bira-wat symposium 20060316 final

8/3/2019 BIRA-WAT Symposium 20060316 Final

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How to Run General Purpose Analyzersin Potentially Explosive Atmospheres(Considerations are Limited to EEx II G)

Norbert ZeugBARTEC BENKE GmbHD-21465 Reinbek

BIRA WAT SymposiumMortsel, March 16th, 2006


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Legal Regulations

ATEXHarmonised General Conditions in Europe

Explosion Protection

Directive 94/9/EC

(for Manufacturers)

Conformity AssessmentPotential ignition source

(electrical and non electrical) duringnormal operation, expected or rare

unit malfunction:

Unit Groups, -categories

Directive 1999/92/EC

(for Operators)

Assessment of Explosion Risktemporal behaviour of flammable

components (Gas and Dust)

classification of hazardous areas

Zones


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Basic Questions

Area ClassificationZone 1explosive atmosphere is likely to occur in normal operation occasionally

Zone 2explosive atmosphere is not likely to occur in normal operation but, if it does

occur, will persist for a short period onlyTemperature Class

T1 450CT2 300C

T3 200CT4 135CT5 100CT6 85C

Explosion Sub GroupsA (examples: methane, ethane, ammonia, gasoline,)B (B+H2) (examples: ethylene, ethylene oxide, hydrogen sulphide,..)C hydrogen, acetylene, carbon disulphide


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Planning Analyser Systems

What can we do, if general purpose analysersshould/must be used?

Two possible approaches

Approach 1

following Directive 94/9/ECApproach 2following Directive 1999/92/EC


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In both approaches we need to consider theCause of Risk

External Sourcedangerous amount of an explosive atmosphere inthe environment of the analyser system

Internal Sourcedangerous amount of an explosive atmosphere viathe introduction of the sample stream itself(flammable product to be measured)

Planning Analyser Systems


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Approach 1: Directive 94/9/EC

Approved Types of Protections:

European/International Norm Description

EN 60079-0 / IEC 60079-0 general requirements

EN 60079-1 / IEC 60079-1 flameproof enclosure d

EN 60079-2 / IEC 60079-2 pressurized enclosure pEN 60079-5 / IEC 60079-5 powder filling q

EN 60079-6 / IEC 60079-6 oil immersion o

EN 60079-7 / IEC 60079-7 increased safety e

EN 60079-11 / IEC 60079-11 intrinsic safety i

EN 60079-15 / IEC 60079-15 type of protection n (category 3G)

EN 60079-18 / IEC 60079-18 encapsulation m


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Pressurized Enclosure p

EN 60079-2 valid since June 2004EN 50016transition period till June 1st, 2007

For current projects both norms can beused


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EEx p Control Systems for Zone 1

Purge phaseClosed enclosure is purged with purge gasAutomatic dilution of potentially presentexplosive gas mixtures to a safe level

Operation phaseCreation and monitoring of an internaloverpressurePreventing the intrusion of an explosive

atmosphere from outside (permanent purge orcompensation for leakage losses)Switch on of all general purpose devices

MalfunctionOverpressure drops below 0.5 mbarAll general purpose devices are shut downautomatically


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Simplified Procedure for Zone 2

Purge phase not strictly requiredIt is required to ensure, that no explosiveatmosphere is present when the system isenergised

manual purge usage of gas sensors etc.

Operation phase

Identical to Zone 1Malfunction

No automatic shut down necessary

Alarming is sufficient


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Analysers EEx p Packaged

Non flammable Samples:including gas mixtures which are below LEL at any time

Most simple case

Analyser can be treated like any other electricalequipment

Purge gas: air

Overpressure sustained via leakage compensationInstallation in Zone 1:

EEx p control system with automatic purge phase andshut down in case of pressure loss

Installation in Zone 2:according to simplified procedure


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Introduction of Flammable Samples:

Examination of the Containment System

This means:Checking the internal sample path for potential leakagesChecking for ICAs (Ignition-Capable Apparatus)

Flame arresters for sample gas inlet and outletif a potential ignition source is in the gas path

Two cases to be considered

a) no leakage possiblefail-safe containment

b) quantifiable amount of leakagecontainment with limited leakage


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Introduction of Flammable Samples:

Decision Matrix (only EN 60079-2)

measuringcell

electronics

power anddata cables

hazardous area

sample lines

(restricted flow)

physical state

of sample

normal

operationmalfunction case

gas or liquid no no A

gas or liquid no yes B

gas yes yes C

liquid yes yes

Limited Leakage

STOP


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Introduction of Flammable Samples:Case A fail-safe containment

Valid for gases and liquidsPurge gas: air sufficient

No permanent purge requiredpurge gas loss compensation sufficient

Installation in Zone 1EEx p control system with automatic purge phaseand shut down in case of pressure loss

Installation in Zone 2according to simplified procedure

measuringcell

electronics


for instanceweldedconnections

hazardous area

sample lines

(restricted flow)


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Introduction of Flammable Samples:Case A fail-safe containment

Overpressure of purged cabinet > sample pressure

Only valid for gases

Purge gas: air sufficient

Purge gas loss compensationInstallation in Zone 1automatic EEx p control system

precautions that overpressure of containment is50 Pa above sample pressure at any time


measuringcell

electronics


simple screwfittings,O-rings, etc.

hazardous area

sample lines

(restricted flow)

A l EE P k d


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hazardous area

electronics

measuringcell

Introduction of Flammable Samples:Case B containment with limited leakageonly during failure situation

Method 1Dilution via permanent air purge

Valid for gases

ICAs outside dilution zoneInstallation in Zone 1automatic EEx p control systemprecautions that purge gas dilutes leaking gas to

