Building Utilities 2 - Architectural Acoustics, Lighting, Electrical, HVAC, Signal Systems & Vertical Transportation

Comprehensive set of 300 VOCABULARY flashcards covering Architectural Acoustics, Lighting, Electrical Systems, HVAC, Signal Systems, and Vertical Transportation.

Photometry

The science that deals with the measurement of light.

Candle Power

The unit of intensity of light of one standard candle whose light is concentrated at a point at the center of a hollow sphere of $1\,foot$ radius.

Standard Candle

The brightness of a black body at the temperature of freezing platinum.

Lumen

The unit of luminous flux representing the amount of light falling on a surface from a light source.

Foot-Candle

The unit of illumination on an area of $1\,sq\,ft$ when $1\,lumen$ of flux is uniformly distributed over it.

Illumination Formula

$E = I / D^2$, where $E$ is illumination in foot-candles, $I$ is candle power, and $D$ is distance in feet.

Light Diffusion

The scattering of light in various directions when light rays strike a rough, opaque surface.

Light Polarization

The elimination of horizontal light rays when striking polarized glass, allowing vertical rays to penetrate and create soft lighting.

Light Transmission

The process where light rays strike a plain transparent surface that allows the rays to proceed farther.

Light Reflection

The bouncing back of light when striking a silvered or smooth surface where the angle of incidence equals the angle of reflection.

Light Refraction

The bending of light rays when passing at an angle from one medium to another of different density.

Candle Power Distribution Curve

A graphic representation of the distribution of light intensity emitted by a luminaire.

Natural Light

Daylight, which is considered the cheapest and most economical kind of architectural lighting.

Incandescent Lighting Effect

Artificial light with a stimulating effect conducive to drinking and inducing sleep, best suited for bars and nightclubs.

Fluorescent Lighting Effect

Artificial light similar to daylight, conducive to eating, reading, and studying.

Luminous Flux

The rate of flow of visible light per unit time, expressed in lumens ($lm$).

Luminous Intensity

The light power emitted by a source in a particular direction, expressed in candelas ($cd$).

Luminous Efficacy

The ratio of light output of a lamp to the electrical power consumed, measured in lumens per watt ($lm/W$).

Color Rendering Index (CRI)

A numerical rating system comparing the color rendering accuracy of a light source to a reference standard lamp.

Correlated Color Temperature (CCT)

The absolute temperature of a blackbody radiator measured in kelvin ($K$) describing the color appearance of light.

Acoustics

The branch of science that deals with the study, control, and propagation of waves conducted through matter.

Architectural Acoustics

The branch of acoustics that studies sound behavior when air is contained within a room or enclosed architectural space.

Church Acoustics

A sub-division of architectural acoustics focusing on worship and cathedral spaces.

Speed of Sound in Air

$1130\,ft/s$ or $344\,m/s$ at sea level ($22\,^\circ C$ / $72\,^\circ F$).

Sound Level

The measure of the strength or intensity of sound, measured in decibels ($dB$) with a meter.

Threshold of Quiet Sound

$0\,dB$, the lowest threshold of human hearing.

Onset of Painful Sound

$100\,dB$ to $120\,dB$, the sound level range where hearing discomfort and pain begin.

Loudness

The subjective or apparent strength of sound to the human listener.

Direct Sound

The portion of a sound wave that travels directly along the line-of-sight path from the source to the listener.

Early Reflections

Sound reflections that strike surfaces and reach the listener within $1/20$ of a second ($0.05\,s$) of the direct sound, merging with it.

Echo (Late Reflection)

A distinct sound reflection that arrives at the listener later than $1/20$ of a second ($0.05\,s$) after the direct sound.

Flutter Echo

A rapid succession of echoes caused by sound bouncing back and forth between two parallel reflective surfaces.

Reverberation

The persistent accumulation of many overlapping reflections in an enclosed space starting around $1/5$ second after direct sound.

Acoustic Diffusion

The scattering of sound reflections off non-flat surfaces causing sound waves to rapidly disorganize.

Decay Time (RT-60)

The time in seconds required for reverberating sound to drop by $60\,dB$ after the source stops.

Sound Absorption

The dissipation of sound energy when striking a fibrous or porous material, converting sound energy into heat.

Sabin

A unit of sound absorption equivalent to $1\,sq\,ft$ of perfectly absorptive surface.

Noise Reduction Coefficient (NRC)

A rating representing the percentage efficiency of a material surface to absorb sound.

Background Noise

Unwanted, undesirable, and interfering ambient sounds present in a listening space.

Noise Floor

The measure of background noise strength in an enclosed room, expressed in decibels ($dB$).

Signal-to-Noise Ratio (S/N Ratio)

The difference in sound level in decibels ($dB$) between the intended direct signal and the background noise floor.

Articulation

The degree of clarity of a sound message such that it can be easily and completely understood.

Intelligibility

A measure of sound clarity based on human comprehension of spoken words and messages.

Bright / Lively Room

An acoustic condition in a room characterized by an abundance of treble range reflections.

Dark / Dead Room

An acoustic condition in a room characterized by a lack of sound reflections and reverberance.

Boomy Room

An acoustic room condition where lower frequencies, particularly the male speech range, are excessively reverberant.

