24542 Basics of Atex

8/11/2019 24542 Basics of Atex

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Basics of Atex


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ContentsBasics of ATEX............................................................................................4

Comparison of IEC with EN standards..............................................5

Common principles of explosion and risk management..........6

Explosion groups..................................................................................... 7

Risk management....................................................................................8Ex area inspections and maintenance..............................................9

Basics: Classification of zones............................................................10

Equipment categories..........................................................................11

Equipment protection levels (EPL) for Ex equipm ent..............12

Temperature............................................................................................14

Types of protection...............................................................................16

Marking.....................................................................................................18

North American equipment certification

Requirements for hazardous locations..........................................19

The road to conformity for ATEX......................................................22

Selecting cable gland...........................................................................23


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5

Basics of ATEX

he ATEX Directive 99/92/EC classifies explo-

ve atmospheres into area classes. This clas-fication is applied to atmospheres where aombination of dusts, aerosols, vapors, gases,nd air may form an explosive mixture. Areashere this standard must be applied are, for

xample, oil refineries, paint shops, biogasower plants and peat processing plants. De-gn aims to classify areas into groups and areaasses, each of which has its own rules for ap-ying protection methods and precautions.

his is referred to as drawing up an explosionrotection document, prepared according torective 99/92/EY. Area classification aims tove lives using cost-efficient and reasonable

sk management principles.

rective 94/9/EC refers to equipment and pro-ction systems intended to be used in explo-

sive atmospheres. Generally this Directive is re-

ferred to as: the ATEX Equipment Directive. Itspurpose is to create a harmonized set of normsto unify the legislation of the member states.

This Directive is applied to all equipment andcomponents intended to be used in areaswhere explosive liquids, gases, or dusts arepresent. For example, the following equip-ment is classified as primary ATEX equipment:electrical and mechanical equipment, protec-tion systems, safety and control systems, andthe components of equipment protection sys-tems. The Directive does not apply to medi-cal equipment, household gas equipment orfacilities for storing explosives. Internationalstandard IEC 60079-0 and the CENELEC EN60079-0 standard contain more detailedspecifications for equipment and require-

ments. The common goal is to provide a set of

instructions to ensure that devices sold meetessential safety requirements.

The main principle in making the safety clas-sification is to prevent the formation of anEx atmosphere. This is done by eliminatingsources of ignition and by minimizing theconsequences of possible explosions (94/9/EC). The most important thing is to take allsafety requirements into account. These mayinclude all sources of ignition, faults, and po-tentially incorrect uses. The safety specifica-tions also include safety, maintenance, andprotection instructions and related markings.The previous guidelines primarily containedinstructions on managing the current situ-ation. Future technical developments mustalso be taken into account.

ATEX, Appareils destins tre utiliss en ATmosphres EXplosi-

bles, refers to possible hazardous environment where an explo-

sive mixture of air and explosive material may be present in a

room, a part of a room or a restricted indoor or outdoor space.

Comparison of IEC with EN standards

The table below compares the IEC standard to corresponding CENELEC standards. Thepurpose of the table is to help in the comparison of national requirements with internationalones. Mainly these standards cover all general regulations for determining the classificationsof groups, design parameters and regulation of systems, and also installation and operation,all in the areas where explosive gases, vapors and dust are present.

Title

Contents

Document

IEC

Document

CENELEC

Date

YearExplosive atmospheres -

Part 0: Equipment - General requirementsIEC 60079-0 EN 60079-0 2009

Explosive atmospheres -

Part 1: Equipment protection by flameproof e nclosures dIEC 60079-1 EN 60079-1 2007


Part 2: Equipment protection by pres surized enclosure pIEC 60079-2 EN 60079-2 2007

Electrical apparatus for explosive gas atmospheres -

Part 4: Method of test for ignition temperatureI EC 6 00 79- 4 - -


Part 5: Equipment protection by powder filling qIEC 60079-5 EN 60079-5 2007

Explosive atmospheres -Part 6: Equipment protection by oil immersion o

IEC 60079-6 EN 60079-6 2007


Part 7: Equipment protection by i ncreased safety eIEC 60079-7 EN 60079-7 2007

Electrical apparatus for explosive gas atmospheres

Part 10: Classification of hazardous areasI EC 60 07 9- 10 E N 6 00 79 -1 0 2 00 3


Part 11: Equipment protection by intrinsic safety iI EC 60 07 9- 11 E N 6 00 79 -1 1 2 00 7


Part 14: Electrical installation design, selection, and erectionI EC 60 07 9- 14 E N 6 00 79 -1 4 2 00 3


Part 15: Construction, test and marking of

type of protection nelectrical apparatus

I EC 60 07 9- 15 E N 6 00 79 -1 5 2 00 5


Part 17: Electrical installation inspection and maintenanceI EC 60 07 9- 17 E N 6 00 79 -1 7 2 00 7

