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Zone Classification · EX Academy Knowledge Base

Zone 20 — Combustible Dust Atmospheres (Continuously Present)

EX Academy Knowledge Base · IEC 60079 · CompEx Preparation · 2025

This article covers Zone 20 — Combustible Dust Atmospheres (Continuously Present). Zone 20 is the most hazardous dust zone where combustible dust clouds are continuously present. This guide explains Zone 20 equipment requirements, EPL Da, and typical Zone 20 locations in industry.

Key Requirements

This zone classification is defined in IEC 60079-10 and governs equipment selection for all electrical installations in this area. The zone determines the minimum EPL required for any equipment installed.

Practice in the Simulator

EX Academy's inspection simulations and selection scenarios include questions covering this zone classification. Practise applying the requirements to real equipment selection and inspection decisions.

Equipment Selection

Always verify zone classification drawings before selecting or installing equipment. Contact the site area classification authority if zone boundaries are unclear. Never assume a zone without documentary evidence from the official area classification drawing.

Put This Into Practice

Reading about it is one thing. EX Academy puts you in the scenario — interactive inspection simulations, equipment selection decisions, and 1,185+ practice questions referenced to IEC 60079.

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