8.1a PRINCIPLES OF CONSTRUCTION Flashcards

1
Q

A29 - What are 6 types of sound that can reach a listener? (2 types not shown below)

A
  1. Incident Sound (mirror)
    • reflects off of surfaces with low a (sound absorb)
    • to be effective surface area>wavelength
    • returns @ angle = incident angle
  2. Diffracted Sound
    • airborne sound waves bent by obstacle in path
  3. Airborne Sound
    • Travels directly from source to listener
  4. Attenuation
    • greater distance from source = lower amplitude as it spreads
  5. Echoes
    • reflected sound waves
    • loud & late enough to be considered distinct
    • occurs w parallel surfaces 60’(18m) apart
  6. Focusing
    • convergence of sound waves reflected from concave surface
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2
Q

A1 - 3 BROAD ASPECTS WHICH IMPACT WINDOW PERFORMANCE

A
  • PHYSICAL CHARACTERISTICS OF WINDOW ASSEMBLY (window as system of elements)
  • PHYSICAL INTERFACE w THE ENCLOSURE (component of build. envelope)
  • EFFECTS OF WINDOWS ON QUALITY OF INDOOR SPACE (part of indoor environment)
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3
Q

A02 - 8 MAJOR FUNCTIONS OF A WINDOW:

A
  1. • CONTROL HEAT FLOW
  2. • LIMIT SOUND TRANSMISSION
  3. • PREVENT AIR/RAIN LEAKAGE
  4. • TRANSMIT LIGHT wOUT GLARE
  5. • BRING IN FRESH AIR & BLOCK INSECTS
  6. • AIRTIGHT BUT EASY TO OPERATE
  7. • BRING IN SOLAR HEAT IN WINTER not SUMMER
  8. • BLOCK/REFLECT UNWANTED LIGHT & UV RAYS
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4
Q

A3 - FUNCTION OF CAP BEAD & HEEL BEAD. WHAT DO THESE COMPONENTS PREVENT?

A

CAP: KEEP RAIN OUT (flank window pane @ sash in & out)

HEEL: AIR TIGHTNESS (inside joint seal) *PREVENT AIR LEAKAGE

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5
Q

A4 - 3 WAYS TO MITIGATE CONDENSATION ON WINDOWS.

A
  • ADD AIR SPACE w PLASTIC OR GLASS
  • CIRCULATE WARM AIR TOWARDS GLASS
  • REMOVE OBSTRUCTIONS
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6
Q

A5 - 4 WAYS TO MITIGATE SOUND TRANSMISSION IN A WINDOW SYSTEM.

A
  • LARGE GLAZING GAPS
  • THICKER GLASS
  • SEPARATE FRAMES/SASHES (INT/EXT)
  • COMPLETELY AIRTIGHT (fixed often perform better than operable)
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7
Q

A6 - 3 TYPES OF STRENGTHENED GLASS + PROS / CONS

A

1 - FULLY TEMPERED (surfaces in compression & core in tension) + 3-5x more resistant to fail due to

  • bend
  • impact
  • heat - impact along edge will shatter sheet

2 - HEAT STRENGTHENED (lower level of surface compression compared to fully tempered, same process) + stronger than annealed glass & less susceptible to shatter due to edge impact

3 - LAMINATED (bonded together with intermediate layers of plastic) + holds together if broken + can be used for solar heat control, sound control, bullet-resistance, blast resistance - not stronger than regular annealed glass

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8
Q

A07 - List the 5 main forces of moisture transfer in a building envelope.

A
  1. KINETIC ENERGY OF RAIN (impact)
  2. SURFACE TENSION (drip edges)
    • water clings to horizontal(ish) surfaces
  3. CAPILLARY (gaps <5mm)
    • water drawn into permeable materials & small openings (cracks, joints & junctions)
  4. GRAVITY
    • moves rain down surface and into sloped openings (holes cracks flashing)
  5. AIR PRESSURE DIFFERENCE
    • rain driven in direction of lower pressure
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9
Q

A08 - Describe the 2 lines of defence in a rainscreen system.

