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Standards and directives

EC Machinery Directive

Do your products fall within the scope of Machinery Directive 2006/42/EC? Are they intended for the European single market? Then the requirements of the Machinery Directive must be observed.

It is only when these requirements are met in full that machines are allowed to bear the CE mark. This mark is required in order for a machine to be placed on the market and operated in the European Economic Area.

The aim of the Machinery Directive is to reduce the number of accidents that occur when using machinery. This directive therefore requires that the aspect of safety is included in the design and manufacture of machinery.

Manufacturers must also make sure that the technical documentation required by the Machinery Directive has been created. The technical documentation must make it possible to assess whether the machine complies with the requirements of the Machinery Directive.

The manufacturer of a machine or his authorized representative is responsible for creating the technical documents as well as adhering to all requirements.

Important contents of the Machinery Directive:

  • Description of the scope of the Machinery Directive
  • Differentiation from other European directives
  • Definition of complete and incomplete machines
  • Requirements for complete and incomplete machines
  • Requirements and measures for the introduction and startup of machines
  • Meaning of harmonized standards
  • Conformity assessment procedures for machines
  • Procedures for incomplete machines
  • CE marking
  • Essential health and safety requirements for the design and construction of machinery
  • Procedure for the risk assessment of machines
  • Required technical documentation
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EN standards for the safety of machines

Safety standards for machines  

Safety standards for machines

The Machinery Directive contains essential health and safety requirements.
The harmonized standards for the Machinery Directive are listed in the corresponding European Union Gazette.

A machine meets the essential health and safety requirements if it has been manufactured in accordance with these harmonized standards.

The EN standards are divided into various types:

  • Type A – fundamental safety standard
  • Type B – group safety standard
  • Type C – product safety standard

 

Division of the EN standards

Type A

Fundamental safety standards regarding basic concepts, principles for design, and general aspects (for example, design and methodology) that apply to all machines, devices, and systems.

Type B

Group safety standards regarding one safety aspect or one type of safety-related equipment that can be used across a wide range of machines, devices, and systems

  • Type B1 – special safety aspects, such as safety distances and limit values for surface temperatures
  • Type B2 – safety-related equipment, such as emergency stop or two-hand control devices

Type C

Machine safety standards with detailed safety requirements for all significant hazards for a particular machine or group of machines. Type C standards are also often referred to as product standards.

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Harmonized standards for functional safety

Comparison of PL and SIL  

Comparison of PL and SIL

EN 62061 and EN ISO 13849-1 were derived from EN 61508 specifically for the machine engineering sector. Both of these standards specifically address the requirements for safety-related parts of control systems on machines.

Both standards are harmonized for the Machinery Directive and represent state-of-the-art technology. Unlike the previous standard EN 954, these standards can also be applied for complex and programmable systems. In addition, they include all aspects of functional safety derived from EN 61508. It is therefore no longer the case that only deterministic aspects play a role. Furthermore, the statistical probability of failure of systems as well as organizational measures, measures for fault avoidance, and measures for error detection are also important.

The degree of safety is measured in both standards by the level of safety integrity.

EN 62061 uses SIL 1 to SIL 3 and EN 13849 uses PL a to PL e as discrete levels for safety integrity.

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Scope of EN 62061 and EN ISO 13849-1

Why are there two different standards for supposedly the same area of application? You'll find the answers to this question in the table below.

EN 62061EN ISO 13849-1
Simple electromechanical systems such as relays or simple electronics.Simple electromechanical systems such as relays or simple electronics.
Complex electronic systems as well as programmable systems with all architectures.Complex electronic systems as well as programmable systems with planned architectures.
The requirements are specifically designed for electrical control systems. Nevertheless, the defined framework and methodology can be applied to other forms of technology.Can be applied directly for technology outside of electrical engineering, such as hydraulics and pneumatics.
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Safety standard EN ISO 13849-1

Determining the performance level  

Determining the performance level

EN ISO 13849-1 describes the design of safety-related parts of control systems. An important parameter for the reliability of safety-related functions is the performance level (PL).

In order to determine the required PL, various criteria must be assessed: the extent of damage, frequency and duration as well as possibilities for avoiding the hazard.

The following diagram can be used to determine the required performance level (PLr) using these three criteria.

 

Designing and determining the control system architecture

The performance level (PL) of the safety-related part of a control system (SRP/CS) is determined by assessing the following parameters:

  • Category – specified as a defined structure in the standard
  • Mean time to dangerous failure (MTTFd) – specified by the component manufacturer
  • Diagnostic coverage (DC) – can be found in the standard
  • Failure as a result of a common cause (CCF) – to be determined as a point system according to various criteria
  • Achieved performance level (PL) – determined using a table and must be equal to or greater than the required PLr
Determining the performance level
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Implementation of EN ISO 13849-1

EN ISO 13849-1 not only describes the hardware structure of safety-related parts of a control system, but also the software design.

The standard sets out the requirements for the entire lifecycle of safety functions and recommends methods for implementation with configurable safety modules.

Description Language Updated
Implementation of EN ISO 13849-1 [PDF, 0.25 MB]
Here you will find more detailed information on how to correctly implement EN ISO 13849-1.
German 11/01/2010
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Safety standard DIN EN 62061

Determining the safety integrity level  

Determining the safety integrity level

DIN EN 62061 describes the functional safety aspects of safety-related electrical, electronic, and programmable control systems.

An important parameter for the reliability of safety-related functions is the safety integrity level (SIL).

Various criteria are assessed in order to determine the required SIL:

  • Severity of injury (S)
  • Frequency and duration of exposure to the hazard (F)
  • Probability of the occurrence of a hazardous event (W)
  • Possibility of avoiding or limiting damage (P)

 

Designing the control system architecture and determining the achieved level of performance

The safety-related parameter for subsystems is based on the following values:

  • Hardware fault tolerance (HFT), application-specific
  • Safe failure fraction (SFF), manufacturer's information
  • Diagnostic coverage (DC), manufacturer's information or EN ISO 13849-1
  • Probability of a dangerous failure per hour (PFHd), based on the other values
  • Proof test interval or duration of use, manufacturer's information/manufacturer-specific
  • Diagnostic test interval, application-specific
  • Susceptibility to failures resulting from a common cause, manufacturer's information or EN ISO 13849-1
Determining the safety integrity level
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Architecture of the safety function (SRP/CS, SRECS)

  • SRP/CS (safety-related part of a control system)
  • SRECS (safety-related electrical control system)
Architecture of the safety function
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