Lighting ›
Is the current EN 12464-1 a generally recognized rule of technology?
Exactly five years ago, in August 2011, a new version of EN 2464-1 for lighting in work places was released. This new version added new criteria and procedures to the previous version. The question is, however, whether these innovations have proved their worth. After our experience with this standard how do we assess it today?
Anything new awakens our curiosity and we like trying out something new. But does it offer any additional benefits? Are we able to reach our aim in a better, simpler and faster way? We learn from trying things out and then we tell others about this. A process thus develops which shows us whether what is new is of any real use and whether it provides benefits.
Designers were able to gather this experience with the previous version. For example, the minimum values for median illuminance for working areas of 500lx and for the surrounding area of 300 lx became well known and proved their worth in practice.
So what about the innovations in EN12464-1:2011-08? To what extent have they been adopted in practice? How wide is their application and how well-known are they? Has the standard set of rules become a »generally recognized rule of technology«? And does it form a firm basis which can legally be relied upon?
To start with we will take a look at the main innovations in EN12464-1:2011-08 and the objectives.
Illuminance on surfaces
This criterion is concerned with the main surfaces of the room such as walls and ceiling. Evidence is required for the maintenance value of the median illuminance and its uniformity. If we look at the norm more closely, we see that its aim is to achieve well-balanced distribution of luminous intensity in the field of vision and the creation of brightness in the room.
Illuminance on surfaces, Graphics: DIAL
The background
The background complements the areas which up to now were looked at more closely in relation to the work place. The visual task area and the direct surrounding area are enclosed by a background area with a minimum width of 3 meters. The median illuminance with a defined uniformity must be checked for all three surfaces. The aim of paying attention to this additional area is to ensure sufficient illumination of workplaces in indoor spaces, especially when there is lack of daylight.
Location of the background area, Graphics: DIAL
Median cylindrical illuminance
The median cylindrical illuminance in the area of activity is introduced as an additional parameter for lighting conditions in a room. The aim is to make it easier to clearly identify objects and humans in the room and thus to support communication. In addition to the now well-known task level, a new horizontal level is taken into consideration. Here a distinction is made between an activity, when seated, at a height of 1.2 m and an activity, when standing, at 1.6 m. Yardsticks to be used here are the general minimum values for the maintenance of cylindrical illuminance and of uniformity. Areas such as offices, meeting rooms and classrooms must be taken into special separate account.
Median cylindrical illuminance, Graphics: DIAL
Are these innovations being used?
With these innovations further photometric requirements relating to quantity and quality of lighting are described. However, concrete solutions have not been agreed upon. The aim of such a set of rules is to offer support to lighting planners when creating lighting concepts to ensure good visual conditions and a high degree of visual comfort at the workplace.
This is, therefore, a good basis for arousing interest right at the beginning. We can design light according to this standard but still have freedom to find solutions ourselves. We can gather experience, exchange ideas with colleagues and, finally, judge whether there is any real benefit.
However, in our experience, it is at precisely this point that things come to a standstill. We do not get that far. Nothing is tried out. There is hardly any exchange of information about experience in actual application.
In our daily work with lighting designers and luminaire manufacturers, with participants in seminars and through our own work as independent lighting designers it becomes clear that the new standard has not managed to establish itself. Many lighting designers have never had to provide evidence of or check values for room surfaces of cylindrical illuminance. It is not easy to define exact reasons for doing this. Various conversations and our own experience do, however, confirm that it is also possible to have a good lighting concept without these innovations.
Our impression is that many designers only apply parts of the norm. What is applied is mainly what has already been well-established since the previous 2003 version.
Is the norm a generally recognized rule of technology?
It is doubtful whether the current norm can be defined as a »generally recognized rule of technology«. But what exactly do we mean by this term? There is no definition of this term explicitly in any jurisdiction, but we can nevertheless find it in some rules such as building regulations or in VOB part1 (Construction Tendering and Contract Regulations)
»Recognized rules of technology are those principles and solutions which have proven themselves in practice and have established themselves in most daily work.«
Source: Practical tips »Standards of Technology«, Chamber of Architects NRW
This means that it is not sufficient to prove the principles through scientific findings. Of greater importance is that through practical experience it is possible to reinforce the reputation of the standard and highlight its benefit in practice. In German jurisdiction there is, in principle, the assumption that a standard reflects the recognized rules of technology, so that it quickly acquires a legal meaning. The statement that a set of standards does not meet the generally recognized rules of technology has to be proved.
Evidence has therefore to be provided that the standard does not fulfil at least three of the following attributes:
1. is based on scientific findings
2. information on practical experience is available
3. is common knowledge
4. has proved itself in practice
Differences in the definitions »Commonly recognized rule of technology«, »Present state of technology«, »Present state of knowledge«. Source: Manfred Puche
In the case of EN 12464-1:2011-08 we can see no evidence at all that all four attributes are fulfilled completely.
What does this mean for EN12464-1:2011-08?
Can it be furnished with any legal significance for evaluating the quality of lighting design? Its content could play a big role when it comes to remedying deficiencies in planning and design. The previous 2003 version was well on the way to becoming a recognized rule of technology. But the situation today is problematic. As we see it, the new version of the standard does not seem to be regarded, on its fifth anniversary, as a recognized rule of technology.
Note:
The main emphasis of this article is on the legal situation in Germany.
