Machinery Safety 101

Trapped Key Interlocking

This is a trapped key interlock on the door of an electrical switchgear cabinet. To open the door the key must be inserted and turned to withdraw a bolt that holds the door closed. With the bolt withdrawn, the key is held in the lock. The upstream switching device is held open by another interlock using the same key; since the key can only be in one of the two locks, it prevents accidentally closing the upstream switch while the cabinet is open for maintenance. The interlock is attached to the door with one-way screws to discourage casual removal of the lock, which would defeat the system.
This entry is part 3 of 7 in the series Guards and Guard­ing

Many machine design­ers think of inter­locks as exclus­ively elec­tric­al devices; a switch is attached to a mov­able mech­an­ic­al guard, and the switch is con­nec­ted to the con­trol sys­tem. Trapped Key Inter­lock­ing is a way to inter­lock guards that is equally effect­ive, and often more appro­pri­ate in severe envir­on­ment­al con­di­tions. Copy­right secured by Digi­prove © 2018Acknow­ledge­ments: As cited.Some Rights ReservedOri­gin­al con­tent here is pub­lished under…

Five reasons you should attend our Free Safety Talks

Banner for the 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…

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Presence Sensing Devices – Reaching over sensing fields

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.…

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CSA Z432 Safeguarding of Machinery – 3rd Edition

If you build machinery for the Cana­dian mar­ket, or if you modi­fy equip­ment in Cana­dian work­places, you will be famil­i­ar with CSA Z432, Safe­guard­ing of Machinery. This stand­ard has been around since 1992, with the last major revi­sion pub­lished in 2004. CSA has recon­vened the Tech­nic­al Com­mit­tee respons­ible for this import­ant stand­ard to revise the…

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Get the Basics Right!

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…

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New HSE advice on CE marking assemblies of machinery

Guarded machinery in a plant

This post was ori­gin­ally pub­lished on machinebuilding.net. Reprin­ted with per­mis­sion. By Jon Severn, machinebuilding.net A degree of con­fu­sion sur­rounds the ques­tion of CE mark­ing assem­blies of machinery under the Machinery Dir­ect­ive 2006/42/EC. To help cla­ri­fy the situ­ation, the HSE (Health and Safety Exec­ut­ive) has pub­lished a new page on its web­site entitled­In situ man­u­fac­ture or assembly of work…

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Interlocking Devices: The Good, The Bad and the Ugly

This entry is part 1 of 7 in the series Guards and Guard­ing

Note: A short­er ver­sion of this art­icle was pub­lished in the May-2012 edi­tion of  Man­u­fac­tur­ing Auto­ma­tion Magazine. When design­ing safe­guard­ing sys­tems for machines, one of the basic build­ing blocks is the mov­able guard. Mov­able guards can be doors, pan­els, gates or oth­er phys­ic­al bar­ri­ers that can be opened without using tools. Every one of these guards…

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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 Thursday was ample evid­ence that no amount of cheer­ing helped. While I was watch­ing the game with friends and col­leagues, I real­ized that Roberto Luongo and Tim…

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 Occu­pa­tion­al Health and Safety (OHS) sec­tor. There are oth­er approaches to risk reduc­tion which are equally effect­ive but are less rigidly struc­tured. If you…

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