BUILDING UTILITIES 3 DEPTALS

Low Pressure Sodium

lamps are similar in many ways to fluorescent lamps as they are both low pressure discharge lamps. All the differences in characteristics stem from the use of ______ in the discharge tube rather than mercury.

Sound Absorption Coefficient

The total absorption in a room, the "room constant," measured in a unit called sabins, is not only the result of the absorption coefficient of the surfaces, but also of the total surface area. More-absorbent surfaces attenuate sound energy through loss to friction, but so do more surfaces of the same absorption profile.

Coefficient of Utilization (CU)

The usable Initial footcandle or lux is equal to the footcandle produced by the____.

Complex Sound

The variation in pressure caused by speech, music, or noise is shown below. Most sounds in the everyday world are complex, consisting of a variety of pressures which vary with time. The threshold of hearing for humans is one millionth of normal atmospheric pressure.

Metal Halide

These lamps were developed as a way of improving the performance of high-pressure mercury lamps in terms of their color appearance and light output.

Reflection, diffraction and scattering

They are all possible without energy loss. In practice, some absorption of sound energy occurs for reflection from all surfaces, while some materials are highly absorbent.

Stationary luminaires

They are an integral part of the architecture. Occasionally it is possible to vary light direction, but rigid mounting usually means that the light direction is also fixed.

Motion Sensors

They are automatic switches that turn lights on when motion is detected and leave them on until some designated time after the last motion occurs.

Air-handling downlights

They are available as air-return luminaires. They represent a dual function solution comprising lighting and air-conditioning and make for harmonious ceiling design.

Dimmers

They are control devices that vary the light level and power to lights.

Ceiling washlights

They are designed for brightening or lighting ceilings and for indirect ambient lighting.

Louvered luminaries

They are designed for linear light sources such as fluorescent lamps or compact fluorescent lamps.

Induction

They are essentially gas discharge lamps that do not have electrodes.

Adjustable luminaires

They are generally direct luminaires that can be adjusted to throw light in directions other than down. These include track lights, floodlights, and accent lights

Sound Waves

They are longitudinal waves (i.e involve oscillations parallel to the direction of the wave travel) that propagates through a medium (e.g. air, water, iron)

Lighting fixtures

They are luminaires that are permanently attached to a building. In other words, a table lamp is a luminaire but not a fixture.

Floor washlights

They are mainly used for lighting hallways and other circulation zones. They are mounted in or on the wall at relatively low levels.

Sight Line Basics

They are normally drawn to converge at a point on stage called the arrival point of sight APS. Audiences should be able to hear and to see clearly and comfortably to fully perceive the intended effects of performances

Direct-indirect louvered luminaires

They are suspended from the ceiling or mounted on the wall. They produce a direct component on horizontal surfaces beneath the luminaire and at the same time light the ceiling and provide diffuse ambient lighting

Light structures

They are systems comprising modular elements that take integrated luminaires.

Spotlights

They are the most common form of movable luminaires. They illuminate a limited area, with the result that they are rarely used for ambient lighting but predominantly for accent lighting

Relay systems

They are typically used in large commercial and institutional buildings like high-rise offices, convention centers, and airports.

Inverse Square Law (Free Field Condition)

They are virtually spherical and expand outward from the source as shown below. A point source has physical dimensions of size that are far less than the distance an observer is away from the source.

Movable Luminaires

They can be used in a variety of locations; they are generally used in track systems or in light structures.

Electronic Control System

This allows precisely defined light scenes to be recalled at the touch of a button, or a change of light scene to be programmed to take place over a given period of time.

Concave Reflector

This can focus sound, causing hot spots and echoes in the audience seating area. Because concave surfaces focus sound, they also are poor distributors of sound energy and therefore should be avoided where sound-reflecting surfaces are desired (e.g., near stage, lectern, or other source locations in rooms).

Non staggered seating layouts

This cannot achieve satisfactory conditions for every-other-row vision.

