Understanding unseen risks in machine safety
By Tyrone Penton
By Tyrone Penton
Nov. 24, 2014 – Finding that fine line between safety and production efficiency is a constantly evolving process. Companies continue to expand their efforts to ensure employee safety and still make gains in their production output.
An ongoing challenge is that often the machine safety is integrated after the machine is built, because risks become much more evident after the fact. This can lead to increased implementation costs and ultimately production downtime.
So how do you go about understanding these risks before the machine is built if they do not immediately jump off the page of the mechanical drawings? It’s all about planning and customizing the safety solution to the machine in the early stages. Understanding which safety products to use for your application can avoid costly changes down the line.
In Ontario, a Pre-start Health and Safety Review (PSR) is a mandatory inspection required for a machine to become operational. In most cases, this is completed by a professional engineer after the machine is built. The PSR could provide a passing evaluation or identify deficiencies that need to be corrected, which can sometimes become much more costly than if they had been addressed prior to the machine being built. Most experienced machine builders work closely with a professional engineer throughout the design process.
We brought in Jim VanKessel, P. Eng., from JVK Industrial Automation Inc., to share some opinions on the most common elements that people forget about when it comes to machine safety. He has been completing PSRs for two decades.
When it comes to machine safety, what are some of the frequently overlooked safety risks that you commonly come across when completing PSRs?
Jim: The most common mistake is the absence of control for the fluid power elements. Everyone gets the electrical interlocks, but then they ignore the risks associated with the air and hydraulic elements. They all agree that the hazard is very serious, but they end up with a general purpose control on the fluid power elements.
Also, robot cells almost never have the restricted space defined, and the robots can reach beyond the safeguarded space. The new robots make defining this space easy, but the end-users don’t understand how much it will help safeguard employees, and they buy the generic robot model instead of the one with the smart safety built-in. In the end, it can cost more to use and safeguard an old robot than it would be to upgrade to a new robot and new safety products.
What tips do you have to help people look for additional safety risks before getting to a PSR?
Jim: The most successful projects are the ones where you can have a discussion up front with a certified engineer. It allows the engineer to do the risk assessment with the designers and end-users, so that when the machine is built, the hazards get addressed properly.
All of the CSA safety standards start with a risk assess ment, but it’s uncommon to find companies doing this as their first step. Typically, they are building the machine to meet production needs and then see the dangers behind it and realize there should be guarding around it. Add-on guards can restrict production, which in turn generates a bad feeling about the safety and may lead to more attempts to disable or bypass the safety in the future. I have been involved in many installations where we ended up changing the process a little so the guard and production can work together. Doing this after can cost big dollars and lead to production downtime.
Completing the risk assessment first will allow you to pick and customize the safety solutions to the machine. Knowing the best safety products for both the obvious and unseen safety risks will help you keep the project on budget and keep your machines running without unnecessary downtime.
Doing a little bit of planning upfront will potentially save you lots down the road, and keep your employees safe while using your machines.
Tyrone Penton is the sales manager at Advanced Motion & Controls Ltd. He has been with the company for 19 years.
This column originally appeared in the November/December 2014 issue of Manufacturing AUTOMATION.