Manufacturing AUTOMATION

Stand on guard: Preventing access is key to machine guarding

January 24, 2013
By Franco Tomei

Sections 24 and 25 of the Regulations for Industrial Establishments should be considered the primary but not the only requirements for machine guarding. They read as follows:

24. Where a machine or prime mover or transmission equipment has an exposed moving part that may endanger the safety of any worker, the machine or prime mover or transmission equipment shall be equipped with and guarded by a guard or other device that prevents access to the moving part.

25.  An in-running nip hazard or any part of a machine, device or thing that may endanger the safety of any worker shall be equipped with and guarded by a guard or other device that prevents access to the pinch point.

If we look at these closely, they are general but encompassing. The first thing to note is that there must be exposed moving parts. Secondly, that moving part must be such that it endangers the safety of any worker (and not just the operator). Implicitly, there is the statement that not all moving parts may endanger a worker. Thirdly, the worker is to be prevented from having access to the exposed moving part.


A hazard identification and hazard analysis would be the first step in identifying hazardous circumstances whereby a worker has access to exposed moving parts or nip points that may endanger the safety of any worker.

In any case, what is to be noted is that the provisions place the onus on the employer to prevent access and not on the worker not to gain the access. This is often very hard for many of us to accept simply because, on the surface of it, it would not rational for anyone to do so. But things are not always as they appear and, with a closer look, we must acknowledge that there are various reasons why a worker may reach into these hazardous zones. Some of these are as follows:

• Some people will reach where they should not because in a moment, split-second decisions are made often on emotion (as part of the body’s reaction) and not using rational thinking.

• The worker is not able to perform a specific function without reaching “in there”—the result of poor design.

• The worker believes that the gods (or fate or luck) are on his or her side and somehow feels exempt from a hazardous event or the person simply “knows” what he or she is doing, unlike a person who was injured. The reality is that nobody has a monopoly on errors in judgment—we all make our fair share of mistakes.

• We must also consider the reality of life in that while a worker may be expected to concentrate 100 per cent of the time on the task at hand, a person working eight to 10 hours a day cannot concentrate 100 per cent of the time. Everyday life ensures that we have other issues to deal with (like our finances, marriages, children, aging parents, personal health issues and so much more). How can we reasonably expect 100 per cent concentration 100 per cent of the time?

In analyzing the subject provisions, it becomes clear that the core requirement of sections 24 and 25 is to prevent access. On a personal basis, I often demonstrate to an employer that I have access to exposed transmission elements. The response is like a deer looking into a headlight: “why would you put your hands in there?”

You cannot use whether or not there is an injury as the basis for judging if you meet the standard. Instead, you need to look at whether or not the person has access to an area that has potential for injury.

The purpose of the regulations is to prevent any injury from occurring by preventing the access. Saying “I have been here 37 years and nobody has ever been hurt” is not a defense. The reality is that the absence of an accident does not constitute a safe situation. Sooner or later the hazardous event will occur with the possibility of very serious consequences.

Let’s look at preventing access in more detail. We often see signs posted and the question becomes: “will a sign prevent access?” Of course not. A sign may provide information, but only if it is read. Anecdotally, we have all seen a sign that says “WET PAINT DO NOT TOUCH.” Of course, now we need to ensure the sign is not giving false information and we touch the paint. Since signs do not prevent access, we must resort to engineering solutions that either prevent access to the hazard by virtue of a physical barrier or eliminate the hazard before any worker can gain access (as in the case of providing an interlocking device that signals the apparatus to stop).

Whether or not some of the readers agree with these requirements of these provisions, is not the issue—this is a matter for government policy and the regulators to deal with.

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 article originally appeared in the January/February 2013 issue of Manufacturing AUTOMATION.

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