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Explosion protection Fundamentals

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2 Introduction

The full range of Ex applications under controlIntroduction

In many industries, the manufacture, processing, trans-port, or storage of combustible materials results in the cre-ation, or release into the surrounding environment, of gases, vapors, or mist. Other processes create combustible dust. An explosive atmosphere can form in conjunction with the oxygen in the air, resulting in an explosion if ignit-ed.

Particularly in areas such as the chemical and petrochemical industries, the transport of crude oil and natural gas, the min-ing industry, milling (e.g. grain and granular solids) and many other branches of industry, this can result in serious injury to personnel and damage to equipment.

To guarantee the highest possible level of safety in these areas, the legislatures of most countries have developed appropriate obligations in the form of laws, regulations and standards. In the course of globalization, it has been possible to make significant progress towards harmonizing guidelines for explosion protection.

With the Directive 94/9/EU the European Union creates the prerequisites for complete standardization because all new devices must be approved in accordance with this directive since July 1, 2003.

The brochure "Explosion Protection Fundamentals" is designed to provide users and interested readers with an overview of explosion protection in conjunction with electrical equipment and systems. It also assists in decoding device labels.

However, it does not replace intensive study of the relevant fundamentals and guidelines when planning and installing electrical systems.

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Introduction 3

Index

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Physical principles and parameters . . . . . . . . . . . . . 4

Legislative basis and standards . . . . . . . . . . . . . . . . 8

Classification of explosion-protected equipment. . . . . . . . . . . . . . . 10

Setting up and operating electrical systems. . . . . 16

Intrinsic safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Ex protection in North AmericaComparison of zones / divisions . . . . . . . . . . . . . . . 19

Safety ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Approval and test centers . . . . . . . . . . . . . . . . . . . . 24

Product range of ET 200 for hazardous areas . . . . . . . . . . . . . . . . . . . 26

Further information. . . . . . . . . . . . . . . . . . . . . . . . . 31


4 Physical fundamentals and parameters

3

1

2

Integrated explosion protection

Prevent the formation of potentially

explosive atmospheres

Prevent the ignitionof potentially explosive

atmospheres

Restrict the effectsof an explosion

to a negligible level

EXPLOSION

Combustiblesubstances

Ignition source

Oxygen

Physical fundamentals and parameters

Explosion

An explosion is the sudden chemical reaction of a combustible substance with oxygen, involving the release of high energy. Combustible substances can be present in the form of gases, mist, vapor, or dust. An explosion can only take place if the fol-lowing three factors coincide:

1. Combustible substance (in the relevant distribution and concentration)

2. Oxygen (in the air)

3. Source of ignition (e.g. electrical spark)

Primary and secondary explosion protection

The principle of integrated explosion protection requires all explosion protection measures to be carried out in a defined order. A distinction is made here between primary and sec-ondary protective measures.

Primary explosion protection covers all measures that prevent the formation of a potentially explosive atmosphere.

What protective measures can be taken to ensure that the risk of an explosion will be minimized?

■ Avoidance of combustible substances

■ Inerting (addition of nitrogen, carbon dioxide, etc.)

■ Limiting of the concentration

■ Improved ventilation

Secondary explosion protection is required if the explosion hazard cannot be removed or can only be partially removed using primary explosion protection measures.


Physical fundamentals and parameters 5

Air concentration100 Vol.%

100 Vol.%

0 Vol.%

0 Vol.% Concentration of combustible substance

Mixture too lean:No combustion

Mixture too rich:Partial deflagrationNo explosion

Explosion limit

GArea subject to explosion

The consideration of technical safety parameters is necessary for the characterization of potential dangers:

Flash point

The flash point for flammable liquids specifies the lowest tem-perature at which a vapor-air mixture forms over the surface of the liquid that can be ignited by a separate source.

If the flash point of such a flammable liquid is significantly above the maximum occurring temperatures, a potentially explosive atmosphere cannot form there. However, the flash point of a mixture of different liquids can also be lower than the flash point of the individual components.

In technical regulations, flammable liquids are divided into four hazard classes:

Explosion limit

Combustible substances form a potentially explosive atmo-sphere when they are present within a certain range of con-centration.

If the concentration is too low (lean mixture) and if the con-centration is too high (rich mixture) an explosion does not take place. Instead slow burning takes place, or no burning at all.

Only in the area between the upper and the lower explosion limit does the mixture react explosively if ignited.

The explosion limits depend on the surrounding pressure and the proportion of oxygen in the air (see the table below).

We refer to a deflagration, explosion, or detonation, depend-ing on the speed of combustion.

A potentially explosive atmosphere is present if ignition repre-sents a hazard for personnel or materials.

A potentially explosive atmosphere, even one of low volume, can result in hazardous explosions in an enclosed space.

Explosion limits of combustible substances

Hazard class Flash point

AI < 21 °C

AII 21…55 °C

AIII > 55…100 °C

B < 21°C, soluble in water at 15 °C

Substance designation

Lower explosion limit [Vol. %]

Upper explosion limit [Vol. %]

Acetylene 2.3 78.0 (self-decomposing)

Ethylene 2.3 32.4

Petrol ~ 0.6 ~ 8

Benzene 1,2 8

Natural gas 4.0 (7.0) 13.0 (17.0)

Heating oil/diesel ~ 0.6 ~ 6.5

Methane 4.4 16.5

Propane 1.7 10.9

Carbon bisulfide 0.6 60.0

City gas 4.0 (6.0) 30.0 (40.0)

Hydrogen 4.0 77.0


6 Physical fundamentals and parameters

Physical fundamentals and parameters

Dust

In industrial environments, e.g. in chemical factories or corn mills, solids are frequently encountered in fine form – e.g. as dust.

Dust is defined in DIN EN 50281-1-2 as "small solid particles in the atmosphere which are deposited because of their own weight, but which still remain in the atmosphere for a period of time as a dust/air mixture". Deposits of dust are comparable with a porous body, and have a hollow space of up to 90%. If the temperature of dust deposits is increased, the result may be spontaneous ignition of the combustible dust.

If dust deposits with a small grain size are whirled up, there is a danger of explosion. This increases as the size is reduced, since the surface area of the hollow space becomes larger. Dust explosions are frequently the result of whirled up glow-ing layers of dust which possess the basis for ignition. Explo-sions of gas or vapor mixtures with air can whirl up dust where the gas explosion then merges into a dust explosion. In collier-ies, explosions of methane gas frequently lead to explosions of coal dust whose effect was often greater than that of the gas explosion.

The danger of an explosion is prevented by using explosion-proof devices according to their suitability. The identification of the device category reflects the efficiency of explosion pro-tection, and thus the application in corresponding hazardous areas. The danger of explosive dust atmospheres and the se-lection of appropriate protective measures are assessed using safety parameters for the involved substances. Dusts are con-sidered according to two substance-specific properties:

■ ConductivityDusts are referred to as conductive if they have a specific electric resistance up to 10³ Ohmmeter.

■ CombustibilityCombustible dusts can burn or glow in air, and form explo-sive mixtures with air at atmospheric pressure and at tem-peratures from -20 to +60 °C.

Safety parameters for whirled-up dusts are, for example, the minimum ignition energy and the ignition temperature, whereas for deposited dusts, the glow temperature is a char-acteristic property.


Physical fundamentals and parameters 7

Minimum ignition energy

The application of a certain amount of energy is required to ignite a potentially explosive atmosphere.

The minimum energy is taken to be the lowest possible con-verted energy, for example, the discharge of a capacitor, that will ignite the relevant flammable mixture.

The minimum energy lies between approximately 10-5 J for hydrogen, and several Joules for certain dusts.

What can cause ignition?

■ Hot surfaces

■ Adiabatic compression

■ Ultrasound

■ Ionized radiation

■ Open flames

■ Chemical reaction

■ Optical radiation

■ Electromagnetic radiation

■ Electrostatic discharge

■ Sparks caused mechanically by friction or impact

■ Electrical sparks and arcs

■ Ionized radiation

Welding sparks,sheaf of

impact sparks in mills

Sheaf of grinding sparks

electrostaticdischarges,

impact sparks

rare

rarerare

Gases Dusts Practice-orientedignition source

Minimum ignition energy(mJ)

1000

100

10

1

0.1

0.01


8 Legislative basis and standards

Legislative basis and standards

Legislative basis of explosion protection

Globally, explosion protection is regulated by the legislatures of the individual countries. National differences in technical requirements and the required approvals for explosion-pro-tected devices are a significant hindrance to trade primarily for global players, and they require considerable overhead in development and approval testing.

