and emptying of FIBCs. These discharges exhibit effective energies of as much as several Joules.
Where a static electric charge accumulates on FIBCs or associated process equipment, the following four types of discharges can occur:
- Spark Discharge
- Brush Discharge
- Propagating Brush Discharge
- Bulking Brush Discharge
The risk of electrostatic discharges in FIBCs in potentially flammable atmospheres is well documented in best practice standards / recommended codes.
The important Recommended Code of Practice and International Standard specifies procedures for FIBC that must be grounded, promoting a maximum 7 resistance of 1.0 x 10 ohms (10 meg ohms) for Type C FIBC bags. This provides EX/HAZLOC industry participants with a clear benchmark to target as a safety function when grounding protection against the accumulation of static electricity is a critical fire and explosion prevention measure.
Types of FIBC Bags
Type A FIBC bags are generally made from plain polypropylene or other nonconductive material.
It is essential that they are not used to store or transport combustible materials or used in flammable or combustible environments.
Type B FIBC bags are made from materials that have a low breakdown voltage, which helps prevent the occurrence of propagating brush discharges.
Only to be used when transporting ‘dry’ flammable powders in the absence of a flammable atmosphere around the bag.
Type C FIBC bags are designed to dissipate static electricity through static dissipative or conductive threads that are interwoven through the bag’s material. The Type C FIBC bags usually have conductive grounding tags located on both the top section and bottom section of the bag.
When using these bags in hazardous areas and/or for
Type D FIBC bags are made from static protective fabric designed to prevent the occurrence of incendiary sparks, brush discharges and propagating brush discharges.
At regular intervals, the user sends one sample of each Type D FIBC bag for re-qualification. Bags with surface contamination of conductive material, such as water or oil, should not be used.
Earth-Rite FIBC is Hazardous area certified
The monitoring control unit and power supply unit are ATEX / IECEx / cCSAus approved. The Earth-Rite FIBC has been given a SIL (Safety Integrity Level) of rating 2.To read more about the safety measures surrounding different bag types, the use of FIBC bags in industry and the Earth-Rite® FIBC solution from Newson Gale, click here to download the full application spotlight >
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