{"id":1617,"date":"2026-05-06T03:02:36","date_gmt":"2026-05-06T03:02:36","guid":{"rendered":"https:\/\/wormreducers.xyz\/?p=1617"},"modified":"2026-05-06T03:02:36","modified_gmt":"2026-05-06T03:02:36","slug":"atex-and-iecex-worm-gearbox-hazardous-area-certification-specification","status":"publish","type":"post","link":"https:\/\/wormreducers.xyz\/fr\/atex-and-iecex-worm-gearbox-hazardous-area-certification-specification\/","title":{"rendered":"R\u00e9ducteur \u00e0 vis sans fin ATEX et IECEx\u00a0: Sp\u00e9cifications de certification pour zones dangereuses"},"content":{"rendered":"
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\u26a0 EX-RATED PROCUREMENT<\/div>\n

R\u00e9ducteur \u00e0 vis sans fin ATEX et IECEx\u00a0: Sp\u00e9cifications de certification pour zones dangereuses<\/h1>\n

Zone classification, equipment category coding (II 2G T4), T-class surface temperature limits, ignition source elimination, certification documentation chain and IECEx\/MSHA equivalence.<\/p>\n

Request an Ex-Rated Quote \u2192<\/a><\/p>\n<\/div>\n<\/div>\n

Hazardous-area worm gearbox specification sits at the intersection of mechanical engineering and explosion-prevention regulation. EU plants apply ATEX directive 2014\/34\/EU; IEC member states apply the IECEx scheme aligned with IEC 60079; US mining applies MSHA permissibility under 30 CFR Part 18 and Part 36. The three frameworks share the same physics \u2014 ignition-source elimination through controlled surface temperature, contained mechanical contact, and verified manufacturing quality \u2014 but differ in documentation, marking, and notified-body involvement. The article below decodes zone classification, the equipment category code (II 2G T4 etc.), T-class surface temperature limits applicable to a worm gearbox, the four ignition-source mechanisms specific to worm-architecture drives, and the certification documentation chain required for plant approval.<\/p>\n

\"Types<\/p>\n

ATEX vs IECEx vs MSHA \u2014 Three Regulatory Frameworks<\/h2>\n

Three major regulatory frameworks govern hazardous-area worm gearbox supply across global markets. Each enforces the same underlying physics but through different administrative routes.<\/p>\n

\n\n\n\n\n\n\n\n
Framework<\/th>\nJurisdiction<\/th>\nKey Standard<\/th>\nMarking<\/th>\n<\/tr>\n<\/thead>\n
ATEX<\/td>\nEU + EEA<\/td>\nDirective 2014\/34\/EU<\/td>\nCE Ex symbol + category code<\/td>\n<\/tr>\n
IECEx<\/td>\nIEC member states (mutual recognition)<\/td>\nIEC 60079 series<\/td>\nIECEx certificate number<\/td>\n<\/tr>\n
MSHA<\/td>\nUS underground mining<\/td>\n30 CFR Part 18 \/ Part 36<\/td>\nMSHA approval number<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

For Korean-manufactured worm gearbox supplied into EU markets, ATEX is the operative scheme. For supply into Australia, India, Brazil, Korea, Japan and most of Southeast Asia, IECEx is typical. For US underground coal mines, MSHA applies in addition. Multi-market supply often carries dual ATEX + IECEx certification \u2014 IECEx test data accelerates ATEX type examination via mutual technical recognition, but separate ATEX notified-body involvement remains mandatory. Surface industries in the US apply NEC\/CEC area classification rather than MSHA; the equivalent worm gearbox certification path here is UL\/CSA Class I Division 1 or 2.<\/p>\n

Zone Classification \u2014 Gas Atmospheres and Dust Atmospheres<\/h2>\n

Hazardous areas divide into zones by likelihood of explosive atmosphere presence. Gas zones (G) and dust zones (D) are independently classified; an area can be both Zone 1 gas and Zone 22 dust, in which case the worm gearbox specification must satisfy both atmospheres simultaneously.<\/p>\n

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GAS ATMOSPHERES<\/p>\n<\/div>\n

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Zone 0:<\/strong> Explosive atmosphere continuously, for long periods, or frequently.<\/p>\n

Zone 1:<\/strong> Explosive atmosphere likely to occur in normal operation.<\/p>\n

Zone 2:<\/strong> Explosive atmosphere unlikely; if present, only briefly.<\/p>\n<\/div>\n<\/div>\n

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DUST ATMOSPHERES<\/p>\n<\/div>\n

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Zone 20:<\/strong> Combustible dust cloud continuously or frequently.<\/p>\n

Zone 21:<\/strong> Dust cloud likely in normal operation.<\/p>\n

Zone 22:<\/strong> Dust cloud unlikely; if present, only briefly.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

Drive installations rarely sit in Zone 0 (interior of fuel tanks, distillation column trays) \u2014 these zones use intrinsically safe instrumentation rather than mechanical drives. Zone 1 and Zone 2 cover most demand: Zone 1 includes flammable solvent storage rooms, paint booth interiors, sewage pump pits with methane potential. Zone 2 includes battery rooms, fuel transfer pump skids, and well-ventilated solvent loading areas. For dust atmospheres, Zone 21 includes silo discharge areas and mill enclosures; Zone 22 includes packaging halls handling fine powders.<\/p>\n

