Type A, B, C and D
FIBC electrostatic classification, explained without the jargon — and how to choose without getting it wrong.
Filling a bag generates static electricity. Depending on your product and your plant atmosphere, that charge is either harmless… or the spark inside a dust cloud. That is exactly why the four types exist.
Type A — no protection
Standard polypropylene fabric with no antistatic treatment. Suitable only for non-flammable products, with no solvents and no explosive atmosphere present. The most common bag, and the least expensive.
Type B — limited discharges
Low breakdown voltage fabric (under 6 kV) that prevents high-energy propagating brush discharges. For dry flammable powders, provided no flammable gas or solvent is present. Note: Type B is not antistatic — it only limits discharge energy.
Type C — conductive, grounding mandatory
Conductive threads woven into the fabric, bonded to a ground point. The bag must stay grounded throughout filling and discharge. The standard where flammable gases or vapours are present. An ungrounded Type C is more dangerous than a Type A.
Type D — dissipative, no grounding
Fabric that safely dissipates charge without a ground connection. The answer when grounding cannot be guaranteed on the floor — rotating crews, multiple sites, high throughput. More expensive, but it removes human error.
The decision shortcut
Is your product flammable? If no, Type A. If yes: are flammable gases or solvents present in the atmosphere? If no, Type B. If yes, Type C (with rigorous grounding) or Type D (if you cannot guarantee grounding).
This shortcut does not replace a risk assessment. Your safety officer or process engineer makes the call, based on your hazardous area classification and internal standards. We supply the bag specifications; we cannot classify your working atmosphere for you.
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