For some time now, particularly among the leading industrial nations, there has therefore been interest in removing barriers to trade by harmonizing the appropriate technical standards, and in implementing uniform safety standards in parallel. Within the European Community, the harmonization process in the area of explosion protection is largely complete.

At the international level, the IEC is attempting to get closer to the aim of "a single global test and certificate" by introducing the IECEx Scheme.

EU Guidelines / CE Symbol

Protection against explosions is regulated by guidelines and regulations in the European Union. Electrical devices must satisfy the correspond-ing requirements within the EU. The manufacturer can attach the CE symbol to the respective device if these require-ments have been fulfilled. Any violations in this context are a punishable offence. The number of the notified office that has carried out the acceptance of the QA system, the number of the PTB test office in Braunschweig, for example, is added to this explosion protection symbol, in accordance with the ATEX guideline1). ATEX guidelines add non-electric device top-ics, e.g. regarding pneumatic drives, to the EU guidelines.

The respective equipment and systems have been classified as 'systems requiring monitoring' and must only make use of devices permitted for the purpose. Furthermore, start-up, changes and regular safety inspections must be carried out by institutes or authorized companies. The EU guidelines, which are enacted bindingly for all EU Member States, form the legal framework.

0102

Short name Full text Directive no.

Valid since End of transi-tion period

Low-voltage Directive

Council Directive of 19 February 1972 on the approximation of the laws of the Member States concerning electrical equipment for use within specific voltage limits

73/23/ECC 19.08.74 01.01.97

Modification 93/68/ECC 01.01.95 01.01.97

EMV-RL Council Directive of 3 May 1989 on the approximation of the laws of the Member states concerning electromagnetic compatibility

89/336/ECC 01.01.92 31.12.95

Modification 92/31/ECC 28.10.92 -

Modification 93/68/ECC 01.01.95 01.01.97

Machinery Directive Directive of the European Parliament and Council of 22 June 1998 on the approximation of the laws and administrative regulations of the Member States concerning machinery

98/37/EC(based on 89/392/ECC)

01.01.93 31.12.94

EX Directive (ATEX 100a)

Directive of the European Parliament and Council of 23 March 1994 on the approximation of laws of the Member States concerning equip-ment and protective systems intended for use in potentially explosive atmospheres

94/9/EC 01.03.96 30.06.03

Pressurized equipment Directive

Directive 97/23/EC of the European Parliament and Council of 29 May 1997 on the approximation of the laws of the Member States concern-ing pressurized equipment

97/23/EC 29.11.99 29.05.02

ATEX 137(old: ATEX 118a)

Minimum regulations for improving the health protection and safety of employees that could be endangered by potentially explosive atmospheres

1999/92/EC 16.12.99 30.06.03

1) ATEX is the abbreviation for ATmosphere EXplosable


Legislative basis and standards 9

National laws and regulations

In general, the EC directives are European law that must be incorporated by the individual member states unmodified and "one-to-one" by ratification. Directive 94/9/EC was adopted completely into the German explosion protection regulation ExVO. The underlying legislation for technical equipment is the Equipment Safety Law (GSG) to which ExVO is as a sepa-rate regulation (11. GSGV).

In contrast, ATEX 137 (Directive 1999/92/EC) contains only "Minimum regulations for improving the health protection and safety of employees that could be endangered by potentially explosive atmospheres", so that each EU member state can pass its own regulations beyond the minimum requirements. In the German Federal Republic, the contents of the directive have been implemented in factory safety legislation. In order to simplify the legislation, the contents of several earlier regu-lations have been simultaneously integrated into the factory safety legislation ('BetrSichVO'). From the area of explosion protection, these are:

■ The regulation concerning electrical installations in potentially explosive atmospheres (ElexV)

■ The acetylene regulation

■ The regulation concerning flammable liquids

These regulations became defunct when the factory safety legislation came into force on 01.01.2003.

Explosion protection guidelines (EX-RL) of the professional associations

In the "Guidelines for the prevention of hazards from poten-tially explosive atmospheres with listed examples" of the Ger-man Chemicals Professional Association, specific information is given on the hazards of potentially explosive atmospheres, and measures for their prevention or limitation are listed. Of special use are the examples of individual potentially explosive process plants in the most diverse industrial sectors in which these measures are listed in detail. Valuable suggestions and risk evaluations are available for planners and operators of such plants or similar process plants. While the EX Directives have no legal status, they are nevertheless to be regarded as important recommendations that can also be called upon for support in deciding legal questions in the event of damage.

Standards

There are a host of technical standards worldwide for the area of explosion protection. The standards environment is subject to constant modification. This is the result both of adaptation to technical progress and of increased safety demands in soci-ety.

International efforts at standardization also contribute, with the aim of achieving the most uniform global standards possi-ble and the resulting removal of barriers to trade.

EC standards

The standards for explosion protection valid in the European Community are created on the basis of the EC Directives under the leadership of CENELEC (European Committee for Electro-technical Standardization). CENELEC comprises the national committees of the member states. Since, in the meantime, standardization at international level gained greatly in impor-tance through the dynamism of the IEC (International Elec-tronic Commission), CENELEC has decided only to pass stan-dards in parallel with the IEC.

In practice, this means European standards in the area of elec-trical/electronic systems will now be created or redefined almost exclusively on the basis of IEC standards as harmonized EN standards. For the area of explosion protection, this affects primarily the standards of the EN 60079 series.

The numbers of harmonized European standards are struc-tured according to the following scheme:

IEC

At the international level, the IEC issues standards for explo-sion protection. The Technical Committee TC31 is responsible.

Standards for explosion protection are found in the IEC 60079-x series (previously IEC 79-x). The x represents the numbers of the individual technical standards, e.g. IEC 60079-11 for intrinsic safety.

Example Meaning

EN 50014 : 1997

Year of publication

Number of standard

Harmonized European standard


10 Classification of explosion-proof equipment

Classification of explosion-proof equipment

Identification

The identification of electrical equipment for hazardous areas should permit recognition of:

■ The vendor of the equipment

■ A designation by which it can be identified

■ The area of use- Below ground I

- Other areas II

■ Gases and vapors - G -, dusts - D - or mines - M -

■ The categories which indicate whether the device can be used for particular zones

■ The type(s) of protection with which the equipment complies

■ The testing agency which provided the test certificate, the standard (or its release version) with which the equipment complies – including the testing agency’s registration num-ber of the certificate and, if necessary, any special condi-tions which have to be observed.

■ In addition, the data should be provided which are usually required for such a device of industrial design.

Example of identification according to 94/9/EC

Example of a device identification

Example Meaning

> 0032 II 2D IP65 T80°C

Temperature range

Housing protection class

EX protection zone

Named agency for certification of the QA system according to 94/9/EC

Conformity symbol

Example Meaning

EXAMPLE COMPANY type 07-5103-.../... Identification of vendor and type

Ex II 2D IP65 T 80°CManufactured according to EN 50281-.-. Protected by enclosure, IP65 degree of protectionMax. surface temperature +80 °C

IBExU 00 ATEX 1081 Consecutive number of testing agency

ATEX generation

Year of test

Symbol of testing agency


Classification of explosion-proof equipment 11

Device groups/categories

Devices are classified into device groups:

■ Device group 1- in underground operations- in mines as well as open-cast operations- and their surface installations

■ Device group II- Devices for use in the other areas

Each device group contains equipment that is in turn assigned to different categories (Directive 94/9/EC). The category spec-ifies the zone in which the equipment may be used.

Comparison of device groups and categories

Zones

Areas subject to explosion hazard are divided into zones. Divi-sion into zones depends on the chronological and geographi-cal probability of the presence of a hazardous, potentially ex-plosive atmosphere.

Information and specifications for zone subdivision can be found in EN/ IEC 60079-10.

Equipment in areas where a constant explosion hazard exists (Zone 0) are subject to stricter requirements, and by contrast, equipment in less hazardous areas (Zone 1, Zone 2) is subject to less stringent requirements. In general, 95% of systems are installed in Zone 1 and only 5% of equipment is in Zone 0.

