Manufacturing AUTOMATION

Evaluating the incentive to defeat protective devices

June 21, 2012
By Franco Tomei B.A.Sc. P.Eng

Many enterprises seem to accept the high risk generated by defeated protective devices placed on machinery.

By “defeated,” I mean safety devices that have been altered so as to render their intended function ineffective. There are also safety integrators that install protective devices that render the machine unusable. While this may sound far fetched, I have, on at least two occasions, been called upon to review machinery that became unusable because of the protective devices.

Use of protective devices on machinery is necessary to protect the worker. If the moral obligation isn’t enough to ensure their effectiveness, there are regulatory requirements that must be fulfilled. Yet, many workplaces end up with machinery whereby defeating the protective device is part of a company’s everyday life.

Time and again, defeated protective equipment causes severe injuries and, in some cases, fatalities. From a realistic viewpoint, it must be stated that defeating protective devices could not happen if there was not some willingness on the part of the employer/supervisor to permit the defeating to happen. Rather than criticize these actions, we must refrain from placing blame and learn why such actions take place. If we can learn the why, we may be able to prevent the defeating of safeguards.


Given that a worker is a rational, thinking person, defeating a protective device for no reason simply would not occur. Similarly, given that the employer is a rational, thinking person, he or she would also not permit the defeating of protective devices. To get to the root of the problem, it must be concluded that the defeating takes place because there is something to gain — whatever that gain may be perceived to be by either party.

In a study conducted in Germany, it was found that 37 percent of protective elements were defeated. In presenting this study a few years ago in Mississauga, Dr. Friedrich Adams of Schmersal GmbH did not call for greater enforcement, nor did he place blame on the employer or worker. Rightfully, in my opinion, Dr. Adams stated that we as machine builders or safety integrators have failed in our mission to the worker and the employer. We have failed because we have created the conditions such that the performance of a task is so inconvenient or cumbersome that we are providing an incentive to the worker and/or employer to defeat the protective device.

As a sidebar, it is worth noting the variance in the approach to safety of machinery in Canada compared to the European Free Trade Association (EFTA). In the EFTA, the machinery must be deemed to meet the Machinery Directive of the EU before it can be placed on the market. Successfully meeting the Machinery Directive causes the machine to be declared safe. As far as I am aware, in Canada, the responsibility for the safety of the machine is placed on the employer, who should ensure the safety of the machinery through commercial contracts. These two fundamental approaches on how machinery is placed on the market result in different methodologies in seeking solutions.

If defeating the protective device is foreseeable, the manufacturer and/or safety integrator has to take this into account at the design stage or during the retrofit. Essentially, as designers/users, we know the tasks that are to be performed on the machine. Once the tasks are identified, we need to ensure the worker is protected in the course of performing each of those tasks, but we must do so without any significant “inconvenience” to the worker or process. If the protective device creates an “inconvenience,” then the first thing that will be done by the individual worker or in collusion with others and with the blessing of supervisors/employers, is the protective device will be defeated — and sooner or later this will result in an injury.

In the machinery industry, the manufacturer of the machinery and the user of the machinery should have a collaborative program whereby information is exchanged to ensure there is no task whereby there is a significant incentive to defeat the protective device. This would assist the manufacturer in seeking solutions to prevent such events.

How can one assess whether or not their own machinery’s protective devices are defeated? Several tools can be used, such as supervisory inspections of the protective devices, reports from the manufacturers (although not common), and asking the worker for input on the adequacy of the machine in performing their work. However, the better approach is to, at the design stage, assess whether or not there is a foreseeable significant enough incentive for a protective device to be defeated in performing a specific task.

Assessing whether or not a safeguard will be defeated is not insurmountable. The steps necessary to do so are as follows:
• Identify each activity required for the machine;
• Break the activity down into the various tasks; and
• For each task, assess whether or not the task needs to be performed with a protective device to protect the worker.

Assess whether there is a significant enough incentive to defeat the safeguard by considering the following 11 common incentives:
1) Will defeating the safeguard make the job easier or more convenient?
2) Will defeating the safeguard result in faster and/or greater productivity?
3) Will defeating the safeguard result in increasing the capacity of the machine?
4) Will defeating the safeguard result in greater precision?
5) Will defeating the safeguard result in better visibility?
6) Will defeating the safeguard result in better audibility?
7) Will defeating the safeguard result in less physical effort?
8) Will defeating the safeguard result in reduced travel?
9) Will defeating the safeguard result in greater freedom of movement of the worker?
10)  Will defeating the safeguard result in material flow improvement?
11)  Will defeating the safeguard result in avoidance of interruptions?

The above questions could be answered with a straight yes or no, but life is never that simple as there are degrees of incentives. It is therefore recommended that a score be given to each of the questions, whereby an acceptable number is defined. In addition, one should also look at the greater picture since, while all of the answers may be low enough to be a no, the total may result in a yes.

Where the answer is yes, action must be taken on the possible various fronts that will permit the worker to perform the task without having significant incentive to defeat the protective device.

Franco Tomei, B.A.Sc. P.Eng, is a professional engineer with more than 40 years of industrial experience — 12 years of that directly in the safety field. He can be reached at This column originally appeared in the June 2012 issue of Manufacturing AUTOMATION.

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