Machinery Safety 101

Five reasons you should attend our Free Safety Talks

Reason #1 – Free Safety Talks

You can’t argue with Free Stuff! Last week we partnered with Schmersal Canada and Franklin Empire to put on three days of Free Safety Talks. We had full houses in all three locations, Windsor, London and Cambridge, with nearly 60 people participating.

We had two great presenters who helped people understand Pre-Start Health and Safety Reviews (PSRs) [1], CSA Z432-2016 [2], Interlocking Devices [3] and Fault Masking [4].

Mr Vashi at Franklin Empire Cambridge
Mr Vashi at Franklin Empire Cambridge

Franklin Empire provided us with some great facilities and breakfast to keep our minds working. Thanks, Franklin Empire and Ben Reid who organized all of the registrations!

Mr Nix discussing injury rates in machine modes of operation
Mr Nix discussing injury rates in machine modes of operation

Reason #2 – Understanding Interlocking Devices

A portrait of Mr Kartik Vashi
Mr Kartik Vashi, CFSE

Mr Kartik Vashi, CFSE, discussed the ISO Interlocking Device standard, ISO 14119. This standard provides readers with guidance in the selection and application of interlocking devices, including the four types of interlocking devices and the various coding options for each type. Did you know that ISO 14119 is also directly referenced in CSA Z432-16 [2]? That means this standard is applicable to machinery built and used in Canada as of 2016. If you don’t know what I’m talking about, you can contact Mr Vashi to get more information.

ISO 14119 Fig 2 showing some aspects of different types of interlocking devices.
ISO 14119 Fig 2 showing some aspects of different types of interlocking devices [3]

Reason #3 – Understanding Fault Masking

Mr Vashi also talked about fault masking, an important and often misunderstood situation that can occur when interlocking devices or other electromechanical devices, like emergency stop buttons, are daisy-chained into a single safety relay or safety input on a safety PLC. Mr Vashi drew from ISO/TR 24119 to help explain this phenomenon. If you don’t understand the impact that daisy-chaining interlocking devices can have on the reliability of your interlocking systems, Mr Vashi can help you get a handle on this topic.

A part of ISO 24119 Fig 2 showing one method of daisy-chaining interlocking devices.
A part of ISO 24119 Fig 2 showing one common method of daisy-chaining interlocking devices [4]

Reason # 4 – Pre-Start Health and Safety Reviews

Portrait of Doug Nix, C.E.T.
Mr Doug Nix, C.E.T.

Mr Nix opened his presentation with a discussion of some commonly asked questions about Pre-Start Health and Safety Reviews (PSRs). There are many ways that people become confused about the WHY, WHAT, WHEN, WHERE, WHO and HOW of PSRs, and Mr Nix covered them all. This unique-to-Ontario process requires an employer to have machines, equipment, racking and processes reviewed by a Professional Engineer or another Qualified Person when certain circumstances exist (see O. Reg. 851, Section 7 Table). If you are confused by the PSR requirements, contact Mr Nix for help with your questions.

Reason #5 – Understanding the changes to CSA Z432

CSA Z432 [2] was updated in 2016 with many changes. This much-needed update came after 12 years experience with the 2004 edition and many changes in machinery safety technology. Mr Nix briefly explored the many changes that were brought to Canadian machine builders in the new edition, including the many new references to ISO and IEC standards. These new references will help European machine builders get their products accepted in Canadian markets. Both Mr Vashi and Mr Nix sit on the CSA Technical Committee responsible for CSA Z432.

Reason #6 – Hot Questions

We like to over-deliver, so here’s the bonus reason!

We had some great questions posed by our attendees, two of which we are answering in video posts this week. If you have ever considered using a programmable safety system for lockout, our first video explains why this is not yet a possibility. Mr Nix gets into some of the reliability considerations behind the O.Reg. 851 Sections 75 and 76 and CSA Z460 requirements.

Mr Nix posted a second video discussing ISO 13849-1 [5] Category 2 architecture requirements and particularly Testing Intervals. This video explains why it is not possible to meet the testing requirements using a purely electromechanical design solution.

Edit: 16-May-18

A case in the UK illustrates the dangers of bypassing interlocking systems. A worker was killed by a conveyor system in a pre-cast concrete plant when he was working in an area normally protected by a key-exchange system. Here’s the link to the article on Allowing workers into the danger zone of a machine without other effective risk reduction measures may be a death sentence.


[1]     Ontario Regulation 851, Industrial Establishments

[2]     Safeguarding of Machinery. CSA Z432. 2016.

[3]     Safety of machinery — Interlocking devices associated with guards — Principles for design and selection. ISO 14119. 2013.

[4]     Safety of machinery — Evaluation of fault masking serial connection of interlocking devices associated with guards with potential free contacts. ISO/TR 24119. 2015.

[5]     Control of hazardous energy – Lockout and other methods. CSA Z460. 2013.

[6]     Safety of machinery — Safety-related parts of control systems — Part 1: General principles for design. ISO 13849-1. 2015.

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Acknowledgements: Kartik Vashi, ISO, Franklin Empire, S more...
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