Subdivision of combustible substances into different zones

Device group I (Mining)

Category M1:Extremely high level of safety

M2:High level of safety

Level of danger Continuous, long-term and frequent danger

Occasion-al danger

Infrequent and short-term danger

Sufficient safety

Through 2 protective measures/in the event of 2 faults

Must be switched off in the presence of an Ex at-mosphere

Device group II (other areas subject to explosion hazard)

Cat. 1:xtremely high level of safety

2:High level of safety

3:Normal level of safety

Level of danger

Continuous, long-term and frequent danger

Occasional danger

Infrequent and short-term danger

Sufficient safety

Through 2 protective mea-sures/in the event of 2 faults

In the case of fre-quent device faults/in the event of one fault

In the case of fault-free opera-tion

Use Zone 0

Zone 20

Zone 1

Zone 21

Zone2

Zone22

Atmo-sphere

G (gas)

D (dust)

G D G D

Flammable gases, vapors and mist

Zone Category Equipment

Description

0 1G Hazardous, potentially explosive atmo-sphere present continuously and over extended periods.

1 2G1G

It is to be expected that a hazardous, po-tentially explosive atmosphere will only occur occasionally.

2 3G2G1G

It is to be expected that a hazardous, po-tentially explosive atmosphere will occur only rarely and then only for a short period.

Flammable dusts

Zone Category Equipment

Description

20 1D Areas where a potentially explosive at-mosphere comprising dust-air mixtures is present continuously, over extend-ed periods, or frequently.

21 2D1D

Areas where it is expected that a hazard-ous, potentially explosive atmosphere comprising dust-air mixtures will occur occasionally and for short periods.

22 3D2D1D

Areas in which it is not to be expected that a potentially explosive atmosphere will be caused by stirred-up dust. If this does occur, then in all probability only rarely and for a short period.



Classification of explosion-protected equipment

Types of protection

The protection types are design measures and electrical mea-sures carried out on the equipment to achieve explosion pro-tection in the areas subject to explosion hazard.

Protection types are secondary explosion protection mea-sures. The scope of the secondary explosion protection mea-sures depends on the probability of the occurrence of a haz-ardous, potentially explosive atmosphere.

Electrical equipment for areas subject to explosion hazard must comply with the general requirements of EN 50014 and the specific requirements for the relevant type of protection in which the equipment is listed.

The types of protection listed on the pages below are signifi-cant in accordance with EN 50014. All types of protection are based on different protection concepts.

Gases – Types of protection Application in zone

Type of protection L*) Schematicrepresentation

Basic principle Standard Examples 0 1 2

Generalrequirements

General requirements for the type and testing of electrical equipment intended for the Ex area

DIN EN 60079-0

Increased safety e Applies only to equipment, or its component parts, that normally does not create sparks or arcs, does not attain hazardous temperatures, and whose mains voltage does not exceed 1 kV

EN 50 019IEC 60 079-7FM 3600UL 2279

Terminals,connection boxes

■ ■

Flameproof enclo-sure

d If an explosion occurs inside the en-closure, the housing will withstand the pressure and the explosion will not be propagated outside the en-closure

EN 50 018IEC 60 079-1FM 3600UL 2279

Switchgear,Transformers

■ ■

Pressurized enclo-sure

p The ignition source is surrounded by a pressurized (minimum 0.5 mbar) protective gas – the sur-rounding atmosphere cannot enter

EN 50016IEC 60 079-2FM 3620NFPA 496

Control cabinets,switching cabinets ■ ■

Intrinsic safety i By limiting the energy in the circuit, the formation of impermissibly high temperatures sparks, or arcs is prevented

EN 50 020IEC 60 079-11FM 3610UL 2279

Actuators,sensors,PROFIBUS DPRS 485-iS

■ ■ ■

Oil immersion o Equipment or equipment parts are immersed in oil and thus separated from the Ex atmosphere

EN 50 015IEC 60 079-6FM 3600UL 2279

Transformers,switchgear ■ ■

Sand filling q Ignition source is buried in sand. The Ex atmosphere surrounding the housing cannot be ignited by an arc

EN 50 017IEC 60 079-5FM 3600UL 2279

Heater strips,capacitors

■ ■

Molding m By embedding the ignition source in a molding, it cannot ignite the Ex atmosphere

EN 50 028IEC 60 079-18FM 3600UL 2279

Sensors,switchgear ■ ■

Protection types n Zone 2This protection type comprises several types of protection

Slightly simplified application of the other Zone-2 protection types – "n" stands for "non-igniting"

EN 50 0211)

IEC 60 079-15Programmable controllers ■ ■

1) as of 2007: EN 60079-15*) Label



Dusts – Types of protection Application in Zone

Type of protection Label Basic principle Standard Examples 20 21 22

Pressurized enclosure pD The penetration of a surrounding atmo-sphere into the enclosure of electrical equipment is prevented in that a protective gas (air, inert gas or other suitable gas) is kept within the enclosure at a pressure higher than the surrounding atmosphere

EN 50281IEC 61241

Equipment where sparks, arcs or hot com-ponents occur in normal oper-ation

■ ■ ■

Molding mD Parts which could ignite an explosive atmo-sphere through sparks or warming-up are potted in a casting compound such that the explosive atmosphere cannot ignite. This is achieved by surrounding the components on all sides by a casting compound which is resistant to physical (in particular electrical, thermal and mechanical) and chemical in-fluences

EN 50281IEC 61241

Large machines, slipring or col-lector motors, switchgear and control cabinets ■ ■ ■

Protection by enclosure

tD The enclosure is sealed so tight that no combustible dust can penetrate into it. The surface temperature of the external enclo-sure is limited.

EN 50281IEC 61241

Measuring and monitoring sys-tems

■ ■ ■

Intrinsic safety iaD, ibD Current and voltage are limited such that intrinsic safety is guaranteed. No sparks or thermal effects can ignite a dust/air mix-ture.

EN 50281IEC 61241

Sensors and actuators ■ ■ ■



Classification of explosion-proof equipment

Explosion groups

In the explosion groups, a distinction is first made between equipment of Group 1 and of Group II:

Electrical equipment of Group I is used for mines subject to fire-damp.

A further division into explosion groups is made for the electri-cal equipment of Group II. The division depends on the spark ignition capability through a gap of defined width and length (according to EN 60079-14).

Electrical equipment with approval for explosion group IIC may also be used in explosion groups IIA and IIB.

Determination of explosion group

A gas is present both inside and outside a flame-proof enclo-sure. The gas inside the explosion chamber is ignited.

Result: If an ignition inside the explosion chamber is not transferred through the gap of defined width to the outside, the explosion group has been determined.

Explosion group Use

Group I Electrical equipment for mines subject to fire-damp.==> fire-damp protection EEx...I

Group II Electrical equipment for all other areas subject to explosion hazard==> explosion protection EEx...II

Explosion group

Gap width limits for flameproof enclosure1)

Degree of hazard

Equipment requirements

IIA > 0.9 mm

IIB 0.5 mm bis 0.9 mm

IIC < 0.5 mm

Explosion chamber

Gap width1)

Potentially explosive atmosphere

Gap length

1) The gap width limit is the width between two 25-mm long, parallel flange surfaces of an explosion chamber

low low

high high



Temperature classes

The ignition temperature of flammable gases or a flammable liquid is the lowest temperature of a heated surface at which the gas/air or vapor/air mixture ignites.

Thus the highest surface temperature of any equipment must always be less than the ignition temperature of the surround-ing atmosphere.

Temperature classes T1 to T6 have been introduced for electri-cal equipment of Explosion Group II. Equipment is assigned to each temperature class according to its maximum surface temperature.

Equipment that corresponds to a higher temperature class can also be used for applications with a lower temperature class.

Flammable gases and vapors are assigned to the relevant tem-perature class according to ignition temperature.