Luminous Intensity

This describes the quantity of light that is radiated in a particular direction. This is a useful measurement for directive lighting elements such as reflectors.

Energy management systems

This employs a computer to control many relay panels as well as mechanical motors, dampers, and so on.

Preset Dimming Systems

This have a number of _____, usually in cabinets, that are designed to work together to create scenes of light. These complex systems are used in hotel function spaces, airports, convention centers, casinos, and other facilities where a number of rooms or spaces are controlled from a central computer-based preset controller.

Thermoluminescence

This is exhibited by some materials when they are heated. The materials give out much more light than would be expected due to black body radiation. The best-known practical use of the method of light production is the mantle used in some types of gas lamps.

Watts per square meter method

This is mainly a rough calculation or rule of thumb. Estimates or calculation is done by specifying an allowance of watts per square meter of an area to be illuminated.

Luminance

This is the only basic lighting parameter that is perceived by the eye. It describes on the one hand a light source's impression of brightness, and on the other, a surface and therefore depends to a large extent on the degree of reflection (colour and surface).

High Pressure Sodium

This lamp generates light in a discharge through _____ vapor at high pressure. As the vapor pressure of _____ in a lamp rises the spectrum at first broadens and then it splits in two with a gap appearing at about 586 nm.

Fluorescent

This lamp works by generating ultraviolet radiation in a discharge in low pressure mercury vapor. This is then converted into visible light by a phosphor coating on the inside of the tube. The electric current supplied to the discharge has to be limited by control gear to maintain stable operation of the lamp.

Point to point or Inverse Square Law Method

This method is applicable where illumination at a point due to one or more sources of light required and the candle powers of the sources in the particular direction under consideration being known.

Lumen or Light Flux Method (Zonal Cavity Method)

This method is suitable for the situation where the light source produces approximately uniform illumination on the working plane.

Radioluminescence

This occurs in a similar manner to luminescence, but the primary source of the activation energy is particles or gamma rays emitted by a decaying nucleus of a radioactive atom.

Absorption

This removes acoustic energy. there are three possible mechanisms: porous ____, panel _____ and helmholtz resonance.

Light Emitting Diode

This type of electric light are available in a wide variety of sizes, colors and power ratings and development is proceeding at a rapid rate. These generally have a long life and may last up to 100,000 hours.

Decibel

To measure differences or to measure sound (or other) amplitudes. In both cases, the choice of a logarithmic scale overcomes the problem of large numbers. The magnitude of the decibel for differences can be illustrated by some examples.

Switches

Turn lights on and off

Candela

Unit of measurement of luminous intensity

Convex Reflector

_______, hard-surfaced building elements, if large enough, can be most effective as sound-distributing forms. The reflected sound energy from convex surfaces diverges, enhancing diffusion, which is highly desirable for music listening. In addition, reflected sound from convex surfaces is more evenly distributed across a wide range of frequencies.

Reflection

______from a finite surface depends on the relationship between the size of the reflector and the wavelength of sound. Perfect _____occurs at high frequencies, whereas when the frequency is lowered, less and less energy is reflected along the geometrical _____ path. The distance of the reflector from the source and receiver also proves to be significant.

Electric discharges

An electric discharge is an electric current that flows through a gas.

Laterally staggered seating layouts

It can achieve satisfactory every-other-row vision for back-to back seat dimension B of 40 in for continental seating and 36 in for radial and parallel aisle seating.

Luminous Flux

It describes the quantity of light emitted by a light source.

Illuminance

It describes the quantity of luminous flux falling on a surface.

Side lighting

It employs vertical fenestration (usually windows) to introduce natural light.

Daylighting Control Systems

It features a photoelectric sensor that generates a signal to dim interior lights when adequate daylight enters the room through windows and skylights.

Tungsten Halogen

It gives off whiter light and last longer than standard incandescent lamps.