Electricalapparatusforexplosivegasatmospheres- Part18:Construction,test-

ing,andmarkingof typeofprotectionencapsulationmelectricalapparatusI EC 60 07 9- 18 E N 6 00 79 -1 8 2 00 6


Part 25: Intrinsically safe systemsI EC 60 07 9- 25 E N 6 00 79 -2 5 2 00 6


Part 26: Equipment with equipment protection level (EPL) Ga I EC 60 07 9- 26 E N 6 00 79 -2 6 2 00 7

Explosive atmospheres - Part 28: Protection of equipment and

transmission systems using optical radiationI EC 60 07 9- 28 E N 6 00 79 -2 8 2 00 7

Explosive atmospheres - Part 30-1: Electrical resistancetrace heating - General and testing requirements

IEC 60079-30-1 EN 60079-30-1 2007

Explosive Atmospheres -

Part 31: Equipment dust i gnition protection by enclosure tDI EC 600 79- 31 E N 6 00 79- 31 -

De grees of protection provided by enclosures (IP Code) IEC 60529 EN 60529 1993


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Ignitionsource

Flammablematerial

Oxygen

Common principles of explosion and

risk management

n explosion is a sudden increase in volumend a release of energy in a harmful manner.sually it involves the generation of high tem-eratures and the release of gases. An explo-on causes pressure waves. Explosions areategorized as deflagrations if these wavese subsonic and detonations if they are su-

ersonic (shock waves). A third type is a ther-al explosion, which occurs with the rapid

onversion of a highly exothermic reactionccompanied by a temperature rise. The dis-strous property of an explosion comes withrise in pressure and often with a high dosef heat radiation from the fireball, both oc-urring in a very short period of time. In ATEXeas, causes of explosion must be eliminated

r minimized.

o generate the sudden chemical reaction ofn oxygen and flammable substance com-ound, the mixture must be in an explosionnge to release a high-energy explosion.ammable substances normally occur in therm of a dust, mist, gas, or vapor. Normally an

xplosion occurs only if the three main factorsact in a convenient mixture.

Flammable materialOxygenIgnition source

ammable materials can be flammable gases,ammable liquids, and flammable solids. Ofese, a flammable liquid can occur as a form

f mist and also as a vapor. Some of the sub-ances may need only very little energy toact. Normally gases and vapors are the most

ammable. In flammable materials, solidsan be in the form of dust, fiber, or flock. Theaction of flammable solids causes a rapid

temperature rise and high pressure. Normallysolids need more energy to react than gasesbut the energy of the reaction causes heavyexplosions.

The ignition of an explosion can be started byseveral sources:

Hot surfaces Flames and hot gases Mechanically generated sparks Electrical installations Equalizing currents Static electricity Lightning Electromagnetic waves Optical radiation Ionizing radiation Ultrasound Adiabatic compression and shock waves Exothermal reactions

Ensto recognizes this by taking all due cau-tion to minimize the risk of ignition causedby materials or by the design of an enclosure.The structure must be designed to eliminateall electro-static charges. Generally chargesare formed when two materials with differentcharges come into contact with each other.A larger contact area or greater distance be-tween the surfaces of the materials touch-ing each other increases the likelihood of acharge. Danger of an increasing charge inmaterial increases when the resistivity of theother material decreases.

If the material has a charge, an electro-staticdischarge may occur. A charge can be dis-charged in many ways, but the most commonways are spark discharges and brush discharg-

es. Both of these can cause a dangerous igni-tion, because the energy released can ignitegases and vapors. A spark discharge occurswhen the charge between two conductors indifferent potentials increases to a sufficientlevel. In a brush discharge, energy is releasedwhen a charged object is approached by around conductive object.

These charges can be eliminated effectivelyby using potential equalisation or grounding.Potential equalisation refers to the connec-tion of two conductive objects to each other.Grounding refers to the connection of a con-ductive object to the ground potential. Dis-charging must be used when the protectivestructure is used in a space where explosiongroup IIC gases are present and the thicknessof a non-conductive surface layer exceeds 0.2mm or the surface resistivity exceeds 1 G. Inequipment class two it must be ensured thatthe projection surface area of non-conductivecomponents, such as value plates and stickers,does not exceed 20 cm2. If the non-conductivesurface is surrounded by an grounded frame,its surface area can be multiplied by four.

The specification contains three explosiongroups. These groups are based on the meas-ured ignition capabilities of gases and vaporsat a certain temperature. The classificationis split into sections I and II, and groups des-ignated A, B, and C. For example, group Acontains common alcohols with a low flashtemperature and group C contains gaseoushydrogen with a relatively high flash tempera-ture.

The table on the right shows examples of theignition temperatures of gases and vapors indifferent temperature classes and explosionsubdivisions.