Classification of gases and vapors into explosion groups and temperature classes

Temperature class

Maximum upper surface temper-ature of the equipment

Ignition temperatures of combustible substances

T1 450 °C > 450 °C

T2 300 °C > 300 °C

T3 200 °C > 200 °C

T4 135 °C > 135 °C

T5 100 °C > 100 °C

T6 85 °C > 85 °C

Explosions-group

Temperatur class

T1 T2 T3 T4 T5 T6

I Methane

II A AcetoneEthaneEthylacetateAmmoniaBenzene (pure)Ethanoic acidCarbon monoxideCarbon oxideMethaneMethanolPropaneToluol

Ethyl alcoholi-amyl acetaten-butanen-butylalcohol

PetrolDiesel fuelAircraft fuelHeating oilsn-hexane

AcetylaldehydeEthylether

II B City gas (illuminating gas)

Ethylene

II C Hydrogen Acetylene Carbon bisulfide


16 Installing and operating electrical systems in potentially explosive atmospheres

Installing and operating electrical systems in potentially explosive atmospheres

Standards

The installation and erection regulations specified in EN 60079-14 apply, as well as national regulations.

Installation

Three installation systems are used for electrical systems in ar-eas subject to explosion hazard (see table).

Service and maintenance

Regular servicing is required to maintain the safety of electrical systems in areas subject to explosion hazard.

Some of the most important safety measures are:

■ Carrying out work on live electrical systems and equipment is prohibited in areas subject to explosion hazard. Work on intrinsically-safe circuits is a permissible exception.

■ In areas subject to explosion hazard, grounding or short-cir-cuiting is only permissible if there is no danger of explo-sion.

■ In the case of all work carried out in areas subject to explo-sion hazard, there must be no possibility of ignitable sparks or excessively hot surfaces occurring that cause an explo-sion in conjunction with a potentially explosive atmosphere

Operators must observe the following important principles in service and maintenance work:

■ Maintenance of the proper state of the system

■ Continuous monitoring of the electrical system

■ Undelayed execution of the necessarymaintenance measures

■ Proper operation of system

■ Cessation of operations in the case ofunrectifiable faults that can constitute ahazard to personnel


Installing and operating electrical systems in potentially explosive atmospheres 17

Installation systems in areas subject to explosion hazard

Obligations of the manufacturer, installer and owner

Cable systemswith indirect cable inlet

Cable systemswith direct cable inlet

Piping systems

The cables are inserted into the connection area of the protection type "Increased safety" via cable inlets and connected to the termi-nals. The terminals also have protection type "In-creased safety".

The cables are inserted directly into the con-nection area of the device. Only cable glands especially certified for this may be used.

The electrical cables are fed into the closed metal piping as single cores. The piping is connected to the housing using glands and provided with a seal at every inlet point. The entire piping system is flameproof in design.The piping system is also known as a conduit system.

Manufacturer Installer Plant owner

Tasks

Development of electrical equipment for use in hazardous areas.

Selection and installation of electrical equip-ment according to application.

Safe operation of the plant.

Obligations

Observation of general and special design re-quirements and technological state-of-the-art. Request for testing by an independent insti-tution if specified by the associated standard.Passing on of all approvals and manufacturer declarations to the user.Manufacture of each electrical unit according to the test documents and test specimens.

Selection and installation with consideration of the installation requirements and the application.If the installer is not the owner at the same time, the installer is obliged on request of the owner to provide an installation certificate.This confirms that the electrical equipment corresponds to the requirements.If such a certificate is available, additional testing by the owner prior to the first startup is no longer required.

Responsibility for safety of the plant.Zone assignment according to explosion hazards.Testing of correct, safe state of plant:■ Prior to first startup■ At certain intervals

Correct operation of the electrical equipment.Every explosion which may be caused by op-eration of the plant must be reported to the supervisory authority.


18 Installing and operating electrical systems in potentially explosive atmospheres

Intrinsic safety

The intrinsic safety of a circuit is achieved through limitation of the current and voltage. This property limits the protection type "Intrinsic safety" to circuits with relatively low power. Applications include e.g. measuring and control technology.

The basis for the protection type "Intrinsic safety" is that a cer-tain minimum ignition energy is required to ignite a potential-ly explosive atmosphere. In an intrinsically-safe circuit, no sparks or thermal effects occur in operation or in the event of a fault that ignite a potentially explosive atmosphere.

Categories of intrinsically-safe equipment

Intrinsically-safe electrical equipment and intrinsically-safe parts of associated equipment are divided into categories (safety levels). The safety levels depend on safety require-ments in designing the equipment.

Isolating amplifiers and isolating transformers

Isolating amplifiers and isolating transformers between the in-trinsically-safe and non-intrinsically-safe circuits of the equip-ment provide the voltage and current limiting necessary for use in hazardous areas.

The isolating amplifiers and isolating transformers can be de-signed as separate equipment or integrated in the modules.

Terms and definitions for intrinsic safety

Safety level of intrinsically-safe equipment

Terms Definitions

Intrinsically-safe circuit

A circuit in which no spark and no thermal ef-fect can cause the ignition of a potentially ex-plosive atmosphere.

Intrinsically- safe electrical equipment

All circuits are intrinsically safe.

Voltage and current in the intrinsically-safe circuit are low enough that a short-circuit, interruption or short-circuit to ground will not ignite the potentially explosive atmosphere.

Intrinsically-safe electrical equipment is suit-able for operation direct in the area subject to explosion hazard.

Typical designation: EEx ib IIC

Associated electrical equipment

At least one circuit is intrinsically safe.

Actuators and sensors connected to this intrinsically-safe circuit can be located in the area subject to explosion hazard.

However, the associated electrical equipment must not be located in the area subject to explosion hazard without further protection types.

In the designation of associated electrical equipment, the type of protection is placed in brackets.

Typical designation: [EEx ib] IIC

Minimum ignition energy

The minimum ignition energy of a gas and a vapor/air mixture is the least possible electri-cal energy discharged by a capacitor that can ignite the most ignitable mixture of a gas or a vapor with air at atmospheric pressure and 20°C.

Safety levell Description Installation of the equipment

ia The intrinsically-safe electrical equipment must not cause an ignition:■ During normal operation

■ On the occurrence of a single fault

■ On the occurrence of a combination of faults

Up to Zone 0

ib The intrinsically-safe electrical equipment must not cause an ignition■ During normal operation

■ On the occurrence of a single fault

Zone 2, Zone 1


Ex protection in North America: Comparison of zones/divisions 19

Ex protection in North America:Comparison of zones/divisions

The basic principles of explosion protection are identical all over the world. However, techniques and systems have been developed in North America in the area of explosion protection that differ significantly from those of the IEC (International Electrotechnical Commission).

The difference to IEC technology include subdivision of the ar-eas subject to explosion hazard, the design of equipment, and the installation of electrical systems.

Classification of areas subject to explosion hazard

Areas subject to explosion hazard are termed "hazardous (clas-sified) locations" in North America. In the US, they are defined in Sections 500 and 505 of the National Electrical Code (NEC), and in Canada they are defined in Section 18 and Annex J of the Canadian Electrical Code (CEC). They encompass areas in which flammable gases, vapors, or mist (Class I), dusts (Class II) or fibers and threads (Class III) can be present in hazardous quantities.

The areas subject to explosion hazard are traditionally subdi-vided into Division 1 and Division 2 according to the frequency and duration of their occurrence.

In 1996, the US introduced the IEC classification system addi-tionally to the existing system for Class I. This change was made by Article 505 of the NEC, enabling users to select the optimal system from a technical and economic point of view.

The IEC Zone concept was also introduced in Canada (CEC Edi-tion 1988). Since then, all newly installed systems there must be classified according to this system.

In the traditional North-American classification system, poten-tially explosive gases, vapors, and mist of Class I are arranged in Gas Groups A, B, C and D, and flammable dusts of Class II are arranged in Groups E, F and G.

The letter A here indicates the most hazardous gas group, while according to IEC and the new classification in accor-dance with Article 505, Group C is the most hazardous gas group.

In Canada, it is possible to use both gas group systems in zone classification.

Determination of the maximum surface temperature in accor-dance with Article 505 in the NEC takes place in agreement with IEC in six temperature classes T1 to T6, with an additional subdivision into temperature sub-classes in the division sys-tem. The existing system of temperature classes has not been changed following the CEC 1998.

Degrees of protection provided by enclosures

Just as the IP degrees of protection have been defined in accor-dance with IEC 60529, the US has Standard Publ. No. 250 of NEMA (National Electrical Manufacturing Association) that deals with the degree of protection of housings.

These degrees of protection cannot be equated exactly with those of the IEC since NEMA takes account of additional envi-ronmental influences (e.g. coolants, cutting coolants, corro-sion, icing, hail). The following table is therefore intended as a non-binding guideline.

