Bulk Bag Types and Labeling Requirements for Static Protective FIBCs

Posted by Chris Wheeler on July 22,2019

Last year we covered How to Choose the Right Type of FIBC Fabric in an article that went into depth about the different types of A, B, C, and D bulk bags. What you may not know is that depending upon which bulk bag type your facility uses, the International Electrotechnical Commission (IEC) specifies a requirement, IEC 61340-4-4:2018 for the classification and labeling of FIBC bulk bags. It also dictates the classification of inner liners as well as a gamut of other regulations put in place to ensure the safe use of electrostatically charged bulk bags. Let’s take a look at each bulk bag fabric type to understand the labeling required to keep you and your employees safe while handling FIBCs.

Type A Bulk Bags

Type A FIBCs are constructed using your standard bulk bag fabric which is a woven polypropylene blend.  Type A bags have no labeling requirements related to static charge because they are not intended for use with (or in proximity to) flammable products or combustible atmospheres. Type A bulk bags have no protective design measures against the buildup of static electricity.

Type B Bulk Bags

Type B FIBCs are made with insulating fabric with a breakdown voltage that does not exceed 6kV. Type B bulk bags are perfect for the safe transportation of dry, combustible powders and are effective for the prevention of explosive dust-air mixtures from igniting however, they are not able to dissipate static electricity so minor brush charges (<6kV)  may occur. This means Type B bulk bags should not be used in the presence of flammable solvents or gases.

Type B FIBC LabelLabeling Requirements for Type B Bulk Bags

Type B FIBC labels cannot be made from material with surface resistivity less than 1.0 x 109 Ohm. (The electrical resistance of an object is a measure of its opposition to the flow of electric current.)

Type B FIBC Label Must State:

  • Permitted in dust zones 21-22 with MIE > 3 mJ
  • Electrical property may be affected by general usage, contamination and reconditioning
  • All conductive objects including personnel shall be earthed during FIBC filling and emptying operations (see IEC TS 0079-32-1 for guidance on earthing)

Example of a Type B Label:

TypeBFIBCLabel2018

Type C Bulk Bags

A type C bulk bag is made to prevent the occurrence of sparks and discharges.  The fabric used in the construction of a Type C FIBC contains inter-connected conductive thread which must be electrically grounded during filling and discharging. This bag is also used to transport flammable powders but may be used safely in the presence of flammable solvents or gases when it is properly grounded.

Type C FIBC LabelLabeling Requirements for Type C Bulk Bags

  • Labels made from materials with Surface Resistivity <108 Ohm, can be used provided the resistance to groundable point is <1.0 x 108 Ohm
  • Labels made from materials with Surface Resistivity between 1.0 x 109 and 1.0 x 1012 Ohm, can be used
  • Type C FIBC labels with surface resistivity greater than 1.0 x 1012 Ohm measured according to IEC 61340-2-3 under the conditions specified in 8.2, shall not be greater than 100 cm2 in area, or greater than or equal to 700 µm in thickness

Type C FIBC Label Must State:

FIBC shall be properly earthed according to manufacturer’s instructions

  • Permitted in dust zones 21-22 and gas zones 1-2 (explosion groups IIA/IIB)TypeCEarthBondingPoint2018
  • Electrical property may be affected by general usage, contamination and reconditioning
  • All conductive objects, including personnel shall be earthed during FIBC filling and emptying operations (see IEC TS 0079-32-1 for guidance on earthing)

Designated earth bonding points on Type C FIBC shall be labeled or marked with earth symbol (IEC 60417-5-19).  Yellow background with black marks and lettering OR black background with yellow marks and lettering. The label or marking may be incorporated into another label or marking as may be required for other purposes.

One or more groundable points shall be permanently attached to Type C FIBC. Earth bonding cables shall be attached to the groundable points during all filling and emptying operations. 

Example of a Type C FIBC Label:

TypeCFIBCLabel2018

Example of Type C FIBC Label placement in use:

Type C FIBC Earth Bonding Label in Use

Type D Bulk Bags

A type D FIBC is manufactured from static protective fabric which contains interwoven static dissipative threads. The construction of the bag prevents sparks and discharges without the need for grounding but is not safe to use when the surface is contaminated or covered with products like water or grease that conduct electricity.

