{"id":258,"date":"2026-07-10T06:02:35","date_gmt":"2026-07-10T06:02:35","guid":{"rendered":"https:\/\/industrialelectricmotor.net\/?p=258"},"modified":"2026-07-10T06:02:35","modified_gmt":"2026-07-10T06:02:35","slug":"explosion-proof-motor-for-chemical-plant","status":"publish","type":"post","link":"https:\/\/industrialelectricmotor.net\/it\/explosion-proof-motor-for-chemical-plant\/","title":{"rendered":"Explosion-Proof Motor for Chemical Plant"},"content":{"rendered":"
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Korea Ever-Power \u00b7 YB2 Series \u00b7 Chemical Plant ATEX Drive Guide<\/span><\/p>\n

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Explosion-Proof Motor for Chemical Plant
\nPump and Fan: ATEX Selection Guide<\/span><\/h1>\n

Using a standard industrial motor in a chemical plant area where flammable vapour, gas, or mist may be present is a serious safety risk and a regulatory violation. The IEC\/ATEX zone classification system defines exactly which areas require explosion-proof motors, which gas group the motor must be certified for, and which temperature class limits the motor surface temperature to below the ignition point of the specific materials present. This guide explains the complete selection process for explosion-proof motors in chemical plant applications using the Korea Ever-Power YB2 Ex d series.<\/p>\n

Ex d IIB T4<\/span>
\nZone 1 and Zone 2<\/span>
\nIECEx \/ ATEX Certified<\/span>
\nIP55 Outdoor<\/span>
\n0.55\u2013200 kW<\/span><\/div>\n<\/div>\n<\/div>\n

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Ex d<\/div>\n
Flameproof enclosure<\/div>\n<\/div>\n
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IIB<\/div>\n
Gas group: ethylene equivalent<\/div>\n<\/div>\n
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T4<\/div>\n
Surface temp < 135\u00b0C<\/div>\n<\/div>\n
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Zone 1\/2<\/div>\n
IEC 60079-10 classification<\/div>\n<\/div>\n
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IP55<\/div>\n
Outdoor chemical plant rated<\/div>\n<\/div>\n<\/div>\n

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\"Explosion<\/p>\n
Korea Ever-Power YB2 series explosion-proof motor with Ex d IIB T4 certification \u2014 the flameproof enclosure (Ex d) contains any internal ignition within the motor housing so that it cannot propagate to a surrounding explosive atmosphere. Mandatory for all motors installed in IEC Zone 1 or Zone 2 hazardous area locations in chemical plants, refineries, and solvent handling facilities.<\/div>\n<\/div>\n

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Contents<\/div>\n
1. ATEX Zone 1 and Zone 2 Classification<\/a>
\n2. Gas Group Classification: IIA, IIB, IIC<\/a>
\n3. Temperature Class T4 Explained<\/a>
\n4. Ex d Flameproof vs Ex e Increased Safety<\/a>
\n5. YB2 Series Specifications<\/a>
\n6. Chemical Plant Applications<\/a>
\n7. Installation Rules for Hazardous Area Motors<\/a>
\n8. Frequently Asked Questions<\/a><\/div>\n<\/div>\n

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1. ATEX Zone 1 and Zone 2 Classification<\/h2>\n

IEC 60079-10-1 defines three zones for areas where explosive gas, vapour, or mist atmospheres may be present. The zone classification is based on the frequency and duration of the explosive atmosphere occurrence, not on the toxicity or quantity of the material. Every motor installed in a hazardous area must be certified for the zone in which it is installed.<\/p>\n

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Zone 0<\/div>\n
Explosive atmosphere continuously present<\/div>\n

