Hierarchy of Controls

Forces, people and injuries — How hard is too hard?

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ISO/TS 15066 body model
This entry is part 5 of 5 in the series Hier­archy of Con­trols

For any­one involved in risk assess­ment and con­trol, there are always ques­tions regard­ing the amount of force it takes to injure a per­son. As soon as we decided that hurt­ing people when they were work­ing or using our products was not OK, clev­er people wanted to know what the lim­its were on forces applied to people. […]

Canada

Instructions for Use – the New ISO 20607

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Instruc­tions are one of the basic items that users expect to get when they pur­chase a product, and yet these import­ant doc­u­ments are often poorly writ­ten, badly trans­lated, and incom­plete. Key product fea­tures are badly described, and inform­a­tion on fea­tures, set­tings and haz­ards may be absent. All of this des­pite the fact that the min­im­um require­ments […]

Canada

ISO 13849 – 1 Analysis — Part 8: Fault Exclusion

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

Fault Con­sid­er­a­tion & Fault Exclu­sion ISO 13849 – 1, Chapter 7 [1, 7] dis­cusses the need for fault con­sid­er­a­tion and fault exclu­sion. Fault con­sid­er­a­tion is the pro­cess of examin­ing the com­pon­ents and sub-sys­tems used in the safety-related part of the con­trol sys­tem (SRP/CS) and mak­ing a list of all the faults that could occur in each one. This a def­in­itely non-trivi­al […]

Canada

ISO 13849 – 1 Analysis — Part 5: Diagnostic Coverage (DC)

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A graph showing the theoretical "bathtub curve" for product failure rate over the lifetime of the product.
This entry is part 5 of 9 in the series How to do a 13849 – 1 ana­lys­is

What is Dia­gnost­ic Cov­er­age? Under­stand­ing Dia­gnost­ic Cov­er­age (DC) as it is used in ISO 13849 – 1 [1] is crit­ic­al to ana­lys­ing the design of any safety func­tion assessed using this stand­ard. In case you missed a pre­vi­ous part of the series, you can read it here. In the last instal­ment of this series dis­cuss­ing MTTFD, I brought up the […]

Canada

ISO 13849 – 1 Analysis — Part 4: MTTFD – Mean Time to Dangerous Failure

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This entry is part 4 of 9 in the series How to do a 13849 – 1 ana­lys­is

Func­tion­al safety is all about the like­li­hood of a safety sys­tem fail­ing to oper­ate when you need it. Under­stand­ing Mean Time to Dan­ger­ous Fail­ure, or MTTFD, is crit­ic­al. If you have been read­ing about this top­ic at all, you may notice that I am abbre­vi­at­ing Mean Time to Dan­ger­ous Fail­ure with all cap­it­al let­ters. Using MTTFD is […]

Canada

ISO 13849 – 1 Analysis — Part 3: Architectural Category Selection

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This entry is part 3 of 9 in the series How to do a 13849 – 1 ana­lys­is

At this point, you have com­pleted the risk assess­ment, assigned required Per­form­ance Levels to each safety func­tion, and developed the Safety Require­ment Spe­cific­a­tion for each safety func­tion. Next, you need to con­sider three aspects of the sys­tem design: Archi­tec­tur­al Cat­egory, Chan­nel Mean Time to Dan­ger­ous Fail­ure (MTTFD), and Dia­gnost­ic Cov­er­age (DCavg). In this part of the […]

Canada

ISO 13849 – 1 Analysis — Part 2: Safety Requirement Specification

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This entry is part 2 of 9 in the series How to do a 13849 – 1 ana­lys­is

Devel­op­ing the Safety Require­ment Spe­cific­a­tion The Safety Require­ment Spe­cific­a­tion sounds pretty heavy, but actu­ally, it is just a big name for a way to organ­ise the inform­a­tion you need to have to ana­lyse and design the safety sys­tems for your machinery. Note that I am assum­ing that you are doing this in the “right” order, mean­ing that you […]

Canada

Presence Sensing Devices – Reaching over sensing fields

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This entry is part 2 of 7 in the series Guards and Guard­ing

I recently heard about an applic­a­tion ques­tion related to a light cur­tain where a small gap exis­ted at the top of the sens­ing field, between the last beam in the field and the sur­round­ing struc­ture of the machine. There was some con­cern raised about the gap, and wheth­er or not addi­tion­al guard­ing might be needed to close the gap. […]

Canada

Get the Basics Right!

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For more than 15 years I’ve been teach­ing people about risk assess­ment, machinery safety and CE Mark­ing of machinery in private, onsite classes and through present­a­tions at safety con­fer­ences. Things are about to change! This fall, Com­pli­ance InSight Con­sult­ing will begin offer­ing open-enrol­­ment work­shops in CE Mark­ing, Risk Assess­ment Func­tion­al Safety, and Machinery Safety, all with a focus […]