The general perception of machine safety is that it makes the machines stop. Not so, said Pat Barry, a regional marketing leader for Rockwell Automation. “If that were true,” he said, “it means the safest companies would be the least productive. World-class safety, companies have the best safety performance and the best production performance.”
Barry, speaking to a crowded room at the America’s Safest Companies Conference in Atlanta on Oct. 29, said that at its most basic form, machinery safety is “how we keep people safe around machines.” However, he added, appropriate machinery safety does more than keep employees safe.
“Let’s talk about safety and productivity and how those two meld with each other,” Barry suggested. “The fact is, if we have that good, collaborative process (between EHS and production) and we use a good safeguarding process, we can make decisions that will effect both safety and productivity but we have to be deliberate about it. It can’t be a mistake.”
He said that basic machine safeguarding concepts can be boiled down to two basic rules that can be used to keep people safe around machines: Rule No. 1, if you’ve got to get at a machine, shut it off. Rule No. 2, if it’s running, keep people away from it. And, he added, there are federal regulations related to both of these concepts: lockout/tagout and machine guarding.
“When you put those two tools together what we have is a perfectly safe machine that nobody can use, right?” Barry asked, to some laughter from the audience. “We can guard the crap out of it and make sure we lockout/tagout … but then somebody wants to do something silly, like load parts.”
Because in some cases, employees in and around operating machinery, the minor service exception was created. This exception is used in cases where there is a specific set of tasks that are routine and repetitive and they have to be done to keep production running.
In some cases, lockout/tagout – shutting the machine down completely – is an appropriate safety measure. In others, such as those covered by the minor service exception, alternative measures might be the best solution.
As Barry described it, lockout/tagout is an active solution. An employee has to take the steps to shut down and lock out the machine. Alternative measures can be passive, or, as Barry said, “Take what person is doing on the machine anyway and use that to trigger the safeguard.”
As an analogy, he explained that an active safety measure is a seatbelt: you have to place it around your waist and secure it and adjust the shoulder strap. An alternative, passive safety measure is an airbag. All you have to do to trigger it is sit in the seat – something you were going to do anyway.
Are Passive Measures More Protective?
Showing a slide (below) of two workers engaged in what obviously are dangerous activities, Barry asked if anyone had seen anything like that at their facilities and said, “When people work around machines every single day, they get complacent. They think they can predict how the machine is going to work and they do things like that when they get a jam. Things don’t happen frequently with machines, but when they do happen, they’re generally pretty bad.”
He said that in his opinion, there is nothing else that you can touch as EHS professionals that will effect productivity the way machine safety will.
“We fight this perception that safety is a cost,” he said. “When we start talking about enabling people to do their jobs or streamlining the process or doing things faster, then we can start talking about safety as a productivity enhancement, not just a cost.” Three things where facilities typically find productivity improvements, he added:
- Design things out of the system that cause delays (either an element of the process that is inefficient or a material in the production process that causes delays).
- Get more information to an operator so that they can find a problem faster and fix it faster.
- Use alternative methods of control instead of lockout/tagout.
According to Barry, the machine safety lifecycle has five steps:
- Step 1: Risk or hazard assessment
- Step 2: Safety system functional requirements
- Step 3: Safety system design and verification
- Step 4: Safety system installation and validation
- Step 5: Maintain and improve safety system.
He said that manufacturing facilities that want to implement a machinery safety process need to start out with a good risk assessment, and that risk assessment first needs to address employees, and what they’re doing with the machinery – the tasks they are performing and the hazards they encounter as they are performing them. Rate the risk and choose and design a safeguard to match that risk.
Facilities need to go through a prioritization process. “You can’t do everything at once,” Barry said.
Barry used a slicer at a food processing facility as an example, focusing on how the operator interacts with the machine. “If you’re not looking at how the person interacts with the machine, you’ll make a mistake – absolutely guaranteed,” said Barry. “I’ve seen it a thousand times. If you put the wrong safeguard on there and it doesn’t matter how good or tamperproof it is … the operator who spends eight or 10 hours a day on that machine will absolutely find a way to defeat it.”
In the scenario created by Barry, the unsliced product goes in on one end, is sliced in the middle of the machine and comes out on the other end. Three times an hour, an employee must clean the cutting section. The hazard of that task is that an unexpected start might cause the employee cleaning the machine to suffer a serious cut or amputation injury. Perhaps the current safeguard on that machine is lockout/tagout.
So, this is a risk of serious injury with a frequent exposure and since employees can see the risk (the cutting area), so they can avoid it. When you decide to address the hazard, these questions should be asked:
- Can the hazard be designed out? (Most effective)
- Can a fixed enclosing guard eliminate or neutralize the hazard?
- Can monitoring access/interlocked gates be utilized?
- Can awareness means, training and procedures eliminate the risk of injury? (Administrative)
- Can personal protective equipment protect employees from the hazard? (Least effective)
Barry said that the mistake made by many companies is that instead of identifying how employees interact with machines, they conduct a guard audit, to ensure that guards are in place and are fixed properly “and the first time someone has to clean that machine, the guard is taken off and sits next to that machine” from that point forward.
Instead, said Barry, look at alternative solutions that prevent access. You can use presence-sensing devices to detect that someone has entered the safeguarded area and it shuts of the machine. Or, you can fix the position of the operator; the positioning and design of controls prevents operation while the operator is exposed.
Finally, you can fix process conditions by controlling and monitoring the speed of the operation. Calling this solution “pretty sophisticated,” Barry noted that if the rollers spinning one way on the machine causes a pinch point, spinning them the other way eliminates that pinch point. The process is monitored to ensure the machine only spins in the direction that does not create a pinch point.
The most important thing to remember when using a safeguard is that it is valid for that task, said Barry.