# Hazardous Area Classification #safety #system-design #standard Hazardous area classification divides facilities into zones based on the probability and duration of explosive atmospheres, determining equipment requirements. ## Zone Classifications ### Zone 0 - Continuous explosive atmosphere - > 1000 hours/year - Requires highest level of protection - Rare in practice ### Zone 1 - Likely explosive atmosphere - 10-1000 hours/year - Requires high level of protection - Common in process areas ### Zone 2 - Unlikely explosive atmosphere - < 10 hours/year - Standard protection sufficient - Most common classification ## Classification Factors - Gas release frequency - Ventilation effectiveness - Gas dispersion characteristics - Process conditions - Historical data ## Equipment Requirements - Zone 0: Intrinsically safe or explosion-proof - Zone 1: Explosion-proof or increased safety - Zone 2: Standard equipment often acceptable - Must match gas group and temperature class ## Standards - IEC 60079 series - NFPA 70 (NEC) - ATEX directives - Local regulations ## Importance - Determines equipment selection - Affects installation costs - Ensures safety compliance - Guides detector placement ## Related Concepts - [[ATEX]] - [[Temperature Classes]] - [[Gas Detector Placement]]