31-​Dec-​2011 – Are YOU ready?

This entry is part 8 of 8 in the series Circuit Architectures Explored

31-​December-​2011 marks a key mile­stone for machine build­ers mar­ket­ing their products in the European Union, the EEA and many of the Candidate States. Functional Safety takes a pos­it­ive step for­ward with the man­dat­ory applic­a­tion of EN ISO 13849 – 1 and -2. As of 1-​January-​2012, the safety-​related parts of the con­trol sys­tems on all machinery bear­ing a CE Mark will be required to meet these stand­ards.

This change star­ted six years ago, when these stand­ards were first har­mon­ized under the Machinery Directive. The EC Machinery Committee gave machine build­ers an addi­tion­al three years to make the trans­ition to these stand­ards, after much oppos­i­tion to the ori­gin­al man­dat­ory imple­ment­a­tion date of 31-​Dec-​08 was announced.

If you aren’t aware of these stand­ards, or if you aren’t famil­i­ar with the concept of func­tion­al safety, you need to get up to speed, and fast.

Under EN 954 – 1:1995 and the 1st Edition of ISO 13849 – 1, pub­lished in 1999, a design­er needed to select a design Category or archi­tec­ture, that would provide the degree of fault tol­er­ance and reli­ab­il­ity needed based on the out­come of the risk assess­ment for the machinery. The Categories, B, 1 – 4, remain unchanged in the 2nd Edition. I’ve talked about the Categories in detail in oth­er posts, so I won’t spend any time on them here.

The 2nd Edition brings Mean Time to Failure into the pic­ture, along with Diagnostic Coverage and Common Cause Failures. These new con­cepts require design­ers to use more ana­lyt­ic­al tech­niques in devel­op­ing their designs, and also require addi­tion­al doc­u­ment­a­tion (as usu­al!).

One of the main fail­ings with EN 954 – 1 was Validation. This top­ic was sup­posed to have been covered by EN 954 – 2, but this stand­ard was nev­er pub­lished. This has led machine build­ers to make design decisions without keep­ing the neces­sary design doc­u­ment­a­tion trail, and fur­ther­more, to skip the Validation step entirely in many cases.

The miss­ing Validation stand­ard was finally pub­lished in 2003 as ISO 13849 – 2:2003, and sub­sequently adop­ted and har­mon­ized in 2009 as EN ISO 13849 – 2:2003. While no man­dat­ory imple­ment­a­tion date for this stand­ard is giv­en in the cur­rent list of stand­ards har­mon­ized under 2006/​42/​EC-​Machinery, use of Part 1 of the stand­ard man­dates use of Part 2, so this stand­ard is effect­ively man­dat­ory at the same time.

Part 2 brings a num­ber of key annexes that are neces­sary for the imple­ment­a­tion of Part 1, and also out­lines the com­plete doc­u­ment­a­tion trail needed for val­id­a­tion, and coin­cid­ent­ally, audit. Notified bpdies will be look­ing for this inform­a­tion when eval­u­at­ing the con­tent of Technical Files used in CE Marking.

From a North American per­spect­ive, these two stand­ards gain access through ANSI’s adop­tion of ISO 10218 for Industrial Robots. Part 1 of this stand­ard, cov­er­ing the robot itself, was adop­ted last year. Part 2 of the stand­ard will be adop­ted in 2012, and RIA R15.06 will be with­drawn. At the same time, CSA will be adopt­ing the ISO stand­ards and with­draw­ing CSA Z434.

These changes will finally bring North America, the International Community and the EU onto the same foot­ing when it comes to Functional Safety in indus­tri­al machinery applic­a­tions. The days of “SIMPLE, SINGLE CHANNEL, SINGLE CHANNEL-​MONITORED and CONTROL RELIABLE” are numbered.

Are you ready?

Compliance InSight Consulting will be offer­ing a series of train­ing events in 2012 on this top­ic. For more inform­a­tion, con­tact Doug Nix.

Series NavigationInconsistencies in ISO 13849 – 1:2006

Author: Doug Nix

+DougNix is Managing Director and Principal Consultant at Compliance InSight Consulting, Inc. (http://www.complianceinsight.ca) in Kitchener, Ontario, and is Lead Author and Managing Editor of the Machinery Safety 101 blog.

Doug's work includes teaching machinery risk assessment techniques privately and through Conestoga College Institute of Technology and Advanced Learning in Kitchener, Ontario, as well as providing technical services and training programs to clients related to risk assessment, industrial machinery safety, safety-related control system integration and reliability, laser safety and regulatory conformity.

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