Machinery Safety 101

How to migrate from EN 954 – 1 to EN ISO 13849 – 1 or EN 62061

Edit­or­’s note – When I read this art­icle on the machinebuilding.net blog, I thought that it was import­ant enough that we should reprint it here. The text includes links to the machinebuilding.net web site. These resources can def­in­itely help you in apply­ing this inform­a­tion. If you have ques­tions that you would like to dis­cuss, please con­tact me and I would be happy to assist you!

This art­icle ori­gin­ally appeared on machinebuilding.net, and is reprin­ted with per­mis­sion.

by Jon Severn

EN 954 – 1 ceased to be cur­rent at the end of 2011, so com­pan­ies still using this machinery safety stand­ard need to migrate to either EN ISO 13849 – 1 or EN 62061. This art­icle provides a roadmap to aid the trans­ition.

Rock­well Auto­ma­tion repor­ted at a Machinery Safety event in 2011 that many com­pan­ies sup­ply­ing machines to the European mar­ket are still work­ing to EN 954 – 1 (Safety of Machinery – Design of safety related con­trol sys­tems), even though this stand­ard would be with­drawn at the end of that year (see EN 954 – 1 exten­sion con­firmed as two years). Moreover, there are sound reas­ons for using the new­er func­tion­al safety stand­ards instead (see this art­icle EN 954 – 1 and ten reas­ons NOT to use it).

If you are a machine build­er work­ing to EN 954 – 1 you should, ideally, migrate to one of these two func­tion­al machinery safety stand­ards as soon as pos­sible:

  • EN ISO 13849 – 1Safety of machinery, Safety-related parts of con­trol sys­tems, Part 1: Gen­er­al prin­ciples for design
  • EN 62061 (IEC 62061), Safety of machinery, Func­tion­al safety of safety-related elec­tric­al, elec­tron­ic and pro­gram­mable elec­tron­ic con­trol sys­tems

This art­icle provides a roadmap to assist machine build­ers in mak­ing the trans­ition.

EN 954 – 1 and CE marking

New machines need to be CE marked if they are to be placed on the mar­ket in the European Eco­nom­ic Area (EEA), Switzer­land or Tur­key. The same is true wheth­er the machine is sold to anoth­er com­pany or built for use in-house. In addi­tion, an exist­ing machine may be classed as ‘new’ (and there­fore need CE mark­ing) if it is sig­ni­fic­antly mod­i­fied or upgraded (eg by ret­ro­fit­ting a manu­al machine tool for CNC oper­a­tion).

Until the end of 2011 EN 954 – 1 provided a ‘pre­sump­tion of con­form­ity’ to the new Machinery Dir­ect­ive, so com­ply­ing with this stand­ard was suf­fi­cient to meet cer­tain of the Essen­tial Health and Safety Require­ments (EHSRs) of the Dir­ect­ive. Of course, there will almost cer­tainly be oth­er Har­mon­ised stand­ards with which the machine should com­ply to provide a pre­sump­tion of con­form­ity with oth­er EHSRs.

If the machine build­er was con­struct­ing a one-off machine to be placed on the mar­ket before the end of 2011, then there could be an argu­ment for work­ing to EN 954 – 1 (but see EN 954 – 1 and ten reas­ons NOT to use it). How­ever, if there was a chance that the machine would not be delivered by the 31 Decem­ber dead­line, or if series pro­duc­tion meant that future deliv­er­ies were anti­cip­ated, then EN 954 – 1 should prefer­ably have been dropped in favour of one of the func­tion­al safety stand­ards.

To decide which of the func­tion­al safety stand­ards to use, see the IEC/TR 62061 – 1 guide to applic­a­tion of ISO 13849 – 1 and IEC 62061. In most cases the safety-related con­trol sys­tem will be designed to EN ISO 13849 – 1, as this caters for non-elec­tric­al as well as elec­tric­al haz­ards (EN 62061 relates only to elec­tric­al, elec­tron­ic and pro­gram­mable elec­tron­ic con­trol sys­tems). Much has been writ­ten about the pro­cesses involved in determ­in­ing the EN ISO 13849 – 1 Per­form­ance Level (PL) required and achieved, but bear in mind that there is also a Sim­pli­fied pro­ced­ure for assess­ing PL to EN ISO 13849 – 1.