Type D FIBC LabelLabeling Requirements for Type D Bulk Bags

Type D FIBC labels >100cm2 in area shall be subjected to ignition testing. Printing ink can modify the surface electrical properties of labels. Therefore, measurements made to verify compliance with the requirements of Clause 6 shall be made on printed labels. Printed and unprinted surfaces of labels shall comply with the surface resistivity requirements of Clause 6. 

Type D FIBC Label Must State:

FIBC does not require earthing

  • Permitted in dust zones 21-22 and gas zones 1-2 (explosion groups IIA/IIB with MIE > 0.14mJ) and where charging currents ≤3 µA
  • Electrical property may be affected by general usage, contamination and reconditioning
  • All conductive objects including personnel shall be earthed during filling and emptying operations (see IEC TS 0079-32-1 for guidance on earthing)

Example of a Type D FIBC Label:

TypeD-full

General Labeling Requirements for all Bulk Bag Types:

  • Yellow background with black marks and lettering OR black background with yellow marks and lettering. Yellow is preferred for the background color for labels or marking, but other colors may be used. Conductive black material may be used for labels for Type C FIBC, but shall not be used for labels for Type B or Type D FIBC.
  • FIBC is not to be labeled or marked in any way that conflicts with international standard (e.g. Type CD or D+ is not permitted)
  • The FIBC manufacturer is responsible for ensuring that the production FIBC (to which the label will be attached) is the same as the tested samples.

FIBC Inner Liner Types and Requirements

Type L1

Made from materials with “Surface Resistivity” on at least one surface ≤1.0x108 Ohm, measured according to IEC 61340-2-3.

Requirements:
  • If the material is multi-layered, or if the material has one surface with Surface Resistivity >1.0x1012 Ohm, “Breakdown Voltage” through the material shall be < 4KV
  • Surface with resistivity less than 1.0 x 108 Ω shall be securely connected to the earth bonding system of the FIBC via specific connections.

Type L1 C

Made from multi-layered materials with an internal layer of surface resistivity less than or equal to 1.0 × 108 Ω (see Annex F). Type L1C inner liners may be used in Type C FIBC

Requirements:
  • The breakdown voltage between any surface with resistivity greater than 1.0 × 1012 Ω and the conductive internal layer shall be less than 4 Kv
  • All layers with surface resistivity less than 1.0 × 108 Ω shall be securely connected to the earth bonding system of the FIBC via specific connections

Type L2

Made from materials with “Surface Resistivity” on at least one surface between 1.0x109 and 1.0x1012 Ohm, measured according to IEC 61340-2-3.

Requirements:
  • If the material is multi-layered, or if the material has one surface with Surface Resistivity >1.0x1012 Ohm, “Breakdown Voltage” through the material shall be < 4KV
  • Thickness of any layer with Surface Resistivity >1.0x1012 Ohm per Square on the inside of the liner shall be <700 micrometer
  • Surface with resistivity between 1,0 × 109 Ω and 1,0 × 1012 Ω shall be securely connected to the earth bonding system of the FIBC via specific connections

Type L3

Made from materials with “Surface Resistivity” greater than 1.0x1012 Ohm, measured according to IEC 61340-2-3

Requirement:

“Breakdown Voltage” through the material shall be less than 4KV

Permissible FIBC Liner Combinations

Always check with your FIBC manufacturer that your static protective FIBC is fitted with the correct anti-static liner before handling. The chart below is only a general guideline. Always reference the current IEC standard for all of the requirements. Inner liners and FIBC: combinations that are permissible and not permissible in hazardous explosive atmospheres:

FIBC INNER LINER
Type L1 Type L1C Type L2 Type L3
Type B Not Permissible Not Permissible Permissible Permissible
Type C Permissible Permissible Permissible Not Permissible
Type D Not Permissible Not Permissible Permissible Not Permissible

It is important to always reference the ISO standard for the current requirements.

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Tags: Flexible Packaging

Chris Wheeler
ABOUT:

Chris Wheeler

Material Science Engineer at Conitex Sonoco

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