3.1 Guarding with optoelectronic protective devices

IEC TS 62046 Safety of machinery – Application of protective equipment to detect the presence of persons contains basic information for selecting, applying, connecting and putting electro-sensitive protective equipment and safety mats into operation. It addresses the authors of machine-specific C-standards, designers, test centers and anyone that is involved with the professional installation of such protective devices.

The following information refers to the recommendations of IEC TS 62046 as the international state of technology. In principle to be observed with priority: the operating instructions of the protective devices, regional regulations or machine-specific standards

European C-standards, for example:

EN 692 Machine tools – Mechanical presses – Safety

EN 693 Machine tools – Hydraulic presses – Safety

And in the USA for example:

OSHA 1910.217 Mechanical Power Presses

ANSI B11.1 Mechanical Power Presses – Safety Requirements for Construction, Care, Use

ANSI B11.2 Mechanical Power Presses – Safety Requirements for Construction, Care, Use

ANSI B11.19 Performed Criteria for the Design, Construction, Care and Operation of Safeguarding when referenced by other B11 Machine Tool Safety Standards

Selecting and applying optoelectronic protective devices

In the following it is assumed that a risk assessment, e.g. in accordance with EN ISO 12100-1, has been performed and an optoelectronic protective device has been selected as a measure for minimizing risk.

General safety notes:

• Optoelectronic protective devices do not protect against injuries caused by projected (thrown out) objects or emissions from the machine.
  
  
• The machine must allow the dangerous movement to be stopped at any point of the workflow cycle.
  
  
• Optoelectronic protective devices must be mounted in such a way that reaching into/access to the point of operation is only possible through the protective field. Reaching over, under or stepping behind must be prevented by additional protective devices (e.g. guards).
  
  
• With point of operation guarding (finger and hand protection) and danger zone guarding, people may not enter or be present in the danger zone undetected. Additional protective devices may need to be provided, e.g. stepping behind protection with a host/guest light curtain, for example.
  
  
• The safety distance from the protective device to the point of operation must be big enough that the dangerous movement will have stopped before a part of the person’s body can reach the point of operation (see step 4, calculating safety distance).
  
  
• Reflective surfaces near optoelectronic protective devices can cause objects not to be detected because of the protective device’s beams being reflected. An appropriate minimum distance according to the operating instructions must be observed to prevent this.