Environmentals exam 2

luminaire

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

lamp designation

the letter indicates the lamp shape, and the number indicates the nominal diameter in eighths of an inch. For example, T8 has a nominal diameter of 8/8 = 1 inch.

Incandescent Lamp Source

Electric current heats a tungsten filament until it glows.

Fluorescent Lamp Source

Electrical discharge generates UV; a phosphor converts UV to visible light. A ballast starts the lamp and limits current.

LED Lamp Source

Current through a semiconductor emits light. Efficient blue LEDs with phosphors enabled practical white LED lighting.

Luminous efficacy

luminous flux (lumens) ÷ power input (watts)

Lighting power density

LPD = total installed lighting watts / floor area (W/ft²)

Solve for LPD given 8 fixtures and 60 W

8 fixtures × 60 W = 480 W; 480 W ÷ 800 ft² = 0.60 W/ft².

Illuminance Point method

E=Luminous Intensity/Distance² . If the angle is landing on a horizontal surface multiply by cos. if angle is landing on a vertical surface multiply by sin.

Number of luminaires using lumen method

Solve for N!! If the result is not a whole number, round up to the next whole luminaire!!

Manual control

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

Occupancy control

The lighting responds to whether the space is occupied

Daylight control

The lighting adjusts in response to available daylight

Time control

The lighting changes according to a programmed schedule

Scene/preset control

A selected preset changes multiple lighting settings at once

Reflected Ceiling Plan (RCP)

shows the ceiling as if it were reflected onto a mirror placed on the floor

Outdoor lighting

should provide appropriate visibility and safety while minimizing unwanted light and environmental impacts. Common forms of unwanted light include uplight directed into the night sky, light trespass extending beyond the intended area, and glare that causes discomfort or reduces visibility.

Proper fixture direction and shielding

help control light pollution.

Higher illuminance

does not necessarily improve visibility and may increase glare.

CRI

describes color rendering and does not by itself indicate the level of light pollution.

Unnecessary nighttime lighting

may disturb nocturnal wildlife

Window-view quality

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

window View content

The features visible through the window, such as the sky, vegetation, buildings, or activity.

window View access

The amount of the outdoor view visible from a particular position.

window View clarity

How clearly the view can be seen through glazing, shades, or other obstructions.

Sound in air

a longitudinal wave of compressions (higher pressure) and rarefactions (lower pressure).

Frequency

cycles per second (Hz)

wavelength

distance between corresponding points of successive waves.

Sound power

Total acoustic energy emitted per second, W.

Sound intensity

Power flow per unit area, W/m².

Sound pressure

Air pressure fluctuation, Pa.

Reflection

returns sound to the room

absorption

takes sound energy into a material

transmission

passes sound through a partition

RT60

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