Inside tanks, vessels, and enclosed spaces where explosive vapour-air mixtures are present continuously or for long periods (more than 1,000 hours per year). Standard motors including explosion-proof motors are NOT suitable for Zone 0. Zone 0 requires intrinsically safe (Ex ia) equipment specifically certified for this zone. Chemical plant equipment installed inside enclosed process vessels falls in Zone 0; motors driving agitators inside vessels are installed outside the vessel and are typically in Zone 1.<\/p>\n<\/div>\n

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Zone 1<\/div>\n
Explosive atmosphere likely under normal operation<\/div>\n

Areas around vent openings, pump seals, flanged connections, and process equipment where explosive vapour may be released during normal operation (10 to 1,000 hours per year). Pump rooms handling flammable solvents, areas within 0.5 m of open drainage systems, and areas around sample points on process pipework are typically classified as Zone 1. All motors in Zone 1 must be ATEX or IECEx certified Ex d, Ex e, or equivalent for Group II gases and the specific temperature class of the location.<\/p>\n<\/div>\n

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Zone 2<\/div>\n
Explosive atmosphere unlikely but possible<\/div>\n

Areas where explosive vapour is not expected during normal operation but may occur infrequently or for short periods (below 10 hours per year) \u2014 typically the area surrounding Zone 1 extending 1 to 3 m from Zone 1 boundaries. General outdoor areas of a chemical plant where flammable material is processed are typically Zone 2. Motors in Zone 2 must be ATEX\/IECEx certified Ex d or Ex e for Group II gases. A Zone 1 certified motor (Ex d IIB T4) is also suitable for Zone 2 installation.<\/p>\n<\/div>\n<\/div>\n

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Compliance requirement: using a standard non-explosion-proof motor in a Zone 1 or Zone 2 classified area is a violation of the ATEX Directive (EU 2014\/34\/EU), the IECEx scheme, and national safety legislation in most countries. It creates an ignition source in an area where explosive atmospheres may be present. The motor does not need to be running at the time of a spark event \u2014 internal arcing at contactor switch-on, brush sparking in wound-rotor motors, or static discharge from motor frames can all initiate an explosion in a Zone 1 or Zone 2 atmosphere. Only Ex-certified motors may be installed in classified zones.<\/p>\n<\/div>\n<\/div>\n

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2. Gas Group Classification: IIA, IIB, IIC<\/h2>\n

Group II gases are divided into three subgroups based on their maximum experimental safe gap (MESG) and minimum igniting current (MIC) ratio \u2014 both of which determine how likely a spark or hot surface inside the motor can propagate to an external explosive atmosphere through the flameproof enclosure joints. The motor must be certified for a gas group that covers the most hazardous gas present in the classified area.<\/p>\n

\n\n\n\n\n\n\n\n
Gas Group<\/th>\nTypical Gases and Solvents<\/th>\nMESG<\/th>\nMotor Certification Required<\/th>\nYB2 Suitable?<\/th>\n<\/tr>\n<\/thead>\n
IIA<\/td>\nPropane, butane, methane, acetone, ammonia, ethanol, toluene, xylene, methanol<\/td>\n> 0.9 mm<\/td>\nEx d IIA or higher<\/td>\nYes (IIB covers IIA)<\/td>\n<\/tr>\n
IIB<\/td>\nEthylene, diethyl ether, isopropyl alcohol, butadiene, vinyl chloride, styrene<\/td>\n0.5\u20130.9 mm<\/td>\nEx d IIB or higher<\/td>\nYes (YB2 is IIB)<\/td>\n<\/tr>\n
IIC<\/td>\nHydrogen, acetylene, carbon disulphide \u2014 highest explosion risk<\/td>\n< 0.5 mm<\/td>\nEx d IIC only<\/td>\nNo (requires IIC motor)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

The Korea Ever-Power YB2 series is certified Ex d IIB T4, meaning it is suitable for all Group IIA and IIB gases and vapours \u2014 covering the vast majority of chemical plant atmospheres including most organic solvents, petroleum fractions, and process gases. For areas where hydrogen (Group IIC) is the hazardous material \u2014 electrolysis plants, hydrogen storage, and some battery facilities \u2014 a Group IIC certified motor is required and the YB2 IIB is not adequate. Please confirm the specific gas group with the area classification document before specifying the motor.<\/p>\n<\/div>\n