Which Directive?

While the main focus of this art­icle is to provide a roadmap for the trans­ition from EN 954 – 1 to EN ISO 13849 – 1 or EN 62061, this has to be con­sidered in the con­text of CE mark­ing. If the machine is being CE marked, is it being CE marked to the old or new Machinery Dir­ect­ive? Or is com­pli­ance with the new Dir­ect­ive being claimed, even though no thor­ough assess­ment has been car­ried out since the machine was CE marked to the old Dir­ect­ive? To help machine build­ers check their level of com­pli­ance with the ‘new’ Machinery Dir­ect­ive 2006/42/EC (which has been cur­rent since 29 Decem­ber 2009), MachineBuilding.net has pub­lished a free Guide to the New Machinery Dir­ect­ive that high­lights the dif­fer­ences between the old and new Dir­ect­ives and dis­cusses the implic­a­tions of the changes.

Hav­ing decided on the best func­tion­al safety stand­ard to use for the machine in ques­tion, it will be neces­sary to update the design doc­u­ment­a­tion and Declar­a­tion of Con­form­ity accord­ingly. In some cases minor changes to the design of the safety-related con­trol sys­tem may also be neces­sary.

Design­ers should also check that the cor­rect pro­ced­ures are being fol­lowed, and that the doc­u­ment­a­tion is in order as required by the new Machinery Dir­ect­ive (for example, EC Type Exam­in­a­tion Cer­ti­fic­ates issued under the old Dir­ect­ive need to be updated before con­form­ity with 2006/42/EC can be claimed). And, depend­ing on the type of machine, design­ers should assess wheth­er any oth­er Dir­ect­ives are applic­able.

A note about standards

In order to claim com­pli­ance with a stand­ard, it is really neces­sary to own a copy. Unless the machine build­er already owns up-to-date cop­ies of the rel­ev­ant stand­ards, buy­ing them can be expens­ive. If buy­ing from BSI, sav­ings can be made by becom­ing a Mem­ber, as the 50 per cent dis­count off the cost of stand­ards might more than pay for the mem­ber­ship fee, depend­ing on the num­ber of stand­ards pur­chased and the fee, which, in turn, depends on the type of organ­isa­tion and its turnover.

Resources and support

While the fore­go­ing provides some assist­ance for migrat­ing from EN 954 – 1 to EN ISO 13849 – 1 or EN 62061, tak­ing any neces­sary action may require the use of vari­ous resources, many of which are avail­able free of charge. MachineBuilding.net has iden­ti­fied the fol­low­ing, but please email the edit­or (editor@machinebuilding.net) if you are aware of any oth­ers.