Psychoacoustics

The branch of science studying how the human brain comprehends and makes sense of heard sound.

Audiology

The science and clinical practice of amplifying or improving human hearing perception.

Hertz (Hz)

The SI unit of frequency, equivalent to cycles per second ($cps$).

Sound Spectrum

A plot or graph displaying sound level measured across different frequencies.

Sonic Color

The spectral emphasis shift of a complex sound (e.g., warm, cold, or nasal).

Ultrasonics

Sound frequencies above the range of human hearing, greater than $20000\,Hz$.

Infrasonics

Sound frequencies below the threshold of human hearing, less than $20\,Hz$.

Octave

A frequency interval where the upper limit is exactly twice the lower limit.

Voicing

The process of integrating direct, early, and late reflections with reverberation to define optimal acoustic room conditions.

Acoustician

An acoustical engineer formally trained and experienced in voicing rooms.

Rarefaction

The instantaneous local reduction in density of air or gas resulting from the passage of a sound wave.

Wavelength

The physical distance between two consecutive crests or compressions of a sound wave.

Diffraction of Sound

The bending of sound waves around physical obstacles or through openings.

Standing Wave

A resonant wave pattern created when a sound's wavelength equals one of the room's dimensions.

Speed of Sound in Steel

$4900\,m/s$ or $16000\,ft/s$.

Speed of Sound in Concrete

$3700\,m/s$ or $12100\,ft/s$.

Speed of Sound in Wood

$3300\,m/s$ or $10825\,ft/s$.

Resonance

The intensification of sound produced when a body vibrates sympathetically with another originating sound source.

Porous Absorbent

A soft acoustic absorbent material best suited for lower band frequencies.

Panel Absorber

An acoustic absorber consisting of two material layers separated by an airspace, with a porous outer face.

Cavity Resonator

An absorber consisting of an enclosed body of air connected by a narrow neck, absorbing sound at its resonant frequency.

Reverberation Time Formula

$RT = 0.05 V / (a_1 s_1)$, where $V$ is room volume in $cu\,ft$ and $a_1 s_1$ is total absorption in sabins.

Transient Sound

Direct sound that stops instantly when the originating vibrating body stops.

Near Field

The sound field generally within one wavelength of the lowest frequency produced by a sound source.

Free Field

The sound field existing between the near field and reverberant field where sound intensity follows the inverse square law.

Reverberant Field

The sound field near large room boundaries where reflected sound dominates and approaches a uniform condition.

Inverse Square Law

A physical law stating that sound intensity is inversely proportional to the square of the distance from the source.

Phon

The unit of loudness level.

Creep / Crawl

The reflection of sound waves along a continuous smooth curved surface.

Sound Foci

The concentration of reflected sound waves at a specific focal point from a concave surface.

Soporific Effect

The relaxing or sleep-inducing effect produced by a continuous low-steady sound.

Masking of Sound

The phenomenon where a sound is rendered inaudible or covered up by another sound.

Music Therapy - Response Approach

A therapeutic approach focusing on the mind and body's reaction to music heard from an external source.

Music Therapy - Expression Approach

A therapeutic approach focusing on emotional healing through the active creation of music.

Max Sight Line Clearance (Speech)

A minimum clearance of $3\,inches$ provided between the sightline from one row to the next row.

Max Horizontal Seating Angle (Speech)

Audience seats should be positioned within a maximum angle of $140^\circ$ relative to the speaker.

Max Path Difference (Speech)

The reflected sound path should not exceed the direct sound path by more than $50\,ft$ ($15\,m$).

Optimal Room Volume for Speech

The ideal volume for speech halls is $100\,cu\,ft$ ($2.83\,m^3$) per seat.

Acoustical Clouds

Absorbent panels hung from ceilings at a depth of not less than $2\,ft$ ($0.61\,m$) to absorb sound.

Definition in Music

The clarity with which each individual instrument can be distinguished within an ensemble.

Balance in Music

The correct loudness ratio maintained between different instrument sections of an orchestra.

Blend in Music

The merging of sound from multiple instruments into a homogeneous musical source.

Omnidirectional Microphone

A microphone equally sensitive to sounds arriving from any direction.

Directional Microphone

A microphone primarily sensitive to sound arriving from one specific direction, reducing feedback.

High-Level Sound System

A sound reinforcement system using a single high-power loudspeaker mounted above the speaker.

Low-Level Sound System

A sound system using multiple distributed low-volume loudspeakers located throughout a hall.

Wind Gradient

The difference in wind velocity occurring at varying heights above the ground level.

Temperature Gradient

The variation in air temperature at different elevation levels above the ground.

Airborne Sound Insulation

Acoustic treatment designed to prevent the transmission of sound originating in the air (e.g., voices).

Impact Sound Insulation

Acoustic treatment designed to isolate impact noises generated on structural surfaces (e.g., footsteps).

Resiliency Principle

A structural design concept where a building yields flexibly with vibration to prevent structural failure.

Class 1 Insulation (Lighting)

Luminaires with a terminal for a protective conductor connected to all metal parts that could carry current in a fault.

Class 2 Insulation (Lighting)

Luminaires built with double or total insulation featuring no exposed current-carrying metal parts.

Class 3 Insulation (Lighting)

Luminaires operated with safety extra-low voltage (SELV) under $42\,V$.