Directivity

It is a measure of the directional characteristic of a sound source. It is often expressed as a Index in decibels, or as a ______dimensionless value of Q. This is an important aspect of a sound source, especially in a reverberant field.

Timer

It is a switch that turns lights off automatically after a certain period.

Ray Diagram

It is an acoustical analogy to the specular reflection of light where the angle of incidence ∠i of an impinging sound wave equals the angle of reflection ∠r, with angles measured from the perpendicular to the surface.

Time Clock

It is an electromechanical clock that opens and closes a circuit at specific times each day.

Lighting Control Console

It is an electronic device used in theatrical lighting design to control multiple stage lights at once.

Daylighting

It is an excellent light source for almost all interior spaces. It is best for offices, schools, and workspaces requiring a lot of light and for public spaces such as malls, airports, and institutions.

Luminaires

It is any device that includes a lamp holder and the means of electrification and support for that device.

Diverging Wave

It is one where the sound energy is spread over a greater and greater area as the wave propagates away from the sound source.

Incandescent

It is operated by heating a filament in the lamp to a high temperature, so that it emits light. The hotter the filament, the whiter the light.

Spherical Wave

It is produced by a sound source which radiates sound energy equally in all directions e.g. a monopole source.

Standing Wave

It is produced by the constructive interference of two or more sound waves which gives rise to a pattern of pressure maxima and m inima which is stable with time e.g. ______can exist in tubes, musical instruments, organ pipes and in larger volumes such as rooms.

Reverberation Time

It is simply defined as the persistence of sound.

Diffraction

It is the bending or "flowing" of a sound wave around an object or through an opening. (x < λ)

Audible resonance

It is the emphasis of sound energy at particular frequencies. It can occur in small rooms entirely finished with sound-reflecting materials when the dimensional ratios are whole numbers (e.g., cube). This phenomenon is sometimes referred to as the "bathroom tenor" effect.

Lighting design

It is the planning of our visual environment, and the basis of each lighting concept is the analysis of the project

Luminous Efficiency

It is the ratio of the luminous flux to the electrical power consumed (lm/W). It is a measure of a light source's economic_______.

NR

It is the reduction in reverberant noise level. This does not affect the noise level very near the source of sound in a room.

Reflection

It is the return of a sound wave from a surface.

Diffusion

It is the scattering or random redistribution of a sound wave from a surface. It occurs when the surface depths of hardsurfaced materials are comparable to the wavelengths of the sound. (x = λ)

Sound

It is the senstation perceived by the human ear resulting from rapid fluctuations in the air pressure. These fluctuations are usually created by some vibrating object which sets up longitudinal wave motion in the air.

Pure Tone

It is vibration produced at a single frequency.

Asymmetric louvered luminaires

Predominantly radiate light in one direction only. They can be used for the uniform lighting of walls or to avoid glare caused by light projected onto windows or doors.

Qualitative Lighting Design

Project Analysis > Utilization of space > Qualitative Concept

Directional spotlights

Provide accent lighting of specific areas or objects. By redirecting the light beam they can be used for different lighting tasks. Their light distribution is narrow to medium.

Chemiluminescence

Some chemical reactions can produce light directly, not via the heat the reaction creates. The process is used by some living organisms to generate light; the best-known example being the glow worm.

Electroluminescence

Some materials will convert electricity into light directly.

Cathodoluminescence

The energy driving the phosphor is an electron that has been accelerated away from a cathode. This process is the means by which light is generated in a cathode ray tube.

Three characteristics describe the physics of sound

• Sound level (or energy, strength, amplitude, loudness) • Frequency (or pitch, tone, wavelength) • Propagation (or path, elapsed time)

Direct luminaires

> Emit light downward. These include most types of recessed lighting, including downlights and troffers. > Tend to be more efficient by distributing light directly onto the task area. They generally create dark ceilings and upper walls that can be dramatic but also uncomfortable due to high contrast.