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3. Temperature Class T4 Explained<\/h2>\n

The temperature class of an explosion-proof motor limits the maximum surface temperature of the motor enclosure to below the auto-ignition temperature of the hazardous atmosphere present. If the motor surface temperature exceeds the auto-ignition temperature of the surrounding explosive mixture, ignition can occur without any spark \u2014 hot surface ignition is as dangerous as electrical sparking in a hazardous area.<\/p>\n

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T1 \u2014 450\u00b0C max<\/div>\n
Motor surface must not exceed 450\u00b0C. Very few chemical plant solvents auto-ignite this high.<\/div>\n<\/div>\n
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T2 \u2014 300\u00b0C max<\/div>\n
Covers most methane and propane-group atmospheres. Standard for general chemical plant Zone 2.<\/div>\n<\/div>\n
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T3 \u2014 200\u00b0C max<\/div>\n
Required for petrol, kerosene, and petroleum ether. Common in oil and gas facilities.<\/div>\n<\/div>\n
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T4 \u2014 135\u00b0C max \u2605<\/div>\n
YB2 standard class. Covers ethylene, acetaldehyde, ethyl ether. Standard for most chemical plant areas.<\/div>\n<\/div>\n
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T5 \u2014 100\u00b0C max<\/div>\n
Required for carbon disulphide. Rarely specified for standard motors.<\/div>\n<\/div>\n
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T6 \u2014 85\u00b0C max<\/div>\n
Diethyl ether and some very low ignition temperature materials. Requires specially designed motor.<\/div>\n<\/div>\n<\/div>\n

The T4 temperature class of the YB2 (135\u00b0C surface limit) covers ethylene (auto-ignition 490\u00b0C), diethyl ether (160\u00b0C), acetaldehyde (175\u00b0C), and most common organic solvents encountered in chemical manufacturing. The area hazardous area classification document must specify the temperature class required for the specific atmosphere \u2014 never assume the default class is adequate without checking the auto-ignition temperature of the most flammable material present.<\/p>\n<\/div>\n

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4. Ex d Flameproof vs Ex e Increased Safety<\/h2>\n
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Ex d \u2014 Flameproof (Explosion-Proof)<\/div>\n

Ex d motors are designed to contain any internal explosion within the motor housing and prevent propagation to the external atmosphere. The motor is not spark-free internally \u2014 instead, the housing is built to withstand the internal explosion pressure (typically 10 to 15 bar) and all external joints are designed with precise gap dimensions (MESG) that cool any escaping hot gas below the ignition temperature of the surrounding atmosphere before it exits. Ex d motors are suitable for Zone 1 and Zone 2.<\/p>\n

Korea Ever-Power YB2: Ex d IIB T4. Use for Zone 1 and Zone 2 with IIA and IIB gas groups.<\/div>\n<\/div>\n
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Ex e \u2014 Increased Safety<\/div>\n

Ex e motors prevent the occurrence of sparks, arcs, or hot surfaces under normal operation and under specified overload conditions, by applying enhanced construction standards to eliminate the internal ignition sources that Ex d merely contains. Ex e motors have no brush contacts, no commutator, and use enhanced winding insulation and temperature monitoring. Ex e squirrel-cage motors are often preferred in Zone 2 because their open enclosure (compared to the sealed heavy cast iron Ex d enclosure) provides better natural ventilation and cooling, improving efficiency and reducing weight. Ex e motors require mandatory winding temperature monitoring (PTC thermistors) connected to a certified protection relay.<\/p>\n

