7S3X0 – Introduction to Building Physics and Material science
Light reader
Chapter 1: Building and light
1.1 THE BUILT ENVIRONMENT AND LIGHT
Light can be described in three quality-related terms:
- Form: light provides information about shape, colour, and texture
These objects can only be perceived when rays of light are being reflected by objects. This reflected
light activates the photosensitive sensors in our eyes. Light provides us with information about the
shape of objects, the colour, and the texture.
The lighting largely determines the impression of space by the material characteristics of the interior
surfaces. The light may intensify or diminish the visual characteristics of the specific materials,
textures, and shapes of a building.
- Feeling
The amount of light, distribution and colour results in an association towards the user. If a room is lit
with a more bluish light we associate this with a cool, distant and clinical space. We expect that the
lighting of a room is aligned with the function.
- Function: a functional aspect of light to enable people to perform their visual task
The functional aspects of light enable people to perform their visual tasks. Whether the lighting
complies with the requirements depends on the amount of light, but also on the distribution of it
across the room, the composition of light and whether or not glare is present.
The building envelope influences both the daylight quantity and quality of a space and the outdoor
view.
1.2 WHAT IS LIGHT?
There are two answers to this question:
1. The first being that it is a wave phenomenon
2. A continuing stream of photons.
For the science of lighting, it is customary to conceive light as an electromagnetic wave phenomenon.
Only a small portion of the light is visible for us, this is the portion with wavelengths between 380 nm
to 780 nm. The other kinds of light are:
- Ultraviolet radiation (UV) with wavelengths between 250 nm and 380
- Infrared radiation with wavelengths between 780 nm and 1mm
All matter with a temperature above 1K emits electromagnetic radiation. We call this emittance, this
can be distinguished in light emittance (wavelengths visible to us) and radiant emittance (all
wavelengths) As the temperature rises you feel more heat caused by radiation. Two remarks to this
are:
1. The wavelength range, in which a relatively large amount of radiation is emitted, shifts to
shorter wavelengths. This phenomenon is described in Wien’s law of displacement:
𝜆𝜆𝑚𝑚𝑚𝑚𝑚𝑚 ∗ 𝑇𝑇 = 𝑏𝑏
Lenore van Vliet - 1377892
Light reader
Chapter 1: Building and light
1.1 THE BUILT ENVIRONMENT AND LIGHT
Light can be described in three quality-related terms:
- Form: light provides information about shape, colour, and texture
These objects can only be perceived when rays of light are being reflected by objects. This reflected
light activates the photosensitive sensors in our eyes. Light provides us with information about the
shape of objects, the colour, and the texture.
The lighting largely determines the impression of space by the material characteristics of the interior
surfaces. The light may intensify or diminish the visual characteristics of the specific materials,
textures, and shapes of a building.
- Feeling
The amount of light, distribution and colour results in an association towards the user. If a room is lit
with a more bluish light we associate this with a cool, distant and clinical space. We expect that the
lighting of a room is aligned with the function.
- Function: a functional aspect of light to enable people to perform their visual task
The functional aspects of light enable people to perform their visual tasks. Whether the lighting
complies with the requirements depends on the amount of light, but also on the distribution of it
across the room, the composition of light and whether or not glare is present.
The building envelope influences both the daylight quantity and quality of a space and the outdoor
view.
1.2 WHAT IS LIGHT?
There are two answers to this question:
1. The first being that it is a wave phenomenon
2. A continuing stream of photons.
For the science of lighting, it is customary to conceive light as an electromagnetic wave phenomenon.
Only a small portion of the light is visible for us, this is the portion with wavelengths between 380 nm
to 780 nm. The other kinds of light are:
- Ultraviolet radiation (UV) with wavelengths between 250 nm and 380
- Infrared radiation with wavelengths between 780 nm and 1mm
All matter with a temperature above 1K emits electromagnetic radiation. We call this emittance, this
can be distinguished in light emittance (wavelengths visible to us) and radiant emittance (all
wavelengths) As the temperature rises you feel more heat caused by radiation. Two remarks to this
are:
1. The wavelength range, in which a relatively large amount of radiation is emitted, shifts to
shorter wavelengths. This phenomenon is described in Wien’s law of displacement:
𝜆𝜆𝑚𝑚𝑚𝑚𝑚𝑚 ∗ 𝑇𝑇 = 𝑏𝑏
Lenore van Vliet - 1377892
