vrijdag 11 oktober 2019

Safe machinery, step-by-step

From risk assessment to CE marking

Machine manufacturers are obliged to carry out the conformity assessment procedure on their machines. By affixing the CE mark the manufacturer confirms that plant or machinery meet all the essential health and safety requirements of the Machinery Directive 2006/42/EC. There are 8 steps to master en route.

The Machinery Directive is the benchmark for the safety of plant and machinery within the EU. It specifies a standardised level of safety, guaranteeing the free movement of goods.

Step 1: Risk assessment as the key to machinery safety

The risk level is calculated based on the probability of occurrence and the potential severity of injury.


Step 2: Develop the safety concept

The safety concept takes into account, for example, the use of fixed and mobile safeguards, systems for stopping plant and machinery, options for switching off the electrical energy safely, as well as liquids and gases under pressure, and the detection of workers within danger zones.


Step 3: Safety design and selection of components

The aim of the safety design is to reduce or eliminate danger points through detailed planning of the necessary protective measures. This applies whether the machine is to be built from new, retrofit or converted. Specifically it concerns the design of the mechanics, electrics, electronics, software and control systems, plus the selection of components.


Step 4: Correct selection of safety components

In order for the correct components to be selected, it is necessary to determine and verify the Performance Level (PLr) or Safety Integrity Level (SIL) that is to be achieved in accordance with EN ISO 13849-1 / EN IEC 62061. Corresponding calculation tools provide support for this complex procedure. Based on the safety-related characteristic values of the components that are planned or used, the PASCAL Safety Calculator from Pilz validates the values that have been achieved, including the required or demanded default values PLr or SIL. The advantage of software-based tools is that they guide you step-by-step through the individual stages involved in validating safety functions.


Step 5: System integration

Step 6: Risk assessment review

The risk assessment review re-examines the steps taken previously: Have the protective measures been implemented correctly? Has safety been designed correctly in association with the machine control system and has it been implemented in accordance with the safety regulations? Validation is essential for proving that machines are safe. The review also includes function testing and fault simulation on the safety system, as well as various measurements (protective earth conductor, noise emissions, ...). The results are to be recorded and documented.


Step 7: Operating instructions

Safety guidelines are a key element in all operating instructions. According to legislators, safety guidelines must describe all the residual risks from hazards after protective measures have been applied. Machine builders must also take into account the risks that could arise from any "reasonably foreseeable misuse" of the machine on the part of the user. So a careful risk assessment is a good basis on which to produce the operating instructions.


Step 8: CE certification

By attaching the CE mark to his product, the manufacturer or the person placing the product on the market is ultimately confirming that his product meets all the legal requirements of the Machinery Directive 2006/42/EC and conditions in terms of its assured properties and when used in accordance with its intended purpose. All machinery imported from non-EU countries also require a CE mark, irrespective of the year of construction. Attaching a CE mark is the sole responsibility of the manufacturer/person placing the product on the market and does not require any official approval.

If individual machines that are already CE-certified are joined together to form an assembly of machines (plant), the conformity assessment procedure, including CE marking, must be carried out for the entire plant.