Machinery Safety 101

Interlock Architectures – Pt. 5: Category 4 – Control Reliable

This entry is part 5 of 8 in the series Cir­cuit Archi­tec­tures Explored

Ed. note: I’ve made a few updates to this art­icle since it was first pub­lished in 2011, with the most recent on 2020-05-11. – DN – The most reli­able of the five… 

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Interlock Architectures – Pt. 4: Category 3 – Control Reliable

Category 3 Architecture Logic Block Diagram
This entry is part 4 of 8 in the series Cir­cuit Archi­tec­tures Explored

This post was updated on 2020-03-28. Cat­egory 3 sys­tem archi­tec­ture is the first cat­egory that could be con­sidered to have sim­il­ar­ity to “Con­trol Reli­able” cir­cuits or sys­tems as was defined in… 

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Hockey Teams and Risk Reduction or What Makes Roberto Luongo = PPE

Canucks Hockey Flag
This entry is part 2 of 5 in the series Hier­archy of Controls

Spe­cial Co-Author, Tom Doyle Last week we saw the Boston Bru­ins earn the Stan­ley Cup. I was root­ing for the green, blue and white, and the ruin of my voice on… 

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New contact block design for Emergency Stop devices from Siemens

This entry is part 9 of 16 in the series Emer­gency Stop

One issue that fre­quently comes up when inspect­ing machinery is the con­tact blocks used on emer­gency stop devices. Until now, e‑stop devices were nor­mally fit­ted with the same con­tact blocks… 

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Why you should stop using the term ‘Deadman’

The Dead­man Con­trol Do you use the phrase ‘dead­man’ or ‘dead­man switch’ when talk­ing about safety-related con­trols on your machinery? I often run into this when I’m work­ing with cli­ents who… 

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Updates to Popular Articles

This entry is part 8 of 16 in the series Emer­gency Stop

We’ve recently updated a couple of our pop­u­lar art­icles! Check them out! Bust­ing Emer­gency Stop Myths Read­er Ques­tion: Mul­tiple E‑Stops and Resets

Reader Question: Multiple E‑Stops and Resets

This entry is part 7 of 16 in the series Emer­gency Stop

I had an inter­est­ing ques­tion come in from a read­er today that is rel­ev­ant to many situ­ations: “When you have mul­tiple E‑Stop but­tons I have often got­ten into an argu­ment that says… 

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Understanding the Hierarchy of Controls

The Hierarchy of Controls illustrated as an inverted triangle with each level of the hierarchy written one above the other, starting with Inherently Sfe design, then Engineering Controls, then Information for Use, then Administrative Controls and finally descending to PPE at the bottom. An arrow with the text "Effectiveness" on it runs parallel to the triangle and points downward from Inherently safe design to PPE.
This entry is part 4 of 5 in the series Hier­archy of Controls

(Eds. note: This art­icle was ori­gin­ally writ­ten in 2011 and was updated in Nov. 2018.) The “Hier­archy of Con­trols” is one approach to risk reduc­tion that has become entrenched in the… 

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Using E‑Stops in Lockout Procedures

This entry is part 6 of 16 in the series Emer­gency Stop

Emer­gency stop devices are some­times, incor­rectly, used as part of a lock­out pro­ced­ure for machinery. Learn more about how to cor­rectly used these devices as part of Haz­ard­ous Energy Con­trol Pro­ced­ures for indus­tri­al machinery.

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Emergency Stop Categories

Emergency Stop on machine console
This entry is part 4 of 16 in the series Emer­gency Stop

I’ve noticed a lot of people look­ing for inform­a­tion on Emer­gency Stop cat­egor­ies recently; this art­icle is aimed at those read­ers who want to under­stand this top­ic in more depth. First,… 

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