Machine Safety FAQs
These are the questions that are answered on the page below. Click a question to be taken to the answer, or browse down the page to read all FAQ's.
Questions (click for answer)
Q. Why change?
A. There are several reasons for change;
A. Now that BS EN 954-1 will be withdrawn 29 December 2009, the available alternatives are BS EN 62061 and BS EN ISO 13849-1.
The performance of each safety function is specified as either:
BS EN ISO 13849-1: “Safety-related parts of control systems, Part 1: General principles for design”
This standard may be applied to SRP/CS (safety-related parts of control systems) and all types of machinery, regardless of the type of technology and energy used (electrical, hydraulic, pneumatic, mechanical, etc.). BS EN ISO 13849-1 also lists special requirements for SRP/CS with programmable
BS EN ISO 13849-1 is based on the familiar categories from BS EN 954-1. It examines complete safety functions, including all the components involved in their design. BS EN ISO 13849-1 goes beyond the qualitative approach of EN 954-1 to include a quantitative assessment of the safety functions. A performance level (PL) is used for this, building upon the categories.
Components/devices require the following safety parameters:
The standard describes how to calculate the performance level (PL) for safety-related parts of control systems, based on designated architectures. BS EN ISO 13849-1 refers any deviations to IEC 61508. Where several safety- related parts are combined into one overall system, the standard describes how to calculate the PL that can be achieved.
For additional guidelines on validation EN ISO 13849-1 refers to Part 2, which was published at the end of 2003. This part provides information on fault considerations, maintenance, technical documentation and usage guidelines.
BS EN 62061: “Functional safety of safety-related electrical, electronic and programmable electronic control systems”.
This standard defines requirements and gives recommendations for the design, integration and validation of safety-related electrical, electronic and programmable electronic control systems (SRECS) for machinery. It does not define requirements for the performance of non-electrical (e.g. hydraulic, pneumatic, electromechanical) safety-related control elements for machinery.
BS EN 62061 represents a sector-specific standard under IEC 61508. It describes the implementation of safety-related electrical and electronic control
The safety functions identified from the risk analysis are divided into safety subfunctions; these safety subfunctions are then assigned to actual devices, called subsystems and subsystem elements. Both hardware and software are handled this way.
A safety-related control system is made up of several subsystems. The safety-related characteristics of these subsystems are described through parameters (SIL claim limit and PFHD).
These subsystems may in turn be made up of various interconnected subsystem elements (devices) with parameters to calculate the subsystem’s corresponding PFHD value.
Safety-related parameters for subsystem elements (devices):
Internal parameters to be established during design / construction for a subsystem comprised of subsystem elements:
Detailed explanation of these terms and their use are found in our downloadable Safe Machinery Guide.
A As before, for risk assessment and risk reduction use the standards BS EN 14121-1 and EN 12100. For the safety related electrical control circuits use either BS EN ISO 13849-1 or BS EN 62061. The big question is which of these two standards to use. The logical step from BS EN 954-1 is to use BS EN ISO 13849-1, however, with complex bespoke products and software, BS EN 62061 should be applied.
A. End of 2011
A. Machine builders, buyers, owners and users all have a responsibility for safety.
Users' responsibilities - buying machines and owning existing machines
Users of machines need to ensure that newly-purchased machines are CE marked, and accompanied by a Declaration of Conformity to the Machinery Directive. Machines must be used in accordance with the manufacturer's instructions.
Existing machines taken into service before the Machinery Directive came into force do not need to comply, although they need to comply with PUWER and be safe and fit for purpose.
Modification of machines can be considered as manufacture of a new machine, even if for use in-house, and the company modifying a machine needs to be aware that it might need to issue a Declaration of Conformity and CE marking.
This is implemented in UK law as the Provision and use of Work Equipment Regulations 1998, (PUWER 1998). It applies to the provision of all work equipment, including mobile and lifting equipment, in all workplaces and work situations where the Health and Safety at Work etc Act 1974 (HSW Act) applies. It extends outside Great Britain to some offshore activities. The regulations apply to all employers, the self-employed, and others who have control of the provision of work equipment. They require that all equipment is suitable for use and is inspected and maintained as necessary to ensure that it remains so.
Manufacturers placing machines on the market within the European Economic Area must comply with the requirements of the Machinery Directive. Note that "placing on the market" includes an organisation supplying a machine to itself, i.e. building or modifying machines for its own use, or importing machines into the EEA.
In the UK the Machinery Directive 98/37/EC is implemented as the Supply of Machinery (safety) regulations 1992 as amended.
From 29 December 2009 the relevant UK regulations will be the Supply of Machinery (safety) regulations 2008, which implement the European Machinery Directive 2006/42/EC.
Machines have to comply with the Essential Health and Safety Requirements (EHSRs) listed in Annex I of the Directive, thus setting a common minimum level of protection across the EEA (European Economic Area). Machine manufacturers, or their authorised representatives within the EU, must ensure that the machine is compliant, the Technical File can be made available to the enforcing authorities on request, the CE marking is affixed, and a Declaration of Conformity has been signed, before the machine may be placed on the market within the EU.
A. Peter Still of Schneider Electric has represented GAMBICA and in turn the UK on the IEC committee TC44 for machinery safety throughout the development of the new standard. This has given us a unique insight into the background, requirements, and implications of the new standards. Our Safe Machinery Guide can be downloaded and gives a good overview of the Machinery Directive and contains some worked examples of both BS EN ISO 13849-1 and BS EN 62061.
We can supply the reliability data for all products used in safety applications Reliability Data in Support