Types of Explosion Protection

Protection principles are defined to prevent equipment and components becoming ignition sources.

The protection principles can be applied to;

• electrical
• non-electrical equipment
• gases
• dusts

In industrial settings, in hazardous areas like those found in oil & gas, chemical, or pharmaceutical industries, equipment is classified as either electrical or non-electrical based on whether it uses electricity to function.

Electrical equipment refers to devices that operate using electrical power. These components can generate sparks or heat, which is why they must be specially designed for use in explosive atmospheres.

Examples of electrical equipment are:

• Control panels
• Lighting fixtures
• Power distribution boxes
• Human Machine Interfaces (HMI)

Explore BARTEC electrical equipment below.

The principles allow for a design in various safety categories in accordance with the ATEX Directive 2014/34/EU (ATEX Blue Guide) or the Equipment Protection Level (EPL) according to EN / IEC 60079 series:

Ignition sources which are caused by sparks from friction or impact or from electro-static charging have to be prevented in explosion protected equipment by selecting appropriate materials and by constructive measures, and this must be verified and confirmed by appropriate tests.

There are different protection principles which can prevent equipment from becoming an ignition source.

An important precondition for all the protection principles is that parts which are in unhindered contact with the explosive atmosphere must not be able to reach non-permitted temperatures with respect to the ignition temperature of substances present in the site of installation. This means that the ignition temperature is relevant for all protection principles.

1. Explosive mixtures can enter the equipment in which an ignition source may be located and be ignited. The transmission of internal ignition to the surrounding atmosphere shall be excluded.

Examples of types of protection:

• Flameproof enclosures (Ex d)
• Powder (quartz) filling (Ex q)

2. The operating equipment has an enclosure which prevents the penetration of the explosive mixture and/or contact with the internal function-related potential sources of ignition.

Examples of types of protection:

• Pressurized enclosures (Ex p)
• Protection by enclosures (Ex t)
• Liquid immersion (Ex o)
• Encapsulation (Ex m)

3. Explosive mixtures can penetrate the enclosure of the operating equipment but is not allowed to be ignited. Any spark is prohibited and temperatures capable of causing ignitions shall be prevented.

Examples of types of protection:

• Increased Safety equipment (Ex e)

4. Explosive mixtures can penetrate the enclosure of the operating equipment but can’t be ignited. The occurrence of spark energy and increased temperatures shall be limited.

Examples of types of protection:

• Intrinsically safe (Ex i)

5. Optical radiation is used but it is prevented to cause an ignition.

There are three different types:

• Ex op is: Inherently safe optical radiation
• Ex op pr: Protected optical radiation
• Ex op sh: Optical system with interlock

It applies to all types of protection where parts that are in unhindered contact with the explosive atmosphere are not permitted to reach unacceptably high temperatures.

Taking into account both the environmental temperature and the heating effect, the temperature may attain maximum values which corresponds to the temperature class or the permissible temperature specified for flammable dusts in accordance with which the explosive atmosphere has been classified.

Marking examples in accordance with ATEX directive 2014/34/EU according to EN 60079 series and IECEx System according to IEC 60079 series.

Information specific to explosion protection (marking)

A:  The name or the registered trademark of the manufacturer

B:  The manufacturer’s type identification

C:  Rated Voltage

1. Conformity mark (CE)
2. Identification number of the Notified Body which - where required - certified the QA system or examined the products (Category 1 and 2)
3. Ex mark (community Epsilon x logo) Equipment group II - other areas (non-mining)
4. Equipment category 2 either - gases/vapours G, suitable for Zones 1 and 2 or - dusts D, suitable for Zones 21 and 22
5. EU-Type Examination Certificate Notified Body name or symbol, year and Notified Body’s certificate registration number
6. IECEx Certificate of Conformity (CoC) Certification Body’s symbol, year and Certification Body’s certificate registration number
7. Explosion protection in compliance with EN 60079 series, Type of protection: flameproof enclosure and increased safety (gas) - marked Ex d and Ex e, protection by enclosure (dust) - marked Ex t all types of protection having high level of protection b-
8. Group IIC (most easy ignitable gases), Group IIIC (conductive dusts)
9. Temperature class T6 (gas), max. surface temperature T80°C in absolute value (dust)
10. Equipment protection level Gb (high protection level) (gas), equipment protection level Db (high protection level) (dust)
11. 1. "X" observe Specific conditions of use: e. g. “the light module must be installed in a way that ensures its mechanical protection from impact energy in accordance with EN IEC 60079-0”
    2. “U” Ex Component which is not intended to be used alone. Conformity is certified when installed into a complete operating equipment. Components don’t have any temperature class
12. Ambient temperature range Marking in accordance with INMETRO (Example)

ATEX Blue Guide

ATEX Directive 2014/34/EU

EN/ IEC 60079-0