- by Elay Plastic
- 02 August 2026
Type A, B, C and D FIBCs: What the Classification Means
A careful overview of electrostatic FIBC classifications, grounding and why the complete bag-and-liner system must match the hazardous environment.
Why electrostatic classification matters
Filling and emptying powders or granules can generate static electricity. If a combustible dust cloud, flammable gas or vapour is present, an energetic discharge may create an ignition risk. FIBC selection must therefore begin with a documented assessment of the product and the surrounding atmosphere.
IEC 61340-4-4:2018 covers electrostatic classification, testing and safe-use requirements for FIBCs intended for hazardous explosive atmospheres. The classification is not a general quality ranking from A to D.
Type A
Type A FIBCs provide no special electrostatic protection. They may be considered only where the packed material and surrounding environment do not create an electrostatic ignition hazard requiring a protective FIBC.
They must not be treated as suitable for combustible dust or flammable solvent atmospheres merely because the fabric appears similar to another bag.
Type B
Type B FIBCs are designed to prevent highly energetic propagating brush discharges, but they do not provide a controlled path to ground. Their safe use depends on the characteristics of the dust and the absence of an unsuitable flammable gas or vapour atmosphere.
The permitted operating conditions must be confirmed against the applicable standard and site risk assessment.
Type C
Type C FIBCs contain interconnected conductive elements and are intended to be grounded during filling and discharge. Grounding is an operating requirement, not an optional precaution. The connection, verification method and operator procedure must be reliable before product flow starts.
A Type C label does not compensate for a missing or ineffective earth connection. Compatible liners, labels and document pockets must also be part of the qualified system.
Type D
Type D FIBCs use dissipative construction intended to control electrostatic discharges without a grounding connection. Safe use still depends on the qualified bag design, compatible accessories and the defined environment.
Conductive contamination on the bag surface or nearby conductive objects can affect conditions of use, so the supplier’s instructions and site controls remain essential.
What a buyer must provide
State the minimum ignition energy of the dust where known, dust-cloud behaviour, presence and group of flammable gas or vapour, hazardous-area classification, process temperatures, filling and discharge rates, liner requirement and grounding capability.
The final selection should be approved by competent safety personnel and supported by the appropriate test evidence, certification and marking for the complete FIBC configuration. Do not substitute one FIBC type for another without a new assessment.
Relevant standards and guidance
- IEC 61340-4-4:2018 — electrostatic classification of FIBCs
- IEC TS 60079-32-1 — electrostatic hazards guidance
Important: Final suitability depends on the packed product, process, handling environment and approved technical specification. Consult the responsible safety or dangerous-goods specialist where applicable.