< 25% LELInstallation in Zone 2according to simplified proceduresame precautions as Zone 1

sample lines

(restricted flow)

A l EE P k d


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hazardous area

electronics

measuringcell

Introduction of Flammable Samples:Case B containment with limited leakage

only during failure situation

Method 2Inert gas purge (N2, CO2, Ar) with loss compensation

Gases and liquidsOxygen content < 2%

UEL < 80%

Installation in Zone 1automatic EEx p control system


sample lines

(restricted flow)

A l EE P k d


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hazardous area

electronics

measuringcell

Introduction of Flammable Samples:Case B containment with limited leakageonly during failure situation

Method 3Dilution via permanent inert gas purge (N2, CO2, Ar)

Liquids and gases containing oxygen > 2%or gases with UEL > 80%

Method not suitable for liquids with UEL > 80%Installation in Zone 1automatic EEx p control systemprecautions that purge gas dilutes possible oxygen

content to < 2%Installation in Zone 2according to simplified proceduresame precautions as Zone 1

sample lines

(restricted flow)

A l EE P k d


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Introduction of Flammable Samples:Case C containment with limited leakage

normal operation and failure situation

Dilution via permanent air purge

Only valid for gases

Installation in Zone 1

EEx p control system with automatic purge phaseprecautions that purge gas dilutes leaking gas to< 25% LEL

Installation in Zone 2

according to simplified proceduresame precautions as Zone 1



hazardous area

electronics

measuringcell

sample lines

(restricted flow)

Required Hardware


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Required Hardware

ATEX certified EEx p Control Unit

for instance control units from BARTEC

Cabinet which fulfils the requirements of

EN 60079-02EN / IEC 60079-0

IP code according to IEC 60529

APEX for Zone 1

SILAS for Zone 2

How to Comply with the Regulation


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Zone 2 applicationEEx p packaging is done by a supplier manufacturer declaration plus manual

EEx p packaging is done by plant operator itself written risk assessment description of concept attachments to the explosion protection document manual

Zone 1 applicationOne-off approval for specific usedone by an authorised person (e.g. TV in Germany)

EEx p packaging is done by a supplier who owns aATEX certificate for EEx p systems (BARTEC BENKE)

Please consider national and regional

regulations too!

Analyser Communication


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Analyser Communication

Via serial interfacePC must be located ingeneral purpose area orexplosion proofed itselfConnection switched off in caseof purge loss

Built-in Touch Panel PC

Example


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Example

fail-safe containment solution

EC-type examination certificateUniversal Cabinet (TV 04ATEX2403)

Ex protection type: II 2G EEx p II T4

Done by BARTEC BENKE

Process Mass Spectrometer for flammable Gases

Example


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Example

Separation of electric parts from wet partsvia optical fibresBased on Bruker Matrix FT-NIR spectrometerEC-type examination certificateUniversal Cabinet (TV 04ATEX2403)Ex protection type: II 2G EEx p II T4

Done by BARTEC BENKE

Process FT-NIR Spectrometer for liquid Samples

Some Additional Considerations


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Some Additional Considerations

General purpose analyzers are not designed forharsh environment

Temperature fluctuation can cause severe

problems measurement accuracyEx climatisation could be necessary

Solution:

BARTEC BENKEsCompact Air Conditioning UnitATEX certified for Zone 1TV 97 ATEX 1224 X



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Analyser System is not treated as an apparatusbut as an installation (plant component)Applying the EN 61285 (IEC 1285) normProcess Control

Safety of Analyser Houses



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Consideration of internal and external sources

Generation of overpressure (25 50Pa) viaintake of fresh air from general purpose area

(on suction intake from Zone 2 air-intake duct must bemonitored with an LEL-sensor

Limitation of amount of flammable media fed into the shelter50% LEL must not exceeded in case of failure

(please consult national and regional regulations too)Bypasses / fast loops must be installed outside the shelter

It is recommended to install sampling systems outside too

At least 5-fold air change per hourCalculation must consider amount of flammable media(rule of thumb: LEL 0.8% v/v)



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Actions in case of pressure drop inside the shelterpower off of all general purpose equipmentshut off flammable media feed lines outside shelteralarming required

Monitoring of leakagesStrategically located LEL-sensorsConsideration of gas / vapour densities

Flammable liquid mediafloor with sink and drain at the deepest pointliquids with flash point above 55C need not to beconsidered as long as no hot surfaces are present

Entrance from Zone 0 or 1 via sluiceMeasures must be taken for protection againstsubstances harmful to health(not covered in this lecture)




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1 Ex-Air Conditioning Unit 4 Bottle Cabinet2 Bypass/Fast Loop 5 Analyser

3 Sampling System 6 Flash Light, Horn

Sluice

AR SSR

ZONE 1

General PurposeArea

1

4

3

5

6


ZONE 2

GENERAL PURPOSE AREA

2

Assembly Example for Shelters in Zone 1

LEL-SensorAR = Analyser Room

SSR= Sampling SystemRoom



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Sluice

AR SSR

ZONE 1

General PurposeArea

1

4

3

5

6


ZONE 2


2






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AR

SSR

ZONE 2

General PurposeArea

1 2

4

3

5

6

Sa ety o a yse ouses








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AR

SSR

ZONE 2

General PurposeArea

1 2

4

3

5

6

y y








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p y g

written risk assessment

description of concept

list of flash points of all flammable liquids

list of explosion proofed equipment and itscompliance with zone plan

attachments to the explosion protection

document


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?Thank you for your attention

bira-wat symposium 20060316 final

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