Explosion-proof emergency stop device

Explosion-proof emergency stop devices are subject to both Directive 2014/34/EU (ATEX 114) and Machine Directive 2006/42/EC.

The emergency stop function must be designed in such a way that the decision to operate the emergency stop devices does not require the person to think about any consequences resulting from it.

The emergency stop devices must be permanently installed, so that it is easy for the operator to press in the event of danger. When pushbuttons are used, it should be possible to actuate them easily with the palm of one’s hand.

The emergency stop function must be available and operational at all times. It must have priority over all other functions and work processes in all types of operations of the machine without adversely affecting other protective functions.

The emergency stop function must be designed in such a way that, once the emergency stop devices has been actuated, any dangerous movements are stopped and the operation of the machine is suitably prevented without causing additional hazards and without any further intervention.

An electrical emergency stop device must apply the compulsory opening principle with a mechanical locking function. Electrical emergency stop devices meet the requirements of EN 60947-5-5.

Colours and texts

The button of the emergency stop device must be RED. If there is a background behind the actuator and inasmuch as it is realizable, this must be YELLOW.

Neither the control device nor the background of the control device is marked with a text or a symbol. If, for the sake of clarity, a symbol is required, the symbol must comply with IEC 60417-5638.

Resetting

If the emergency stop function has been activated:

• it must be maintained until it is reset manually
• a renewed starting of the work processes that were stopped by the initiation of the emergency stop function must not be possible.

The emergency stop function must be reset by a conscious act of one person. An emergency stop function must be reset by unlocking an emergency stop device. The reset must not initiate a restarting of the machine or installation.

The emergency stop function must not adversely affect the effectiveness of other safety functions.

Measures against unintentional activation

The emergency stop device must be designed in such a way that any unintentional activation is avoided. Measures against the unintentional activation of an emergency stop device must not create a risk of hindering the operation or the accessibility of the emergency stop devices. Provided that it is feasible, any unintentional activation must preferably be avoided by the arrangement than by constructional measures.

Certain precautions can be taken to avoid an unintentional activation, for example:

• positioning the emergency stop device far from areas that are expected to be very busy,
• selection of the type of emergency stop device,
• selection of the suitable size and form of the emergency stop device, or
• mounting the emergency stop device in a recessed surface of the surrounding control station.

The use of a protective collar around the emergency stop device to avoid any unintentional operation should be restricted to applications where other measures are not practicable.

A protective collar must not have sharp corners or edges or rough surfaces that could cause injury. Corners and edges must be deburred and the contact areas of surfaces must be smooth.

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