Comparison of degrees of protection according to NEMA and IEC

Note: Since the degree of protection requirements of NEMA corre-spond to, or are higher than, the IP degrees of protection of IEC, the table cannot be used to convert the IEC degrees of protection into corresponding NEMA degrees of protection!

Degrees of protection according to NEMA

egrees of protection accor-ding to IEC

1 IP10

2 IP11

3 IP54

3R IP14

3S IP54

4 and 4X IP56

5 IP52

6 and 6P IP67

12 and 12K IP52

13 IP54


20 Ex protection in North America: Comparison of zones/divisions

Ex protection in North America:Comparison of zones/divisions

Classification of areas subject to explosion hazard

Gases, vapors, or mistClassification Class I

SDustClassification Class II

Fibers and threadsClassification Class III

NEC 500-5CEC J18-004

NEC 505-7CEC 18-006

NEC 500-6CEC 18-008

NEC 500-7CEC 18-010

Division 1Areas in which hazardous con-centrations of flammable gases, vapors, or mist are present con-tinuously or occasionally under normal operating conditions.

Zone 0Areas in which hazardous con-centrations of flammable gases, vapors, or mist are present con-tinuously or over long periods under normal operating condi-tions.

Division 1Areas in which hazardous con-centrations of flammable dusts are present continuously or occa-sionally under normal operating conditions.

Division 1Areas in which hazardous con-centrations of flammable fibers and threads are present continu-ously or occasionally under nor-mal operating conditions.

Zone 1Areas in which hazardous con-centrations of flammable gases, vapors, or mist are present occa-sionally under normal operating conditions.

Division 2Areas in which hazardous con-centrations of flammable gases, vapors, or mist are not expected under normal operating condi-tions.

Zone 2Areas in which hazardous con-centrations of flammable gases, vapors, or mist are not expected under normal operating condi-tions.

Division 2Areas in which hazardous con-centrations of flammable dusts are not expected under normal operating conditions

Division 2Areas in which hazardous con-centrations of flammable fibers and threads are not expected under normal operating condi-tions

Class I Groups Class II Groups Class III

NEC 500-3CEC J18-050

NEC 505-7CEC J18-050

NEC 500-3CEC J18-050

Division 1 and 2A (acetylene)B (hydrogen)C (ethylene)D (propane)

Zone 0, 1 and 2IIC (acetylene + hydrogen)

IIB (ethylene)IIA (propane)

Division 1 and 2E (metal)F (coal)G (grain)

Division 1 and 2None

Class I Temperature classes

Division 1 and 2 Zone 0, 1 and 2

Class II Temperature classesDivision 1 and 2

Class III Temperature classesDivision 1 and 2

T1 (≤450 °C) T1 T1 None

T2 (≤300 °C) T2 T2

T2A (≤280 °C)T2B (≤260 °C)T2C (≤230 °C) T2D (≤215 °C)

– T2A, T2B, T2C, T2D

T3 (≤200 °C) T3 T3

T3A (≤180 °C)T3B (≤165 °C)T3C (≤160 °C)

– T3A, T3B, T3C

T4 (≤135 °C) T4 T4

T4A (≤120 °C) – T4A

T5 (≤100 °C) T5 T5

T6 (≤85 °C) T6 T6


Ex protection in North America: Comparison of zones/divisions 21

Installation regulations

Electrical equipment and systems for use in hazardous loca-tions are covered by the National Electrical Code (NEC) in the US, and the Canadian Electrical Code (CEC) in Canada. These assume the character of installation regulations for electrical systems in all areas and they refer to a number of further stan-dards from other institutions that contain regulations for the installation and construction of suitable equipment.

The installation methods for the NEC's Zone concept largely correspond to those of the traditional Class/Division system. A new stipulation in the NEC 1996, is the use of metal-clad (MC) cables, in addition to rigid conduits and mineral-insulated ca-bles of Type MI in Class I, Division 1 or Zone 1.

Building regulations

The regulations of the National Electrical Code and the Cana-dian Electrical Code specify which equipment or types of pro-tection can be used in the individual areas subject to explosion hazard.

In North America, different standards and regulations apply for the building and testing of explosion-protected electrical systems and equipment. In the US, these are primarily the standards of Underwriters Laboratories Inc. (UL), Factory Mu-tual Research Corporation (FM) and the International Society for Measurement and Control (ISA). In Canada, it is the Cana-dian Standards Association (CSA).

Certification and designation

In the US and Canada, electrical equipment and resources in workplaces subject to explosion hazard generally require ap-proval. Electrical equipment that cannot ignite the potentially explosive atmosphere in which it is used by virtue of its design or special properties, is an exception to this rule. The compe-tent authority decides if approval is required.

Equipment that has been developed and manufactured for use in hazardous areas is tested and approved in the US and Cana-da by nationally recognized test centers. In the US, these in-clude the test centers of the Underwriters Laboratories or Fac-tory Mutual, and in Canada, the Canadian Standards Associa-tion.

Any information relating to explosion protection must be shown on the marking of the equipment, along with informa-tion such as manufacturer, model, serial number, and electri-cal specifications. The requirements for this are specified in the NEC, the CECl, and in the relevant construction regulations of the test centers.

Class I, II & III, Division 1 and 2

Approved electrical equipment for Class I, Class II and Class III, Division 1 and 2 must be marked to show the following infor-mation:

1. Class(es), division(s)(optional except for Division 2)

2. Gas/dust group(s)3. Operating temperature or temperature class

(optional for T5 and T6)

Examples: Class I Division 1 Groups C D T6

Class I, Zone 0, 1 and 2

In the case of equipment for use in Class I, Zone 0, Zone 1 or Zone 2, a distinction is made between "Division Equipment" and "Zone Equipment".

■ Division Equipment: Equipment approved for Class I, Division 1 and/or Class I, Di-vision 2, can be labeled with the following information:

1. Class I, Zone 1 or Class I, Zone 22. Gas group(s) IIA, IIB or IIC3. Temperature class

Example: Class I Zone 1 IIC T4

■ Zone Equipment: Equipment that corresponds to one or more protection types in accordance with Article 505 of the NEC and Section 18 of the CEC must be labeled as follows:

1. Class (optional in Canada)2. Zone (optional in Kanada)3. Symbol AEx (USA) or Ex or EEx (Canada)4. Protection type(s) used5. Electrical equipment Group II or

gas group(s) IIA, IIB or IIC6. Temperature class

Example: Class I Zone 0 AEx ia IIC T6


22 Safety parameters

Safety parametersCombustible gases and vapors

Substance designation Ignition temperature °C Temperature class Explosion group

1,2-dichloroethane 440 T2 II A

Acetaldehyde 140 T4 II A

Acetone 540 T1 II A

Acetylene 305 T2 II C 3)

Ammonium chloride 630 T1 II A

Gasoline,initial boiling point < 135°C

220 ... 300 T3 II A

Benzene (pure) 555 T1 II A

Cyclohexanone 430 T2 II A

Diesel fuels (DIN 51601) 220 ... 300 T3 II A

Jet fuel 220 ... 300 T3 II A

Ethanoic acid 485 T1 II A

Ethanoic acid anhydride 330 T2 II A

Ethane 515 T1 II A

Ethyl acetate 460 T1 II A

Ethyl alcohol 425 T2 II A / II B

Ethyl chloride 510 T1 II A

Ethylene 425 T2 II B

Ethylene oxide 440 (self-decomposing) T2 II B

Ethyl ether 170 T4 II B

Ethylene glycol 235 T3 II B

Heating oil L (DIN 51603) 220 ... 300 T3 II A

Heating oils M and S (DIN 51603) 220 ... 300 T3 II A

i-amyl acetate 380 T2 II A

Carbon monoxide 605 T1 II A / II B

Methane 595 (650) T1 II A

Methanol 455 T1 II A

Methyl chloride 625 T1 II A

Naphthalene 540 T1 II A

n-butane 365 T2 II A

n-butyl alcohol 340 T2 II A

n-hexane 240 T3 II A

n-propyl alcohol 405 T2 – *)

Oleic acid 360 (self-decomposing) T2 – *)

Phenol 595 T1 II A

Propane 470 T1 II A

Carbon bisulfide 95 T6 II C 1)

