Although the consequences of inadequate machine safety practices can be severe, there are nonetheless several misunderstandings in existence that put many facilities and their employees at risk. Omron, which assesses and evaluates over 3000 machines a year across the world, has seen the ways in which a lack of safety knowledge can lead to poorly functioning safety systems.
Omron found that misconceptions about machine safety are currently on the rise as older, experienced workers are retiring in large numbers, with few mid-career workers inheriting their expertise. This trend is causing many industrial facilities to lack the engineering expertise required to ensure that their machines meet modern safety standards. In addition, an increase in the prevalence of newer, fully automated solutions may in some cases lead to complacency, as manufacturers mistakenly believe that their new systems must be compliant –bringing us to our first safety myth.
Myth 1: If a machine is brand new, then it must be compliant
This is false. Safety usually isn’t a core competency of OEMs, so they avoid designing safety solutions that they have little expertise with. All of this means that safety measures have become the responsibility of the end user.
Manufacturers worry that safety measures hamper productivity and make processes less efficient. Although it is true that safety systems can slow down some processes, their benefits far outweigh the costs. When it comes to costs, safety measures save money in the long run by helping to avoid expensive, traumatic incidents.
Myth 2: Safety is too expensive and reduces productivity
The cost of an accident demonstrates the falsehood of the above statement. These costs include not only fines and worker’s compensation, but also loss of productivity due to poor morale.
To address the effect of safety measures on overall productivity, it is important for manufacturers to note that safety measures can be designed in ways that do not hamper the efficiency of the machine. An example would be an application that uses a safety laser scanner to minimise downtime in areas with collaborative robots (cobots). In this scenario, if a worker enters the robot work area, the safety laser scanner will trigger the cobot’s reduced speed mode and will cause it to slow down to a safer operating level. When the employee steps out of the area, the cobot will go back to its faster speed.
Myth 3: Good administrative control and comprehensive employee safety training can replace good engineering
The foundation of machine safety consists of a hierarchy of controls (in the USA this is published by the National Institute of Occupational Safety and Health, or NIOSH) which lists administrative controls and personal protective equipment as the least effective ways to mitigate risk. Physically removing the hazard (elimination) and replacing the hazard (substitution) are the most effective measures, but these can be impractical.
Engineering controls form the middle ground for protecting operators from hazardous machine motion.
Myth 4: Older machines can be ‘grandfathered’ in, so they don’t need safeguarding
No, equipment is not exempt from current machine guarding standards, and so-called ‘grandfather clauses’ simply do not exist for machine safeguarding. An exemption does exist under some robot standards, and it applies to a robot’s safety circuit integration. This very narrow exemption has led to some confusion as manufacturers mistakenly interpret it to apply more generally.
The underlying reason for the resistance to retrofitting legacy equipment with current standards-compliant safeguarding is the cost. This concern also relates to another misconception that exemptions exist when there are none, this time with regard to smaller companies.
Myth 5: There are machine safeguarding exemptions for smaller companies
This is false. All companies are required to safeguard their machines properly and protect the lives and safety of their employees. What may depend on company size is the amount that a company is required to pay in case of a safety violation.
In general, regulatory agencies see enforcement actions as serving to motivate compliance, rather than simply functioning as punitive measures. Regulatory bodies often have discretion as to the nature and size of an enforcement action – they can issue a warning or a fine, or in extreme cases, lock out non-compliant equipment.
Myth 6: When several machines are identical, it is only necessary to do a risk assessment for one of them
This is not necessarily true; it depends on the complexity of the machine. Even seemingly insignificant differences between machines, and their positioning relative to one another, could change the outcome of the risk assessment. For example, the addition of a small step to one of several otherwise identical machines could be sufficient to place a worker in harm’s way.
Myth 7: If a machine was assessed for risk before it was moved to a new location, there is no need to do another risk assessment
As with the previous myth, this depends on the complexity of the machine. Moving it to a new location could create a requirement for a new risk assessment.
When assessing access to a hazard on a machine, Omron’s safety experts use a system known by the acronym ‘AUTO’ to determine whether an employee can reach around, under, through or over a safeguarding measure to reach the hazard area.
When a machine is first assessed in its original location, there may be a wall or another structure blocking access to part of it. Once it is placed in a new location, the immediate surroundings may not block access in the same way, giving employees unrestricted access to the hazard.
Myth 8: A gate using a padlock to prevent access in an acceptable and sufficient safety measure
This is false. Movable guards providing protection against hazards need to be interlocked to signal the apparatus to stop. Fixed guards should be securely held in place, either permanently (by welding, for example) or by means of tamper-resistant fasteners that make it impossible to open the guards without using tools that are not readily available to operators on the manufacturing floor.
Myth 9: Performance requirements for safety measures stop at the wire
This misconception has to do with the ways in which various energy sources must be safeguarded. Many manufacturers believe that safeguarding is only necessary when the energy source is electrical. As it turns out, all hazardous energy sources need to be ‘single-fault tolerant’, including hydraulic and pneumatic sources.
Myth 10: Safety is something you can just take care of once and forget about
Safety is an ongoing requirement, and companies must have regular risk assessments performed on their machines to ensure that that they meet the most recent safety standards. Standards evolve, with the purpose of making workplaces safer, and it is imperative for manufacturers to stay up to date and protect employees.
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