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Basic information on explosion protection
and the marking of explosion-proof equipment.

BASICS EXPLOSION PROTECTION

What are the Causes for an Explosion

Basically there are three factors that must be encountered when creating a potentially explosive area. Presence of oxygen, an explosive medium and an ignition source. The absence or avoidance of one of the three factors prevents an explosion.
Based on this fact, the three possible strategies to avoid an explosion:

Primary Explosion Protection

Measures which prevent or limit the formation of a potentially explosive atmosphere (avoiding explosive atmospheres).

Secondary Explosion Protection

Measures which prevent the ignition in a dangerous explosive atmosphere (avoiding of ignition sources).

Tertiary Explosion Protection

Measures limiting the effects of an explosion to a safe level (constructional explosion protection).

Thus, the components put on the market by pi are protected to be no sources of ignition and thus are a measure of secondary explosion protection.

Zones – Explanation and Classification

Hazardous areas in which potentially explosive environments can form are classified in zones according to the duration of the potential formation of a dangerous explosive environment

For gases, these are zones 0, 1 and 2. In the case of dusts, a distinction is made between zones 20, 21 and 22.

Classification of Zones for Gases:

Zone 0

A dangerous, explosive atmosphere as a mixture of air, combustible gases, vapors or mists is constantly, for long periods of time or frequently present.

Zone 1

A hazardous, explosive atmosphere as a mixture of air, combustible gases, vapors or mists is occasionally present during normal operation.

Zone 2

A dangerous, explosive atmosphere as a mixture of air, flammable gases, vapors or mists is usually not available or only for a short time.

Classification of Zones for Dusts:

Zone 20

A dangerous, explosive atmosphere in the form of a cloud of combustible dust is constantly, for long periods or frequently present.

Zone 21

A dangerous, explosive atmosphere in the form of a cloud of combustible dust is occasionally present during normal operation.

Zone 22

A dangerous, explosive atmosphere in the form of a cloud of combustible dust is usually not available or only for a short time.

Legal Basis

As a legal basis for the area of explosion protection, the following norms and regulations apply in addition to the usual standards:

ATEX Directive 2014/34/EU

EU Explosion Protection Ordinance ExVo

Ordinance on Industrial Health and Safety

Also, a distinction is made between operator and manufacturer.
Accordingly, the different labeling: