The ATEX-zone challenge
An ATEX zone (ATmosphère EXplosive) is a space where an explosive atmosphere may form — flammable gases, vapours, dusts. In refineries, petrochemical plants and mining sites, ATEX classification covers most processes. In these zones, welding, grinding and any hot work are forbidden without a complex waiver (production shutdown, purge, inerting, gas certification).
Cold-curing composites (epoxy, polymers) emit no spark and no heat input. They allow repairs in ATEX zones with no waiver, no shutdown, no inerting. This is why they became the reference method for emergency refinery repairs.
ATEX repair methodology
A composite repair in an ATEX zone follows a strict methodology, aligned with the site's permit-to-work and HSE risk analysis:
- Permit-to-work: issued for « cold work », less restrictive than hot work
- Gas analysis: H₂S, LEL, O₂ detector before intervention (mandatory in confined space)
- Electrical isolation of nearby rotating equipment
- Mechanical prep (wire brush, pneumatic grinder) if blasting is impossible
- Composite application at ambient temperature, spark-free
- Tightness check post-cure (holiday test, visual inspection)
Collective protective equipment
Even without hot work, an ATEX-zone intervention requires adapted PPE and collective protections: anti-static suit (to avoid electrostatic discharges), spark-resistant tools (bronze, beryllium), mechanical ventilation (to prevent vapour accumulation), portable gas detector, and radio communication with the control room.
Limits and precautions
Composite repairs in ATEX zones have limits: they do not suit very high pressures (mandatory composite thickness calculation), nor service temperatures > 120-150 °C. Cleaning solvents must be ATEX-compatible (high flash point). Finally, final mechanical strength is reached only after full cure — plan a delay before reloading.
Conclusion
Composite repair in ATEX zones is a game-changer for petrochemical and mining sites: it enables fast, safe interventions without the constraints of hot work. HSE methodology rigour remains non-negotiable.
Hicham M, P Eng, PMP
Engineer and project manager (PMP) at Induscoat Canada. Over 16 years of experience in industrial coatings, composite repairs and wear protection on mining, energy and petrochemical sites in Canada and internationally.