SUPPLEMENT FEATURE MACHINE SAFETY
ISO 14119:2013 - the standard for interlocking devices associated with guards
The new standard ‘ISO 14119:2013 Safety of machinery - Interlocking devices associated with guards - Principles for design and selection’ has arrived and will replace EN 1088 within 18 months. David Collier CMSE, business development manager at Pilz UK reports
Left: early compliance with the new ISO 14119 can only be advantageous for machine builders
Types 3 & 4 (non-contact devices, uncoded and coded) did not exist in EN 1088, and examples of their use are given in Annex C and D of ISO 14119. The type of guard locking is expanded
from power to lock or power to release, to include bistable locks where power can be applied to lock and release a solenoid guard switch - it also considers the circumstances under which the use of electromagnetic locks (just the use of electromagnetic force without tongue) is allowed for machine safety (e.g. taking into account the distance to the hazard, the stopping time in the event of power loss, monitoring the holding force, and providing clear indication when forced entry has been attempted).
A
lthough there is an 18 month transition from EN 1088, machine
builders who design safety gate systems will be at an advantage if they aim to comply with the new ISO 14119 immediately. Technologies exist which can overcome challenges, like fault masking, and when deployed can provide added peace of mind as well as compliance with the more exacting requirements of this new standard. In contrast to the previous standard EN
1088, ISO 14119 considers additional technologies such as RFID or electromagnetic guard locking, classifies interlocking switches and regulates more clearly the specifications for installing
S8 APRIL 2014 | MACHINE SAFETY
guards. These regulations are particularly significant with regard to protection against guard manipulation, also known as defeating of guards. ISO 14119 will replace all national standards on this subject and will be valid worldwide. Formally this signifies a huge step forwards - the old standard was purely European, whereas the new standard is published by ISO. The first point is that ISO 14119 now takes into account many technologies now available which weren’t when ISO 1088 was first published. The table above shows an overview of the interlocking types and a helpful cross reference to the examples in the annex of the standard.
Want to learn more? Point your mobile device at the QR code or copy this URL into your browser to access the full article:
http://goo.gl/EW1OCt
DEFEATING OF INTERLOCKING DEVICES Section 7 states that ‘The machine shall be designed in such a way that it minimizes the motivation for defeating the interlocking devices’ and goes on to stipulate ‘The interlocking device shall provide the minimum possible interference with activities during operation and other phases of machine life, in order to reduce any incentive to defeat it’. Various measures are described to realise these requirements (for example preventing access to the interlocking device, preventing the use of substitute actuators through levels of coding and integration of defeat monitoring by cyclic testing). The use of fault exclusions has long been covered in EN 62061 (max SIL 2), TR ISO 23849 (PLd) and now also in EN ISO 13849-2 (Annex D.8 a single mechanical point of failure (the tongue or cam) cannot be fault excluded for PLe). This limitation to PLd for fault exclusions now appears in ISO 14119. In other words to achieve PLe, using at least two devices is mandatory - it is one reason we are seeing more non-contact devices being used for PLe since they have no single mechanical point of failure.
Pilz Automation
www.pilz.com T: 01536 460 766
Enter 235 /AUTOMATION
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56