Machine safety and risk analysis

A few weeks ago, a machine safety training took place in our company. Daniel Szeląg, our Head of the Automation and Mechanics Department, summarizes why, as a manufacturer of machines, we are obliged by the law in Poland to build them in accordance with the guidelines of the European Union, of which Poland is a member. Meeting these requirements entitles us to issue appropriate documents for the machine (e.g. EC Declaration of Conformity) and mark the machine with the CE mark.

Directives-What is a directive and what directives do our machines meet?

A directive is a legal act setting out the objectives (main guidelines) that must be met on a machine in order to be considered safe for the user and to be placed on the market. The main directives that our machines must meet are:

• Machinery Directive (MD) - 2006/42 / EC
• Low voltage electrical products (LVD) - 2014/35 / UE
• Electromagnetic Compatibility (EMCD) - 2014/30 / EU
• Restriction of Hazardous Substances (ROHS II) - 2011/65 / UE

In special cases, other directives may also apply, e.g. Equipment for use in explosive atmospheres (ATEX) 2014/34 / EU.

Standards-What are harmonized standards machines?

Harmonized standards supplement the directives. They contain detailed solutions to specific issues and "good practices", the application of which in practice will allow us to recognize the machine as safe. There are three types of standards (A, B, and C) divided depending on the degree of detail in the "issues". The most detailed standards - type C, contain guidelines on how to solve safety problems on specific machines (e.g. grinders: PN-EN ISO 16089: 2016-04 Machine tools. Safety. Stationary grinders). Type B standards include general solutions for pneumatics, hydraulics, and electrics, as well as specific safety elements (e.g. the "electrical" standard PN-EN 60204-1: 2018-12 Safety of machinery. Electrical equipment of machines. Part 1: General requirements). Type A standards are the least detailed standards and contain the most important concepts and general aspects of machinery safety (PN-EN ISO 12100: 2012 Safety of machinery. General principles for design. Risk assessment and risk reduction).

EC declaration of conformity-On what basis do we issue the EC declaration of conformity?

By issuing an EC declaration for each newly built machine, we confirm that the machine is manufactured in accordance with the relevant harmonized standards. Seeing this assurance from the manufacturer, the user has grounds for presuming compliance with the standard and, consequently, for proper protection of the machine.

Presumption of compliance with the standard is the method most often used by manufacturers to issue an EC Declaration of Conformity and thus to mark the machine with the CE mark. Another way is to refer to your knowledge and experience in the declaration, and another way is to invite a notified body to assess the safety.

Risk analysis-What is a risk analysis, how is it done?

The level of user protection and the selection of specific security measures is determined based on the risk analysis performed. This analysis determines the primary risk that occurs on the machine before the application of all safeguards and the residual risk that remains on the machine after using all available safety measures. This is an acceptable risk that the user must be made aware of in the machine manual.

Safety measures that must be applied on each machine are (in the order of their application):

• Construction elements (designing and manufacturing a machine that is safe by design),
• Technical safety measures (guards, safety switches, two-hand control buttons, light curtains, security scanners, etc. - used where the hazard cannot be eliminated by the structure itself),
• Information about the residual risk (pictograms, description in the operating manual, etc.).

The need to implement any security measure and the level of security starts with identifying the hazards on the machine. Several methods are used to identify the risk, the most frequently used in our case are Risk Score and PHA. Both of these methods are based on determining the level of threats using parameters such as:

• The extent of the damage that a given threat may cause,
• Exposure (frequency and duration) of exposure to the hazard,
• The possibility of a threat,
• The possibility of avoiding the risk.

Using the above parameters, for each hazard, a risk level indicator is determined, which by applying further safety measures (design -> technical -> residual risk information) is minimized - to an acceptable level.

The risk analysis should be carried out for each stage of the "life" of the machine (assembly and installation, handover, operation, disassembly).

Threats-What are the threats to the machines?

The hazards that may appear on machines are described in the EN ISO 12100 standard, which divides them into several basic groups:

• Mechanical hazards (e.g. crushing, crushing, entanglement, puncture, puncture, drawing-in, entrapment, etc.),
• Electrical hazards (e.g. burns, burning, electric shock, etc.),
• Thermal hazards (e.g. burns and burning, frostbite, dehydration, etc.),
• Noise-related hazards (discomfort, unconsciousness, fatigue, stress, tinnitus, hearing impairment, etc.),
• Vibration hazards (e.g. neurological disorders, back injuries, lumbar disorders, etc.),
• Radiation hazards (eye damage, skin injuries, burns, genetic mutations, etc.),
• Risks related to materials and substances (breathing difficulties, asphyxiation, cancer, poisoning, etc.),
• Risks caused by failure to take into account the principles of ergonomics in the design of machines (fatigue, stress, disorders of the musculoskeletal system, etc.).

 Documentation-What documentation do our machines have?

The process of implementing the machine into production is completed by handing over the documentation to the customer. In the case of our company, this documentation includes:

• Operating instructions for the machine (with information on residual risk),
• Electrical, pneumatic, and possibly hydraulic diagrams,
• Certificates of electrical and noise tests,
• Certificates of measuring equipment (force sensors, displacement sensors),
• EC Declaration of Conformity or (in the case of a partly completed machine, Declaration of Incorporation of the partly completed machine),
• Other required documents specific to a given machine or customer.

The manufacturer is not obliged to provide the customer with the risk analysis itself. However, it very often includes the requirement to provide this document in the terms of the contract, which obliges us to hand it over upon receipt of the machine.

All documentation must be kept by the manufacturer for at least 10 years after the device was manufactured.

Author: Daniel Szeląg