Selection of explosionprotection measures fordust extracting system

Is the dustexplosive?

Separation of metal dust?

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YES

NOExamples: mineral dust, ceramic dust, normally stainless steel, welding fume

No additional measures necessary

Examples: organic dust,light metal dust, steel dust

Can an explosive environment be avoided?

Evaluation criteria(Responsibility with operator)

Operator’s safety data sheet required

Evaluation by means of GESTIS dust-ex data base

Dust examination by KL/testing institute

Dosing unit with weight monitoring

Detection of mixing ratio

Wet separation (only with exhaust air operation)

Solid inertisation (small amount of dust)

YESNo additional measures necessary

TO SOME EXTENT

(Dry separator)

NOAvoidance of ignition sources within the extraction system

MIE > 10 mJ (normal ignition energy) – and can the collection of effective ignition sources be excluded?

YES No additional measures necessary

Potential equalization ductwork

Potential equalization filter system

ATEX componentsPackage "Ignition source avoidance"

Outdoor installation

Installation at an outside wall

NO

NO

Horizontal pressure relief by burst panels

Safety zone approx. 10 - 20 m

Reduced safety zone (approx. 2.5 - 3.5 m)Vertical pressure relief (deflection by burst panels)

YES

Horizontal pressure relief by burst panels + safe keeping

Angular pressure relief by burst panels + Targo-Vent + safe-keeping

Safety zone approx. 10 - 20 m

Reduced safety zone (approx. 7 - 14 m)YES

NO

For processes with a small amount of dust and rare ignition sources

Cleaning during downtimeProSens protection concept

Monitoring for access by ignition sources

ProVentPlus (with TR-1)

ProPipe

ProPipePlus

ProSens (see above)Pressure shock resistance normally 10 bar

Safety zoneFlameless pressure relief for aluminum dust at KST = 300

No safety zone

Flameless pressure relief for aluminum dust at KST = 180

No safety zone

Flameless pressure relief for aluminum dust at KST = 180

Design on Pmax

YES

Explosion suppression

Flameless pressure relief ProVent

No safety zonePressure shock resistance normally 0.4 barWith toxic dusts, gases/hybrid mixtures

Pressure shock resistance normally 0.4 bar

Safety zoneNO

Selection of fire protection measures with air pollution control systems

Internal ignition sources within system

External ignition sources

Examples:- Hot surfaces- Static electricity

Can be eliminated with protective measures

Ignition sources in the event of a fault

Protection version A no ignition sources under normal operating conditions

No mechanical fire-prevention measures

Examples:- Mechanically created sparks e. g. grinding processes- Flames and hot gases e. g. thermal spraying, welding- Hot particles e. g. glowing sparks from machine tool

Protection version BMeasures to prevent fires

Protection version CMeasures for damage control

Ignition sources under normal operating conditions

Spark pre-separatoin

Spark detection and extinguishing

Solid matter inertization

Cyclone separator Separation of ignition sources and particles

Separation of coarse particles

Energy extraction through contact with baffle plates, not suitable for larger volumes of dust

Impact separator

Cascade separatorNon-cumbustible dust(BZ = 1)

Combustible dust(BZ > 1) Fire detection

Manual fire fightingSimple extinghuisher opening Extinguishing by third parties

Semi-stationary extinguishing system - not all components built in- effective only after applying extinguishing agent

Stationary extinguishing system- all components built in- detection, signaling, extinguishing fires in the earliest stages

ABC powder extinguishing

Fire department

Manual extinguishing agents:- Argon- D-Powder- ABC-Powder

Automatic extinguishing - Extinguishing system

water extinguishing

Fire hazard due to:- Filter elements- Secondary material, e. g. oil-bearing air- Dust

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Protection version BMeasures see mentioned above

Examples:- Mechanically created sparks e. g. malfunction in machine tools- Exothermal reactions, including spontaneous combustion of dusts e. g. accumulation of dust in Big-Bag