Ballast: Chapter 12 - Site Work Design Development Flashcards
1
Q
Aboveground Drainage Systems
A
Pervious paving, sheet flow, gutters, ground swales, and channels
2
Q
Underground Drainage Systems
A
perforated drains and enclosed sewers
3
Q
What is the minimum drainage slope to facilitate sheet flow on a paved surface?
A
As little as 0.5% (6” per 100’) for smooth surfaces, but typically 1.5% (1.5’ per 100’) for rough paved surfaces
4
Q
What is the minimum drainage slope for underground piping?
A
0.3% (4” per 100’)
5
Q
Storm Drain
A
Collect water from roof downspouts, drain inlets, catch basins, and drain tiles surrounding the building foundation
6
Q
Drain Inlet
A
An opening in the ground that allows stormwater to run directly into the storm sewer
7
Q
Catch Basin
A
Underground reservoir that has a sump built in to collect and prevent debris from flowing into the storm sewer
8
Q
Runoff Coefficient
A
The fraction of water not absorbed by the site itself
9
Q
An n-year Storm
A
Inversely related to the probability of a storm of said value happening in a given year (100-year storm has 1% chance, 25-year storm has 4% chance)
10
Q
What n-year storm are drains commonly designed for?
A
A 25-year storm
11
Q
Holding Pond
A
Collects storm runoff and releases it into the sewer system at a controlled rate
12
Q
Which utility usually takes precedence in planning a site and why??
A
Sanitary and storm sewer because because they depend on gravity flow
13
Q
What is the minimum slope for a building sewer?
A
0.5% - 2.0% depending on the diameter. The narrower the diameter the greater the necessary slope.
2.5” dia. pipe: 0.25” per ft
3.0” - 6.0” dia. pipe: 0.125” per ft
>8.0” dia. pipe: 0.0625” per ft
14
Q
Minimum width for 1 and 2 way driveways?
A
12’ for 1 way; 24’ for 2 way
15
Q
Minimum distance between driveway entry and public intersection?
A
150’
16
Q
Minimum radius for cul-de-sac turnaround?
A
40’
17
Q
Suggested width for planting strip between movement lanes?
A
7’ with trees, 4’ with just grass
18
Q
Width of side parking lane?
A
8’
19
Q
Maximum slope of roadway?
A
15%, but 10% or less is preferable with transition slopes before and after the ramp of half the ramp’s slope; there should also be a level area between any slope and a sidewalk crossing for car to settle
20
Q
The high point in the center of the roadway with a gradual cross slope running to a gutter or drain?
A
The crown
21
Q
Minimum slope from crown of road to gutter or drain?
A
0.25” per ft
22
Q
Suggested height of gutter located on a road?
A
6”
23
Q
Minimum widths of sidewalks and main walks?
A
5’ and 6’ - 8’
24
Q
Maximum slopes for walks?
A
4% (0.5” per ft) cross slope
6% preferred elsewhere
8% absolute max (1” per ft; 1:12)
25
Max slope and length of ADA ramp?
1" per ft (1:12) and 30' without a landing
26
Required parking is determined by what document?
Zoning Ordinance
27
What is the standard size of a parking space (parking bay, parking stall, car stall)?
9' x 19' for a standard car and 7'-6" x 15' for a compact car (400 sq.ft. per car is used to approximate total area needed for a parking lot).
28
What angle of parking arrange is the most space efficient?
90 degrees (double loaded)
29
What angle of parking is easiest to navigate?
30 degrees
30
Minimum width of ADA van parking space with access aisle?
16' (8' space with 8' aisle or 11' space with 5' aisle)
31
In general how does a row of trees of a certain height affect the velocity of wind?
30% - 40% reduction at a distance about 5 times the height of the trees
32
Suggested slope in a parking area?
1.5% (18" per 100') to 5% (5' per 100')
2% or 3% are most common
33
What are the azimuth and altitude of the sun?
Azimuth is the compass orientation of the sun and the altitude is the apparent height of the sun measured at an angle from the horizon.
34
What are the 4 types of sun charts?
Rectilinear, Equidistant horizon projection, Gnomonic projection (sunpeg chart), and the Stereographic (fisheye) projection
35
Passive Solar Energy System
Collects, stores and distributes solar energy without the use of mechanical equipment
36
Direct Gain Systems
Collect heat through south-facing glass and then store this heat in high-mass materials such as concrete floors, masonry walls, tile, stone, and terrazzo. During the night, these materials slowly release the heat.
To make this work efficiently, glass area must be well insulated at night or low emissivity (low-e) glass.
37
Indirect gain Systems
Collect heat from air temperature or reflected light. During the night, these materials slowly release the heat.
This is 1/4 as effective as Direct Gain Systems.