Ex e: suitable for Zone 2 only. Cannot be used in Zone 1 without additional Ex d enclosure.<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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5. Korea Ever-Power YB2 Series Specifications<\/h2>\n
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The Korea Ever-Power YB2 series is a three-phase squirrel-cage induction motor certified to Ex d IIB T4 under both the ATEX Directive and the IECEx scheme. It is suitable for installation in Zone 1 and Zone 2 hazardous areas where the explosive atmosphere is classified as Group IIA or IIB (including most organic solvents, petroleum fractions, and chemical plant gases other than hydrogen and acetylene). The full YB2 range is available in the explosion-proof motors product section<\/a>.<\/p>\n

The YB2 is built on the same IEC 72-1 metric frame platform as the standard Y2 series, allowing it to replace a standard Y2 motor in an existing installation with no modification to the motor baseplate, coupling, or conduit entry positions. The heavy-duty cast iron enclosure provides IP55 protection for outdoor chemical plant installation exposed to rain and hose-down cleaning. The terminal box is sealed with an Ex d certified cable gland position for use with armoured cable or conduit systems in the hazardous area.<\/p>\n<\/div>\n

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YB2 Series Key Specifications<\/div>\n\n\n\n\n\n\n\n\n\n\n\n
Certification<\/td>\nATEX + IECEx: Ex d IIB T4<\/td>\n<\/tr>\n
Zone suitability<\/td>\nZone 1 and Zone 2<\/td>\n<\/tr>\n
Gas group<\/td>\nIIA and IIB (not IIC)<\/td>\n<\/tr>\n
Surface temp limit<\/td>\nT4 = 135\u00b0C maximum<\/td>\n<\/tr>\n
Power range<\/td>\n0.55\u2013200 kW<\/td>\n<\/tr>\n
Enclosure<\/td>\nIP55, cast iron frame<\/td>\n<\/tr>\n
Voltage \/ frequency<\/td>\n380 V 50 Hz standard<\/td>\n<\/tr>\n
Frame<\/td>\nIEC 72-1 (same as Y2)<\/td>\n<\/tr>\n
Insulation<\/td>\nClass F<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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6. Chemical Plant Applications<\/h2>\n\n\n\n
\"Explosion<\/p>\n
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Solvent and Chemical Transfer Pumps<\/div>\n

Centrifugal and gear pumps handling flammable solvents \u2014 ethanol, toluene, xylene, acetone, methanol, methylene chloride \u2014 are installed in Zone 1 around the pump seal and flanges. YB2 Ex d IIB T4 motors in 0.75 to 22 kW, 2-pole or 4-pole, provide the certified hazardous area protection required. The motor is direct-coupled to the pump via flexible coupling on a common baseplate outside the Zone 0 interior of the vessel or tank. IP55 for outdoor chemical plant installation; Ex d cable glands mandatory on all terminal box entries.<\/p>\n<\/div>\n<\/td>\n

\"Explosion<\/p>\n
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Ventilation and Exhaust Fan Drives<\/div>\n

Chemical plant ventilation fans and fume extraction systems handling flammable vapour-laden air are installed in Zone 1 at the duct connection and Zone 2 in the surrounding area. YB2 Ex d IIB T4 motors in 1.5 to 30 kW drive the fans through a V-belt or direct coupling. For paint spray booths, coating lines, and solvent recovery units where exhaust fans handle solvent-laden air at concentrations that may approach the lower explosive limit (LEL), Ex d certification to the appropriate gas group is mandatory regardless of the ambient zone classification of the surrounding area.<\/p>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

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Reactor Agitator Drive<\/div>\n

External agitator motors driving stirrers inside chemical reactors through mechanical seals are in Zone 1. YB2 4-pole or 6-pole in 1.5 to 22 kW, typically paired with NMRV worm gearbox for slow agitation speed (10 to 60 rpm). Both motor and gearbox must be in Ex d enclosures.<\/p>\n<\/div>\n

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Compressor and Blower Drive<\/div>\n

