Hazardous Area Classification (HAC)
We classify zones under IEC 60079 10 and NEC 500 506 with ignition source control for ATEX, IECEx and DSEAR
Hazardous Area
Classification (HAC)
Hazardous area classification defines the three dimensional zones around credible release points where electrical and non electrical equipment has to carry explosion protection. The IEC 60079 10 1 2020 third edition revision tightened the ventilation effectiveness analysis and clarified the treatment of the zone of negligible extent, which had long been a frequent cause of historical over classification. The North American equivalent uses the Class and Division scheme under NFPA 497 and 499, or the increasingly adopted Class and Zone hybrid under NFPA 70 Articles 505 and 506 for new facilities. The discipline carries more weight than it appears to, because incorrect classification drives both safety risk through the under classification of ignition credible volumes and cost through over classification, which adds 20 to 40 percent to electrical and instrumentation capex on top of a lifetime maintenance burden. Our team combines the IEC 60079 10 1 Annex C release rate calculations, CFD supported ventilation effectiveness for indoor and complex outdoor geometries, IEC 60079 10 2 for dust zones, IEC 80079 36 and 37 for non electrical ignition sources such as mechanical, friction and hot surface sources, and the EN 1127 1 ignition source inventory framework that ATEX inspections now expect.
Hazardous Area Classification (HAC) workflow
Identify all continuous, primary, and secondary grade release points from P&IDs, plot plans, equipment data, and process descriptions, record fluid, state, pressure, and temperature.
Apply IEC 60079 10 1 Annex C release rate equations per source, classify by grade and frequency, compute dispersion distance for zone extent determination.
Evaluate ventilation degree (high / medium / low) and availability (good / fair / poor) for each area, apply CFD or analytical methods for enclosed and complex geometries.
Determine Zone 0/1/2 (gas/vapour) and Zone 20/21/22 (dust) extents, apply Zone of Negligible Extent (NE) treatment per IEC 60079 10 1 2020 Ed.3 to prevent over classification.
Assign Equipment Protection Level (Ga/Gb/Gc or Da/Db/Dc), specify Ex protection concept per location, identify non electrical ignition sources per IEC 80079 36 and EN 1127 1.
Produce zone drawings (plan, sections, elevations), source of release register, EPL schedule, ATEX explosion protection document (EPD), and MOC trigger criteria.
Every deliverable from basis to handover
Complete Hazardous Area Classification (HAC) scope covering every calculation, drawing, specification, and construction support activity.
Outcomes of Hazardous Area Classification (HAC)
- We remove the coincidence of an ignition source with a hazardous atmosphere, which is the foundation of explosion prevention
- We close the under classification gap on naturally ventilated outdoor units
- We address the dust explosion ignition sources that gas focused classifications often miss
- We support realistic hot work and permit to work boundary decisions
- We use an IEC 60079 10 1 2020 third edition methodology that stands up under independent review
- We deliver the explosion protection document compliance that ATEX 2014 34 EU and DSEAR require
- We cover NEC Articles 500 to 506 and NFPA 497 and 499 for United States and Canadian installations
- We make the work hold firm through IECEx, FM and authority having jurisdiction examination
- We give you procurement grade equipment specifications with the correct protection level and Ex marking
- We right size the maintenance and proof test scope for your explosion protected equipment
- We set an MOC baseline that prevents inadvertent zone changing modifications
- We give you a realistic basis for portable equipment use and hot work permits
- We help you steer clear of the 20 to 40 percent electrical and instrumentation over specification common in legacy classifications
- We defer explosion protected equipment replacement through correct initial selection
- We reduce your lifetime explosion protected equipment maintenance burden
- We head off the cost of reclassification after an incident
Codes & standards we work to
Triggers that signal the need
Where Hazardous Area Classification (HAC) applies
Wellheads, separators, gas compression, FPSO topsides, produced water systems.
Distillation columns, reactors, heat exchangers, storage spheres, LPG handling.
Cryogenic exchangers, liquefaction trains, BOG compressors, storage and sendout.
Reactive systems, batch reactors, solvent handling, runaway reaction scenarios.
Boilers, HRSGs, steam headers, hydrogen systems, ammonia SCR units.
Sterile vessels, CIP/SIP, pressure fermenters, solvent recovery, spray dryers.
Tangible deliverables
- A HAC study report aligned to IEC 60079 10 third edition or the NEC equivalent
- A source of release register with grade and release rate calculations
- A ventilation assessment to Annex C
- Zone drawings covering the plot plan, sections and elevations
- An equipment protection level register per location
- An explosion protection technique selection schedule
- A non electrical ignition source register to IEC 80079 36
- A DSEAR and ATEX explosion protection document
- MOC trigger criteria and a revalidation schedule
Ready to start your project?
Speak with our team to scope an engagement tailored to your facility, regulatory context, and lifecycle stage.