Explosion groupsCLASSIFICATION OF EXPLOSION GROUPS

Temperature class Ignition

temperature

IIA IIB IIC

T1 > 450 C

Acetone

Benzene

Ethane

MethanolPhenol

Propane

Toulene

Car bo n m on oxide Hyd ro gen

T2 > 300 ... 450 C

Ethyl

Amyl asetateButane

Butyl

Cyclohexane

Ethylene Asetylene

T3 > 200 ... 300 C

PetroleumDiesel fuel

Jet fuel

Hexane

Butyl acrylate

Ethylene glycol

T4 > 135 ... 200 CAcetaldehyde Ethyl ether Carbon bisulfide

T5 > 100 ... 135 CT6 > 85 ... 100 C


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Risk management

Product design phase

Situation of use

sk assessment should always be carried outevery situation individually, in accordance

ith EN 1050. The element of risk assessmentllows the steps given by the standard:Identification of hazards such as flammablesubstances and the possibility of ignition Identification of possible zones (hazardousatmospheres)Identification of possible ignition sources

and their capability for ignitiond) Identification of possible effects of an explo-

sione) Risk management and evaluationf) Actions to minimize the risks

An essential part of atmosphere classifica-tion is a truthful classification of emissionsources. This classification is performed byclassifying the emission source as continu-ous, primary, or secondary. When the emis-sion source is continuous, such as an open

liquid surface, emissions are released intothe atmosphere continuously and the emis-sion is either long-term or repeating. Whenthe emission source is primary, such asleaking seals and ventilation openings, theprobability for emission is temporary duringnormal use. Secondary emissions are notnormally released, or if they are, they occurextremely rarely and are short-term. In thiscase the sources may be dry seals, pipe con-nectors, and flanges.

To ensure the safety of a product, such as a machine, it must be

designed so that the use of the machine is as safe as possible.

The end user must not be required to take their own protec-

tive measures. The end user must follow all general instruc-

tions provided in the designers usage instructions. Two main

phases must be met to make the product as safe as possible.

The standard specifies that the item must beinspected visually, closely, and in detail, whichrefers to opening the enclosure and ensur-ing that the surrounding area is in a stabilestate. A protocol must be kept of all inspec-tions. The maximum inspection interval forEx equipment is three years, but also in thiscase it must be evaluated how wearing theequipment use is. If the equipment is mov-able, the inspection must be performed every12 months. Enclosures opened often must beinspected every 6 months. Ensto declares thatthe spare parts required to maintain the prod-uct classification will be kept available for all

Ex area inspections and maintenance

enclosures supplied by Ensto. It must be notedthat all parts used must be approved by theoriginal manufacturer and that they must beinstalled according to standard IEC/EN 60079-19 and the manufacturers instructions. WhenEx e equipment is repaired, the following mustbe noted:

IP class must not change Temperature class must not change. Shock endurance must not change. Distance of movable and fixed parts must not

change. Surface treatment must have no effect on

the temperature class, e.g. product markingsmust not be covered.

Transparent parts must be replaced, theymust not be repaired.

Parts of the protective enclosure, such as thegrounding, door, base, seals, windows, locks,and threaded parts can be replaced by origi-nal parts supplied by the manufacturer. Theoriginal structure and intended use of the de-vice must not change. The availability of criticalspare parts for Enstos Cubo X series should beensured through discussion with Enstos salespersonnel or customer service.

Electrical installations of Ex areas must be carried out according

to IEC/EN 60079-17. Electrical installations in explosive areas are

specifically designed to be suitable for Ex areas and the condi-

tions of use. Taking the conditions of use into account, it must

be ensured that the special properties designed are preserved

for the entire lifecycle. This is the reason why the installationsmust be inspected and maintained regularly after the commis-

sioning inspection by professional personnel.

Reached

product safety

in design phase: Naturally safe structure

and solutions

The necessary security

measures

Safety markings and

warnings

Reached safety

in situations

of use: Product usage according

to instructions

Knowledge of user

Personal safety

Work management

The overall safety

of the product:

EC directives

(94/9/EC)IEC 60079-0, EN 60079-0

EC directives

(99/92/EC)


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Basics: Classification of zonesAn explosion protection document is a docu-ment which the party responsible for operationmust draw up concerning the production envi-ronment. This document contains the area clas-sifications for all areas. Dangers caused by explo-sive mixtures of air and explosive materials mustbe investigated in determining area classificati-on. The report describes how the formation ofan explosive mixture or an ignition source, suchas a spark, should be prevented. (1999/92/EC)

Dust atmospheresDust atmospheres, in accordance with IEC60079-10-2 and IEC 60079-31, are classified indifferent zones. IEC 60079 gives guidance onhow to identify and classify the areas where ha-zards from dust can occur. The area classificati-on method evaluates the materials properties,

emission sources, dust layers and formation pro-bability of an explosive dust-air mixture.