Gas compressors and process air blowers in chemical plant areas handling flammable process gas require YB2 Ex d IIB T4 motors in 5.5 to 200 kW. The motor must be grounded to the compressor skid frame with an Earth bonding conductor sized to carry the full motor fault current for a time sufficient to operate the fuse or circuit breaker.<\/p>\n<\/div>\n

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Tank Farm Loading Pump<\/div>\n

Liquid product loading pumps at tank farm bays handling petroleum products (petrol, diesel, jet fuel) are Zone 2 during normal operation and Zone 1 during loading. YB2 Ex d IIB T4 provides Zone 1 certification applicable to both normal and loading conditions without requiring two different motor specifications.<\/p>\n<\/div>\n

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Wastewater and Effluent Pump<\/div>\n

Chemical plant effluent pumps handling solvent-contaminated wastewater may be in Zone 2 if solvent concentrations above 25% LEL are possible. Where classified as Zone 2, YB2 Ex d IIB T4 provides the required certification with IP55 for outdoor sump and pit installation.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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7. Installation Rules for Hazardous Area Motors<\/h2>\n
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Cable Entry: Ex d Certified Glands Only<\/div>\n

All cable entries into a YB2 terminal box must use Ex d certified cable glands of the correct type and diameter for the cable used. Standard IP68 or waterproof cable glands are not sufficient for Ex d applications \u2014 the gland must be specifically certified for use with Ex d enclosures and must be installed to maintain the Ex d integrity of the terminal box as defined in IEC 60079-0.<\/p>\n<\/div>\n

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Earthing: Dedicated Earth Bonding<\/div>\n

The YB2 motor frame must be connected to the plant earth bonding network with a dedicated earthing conductor connected to the external earth bonding bolt provided on the motor frame. Earth continuity must be verified as part of the pre-commissioning inspection and recorded in the area electrical inspection records.<\/p>\n<\/div>\n

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Temperature Monitoring: PTC Required for Extended Overload<\/div>\n

In Zone 1 installations where the motor may experience extended overload conditions (such as pump blockage or cavitation), PTC winding thermistors should be installed and connected to a certified thermistor relay. An overloaded Ex d motor may develop surface temperatures above the T4 limit of 135\u00b0C before the motor overload relay trips, creating an ignition hazard even with a correctly sized motor.<\/p>\n<\/div>\n

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Inspection: Area Electrical Inspection Schedule<\/div>\n

Hazardous area electrical equipment (including Ex d motors) must be periodically inspected per IEC 60079-17 to verify that the Ex d integrity is maintained \u2014 that all fasteners are present, terminal box lid is correctly fitted, cable glands are tight, and the motor frame is not corroded. In Zone 1 areas, close inspection is typically required at least every 3 years; in Zone 2 every 5 years.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

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\"Korea<\/p>\n

Precision Enclosure Machining<\/div>\n<\/div>\n
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\"Korea<\/p>\n

Ex d Testing<\/div>\n<\/div>\n
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\"Korea<\/p>\n

ATEX and IECEx<\/div>\n<\/div>\n
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\"Korea<\/p>\n

Global Export<\/div>\n<\/div>\n<\/div>\n

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8. Frequently Asked Questions<\/h2>\n
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Can I use a VFD to control a YB2 explosion-proof motor?<\/div>\n<\/div>\n
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Yes, but the VFD itself must be installed outside the hazardous area (in a safe area control room or in an Ex d or Ex p VFD enclosure within the hazardous area) and must be specifically certified for use with Ex d motors. When driving an Ex d motor with a VFD, the VFD output waveform (PWM) can cause the motor surface temperature to rise above the T4 limit of 135\u00b0C if the motor runs continuously at low speed with full load torque \u2014 the standard IC411 cooling on the YB2 is not adequate for low-speed VFD operation. For VFD-controlled hazardous area drives, Korea Ever-Power recommends specifying a YB2 motor with the IC416 forced cooling option (separate blower motor on the YB2) or using an Ex-certified dV\/dt output filter to reduce harmonic heating in the motor winding. Consult our technical team for a full Ex motor VFD application review.<\/p>\n<\/div>\n<\/div>\n