A
  1. CLADDING
  2. a DRAINED CAVITY
    • intercept all water that passes cladding
    • dissipate water to exterior:
      • evaporation
      • drain via flashing

2.b or WATERPROOF MEMBRANE

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10
Q

A09 - A rainscreen should also be protected, what are 3 ways to do so?

A
  1. ROOF OVERHANGS
  2. CORNICES
  3. BALCONIES
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11
Q

A10 - What are the 4 ‘D’s of preventing rain pentration?

A
  1. deflection
  2. drainage
  3. drying
  4. durability
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12
Q

A11 - List & describe the 4 main strategies for preventing moisture infiltration.

A
  1. Integral Sills & Drip Edges on Flashings
    • typ. projection of 10mm beyond cladding
    • 25mm may be rqrd
  2. Drainage Holes in Permanent Cladding
    • needs to slowly dissipate/evap water
    • min. 10mm to prevent capillary bridging
  3. Sealants/ Gaskets reduce openings
  4. Joints:
    1. Locked Joints (open)
      • ​​manage gravity driven
      • rqr 10mm overlap
    2. Lapped Joints (closed)
      • ​​rqr 5mm gap btwn to prevent capillary action
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13
Q

A12 - What STC rating does NBC rqr for dwelling units?

A

STC 50

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14
Q

A13 - What has the greatest impact on controlling sound transmission in a wall assembly? What are the 2 main ways of acheiving this with a wall assembly.

A

Isolate GWB

  1. Staggered Studs
  2. Double Wall
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15
Q

A14 - List 4 ways to alter a wall assembly to impact sound transmission, other than isolation of GWB.

A
  1. Increase Mass
    • 2xGWB will increase STC by 10points!
  2. Add Sound Absorbing Material
    • will increase STC by 10pnts in a stag or double wall
  3. Increase Stud Spacing
    • 400mm-600mm spacing on stag or double wall will increase StC by 1or2 pnts
  4. Include Resilient Channels
    • good for load bearing studs
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16
Q

A15 - When looking to control sound transmission, what should not be done, as it has no impact on sound transmission.

A
  1. inc. gwb @ center or assembly (actually reduces cavity size)
  2. inc. batt insulation - not beneficial at all
17
Q

A16 Define these 4 terms:

  1. NOISE
  2. PITCH
  3. VOLUME
  4. FREQUENCY
A
  1. NOISE
    • Any unwanted sound
  2. PITCH
    • Wavelength of sound
  3. VOLUME
    • Amplitude of sound
  4. FREQUENCY
    • # cycles/second (hertz)
18
Q

A17 - Define these 5 terms:

  1. ATTENUATION
  2. ARTICULATION
  3. SOUND INTENSITY
  4. SOUND ABSORPTION
  5. SOUND REVERBERATION
A
  1. ATTENUATION
    • reduction of sound
  2. ARTICULATION INDEX
    • measure of speech intelligability
    • >.6 = good communication
      1. SOUND INTENSITY
    • dB
  3. SOUND ABSORPTION
    • ratio of sound absorbed by material
    • unit = sabins
  4. SOUND REVERBERATION
    • persistance of sound after source stopped producing
19
Q

A18 - Define these 3 measures of sound :

  1. NC
  2. NRC
  3. STC
A
  1. NC - Noise Criteria
    • ​specifies max. background noise in a given space
  2. NRC - Noise Reduction Coefficient
    • # rating system for ave. sound sbsoption coefficient of a material @ frequencies of 250/500/1000/2000 Hz
  3. STC - Sound Transmission Class
    • Rating system to determine effectiveness of construction cross sections to stop sound transmission.
20
Q

A19 - What is the typ. STC rating for :

  1. normal speech heard through a barrier
  2. loud speech heard through a barrier
  3. loud speech heard but not understood
  4. loud speech is faint through barrier
  5. loud sound other than speech heard through a barrier
A
  1. STC 25
  2. STC 30
  3. STC 35
  4. STC 42-45
  5. STC 46-50
21
Q

A20 - What is the Inverse Square Law?