Zone 20:An area where combustible dust, as a cloud, ispresent continuously or frequently during nor-mal operation. Areas, such as the inside parts ofequipment, e.g. mixers, silos, filters, mills, transferpipes, closed conveyors.

Zone 21:An area where combustible dust, as a cloud, islikely to occur during normal operation. Areas,such as filling and emptying areas and placeswhere dust accumulates and the probability forformation of an air-dust mixture is high.

Zone 22:An area where combustible dust clouds mayoccur infrequently and persist for only short pe-riods. Areas such as storage facilities of closedpackages, outlet sides of air filters, surroundingsof rarely opened equipment. And if the probabi-lity for formation of an air-dust mixture is high inabnormal conditions.

Gas atmospheresGas atmospheres are classified as follows accor-ding to IEC 60079-10-1 and IEC 60079-7.

Zone 0:An area where an explosive mixture of air andflammable gas, vapor, or particles is present con-tinuously, for long periods, or frequently.

Zone 1:An area where the occasional occurrence of anexplosive mixture of air and flammable gas, va-por, or particles is likely.

Zone 2:An area where the occasional occurrence of anexplosive mixture of air and flammable gas, va-por, or particles is not likely but rare and onlyshort-term.

Area classes are divided into

wo categories based on the

material type. The categories

re air/gas mixtures, vapor,

articles and air/dust mixtu-

es. Area classifications clarify

he protection principles and

evels for areas specified in

he explosion protection do-

ument. This ensures correct

election of the protection

rinciple and maintains cost-

fficiency.

Equipment category 1Design and structure of the equipment ensu-re an extremely high level of safety when theoperating conditions specified by the manu-facturer are observed. The equipment mustbe able to ensure sufficient level of safetyeven in rare fault situations. The equipmentmust ensure two protection methods inde-pendent of each other and safety must bemaintained even when two faults are presentsimultaneously. Equipment in this categoryare intended to be used in area classes 0 and20 and Ga and Da.

Equipment category 2Design and structure of the equipment ensurea high level of safety when the operating condi-tions specified by the manufacturer are obser-ved. The equipment must be able to ensure asufficient level of safety during repeated errorsituations and normal equipment fault situa-tions. Equipment in this category are intendedto be used in area classes 1 and 21 and Gb andDb.

Equipment category 3Design and structure of the equipment ensurea normal level of safety when the operatingconditions specified by the manufacturer areobserved. The equipment must be able to en-sure a sufficient level of safety during normaloperation. Often the manufacturers declarati-on of conformity is sufficient and third-partyapproval is not required. Equipment in this ca-tegory are intended to be used in area classes2 and 22, and Gc and Dc.

Equipment categories

The Atex equipment groups and their classifications are di -

vided into two groups and normal industrial use in accord-

ance with 94/9/EC Equipment group II is divided into three

categories by the equipment directive. Equipment in higher

categories can be used in lower categories, but equipment

in equipment group II cannot be used in equipment group I

spaces. Equipment in equipment group I is intended for use inunderground parts of mines.


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Equipment protection levels (EPL)

for Ex equipment

C 60079-14 specifies an alternative wayo describe zones. EPL uses risk evaluation

equipment selection and, when compa-d to CENELEC described above, is a bet-

ter way to mark area classifications. It mustalso be noted that EPL aims for a uniformrisk evaluation, not country-specific mo-dels.

Protection levels and Ex structures for flammable gases:

Protection levels and Ex structures for flammable dusts:

Type of protection Code Standards EPL

Intrinsically safe ia IEC 60079-11

GaEncapsulation ma IEC 60079-18

Two independent types of protection, each meeting EPL Gb IEC 60079-26

Flameproof enclosures d IEC 60079-1

Gb

Increased safety e IEC 60079-7

Intrinsically safe ib IEC 60079-11

Encapsulation mb IEC 60079-18

Oil immersion o IEC 60079-6

Pressurized enclosures p IEC 60079-26

Powder filling q IEC 60079-5

Intrinsically safe ic IEC 60079-11 Gc

Encapsulation mc IEC 60079-18

Non-sparking n IEC 60079-15

Restricted breathing nR IEC 60079-15

Energy limitation nL IEC 60079-15

Sparking equipment nC IEC 60079-2

Type of protection Code Standards EPL

Intrinsically safe id IEC 60079-11

DaEncapsulation mD IEC 60079-18

Increased safety tD IEC 60079-31

Intrinsically safe iD IEC 60079-11

Db

Encapsulation mD IEC 60079-18


Pressurized enclosures pD IEC 60079-4

Intrinsically safe iD IEC 60079-11 Dc

Encapsulation mD IEC 60079-18


Pressurized enclosures pD IEC 60079-4

Zone EPL-marking

Ga

Ga or Gb

Ga, Gb or Gc

0 Da

1 Da or Db

2 Da, Db or Dc


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Temperature

emperature class and maximum

urface temperature

accordance with IEC 60079-0, the tempera-re class specifies how high the surface tem-

