The Seven Golden Rules for a successful Risk assessment and Risk Reduction

There are about 700 harmonised standards to the Machinery Directive. Few of them, such as ISO 12100, detail how to do a Risk Assessment: Limits of the Machinery, Hazard Identification, Risk Estimation and Risk Evaluation. The majority of them are about how to reduce the risk: the 3 step method.

Technicians and people facing the task of designing a safe machinery may be confused and do not know where to start from. Here you find a list of the most important Type A and Type B standards.

The more standards you know the better, of course. However, it is not enough to know many standards in order to design a safe machinery, you need to have the right mindset: that is why we give you our Seven Golden Rules for a successful Risk Assessment and Risk Reduction Process.

RULE N°1: All your efforts are ultimately aimed at preparing the Technical File. This file contains the evidence demonstrating that your machine is safe. At GT Engineering, we sometimes call the Technical File the “Book of Sins.” During the risk assessment process, you may realize that your machine does not fully comply with all the Essential Health and Safety Requirements (EHSRs) of the Directive.

Welcome to the club: you are not alone.

But do not be discouraged. What matters is that all these “sins” are clearly identified and listed in the risk assessment report. You will find that some of them can be reduced quite easily, while others are more difficult to address and may require a redesign of the machine. We have never seen a CE-marked machine or production line without any “sins.” What is important is to list them in the Technical File, so that you are fully aware of the improvements that need to be implemented in the future.

Remember: machinery safety is not a destination, but a journey.

RULE N°2: Most of the time, you will analyse an existing machine, meaning a machine already equipped with safeguards. When you do the risk assessment on an exiting machine that has several Safeguards like fixed or movable guards, or Laser Scans to detect the presence of a person in a dangerous area, you need to imagine the machine as “naked“, meaning without any of these Safeguards.

RULE N°3: Do not do the assessment on your own. The risk assessment has to be done by a multidisciplinary team that includes the operators, the people who work on the machine every day: remember that we do the risk assessment for them! Being a competent team, there is a high probability that both the risk assessment and the risk reduction are done in an optimal way. You may have played once in the teambuilding activity of Moon Landing. In essence, you have to rank the importance of 15 items you can bring with you, to survive on the Moon. Items rank from a box of matches to two 100 lb. tanks of oxygen. Each team member does its own ranking and, afterward, they have to prepare one common agreed ranking. What comes out, normally, is that the team judgment is better than the one of each member. The same usually happens with the risk analysis we are discussing.

RULE N° 4: Avoid The Glass Dome. In theory, a risk assessment should begin as soon as the machine is conceived. This allows us to fully exploit the first and most important of the three risk-reduction methods: inherently safe design measures, as defined in ISO 12100. In North America, this approach is often referred to as Design Out, or Elimination/Substitution.

If the risk assessment starts while the machine concept is still flexible, there is a real opportunity to eliminate some risks altogether. Eliminating a risk is the most effective way to prevent it from harming a person. Unfortunately, this is rarely the case. In most situations, the risk assessment is carried out after the machine has already been designed, and sometimes even after it has already been built.

The problem is that when safety is addressed only at the end of the development process, the resulting safeguards often restrict how the machine can be used. As a consequence, operators may find the machine difficult or inefficient to operate and may be tempted to defeat or bypass some of the safeguards.

As manufacturers, we should avoid this situation. One way to do so is by implementing appropriate operating modes that allow users to operate the machine safely, even when certain safeguards are temporarily disabled. Examples of appropriate operating modes may include special modes for:

• setting;
• tool changing;
• fault finding;
• maintenance;
• process observation.

These modes depend heavily on the type of machine and its intended application. The key point is that, by following the three-step method of ISO 12100, you should be able to avoid installing what we call the Glass Dome over the machine: a glass dome may make the machine safe, but it also makes it unusable.

Remember: the best safeguard is the one the operator does not even realize is there.

RULE N° 5: the analysis has to be sincere and genuine: people in the team must speak freely without being afraid of being judged. Don’t be afraid to rediscuss an aspect already discussed.

RULE 6: Choose your own format and avoid doing the risk assessment by checking the Essential Health and Safety Requirements. The verification that all EHSRs are satisfied is an important activity but to be done at the end of the risk assessment process. The risk assessment and the following risk reduction are a brainstorming activities and not a check list verification! Do not think that using one of the software available on the market will help you significantly. For sure they will make your analysis look nicer, but if the content you put in is poor, you will end up with a nice cover, but the book content remains poor.

RULE 7: During a risk assessment, you will often face the following question: “Should I reduce this risk by implementing a safeguard, or is it sufficient to address it through the instructions for use, warning the operator about the risk?”

When can machinery truly be considered safe? Have all necessary risk-reduction measures been implemented? Is the risk assessment complete? Is the residual risk acceptable? Is it enough to place a warning next to the hazard, for example a high-temperature warning, or must the risk be reduced by means of a safeguard?

These are difficult questions to answer.

There are many different types of hazards, and often many different opinions on how they should be addressed. For this reason, it is difficult to answer these questions in a purely mathematical way, even when using a risk graph, a risk matrix, or a numerical scoring tool.

For example, should I add a positioning device in the loading area of a transfer machine, or is it sufficient to state in the instruction manual that the operator must use a tool to place the workpiece in the vise?

At GT Engineering, we use the following criterion:

“Machinery can be considered safe when you would feel comfortable having your son or daughter work on it for several years.”

Carry out the risk assessment sincerely, as if your own child were going to operate the machine. When you are comfortable with that idea, the machine you are designing can be considered safe.