§50 指令2014/34/EUの意味における爆発の可能性のある雰囲気

Directive 2014/34/EU is a directive following the "New Approach" and the New Legislative Framework and therefore is intended to enable the free movement of goods within the EU. This is achieved by harmonisation of legal safety requirements, following a risk-related approach. Its objective is also to eliminate or at least minimise the risks resulting from the use of certain products in or in relation to a potentially explosive atmosphere. The manufacturer has to make assumptions about the intended use of his product including the contact with potentially explosive atmospheres.

An explosive atmosphere for the purposes of Directive 2014/34/EU is defined as a mixture i) of flammable substances in the form of gases, vapours, mists or dusts; ii) with air; iii) under atmospheric conditions; iv) in which, after ignition, the combustion spreads to the entire unburned mixture (It has to be noted that sometimes (mainly with dusts) not always the whole quantity of the combustible material is consumed by the combustion).

An atmosphere which could become explosive due to local and/or operational conditions, is called a potentially explosive atmosphere. It is only this kind of potentially explosive atmosphere which products falling under the ATEX Directive 2014/34/EU are designed for.

It is important to note that products are not covered by Directive 2014/34/EU where they are intended for use in or in relation to mixtures which might potentially be explosive, but one or more of the defining elements i) to iv) above are not present. For example:

A product within a potentially explosive mixture without the presence of air is not in the scope of the Directive. Special processes of this type require equipment that has been specially designed for the risks, as equipment intended for use in potentially explosive atmospheres may pose an ignition hazard for mixtures under non-atmospheric conditions.

Conveying equipment where some parts but not all are under atmospheric pressure with internal pressures different from atmospheric pressure can fall under the scope of Directive 2014/34/EU. When performing a risk assessment it will become evident that although parts of the described equipment are outside the scope of Directive 2014/34/EU during normal operation (pressure oscillates between too low and too high values in relation to "atmospheric conditions") some parts or spaces still are under the scope and that the whole equipment during start-up and shut-down is under the scope, at least.

So, both the following examples fall under the scope of Directive 2014/34/EU:

a) A vapour recovery pump for petrol stations is connected at its inlet and outlet to a potentially explosive atmosphere in the sense of Directive 2014/34/EU.

b) A vacuum pump sucking from a vacuum container and conveying the mixture into a pressure vessel or pressure line is in scope of Directive 2014/34/EU just during starting and shutting down phases. In this case the inner parts of the pump are connected to a potentially explosive atmosphere in the sense of Directive 2014/34/EU.

Note: The manufacturer may wish to sell this equipment for use under atmospheric conditions of the inlet and outlet side additionally, and then case a) applies. In any case, the complete working cycle needs to be considered, including start-up and shut-down, which may cause an atmospheric pressure to exist. If the equipment is not intended for atmospheric use, the Directive does not apply. Risk assessment must be carried out according to Directive 1999/92/EC.

As long as the user is not able to ensure the absence of a potentially explosive atmosphere, start-up and shut-down are relevant to determine the application of the Directive.