erature can rise without the gas, vapor, mist,

or dust reaching its flash point and exploding.The relation between the surface temperatureand the distance between the heat source andthe protective structure is normally linear. Thisassumption cannot be relied on in all cases, sothe surface temperature must be determinedby tests and the temperature group selected

accordingly. The flash temperature of gasesand vapors is generally known to a high de-gree of accuracy. The highest allowable sur-face temperatures for each group are present-ed in the table below. These are the lowestallowable flash temperatures of gases, vapors,or dusts present in the environment:

safety factor must be used when calculatinge temperature of dust-air mixture and dustyers. For a dust-air mixture, the safety margincalculated by multiplying the ignition tem-

Temperature groups or flammability groups refer to tem-

peratures which the equipment or protective structure sur-

face must not reach under any conditions. This temperature

limit prevents the gas or vapor flash temperature from being

reached. The temperature group and highest allowable sur-

face temperature are usually determined by combined test-ing of the protective structure and the component.

Te mp er at ur e c la ss I gn it io n t em pe ra tu re P er mi ss ib le s ur fa ce t em pe ra tu re

of the electrical equipment

T1 > 450 C 450 C

T2 > 300 .. 450 C 300 C

T3 > 200 .. 300 C 200 C

T4 > 135 .. 200 C 135 C

T5 > 100 .. 135 C 100 C

T6 > 85 .. 100 C 85 C

emperature classification of gas atmosphere.

perature of the mixture by 0.67. When the dustlayer thickness exceeds 5 mm, the safety mar-gin is calculated by deducting 75K (Kelvin de-grees) from the maximum tested temperature

causing a dust explosion in the atmosphere. Inmost cases a shock or friction produces sparks,which cause the dust explosion as indicated inthe table.

The ignition properties of the dust presentmust be known when evaluating dust atmos-pheres. Different types of dust mixtures arelisted in the table below. T.ign-cl. is the lowestsurface temperature required to ignite a dustcloud. T.ign-lay is the lowest surface tempera-ture required to ignite a dust layer, and E.minis the lowest electric spark energy capable ofigniting the most flammable dust-air mixture.

Mechanical sparks

Electrical equipment

Other or unknown

Glowing spots

Statical electricity

Friction

Fire

Hot surfaces

Self-ignition

Welding

Examples of the ignition properties of dusts

The most common causes of ignition

Substance T.ign-cl T.ign-lay E.min

Wood 410 C 200 C 100 mJ

Flour 380 C 300 C 30 mJ

Brown coal 380 C 225 C -

Hard coal 500 C 240 C 1000 mJ

Aluminum 560 C 340 C 5 mJ

Sulfur 240 C 250 C 10 mJ


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Types of protection

The protection principle must be selected in accordance with

tables on page 13 to meet the requirements o f area or equip-

ment classification. The protection methods for Ex e and Ex i

principles with No ignition sources and for Ex d and Ex t princi-

ples with Isolation from ignition sources are presented below.

Requirements of standards IEC 60079-17 and IEC 60079-14must be taken into account when servicing equipment with

different protection principles.

Ex dEx d protection type refers to a protection type,which withstands the explosion pressure. Theprotection type must be in accordance withstandard IEC/EN 60079-1, which makes it suit-able for Zones 1 and 2. Spark-generating com-ponents, such as relays and switches, can be in-stalled inside the enclosure. These componentsdo not need to be approved for Ex areas. Enclo-sure protection is based on suffocating the ex-plosion inside the enclosure through groovesin the enclosure so that flammable material isnot released outside. The enclosure is alwaysmanufactured of metal and only metallic Ex dapproved cable glands can be used.

Ex iEx i protection type refers to an intrinsically safeprotection type. The protection type must bein accordance with standard IEC/EN 60079-11,making it suitable for area classes 0, 1, and 2.The equipments electrical circuit energy mustbe below the dangerous minimum ignition en-ergy (MIE) even in fault situations. In this casethe power is restricted before it is transferred tothe Ex area. Sparks are not generated even inshort-circuit situations. An accurate specifica-tion for Ex i enclosures or markings does notexist, but Ensto recommends the use of Ex e en-closures and light-blue color coding of cables,cable glands, and equipment inside the enclo-sure. It is recommended that Ex i enclosures arevisually different from normal enclosures. Addi-

x ex e protection type refers to an increasedafety protection type. The protection type

ust be in accordance with standard IEC/EN0079-7, making it suitable for Zones 1 andOnly intrinsically safe Ex approved compo-

ents are allowed to be installed inside thenclosure. Suitability of this structure for theea class must be ensured through electri-

al design and technical solutions so that thequipment does not produce sparks and can-ot overheat exceeding the temperature lim-s. An Ex e enclosure can be manufactured of

Ex tEx t protection type refers to a dust-proof enclo-sure. The protection type must be in accordancewith standard IEC/EN 60079-31, making it suit-able for area classes 0, 1, and 2. Spark-generatingcomponents, such as relays and switches, canbe installed inside the enclosure. These com-ponents do not need to be approved for Ex ar-eas. The protection type must prevent harmfulamounts of dust from entering the enclosure.Entry of dust can also be completely prevented.Ensto recommends the use of Ex e enclosures.

