Artificial Lighting Design - ARCH 342

This set of vocabulary flashcards covers essential terms and calculation methods for artificial lighting design in architecture.

Layered Approach to Lighting Design

A process that begins by thinking in terms of lighting functions or applications categorized into layers.

Control Zone Approach to Lighting Design

A design plan that organizes lighting in terms of zones to ensure effective controlling of the lights.

Directionality of Light

A quality of light that enhances and emphasizes an object's perceived shape or form through various techniques.

Key and Fill light

A lighting technique commonly used in TV studios to provide primary illumination and soften shadows.

Grazing

A lighting technique used to highlight the texture of a surface, often resulting in visual patterns called scallops.

Wall Washing

A technique used to provide uniform illumination across the surface of a wall.

Silhouette

A lighting effect created by illuminating the background to make the subject appear as a dark shape.

Uplight

A directionality technique where light is directed upwards to emphasize higher architectural elements or ceilings.

Color Rendering Index (CRI)

One of the two most common metrics used to define the color quality of a light source.

Correlated Color Temperature (CCT)

A common metric used alongside CRI to define the color appearance and quality of light.

Illuminance

The total luminous flux falling on a work plane per unit area, measured in $Lumen/m^2$ or $Lux$.

Work Plane

The surface where the most important tasks in a room or space are performed.

Lumen (Zonal Cavity) Method

A method for interior lighting design used for general or uniform lighting for rectangular rooms, assuming the room is divided into three zonal cavities.

Coefficient of Utilization (CU)

The percentage of the luminous flux of the lamp(s) or luminaires that reaches the defined working plane in the room.

Room Index (RI)

The geometrical ratio of a room expressed by the formula $RI = \frac{L \times W}{H_m(L + W)}$.

Maintenance Factor (MF)

A factor used in lighting calculations to account for the reduction in light output over time due to aging, dust accumulation, and lamp failure; also known as Light Loss Factor.

Uniformity of Illumination

The ratio of minimum illuminance to average illuminance over an area ($\frac{E_{min}}{E_{ave}}$).

Spacing to Mounting-Height Ratio (SHR)

The ratio derived from the formula $SHR = \frac{S}{H_m}$ where $S$ is luminaire spacing and $H_m$ is mounting height.

Point-by-Point Method

A calculation method used to determine illuminance at specific spots, such as single displays or building façades, when distribution is not uniform.

Candlepower Distribution Curve

Photometric data representing a section cut through a fixture showing the intensity of light emitted in each direction.

Inverse Square Law

A fundamental physical law used in the point-by-point method to calculate the effect of distance on light intensity.

Cosine Law

A law applied in point-by-point calculations that accounts for the orientation of the surface relative to the light source.

Light Power Density (LPD) Method

A calculation method used to estimate preliminary lighting loads based on the power used per unit area, typically measured in $W/m^2$.

Space-by-Space Method

A variation of the LPD method where a building is divided into functional areas like offices or corridors to calculate preliminary lighting loads.

Whole Building Method

An LPD estimation method used for an entire building or single, independent occupancies within a multi-occupancy building.

Dialux

A specific computer software mentioned as a tool for calculating illumination levels.