IEC 61340-4-4:2012 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 may be created by the contents in the FIBC or may 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 and inner liner;
- design and performance requirements for FIBC and inner liners;
- 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 may 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.
The requirements of this standard are applicable to all types of FIBC and inner liners, tested as manufactured, prior to use and intended for use in hazardous explosive atmospheres: Zones 1 and 2 (Groups IIA and IIB only) and Zones 21 and 22. For some types of FIBC, the requirements of this standard apply only to use in hazardous explosive atmospheres with minimum ignition energy of 0,14 mJ or greater and where charging currents do not exceed 3,0 μA. Compliance with the requirements specified in this standard does not necessarily ensure that hazardous electrostatic discharges, e.g. cone discharges, will not be generated by the contents in FIBC. Compliance with the requirements of this standard does not mitigate the need for full risk assessment. For example, metal and other conductive powders and toner powders may require additional precautions to prevent hazardous discharges from the powders. Test methods included in this standard may be used in association with other performance requirements, for example when a risk assessment has shown the minimum ignition energy of concern is less than 0,14 mJ, charging currents are greater than 3,0 μA, or the ambient conditions are outside of the range specified in this standard. Compliance with the requirements specified in this standard does not necessarily ensure that electric shocks to personnel will not occur from FIBC during normal use. This second edition cancels and replaces the first edition, published in 2005, and constitutes a technical revision. The main changes with respect to the first edition are listed below:
a) Adoption of a type classification system for FIBC based on four types: A, B, C and D.
b) Guidance for safe use of FIBC in relation to hazardous areas and hazardous zones defined in IEC 60079-10-1 and IEC 60079-10-2 is added.
c) Resistance to groundable points and electrical breakdown voltage measurements on FIBC shall be measured at low humidity only.
d) Requirements for labelling FIBC are changed to improve clarity and ease of recognition by end users.
e) Classification, performance requirements and guidance for safe use of inner liners in combination with FIBC are added.
f) An informative annex giving guidance on test methods for quality control and inspection testing is added.