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Is the YB2 suitable for a Zone 2 area where the atmosphere is only occasionally flammable?<\/div>\n<\/div>\n
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Yes. The YB2 is certified for Zone 1, which includes Zone 2 \u2014 a Zone 1 certified motor is always suitable for the less demanding Zone 2 environment. However, for Zone 2 only locations, an Ex e (increased safety) motor is also an acceptable alternative to Ex d, and may be preferred for energy efficiency and weight reasons as Ex e motors use a lighter open construction rather than the heavy cast iron Ex d enclosure. For Zone 2 areas where the customer wants the simplest specification and the same motor for all zones in a plant, the YB2 Ex d IIB T4 is a reliable single-specification solution that covers all Zone 1 and Zone 2 requirements with a single motor type.<\/p>\n<\/div>\n<\/div>\n

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What documentation must I have on file for an explosion-proof motor installation?<\/div>\n<\/div>\n
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For each YB2 motor installed in a classified area, the installation file should contain: the ATEX\/IECEx certificate of conformity (confirming Ex d IIB T4 classification and the notified body certificate number); the hazardous area classification drawing showing the zone designation of the installation location; the area electrical equipment register entry for this motor; the initial inspection record confirming cable glands, earthing, and Ex integrity at installation; the commissioning test record; and subsequent periodic inspection records. In the EU, this documentation is required to demonstrate compliance with the ATEX User Directive (1999\/92\/EC). Korea Ever-Power supplies the ATEX\/IECEx certificate with each YB2 motor as standard documentation.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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Korea Ever-Power \u00b7 YB2 Series \u00b7 ATEX IECEx Ex d IIB T4<\/div>\n

Need Explosion-Proof Motors for Your Chemical Plant?<\/h2>\n

Korea Ever-Power YB2 series: ATEX + IECEx Ex d IIB T4, IP55, 0.55\u2013200 kW. Certified for Zone 1 and Zone 2. Supplied with full ATEX certification documentation.<\/p>\n

View YB2 Explosion-Proof Range<\/a><\/p>\n<\/div>\n<\/div>\n

Edited by Cxm<\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"

Korea Ever-Power \u00b7 YB2 Series \u00b7 Chemical Plant ATEX Drive Guide Explosion-Proof Motor for Chemical Plant Pump and Fan: ATEX Selection Guide Using a standard industrial motor in a chemical plant area where flammable vapour, gas, or mist may be present is a serious safety risk and a regulatory violation. The IEC\/ATEX zone classification system […]<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[28],"tags":[],"class_list":["post-258","post","type-post","status-publish","format-standard","hentry","category-industrial-electric-motor"],"_links":{"self":[{"href":"https:\/\/industrialelectricmotor.net\/it\/wp-json\/wp\/v2\/posts\/258","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/industrialelectricmotor.net\/it\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/industrialelectricmotor.net\/it\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/industrialelectricmotor.net\/it\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/industrialelectricmotor.net\/it\/wp-json\/wp\/v2\/comments?post=258"}],"version-history":[{"count":1,"href":"https:\/\/industrialelectricmotor.net\/it\/wp-json\/wp\/v2\/posts\/258\/revisions"}],"predecessor-version":[{"id":260,"href":"https:\/\/industrialelectricmotor.net\/it\/wp-json\/wp\/v2\/posts\/258\/revisions\/260"}],"wp:attachment":[{"href":"https:\/\/industrialelectricmotor.net\/it\/wp-json\/wp\/v2\/media?parent=258"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/industrialelectricmotor.net\/it\/wp-json\/wp\/v2\/categories?post=258"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/industrialelectricmotor.net\/it\/wp-json\/wp\/v2\/tags?post=258"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}