Developement and innovation
Languages: Castellano ES English EN



ATEX

ATEX

The Atex directive was first published in Spain on April 8 of 1996 in the BOE like a royal ordinance 400/ 1996, it dictates the minimum dispositions that should complete devices and systems of protection for use in potentially explosive atmospheres.

A potentially explosive atmosphere is defined like that mixture with the air, in atmospheric conditions of inflammable substances in gases form, fog or powder, in which, after an ignition the combustion spreads to the entirety of the mixture not burned. Any atmosphere that can be converted in explosive due to local circumstances of operation, is what we call a potentially explosive atmosphere.

According to ATEX directive, the zones with presence of explosive atmospheres are divided in two main groups:

I GROUP:
Includes those underground works and their surface facilities where a potential danger because of the presence of methane and/ or combustible powder exists.


GRUPO II:
Places in which there is danger of formation of explosive atmospheres that are not included in I Group.

As a way of protection, it should be understood a series of constructive rules of the materials and electric devices of such form that they could be capable for their employment with security in an explosive atmosphere.

A schematic summary of the characteristics of the several ways of protection complied by national and international regulations is detailed in the following chart:

TYPE OF PROTECTION

Norm

type

Scheme

Protection Mode

CENELEC EN 50019
CEI 79-7
UNE 21819

e

Increased safety:
Refers to an electrical apparatus with a high safety coefficient. Such an apparatus is free from excessively high temperatures and, like under normal service conditions, cannot develop inside and outside electric arcs and sparks.

CENELEC EN 50018
CEI 79-1
UNE 21818

d

Flameproof enclosure:
Refers to an electrical apparatus whose explosive parts are enclosed in an explosion proof casing. This casing will resist the pressure generated by the internal explosion of an explosive mixture and will prevent the explosion from penetrating to the ambient explosive atmosphere.

CENELEC EN 50020
CEI 79-11
UNE 21820

i

Intrinsically safety:
Refers to a circuit in which neither sparks nor temperature can ignite an explosive atmosphere, if generated under the service conditions specified by the standard regulations (normal and faulty operating conditions).

CENELEC EN 50016
CEI 79-2
UNE 21816

p

Pressurization:
Mode of protection based on placing a high pressured protective gas into the capsule to avoid lower pressured explosive atmosphere to get into.

CENELEC EN 50015
CEI 79-5
UNE 21815

o

Immerse in oil:
The electric material or part of it is submerged in oil in such a way that the explosive atmosphere above the level of oil or outside of the cover cannot get inflammable.

CENELEC EN 50017
CEI 79-6
UNE 21817

q

Powder Filling:
In this mode, the cover that contains the electric material is filled with powder so no arches produced inside, or an excessive warm-up on the case wall, can provoke an inflammation on the adjacent atmosphere.

CENELEC EN 50028

m

Encapsulation:
Refers to a special casing in which the parts, of an electrical apparatus which could ignite an explosive atmosphere by either sparking or heating, are encapsulated in a compound in such a way that this explosive atmosphere cannot be ignited.

CENELEC EN 50021
CEI 79-15
UNE 21821

n

Simplified:
Mode of protection that applied to the electric material, impede an ignition of an explosive mixture during the usual functioning. There are 3 categories: Against sparks (nA), Restrain Exhalation (nR) and Simplified for zone 2 (nC).

 

s

Special:
This mode refers to the production procedures no mentioned above, along with the combination of several modes of protection used in a material or electric equipment to obtain a high security coefficient.





BARTZ · Avda. de los Artesanos, 52 · 28760 Tres Cantos (Madrid) · Tel: (+34) 91 803 12 12