Typically Ex tD equipment is used in many in-dustrial applications, such as control and au-

Typical uses are Ex d motors, switch parts ofsafety switches, switch parts of control switch-es, Ex heaters, Ex connection boxes, and Exlighting fixtures.

The enclosure can be repaired if the protectionproperties do not change and if the enclosurewithstands the over-pressure test after the re-pair. It must be noted that seal materials mustnot be changed and extra holes must not bemade in the enclosure. Transparent parts mustnot be repaired, and surface treatment mustnot cover the protective openings.

tionally the circuits should be color-coded andvisually different from other electrical circuits.

Typically Ex i equipment is used in automationsystems. However, it is not suitable for largepowers.

Protection class must not change when Ex iequipment is repaired. Also the surface andthe air gaps must remain unchanged. Use ofreserve fuses with the same value as the oldones is allowed in the equipment. Diode bar-riers must not be repaired but they must bereplaced. Internal wiring must not be modified.Operation of the structure must be ensured af-ter servicing by performing a one-minute volt-age test with 500 V.

either metal or plastic. Ex e or Ex d approvedcable glands can be used in these enclosures.

Typical uses are Ex e motors, safety and con-trol enclosures, Ex terminal blocks, Ex terminalblock enclosures, enclosure parts of Ex light-ing fixtures and Ex e bushes and sealing plugs.

The enclosure can be repaired if the sealingclass and the temperature class do not changebecause of e.g. painting. Paragraph 2.4 con-tains more detailed specifications for serviceprocedures.

tomation systems, and it is possible that somesurfaces become hot.

The condition of enclosure seals must be in-spected when repairing Ex t equipment. If aseal is damaged, the seal must be changedto a new original spare part manufacturedof the same material. Enclosure shock resist-ance must not deteriorate. Distances of fixedparts must not change in repairs. If the itembeing repaired is a lighting fixture, all partsused must be approved by the manuf acturerand the maximum power must not be ex-ceeded.


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Marking

Manufacturers name and address CE marking Serial or type marking Serial number, if applicable Year of manufacture Equipment group and class Marking of the gas (G) and/or dust class (D) Other markings related to safe use of the pro-

duct

The manufacturer must have the required

ATEX documents to be able to provide cor-rect information on the product and to sellthe product as suitable for Ex areas in the EU.These documents are the EU Declaration ofConformity for products or the Certificate ofConformity for components. The manufac-turer must also produce installation, use, andmaintenance instructions for the product.Figure 2.1 illustrates the marking of a protec-tion principle, which must accompany theproduct. (94/9/EC)

Marking and documentation

equirements of the ATEXquipment Directive provide

he user with information on

he products properties. The

ollowing information must

e marked on the product:

Figure Example of a protection

principle marking according to

the EN and IEC standards.The Certificate of Conformity for products,components and products can only be is-sued by a testing facility accredited by the EUmember states. These independent testingfacilities evaluate conformity as specified bythe Directive.

