RA101 — Introduction to Risk Assessment

Learn Machinery Risk Assessment anytime and anywhere. 

Intro­duc­tion to Risk Assess­ment is our 12-week machin­ery risk assess­ment course, based on ISO 12100:2010 and ISO/TR 14121–2:2012 stan­dards. Deliv­ered online, this course fea­tures wide­ly accept­ed method­ol­o­gy that can be used with­out mod­i­fi­ca­tion in Cana­da, the EU, and the USA. Con­tin­ue read­ingRA101 — Intro­duc­tion to Risk Assess­ment”

Online Training Centre Opens

Online Training Centre Opens

You’ve been chal­lenged to start doing risk assess­ments on your machine designs, but you don’t know where to start. Per­haps you’ve bought a few stan­dards or a book or two, hop­ing to fig­ure it all out, but you nev­er seem to be able to stay focused long enough to get what you need from these mate­ri­als.

You need train­ing. You start the hunt in the Google search box, but find­ing the right kind of train­ing is daunt­ing. How do you know what you need?

Search no longer! Com­pli­ance inSight Con­sult­ing opened it’s online Train­ing Cen­tre this month and is now tak­ing enrol­ments for the char­ter class in Machin­ery Risk Assess­ment!

Risk Assessment 101

Risk Assess­ment 101 is designed for machin­ery design­ers, tech­nol­o­gists and engi­neers who need to get a han­dle on the basics of risk assess­ment. The course includes 12 mod­ules, cov­er­ing

  • the basics of risk
  • haz­ard iden­ti­fi­ca­tion and analy­sis
  • like­li­hood of injury
  • risk con­trol mea­sures
  • risk assess­ment work­flow
  • doc­u­men­ta­tion
  • next steps

The course includes a live class each week, unit quizzes to help learn­ers gauge their under­stand­ing, live office hours with the instruc­tor each week, a Face­book dis­cus­sion group, and much more. Stu­dents suc­cess­ful­ly com­plet­ing the course will receive a Cer­tifi­cate of Achieve­ment.

The Char­ter Class is lim­it­ed to 15 stu­dents and is being offered at a spe­cial intro­duc­to­ry price. If you’re inter­est­ed, don’t waste any time, enroll right away to secure a seat.

Future Courses

Over the next few months, addi­tion­al cours­es will be added to the Train­ing Cen­tre on top­ics like CE Mark­ing, Func­tion­al Safe­ty, Machine Guard­ing, and much more. Some cours­es will be self-direct­ed, while oth­ers will have live class­es as part of the pro­gram.

Our goal at CIC is to pro­vide our cus­tomers with a con­ve­nient, afford­able way to get the train­ing they need when they need it. We hope to see you in class soon!

ISO 13849–1 Analysis — Part 1: Start with Risk Assessment

This entry is part 1 of 9 in the series How to do a 13849–1 analy­sis

I often get ques­tions from clients about how to get start­ed on Func­tion­al Safe­ty using ISO 13849. This arti­cle is the first in a series that will walk you through the basics of using ISO 13849. Keep in mind that you will need to hold a copy of the 3rd edi­tion of ISO 13849–1 [1] and the 2nd edi­tion of ISO 13849–2 [2] to use as you go along. There are oth­er stan­dards which you may also find use­ful, and I have includ­ed them in the Ref­er­ence sec­tion at the end of the arti­cle. Each post has a Ref­er­ence List. I will pub­lish a com­plete ref­er­ence list for the series with the last post.

Where to start?

So you have just learned that you need to do an ISO 13849 func­tion­al safe­ty analy­sis. You have the two parts of the stan­dard, and you have skimmed them, but you are feel­ing a bit over­whelmed and unsure of where to start. By the end of this arti­cle, you should be feel­ing more con­fi­dent about how to get this job done.

Step 1 — Risk Assessment

For the pur­pose of this arti­cle, I am going to assume that you have a risk assess­ment for the machin­ery, and you have a copy for ref­er­ence. If you do not have a risk assess­ment, stop here and get that done. There are sev­er­al good ref­er­ences for that, includ­ing ISO 12100 [3], CSA Z432 [4], and ANSI B11.TR3 [5]. You can also have a look at my series on Risk Assess­ment.

The risk assess­ment should iden­ti­fy which risks require mit­i­ga­tion using the con­trol sys­tem, e.g., use of an inter­locked gate, a light cur­tain, a two-hand con­trol, an enabling device, etc. See the MS101 glos­sary for detailed def­i­n­i­tions. Each of these becomes a safe­ty func­tion. Each safe­ty func­tion requires a safe­ty require­ments spec­i­fi­ca­tion (SRS), which I will describe in more detail a bit lat­er.

