ISO publishes ISO 14119:2013 for guard interlocks

This new standard replaces ISO 14119:1998, which has been technically revised. It also incorporates Amendment ISO 14119:1998/Amd 1:2007. The main changes from before are:

• an improved structure as a result of the differentiation and definition of four types of interlocking devices,
• a description of their technology and their typical characteristics in annexes,
• "defeat in a reasonably foreseeable manner" is now defined and considered,
• the measures required to minimise defeat possibilities, and
• the consideration of new technologies and the addition of informative Annexes G, H and I.

The informative Annexes A to F describe the technology and the typical characteristics of the defined four types of interlocking devices. However, the standard points out that other solutions may be adopted, provided they comply with the principles of ISO 14119. The informative Annexes G to I give information on particular aspects such as interlocking devices used within safety functions, and risk assessment considering the motivation to defeat and static action forces.

Technical Report ISO/TR 24119 is under preparation and will give information on the masking of faults when interlocking devices are connected in series.

Within the scope of ISO 14119, there are two important notes:

• ISO 14119 does not necessarily provide all the specific requirements for trapped key systems.
• ISO 14119 provides measures to minimise defeat of interlocking devices in a reasonably foreseeable manner.

Definition of interlocking device

ISO 14119 defines an interlocking device as: mechanical, electrical or other type of device, the purpose of which is to prevent the operation of hazardous machine functions under specified conditions (generally as long as a guard is not closed).

In addition, ISO 14119 contains a useful diagram to illustrate the definition and help explain what is meant by interlocking device: essentially the interlocking device comprises an actuator and position switch; the position switch, in turn, comprises an actuating system and an output switch.

Follow the link to read an article about ISO 14119:2013, the new standard for guard interlocking devices, and how it differs from EN 1088, the Euronorm machinery safety standard that it replaces in Europe.