Lighting facades and trees - Light studies - Planning light

Defining room borders with light

At night, light renders facades and buildings visible. In contrast to interiors, illuminated vertical planes outdoors do not communicate a feeling of depth but limit the space. Wallwashing therefore provides orientation and creates visual references – also from the inside to the outside. For planar illumination, recessed floor luminaires or projectors with wallwash or flood lenses are suitable.
Added value of facade lighting:
- good visibility of all room elements
- limits room depth
- natural appearance of facades and buildings

Rule of thumb for arranging planar lighting

Outside, uniform vertical lighting defines spatial borders. The wall distance (a) of wallwashers should be around one third of the wall height (h) for this purpose. For good linear uniformity the luminaire distance (d) of recessed floor luminaires can be up to 1.3 times the distance to the wall (a) (up to 1.2 times with projectors).

a = 1/3 x h
d ≤ 1.2 to 1.3 x a

For projectors this gives an inclination angle (γ) of approx. 55°.

γ = 55°

Tip for luminaire selection: With recessed floor luminaires observe protection rating IP 68 and utilise a resin filled coupling/branching sleeve to enable a watertight cable connection (equivalent to Cellpack Type MR05 (Art. No: 124508) or Type Y00/EG (Art. No: 133841). This prevents humidity being drawn into the cable when the luminaire cools down.

Creating hierarchies with light

Exterior accent lighting enables visual references to be established over long distances. The focused lighting creates hierarchies of perception via balanced contrasts to emphasise buildings and objects both near and far. Darkness can be utilised in this regard because contrasts can be distinctly seen from an illuminance ratio of 1:5.
Added value of accent lighting:
- concise perception hierarchy due to various lighting levels
- eye-catching effects from grazing light

Rule of thumb for arranging accentuating lighting

Facade luminaires structure vertical surfaces with light directed upwards or downwards. Their grazing light also emphasises the plasticity of materials. To avoid glare for pedestrians, luminaires emitting light upwards should not be mounted below eye level (h).

h = eye level

For the all-round lighting of freestanding objects such as trees, a configuration (β) of three luminaires each offset by 120° is suitable.

β = 120°

Tip for luminaire selection:
Good glare control increases the accenting effect. Important: To avoid light pollution, upward light should be directed towards the facade in order to prevent light spill.