User`s manual

EXPLOSION-PROOF EXECUTION EQUIPMENT FOR HAZARDOUS AREAS

Hazardous areas are locations where, under given conditions, potentially explosive atmospheres may develop.

An explosive atmosphere cons

ists of air mixed with: combustible gas, vapor or dust. In an explosive atmosphere, a rapidly

spreading combustion (explosion) may take place following its ignition at atmospheric pressure caused by a triggering source

such as a hot surface, a spark, eithe

r of an electric or mechanic nature, the presence of a flame or an exothermic reaction. In order

for an explosion to take place it is therefore necessary that air, or other gaseous mixture containing oxygen, inflammable ma

terial

and a triggering source should all be present at the same time.

The first big difference between components operating in hazardous atmospheres is determined by the environment in which

they operate. Electrical appliances are divided into two groups.

Group I: electrical appliances for use in mines with firedamp gas

Group II: electrical appliances for use in other explosive atmospheres

Italkrane is mainly involved with Group II appliances. The dissertation hereunder refers to this Group.

Under the 1999/92/EC directive, regarding Group II, the user is required to classify hazardous areas, subdividing them into

zones on the basis of the frequency and duration of the presence of explosive atmosphere. That same European Directive

divides appliances into three categories with different levels of protection and connects them with the areas of use so as to

guarantee the same level of safety in all zones.

In proportion to the kind of substances present in classified areas, areas are dived in zone 1, 2, 3 and zone 20, 21, 22.

When the risk is due to the presence of flammable gases, vapors or mists, the classification made based on EN60079-10

regulation, originates three possible zones which are defined as follows:

• Zone 0 = areas where an explosive atmosphere is permanently, or for long periods, present

• Zone 1 = areas where the formation of explosive atmospheres is probable, or possible, under normal conditions

• Zone 2 = areas where explosive atmosphere is not usually present and, when it is present, it is so for short periods.

When hazard is due

to the presence of combustible dust, the classification gives rise to three danger zones named Zone

20, 21 and 22 where the level of risk is defined as above.

Directive 96/9/EC (ATEX) divides appliances into three categories with different levels of pro

tection depending on the zone of

installation in order to guarantee always the same level of protection.

COMBUSTIBLE

SUBSTANCES

GAS AND VAPORS DUST

ZONES 0 1 2 20 21 22

APPLIANCE