8.1a PRINCIPLES OF CONSTRUCTION Flashcards
A29 - What are 6 types of sound that can reach a listener? (2 types not shown below)
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Incident Sound (mirror)
- reflects off of surfaces with low a (sound absorb)
- to be effective surface area>wavelength
- returns @ angle = incident angle
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Diffracted Sound
- airborne sound waves bent by obstacle in path
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Airborne Sound
- Travels directly from source to listener
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Attenuation
- greater distance from source = lower amplitude as it spreads
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Echoes
- reflected sound waves
- loud & late enough to be considered distinct
- occurs w parallel surfaces 60’(18m) apart
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Focusing
- convergence of sound waves reflected from concave surface
A1 - 3 BROAD ASPECTS WHICH IMPACT WINDOW PERFORMANCE
- 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)
A02 - 8 MAJOR FUNCTIONS OF A WINDOW:
- • CONTROL HEAT FLOW
- • LIMIT SOUND TRANSMISSION
- • PREVENT AIR/RAIN LEAKAGE
- • TRANSMIT LIGHT wOUT GLARE
- • BRING IN FRESH AIR & BLOCK INSECTS
- • AIRTIGHT BUT EASY TO OPERATE
- • BRING IN SOLAR HEAT IN WINTER not SUMMER
- • BLOCK/REFLECT UNWANTED LIGHT & UV RAYS
A3 - FUNCTION OF CAP BEAD & HEEL BEAD. WHAT DO THESE COMPONENTS PREVENT?
CAP: KEEP RAIN OUT (flank window pane @ sash in & out)
HEEL: AIR TIGHTNESS (inside joint seal) *PREVENT AIR LEAKAGE
A4 - 3 WAYS TO MITIGATE CONDENSATION ON WINDOWS.
- ADD AIR SPACE w PLASTIC OR GLASS
- CIRCULATE WARM AIR TOWARDS GLASS
- REMOVE OBSTRUCTIONS
A5 - 4 WAYS TO MITIGATE SOUND TRANSMISSION IN A WINDOW SYSTEM.
- LARGE GLAZING GAPS
- THICKER GLASS
- SEPARATE FRAMES/SASHES (INT/EXT)
- COMPLETELY AIRTIGHT (fixed often perform better than operable)
A6 - 3 TYPES OF STRENGTHENED GLASS + PROS / CONS
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
A07 - List the 5 main forces of moisture transfer in a building envelope.
- KINETIC ENERGY OF RAIN (impact)
-
SURFACE TENSION (drip edges)
- water clings to horizontal(ish) surfaces
-
CAPILLARY (gaps <5mm)
- water drawn into permeable materials & small openings (cracks, joints & junctions)
-
GRAVITY
- moves rain down surface and into sloped openings (holes cracks flashing)
-
AIR PRESSURE DIFFERENCE
- rain driven in direction of lower pressure
A08 - Describe the 2 lines of defence in a rainscreen system.
- CLADDING
- a DRAINED CAVITY
- intercept all water that passes cladding
- dissipate water to exterior:
- evaporation
- drain via flashing
2.b or WATERPROOF MEMBRANE
A09 - A rainscreen should also be protected, what are 3 ways to do so?
- ROOF OVERHANGS
- CORNICES
- BALCONIES
A10 - What are the 4 ‘D’s of preventing rain pentration?
- deflection
- drainage
- drying
- durability
A11 - List & describe the 4 main strategies for preventing moisture infiltration.
-
Integral Sills & Drip Edges on Flashings
- typ. projection of 10mm beyond cladding
- 25mm may be rqrd
-
Drainage Holes in Permanent Cladding
- needs to slowly dissipate/evap water
- min. 10mm to prevent capillary bridging
- Sealants/ Gaskets reduce openings
- Joints:
-
Locked Joints (open)
- manage gravity driven
- rqr 10mm overlap
-
Lapped Joints (closed)
- rqr 5mm gap btwn to prevent capillary action
-
Locked Joints (open)
A12 - What STC rating does NBC rqr for dwelling units?
STC 50
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.
Isolate GWB
- Staggered Studs
- Double Wall
A14 - List 4 ways to alter a wall assembly to impact sound transmission, other than isolation of GWB.
-
Increase Mass
- 2xGWB will increase STC by 10points!
-
Add Sound Absorbing Material
- will increase STC by 10pnts in a stag or double wall
-
Increase Stud Spacing
- 400mm-600mm spacing on stag or double wall will increase StC by 1or2 pnts
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Include Resilient Channels
- good for load bearing studs