Using Machine Guards to Improve Industrial Manufacturing Safety
There's no room for error with machine guarding - it's what stands between the worker and the risk of severe injury.
Many of the manufacturing tools, machinery, and processes that are still in use can be traced back decades or even centuries ago. Looking for ways to safeguard workers from the risks associated with using them goes back just as far.
Machine guarding is an important feature of modern manufacturing, but its earliest antecedants came about during the Industrial Revolution of the 1760s to the mid-1850. Concern for worker safety wasn't necessarily at the forefront of the early industrialists' minds, but keeping costs low certainly was. It didn't take long for employers to see that unguarded machines meant damaged products, injured workers, and equipment breakdowns.
In fact, the dangers of unguarded machinery was famously lampooned in an iconic scene from Charlie Chaplin's 1936 film Modern Times.
Despite the centuries of advancements, the modern manufacturing plant is still a risky work environment. Ensuring the safe operation of machinery is unfortunately a perennial problem.
In fact, I've personally seen what happens when industrial machine use goes wrong.
I once investigated a near fatality at a coal fired power plant. A young maintenance worker was literally run through almost a quarter mile of equipment - high-speed conveyor belts, chutes, and other machinery. All of it intended to move coal, not safely transport human beings.
Needless to say, the incident wasn't nearly as amusing as watching Chaplin ride those massive gears.
It also occurred when the worker thought they were safe. A lockout/tagout and safety lock system were in place, but they failed due to operator error during a control room shift change.
(Learn more about Lockout / Tagout in Manufacturing)
The good news is that the worker survived the harrowing experience. The bad news is that he has not, and never will, return to work.
For the company, it meant over a million dollars in workers compensation and medical costs - and that's only for the first year.
Unfortunately, this is the kind of thing that can happen when people and industrial processes meet. And it demonstrates the critical need for controlling the major industrial manufacturing hazards - including the proper use of machine guards.
The Vast Scope of Machine Guarding
Machine guarding is a subject that covers a vast range of equipment.
To get a sense of the scope we're dealing with, let's consider a small subset of industrial machinery. Here are just five basic types of metal working machines:
- Turning machines (all types of lathes)
- Boring machines (including boring mills)
- Milling machines (including saws, gear cutters, and electrical discharge machining)
- Planing machines, (including planers, shapers, slotters, and broaches)
- Grinding machines
Already we're dealing with a variety of complex machines, and this is just a small subset of the entire category.
We can break it down even further by considering the different components of a machine that have to be guarded. Consider, for example, point-of-operation safeguarding for power presses:
- Fixed die enclosure guards
- Fixed barrier guards
- Interlocked press barrier guards
- Adjustable barrier guards
Given that there are literally millions of machines and tools used for industrial manufacturing, hazard identification and analysis remains the best and most basic toolset safety pros have.
Safety Standards for Machine Guarding
When you break it down, all machines consist of three fundamental areas:
- The point of operation
- The power transmission device
- The operating controls
Machine guarding helps protect workers from preventable injuries in all three areas.
OSHA's requirements for machine guarding are found in 29 Code of Federal Regulations (CFR) 1910 Subpart O. It covers, among other things, the identification of hazardous mechanical actions and motions, shown in the following table.
|In-running nip points||Punching|
Standards by ANSI and CSA also speak to machine guarding. So does ISO 14120:2015. In fact, all the OHS legislation and standards I have ever read has included regulation covering machine guarding.
Designing Machines for Safety
Across standards and guidelines, you'll also find significant reference to the importance of design safety when it comes to industrial machines. Hazard identification and machine guarding should be part of the very first steps of the process - all the way back to the manufacturing of the machines themselves.
The standards provide a number of questions that engineers need to ask themselves:
- Do the designs prevent workers’ hands, arms, and other body parts from making contact with dangerous moving parts? (OSHA 1910.212(a)(3))
- Have we identified and met all the requirements of the ANSI machine guarding standards?
- Will the design properly address point-of operation exposure? (OSHA 1910.212(a)(3))
- If robots are to be used, are they designed to ANSI/RIA R15.06-1999 standards?
Anyone involved at the design stage should consult the Design Safety Checklist from the National Safety Council Accident Prevention Manual: Engineering and Technology (13th edition). Like any checklist, it's not all-inclusive, but it's a great refresher, eye-opener, and will encourage some positive safety thinking.
While there are many steps that need to be taken by the end user, the legislation and standards place the brunt of the responsibility for machine safety on the manufacturers. That makes them an important ally in keeping your facility safe. Not only because you have to rely on them to produce safe equipment, but because they are your best source of information and assistance when it comes to running them safely.
Take advantage of their expertise. Communicate your organization's needs to the manufacturer and outline how you'll be making use of their machinery. Make this part of your due diligence and ensure that it's done before anyone even turns the machine on.
Guarding to Protect Machinery
Machine guarding is, first and foremost, about preventing injury to workers.
There is another side to it, however. Guarding is also an effective way of protecting the machines themselves.
Machine guards can protect equipment from impact damage. It can also keep dropped objects from falling into the machine's moving parts.
While not a direct risk to employees, preserving the integrity and functioning of the machinery should be included in your hazard identification and analysis, as well as your safety inspections.
Use Guards Only as Intended
This might be stating the obvious, especially to an audience of safety professionals, but the guards should only be used as specified by the manufacturer.
Modifying or removing machine guards and any other safety device is ill-advised. Guards are precisely and carefully designed and crafted to provide effective hazard control. Any changes made to them could have disastrous results - even if it still seems to work fine. On top of that, tampering with the guard places your company under liability.
If you're tempted to modify or remove a guard, consult the manufacturer first. Only proceed if they advise you to do so.
Other Essential Safety Measures
Guarding is, of course, only one component of machine safety.
Securing the Equipment
Placing and securing industrial manufacturing equipment is another important consideration. Finding a stable spot for the machinery and securing it properly is critical - the sheer weight and size of this kind of equipment needs foundations and mountings that are equal to the task.
Anyone who has ever seen something weighing more than a ton tear loose from its moorings knows that this is a step to take very seriously.
A robust maintenance program is essential as well. Even a brief analysis of industrial incidents shows that servicing and maintaining manufacturing machinery is a major factor in preventing worker injury and equipment damage.
The idea behind machine guarding is simple: separate the worker from the machine's hazards.
Although it's simple, it should not be taken lightly. Failure comes at a monstrous cost. Without the right protection in place, industrial machines injure, maim, and kill. We're talking about crushed fingers, amputated limbs, and other traumatic injuries - and that's only if the injured worker is lucky enough to survive the accident.
That kind of severity should get our attention. This is 2022 and we're safety professionals. We have the knowledge and technology to make the workplace safer than ever - even when powerful machines are involved.
As my friends from Newfoundland say, “best get after it.”