BST211 Environmental Technology II - Lighting Intro

Objective of Lighting: Privacy

• Privacy is associated with low illuminance, non-uniform lighting, and darker zones around the occupant, reinforcing the impression of privacy

Objective of Lighting: Illumination Purposes

• Lighting design creates luminance (brightness) in specific areas to support activities.

Objective of Lighting: Health

• Natural lighting can promote health when combined with proper ventilation, like during sunrise

Nature of Light

• Light is crucial to human perception of the environment
• Artificial and natural light sources are used in buildings and controlled in many ways
• Light is electromagnetic radiation in the form of waves

What is Light?

• Light is energy
• It is a wave phenomenon
• It is radiated from processes in atomic structures of different materials, causing a wide range of effects

Light as an Electromagnetic Wave

• Visible light occupies a narrow band of the full electromagnetic spectrum
• Visible light is a small part of the electromagnetic spectrum, along with ultraviolet (UV) and infrared (IR) regions
• UV, Visible, Infrared wavelengths are important to designers
• Details about wavelengths for each type of light are included in various tables

Electromagnetic Spectrum (Figure 1)

• The full electromagnetic spectrum is displayed and includes different types of radiation: Radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma rays.
• Each type of radiation has specific wavelength scales and frequencies (in Hz)
• The temperature of objects relates to the emitted radiation wavelength

Visible Light Region

• Shows the visible light spectrum and the parts of the electromagnetic spectrum related to visible light (infrared, ultraviolet, etc)

Light as Electromagnetic Radiation

• Light sources do not typically contain all wavelengths equally, yet they appear as "white"
• Shorter wavelengths have higher frequencies and thus more energy; longer wavelengths have lower frequencies and thus less energy.
• Light has specific characteristics at various wavelengths

Uses of Specific UV Wavelength Bands

• Provides a list of wavelength bands of UV light and their applications (e.g., lithography, drug detection, medical imaging)

Hazards of UV Radiation

• Adverse health effects associated with UV radiation wavelengths below 315 nm (actinic ultraviolet) are documented
• The table provides information on different UV bands, their associated wavelengths, primary visual hazards, and other hazards

Properties of Electromagnetic Waves

• Electromagnetic energy travels via fluctuations of electric and magnetic fields
• Does not require a medium to travel
• Electromagnetic radiation has varying wavelengths and frequencies
• Speed of light is approximately 3 x 108 m/s in a vacuum

Visible Radiation

• White light is the combination of all visible wavelengths
• Wavelengths of visible light range from approximately 380 to 770 nm (nanometers)
• The visible spectrum includes colors like red, orange, yellow, green, blue, indigo, and violet.

Non-Visible Radiation

• UV light is not visible but can damage tissue and other organic materials.
• Ultraviolet radiation maintains the body, although excessive amounts can be harmful to the eyes and skin.
• Applications include killing bacteria and medical use.
• Infrared radiation, commonly felt as heat, is a type of electromagnetic radiation