Safety Functions

The 3rd edi­tion of ISO 13849 [1] pro­vides two tables that give some exam­ples of safe­ty func­tion char­ac­ter­is­tics [1, Table 8] and para­me­ters [1, Table 9] and also pro­vides ref­er­ences to cor­re­spond­ing stan­dards that will help you to define the nec­es­sary para­me­ters. These tables should not be con­sid­ered to be exhaus­tive — there is no way to list every pos­si­ble safe­ty func­tion in a table like this. The tables will give you some good ideas about what you are look­ing for in machine con­trol func­tions that will make them safe­ty func­tions.

While you are iden­ti­fy­ing risk reduc­tion mea­sures that will use the con­trol sys­tem for mit­i­ga­tion, don’t for­get that com­ple­men­tary pro­tec­tive mea­sures like emer­gency stop, enabling devices, etc. all need to be includ­ed. Some of these func­tions may have min­i­mum require­ments set by Type B2 stan­dards, like ISO 13850 [6] for emer­gency stop which sets the min­i­mum per­for­mance lev­el for this func­tion at PLc.

Selecting the Required Performance Level

ISO 13849–1:2015 pro­vides a graph­i­cal means for select­ing the min­i­mum Per­for­mance Lev­el (PL) required for the safe­ty func­tion based on the risk assess­ment. A word of cau­tion here: you may feel like you are re-assess­ing the risk using this tool because it does use risk para­me­ters (sever­i­ty, frequency/duration of expo­sure and pos­si­bil­i­ty to avoid/limit harm) to deter­mine the PL. Risk assess­ment This tool is not a risk assess­ment tool, and using it that way is a fun­da­men­tal mis­take. Its out­put is in terms of per­for­mance lev­el, which is fail­ure rate per hour of oper­a­tion. For exam­ple, it is entire­ly incor­rect to say, “This machine has a risk lev­el of PLc” since we define PLs in terms of prob­a­ble fail­ure rate per hour.

ISO 13849-1 graphical selection tool for determining PLr requirement for a safety function
Graph­i­cal Per­for­mance Lev­el Selec­tion Tool [1]
Once you have assigned a required Per­for­mance Lev­el (PLr) to each safe­ty func­tion, you can move on to the next step: Devel­op­ing the Safe­ty Require­ments Spec­i­fi­ca­tion.

Book List

Here are some books that I think you may find help­ful on this jour­ney:

[0]     B. Main, Risk Assess­ment: Basics and Bench­marks, 1st ed. Ann Arbor, MI USA: DSE, 2004.

[0.1]  D. Smith and K. Simp­son, Safe­ty crit­i­cal sys­tems hand­book. Ams­ter­dam: Else­vier/But­ter­worth-Heine­mann, 2011.

[0.2]  Elec­tro­mag­net­ic Com­pat­i­bil­i­ty for Func­tion­al Safe­ty, 1st ed. Steve­nage, UK: The Insti­tu­tion of Engi­neer­ing and Tech­nol­o­gy, 2008.

[0.3]  Overview of tech­niques and mea­sures relat­ed to EMC for Func­tion­al Safe­ty, 1st ed. Steve­nage, UK: Overview of tech­niques and mea­sures relat­ed to EMC for Func­tion­al Safe­ty, 2013.

References


[1]     Safe­ty of machin­ery — Safe­ty-relat­ed parts of con­trol sys­tems — Part 1: Gen­er­al prin­ci­ples for design. 3rd Edi­tion. ISO Stan­dard 13849–1. 2015.

[2]     Safe­ty of machin­ery — Safe­ty-relat­ed parts of con­trol sys­tems — Part 2: Val­i­da­tion. 2nd Edi­tion. ISO Stan­dard 13849–2. 2012.

[3]      Safe­ty of machin­ery — Gen­er­al prin­ci­ples for design — Risk assess­ment and risk reduc­tion. ISO Stan­dard 12100. 2010.

[4]     Safe­guard­ing of Machin­ery. CSA Stan­dard Z432. 2004.

[5]     Risk Assess­ment and Risk Reduc­tion- A Guide­line to Esti­mate, Eval­u­ate and Reduce Risks Asso­ci­at­ed with Machine Tools. ANSI Tech­ni­cal Report B11.TR3. 2000.

[6]    Safe­ty of machin­ery — Emer­gency stop func­tion — Prin­ci­ples for design. ISO Stan­dard 13850. 2015.