270 likes | 294 Views
Area Classification. Basic Awareness Training for all Staff. Explosion!. * Flammable Material * plus * Oxygen * plus * Source of Ignition. Oxygen. Ignition. Flammable Material. Properties of Materials. *Flash Point * Auto Ignition Temperature * Flammable Range - % Volume
E N D
Area Classification Basic Awareness Training for all Staff
Explosion! * Flammable Material * plus * Oxygen * plus * Source of Ignition Oxygen Ignition Flammable Material
Properties of Materials *Flash Point * Auto Ignition Temperature * Flammable Range - % Volume * Gas / Vapour Density - Air = 1 * Source of Ignition Oxygen 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.
Electrical Equipment Register 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 the Register in order to ensure that it is regularly inspected.
IMPLICATIONS OF AREA CLASSIFICATIONS * 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)
Area Classification Drawings • 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.
Labelling of Equipment • E = European Standard • Ex = this equipment has some form of hazardous area protection • ia, ib, d, e, n, etc.. = type of protection • Iia, Iib, Iic = gas group • T1, 2, etc = temperature rating • Certificate number • Certifying 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 Instrumentation Non Haz Hazardous
EEx i Intrinsic Safety Incapable of causing an explosion Inductance and capacitance are limited Specific fault conditions Non Haz Hazardous
EExd Flameproof Enclosure • Gas Inside • Internal Explosion • Withstands Pressure • No flame or heat transmission • to outside • Strength must not be reduced L W
Eexd Flameproof Enclosure L Switchgear Motors Light Fittings Pushbuttons Ammeters w
EExd Flameproof Enclosure L Bolt sizes and length Covers Glands Flange Integrity Surfaces - Clean- Cooling w
EEx e Increased SafetyEnclosure L By Design No excess temperatures No Arcs or sparks w
EEx e Increased SafetyEnclosure L Terminal and connection boxes Outer boxes of devices with other protection eg. EEx ed Lights Motors - Germany w
EEx q Powder Filling Enclosure Transformers, Capacitors, Electronic Assemblies, 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 Trucks Some 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, control gear, indicating equipment sensors