IEC 60079-2:2014

Overview

IEC 60079-2:2014 - Explosive atmospheres - Part 2: Equipment protection by pressurized enclosure "p" (Edition 6.0, incl. corrigendum July 2015) defines specific construction, testing and marking requirements for electrical equipment with pressurized enclosures, type of protection "p", intended for use in explosive gas atmospheres and explosive dust atmospheres. This standard supplements and modifies the general requirements of IEC 60079-0 and takes precedence where conflicts occur. It is a technical revision that replaces IEC 60079-2 (2007) and IEC 61241-4 (2001).

Key topics and technical requirements

• Scope and exclusions: Covers pressurized enclosures for Group I, II and III atmospheres, including enclosures with a limited internal release of flammable substance. Excludes pressurized rooms/analyser houses (see IEC 60079-13), enclosures releasing oxygen-rich gas (>21 %), hybrid gas/dust mixtures, pyrotechnic/explosive/pyrophoric environments and enclosures with internal combustible dust sources.
• Constructional requirements: Enclosure design, materials, doors/covers, mechanical strength, sealing, spark/particle barriers and insulation for Group I equipment.
• Pressurization techniques: Static pressurization, continuous flow (leakage compensation and dilution), selection of protective gas (air or inert), temperature considerations and supply arrangements (backup and independent supplies).
• Containment and internal sources: Design of infallible containment systems, containment systems with limited release, and criteria when a pressurized enclosure contains a limited flammable release.
• Safety devices and sequences: Requirements for safety devices, minimum overpressure detection, sequences for purging, interlocks on doors/covers, and pressurization system evaluation as associated equipment.
• Testing and verification: Leakage tests, overpressure tests, purging and dilution tests, verification of minimum overpressure, type verification, routine tests and infallibility testing.
• Marking and instructions: Mandatory marking as pressurized equipment, warnings, indication of internal sources of release, static pressurization notes and user instructions.

Applications - who uses this standard

• Equipment manufacturers designing and certifying electrical equipment with pressurized enclosures (type "p")
• Certification and testing laboratories performing type and routine tests (leakage, overpressure, purging)
• Safety and design engineers in oil & gas, petrochemical, chemical processing, mining and grain-handling industries where explosive gas or dust atmospheres may occur
• End users/operators responsible for installation, maintenance and operating procedures for pressurized protected equipment

Related standards

• IEC 60079-0 - General requirements for electrical equipment in explosive atmospheres (supplemented/modified by IEC 60079-2)
• IEC 60079-13 - Pressurized rooms and analyser houses (see for pressurized rooms excluded from IEC 60079-2)
• IEC 60079-2 (2007) and IEC 61241-4 (2001) - previous editions replaced by this 2014 edition

This standard is essential for ensuring safe design, testing and deployment of pressurized enclosures used to protect electrical equipment in hazardous locations and for meeting regulatory and certification requirements.