Term
| Example of how acoustics affect quality of design: |
|
Definition
| Spaces too noisy/reverberant are distracting @ best, unusable @ worst. Classrms, etc. where sounds not audible are unsuitable too |
|
|
Term
| How can acoustic quality of a room be controlled? |
|
Definition
| w/ space planning, design of walls & ceilings, & selection of finishes |
|
|
Term
| 3 basic qualities of sound: |
|
Definition
| 1) Velocity 2) Frequency 3) Power |
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|
Term
|
Definition
| Depends on medium in which sound is traveling & temp of medium |
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|
Term
|
Definition
| # of cycles completed per sec & measured in Hertz |
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|
Term
|
Definition
|
|
Term
| What sounds have higher / lower frequencies? |
|
Definition
| high notes/pitches:higher, bass notes: lower |
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|
Term
|
Definition
| Quality of acoustic energy as measured in watts. What people perceive as loudness |
|
|
Term
| What is vast range of sound power human ear sensitive to? |
|
Definition
| from approx 10-16 watts per/sq centimeter to 10-3 watts per sq cent |
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|
Term
| WHat is the sensation of hearing proportional to? |
|
Definition
| logarithm of source intensity |
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Term
|
Definition
| used in acoustical descriptions & calculations. o Conveniently relates actual sound intensity to way humans experience sound |
|
|
Term
| WHat decibel is threshold of hearing & thresh hold of pain? |
|
Definition
| 0 = threshold of human hearing, 130 = threshold of pain |
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Term
| What can decibels measurements be useful in evaluating? |
|
Definition
| evaluating effects of increased/decreased decibel levels in design solutions. Example: Will it be worth spending the money to change something towards improvement…ie will it make a difference |
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|
Term
| What does human sensitivity to sound vary with? |
|
Definition
| age, physical condition of ear, background, & other factors |
|
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Term
| How healthy young person hears sounds: |
|
Definition
| in range of 20-20,000Hz & most sensitive to freq in 3000-4000hz range. |
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|
Term
| Speech composed of sounds primarily in range: |
|
Definition
| 125-8000Hz (most range 200-5000) |
|
|
Term
| Which frequencies is human ear less sensitive to? |
|
Definition
| to low freq than middle & high freq for sounds of equal energy |
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|
Term
| What do most common sound sources contain? |
|
Definition
| energy over wide range of frequency. |
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Term
| What must be taken into account in building acoustics? |
|
Definition
| sound frequencies since important variable in how sound is transmitted or absorbed |
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|
Term
| How is the measurement & analysis of frequencies divided? |
|
Definition
| into 7 octave frequency bands indentified by center frequency |
|
|
Term
| WHat are the 2 basic problems in controlling noise: |
|
Definition
| 1). Preventing or minimizing transmission of sound from 1 space to another. 2). Reducing noise wi/ a space |
|
|
Term
| How is the transmission of sound retarded? |
|
Definition
| primarily by mass of the partition. Stiffness, or rigidity, of partition also imp |
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Term
| Importance of stiffness, or rigidity of partition in retarding noise transmission: |
|
Definition
| 2 partitions of same weight per sq/ft, 1 w/ less stiffness will perform better than other |
|
|
Term
| 2 important concepts in noise reduction: |
|
Definition
| 1)Transmission Loss 2) Actual noise |
|
|
Term
|
Definition
| takes into account only the loss through the partition |
|
|
Term
|
Definition
| dependent not only on transmission loss but also on area of partition separating 2 spaces & absorption of surfaces in the “quiet” rm |
|
|
Term
| How can actual noise be reduced? |
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Definition
| increasing transmission loss of partition, by increasing absorption in “quiet” rm, by decreasing area of common wall between rms, or by some combo of all 3 |
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Term
| WHat is used to simplify selection of wall construction & other building components? |
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Definition
| single-# rating is often used to rate transmission loss of construction - known as sound transmission class |
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|
Term
| What does a higher sound transmission class rating mean? |
|
Definition
| better barrier in stopping sound |
|
|
Term
| What do sound transmission class ratings represent? |
|
Definition