A

sound intensity = inversely proportional to square of distance to source

22
Q

A21 - Decibles and hearing?

  1. What is the measure in dB of the threshold of human hearing
  2. What increment of dB is and is not noticeable?
A
  1. zero dB
    1. 1 dB is not noticeable
    2. 5 dB is noticeable
23
Q

A22 - In what range of Hz does human conversation occur?

A

125Hz - 8000Hz

24
Q

A23 What relationship does TL have to NR (noise reduction)?

A

NR = TL(db)

25
Q

A24 - What is the function of noise criteria curves?

What is the PNC (preffered noise criteria) for each of the following spaces:

  1. concert hall
  2. bedroom
  3. lobbies
  4. kitchens
A
  1. 12-20 dB (concert hall)
  2. 20-30 dB (bedroom/hospital/aptmt)
  3. 40-45 dB (lobbies/labs)
  4. 45-55 dB (kitchens/light maint. shops)
26
Q

A26 - What is the measure of material absorption and what values reflects absorptive/reflective materials

A

a = coefficient of absorption (ratio of intensity)

**NRC(noise reduction coefficient)

= ave a @ 250/500/1000/2000Hz.

<0.2 = REFLECTIVE

>0.2 = ABSORPTIVE

27
Q

A27 - What is sound absorption useful for in sound control? (4)

A
  1. prevent sound reflection
  2. reduce sound intensity within space
  3. improve speech privacy
  4. decrease/enhance reverberation
28
Q

A28 - Reverberation affects the intellgibility of speech & music. Since each space has it’s own ideal reverberation time, what is the general rule for small spaces vs. large ones.

A
  1. small space = shorter reverb time
  2. large space = greater reverb time

examples:

  • 1.5-1.8s = auditorium
  • 0.6-0.8s = elem. classroom
  • 0.3-0.6s = office/small room for speech
29
Q

A29 - What are 4 ways to control mechanical noise?

A
  1. spec quiet equip
  2. line ducts
  3. use inertia blocks (heavy concrete) to min. vibration
  4. set upon resilient blocking to isolate from structure
30
Q

A30 - Define impact noise and the associated system commonly used to measure it.

A

Structure borne sound generated by impact:

  • footsteps
  • moving furniture

​Impact Insulation Class (IIC)

  • single # rating prevention of transmission of impact noise in ceiling/floor construction
  • higher IIC = lower sound transmission
31
Q

A31 - How can Impact Noise be improved? (3)

A
  1. carpet /rsf install
  2. suspended ceilings
  3. conc. slab floated on fibreboard laid on struct. slab.
32
Q

33 - What is the primary purpose of thermal insulation?

A

Control the flow of heat through an exterior assembly.

33
Q

32 - List the 4 most common types of insulation and their r-value per inch of thickness

A

Batt

= 3.3 (same fiberglass or rock wool)

Rigid board

= 2.5 (cellular glass)

= 3.6 - 7.2 (the various polys - polyisocyanurate highest)

Foamed in Place

= 6.2 (polyuerethane)

Loose fill

= 2.1 -3.7 (vermiculite to cellulose)

34
Q

34 - The steady state method of measuring thermal resistance of a construction assembly is useful, but these 4 factor also influence heat/loss gain:

A
  1. Surface colour / reflectivity
  2. Mass (time lag)
  3. Orientation (solar /wind)
  4. Latent Heat (occ. etc)
35
Q

35 - As a point of reference, know the typical R value of single and double glazing (w 5mm air space).

A

*APPROX DOUBLE

single R = .88

double R = 1.61