Hydrogen sulfide 270 T3 II B

Special gasolines, Initial boiling point < 135°C

200 ... 300 T3 II A

City gas (illuminating gas) 560 T1 II B

Tetralin (tetrahydronaphtalene) 425 T2 – *)

Toluol 535 T1 II A

Hydrogen 560 T1 II C 2)

Extract from the tables "Safety Ratings of Flammable Gases and Vapors" by K. Nabert and G. Schoen - (Edition 6)*) The explosion group for this material has not yet been determined.1) Also explosion group II B + CS22) Also explosion group II B + H23) Also explosion group II B + C2 H2


Safety parameters 23

Combustible dusts

Ignition and glow temperatures of the dusts of natural products

Substance designation Ignition temperature °C Glow temperature °C

Cotton 560 350

Wood dust 400 300

Fodder concentrate 520 295

Grain 420 290

Soya 500 245

Tobacco 450 300

Starch 440 290

Ignition and glow temperatures of the dusts of chemical products

Substance designation Ignition temperature °C Glow temperature °C

Polyester 560 –

Rubber 570 –

Washing agent 330 –

Polyethylene 360 –

Polyvinyl acetate 500 340

Aluminium 530 280

Magnesium 610 410

Sulfur 280 280


24 Approval and testing centers

Approval and testing centers

Country Approval/testing center

Australien International Testing and Certification Services (ITACS)4-6 Second Street, Bowden South Australia 5007Tel: +61-8-8346-8680, Fax: +61-8-8346-7072E-mail: [email protected]: www.itacslab.com

SAI Global Assurance Services286 Sussex Street, GPO Box 5420, Sydney NSW 2001Tel: +61-2-8206-6060, Fax: +61-2-8206-6061E-mail: [email protected]: www.sai-global.com

Simtars Head Office2 Smith Street, Redbank Qld 4301, PO Box 467, Goodna Qld 4300, AustraliaTel: +61-7-3810-6333, Fax: +61-7-3810-6363E-Mail: [email protected]: www.nrm.qld.gov.au/simtars/index.html

TestSafe Australia919 Londonderry Road, Londonderry NSW 2753P.O.Box 592, Richmond NSW 2753Tel: +61-2-4724-4900, Fax: +61-2-4724-4999E-mail: [email protected]: www.testsafe.com.au

Bosnia-Herzegovina

Institut za standarde, mjeriteljstvo i intelektualno vlasnižtvo Hamdije Cemerlica 2/7, BiH - 71000 SarajevoTel. +387-(0)33-65 27 65FAX +387-(0)33-652757E-Mail: [email protected]: www.basmp.gov.ba

Brazil CEPELCaixa Postal 68.007, CEP: 21.944-970, Rio de Janeiro, BrazilTel: +55-21-2598-6458, Fax: +55-21-2280-3687E-Mail: [email protected]

China Shanghai Institute of Process Automation Instrumentation (SIPAI)103 Cao Bao Road, Shanghai 200233, ChinaTel: +86-21-64368180, Fax: +86-21-64333566E-mail: [email protected]: www.sipai.com

Denmark UL Internationales Demko A/SLyskaer 8, P.O.Box 514, DK-2730 HerlevTel: +45-44-85-65-65, Fax: +45-44-85-65-00E-mail: [email protected]: www.ul-europe.com

Germany DMT - Gas & Fire DivisionAm Technologiepark 1, D-45307 EssenTel: +49-201-172-01, Fax: +49-201-172-1462E-mail: [email protected]: www.dmt.de

FSA - Forschungsgesellschaft f. angewandte Systemsicherheit u. Arbeitsmedizin mbHDynamostraße 7-11, D-68165 MannheimTel: +49-621-4456-1555, Fax: +49-621-4456-3645E-mail: [email protected] Internet: www.fsa.de

IBExU Institut f. Sicherheitstechnik GmbH Fuchsmühlenweg 7, D-09599 FreibergTel: +49-3731-3805-0, Fax: +49-3731-23650E-mail: [email protected]: www.ibexu.de

Physikalisch-Technische Bundesanstalt (PTB)Bundesallee 100, D-38116 BraunschweigTel: +49-531-592-0, Fax: +49-531-592-9292Abbestraße 2-12, D-10587 BerlinTel: +49-30-3481-1, Fax: +49-30-3481-490E-mail: [email protected]: www.ptb.de

TÜV Hannover/Sachsen-Anhalt e.V.Am Tüv 1, D-30519 HannoverTel: +49-511-986-0, Fax: +49-511-986-1237E-mail: [email protected]: www.tuev-nord.de


Germany (continued)

TÜV Nord e.V. Große Bahnstraße 31, D-22525 HamburgTel: +49-40-8557-0, Fax: +49-40-8557-2295E-mail: [email protected]: www.tuev-nord.de

Finland VTT Technical Research Centre of FinlandP.O.Box 1000, FIN - 02044 VTTTel: +358 20 722 111, Fax: +358 20 722 7001E-mail: [email protected]: www.vtt.fi

France INERIS HeadquarterParc Technologique ALATA BP 2, F-60550 Verneuil en HaletteTel: +33-3- 44 55 66 77, Fax: +33-3-44 55 66 99E-mail: [email protected]: www.ineris.fr

LCIE - Laboratoire Central des Industries Électriques 33 av du Général Leclerc, F-92260 Fontenay-aux-RosesTel: +33-1-40 95 60 60, Fax: +33-1-40 95 5529E-mail: [email protected]: www.lcie.com

UK Baseefa (2001) Ltd, Health and Safety Laboratory SiteHarpur Hill, GB - Buxton Derbyshire SK17 9JNTel: +44-1298-28255, Fax: +44-1298-28216E-mail: [email protected]: www.baseefa.com

ERA Technology LtdCleeve Road, GB -Leatherhead Surrey KT22 7SATel: +44-1372-367-000, Fax: +44-1372-367-099E-mail: [email protected]: www.era.co.uk

SIRA Head OfficeSouth Hill, GB - Chiselhurst Kent BR7 5EHTel: +44-20-846872636, E-mail: [email protected]: www.sira.co.uk

SIRA Certification Service (SCS)Rake Lane, Eccleston Chester England CH4 9JNTel: +44 (0) 1244 670 900, Fax: +44 (0) 1244 681 330E-mail: [email protected]: www.siraservices.com

SIRA Test and Certification LtdRake Lane Eccleston, GB - Chester CH4 9JNTel: +44-1244-670-900, Fax: +44-1244-681-330E-mail: [email protected]: www.siraservices.com

Italy Centro Elettrotecnico Sperimentale Italiano (CESI)Via Rubattino 54, I-20134 MilanoTel: +39-02 21251, Fax: +39-02 2125 5440Internet: www.cesi.it

Japan The Technical Institution of Industrial Safety (TIIS) Kiyose Test House1-4-6 Umezono Kiyose, Tokyo 204-0024 JapanTel: +81-424-91-4519, Fax: +81-424-91-4846Internet: www.ankyo.or.jp

The Technical Institution of Industrial Safety (TIIS) Headquarter837-1 Higashi-Nakahara, Kamihirose Syama-shi, Saitama, 350-1321 JapanTel: +81-42-955-9901, Fax: +81-42-955-9902Internet: www.ankyo.or.jp

Canada CANMET 555 Booth, Ottawa, Ontario K1A 0G1Tel: (613) 947-3410, Fax: (613) 943-0573

CSA International178 Rexdale Boulevard, Toronto, Ontario, CANADA, M9W 1R3Tel: +416-747-4000, Fax: +416-747-4149E-mail: [email protected]: www.csa-international.org


Approval and testing centers 25


Korea Korea Industrial Safety Corp. (KISCO)34-4 Kusa-dong, Poopyoung-gu, Inchon 403-120, The Republic of KoreaTel: +82 32 5100 865, Fax: +82 32 518 6483-4

Croatia ZIK - Zavod za Ispitivanje Kvalitete Robe d.d.Ljudevita Gaja 17/3, 10000 Zagreb, CroatiaTel: +385 (0) 1 4806 777, Fax: +385 (0) 1 4806 700E-Mail:[email protected]:www.zik.hr

Netherlands KEMA HeadofficeP.O.Box 9035, NL-6800 ET Arnhem, Utrechtseweg 310, NL-6812 AR ArnhemTel: +31-26 3 56 91 11, Fax: +31-26 3 89 24 77E-mail: [email protected]: www.kema.nl