| ideal loss through barrier under lab cond |
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|
Term
| What is it important to remember about actual construction materials used on site that were rated under sound transmission class? |
|
Definition
| Partitions, floors, & other const components built in field seldom const as well as those in lab. Breaks in barriers such as cracks, elec outlets, doors, etc. will significantly lessen overall noise reduction |
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|
Term
| What should be done when acoustical security is critical? |
|
Definition
| transmission loss & selection of barriers should be calc using values for various freq rather than single STC avg value |
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|
Term
|
Definition
| Allowed in some materials. It stops most frequencies but allows transmissions of certain range of frequencies. |
|
|
Term
| Is background noise totally undesirable? |
|
Definition
| Not undesirable cuz some noise necess to avoid feelings of “dead” space & help mask other sound |
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|
Term
| WHat does the acceptable amount of background noice vary with? |
|
Definition
| type of space & frequency of sound |
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|
Term
| What types of background noises do people tend to tolerate more of? |
|
Definition
| higher levels of low freq sound than high freq sound |
|
|
Term
| WHat are background noise variables consolidated into? |
|
Definition
| set of noise criteria curves relating freq in 8 octave bands to noise level |
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|
Term
| Where are noise criteria ratings for various types of spaces listed? |
|
Definition
|
|
Term
| What can noise criteria curves be used to do? |
|
Definition
| specify max amount of continuous background noise allowable in space, to est min amount of noise desired to help mask sounds, & to eval existing condition |
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|
Term
| What is sound absorption used to control: |
|
Definition
| unwanted sound reflections (noise), improve speech privacy, & decrease/increase reverberation. |
|
|
Term
| What is absorption of materials defined by? |
|
Definition
| coefficient of absorption, which is ratio of sound intensity absorbed by mat to total intensity reaching the mat |
|
|
Term
| What is the maximum coefficient ot absorption possible? |
|
Definition
|
|
Term
| When are materials considered reflective & when considered sound absorbing? |
|
Definition
| Gen, mat w/ coefficient below .2 is considered to be reflective, & 1 w/ coefficient above .2 is considered sound absorbing |
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|
Term
| How can designer find material's coefficient of absorption? |
|
Definition
| they are published in manufacturer's tech literature |
|
|
Term
| What does the coefficient of absorption vary with? |
|
Definition
| feq of sound, & some mats better @ absorb some freq than others |
|
|
Term
| Noise reduction Coefficient (NRC): |
|
Definition
| Single # used for convenience. Avg of mats absorp coefficients @ 4 freqs of 250, 500, 1000, & 2000Hz rounded to nearest mult of .005 |
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|
Term
| What does the total absorption of material depend on? |
|
Definition
| its coefficient of absorption & area of material |
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|
Term
| How is the total absorption of a room figured? |
|
Definition
| It is the sum of various individual materials absorption since most rooms have several materials w/different areas |
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|
Term
| How can designers avoid creating a space that is too "live" & noisy? |
|
Definition
| Avoid designing rms w/ hard reflective surfaces on walls, floor, & ceil |
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|
Term
| Is doubling of amount of absorption in a room affective? |
|
Definition
| No since this results in a noise reduction of only 3 decibels, so it's hardly noticeable |
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|
Term
| How is an attempt at noise reduction done affectively? |
|
Definition
| must increase total absorp by @ least 3 xs to change reduction by 5db, which is noticeable |
|
|
Term
| where can absorptive materials be placed to get the most affect? |
|
Definition
| , but ceil treat for sound absorp more effective in lrg rms, while wall treatment more effective in sml rms |
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|
Term
|
Definition
| Prolongation of sound as it repeatedly bounces off hard surfaces. |
|
|
Term
| What does reverberation affect? |
|
Definition
| Affects intelligibility of speech & quality of music |
|
|
Term
|
Definition
| time it takes sound level to decrease 60 db after source has stopped producing sound |
|
|
Term
| What must reverberation time be appropriate for? |
|
Definition
|
|
Term
| How can reverberation be controlled? |
|
Definition
| by modifying amt of absorptive or reflective finishes in space |
