Environmental Control Systems II - Lighting Lecture 7

These flashcards cover key terms and concepts related to lighting in environmental control systems.

Light

Defined as that portion of the electromagnetic spectrum to which our eyes are visually sensitive.

Lumen

A unit of measurement quantifying how much visible light a source emits, also known as luminous flux.

Efficacy

The ratio of light output (lumens) to energy input (watts) for a light source.

Candlepower

Describes the intensity of the beam in any direction, measured in candelas.

Illuminance

The number of lumens falling on each square foot (or meter) of a surface, measured in footcandles (lux).

Brightness/Luminance

Brightness refers to the perception of an observer; luminance measures light intensity leaving a surface.

Reflectance Factor (RF)

Indicates how much of the light falling on a surface is reflected; varies by surface color and finish.

Transmittance

Describes the amount of light transmitted compared to incident light; affects visibility of light sources.

Color Temperature

Describes the color of a light source in kelvin (K), indicating warmth or coolness of light.

Color Rendering Index (CRI)

Compares light sources' ability to render colors naturally against a standard source, with values up to 100.

Full-spectrum white light

Light that accurately renders colors, important for precise color representation.

Footcandle

A measure of illuminance representing one lumen per square foot.

Reflective Surfaces

Surfaces can reflect light in both specular and diffuse manners depending on texture and smoothness.

Incandescent, Halogen, CFL, LED

Types of light bulbs compared in terms of annual operation cost, efficacy, and efficiency.