  • IEC/TR 62061 – 1 ed1.0 Guid­ance on the applic­a­tion of ISO 13849 – 1 and IEC 62061 in the design of safety-related con­trol sys­tems for machinery. This doc­u­ment describes which stand­ards can and can­not be used in dif­fer­ent scen­ari­os, and dis­cusses the ways in which one stand­ard may be pre­ferred over anoth­er.
  • Free books have been pub­lished by Rock­well Auto­ma­tion (Safe­book 4 and EN ISO 13849 – 1), Pilz, TUV SUD Product Ser­vice (ex-Laidler Asso­ci­ates) and Sick.
  • Ded­ic­ated machinery safety web­sites have been cre­ated by Rock­well Auto­ma­tion and Wie­land Elec­tric.
  • Free and paid-for train­ing courses and sem­inars are avail­able from many pro­viders includ­in­gRock­well Auto­ma­tion, Pilz, TUV SUD Product Ser­vice (ex-Laidler Asso­ci­ates), Sick, Wie­land Electric,Leuze elec­tron­ic, Health & Safety Com­pli­ance Engin­eer­ing, PPMA (Pro­cessing & Pack­aging Machinery Asso­ci­ation), Health and Safety Labor­at­ory (HSL), Festo, ISS Safety, Oxeta, Safe­Mech and theM­a­chinery Safety Alli­ance.
  • Procter Machine Guard­ing offers a num­ber of Free down­loads includ­ing a Design­er­’s Guide to Machinery Guard­ing Stand­ards, a Risk Assess­ment Cal­cu­lat­or, a Safety Dis­tance Cal­cu­lat­or, and two White Papers, one on the sub­ject of Machinery Dir­ect­ive and Fix­ings for Fixed Guards and the oth­er onCE Mark­ing of Guards.
  • Pilz offers its PAS­cal Safety Cal­cu­lat­or for cal­cu­lat­ing the PL (Per­form­ance Level) and SIL (Safety Integ­rity Level) when work­ing to EN ISO 13849 – 1 and EN/IEC 62061, respect­ively.
  • SISTEMA, which is main­tained by Ger­many’s IFA, is a free soft­ware util­ity for apply­ing EN ISO 13849 – 1; most of the lead­ing man­u­fac­tur­ers of safety products sup­ply free com­pon­ent lib­rar­ies con­tain­ing the neces­sary data for use with­in SISTEMA.
  • A free EN ISO 13849 – 1 Per­form­ance Level Cal­cu­lat­or is also avail­able from the IFA; this simple tool con­sists of two discs and, by rotat­ing the bot­tom disc, val­ues for Per­form­ance Levels can be found for dif­fer­ent mean times to dan­ger­ous fail­ure, cat­egor­ies and dia­gnost­ic cov­er­age.
  • Docufy is a risk assess­ment tool that links to Sis­tema to aid CE mark­ing. As well as the full ver­sion, there are free tri­al and free­ware ver­sions avail­able
  • Tech­nic­al sup­port is offered by many of the machinery safety com­pon­ent sup­pli­ers; some­times this comes free of charge, while at oth­er times you will have to pay for the con­sultancy or engin­eer­ing ser­vices – ask around, as the value of the free ser­vices can be sub­stan­tial.
  • Machinery Safety Alli­ance has been formed by Festo, Fort­ress Inter­locks, Pilz Auto­ma­tion Tech­no­logy, Troax, UK Engin­eer­ing and Werma; the aim is to help machine build­ers com­ply with safety stand­ards and legis­la­tion while, at the same time, safe­guard­ing pro­ductiv­ity. As well as hav­ing a web­site with a use­ful set of inform­at­ive art­icles, the Machinery Safety Alli­ance is organ­ising a series of machinery safety sem­inars
  • It is import­ant that safety-related con­trol sys­tem designs are val­id­ated (see this art­icle from TUV SUD Product Ser­vice (ex-Laidler Asso­ci­ates): The need for val­id­a­tion of safety-related con­trol sys­tem designs); Pilz also offers a safety val­id­a­tion ser­vice for machine build­ers, val­id­a­tion is included with­in Rock­well Auto­ma­tion’s port­fo­lio of Machine Safety Ser­vices, and sev­er­al of the oth­er com­pan­ies men­tioned above can also val­id­ate machine build­ers’ designs.

Giv­en the wealth of resources avail­able, most machine build­ers should find it rel­at­ively straight­for­ward to migrate from EN 954 – 1 to EN ISO 13849 – 1 or EN 62061, though the applic­a­tion of the lat­ter can be more dif­fi­cult. But the import­ant point to note is that after the end of 2011 EN 954 – 1 ceased to be cur­rent and no longer provides a pre­sump­tion of con­form­ity to the Machinery Dir­ect­ive. Although it will, strictly speak­ing, remain leg­al to place machinery on the mar­ket that has been designed in accord­ance with EN 954 – 1 rather than one of the new­er func­tion­al safety stand­ards for machinery, machine build­ers are advised to make the trans­ition. The soon­er this is done, the bet­ter, as no doubt there will be high demand for the tech­nic­al sup­port from com­pon­ent sup­pli­ers now the dead­line has passed.

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