Conductive Jumbo Bags
WHY CONDUCTIVE BIG BAGS?
During filling and discharging of polypropylene woven bags the material rubs against the fabric and electric charges emerge. When it comes to an electric discharge it is possible that explosive environment or materials inflame. In order to prevent this, there are special conductive big bag types (or antistatic big bags) that are used in explosive environments and explosive products. Their properties are standardised in IEC 61340-4-4 Ed. 2.0.
Generally, there are two situations that bear danger:
Explosive materials – When explosive materials are filled into big bags the usage of conductive big bags is determined by the minimum ignition energy of the materials.
Explosive Environment – An explosive environment can be given by dust, gases or steam. The highest danger is given when the explosive environment consists of gases or steam.
|Non-explosive environment||Explosive dust
(Dust Zone 21-22)
|Explosive gases or steam
(Gas Zone 1-2)
|non explosive||A, B, C, D||B, C, D||C, D|
|MIE > 3mJ||B, C, D||B, C, D||C, D|
|MIE < 3mJ||C, D||C, D||C, D|
MIE (minimum ignition energy), mJ (mega Joule)
TYPE A BIG BAGS
The big bags have no special electrical properties. Most of the big bags that are used in the industry are Type A big bags. When nothing else is mentioned than a big bag is Type A.
TYPE B BIG BAGS
Type B big bags are made from a Type B fabric which has a breakthrough voltage less than 6KV. This reduces the chance of heavy discharges.
The difference between Type A & B FIBCs is Type B are made from materials that have a low breakdown voltage to prevent an incident where highly energetic, and dangerous propagating brush discharges occur. Although Type B bulk bags can prevent propagating brush discharges, they are not considered anti-static bulk bags because they do not dispel an electrostatic charge.
TYPE C BIG BAGS (CONDUCTIVE BIG BAGS)
Type C big bags are fully conductive. They have black conductive carbon threads that are woven into the fabric. Additionally are all parts of the big bag connected with conductive interconnections so the resistance between any parts is less than 107 ohm.
Type C big bags have black grounding points of which one must be grounded during filling and discharging. Alternatively some filling and discharging rigs can ground the Type C FIBC via the loops. Electrical loads on the big bag are effectively eliminated when using Type C FIBC.
TYPE D BIG BAGS
Type D FIBCs are made from antistatic and static dissipative fabrics designed to safely prevent the occurrence of incendiary sparks, brush discharges and propagating brush discharges without the need for a connection from the FIBC to a designated ground/earth. Type D big bag is used to transport flammable powders or when flammable vapors, gases, or combustible dusts are present.
Do not use type D bulk bags when surface of FIBC is contaminated or coated with conductive material such as grease or other flammable and or combustible materials.
Big Bags with Inliners can also be constructed with special conductive Inliners.
LABELLING CONDUCTIVE BIG BAGS
Conductive big bags are labeled with a yellow extra label which contains some relevant information.
TESTING CONDUCTIVE BIG BAGS
We are measuring both breakdown voltage and conductivity of the fabric and the finished Conductive big bags.
WHAT HAPPENS IF I DON´T USE THE PROPER CONDUCTIVE FIBC?
If no proper bulk bag is used correctly, in the worst case, it can come to an explosion in your or your customer’s factory. This may not only lead to financial damage but also to personal damage. Luckily, so far with An Vinh Packaging customers, no major accident with discharges from FIBC ever happened.