IEC 60079-5:2015

Overview

IEC 60079-5:2015 - "Explosive atmospheres – Part 5: Equipment protection by powder filling 'q'" specifies construction, testing and marking requirements for electrical equipment and Ex components in the type of protection powder filling 'q' intended for use in explosive gas atmospheres. This 4th edition (2015) is a technical revision that supersedes the 2007 edition and supplements the general requirements of IEC 60079-0. Where this standard conflicts with IEC 60079-0, IEC 60079-5 takes precedence. The standard applies to equipment with rated supply current ≤ 16 A, rated voltage ≤ 1000 V and rated power ≤ 1000 W. Type “q” typically provides Equipment Protection Levels EPL Gb or Mb.

Key topics and requirements

The standard covers practical and testable requirements including:

• Constructional requirements
  • Definition and design of the container (housing) and sealing/closing arrangements
  • Filling procedures and handling of powder filling material
  • Material specification and documentation for filling media
• Clearances and distances
  • Required distances through filling material and surrounding free space to prevent ignition
  • Rules for creepage distances and reduced distances in specific situations
• Temperature limitations
  • Maximum temperatures for overload and fault/malfunction conditions and protective measures (fuses, temperature-limiting devices)
• Verifications and tests
  • Type tests (pressure test of container, dielectric strength test of filling material, maximum temperature verification)
  • Routine and batch tests (routine pressure and dielectric tests)
  • Degree of protection (IP) verification for enclosures
• Marking and instructions
  • Mandatory marking and user instructions specific to powder-filled Ex equipment
• Annex A
  • Alternative risk assessment method relating EPLs to hazardous zones

Practical applications and users

IEC 60079-5 is used by:

• Manufacturers and designers of intrinsically safe modules, transformers, relays, fuses, control gear and other Ex components that can be powder-filled
• Certification bodies and testing laboratories performing type and routine testing
• Safety engineers, procurement and maintenance teams specifying compliant equipment for explosive gas atmospheres (chemical, oil & gas, petrochemical, mining)
• Compliance officers aligning product design with IEC 60079 series requirements

Typical items covered include electronic circuits, transformers, protection fuses, relays, intrinsically safe apparatus, switches and associated electrical apparatus when protected by powder filling.

Related standards

• IEC 60079-0 (general requirements)
• IEC 60079-1 (flameproof "d"), IEC 60079-7 (increased safety "e"), IEC 60079-11 (intrinsic safety "i")
• IEC 60529 (IP codes), IEC 60127 (miniature fuses) and transformer safety standards referenced for specific tests

Keywords: IEC 60079-5, explosive atmospheres, powder filling "q", equipment protection, Ex components, EPL Gb, EPL Mb, electrical equipment.