IEC 61340-4-4:2018 specifies requirements for flexible intermediate bulk containers (FIBC) between 0,25 m3 and 3 m3 in volume, intended for use in hazardous explosive atmospheres. The explosive atmosphere can be created by the contents in the FIBC or can exist outside the FIBC. The requirements include:- classification and labelling of FIBC;- classification of inner liners;- specification of test methods for each type of FIBC, inner liner, labels and document pockets;- design and performance requirements for FIBC, inner liners, labels and document pockets;- safe use of FIBC (including those with inner liners) within different zones defined for explosion endangered environments, described for areas where combustible dusts are, or can be, present (IEC 60079-10-2), and for explosive gas atmospheres (IEC 60079-10-1);- procedures for type qualification and certification of FIBC, including the safe use of inner liners. This third edition cancels and replaces the second edition, published in 2012, and Amendment 1:2014. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) in light of experimental evidence, the maximum resistance to ground limit for Type C FIBC, and corresponding resistance limits for inner liners used in Type C FIBC has been increased from 10 M ohms to 100 M ohms; b) the classification of Type L1 inner liners has been revised and extended to include Type L1C inner liners made from multi-layer materials with a conductive internal layer; c) a labelling requirement to include a reference to IEC TS 60079-32-1 for guidance on earthing has been added.