Norway Nemko AS (Head Office)PO Box 48, Blindern, Gaustadalleen 30, N-0314 OsloTel: +47-22 96 06 00, Fax: +47-22 96 06 01E-mail: [email protected] Internet: www.nemko.de

Austria TÜV ÖsterreichKrugerstraße 16, A-1015 WienTel: +43-1-514-07, Fax: +43-1-514-07-6005E-mail: [email protected]: www.tuev.at

Sweden Swedish National Testing and Research Institute (SP), Brinellgatan 4Box 857, S-501 15 BorasTel: +46-33-16-5000, Fax: +46-33-13-5502E-mail: [email protected] Internet: www.sp.se/eng

Switzerland Eidgenössisches Starkstrominspektorat (ESTI)Luppmenstraße 1, CH-8320 FehraltorfTel: +41-44-956-1212, Fax: +41-44-956-1222E-mail: [email protected] Internet: www.esti.ch

ElectrosuisseLuppmenstraße 1, CH-8320 FehraltorfTel: +41-1-956-1111, Fax: +41-1-956-1122E-mail: [email protected]: www.electrosuisse.ch


Slovakia EVPU a.s., SKTC 101Trencianska 19, SK - 01851 Nova Dubnica (Slovakia)Tel: +421/42/44 09 102, Fax: +421/42/44 34 252E-mail: [email protected]: www.evpu.sk

Slowenia SIQ - Slovenian Institute of Quality and MetrologyMr Igor LikarTrzaska cesta 2, SI - 1000 LjubljanaTel: +386-1-4778-100, Fax: +386-1-4778-444E-mail: [email protected]: www.siq.si

Spain Laboratorio Official Jose Maria Madariaga (LOM)Calle Alenzaa 1-2, E - 28003 MadridTel: +34 913367009, Fax: +34 914419933E-mail: [email protected] Internet: www.lom.upm.es

South Africa South African Bureau for Standards (SABS)1 Dr. Lategan Road; Groenkloof, Private Bag X191, Pretoria 0001, South AfricaTel: +27-12-428-7911/6405, Fax: +27-12-344-1568E-mail: [email protected]: www.sabs.co.za

Czech Republik Physical-technical testing institute, Ostrava-RadvanicePikartska 7, CZ - 71607 Ostrava-RadvaniceTel: +420 59 62 327 15, Fax: +420 59 62 326 72E-mail: [email protected]: www.ftzu.cz

Ukraine Testing Certification Center of Explosion protected and mining Electrical Epuipment50-ty Gvardeysky, divizii str., 17, Ukraine, 83052 DonetskTel: +38-(0622)-941243, Fax: +38-(0622)-3450417E-mail: [email protected]: www.tccexec.org

Hungary Prüfstelle für Ex-geschützte Elektrische Betriebsmittel, BKIMikoviny Sámuel u. 2-4, H - 1300 Budapest, Pf. 115Tel: (361) 368 9697, 388-9101, Fax: (361) 250 1720E-mail: [email protected]: www.bki.hu

USA Northbrook Division, Illinois, Corporate Headquarters333 Pfingsten Road, Northbrook, IL 60062-2096; USATel: +1-847-272-8800, Fax: +1-847-272-8129E-mail: [email protected]: www.ul.com


26 SIMATIC ET 200 for hazardous areas

Productrange of SIMATIC ET 200 for hazardous areas

For areas subject to explosion hazard, Siemens develops forward-looking distributed solutions in automation engineering. SIMATIC ET 200 systems can be integrated simply and quickly via PROFIBUS into any controller.

PROFIBUS has become established as the standard bus in the field, even in hazardous areas. The solution remains flexible and is also open to other manufacturers through this open, in-tegrated communication.

The international standardization of the PROFIBUS additionally ensures the user that his investments, which are frequently comprehensive and for many years, are future-oriented.

PROFIBUS offers integrated communication in the process in-dustry from inbound through mainstream to outbound. Pa-rameterization with SIMATIC STEP 7 enables optimal integra-tion into the SIMATIC PCS 7 process control system. The rug-ged design offers the highest possible level of reliability. The many and varied diagnostics facilities guarantee fault-free use.

SIMATIC ET 200S

the multitalent with a comprehensive range of functions

■ Bit-modular design with multi-conductor connection.

■ Multifunctional through wide range of modules, e.g. safety engineering, distributed intelligence and IQ-Sense sensor modules.

■ Use in hazardous area is (Zone 2).

■ Also available as expandable block version with integral DI/DO: SIMATIC ET 200S COMPACT.

SIMATIC ET 200M the multi-channel S7-300

■ Modular design with standard modules from the SIMATIC S7-300 range, redundant design also possible

■ Failsafe I/O modules

■ Use in hazardous areas up to Zone 2 (Ex i), sensors and actuators up to Zone 1

■ High plant availability through redundancy, hot swapping and configuration in run (CiR)

SIMATIC ET 200iSPthe intrinsically-safe version for hazardous areas

■ Modular design, also redundant design possible.

■ Rugged and intrinsically-safe design

■ Use in hazardous areas up to Zone 1/21 (Ex i), sensors and actuators can even be in Zone 0/20

■ High plant availability through redundancy, hot swapping and configuration in run (CiR)


SIMATIC ET 200 for hazardous areas 27

The distributed I/O systems ET 200S, ET 200M and ET 200iSP can also be used in areas subject to gas and dust ex-plosion hazards, e.g. in the chemical, food and tobacco or pharmaceutical industries, or on drilling platforms.

The ET 200 systems can be used in different zones – either in Zones 2 and 1 in the case of gaseous atmospheres or in Zones 22 and 21 in the case of dust atmospheres. The sensors and actuators linked to the I/Os can even be in Zone 0/20.

A manufacturer's note is necessary for installation in Zone 2/22. A certification must be procured for installation in Zone 1/11.

Data communication takes place as usual over PROFIBUS DP. If communication is continued beyond the potentially explosive atmosphere, i.e. beyond Zone 1 or 21, the PROFIBUS DP is made intrinsically safe by intermediate connection of a field-bus isolating transformer. This limits the ignition energy to the permissible level and routes it to the hazardous area with in-trinsic safety.

ET 200 in hazardous gas and dust atmospheres

1) Dusty atmospheres: Installation of components always in an enclosure with IP6x degree of protection.2) With DC 10A Standard Power Supply3) Also complies with FM/UL to Class I Division 2, connected sensors/actuators even up to Class I Division 1

012Zone 2 Zone 1 Zone 0

Class I Zone 2FM/UL

ATEX

Class I Zone 1 Class I Zone 0

ATEXDUST

ET 200M

S7-400

ET 200S

ET 200iSP

SITRANS F SITRANS P

Industrial Ethernet

PROFIBUS DP

PROFIBUS PA

Zone 22 Zone 21 Zone 20

Class II Zone 2 Class II Zone 1 Class II Zone 0FM/UL

Control system

1)

1)

1)

1)

3)

2)

1)

FieldbusIsolating Transformer

Hazardous area

Actuators/sensors

Actuators/sensors

Actuators/sensors

DP/PA-Link

Actuators/sensors

Product range of SIMATIC ET 200 for hazardous areas



SIMATIC ET 200iSPthe intrinsically-safe version for hazardous areas

ET 200iSP in redundant configuration

ET 200iSP can be used in hazardous areas with a gas or dust atmosphere:

■ The ET 200iSP station can be installed in Zones 1, 21 and 2, 22

■ The connected sensors and actuators can also be lo-cated in Zones 0, 20.

Communications between the field devices and the process control system or automation system is over PROFIBUS DP. This enormously reduces the cabling overhead. The signal routing cubicles common nowadays as well as the required subdistrib-utors and Ex isolating amplifiers for the individual signals are omitted.

ET 200iSP provides a high plant availability through

■ Configuration in run (CiR). It is possible to - add stations,

- expand stations by modules, and

- change module parameters.

■ Hot swappingThe backplane bus integrated in the terminal modules en-ables permanent wiring and thus simple and reliable re-placement during operation. Hot swapping of the power supply is possible without a fire certificate.

■ RedundancyPROFIBUS and/or the power supply can also be provided with a redundant design.