North American equipment certification

requirements for hazardous locations

NORTH AMERICA

Typical North American Marking

NEC 500 NEC 505

Class I, Division 1, Groups A&B T4 Class I, Zone 0 , AEx ia IIC T4

HazardClass

HazardClass

AreaClassification

Approved to US Standards

ProtectionConceptCode

GasGroup

AreaClassification

TemperatureClass

TemperatureClass

GasGroup

ATMOSPHERE GROUPS

Substance NEC 505 NEC 500 Hazard Class

Acetylene IIC Group A

Class I

Flammable Gases

Hydrogen IIC Group B

Ethylene IIB Group C

Propane IIA Group D

Methane (mining) Group D

Combustible Metal Dusts Group EClass II

Combustible

Dusts

Combustible Carbonaceous Dusts Group F

Combustible Dusts not in Group E or F

(Flour, Grain, Wood, Plastics, Chemicals)Group G

Combustible Fibers and FlyingsClass III

Fibers and Flyings

TEMPERATURE CLASSIFICATION

Max. Surface Temperature IEC - Group II NEC 505 NEC 500 CEC

450 C (842F) T1 T1 T1

300 C (572F)

T2 T2

T2

280 C (536F) T2A

260 C (500F) T2B

230 C (446F) T2C

215 C (419F) T2D

200 C (392F)

T3 T3

T3

180 C (356F) T3A

165 C (329F) T3B

160 C (320F) T3C

135 C (275F)T4 T4

T4

120 C (248F) T4A

100 C (212F) T5 T5 T5

85 C (185F) T6 T6 T6

II 2 G Ex d IIC T4 Gb

Complies with European Direc


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PROTECTION CONCEPTS

Type of

Protection

Code Cty Class Division/Zone Standard Basic Concept

of Protection

Electrical Equipment for Flammable Gas, Vapors and Mist - Class I

General

Requirements AEx

Ex

US

CA

US

CA

Class I

Class I

Class I

Class I

Division 1 & 2

Division 1 & 2

Division 1 & 2

Division 1 & 2

FM 3600

ISA 60079-0

CSA 60079-0

ncreasedSafety

AEx eEx e

USCA

Class IClass I

Zone 1Zone 1

ISA 60079-7CSA E60079-7

no arcs, sparcs

or hot surfacesNon-Incendive

(NI)

(NI)

US

CA

Class I

Class I

Division 2

Division 2

ISA 12.12.01/FM 3611

C22.2 No. 213

Non-SparkingAEx nA

EX nA

US

CA

Class I

Class I

Zone 2

Zone 2

ISA 60079-15

CSA E60079-15

Explosion Proof(XP)

(XP)

US

CA

Class I

Class I

Division 1

Division 1

UL 1203

C22.2 No. 30

Contain the

explosion and

extinguish the

flame

Flame ProofAEx d

Ex d

US

CA

Class I

Class I

Zone 1

Zone 1

ISA 60079-1

CSA 60079-1

Power FilledAEx q

Ex q

US

CA

Class I

Class I

Zone 1

Zone 1

ISA 60079-5

CSA E60079-5

Enclosed BreakAEx nCEx nC

USCA

Class IClass I

Zone 2Zone 2

ISA 60079-15CSA E60079-15

ntrinsic Safety

(IS)

(IS)

AEx ia

AEx ib

EX ia

Ex ib

US

CA

US

US

CA

CA

Class I

Class I

Class I

Class I

Class I

Class I

Division 1

Division 1

Zone 0

Zone 1

Zone 0

Zone 1

UL 913 / FM 3610

C22.2 No. 157

ISA 60079-11

ISA 60079-11

CSA E60079-11

CSA E60079-11

Limit energy of

sparks andsurface

temperature

Limited EnergyAEx nCEx nL

USCA

Class IClass I

Zone 2Zone 2

ISA 60079-15CSA E60079-15

Pressurized

Type X

Type X

Type Y

Type Y

Type ZType Z

AEx px

Ex px

AEx py

Ex py

AEx pzEx pz

US

CA

US

CA

USCA

US

CA

US

CA

USCA

Class I

Class I

Class I

Class I

Class IClass I

Class I

Class I

Class I

Class I

Class IClass I

Division 1

Division 1

Division 1

Division 1

Division 2Division 2

Zone 1

Zone 1

Zone 1

Zone 1

Zone 2Zone 2

NFPA 496 (FM 3620)

NFPA 496

NFPA 496 (FM 3620)

NFPA 496

NFPA 496 (FM 3620)NFPA 496

ISA 60079-2

CSA E60079-2

ISA 60079-2

CSA E60079-2

ISA 60079-2CSA E60079-2

Keep flamablegas out

Restricted

Breathing

AEx nR

Ex nR

US

CA

Class I

Class I

Zone 2

Zone 2

ISA 60079-15

CSA E60079-15

Encapsulated

AEx ma

AEx m

Ex m

AEx mb

US

US

CA

US

Class I

Class I

Class I

Class I

Zone 0

Zone 1

Zone 1

Zone 1

ISA 60079-18

ISA 60079-18

CSA E60079-18

ISA 60079-18

Oil ImmersionAEx oEX o

USCA

Class IClass I

Zone 1Zone 1

ISA 60079-6CSA E60079-6

Electrical Equipment for Combustible Dust - Class II & Class III

General

Requirements

Ex

US

CA

US

CAUS

Class II

Class II

Class III

Class III

Division 1 & 2

Division 1 & 2

Division 1 & 2

Division 1 & 2Zone 20, 21, 22

FM 3600

FM 3600

ISA 60079-0

Dust Ignition

Proof

(DIP) US

CA

Class II

Class II

Division 1

Division 1

UL 1203

CSA C22.2 No. 25

Keep

combustible

dust out

Dust Protected(NI) US

CAClass IIClass II


ISA 12.12.01 / FM 3611CSA C22.2 No. 25

Protection by

Enclosure

AEx tD(DIP) A21

(DIP) A22

USCA

CA

Class II

Class II

Zone 21Division 1

Division 2

ISA 60079-31CSA E61241-1-1

CSA E61241-1-1

Fiber & Flying

Protection

US

CA

Class III

Class III

Division 1 & 2

Division 1 & 2

UL 1203 / ISA 12.12.01

CSA C22.2 No. 25

EncapsulationAEx maD

AEx mbD

US

US

Zone 20

Zone 21

ISA 61241-18

ISA 61241-18

Pressurization

(PX)

