Heat without fire for manufacturing

Heady times for TC 27 experts

By Morand Fachot

Electroheating, the high-power heating of various materials using electrical energy, is used to make countless products we use, consume or even eat. Steel or aluminium ingots, ceramics and ready-made meals may be produced using this process. IEC TC (Technical Committee) 27: Industrial electroheating and electromagnetic processing, prepares International Standards for the many installations used in the sector.

Convection IR / convection oven for automotive dashboards" (Photo: Infrared Heating Technologies) Convection IR / convection oven for automotive dashboards" (Photo: Infrared Heating Technologies)

Standardization is newer than technology

Electroheating was first introduced to the steel industry in the form of electric arc furnaces in the early 20th century. An electric arc is a plasma discharge that forms when a high electric current passes between two electrically conducting materials or "electrodes" through a normally nonconductive medium such as air. In industry, this process is used for smelting and refining, welding metals, plasma cutting and many other applications.

A number of other electroheating technologies, such as infrared radiation, induction, radio frequency and microwave, have emerged since electric arc furnaces were first installed. Electroheating is applied in generic industrial operations such as fluid heating, calcination, drying, evaporation, sterilization, heat treatment, metal and non-metal heating, melting, smelting/agglomeration, curing and forming.

Multiple applications

Such technologies are used for producing or processing many different materials, which range from metals to glass and from natural fibres to polymers. They are also used to prepare paper and foodstuffs.

IEC TC 27 was established in 1937 "to prepare international standards for characteristics, safety requirements and test methods for industrial electroheating installations". Its standardization work actually began in the 1960s. Its first standards, including IEC 60239, which dealt with dimensions of graphite electrodes for arc furnaces, were published in 1967.

The scope of TC 27 covers all aspects of industrial electroheating, including electroheat-based surface treatment technologies, and combinations of technologies.

Broad customer base, far-reaching remit

Electroheating equipment encompasses a wide variety of heating methods. Users of TC 27 standards are to be found in a range of heavy to light industrial sectors, reflecting the wide variety of electroheating applications. They include the iron, steel and non-ferrous metal industries; the automotive and machinery industries and the cement, glass, ceramics and chemical industries, as well as the food industry.

Emerging sectors such as nanotechnology, biotechnology, optoelectronics, the PV (photovoltaic) industry and the re-processing of waste and dangerous products require precise or unique heating methods. They also open up new perspectives for electroheating processes and present the need for new or updated standards. New heating processes that use, for instance, laser or microwave heating, may sometimes provide the only possible solution to meet the requirements of a number of disparate industries.

Nevertheless, standardization in industrial electroheating is of great importance for manufacturers of equipment and installations. These are mainly small and medium-sized enterprises and their products are often individually-designed and custom-engineered according to the specific needs of end-users. Establishing common International Standards for equipment with different characteristics and safety requirements may be difficult, but fully supports the trends towards global harmonization and the reduction of trade barriers.

Specific issues

Electroheating installations that use electromagnetic processing may prove to be sources of EMI (electromagnetic interference), leading the TC to address specific aspects of EMC (electromagnetic compatibility) and EMF (electromagnetic fields).

As electroheating technologies extend to more sectors and represent an increasingly large percentage of industrial electricity consumption, EEE (electrical energy efficiency) becomes a pressing issue.

To tackle the energy efficiency issue, TC 27 set up WG (Working Group) 29: Energy efficiency in electroheating installations, to "develop guidelines for determination of criteria (…) for allowing fair comparisons and evaluations of the performance and efficiency within particular sub-categories of electroheating equipment / installations".

TC 27 also established WG 30: Industrial infrared electroheating installations, "to develop standards concerning safety and test methods for industrial infrared electroheating installations".

Multiple objectives

Noting an "increasing demand for energy savings, product quality and environmental protection" and that "application areas of electroheating methods are not only expanding but also becoming a must for many industrial sectors", TC 27 lists as its objectives and priorities for the next 3-5 years:

  • revision of the 12 publications in the IEC 60519 series of standard that deal with the safety of industrial electroheating installations
  • preparation of additional parts covering particular industrial electroheating installations, such as those with infrared emitters or laser heating equipment
  • revision of the large series of test standards, which should be updated in view of technological developments and market needs.

In addition to its revision work, TC 27 also intends to start work on new standards, while amending the existing publications, to address:

  • EEE issues (guidelines for the classification of equipment/installation to determine the performance/efficiency of a given system and a comparison with other systems of that class)
  • EMC and EMF issues
  • safety and test methods for different electroheating installations, in particular new ones or those not covered by existing standards
  • safety and reliability aspects of combining heavy current electroheating equipment with sophisticated digital control methods

To take into account the predicted long-term evolution of electroheating technologies, TC 27 announces its intention to undertake new projects aimed at developing safety and test standards for infrared heating technologies, plasma arc furnace installations, new casting systems and electromagnetic processing of materials.

The development of current electroheating processes, coupled with the emergence of new technologies and considered in conjunction with IEC TC 27's objectives, point to the likelihood of an extremely busy agenda for this TC in coming years.

Convection IR / convection oven for automotive dashboards" (Photo: Infrared Heating Technologies) Convection IR / convection oven for automotive dashboards" (Photo: Infrared Heating Technologies)
Vacuum drying oven used in pharmaceutical and chemical industries (Photo: IBK GmbH) Vacuum drying oven used in pharmaceutical and chemical industries (Photo: IBK GmbH)
tc-6_convection_furnace_lrg Aluminium alloy convection conveyor furnace (Photo: Infrared Heating Technologies)