The explosion endangered Area

In the European Union, explosion protection is an important part of the health and safety regulations. It is laid down by the commission and has the same guide line in all countries.

In the year 2003 the guideline 94/9/EG known as ATEX 100a come into force and controls the placement of equipment, components and protection systems for special applications as e.g. flammable gases, vapours and dusts into the market.

Due to the new law the difference between requirements of the condition and requirements for the operation must be made very clear.

While the requirements of the conditions should ensure the freedom of the European domestic market, which is controlled by the guide line 94/9/EG, the requirements for the operation (guide line ATEX 118a) are controlled by the national rules and regulations (EtexV (new) and Vbf (new)).

Look attachment "explosion protection directive ATEX 100a and ATEX 118a" by Mr. Helmut Krämer PTB/Braunschweig.

Requirements of the condition

For the description of the different requirements the guide line ATEX 100a diversifies the equipment in different groups. Group I regulates the application of underground exploration, as Group II regulates none exploration areas. To classify the different application of the equipment, it is necessary to diversify the Groups once more.

Therefore Group I separates between Category M1 (Equipment, which are operating in explosion endangered atmosphere) and Category M2 (Equipment which turn off before reaching the first explosion limit).

The equipment which relates to Group II is separated between Category 1,2and 3. While Category 1 describes equipment which is used in potential explosive atmosphere which is existing permanent, on long term or frequent, Category 2 is related to potential explosive atmosphere from time to time. In Category 3 equipment is mentioned which is used in potential explosive atmosphere which happens only on short time respective seldom.

The criteria's for the different areas in which the equipments used are in accordance to the definition of zones of the explosion endangered areas after the rules and regulations of ATEX 118a or DIN EN 1127-1.

Accordingly Category 1 is related for the use in Zone 0 or 20, Category 2 for the use in Zone 1 or 21 and Category 3 for the use in Zone 2 or 22.

The conformity of the guide line of the equipment has to be notified from the supplier/producer in close corporation with the mentioned notified bodies.

Requirements for the operation

Each explosion hazardous area has to be proven and classified by a certified auditor/notified body under the rules and regulations of ATEX 118a. The work of the authorized expert applies to BLMSchG § 29a clause 1, Elektro-Berg VO and the fire protection.

An identification of technical explosion figures for flammable goods should be made independently

The prepared safety analysis includes vulnerability- and risk analysis as well as the fire protection for technical construction.

In so called open areas (e.g. working areas for personal staff) action has to be taken for the prevention of risk of predictable troubles and the state of the operation has to be defined.

As a special example is here to be mentioned the soil condition which has to be demonstrated a special quality in normal operation conditions depending on the classification of the operation.

After DIN EN 61340-4-1 the definition of the earth resistance for the prevention of electrostatic discharge plants, equipment or human applies.

At any time no impact should affect the soil condition in normal operation conditions or suspend it.

The operator has the responsibility for the maintenance and functional capability which defines the internal work flow. Even little contamination could isolate the resistance of the soil. This interruption of the contact is the most reason for failures in normal operation conditions.

The floor suppliers are mentioning explicit in their maintenance instruction to keep the floor clean and to exclude themselves of any kind of liability (e.g. "....the clean floor is only allowed to be entered by clean shoes....").

It is strongly recommended after a careful risk analysis to proceed with a constant cleaning procedure to ensure the security standard.