Diffuse luminaires

> Emit light in all directions uniformly. These include most types of bare lamps, globes, chandeliers, and some table and floor lamps. > Tend to create broad general light that often is considered glaring due to lack of side shielding.

Direct/indirect luminaires

> Emit light upward and downward but not to the side. These include many types of suspended luminaires as well as some table and floor lamps. > They are often a good compromise between the efficiency of direct lighting and the comfort of indirect lighting.

Indirect luminaires

> Emit light upward, bouncing light from the ceiling into a space. These include many styles of suspended luminaires, sconces, and some portable lamps. > Tend to create comfortable, low-contrast soft light that psychologically enlarges space.

Asymmetric luminaires

> They are usually designed for special applications. > They are chosen when accent lighting of objects or surfaces is desired.

Quantitative Lighting Design

> Watts per square meter method > Lumen or Light Flux Method (Zonal Cavity Method) > Point to point or Inverse Square Law Method

Frequency

A pure tone has a single frequency associated with it. All musical instruments however produce complex sounds made up of several frequencies, though the lowest of these normally determines the pitch, the name given to the perceived frequency. If a surface is vibrating, the frequency of vibration is the number of cycles per second, though this is now expressed in hertz (Hz).

Sound Level

A sound is made when an oscillating membrane disturbs the molecules in an elastic medium—and that disturbance is heard. While sounds may travel through solids or liquids, in the domain of architectural acoustics, we generally skew our discussion to the elastic medium of air (structure borne sound notwithstanding).

Uplights

Emit light upwards

One lumen/steradian

Equivalent of Candela

Privacy

Extensively glazed buildings can present ____ problems, particularly on the ground floor. Concerns about _____ can lead to blinds being closed at all times with a consequent lack of daylight and view out.

Argand lamp

Francois Argand constructed a lamp that was to be named after him

Unobstructed sight lines

From all seats to the front of the forestage allow full view of performers and unobstructed propagation of the direct sound.

Washlight

Have asymmetrical lighting distribution, which not only directs the light vertically downwards, but also directly onto vertical surfaces.

Double-focus downlights

Have similar properties to conventional downlights, but the special form of the reflector allows high luminous efficiency even though the ceiling aperture is small.

Sightline design. P is the setting-out point for the Stalls seating.

In an enclosed space, the direct sound of course decreases in level in the same way as outside. The major concern for the direct sound in auditoria is that it is not affected by other audience members. This requirement is generally satisfied if there are adequate sightlines to the stage.

High Pressure Mercury

In this type of lamp, a discharge takes place in a quartz discharge tube containing _____ vapor at high pressure (2 to 10 atmospheres).

Top lighting

It behaves as direct electric lighting does by radiating light downward.

Fiber optic systems

Allow light to be transported at various lengths and around bends and curves. The actual light source may be located at a considerable distance from the light head.

Historically dominant auditorium plan forms

(a) classical Greek theatre (fan-shape plan); (b) classical Roman arena; (c) baroque theatre (horseshoe plan); (d) nineteenth-century rectangular concert hall

Types of Lighting

1) General Lighting (2) Task Lighting (3) Accent lighting (4) Ambient Lighting (5) Mood lighting

Diffraction

A textured surface will provide some scattering of sound, but the degree of texturing must be high for efficient scattering. The general principle is that the deeper the scattering treatment, the lower the frequency down to which the surface will scatter sound.

Thermal

Daylight admitted to a building represents a heat load. In winter this may be useful but in summer it can represent an additional cooling load.

Reverberation Time

Defined as the persistence of sound.

Downlights

Direct light predominantly downwards

Sound Propagation

Direct sound decays at the same rate inside as outside, shedding six decibels per doubling of distance because the same sound energy is spread over four times the area every time the distance is doubled. What differs is the reflected sound off the room boundary surfaces inside. Depending on materiality, sound energy hitting a surface will reflect off a surface as the spreading sound‐front sphere folds in on itself with each successive reflection.

