Area Classification

Basic Awareness Training for all Staff

Explosion!

Oxygen Ignition

* Flammable Material

* plus

* Oxygen

* plus

* Source of Ignition

Flammable Material

Properties of Materials

Oxygen Ignition

*Flash Point

* Auto Ignition Temperature

* Flammable Range - % Volume

* Gas / Vapour Density - Air = 1

* Source of Ignition

Flammable Material

ZONE DEFINITIONS* Zone 0

* A Zone in which an explosive atmosphere is continuously present, or present for long periods. (> 1000 hours per year)

* Zone 1

* A Zone in which an explosive atmosphere is likely to occur in normal operation.

(10 to 1000 hours per year)

ZONE DEFINITIONS* Zone 2

* A Zone in which an explosive atmosphere is not likely to occur in normal operation, and if it occurs it will only exist for a short time.

* (1 to 10 hours per year)

* NON-HAZARDOUS AREA

* An area in which an explosive gas/air mixture is not expected to be present in quantities such as to require special precautions for the construction, use and maintenance of electrical equipment.

ZONE LOCATIONS* Zone 0* Inside a solvent tank or solventbased manufacturing vessel

* Zone 1* Solventbased paint production areas, around mixers, filling machines, dispersers, etc.. Up to 1.5 to 2m from the floor (vapours are heavier than air) .

* Zone 2* Drum park, warehouse, upper part of production areas, generally around and beyond zone 1, lab benches and floors to 0.5m high.

ZONE DEFINITIONS* Zone 2

* A Zone in which an explosive atmosphere is not likely to occur in normal operation, and if it occurs it will only exist for a short time.

* (1 to 10 hours per year)

* NON-HAZARDOUS AREA

* An area in which an explosive gas/air mixture is not expected to be present in quantities such as to require special precautions for the construction, use and maintenance of electrical equipment.

Registration.

A Register of all electrical equipment in hazardous areas will be held in the Engineering Department by the Site Responsible Engineer or Responsible Engineer.

Each electrical system shall carry a unique reference number.

Up to date listings are to be maintained.

Any new electrical system must be identified and recorded on theRegister in order to ensure that it is regularly inspected.

Electrical Equipment Register

* Use of electrical items

* Avoidance of static electricity - USE EARTHING LEADS

* Control of visitors / equipment (hot work certificate)

* Maintenance work on electrical items. (hot work certification)

* Modification of electrical items

* Damage to electrical items

* Fastening / enclosure of electrical items

* Vehicles (hot work certificate)

IMPLICATIONS OF AREA CLASSIFICATIONS

Show the location and vertical and horizontal extent of the zone 0, 1 and 2 areas.

Where is your area classification drawing?

Make sure it is up-to-date, and consulted by people issuing permits to work.

Area Classification Drawings

Labelling of Equipment

E = European StandardEx = this equipment has some form of

hazardous area protectionia, ib, d, e, n, etc.. = type of protectionIia, Iib, Iic = gas groupT1, 2, etc = temperature rating Certificate numberCertifying body

Electrical Equipment* Zone 0- Ex ia Exs

* Zone 1- Exa Exib Exp Exe Exs Exd * Zone 2- Ex N Ex o Ex q

EEx i Intrinsic Safety

Non Haz Hazardous

Instrumentation

EEx i Intrinsic Safety

Non Haz Hazardous

Incapable of causingan explosion

Inductance and capacitance are limited

Specific fault conditions

EExd Flameproof Enclosure

L

W

• Gas Inside

• Internal Explosion

• Withstands Pressure

• No flame or heat transmission to outside

• Strength must not be reduced

Eexd Flameproof Enclosure

w

Motors

L

Light Fittings

Pushbuttons

Ammeters

Switchgear

EExd Flameproof Enclosure

w

Bolt sizes and length

Covers

L

Glands

Flange Integrity

Surfaces - Clean-Cooling

EEx e Increased SafetyEnclosure

w

By Design

No excess temperatures

No Arcs or sparks

L

EEx e Increased SafetyEnclosure

w

Terminal and connectionboxes

Outer boxes of devices with other

protection eg. EEx ed Lights

Motors - Germany

L

EEx q Powder Filling Enclosure

Transformers,Capacitors,ElectronicAssemblies, ie.Laboratory Balances

EEx q Powder Filling Enclosure

Potentially sparking equipment under finely granulated material.

No explosion generated even though there may be a spark

EEx p Pressurised Apparatus

Fresh air, inert gas or other suitable gas

Higher pressure than surrounds

Initial purge then maintain the pressure

Eex p Pressurised Apparatus

Switch rooms

Control Panels

Fork Lift TrucksSome individual Instruments

Some Motors

Eex o Oil Immersion Enclosure

Potentially sparking parts immersed in oil

The explosive atmosphere cannot reach the incendive parts

Transformers-rarely used now

Ex m Moulding

Potentially sparking parts are enclosed in Resin

No explosion due to sparking or heating within the resin

Ex m Moulding

Only small capacity switch gear, controlgear, indicating equipment sensors