IEC 60079-26:2021

Overview

IEC 60079-26:2021 is an international standard published by the International Electrotechnical Commission (IEC) that addresses the safety requirements for equipment used in explosive atmospheres. Specifically, this fourth edition focuses on equipment with separation elements or combined Equipment Protection Levels (EPLs), providing guidance for construction, testing, and marking. The standard applies to equipment mounted across boundaries that require different EPLs, such as between various gas hazardous zones, dust hazardous zones, or a combination of both.

This standard enhances safety by specifying requirements for both electrical and non-electrical equipment when mechanical energy could pose an ignition risk, mandating ignition hazard assessment in line with ISO 80079-36 where applicable. IEC 60079-26:2021 modifies and supplements the general requirements laid out in IEC 60079-0 and takes precedence where conflicts occur. Its scope extension also includes separation elements between all EPLs and covers combined types of protection.

Key Topics

• Separation Elements

  • Definition and role in maintaining safety between parts of equipment with differing EPLs
  • Requirements for partition walls including material specifications, thickness, and gas-tight conductor bushings
  • Consideration of natural ventilation for gas atmospheres to prevent hazardous accumulation

• Combined Equipment Protection Levels (EPLs)

  • Rules for combining two types of protection with EPL Gb to achieve the higher EPL Ga
  • Electrical connections and design principles ensuring effective separation and protection

• Construction and Testing

  • Type tests for standardized protection types and separation elements
  • Mechanical endurance testing, especially for partition walls subject to pressure and vibration, referring to IEC TS 60079-40
  • Requirements for temperature evaluation to guarantee safe operating conditions

• Marking and Documentation

  • Detailed marking instructions for equipment with combined protection levels or separation elements
  • Specification of EPL allocations and the thickness of separation elements in user instructions
  • Inclusion of warnings related to abrasive dust flow and other operational hazards

Applications

IEC 60079-26:2021 has practical applications across industries where explosive atmospheres are a risk, including:

• Oil and Gas Industry
  Equipment operating at boundaries of hazardous areas with different gas concentrations or dust presence, requiring stringent separation and protection

• Chemical and Petrochemical Plants
  Machinery and control devices mounted across zones with varied explosive gas and dust classifications, benefiting from combined EPL approaches

• Mining and Grain Processing
  Application to non-electrical and electrical equipment exposed to dust hazardous areas, ensuring partitions and separation elements effectively mitigate ignition risks

• Manufacturing Facilities
  Ensuring safety when equipment contains different protective systems or is subject to mechanical forces that may create ignition sources

Overall, compliance with IEC 60079-26:2021 facilitates the design and use of complex equipment assemblies that span multiple hazardous area classifications, improving worker safety and operational reliability.

Related Standards

IEC 60079-26:2021 is part of the comprehensive IEC 60079 series covering explosive atmospheres. Key related standards include:

• IEC 60079-0
  General requirements for electrical equipment in explosive atmospheres; foundational for all parts, but superseded by IEC 60079-26 where conflicts arise

• IEC 60079-36
  Addresses non-electrical equipment ignition hazard assessment, applicable when mechanical energy could cause ignition

• IEC TS 60079-40
  Provides guidance on endurance tests under vibrational and pressure stresses, referenced for testing separation elements

• ISO 80079-36
  International standard dealing with the construction and testing of non-electrical equipment for explosive atmospheres

Using IEC 60079-26 alongside these standards ensures full compliance with international safety expectations for equipment in hazardous environments, supporting best practices in explosion protection engineering.

Keywords: IEC 60079-26, explosive atmospheres, equipment protection level, separation elements, hazardous areas, electrical equipment, ignition hazard assessment, type testing, marking requirements, combined protection, EPL, gas hazardous area, dust hazardous area, IEC standards.