Control FunctionsControl ReliabilityEU European UnionFunctional SafetyInternationalISO 13849Standards

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 Nav­ig­a­tionISO 13849 – 1:2006”>Inconsistencies in ISO 13849 – 1:2006

2 thoughts on “31-Dec-2011 – Are YOU ready?

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