Complete overhaul for lighting terminology

In the world of standards development, terminology is where it all begins.

A big endeavour: revising lighting terminology for standards.

Terminology provides a set of agreed definitions and terms for concepts in specific fields, reducing the level of ambiguity associated with words and sentences. Before starting work on technical aspects, IEC experts first must agree on the terminology used in the standards, so that everyone understands the concepts which are referred to.

The IEC Electropedia, also known as the International Electrotechnical Vocabulary (IEV), is maintained and updated by the earliest IEC Technical Committee, IEC TC 1. The content of the Electropedia is also published in the IEC 60050 series of standards, which can be ordered from the IEC webstore.

Keeping abreast with the latest technology developments, and how these have an impact on terminology, is a must for IEC experts: terminology evolves together with the changing technological landscape, at a pace that no one would have even imagined 10 years ago. A case in point is the terminology for lighting. It has changed significantly over the decade, with the widespread adoption of Light Emitting Diodes (LED), among other developments (read about these in Smart Lighting). With a view to bringing the terminology for lighting up to date, the IEC published a 190-page document just before the end of 2020. This turned out to be massive endeavour, which involved close cooperation between the IEC and the International Commission for Illumination (CIE).

IEC 60050-845 was prepared jointly by IEC TC 34: Lighting, and the CIE under the responsibility of IEC TC 1. It is completely harmonized with the second edition of the CIE standard CIE S 017:2020 ILV: International Lighting Vocabulary.

CIE Technical Manager Peter Zwick was one of the main architects of this formidable task, together with Wei Zhang from IEC TC 34 and Joanna Goodwin, Terminology Coordinator at the IEC. “It was a long journey but slowly and surely we tamed what we used to call “the monster”,” Zwick says.

The challenge of LED

Among the difficulties met along the way was getting all the different participants to agree on LED terminology. “One of our main challenges was to harmonize the terms and definitions for LED. It concerned not only the term LED itself but also other terms such as LED module, LED pack and so on. There were quite a few discrepancies between IEC practice and what the CIE had defined in a supplement to its International Lighting Vocabulary, which was published in 2015. We had several meetings to iron out the differences between us,” Zwick describes.

Zhang concurs: “one of the issues we had with LED is that it refers not only to the physical unit but also to the technology and that resulted in many discussions. We also needed to consider consistency aspects for many other terms based on LED, not only the accuracy of the term LED itself.”

The work carried out was much more than a simple revision. “The initial edition of the standard was published in 1987 and this second edition required a total redraft of most of the standard, introducing a complete new section on Imaging. We included new terms and even when we referred to old terms and definitions, sometimes we needed to consider technical changes in these,” Zhang explains.

Marketing versus technology

One of the other challenges was to avoid the allure of terminology widely used in the public domain but which has more of a marketing connotation than a technology usefulness.

As Zwick mentions: “Like smart lighting, we found that human centric lighting is more of a marketing term than an engineering one. We decided to follow the CIE and ISO/TC 274 and introduce the term integrative lighting instead. This shows to what extent the terminology used for standards is not the same as terms commonly referred to by consumers, for instance. We need to speak a common language understood by those who use the standards, notably the various industry participants.”

Human centric lighting, or integrative lighting, is considered by some experts to be one of the next disruptive lighting technologies. Using LED, it enables scientist to better match lighting with the human being’s sleeping patterns and working cycles. Finely tuned levels of LED lighting can help human beings be more productive at work and suffer less from sleep disruption or headaches, etc…

The good working relationship built between the three main participants helped to move things along. “It is in some ways the work of a lifetime and we shared a great rapport between us and became friends, which helped immensely,” Zwick says. Zhang agrees: “It was a very tough process but we built great memories working together.”