Constancy

One of the most important tasks of perception is to differentiate between constant objects and changes in our surroundings in the continuously changing shapes and distribution of brightness of the image on the retina.

Hard, sound-reflecting enclosure

Outdoors near the sound source can greatly improve listening conditions by reflecting sound energy toward the audience and by shielding the audience from noise sources located behind the enclosure.

Flutter Echo

Repetitive interreflection of sound energy between opposing parallel or concave sound-reflecting surfaces. _____ is normally heard as a high-frequency ringing or buzzing

Velocity of Sound Waves Propagation

Sound travels at a velocity that depends primarily on the elasticity and density of the medium. In air, at normal temperature and atmospheric pressure, the velocity of sound is approximately 1130 feet per second (ft/s), or almost 800 mi/h. This is extremely slow when compared to the velocity of light, which is about 186,000 mi/s, but much faster than even hurricane winds.

Intensity

The _____ from a point source outdoors at a distance d away is the sound power of the source divided by the total spherical area And^ of the sound wave at the distance of interest.

Visual

The _____problems of daylighting are glare and veiling reflections. Glare is caused by a direct view of either the sun or the bright sky

Amplitude

The amplitude of a sound wave is determined by the magnitude of the pressure fluctuation. But the range of pressures to which our ears can respond exceeds a ratio of one to a million and the response is not linear.

Room Noise Reduction

The buildup of sound levels in a room is due to the repeated reflections of sound from its enclosing surfaces. This buildup is affected by the size of the room and the amount of absorption within the room

Echoes

The distinct repetition of the original sound and is sufficiently loud to be clearly heard above the general reverberation and background noise in a space.

Pitched-Rood Flutter Echo

The echo phenomenon which occur in rooms with non-parallel walls.

Frequency of Sounds

The number of cycles per second is called the ______, f. The unit of frequency is the Hertz. 1 Hertz = 1 cycle/sec. The time taken for the oscillation to repeat itself is known as the period, T.

Luminescence

The process involves a material absorbing radiation and then re-emitting light.

Law of Gestalt

The process of identifying this object in the profusion of continuously changing stimuli on the retina is no less problematic than the perception of objects.

Optimum Reverberation Time

The ranges, based on the experience of normal-hearing listeners in completed spaces, are extended by dashed sections at the ends of the bars to indicate the extreme limits of acceptability.

Steeply sloped seating

The sound level outdoors falls off primarily with distance. An overhead sound-reflecting panel or ceiling, as shown by the illustration, can provide reflected sound to reinforce the direct sound.

Speed of Sound

The speed of any mechanical wave depends on the both the inertial property of the medium (stokes kinetic energy) and the elastic property (store potential energy).

Photometrics

The theory of how to measure light - and illuminances - through Boguer and Lambert in the 18th century, the most essential scientific principles for workable lighting engineering were established

Incandescence

When an object is heated to a high temperature, the atoms within the material become excited by the many interactions between them and energy is radiated in a continuous spectrum.

Plane Wave

When corresponding wavefronts of a sound wave propagate parallel to each other then the sound wave is known as a _______ e.g. the sound wave produced by a piston oscillating in a long cylinder.

Frequency

When sound includes abundant high‐pitched or treble energy, it is said to be heavy on high‐frequency content, and when sound includes abundant low pitched or bass energy, it contains ample low‐frequency content.

Progressive Wave

When there is a transfer of energy in the direction of propagation of the sound wave the wave is designated as ______.

Flat Reflector

____, hard-surfaced building elements, if large enough and oriented properly, can effectively distribute reflected sound. The reflector shown below is tilted slightly to project sound energy toward the rear of an auditorium.

Air-handling louvered luminaires

designed to handle supply air and return air and provide a more harmonious ceiling layout. They can be provided with connections/outlets for supply air, return air, or both supply air and return air.