When light offers a warm welcome. Attractively designing foyers with qualitative lighting design.

Thinking in quality of light instead of lux values

Technically well-informed designers start a quantitative lighting design for foyers by using the appropriate standards. Designers need to be guided by key figures for illuminance, uniformity and glare evaluation but should also be careful not to ignore the qualitative elements. Because numerical values for safety, orientation and work tasks were decisive during development of these standards, design aspects were hardly integrated. As a consequence, project managers often focus precisely on considering limit values in the design process even though they lack experience as to whether slight deviations might already cause significant difficulties. Qualitative lighting design on the other hand focuses more holistically on perception, taking into account requirements concerning visual tasks as well as psychological needs when aiming for higher levels of well-being.

Kelly's categories are also ideal for clearly explaining the complexity of a lighting solution to constructors and for drawing up concepts for foyers. Lighting designers can of course also dispense with categories if they wish to create a special light effect, for example the avoidance of general lighting when creating especially dramatic presentations with accent light. Kelly developed a masterpiece in qualitative lighting design for the prestigious foyer of the Seagram Building in New York, designed by the architects Mies van der Rohe and Philip Johnson and completed in 1958. The grazing light on the cubes for the elevators not only provides orientation but also communicates a high-quality impression when entering the building thanks to a finely nuanced play of light and shadow on the travertine walls. For passers-by on the plaza outside, the vertical illuminance creates a bright and transparent spatial impression of the fenestrated foyer. The brightly flooded ground floor also gives the skyscraper a pleasantly lightweight appearance. Downlights installed along the façade create the impression of a carpet of light between the interior and exterior and also emphasise the prestigious welcome. The principles of vertical illuminance and light carpets have lost none of their relevance in the present day and age because they reference general psychological needs with regard to perception.

Another design parameter in perception-orientated lighting design is the consistency of room patterns and light patterns. A large white wall represents a uniform, clear shape. However, downlights on the ceiling are often found in front of walls in foyers that create characteristic light cone contours on the wall, thereby negatively impacting the clarity of the wall. As a result the luminance curve creates a new pattern where the upper part of the wall remains dark and the lower part appears bright – separated by a highly conspicuous row of parabolas. In this case the room pattern and light pattern show no consistency because an antithesis is created between the uniform wall material and the bright-dark contrast, thereby hindering the readability of the room. Wallwashing creates a different impression. The uniform distribution of brightness from top to bottom and along the complete wall creates a distinct uniformity of the space and light and supports orientation in the foyer. Entrance halls with wallwashing also radiate a greater degree of calmness because no bright-dark transitions on the walls fight for attention.

If visitors to the foyer then go to an information area or coffee counter, it is also recommended to work with bright vertical surfaces here as well, in order to guide attention to these locations. When using high quality or unusual wall elements in particular, suitable lighting is able to emphasise the inherent quality of their materials, for example by using grazing light on raw natural stone. Vertical illuminance is also ideal for emphasising pictures or building columns as interior elements. A narrow accentuated and optionally oval light cone, planar wallwashing or striking grazing light can be used according to the size, proportion and material.

The product ranges can be efficiently used for various situations thanks to a consistent luminaire design with various light distributions, lumen packages and light colours. With spotlights, lighting designers also benefit from the flexibility of the lens system. Replaceable Spherolit lenses allow simple adjustment of light distribution in the same luminaire housing, for example from spot to flood or even to an asymmetric wallwash. This gives building constructors the chance to flexibly modify the lighting with subsequent redesigns, new artworks or other furniture in the waiting area for example, and to achieve a long service life.

Quantitative and qualitative lighting design of a foyer in comparison

The comparison of a quantitative and qualitative lighting concept for the reception area in the headquarters of a mid-sized company demonstrates the design-, technical- and energetic potential of perception-orientated lighting design. The situation: visitors to the large, two-storey entrance hall find a reception desk and several standing tables with stools. Daylight enters the foyer on one side through the large glass façade, and guests access the seminar rooms on the upper storey via a wide staircase on the opposite side. For quantitative lighting design, the requisite illuminance levels were initially analysed based on the appropriate standards and specific functional requirements. This gave a horizontal illuminance of 100lx with high uniformity for the general circulation areas. Illuminance of at least 300lx was assumed for the workstations at the reception desk. Wide distribution LED downlights arranged in a regular pattern are suitable for efficient lighting with good uniformity. The required 30 recessed ceiling luminaires generate efficiency of 3.64W/m².

Summary: sufficiently welcoming with light

With the change in perspective from a quantitative lighting design aligned to standards to a qualitatively-oriented foyer design, this more attractive lighting solution not only achieves added value for visitors but also cuts investment and operating costs for the building owners. When entering the foyer the lighting of the walls with e.g. wallwashing is an important strategy for a bright spatial impression. The subdivision into zones such as information, circulation area and waiting area in foyers helps to dispense with inefficient generalisations that assume maximum requirements for illuminance and homogeneity, and to develop an efficient as well as attractive solution in each case. To achieve high acceptance levels with visitors it is recommended to pay attention to good visual comfort by using narrow light distributions as well as luminaires with good glare control. Because foyers communicate the first impression of a company or establishment, lighting can be ideally used as a medium not only for visualising functions and offering orientation but also for understanding light as a tool for emphasising the brand appearance.

Lighting recommendations for foyers

- Accentuating important elements such as the reception, stairway and elevators aids orientation.
- Wallwashing creates a brighter and more generous impression of the space.
- Illuminating the wall opposite the entrance creates spatial depth and contributes importantly to the external impression of the foyer.
- A specific lighting concept for waiting areas using accent lighting is able to create a private atmosphere within a large foyer illuminated with general lighting.
- The accent lighting of objects or areas should have a contrast of at least 1:5 to the surroundings to be distinctly perceivable for the eye.
- It is recommended specifically in high foyers to pay attention to good visual comfort, to use narrow instead of wide halfpeak divergence and avoid high cut-off angles, thereby avoiding direct glare caused by the luminaires.
- Energy consumption can be optimised by using light control and daylight sensors and lighting levels can be optimally matched to day and night situations.