(PX)

(PY)(PY)

(PZ)

(PZ)

AEx pD

US

CA

USCA

US

CA

US

Class II

Class II

Class IIClass II

Class II

Class II

Division 1

Division 1


Division 2

Division 2

Zone 21

NFPA 496 (FM 3620)

NFPA 496

NFPA 496 (FM 3620)NFPA 496

NFPA 496 (FM 3620)

NFPA 496

ISA 61241-2

ntrinsic Safety

(IS)(IS)

AEx iaD

AEx ibD

(IS)

(IS)

USCA

US

US

US

CA

Class IIClass II

Class III

Class III


Zone 20

Zone 21

Division 1

Division 1

UL 913 / FM 3610

CSA C22.2 No. 157

ISA 61241-11

ISA 61241-11

UL 913 / FM 3610

CSA C22.2 No. 157

Limit

energy of

sparks and

surface

temperature

ENCLOSURE TYPE RATINGS

Type Brief Definition Area

1 General Purpose Indoor

2 Protection against angled dripping water Indoor

3, 3R, 3S Protection against rain, snow Indoor / Outdoor

4, 4X Protection against rain, snow, hose directed water Indoor / Outdoor

5 Protection against angled dripping water, dust, fibers, flyings Indoor

6 Protection against temporary submersion Indoor / Outdoor

6P Protection against prolonged submersion Indoor / Outdoor

12, 12K Protection against circulating dust, fibers, flyings Indoor

13 Protection against circulating dust, fibers, flyings, seepage Indoor

CLASSIFICATION OF DIVISIONS AND ZONES

Type of Area NEC and CEC* ATEX and IEC Definitions

Continous

hazardDivision 1 Zone 0 / Zone 20

A place in which an explosive atmosphere is

continually presentIntermittent

hazardDivision 1 Zone 1 / Zone 21


likely to occur in normal operationHazard under

abnormal

conditions

Division 2 Zone 2 / Zone 22


not likely to occur in normal operation, but

may occur for short periods


12/15

2 23

The road to conformity for ATEX Selecting cable gland

ther than internal combustion engines and electrial equipmentnternal combustion engines and electrical equipment

nd all autonomous protective systemsNotified body

PLANNING

PRODUCTION

Ex-equipment

Manufacturers choice

All categories3)Category 1 and M 1 2)Category 2 and M 2 1)Category 2 and M 2 Categor y 3

DESIGN

Unit verification AnnexIX

Internal control of pro-

duction Annex VIII (A)

Internal control ofproduction, plus send

dossier to N.B. AnnexVIII (A)

EC type examination

Annex III (B)

EC type examination

Annex III (B)

NB)Con-formityto type,

Annex VI(C)

NB)Pro-

ductionqual-ity as-

surance,Annex VII

(E)

NB)Pro-

ducationqual-ity as-

surence,Annex VII

(E)

NB)Prod-uct veri-fication,

AnnexV (F)

Declaration of conformity

Annex X

START

Zone 2Is equipment Ex i

concept?Is equipment Ex d

concept?Zone 1?

YES NO

NO NONO

Is area zoned?

Use blue coloredcable glands

Ex e concept Ex e conceptRefer to Ex d cable

selector chartEx n* or N concept

Gland type

Plastic Brass

Use non-certified cable glands*refer to note2Use certified cable glands

Use a suitable

flameproof cablegland with a sealing

ring. (Gland with

elastomeric seals)

YES YES

YES


13/15


14/15

6 27

Notes

gal notice

he information in this brochure is to the best of Enstos knowledge and belief correct and reliable. We reserve the right to make changes in the specifications, materials

d production methods without further notice. Be aware of that you have to evaluate independently the suitability of each product for the intended application.

sto does not give any assurance of any particular quality or performance. Our responsibilities for the products are set forth in the Orgalime S 2000 General Conditions

r the Supply of Mechanical, Electrical and Electronic Products. The products shall be installed only by a competent person having nationally required knowledge.

sto is not responsible for its distributors or for any misuse, incorrect installation or ignored national safety or other national provisions.

opyright Ensto Oy 2011, Ensto

Download or order the Ensto Cubo X

brochure from www.ensto.com/atex

nsto saves your energy

sto is a family business and an international electricity company specializing in the development, manufacture and marketing of electrical systems and supplies for the

stribution of electrical power as well as electrical applications.


15/15

Ensto Finland oy

Ensio miettisen katu 2, P.o. box 77FIN-06101 Porvoo, Finland

[email protected]

www.ensto.com

IS6EN/09/2011/B9

Documents

24542 Basics of Atex