Technical data

Safety Integrated Functions
8.1 Standards and regulations
Function Manual
318 Function Manual, 06/2012, 6SL3097-4AB10-0BP4
8.1.1.2 Functional safety
Safety, from the perspective of the object to be protected, cannot be split-up. The causes of
hazards and, in turn, the technical measures to avoid them can vary significantly. This is why
a differentiation is made between different types of safety (e.g. by specifying the cause of
possible hazards). "Functional safety" is involved if safety depends on the correct function.
To ensure the functional safety of a machine or plant, the safety-related parts of the
protection and control devices must function correctly. In addition, the systems must behave
in such a way that either the plant remains in a safe state or it is brought into a safe state if a
fault occurs. In this case, it is necessary to use specially qualified technology that fulfills the
requirements described in the associated Standards. The requirements to achieve functional
safety are based on the following basic goals:
● Avoiding systematic faults
● Controlling systematic faults
● Controlling random faults or failures
Benchmarks for establishing whether or not a sufficient level of functional safety has been
achieved include the probability of hazardous failures, the fault tolerance, and the quality that
is to be ensured by minimizing systematic faults. This is expressed in the Standards using
different terms. In IEC/EN 61508, IEC/EN 62061, IEC/EN 61800-5-2 "Safety Integrity Level"
(SIL) and EN ISO 13849-1 "Categories" and "Performance Level" (PL).
8.1.2 Safety of machinery in Europe
The EU Directives that apply to the implementation of products are based on Article 95 of the
EU contract, which regulates the free exchange of goods. These are based on a new global
concept ("new approach", "global approach"):
● EU Directives only specify general safety goals and define basic safety requirements.
● Technical details can be defined by means of standards by Standards Associations that
have the appropriate mandate from the commission of the European Parliament and
Council (CEN, CENELEC). These standards are harmonized in line with a specific
directive and listed in the official journal of the commission of the European Parliament
and Council. Legislation does not specify that certain standards have to be observed.
When the harmonized Standards are observed, it can be assumed that the safety
requirements and specifications of the Directives involved have been fulfilled.
● EU Directives specify that the Member States must mutually recognize domestic
regulations.
The EU Directives are equal. This means that if several Directives apply for a specific piece
of equipment or device, the requirements of all of the relevant Directives apply (e.g. for a
machine with electrical equipment, the Machinery Directive and the Low-Voltage Directive
apply).