ARC 332 Environmental Controls Exam 2: Lighting, Daylight & Acoustics

What is a luminaire?

A complete lighting unit that includes the light source, optical and electrical components, and housing.

How do you determine the diameter of a lamp from its designation?

Divide the number by 8; for example, T8 has a nominal diameter of 1 inch (8/8).

What is the operating principle of incandescent lamps?

Electric current heats a tungsten filament until it glows.

How does a fluorescent lamp generate visible light?

An electrical discharge generates UV light, which a phosphor converts to visible light.

What is the function of a ballast in a fluorescent lamp?

It starts the lamp and limits current.

What is the operating principle of LED lighting?

Current through a semiconductor emits light.

How is luminous efficacy calculated?

Luminous efficacy = luminous flux (lumens) ÷ power input (watts), expressed in lm/W.

What does LPD stand for and how is it calculated?

Lighting Power Density; calculated as total installed lighting watts divided by floor area (W/ft²).

What is the purpose of energy-conscious design in lighting?

To use available daylight, efficient luminaires, light-colored surfaces, and task lighting to minimize energy use.

What is the Lumen Method used for?

To calculate the required number of luminaires based on the lumen output needed for a space.

What is the Coefficient of Utilization (CU)?

The fraction of emitted lumens that reach the workplane.

What does the Light Loss Factor (LLF) account for?

It accounts for reduced light output over time due to factors like lamp aging and dirt.

What is manual control in lighting?

A person adjusts the lighting using a switch, dimmer, or control panel.

What is occupancy control in lighting?

The lighting responds to whether the space is occupied.

What does daylight control do?

It adjusts the lighting in response to available daylight.

What is a Reflected Ceiling Plan (RCP)?

A drawing that shows the ceiling as if it were reflected onto a mirror placed on the floor.

What are common forms of unwanted light in outdoor lighting?

Uplight, light trespass, and glare.

What is the definition of window view quality?

It depends on what can be seen, how much of it is visible, and how clearly it can be seen.

What does CRI stand for and what does it describe?

Color Rendering Index; it describes how accurately colors are rendered under a light source.

What is sound power?

Total acoustic energy emitted per second, measured in watts (W).

What is sound intensity?

Power flow per unit area, measured in watts per square meter (W/m²).

How is sound pressure defined?

Air pressure fluctuation, measured in pascals (Pa).

What is the formula for calculating decibels for intensity?

L = 10 log₁₀(I/I₀), where I₀ = 10⁻¹² W/m².

What does RT60 represent in acoustics?

The time for a sound level to drop by 60 dB after the source stops.

What is the Sabine calculation for reverberation time?

RT60 = 0.05 V / A, where V is room volume and A is equivalent absorption.