Last edit: 05/01/2024
There are about 700 harmonised standards to the machinery directive. Few of them, like ISO 12100, are about the risk assessment; the majority of them are about how to reduce the risk.
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.
But, most important, in order to design a safe machinery, you need to have the right mindset: that is why we give you our seven golden rules.
RULE N°1: We call the Technical File the Book of Sins. When you do a risk assessment you realise you do not comply with all the Essential Health and Safety Requirements of the Directive: welcome in the club! Don’t be discouraged: just list all the “sins” in the risk assessment report. You will realise some of them can be easily reduced, while others are more difficult and require a redesign of your machine. We have never seen a CE marked machine or production line without sins!
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 you need to imagine the machine as “naked“.
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. The risk assessment starts when the machine is conceived, so that especially the first step of the Risk Reduction method can be maximised: the use of inherently safe design measures (ISO 12100), also called Design Out (Elimination or Substitution) in North America. Unfortunately, that is rarely the case. The issue is that, when approaching safety at the end of the development process, we tend to use safeguards that limit the machine usage. For that reason, the operator may have difficulties in using the machine, and he is prone to defeat some of the safeguards. As a manufacturer, we should avoid that situation, for example, implementing Appropriate Operating Modes that allow the user to operate the machine in a safe way, even with some safeguards temporary disabled. Appropriate operating modes can be, for example, a special mode for setting, tool changing, fault finding, maintenance, or process observation. They depend highly on the type of machine and its application. The bottom line is that, by following the 3-step method of ISO 12100, you should be able to avoid installing what we call the Glass Dome on the machine: a Glass Dome makes the machine safe but unusable! Remember that the best Safeguard is the one the operator does not realize it 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. That is an important activity but to be done at the end of the risk assessment. The risk assessment and the following risk reduction are a brainstorming activities and not a check list verification!
RULE 7: But when can I consider the machinery safe? Did I do all the needed risk reductions? Am I finished with this activity? Is that specific risk, still left, acceptable? Is it enough to place a warning next to the hazard (for example a High Temperature) or do I need to reduce it with a safeguard? Those are difficult questions to answer! There are so many types of hazards and so many opinions in the team that it is difficult to answer to that question mathematically, even when using a risk chart or a risk matrix or even a numerical scoring tool! Shall I add a positioning tool to the loading area of a transfer machine or I can write in the manual that the operator must use a tool to place the workpiece in the vise?
In GT Engineering, we use the following criteria:
“The machinery is safe when you would be comfortable in having your son or your daughter working on it.”
Do the risk assessment sincerely, thinking that your offspring will work on it. When you are comfortable with that idea, the machine you are designing can be considered safe.