Hazardous Area Classification in Southern Africa

Walk into any refinery, chemical plant, gas processing facility, or underground mine in Southern Africa and you'll find equipment that was selected and installed based on how the surrounding space was classified. That process is Hazardous Area Classification, or HAC. If your site handles flammable gases, vapours, or combustible dust, you're legally required to do it.

What HAC is (and what it isn't)

HAC identifies the three-dimensional spaces where a flammable or explosive atmosphere could form in concentrations high enough to need ignition-source controls. The deliverable is a zone map: a documented, site-specific record of where explosive atmospheres can occur, how often, and for how long.

It's not a full risk assessment. Classification tells you where the hazard may exist. It doesn't evaluate what happens if ignition occurs, and it doesn't replace a process hazard analysis. But it's the foundation that everything else builds on. Equipment selection, installation standards, inspection intervals, maintenance procedures: all of these follow from the classification. Get it wrong and every decision downstream inherits the error.

The technical framework comes from two IEC standards: IEC 60079-10-1 for explosive gas atmospheres and IEC 60079-10-2 for explosive dust atmospheres. South Africa adopts these as SANS 60079-10-1 and SANS 60079-10-2 under SANS 10108, the primary standard for classification and equipment selection in the country. The 7th edition of SANS 10108 was published in February 2023.

The legal position in South Africa

HAC is a legal requirement, not a guideline.

Under the Occupational Health and Safety Act (Act 85 of 1993) and its Electrical Machinery Regulations (Clause 9.1), every employer must identify all hazardous locations and classify them in accordance with the applicable standards. You cannot operate electrical machinery where flammable gases, vapours, or dusts are present unless the location has been formally classified and the equipment matches.

Mining falls under separate authority: the Mine Health and Safety Act (Act 29 of 1996), enforced by the Department of Mineral Resources and Energy. This matters more than people realise. Underground coal mines deal with methane and suspended coal dust in ways that need a completely different engineering approach. Equipment certified for a surface petrochemical plant is not automatically suitable underground. Different regulators, different equipment groups, different rules. Don't treat them as interchangeable.

Non-compliance carries real consequences: fines, operational shutdown, and in serious cases, criminal liability for plant owners and responsible persons.

The zone system

Southern Africa uses the IEC zone system, not the North American division system. If you're working with equipment or drawings from the US, keep that in mind.

For gas, vapour, and mist hazards:

• Zone 0: Explosive atmosphere present continuously or for long periods (more than 1,000 hours per year)
• Zone 1: Likely to occur occasionally in normal operation (10 to 1,000 hours per year)
• Zone 2: Unlikely in normal operation, brief if it occurs (under 10 hours per year)

For combustible dust:

• Zone 20: Dust cloud present continuously or for long periods
• Zone 21: Dust cloud likely in normal operation occasionally
• Zone 22: Dust cloud unlikely in normal operation, brief if it occurs

Dust hazards are underestimated at far too many facilities. Grain storage, flour milling, woodworking, and certain chemical processing operations all generate combustible dust. A settled dust layer on a surface can ignite and feed a larger explosion. If your site handles powders or generates fine particulates, dust zone classification belongs in your HAC study, not as something you get to later.

How classification is done

A proper HAC study follows a structured process:

1. Identify the flammable substances on site using safety data sheets and process data.
2. Identify sources of release (continuous, normal operation, or abnormal/unplanned).
3. Assess ventilation and how far a flammable atmosphere could realistically extend.
4. Consider internal spaces of equipment where flammable material and air may mix.
5. Map zone boundaries in three dimensions.
6. Document and maintain the classification as a live record.

Classification must be carried out by a qualified engineer or a competent person with relevant knowledge of the process, the equipment, and the applicable standards. A team approach works better. Process, production, maintenance, and safety staff all hold information that a single engineer working alone simply won't have.

For complex or new plants, HAC should draw from a broader process hazard study such as a HAZOP or PHA, particularly where atmospheric dispersion modelling is needed.

Equipment selection and certification

Once you've established zones, electrical equipment in those areas must match the classification. Equipment is categorised by Equipment Protection Level (EPL):

• Zone 0 / Zone 20: EPL Ga or Da (intrinsic safety or encapsulation)
• Zone 1 / Zone 21: EPL Gb or Db (flameproof, increased safety, or intrinsic safety)
• Zone 2 / Zone 22: EPL Gc or Dc (non-sparking, restricted breathing, or energy-limited)

In South Africa, explosion-protected apparatus must hold a valid Inspection Authority (IA) certificate issued by an Approved Test Laboratory, such as MASC or Explolabs. This is a legal prerequisite for installation. IA certificates have a 10-year validity period, unlike ATEX or IECEx certificates which don't expire.

Imported equipment certified under ATEX or IECEx may be accepted without full re-testing, but it still needs to meet local certification requirements before installation. A European certificate on its own doesn't clear the equipment for use on a South African site.

All Ex equipment installations require Certificates of Compliance (COCs), which must be obtained and maintained.

Beyond South Africa

South Africa has the most developed regulatory and accreditation infrastructure for this work on the continent. MASC is the only IECEx-accredited certification body and test laboratory in Sub-Saharan Africa. The South African Flameproof Association (SAFA) provides liaison between industry, regulators, and international standards bodies.

Across the wider SADC region, the technical approach is broadly IEC-based. Similar zone language and equipment standards apply in Namibia, Botswana, Zimbabwe, and elsewhere. But the legal trigger, approval path, and enforcement body differ by country. SADCAS provides accreditation services across 13 SADC member states that don't have their own national bodies.

If your operations extend beyond South Africa, the technical framework translates reasonably well. But verify the specific regulatory requirements in each country. South African compliance does not automatically satisfy another jurisdiction's legal obligations.

Where it goes wrong

The same mistakes keep showing up, and most of them are avoidable:

• Treating the HAC drawing as a once-off deliverable instead of a live document that needs updating when anything changes.
• Classifying gas hazards but missing combustible dust hazards on the same site.
• Using equipment labels as the only check, without verifying that the EPL matches the zone and the specific gas or dust group.
• Applying surface-plant logic to mining environments.
• Not updating the classification after process modifications, layout changes, or new equipment.

A HAC study that was accurate five years ago may not reflect what's happening on the plant today. Every time ventilation changes, process conditions shift, or new equipment comes in, the classification should be reviewed. That's how a site that started with a solid study quietly accumulates risk.

What a well-managed site should have

• A site-specific HAC study, not a copied template from another facility.
• Zone drawings that are current, version-controlled, and reflect the actual plant layout.
• Equipment registers that cross-reference EPL requirements against what's installed.
• Valid IA certificates and COCs for all Ex equipment.
• A clear trigger for classification review within the management of change process.
• Qualified, competent people involved in any classification, selection, or inspection work.

All of this traces back to the zone map. If the classification is wrong or outdated, the rest falls apart.

This article is a general overview for engineering and operations teams. For site-specific hazardous area classification studies, zone drawings, or equipment selection guidance, consult a qualified engineer with experience in SANS 10108, IEC 60079, and relevant process industry standards.