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|
Term
| 3 pirmary ways sound can be controlled w/i a space: |
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Definition
| 1)Reduce level of loudness of sound source 2)By modifying absorption in a space 3)By introducing nonintrusive background sound to mask unwanted sound |
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|
Term
| Why is reducing the level of loundness of sound source not always possible? |
|
Definition
| if sound created by fixed piece of machinery, peeps, or some similar situation |
|
|
Term
| What can be done If source is noise from outside or adjacent rm? |
|
Definition
| , transmission loss of enclosing walls can be improved |
|
|
Term
| What happens if it's a machine producing noise? |
|
Definition
| can often be enclosed or modified to reduce its noise output |
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|
Term
| When is modifying absorption in space most useful? |
|
Definition
| when prob rm has lrg % of hard, reflective surfaces |
|
|
Term
| Why is introducing nonintrusive background sound desirable? |
|
Definition
| it can mask unwanted noise |
|
|
Term
| Where can unwanted noise come from? |
|
Definition
| steady hum of HVAC syst, business machines, traffic, conversation, or other sources |
|
|
Term
| what do the decibels of nonintrusive background sound do? |
|
Definition
| reduce decibels heard of distractive noise |
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|
Term
| white sound, random noise, or acoustic perfume: |
|
Definition
| Purposefully introducing carefully controlled sound into space rather than relying only on random background noise |
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Term
| How can/way white sound, random noise, or acoustic perfume be introduced to space? |
|
Definition
| Speakers placed into ceiling & connected to sound generator, which produces continuous, unnoticeable sound @ Particular levels across freq spectrum |
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|
Term
| WHere is white sound, random noise, or acoustic perfume often used? |
|
Definition
| open offices to provide speech privacy & help mask office machine noise |
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|
Term
| What is the control of sound transmission through a barrier primarily dependent on? |
|
Definition
| barrier’s mass & to a lesser extent on its stiffness |
|
|
Term
| 3 methods to build sound resistant partition: |
|
Definition
| 1) add mass to wall 2)place insulation wi/stud cavity 3) Resistant channels can be used as furring strips on one side of partition |
|
|
Term
| How can mass be added to a wall: |
|
Definition
| by using heavy mat for partition, such as masonry, or by using more thant 1 layer of gypsum wallboard |
|
|
Term
| What do partitions w/ high sound transmission class generally have? |
|
Definition
| double layer of wallboard on one or both sides of stud |
|
|
Term
| hat does insulation wi/ a stud cavity do? |
|
Definition
| Absorbs sounds (reduces energy) that transmitted through one layer of wall before reaches other |
|
|
Term
| What does design of resistant channels on side of partition do? |
|
Definition
| , only 1 leg of channel touches stud so wallboard “floats” and dampens sound striking it rather than transmitting it to the stud |
|
|
Term
| where do gaps occur in the barrier that must be sealed? |
|
Definition
| Edges of floor, ceiling, and intersecting walls must be caulked |
|
|
Term
| What should be avoided in a barrier if possible? |
|
Definition
| Penetrations but when necessary must be sealed |
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|
Term
| Examples of penetrations in a barrier: |
|
Definition
| elec outlets shouldn’t be placed back to back but staggered in separate stud spaces and caulked |
|
|
Term
| What do Pipes, ducts, & similar penetrations provide path for ? |
|
Definition
| for both airborne sound & mech vibration & shouldn’t be rigidly connected to barrier |
|
|
Term
| WHat should be done with gaps between ducts, pipes, & partition? |
|
Definition
| should be sealed & caulked |
|
|
Term
| Is it wise to use a construction w/ a lower STC rating than barrier itself? |
|
Definition
| should be avoided or given special treatment because it will decrease overall rating of the barrier |
|
|
Term
| Common use of construction item w/ lower STC rating than barrier: |
|
Definition
| Doors placed in otherwise well-built sound wall are common prob |
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|
Term
| How can doors placed in well-built sound wall be dealt with? |
|
Definition
| 1) Perimeter should be completely sealed w/ weather stripping specifically designed for sound sealing @ jamb & head & w/ threshold or automatic door bottom @ the sill. 2)Door itself should be as heavy as poss, preferably solid-core wood door |
|
|
Term
|
Definition
| Piece of hardware that drops a seal from the door to the floor or threshold as door closes |
|
|
Term
| How can interior glass light be acoustically designed? |
|
Definition