HART-Support

ET 200iSP offers the HART protocol for connecting process de-vices with HART capability. These HART modules also support the transfer of auxiliary variables. Apart from the actual mea-sured value, up to 4 IEEE variables can be transferred in the process image. By means of a routing function, a central sta-tion can access the HART process devices transparently over PROFIBUS DP. A higher-level control system can therefore per-form central data administration.

The process devices are connected by means of a 4 to 20 mA analog signal. Further device information is transferred over a modulated signal:

■ Parameters that are specified by a central engineering sta-tion (routing)

■ Diagnostic data that are read by the engineering stationn

This principle is called HART (Highway Addressable Remote Transducer). The majority of process instruments, e.g. for tem-perature, fill-level, pressure or flowrate measurement have HART connections.

Powerful diagnostics with SIMATIC PCS 7

With SIMATIC ET 200iSP, numerous items of diagnostic infor-mation are generated when internal and external faults occur, e.g. on wire-break or short-circuit.

The HART status of the connected HART field devices such as maintenance and additional information is mirrored in the di-agnostics and signaled to the higher-level control system. Standard diagnostic drivers are available for SIMATIC PCS 7 for the diagnostic messages. These drivers prepare all the relevant signals for the higher-level operator system of PCS 7.

The detected faults are transferred quickly to the higher-level systems, e.g. a PCS7 maintenance station, and support online diagnostics from a central point at any time.

CENELEC II 2 G (1) GD EEx d e [ia/ib] IIC/IIB T4

FM IS, Class I Zone 1, Aex ib [ia] IIC, T4Class I, II, III Division 2Groups A, B, C, D, E, F, G, T4

Temperatur -20 °C ... +70 °C


SIMATIC ET 200 for hazardous areas 29

SIMATIC ET 200Sthe multitalent with the comprehensive range of modules

ET 200S with I/O modules

SIMATIC ET 200S is the multifunction and bit-modular I/O system with IP20 degree of protection which permits exact adaptation to the automation task. As a result of its rugged design, it can also be used with increased mechanical stress.

Interfacing to the PROFIBUS and/or PROFINET bus systems is by means of various interface modules. Such modules with inte-gral CPU transfer the computing performance of an S7-300 CPU directly to the I/O device. They therefore offload the cen-tral PLC, and permit fast responses to time-critical signals. New high feature interface modules, fast I/O modules, isochronous mode and greatly accelerated internal data transport increase the performance of the ET 200S. The ET 200S can then also be used with high-speed controllers.

Distributed automation solutions not only cover digital and analog signals, but frequently also require technological func-tions or a pneumatics connection. The bit-modular ET 200S of-fers a comprehensive range of modules for solving versatile tasks:

■ Technology modules are available e.g. for counting and po-sitioning tasks, for cam control or for closed-loop control tasks.

■ Pneumatics connection using modules from Bürkert.

■ IQ-Sense sensor modules allow the connection of intelli-gent sensors such as Sonar-BEROs.

■ Failsafe I/O modules permit integration into safety-relevant systems with SIMATIC Safety Integrated.

Diagnostics functions and hot swapping of modules increase plant availability:

■ Comprehensive diagnostics messages indicate the module status and also provide channel-granular information.

■ Hot swapping of electronics modules is possible without tools. The SIMATIC ET 200S continues to operate while hot swapping is being carried out, and the application remains functional.

SIMATIC ET 200S COMPACT –block I/O featuring bit-modular expansion

The IM 151-1 COMPACT interface module supplements the fa-miliar module range of the proven ET 200S and enables use as block I/O. It combines frequently required inputs/outputs in block form.

The functionality of the new block interface is based on the IM 151-1 BASIC and comprises an interface module and 32 chan-nels in one block.

A total of 80 channels can be connected to SIMATIC ET 200S COMPACT. Therefore 12 modules can be combined as desired – simple input/output modules and integrated technologies.

ET 200S COMPACT

CENELEC II 3 G EEx nA II T4/T5

FM Class I Division 2Groups A, B, C, D, T4/T5Class I Zone 2 IIC, T4/T5

Temperatur 0 °C bis +60 °C



SIMATIC ET 200Mthe multi-channel S7-300 I/O

ET 200M with S7-300 modules

The ET 200M distributed I/O station is a modular DP slave with IP20 degree of protection. Up to 8 multi-channel sig-nal modules (e.g. 32 digital inputs) and function modules as well as communications processors from the S7-300 range can be connected as I/O modules – the interface to the process.

It is not necessary to observe any slot rules. Hot swapping is permissible when using active bus modules.

Connecting to the PROFIBUS is carried out by means of inter-face modules – also using fiber-optic cables as an option.

In addition to screw-type and spring-loaded terminals, con-nection of the signals can be made even simpler and faster us-ing SIMATIC TOP connect. Preassembled front connectors with single conductors or a complete plug-in modular system are available.

The plant availability can be increased when operating the ET 200M with an S7-400H/FH:

■ Switched connection: One ET 200M with two interface modules

■ Redundant connection: Two ET 200M with one interface module each

With connection of the ET 200M to an S7-400, configuration in run (CiR) is possible

This means that

■ complete ET 200M I/O systems can be added,

■ individual modules can be added within a station, and

■ individual digital and analog module parameters can be modified.

Hot swapping of signal modules is possible, thus reducing down times.

Failsafe I/O modules permit integration into safety-relevant systems with SIMATIC Safety Integrated.

CENELEC II 3 G EEx nA II T4/T5

FM Class I Division 2Groups A, B, C, D, T4/T5Class I Zone 2 IIC, T4/T5

Temperatur 0 °C ... +60 °C


Further information 31

Further information

SIMATIC ET 200 for distributed automation solutionsBrochure 6ZB5310-0FM02-0BA.

Distributed applications for hazardous areasCD-ROM, English/German E20001-W70-P240-V1-7400

References

Directive 94/9/EC of the European Parliament and Council of March 23, 1994, on the approximation of the laws of the Member States concerning devices and protective systems for approved use in hazardous areas Official Gazette of the European Council, No. L 100/1

K. Nabert and G. Schön:Safety parameters for combustible gases and vaporsDeutscher Eichverlag, Braunschweig

DIN VDE 0170/0171 Part 1 ff. (EN 50014 ff.)Electrical equipment for hazardous areasDIN VDE 0470 Part 1 (EN 60529) IP degrees of protection; contact, foreign body and water protection for electrical equipmentDIN VDE 0165/02.91Installation of electrical equipment in hazardous areasDIN EN 60079-14 VDE 0165 Part 1:1998-08Electrical equipment for areas with gas explosion hazardElectrical equipment in hazardous areasVDE-Verlag GmbH, Berlin

NFPA 70 - 1996 National Electrical Code, Ausgabe 1996National Fire Protection Association, Quincy, MA, USANFPA 70 - 1999 National Electrical Code, Ausgabe 1999National Fire Protection Association, Quincy, MA, USA1998 Canadian Electrical Code, 18. AusgabeCanadian Standards Association, Etobicoke, ON, Canada1996 National Electrical Code Review and Application GuideKillark Electric Manufacturing Company, St. Louis, MO, USA1998 Canadian Electrical Code Review and Application GuideHubbell Canada Inc. - Killark, Pickering, ON, Canada

PublicationFundamentals of explosion protectionR. STAHL SCHALTGERÄTE GMBH,Waldenburg


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Siemens AG

Automation and DrivesIndustrial Automation SystemsPostfach 48 4890327 NÜRNBERGGERMANY

www.siemens.com/automation

The information provided in this brochure contains descriptions or charac-teristics of performance which in case of actual use do not always apply as described or which may change as a result of further development of the products. An obligation to provide the respective characteristics shall only exist if expressly agreed in the terms of contract. Availability and technical specifications are subject to change without notice.

All product designations may be trademarks or product names of Siemens AG or supplier companies whose use by third parties for their own purpo-ses could violate the rights of the owners.

Further information can be found in the Internet

SIMATIC Guide Manuals:www.siemens.com/simatic-docu

Order or download additional informative material:www.siemens.com/simatic/printmaterial

SIMATIC partners:www.siemens.com/automation/partners

A&D Mall internet ordering system:www.siemens.com/automation/mall

Distributed I/O:www.siemens.com/et200


http://www.siemens.com/simatic-docu

http://www.siemens.com/simatic/printmaterial

http://www.siemens.com/automation/partners

http://www.siemens.com/automation/mall

http://www.siemens.com/et200

http://www.siemens.com/automation

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