Equipment Category Code \u2014 Decoding II 2G T4<\/h2>\n

An ATEX-marked unit carries a category code that maps the unit to its acceptable installation zone. The code structure breaks into four positions:<\/p>\n

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II 2G T4<\/p>\n

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II<\/p>\n

Equipment group: I = mining (underground), II = surface industries.<\/p>\n<\/div>\n

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2<\/p>\n

Category: 1 = Zone 0\/20, 2 = Zone 1\/21, 3 = Zone 2\/22.<\/p>\n<\/div>\n

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G<\/p>\n

Atmosphere: G = gas, D = dust. Both shown as separate codes when applicable.<\/p>\n<\/div>\n

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T4<\/p>\n

T-class: T1-T6 maximum surface temperature rating (see next section).<\/p>\n<\/div>\n<\/div>\n<\/div>\n

A worm gearbox marked II 2G T4 is therefore: surface industry equipment, suitable for Zone 1 gas atmospheres, with maximum surface temperature 135 \u00b0C. The same unit cannot be installed in Zone 0 (requires II 1G), and is conservative if installed in Zone 2 (where II 3G would suffice). Buying a category higher than the installation zone requires is wasteful capital; buying lower than required causes plant approval failure.<\/p>\n

\"Worm<\/p>\n

T-Class Surface Temperature Limits \u2014 Six Steps<\/h2>\n

T-class limits map maximum equipment surface temperature against gas auto-ignition thresholds. Most flammable gases auto-ignite somewhere between 200 \u00b0C and 450 \u00b0C; specifying the gearbox T-class to stay below this auto-ignition value is the core ignition-source elimination requirement.<\/p>\n

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T1<\/p>\n<\/div>\n

\u2264 450 \u00b0C max surface<\/span>
\nMethane, ammonia, hydrogen<\/span><\/div>\n<\/div>\n
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T2<\/p>\n<\/div>\n

\u2264 300 \u00b0C max surface<\/span>
\nAcetylene, ethyl alcohol, propane<\/span><\/div>\n<\/div>\n
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T3<\/p>\n<\/div>\n

\u2264 200 \u00b0C max surface<\/span>
\nPetrol, diesel, hexane, naphtha<\/span><\/div>\n<\/div>\n
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T4<\/p>\n<\/div>\n

\u2264 135 \u00b0C max surface \u2014 most common worm gearbox spec<\/span>
\nEthyl ether, acetaldehyde<\/span><\/div>\n<\/div>\n
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T5<\/p>\n<\/div>\n

\u2264 100 \u00b0C max surface<\/span>
\nCarbon disulfide<\/span><\/div>\n<\/div>\n
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T6<\/p>\n<\/div>\n

\u2264 85 \u00b0C max surface<\/span>
\nSpecialty (rare in industry)<\/span><\/div>\n<\/div>\n<\/div>\n

For most surface industrial worm gearbox installations, T4 (135 \u00b0C) is the practical specification. Standard worm gearbox oil-bath operation runs 65-85 \u00b0C steady-state under nominal load \u2014 comfortably below T4. Under heavy continuous duty or high ambient (40+ \u00b0C), oil-bath temperature can climb toward 105-115 \u00b0C, which encroaches on the T4 limit and may require sizing up one frame or specifying forced cooling to maintain margin.<\/p>\n

Four Mechanical Ignition Sources Specific to Worm-Architecture<\/h2>\n

An ATEX-rated worm gearbox eliminates four ignition-source mechanisms that generic industrial designs leave open. Each is addressed by specific material, design or sealing choices.<\/p>\n

\"worm<\/p>\n

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\u26a0 IGNITION 01<\/p>\n

Hot mesh and bearing surfaces<\/p>\n

Worm-wheel mesh sliding-contact friction generates 60-85% of total gearbox heat. Limit by oversizing frame, synthetic PAG lubricant with high VI, and active thermal monitoring.<\/p>\n<\/div>\n

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\u26a0 IGNITION 02<\/p>\n

Mechanical sparks from contact<\/p>\n

Steel-on-steel impact (cover bolt-down, output shaft against guard) can produce sparks. Eliminate by non-sparking materials (bronze, beryllium copper) on impact-prone contact points.<\/p>\n<\/div>\n

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\u26a0 IGNITION 03<\/p>\n

Static electricity discharge<\/p>\n

Painted housings can accumulate static charge. ATEX-rated housings use conductive coatings (volume resistivity < 1 G\u03a9) and explicit equipotential bonding to plant ground.<\/p>\n<\/div>\n

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\u26a0 IGNITION 04<\/p>\n

Self-heating from oil decomposition<\/p>\n

Mineral oil oxidation past 90 \u00b0C generates exothermic decomposition pathways. Synthetic PAG resists oxidation 4-6\u00d7 longer; ATEX worm gearbox specifications mandate synthetic fill at T4 and below.<\/p>\n<\/div>\n<\/div>\n

Certification Documentation Chain<\/h2>\n

A delivered ATEX-rated worm gearbox carries five documents that constitute the audit-ready compliance package. Plant approval engineers and notified body inspectors review these before commissioning sign-off:<\/p>\n