| w/ laminated glass in resilient framing |
|
|
Term
| How is laminated glass acoustically better? |
|
Definition
| provides more mass, & plastic interlayer improves damping characteristics of barrier |
|
|
Term
| If additional transmission loss is required, what can be done with interior glass lights? |
|
Definition
| 2 or more layers can be installed w/ air gap between them |
|
|
Term
| What do flanking paths for sound to travel include: |
|
Definition
| incl AC ducts, plenums, and hallways should be elim or treated appropriately |
|
|
Term
| What is a critical acoustic concern? |
|
Definition
| Generally providing cert level of privacy while still allowing peeps to talk @ normal level. |
|
|
Term
|
Definition
| : talking may be heard as gen background sound but not easily understood |
|
|
Term
| How is speech privacy achieved in areas divided by full height partitions? |
|
Definition
| usually achieved by sound loss through partitions & proper use of sound absorbing surfaces |
|
|
Term
| What are 5 important factors that all must be present to achieve optimum acoustic environment? |
|
Definition
| 1)Ceiling must be highly absorptive 2)Area must include space dividers that reduce transmission of sound from 1 space to adjacent spaces 3)Other surfaces - floor, furniture, window, & light fixtures must be designed/arranged to minimize sound reflects 4)Activities should be distanced if possible to take advantage of normal attenuation of sound w/distance 5) Area should have properly designed background masking system |
|
|
Term
| What does a highly absorptive ceiling create? |
|
Definition
| “clear sky” condition so sounds not reflected from their source to other parts of space |
|
|
Term
| How can space dividers be designed that reduce transmission of sound? |
|
Definition
| Should have combo of absorptive surfaces to minimize sound reflections placed over a solid liner called septum. |
|
|
Term
| What happens if the right amount of sound absorptive surfaces are provided? |
|
Definition
| masking syst will absorb all sounds in space, not just unwanted sounds. So . Backgrnd sound must then be reintroduced to maintain right bal between speech sound and backgrnd masking noise |
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|
Term
| What type of surfaces does Sound resulting from direct contact of an object w/ a sound barrier occur on? |
|
Definition
| can occur on any surface, but gen occurs on floor & ceil assembly. |
|
|
Term
| What is direct contact of an object w/ a sound barrier usually caused by? |
|
Definition
| by footfalls, shuffled furn, & dropped objects |
|
|
Term
| How is impact noise quantified? |
|
Definition
| by impact insulation class #, single # rating of floor/ceilings impact sound perform |
|
|
Term
| What does a higher IIC rating mean for a floor? |
|
Definition
| , better floor performs in reducing impact sounds in test freq range |
|
|
Term
| What does a higher IIC rating mean for a floor? |
|
Definition
| , better floor performs in reducing impact sounds in test freq range |
|
|
Term
| How can an IIC value be increased? |
|
Definition
| Increased easily by adding carpet. Also improved by providing resiliently suspended ceiling below, floating finished floor on resilient pads over structural floor, or by providing sound absorbing mat (insulation) in air space between floor & finished ceiling below |
|
|
Term
| What can acoustic performance of a group of spaces or individual rooms be affected by? |
|
Definition
| floor plan layout & size & shape of rm itself |
|
|
Term
| Ideas to help minimize acoustic problems in interior space planning: |
|
Definition
| Plan similar use areas next to each other. Use buffer spaces such as closets & hallways to sep noise-producing spaces when poss. Stagger doorways in halls & other areas to avoid providing straight-line path for noise. Try to locate furn & other potential noise producing objects away from wall separating spaces. Min area of common wall between 2 rms where reduction in sound transmission desired. Avoid rm shapes that reflect or focus sound. |
|
|
Term
| What type of room shapes produce undesirable focused sound? |
|
Definition
| Barrel vaulted hallways & circular rms |
|
|
Term
| What may rooms that focus sound do? |
|
Definition
| also deprive some listeners of useful reflections |
|
|
Term
| WHat 3 methods can be used to acoustically rate all ceilings? |
|
Definition
| 1)Noise Reduction Coefficient 2) Speech Range Absorption 3) Ceiling Attenuation class |
|
|
Term
| Noise Reduction Coefficient: |
|
Definition
| a single number rating of the average, sound absorption of material over a limited frequncy range, including 250, 500, 1000, & 2000 Hertz rounded to nearest multiple of .05. |
|
|
Term
|
Definition
| 0 (no sound absorp) to 1.0 (total absop) |
|
|
Term
| What are acoustical ceiling tiles gen in range of ? |
|
Definition
|
|
Term
| What are the recommended NRC valuses in an open plan office? |
|
Definition
|
|
Term
|
Definition
| Also single# rating but freq range includes 500, 1000, 2000, & 4000 HZ |
|
|
Term
| WHat does the speech range absorption represent? |
