Avoiding accidents

Adding electrical equipment to industrial machines for safer operation

By Morand Fachot

Equipment such as machine tools and robots has been used extensively in a variety of manufacturing sectors for decades. Individuals working with or in close proximity to these machines are reliant on their safe operation for protection, as are nearby installations. IEC TC (Technical Committee) 44: Safety of machinery – Electrotechnical aspects, prepares International Standards to ensure this is the case.

Work near robots requires special safety measures and equipment (Photo: ABB) Work near robots requires special safety measures and equipment (Photo: ABB)

Protecting users of industrial machines from risk

However industrial machines are powered, in many instances their operation entails risks. Even when used carefully, they may cause injuries or death.

The addition of electrical equipment, such as electromechanical sensors and switches that can activate safeguarding mechanisms to keep operators at a safe distance or halt operation automatically in case of danger, can prevent accidents occurring or reduce their severity.

Among the many IEC TCs that prepare International Standards for these devices, IEC TC 44 is notable as it aims to protect users from the risks posed by all kinds of machines by preparing standards for electrical equipment associated with machinery.

Its work is closely linked to horizontal safety standards in the IEC 61508 series prepared by IEC SC 65A: System aspects [of industrial-process measurement, control and automation] .

Adding electrical equipment to ensure safety

Industrial machines may be powered by kinetic, electrical, hydraulic or pneumatic energy. Whatever the source, there are often similar safety issues. By adding electrical equipment, individuals can be prevented from coming too close to, or interfering with, machinery in operation. The addition also enables machines to be shut down in case of malfunction or failure. The added equipment may help prevent injuries or even death occurring.

International Standards developed by TC 44 include general and specific requirements for different types of electrical equipment used with machines. They may concern indication, marking and actuation – including visual, acoustic and tactile signals – as well as the location and operation of actuators.

TC 44 International Standards also cover ESPE (electro-sensitive protective equipment), such as various kinds of AOPDs (active opto-electronic protective devices) and other equipment designed to detect human presence.

Wide scope, broad international participation and interest

TC 44 was created in 1957 to develop safety-related standards for electrical equipment associated with industrial machines, particularly machine tools and large machinery. It held its first plenary meeting in 1959. Its scope has been reviewed and amended regularly to reflect technological developments and the demands of the industry sectors it serves, ensuring that it continues to meet their needs. Its present activities comprise three main elements:

  • preparation of International Standards relating primarily to non-portable electrotechnical equipment and machinery systems, including machinery assemblies
  • preparation of International Standards for electrotechnical equipment and systems relating to the protection of persons from specific machinery hazards, taking into account a coordinated systems approach
  • co-ordination with ISO (International Organization for Standardization) on all matters concerning the safety of machinery

The TC brings together 130 experts from 34 participating and observer countries, reflecting the significance of its work. As all TC 44 standards are safety-related, they are widely used by regulators for detailing their technical laws and regulations (e.g. European Machinery Directive 2006/42/EC) and in B2B (business to business) contracts. The major customers of TC 44 standards are Technical Committees dealing with machinery safety within ISO and CEN (European Committee for Standardization) .

Technology and market trends

The following technology trends have an impact on the TC's work:

  • safety functions
  • functional safety, including software
  • development and application of smart sensors
  • remote diagnostics of plant and equipment
  • use of communication networks (bus systems) for machinery safety-related control functions
  • cableless control
  • switching devices on semiconductor basis

Market trends also drive safety considerations. Industrial machines are not produced, traded and operated in a single country but globally. International customers expect to be presented with common solutions that can be used in several countries. This allows them to harmonize their sites and plants globally to rationalize their production procedures and to save costs through the globally-organized purchase of production equipment. These TC 44 International Standards are increasingly applicable worldwide.

Structure and standards

For developing International Standards covering a wide range of equipment TC 44 is organized into 4 WGs (Working Groups), one Project Team that looks at requirements for the electrical equipment for machine tools, 7 MTs (Maintenance Teams) for existing standards, and a JWG (Joint Working Group) with ISO TC 199: Safety of machinery.

TC 44 has published 13 International Standards. They include the IEC 60204 series of International Standards covering the electrical equipment of machines, the IEC 61310 series dealing with indication, marking and actuation, and the IEC 61496 series for electro-sensitive protective equipment.

TC 44 has also published two TRs (Technical Reports) and a TS (Technical Specification).

Objectives and prospects

TC 44 aims to keep its International Standards up to date to reflect new/changing technologies and to ensure they are state of the art at the time they are drafted.

It states that it will work with ISO TC 199 to merge IEC 62061 and ISO 13849-1 into a dual logo IEC/ISO standard.

TC 44 wants to raise worldwide awareness of its International Standards by increasing awareness amongst industrial customers who apply TC 44 standards. This may be effected through contact with NCs, workshops, presentations and other distributed material.

As industrialisation extends to more and more countries, and automation is introduced to all sectors, the safety of industrial machines, which are traded on a global scale, becomes ever more important. The work of IEC TC 44 experts, which is constantly being updated and expanded will therefore remain essential to ensure that the safe operation of machinery throughout the world continues to increase.

Work near robots requires special safety measures and equipment (Photo: ABB) Work near robots requires special safety measures and equipment (Photo: ABB)
Emergency stop switch Emergency stop switch
Safety light curtains switch off machinery if workers get too close Safety light curtains switch off machinery if workers get too close