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
Machine
manufacturers have an obligation to supply only safe products to customers in the internal European market.
So under
the terms of the Machinery Directive, a machine manufacturer must carry out a
risk assessment. The risk assessment should include
identification of the applicable harmonised standards and regulations,
determination of the machine's limits, identification of all the hazards in
each of the machine's lifecycle phases, actual estimation and assessment of the
risk, plus the recommended approach for reducing the risk.
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 describes the technical measures and guarantees the safety of
your machinery in accordance with national and international harmonised
standards. A good safety concept will resolve the recurring conflict that
arises between safeguards
and productivity.
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
The
selected safety measures are implemented based on the results from the risk
assessment and safety concept. This includes collaboration
with and selection of appropriate suppliers, acquisition of components and
implementation of system solutions, configuration of control systems and
creation of visualisation interfaces, electrical installation of plant and
machinery, mounting of mechanical protective measures and hydraulic components,
assembling and testing control cabinets and training of machine operators and
maintenance staff.
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
Operating
instructions are an integral component in the supply of plant, machinery and
products. Any error in the operating instructions can have legal consequences
if the error leads to an accident.
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.
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