|
Definition
| freqs of speech & may be better rating to use in eval & selecting ceiling tiles |
|
|
Term
| Ceiling Attenuation Class: |
|
Definition
| Single # measure of transmission loss through ceiling tiles between 2 closed rms where there’s no wall or barrier above suspended ceiling |
|
|
Term
| What is the ceiling attenuation class given in units of? |
|
Definition
| decibels & similar to sound transmission class |
|
|
Term
| What do most acoustical ceiling tiles have a ceiling attenuation class rating range of? |
|
Definition
| 30db-35db, minimally effective @ blocking sound |
|
|
Term
| How is the CAC rating of tile improved? |
|
Definition
| by using composite tiles that have gypsum wallboard backing |
|
|
Term
| Types of Orthographic drawings: |
|
Definition
| Floor plans, elevations, reflected ceiling plan, and sections – common types |
|
|
Term
| What are orthographic projections used for? |
|
Definition
| To enable 3D objects to be seen in 2D |
|
|
Term
| Why are orthographic drawings ideal for communication if world of paper & computer screens? |
|
Definition
| cuz, using mult orthographic views, even most complex object can be accurately & completely described |
|
|
Term
|
Definition
| view of object seen as though line of sight were simultaneously perp to very pt on face of object. Imagine each signif face of object projected onto flat transparent plane parallel to face of object |
|
|
Term
| How are all pieces of an object shown on orthographic drawings? |
|
Definition
| shown in true relationship w/ other pieces, & scale & proportion are same for multiple views of same object |
|
|
Term
| Where are there no distortion for lines & planes on orthographic drawings? |
|
Definition
| parallel to plane on which view is projected |
|
|
Term
| What happens when a diagonal lineor plane is shown on an orthographic projection? |
|
Definition
| It's foreshortened. Example: top view of building shows foreshortened view of width of room while length shown true to scale |
|
|
Term
| What happens if you scale length of line from eaves to peak of roof in top view> |
|
Definition
| distance is shorter than true length as scaled on side view |
|
|
Term
| Are most orthographic projections drawn to scale? |
|
Definition
|
|
Term
| What do large scales have effect of doing? |
|
Definition
| bringing viewer closer to object so more can be seen |
|
|
Term
| What scale is good for showing very complex construction details? |
|
Definition
|
|
Term
| What can orthographic projection also be used as basis for? |
|
Definition
| some types of 3D dwgs including axonometric dwgs, elevation obliques, & 1-pt sectional perspectives |
|
|
Term
| WHat is an orthographic view of object as seen from? |
|
Definition
|
|
Term
| What is the most common type of plan? |
|
Definition
|
|
Term
| What is a floor plan really? |
|
Definition
| A section since the theory is a horizontal cut made through a building about 5’ above floor. Top portion removed. |
|
|
Term
| After "cut" is made through building for floor plan what happens to remaining? |
|
Definition
| drawn as plan, including what shows on the floor: cutting a sect @ this pt makes possible to show windows, doors, & other openings |
|
|
Term
|
Definition
| View of building seen from above w/o section cut |
|
|
Term
|
Definition
| If some grnd on which building sits, landscaping,walks, drives, and property lines |
|
|
Term
| How is Floor plan section more commonly shown? |
|
Definition
| as just 2 parallel lines Even though Section would show all const mats wi/walls |
|
|
Term
|
Definition
| How walls are drawn on floor plan in many cases. graphic pattern or solid black used to make walls stand out or indicate wall const type. |
|
|
Term
| Openings on a floor plan: |
|
Definition
| All openings also shown, even if bottom edges are above 5’ section cut |
|
|
Term
| What other construction elements may be shown on a floor plan that are above the "5' cut line": |
|
Definition
| kitchen cabinets, ceiling breaks, & shelving. Dashed lines are used for these items to indicate above normal sect cut |
|
|
Term
|
Definition
| Orthographic view of ceiling of rm or building as though there were mirror on floor & you could see through roof to see ceiling’s reflection. As if all pts on ceiling could be projected through roof onto transparent plane above building |
|
|
Term
| WHy are reflected ceiling plan views important? |
|
Definition
| so that orientation of reflected ceiling plan is identical to floor plan |
|
|
Term
| What does a reflected ceiling plan show? |
|
Definition
| const elements that touch plane of ceiling, as well as ceiling itself & objects in ceiling. o So walls that extend to or through ceiling drawn, but low walls aren’t |
|
|
Term
|
Definition
| An orth view of side of an object. Show the length & ht of walls of a room. |
|
|
Term
| What can an elevation show besides vertical dimensions? |
|
Definition
| also types & extent of mats & finishes in rm that can’t be adequately described on dwgs |
|
|
Term
| Are elevations drawn at same scale as floor plan? |
|
