KANBrief 1/10

Machine safety standards: unfinished business following adaptation to the new directive

The safety of machinery is a major occupational safety and health function. The subject is also dealt with comprehensively in standards. The task recently arose of adapting the body of standards to the new Machinery Directive. KANBrief discussed current developments with Christoph Preusse, the Chairman of technical committees CEN/TC 114 and ISO/TC 199, “Safety of machinery”.

Mr Preusse, in your view, how is adaptation of the machine safety standards to the new Machinery Directive progressing, and what are the tasks now facing the standards committees?

Thanks to the efforts of those involved, the substantial work of adapting approximately 750 safety standards has progressed swiftly and effectively. Adaptation has for the most part been formal; substantial changes in content were not planned. Nevertheless, it has been found that many standards now also require amendments to their content in order to bring them into line with the new Machinery Directive.

It is important that a body of standards suitable for application in practice be maintained and continually improved. An evaluation phase is necessary in which observations can be made during application of the standards. Key questions in this context include: “How do designers cope with the interrelationships between the various standards?”, and “How much effort must a machinery manufacturer invest in the study of safety standards in order to remain informed?”.

This concept is already being applied in the ISO 12100 safety standard, which is currently available in draft form. The purely editorial merging of the three former basic safety standards (ISO 12100 Parts 1 and 2, “Basic concepts, general principles for design” and ISO 14121, “Risk assessment”) into a single document will be followed by an evaluation phase before further technical amendments are discussed.

How do you expect to benefit from closer cooperation in the future with the CEN and ISO ergonomics committees?

The subjects of safety of machinery and ergonomics are closely related. However, the amendments to the Machinery Directive have revealed a major need for information regarding this relationship. In the past, the two topics have been considered separately. As a result of the work currently in progress at European and international level, and thanks to the initiative of the European Trade Union Institute (ETUI) and KAN, the two areas are gradually moving closer together. Further joint effort by the standards committees is however necessary for this purpose.

A basis for this has now been created in the form of liaison between the ergonomics and machinery committees, i.e. between CEN/ TC 122 and CEN/TC 114 and between ISO/TC 159 and ISO/TC 199. A “bridging paper” is being drawn up to assist the machine designer in implementing the ergonomic requirements. This paper is to raise their acceptance. Ergonomic design, which can be implemented costeffectively at the design phase, is what makes a machine operable in the first instance, thereby creating a basis for safe working practices. It can also prevent manipulation from the outset.

The presumption of conformity to which EN 954-1 (“Safety of machinery – Safety-related parts of control systems – Part 1: General principles for design) gives rise has been extended. What is your opinion on this?

This decision was based upon understandable political but very short-sited economic considerations. In my view, it will weaken both European standardization, and the European machine construction sector.

Extending EN 954-1’s presumption of conformity was superfluous: the standard’s replacement, EN ISO 13849-1, already contains its predecessor and describes procedures for producing solutions where problems arise. Deficiencies in the state of the art of EN 954-1 are also evident with regard to the electrical sister standard, EN IEC 62061. The reasoning behind the extension of EN 954-1’s presumption of conformity was to provide time for enterprises which had been late in adapting to the successor standard, EN ISO 13849-1, which describes the state of the art. It is already evident however that this decision is irrelevant in international machine construction: an enterprise wishing to sell machines employing control technology outside Europe will be measured against the international successor standard.

Machine construction companies should take the opportunity to apply the successor standard as soon as possible, even before the two-year extension has expired. Such a decision would be in the interests both of the companies and of safety.