ATEX Information

An explosive atmosphere is a mixture of dangerous substances with air, under atmospheric conditions, in the form of gases, vapours, mist or dust in which, after ignition has occurred, combustion spreads to the entire unburned mixture

There are many substances that can form an explosive atmosphere; for example, gases (natural gas, butane, propane, acetylene, etc.), liquids (propellants, solvents, oils, paints, etc.) and solids (wood, coal, cereal grains, metal powder) and therefore many installations and activities that must be evaluated according to regulations.

Directive 99/92/CE provides that the employer must take the appropriate measures to prevent the formation of explosive atmospheres or, where the nature of the activity does not allow that, to prevent the ignition of explosive atmospheres, and mitigate the adverse effects of an explosion so as to ensure the health and safety of workers.

To classify the areas, you must follow and take into account the international standards (UNE/IEC 60079-10) and the physical and chemical parameters of the substances liable to cause explosive atmospheres. It is therefore possible to identify the site based on the characteristics of the substances in the facility.

Classification of site areas

TYPE OF AREA	AREA FOR GASES, VAPOURS AND MIST	AREA FOR COMBUSTIBLE SOLID DUST
Work area in which an explosive atmosphere is always or frequently present, or for a prolonged period of time.	0	20
Work area in which the occasional formation of an explosive atmosphere is likely under normal operating conditions.	1	21
Work area in which the formation of an explosive atmosphere is unlikely under normal operating conditions. If an explosive atmosphere forms, it only remains for a short period of time.	2	22

To classify the areas, you must follow and take into account the international standards and the parameters of the substances liable to cause them. It is therefore possible to identify the location based on the characteristics of the substances in the facility.

In addition to identifying hazardous areas, companies with ATEX areas must protect electrical and non-electrical equipment intended for use in potentially explosive atmospheres. Similarly, they must guarantee a certain level of safety depending on the area of the facility and therefore must have undergone specific tests and certification tests carried out by recognised organisations.

How do you know which ATEX marking an ATEX luminaire should have?

GROUPS

GROUP	DETAIL
I	FIREDAMP Mining equipment
II	Equipment for surface installations

AREA	EQUIPMENT TYPE
0/20	1
1/21	2
2/22	3

ENVIRONMENT

SIGN	MEANING	AREAS
G	GAS	0,1,2
D	DUST	20,21,22
GD	GAS AND DUST	0/21-1/21-2/22

PROTECTION MODES FOR ELECTRICAL DEVICES

MODE	SYMBOL	STANDARD
Flameproof	d	UNE-EN 60079-1
Increased safety	e	UNE-EN 60079-7
Restricted breathing	n	UNE-EN 60079-15
Surround	t	EN 60079-31

GAS SUBGROUP

SUBDIVISION	DESCRIPTION	COMPATIBILITY
IIA	Butane, hexane, methane, acetone, fuel-oil…	IIA, IIB, IIC
IIB	Ethylene, cyclopropane, dioxane…	IIB, IIC
IIB + H2	Any of the above + Hydrogen	IIB+H2, IIC
IIC	Hydrogen, acetylene, carbon disulfide	IIC

Subgroup IIC covers IIB+H2, HB and IIA

DUST SUBGROUP

SUBDIVISION	DESCRIPTION	MATERIALS PERMITTED GROUP
IIA	Inflammable particles	IIA, IIB, IIC
IIB	Non-conductive dust	IIB, IIC
IIC	Conductive dust	IIC

Subgroup IIIC covers IIIB and IIIA

GAS TEMPERATURE CLASS

Temperature class	Maximum surface temperature of the equipment
T1	450°C
T2	300°C
T3	200°C
T4	135°C
T5	100°C
T6	85°C

The self-ignition temperature T6 covers T1 to T6

DUST TEMPERATURE CLASS

Temperature class	Maximum surface temp. of electrical equipment
T85°C	Máx 85°C
T100°C	Máx 100°C
T135°C	Máx 135°C
T200°C	Máx 200°C
T300°C	Máx 300°C
T450°C	Máx 450°C

The self-ignition temperature T85 covers T85 to T450

LEVEL OF PROTECTION

MODE	EPL GAS	EPL DUST	MEANING	AREA
d	Gb	Db	Very high protection	1/21
e	Gb	Db	High protection	1/21
nR	Gc	Dc	Medium protection	2/22

DEGREE OF PROTECTION IP

	DUST PENETRATION		WATER PENETRATION
0	No protection	0	No protection
1	Protection from objects larger than 50 mm	1	Protection from vertical dripping
2	Protection from objects larger than 12.5 mm	2	Protection from dripping at an angle 15º
3	Protection from objects larger than 2.5 mm	3	Protection from spraying
4	Protection from objects larger than 1 mm	4	Protection from splashes
5	Protection from dust	5	Protection from water jets
6	Totally dust-proof	6	Protection from constant water jets
	The IP69K rating is the highest level of protection available and is compatible with high-pressure cleaning and steam cleaning equipment.	7	Protection from temporary immersion
		8	Protection from permanent immersion