Definition
| No. often drawn at lrger scale than floor plans, some horz dims can also be described if not enough rm on plan or if const is complex |
|
|
Term
| What is commonly shown on an interior elevation rather than on plans? |
|
Definition
| Spacing of wall panel joints or width of cabinets |
|
|
Term
|
Definition
| An orthographic view of object after it’s been cut & 1 portion has been removed. May be view through entire building, or through very sml portion of const like front edge of countertop |
|
|
Term
| What cut can be used for a section? |
|
Definition
| Normally vertical slices through objects, can be cut horizontally (as with plans) or any angle that’s convenient to show internal const of something |
|
|
Term
|
Definition
| hidden info about const that can’t be described on plans or elevations. Shows cut through both solids & voids |
|
|
Term
| Typical interior design sections illustrated: |
|
Definition
| lrger scale views through walls, millwork, door frames, & other details |
|
|
Term
|
Definition
| Commonly show complex const info @ relatively large scale. Most details on set of const dwgs are section views of 1 sort or another |
|
|
Term
|
Definition
| the ratio of a measuring unit to the full-size item it represents |
|
|
Term
| Since sections can be complex, what certain graphic techniques can be used to avoid confustion? |
|
Definition
| Solid portions often poched w/ stand mat indications. Voids left blank. Lines separating solid from void drawn very heavy: known as profile lines. To show relationship between mat cut in sect & adjacent const, thin lines used to show elements that occur beyond section cut. |
|
|
Term
|
Definition
| view of an object inclined to the picture plane in such a way that 3 principal axes are foreshortened |
|
|
Term
| What are the 3 types of axonometric drawings? |
|
Definition
| isometric, diametric, & trimetric |
|
|
Term
|
Definition
| : 3D view of object where object tilted in relationship to a picture plane. All lines oblique to picture plane |
|
|
Term
| What do the 3 principal axes of an object in an isometric drawing make? |
|
Definition
| equal angles w/ picture plane, or dwg surface. Makes vert axis of object vert on paper & 2 horz axes form 30 degree angles on paper. Lengths of all 3 principal axes drawn @ same scale |
|
|
Term
| advantages of isometric drawings: |
|
Definition
| quick & easy to draw & can be measured @ any convenient scale |
|
|
Term
| What must be done to floor plans to relate to isometric drawings: |
|
Definition
| Since horizontal plane is parallelogram, floor plans & ohter plans must be redrawn @ 30 degree angle |
|
|
Term
| How is the 3rd dimension shown on isometric drawing? |
|
Definition
| BY extending points vertically |
|
|
Term
| How are diagonal lines drawn on isometric drawing? |
|
Definition
| by projecting endpoints from the basic 3D grid & connecting them |
|
|
Term
| What can isometric drawings be drawn to show? |
|
Definition
| buildings, interior rms,s details, millwork, furn, & any other object |
|
|
Term
| How can complex details be shown with isometric drawings? |
|
Definition
| by dwg section in one plane @ then extending rest of object w/ lines isometrically perpendicular to sec cut |
|
|
Term
|
Definition
| 2 of the principal axes are equally foreshortened |
|
|
Term
|
Definition
| all 3 of principal axes are foreshortened |
|
|
Term
| Short cut to true isometric projection should have foreshortened lines in 3 principal axes |
|
Definition
| Scale lines equally @ true size |
|
|
Term
| Shortcut for true diametric projection, angles and foreshortened lengths are complex to construct exactly |
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Definition
| for convenience a given angle, such as 15 degrees, is used for 2 of the axes & 3rd is drawn vertically on paper |
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Term
| Vertical lines of asometric drawings are draw @ full sclaee, what about foreshortened axes? |
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Definition
| drawn @ arbitrary 3/4s actual scale |
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Definition
| A 3D view of an object where one plane of object is parallel to picture plane while 3rd axis is oblique to picture plane |
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Term
| What does an oblique drawing show? |
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Definition
| 1 plane of an object (2D) in true shape & scale w/ the 3rd dimension drawn as lines @ fixed angle to true plane |
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Term
| What is the advantage of an oblique drawing? |
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Definition
| an existing orthographic floor plan can be used as starting pt wo/any redrawing |
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Term
| How is an existing plan used to begin oblique drawing? |
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Definition
| Plan is tilted @ any desired angle. 3rd dimension is created by projecting vertical lines. |
