ATEX and IECEx Hazardous Area Guidelines

Flashcards covering ATEX and IECEx definitions, explosion conditions, equipment protection levels, modes of protection, and inspection standards.

Atmosphère explosive

A mixture with air, under atmospheric conditions, of flammable substances in the form of gas, vapor, mist, or dust in which, after ignition, combustion spreads to the entire unburnt mixture.

Energie minimale d'inflammation

The minimum amount of energy supplied locally in the form of a flame, spark, impact, or friction to cause the ignition of an explosive atmosphere.

Point d'éclair

The lowest temperature at which a flammable liquid produces sufficient vapor at its surface to ignite when exposed to an ignition source.

Température d'auto-inflammation

The minimum temperature at which an explosive atmosphere ignites spontaneously without an external ignition source.

L.I.E. (Limite Inférieure d'Explosivité)

The minimum concentration of a flammable product in the air above which the gas, dust, or vapor mixture can ignite.

L.S.E. (Limite Supérieure d'Explosivité)

The maximum concentration of a flammable product in the air below which the gas, dust, or vapor mixture can ignite.

DRCPE

Document Relatif à la Protection Contre les Explosions; a document prepared and maintained by the head of an establishment that classifies explosion risk areas.

ATEX Category 1

Equipment designed for a very high level of protection, intended for areas where an explosive atmosphere is present constantly, for long periods, or frequently.

ATEX Category 2

Equipment designed for a high level of protection, intended for areas where an explosive atmosphere is likely to occur.

ATEX Category 3

Equipment designed for a normal level of protection, intended for areas where an explosive atmosphere has a low probability of occurring and persists for only a short period.

Mode of Protection 'e'

Increased safety mode governed by EN 60079-7, where internal components do not produce arcs, sparks, or dangerous temperatures in normal use, requiring IP 54 sealing and impact resistance of $7\,\text{Nm}$.

Mode of Protection 'd'

Flameproof enclosure mode governed by EN 60079-1, featuring a robust enclosure that contains an internal explosion and flameproof joints that prevent flame propagation outside.

Mode of Protection 'ia'

Intrinsic safety mode governed by EN 60079-11, where energy input is limited by a Zener barrier or galvanic isolator to prevent arcs or sparks, suitable for Zone 0.

Mode of Protection 'ta' / 'tb' / 'tc'

Dust-tight enclosure mode governed by EN 60079-31, protecting components against dust ingress using a sealed enclosure.

Mode of Protection 'n'

Non-sparking protection mode governed by EN 60079-15, intended solely for Zone 2 where explosion risk is low.

Mode of Protection 'q'

Powder filling mode governed by EN 60079-5, where components capable of producing arcs or sparks are submerged in an inert powder filling material.

Mode of Protection 'ma'

Encapsulation mode governed by EN 60079-18, where spark-producing components are embedded in an insulating resin material.

Mode of Protection 'pa'

Internal overpressure mode governed by EN 60079-11, maintaining positive internal pressure to prevent surrounding explosive atmospheres from entering.

Temperature Classes T1 to T6

Classification based on maximum surface temperature: T1 ($450\,^\circ\text{C}$), T2 ($300\,^\circ\text{C}$), T3 ($200\,^\circ\text{C}$), T4 ($135\,^\circ\text{C}$), T5 ($100\,^\circ\text{C}$), and T6 ($85\,^\circ\text{C}$).

Directive 2014/34/UE

The EU ATEX directive applicable since April 20, 2016, replacing Directive 94/9/CE to regulate equipment for explosive atmospheres.

Suffix 'X'

Notation at the end of an ATEX certificate reference indicating that the product is subject to special conditions for safe use.

Suffix 'U'

Notation at the end of an ATEX certificate reference indicating an Ex component that cannot be used as a standalone product.

EN 60079-17 Inspection Degrees

Standard establishing three degrees of inspection for electrical installations in hazardous areas: Visual (V), Close (P), and Detailed (D).

Ex d Barrier Cable Gland Rule

Mandated use of compound barrier cable glands on Ex d flameproof enclosures when the internal volume exceeds $2\,\text{dm}^3$.