What is BS EN IEC 60079-11:2024 - Equipment protection by intrinsic safety about?
This revised international standard is Part 11 in a series on making explosive atmospheres safer. BS EN IEC 60079-11:2024 specifies how to construct and test intrinsically safe apparatus.
Who is BS EN IEC 60079-11:2024 - Equipment protection by intrinsic safety for?
Hazardous area equipment designers and manufacturers
What does BS EN IEC 60079-11:2024 - Equipment protection by intrinsic safety cover?
This part of IEC 60079 specifies the construction and testing of intrinsically safe apparatus intended for use in explosive atmospheres, and for associated apparatus that will be connected to intrinsically safe circuits entering such atmospheres.
This type of protection applies to electrical equipment in which the electrical circuits themselves are incapable of causing ignition of a surrounding explosive atmosphere. This includes electrical equipment that contains circuits that are intrinsically safe only under certain conditions, for example under battery supply with mains supply removed.
NOTE: BS EN IEC 60079-11:2024 supplements and modifies the general requirements of BS EN IEC 60079-0. Where a requirement of this document conflicts with a requirement of BS EN IEC 60079-0, the requirement of this document takes precedence. Requirements for intrinsically safe systems are provided in BS EN IEC 60079-25.
Why should you use BS EN IEC 60079-11:2024 - Equipment protection by intrinsic safety?
- It reduces the risk of explosions in explosive atmospheres
- It can develop the user’s expertise with intrinsically safe apparatus
- It can increase confidence in the safety of intrinsically safe apparatus
- Its use strengthens risk management
- The revisions make for a clearer, more user-friendly, more correct document
- This standard is due to be listed in the ATEX OJ and UKCA designated standards list so can be used to show that products comply with essential requirements in legislation
BS EN IEC 60079-11:2024 contributes to UN Sustainable Development Goal 9 on industry, innovation and infrastructure.
What’s new about BS EN IEC 60079-11:2024?
BS EN IEC 60079-11:2024 is a general update of BS EN 60079-11:2012 that attempts to resolve differences in application and clarify the requirements of the previous edition. The standard has also been re-arranged to ensure requirements are in the requirements section, tests are in the test section etc.
The significant changes between BS EN IEC 60079-11:2024 and IEC 60079-11, Edition 6 (2011 + Corrigendum 1 (2012)) are as listed below:
· A significant number of editorial changes including restructuring of sections.
· Protection of catalytic elements for Group IIC or Group IIB + H2 excluded from the scope of the standard.
· Clarification relating to the application of service temperatures.
· For Level of Protection "ic", faults are only considered for spark ignition assessment and the determination of Uo, Io, Li , Ci and Li /Ri . A short circuit fault, and subsequent component faults arising, are now termed non-countable faults.
· Clarification of the requirements for circuits with controlled semiconductor limitation, including need to consider both steady state and transient spark ignition compliance for circuits with controlled semiconductor limitation.
· The 5K and 10K margin required for temperature tests from IEC 60079-0 now apply for Level of Protection "ic".
· Corrected the formula for thermal assessment of wires.
· Clarification that the IEC 60079-0 enclosure requirements apply for Group IIIC equipment with separations according to Table 7 (Ed 6 Table 5) that are reliant on an enclosure providing IP5X.
· Requirement for a Specific Condition of Use added when use of reduced separations is reliant on an enclosure providing IP54.
· Conductors, connectors and PCB tracks have to be suitably rated for their failure to be a countable fault.
· It is now a stated requirement that circuits remain intrinsically safe after disconnection of a connector.
· It is now a requirement that infallible connections remain capable of carrying the current following considered fault disconnections.
· Infallible PCB connection achieved with two 1mm wide tracks now have copper thickness requirements.
· Dielectric strength requirements have been clarified in Table 8 – Reduced separations.
· Specific Condition of Use required when OVC II/I is required for mains apparatus when using Table 9 - Reduced separations for Level of Protection "ic".
· Determination of type and routine testing required when using reduced separations tables.
· Where metal parts connected to the frame or earth are used to separate two circuits, a Specific Condition of Use is now required.
· Clarification that separation by metal parts requires infallible connection.
· Routine verification of encapsulation added.
· The specified COT for encapsulation shall not be exceeded in normal operation. Tighter requirements for damage to compound for temperature greater than COT.
· Requirements for specification of coating, encapsulation and moulding materials.
· Components for Level of Protection "ic" are considered to fail if they are not within their manufacturer's rating following the application of faults.
· Resistors of types not listed (film, wire wound and printed) cannot now be considered to fail as a countable fault, nor to limit their own temperature.
· Cold resistance of a fuse, filament of a bulb or infra-red source is assessed at the service temperature rather than the ambient temperature.
· Clarification that assessment of semiconductors cannot be based on failure rates.
· Clarification of the requirements for programmable components.
· Clarification that the requirement for mains transformers includes any transformer that is not galvanically isolated from the mains.
· Requirements for transformers for Level of Protection "ic" added.
· Countable fault separation between the coil and contacts of a relay is no longer permitted.
· Clarification that the cold resistance of a fuse cannot be used to limit the breaking current.
· A fuse in Level of Protection "ic" shall be considered an ignition risk if its opening is an expected occurrence.
· Clarification that temperature rise and electrolyte leakage should be considered for cells.
· Clarification that short circuit of a single cell is considered a non-countable fault.
· Clarified that thermal assessment of catalytic sensors shall take into account heating due to the catalytic reaction.
· Clarification that supercapacitors shall be treated as batteries with a limited capacity but without the ability to limit their own voltage.
· Requirements and tests for thermal devices added, including PTCs.
· Clarified that the effect of temperature on an inductor's resistance shall be taken into account during spark testing.
· Clarified that the current shall be continuous when discharging during the tests.
· Electrolyte leakage and surface temperature test requirements for cells and batteries modified to cover the number of samples tested, the test temperature, and testing with dust layers.
· Requirement added to consider the spark ignition risk of single lithium cells of less than 4,5 V with high short circuit current.
· Transformers for Level of Protection "ic" shall be routine tested where there is no applicable industrial standard, or the applicable industrial standard does not specify a routine test.