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Term
| What happens if the 3rd dimension on an oblique drawing is scaled the same as true shape? |
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Definition
| the object looks distorted |
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Term
| What can be done to compensate for distortion of 3rd dimension of oblique drawing? |
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Definition
| 3rd dimension usually drawn @ ½ - ¾ scale of true plane |
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Term
| How are diagonal lines in nontrue plane dimension drawn in oblique drawing? |
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Definition
| by determining location of their endpoints through projection along one or more of the 3 main axes |
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Term
| How are interior views created on oblique drawings? |
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Definition
| by omitting top & 2 front sides of room or by selectively cutting away portion of enclosing planes to show what’s inside |
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Definition
| Give most accurate 2D representation of 3D world |
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Term
| Principle of convergence (perspective drawings): |
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Definition
| apparent diminishing size of objects as they get farther from eye. Also explains how parallel lines seem to look nonparallel & point to, or converge on, same imaginary spot in distance |
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Term
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Definition
| when point of view is perpendicular to one of the planes of the object. All vert lines drawn vert, & all lines perp to line of sight are drawn horz. Lines parallel to line of sight converge @ 1 vanishing pt used to create dwg |
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Term
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Definition
| created when the pt of view is @ normal eye level & is not perpendicular to any plane of the object |
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Term
| What has superseded the NRC rating? |
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Definition
| Sound absorption average - the average of the absorption coefficients for the 12 1/3octabe bands from 200-2500 Hz when tested in accordance w/ ASTM C423 |
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Definition
| uses fractions of an inch to represent feet & inches |
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Term
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Definition
| used when a project is planned & represented w/SI (metric units). Graduated in proportions such as 1:50, 1:10, & 1.5 , & indivual markngs are based on millimeter lengths |
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Definition
| indicates feet & fractions of a foot & uses scales such as 1"=40' or 1"=100'. Typically used by civil engineer |
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Term
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Definition
| a band of alternating light & dark portions, each of which represents a given length. When used, the measurement of scale is not dependent on having a scale instrument; the graphic scale changes size in the same proportion as the drawing when reproduced |
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Term
| Preprinted perspective grids: |
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Definition
| To shorten time required to produce persepctive dwgs These have horizon lines, vanishing points, & distances already marked off Sheet of paper is placed over grid & a dwg is skeched in. |
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Term
| After adjacencies & bubble diagrams have been produced, how can design dwgs progress? |
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Definition
| from rough block diagrams to design development dwgs to final construction dwgs |
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Definition
| very detailed & accurately represent furniture, detail, colors, & finishes. Most often used for a final, formal client presentation |
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Term
| Study models/working models: |
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Definition
| rough models used by the designer as an aid to understanding the 3-D aspects of the space & are constructed in a variety of ways, depending on the needs of the designer & the time & budget available |
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Term
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Definition
| full-size representations of a portion of a design. Can be made of small elements, such as furniture, or of an entire room. Good way to communicate to client how something will look that hasn't been built, such as custom-designed workstation or prototype for a hotel room |
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