38
Thermal Storage Wall
Part of a Direct Gain System, a wall is placed opposite a south-facing glass wall.
Most are vented, which allows cool air to circulate in the space between the glass and wall, become heated, and travel by convection up and over the wall and back into the space. Thermal storage walls can also be constructed of water containers as water is more effective at storing heat.
39
Trombe Wall
Part of a Direct Gain System, a wall is placed opposite a south-facing glass wall.
The wall is vented on the top and bottom, which allows cool air to circulate in the space between the glass and wall, become heated, and travel by convection up and over the wall and back into the space.
40
Phase Change Materials
Used to avoid the overheating and wide swings in temperature in concrete, masonry, and water.
Eutectic salts that change from solid to liquid at 70 degrees F are commonly used as they store regular heat as well as latent heat as they change state.
41
Greenhouse Design
Features a large glazed area on the south side of the building with a high thermal mass wall separating it from the rest of the structure. A rock bed or high thermal mass floor is built in the greenhouse.
While the greenhouse overheats and is subject to thermal loss at night, the warm air circulates into the rest of the space.
42
Roof Pond
Stores heat in large water-filled bags on the roof of a building. In winter during the day, the bags heat up. At night, insulation is moved over the roof pond and the bags release heat down into the building.
The same system can be used inversely (insulation down during the day) to cool a space.
43
Active Solar Design
Uses fans, pumps, ducts, and other mechanical equipment to collect, store, and distribute solar energy.
The most common example of an Active Solar Design System is a "passive system with active assist (using an accompanying system of ducts and fans to distribute heat).
44
What 3 components make up an Active Solar System?
A collector, storage device, and a distribution system.
45
What are the 2 types of Collectors used in Active Solar Systems?
Flat plate and focusing.
Flat plate includes networks of water pipes laid over a black surface. These pipes can be filled with water with antifreeze.
46
What are the 2 examples of Storage Devices used in Active Solar Systems?
Water for water systems and rock beds for air systems.
47
Geothermal Energy
Uses ground-source heat pumps (GSHP) to transfer heat between a space and the earth.
Water within plastic pipes can either transfer or absorb heat to/from the earth to cool or heat (respectively) a space.
48
Photovoltaics
Convert sunlight directly into electricity.
49
What are the 3 types of Photovoltaics?
Crystalline (most effective)
Polycrystalline (less expensive, but less effective than crystalline)
Thin Film (Amorphous) Cells (can be integrated into building surfaces, but least effective)
50
What is the ideal angle for photovoltaic orientation?
The angle should be the same as the latitude of the building.
For maximum energy generation in the winter, the tilt angle should be 10 to 15 degrees greater than the latitude.
51
What are 4 examples of alternative energy sources?
Direct/Indirect Solar, Wind, Geothermal, and Photovoltaics
52
What are 8 examples of passive design methods for energy efficiency during design development?
1. Building Orientation
2. Building Shape
3. Building Shading
4. Insulation and Weather Sealing
5. Earth Sheltering
6. Green or Cool Roofs
7. Glazing
8. Daylighting
53
What are the optimal orientation of the long facade of buildings in a cool climate? temperate climate? hot-arid climate? hot-humid climate?
15 degrees in general, but
Cool climate: 12 degrees East of South
Temperate climate: 17.5 degrees East of South
Hot-Arid climate: 25 degrees East of South
Hot-Humid climate: 5 degrees East of South
54
Building Orientation Considerations:
1. Buildings in Cold climates should have their entrances on the leeward side to avoid winter winds
2. Buildings in Temperate climates should have their entrances on the south side to take advantage of snow-melting heat
3. Buildings in Hot-Arid and Hot-Humid climates should be rotated to catch cooling breezes
55
Building Shape Considerations:
1. Closer to cubic is most efficient for energy use
| 2. Thin sections are best for natural ventilation and daylighting
56
What is the optimal building shape for an external load dominated (houses, apts, condos, warehouses) building in a cool climate?
Square or cube
57
What is the optimal building shape for an external load dominated (houses, apts, condos, warehouses) building in a temperate climate?
Rectangle with 1:1.5 or 1:2 proportions E/W facade length to N/S facade length
58
What is the optimal building shape for an external load dominated (houses, apts, condos, warehouses) building in a hot-arid climate?
Courtyard
59
What is the optimal building shape for an internal load dominated (offices, hospitals, retail stores, schools, labs) building in a cool climate?
Square, multistory
60
What is the optimal building shape for an internal load dominated (offices, hospitals, retail stores, schools, labs) building in a temparate climate?
Elongated rectangle, multistory
61
What is the optimal building shape for an internal load dominated (offices, hospitals, retail stores, schools, labs) building in a hot-arid climate?
Slightly elongated rectangle, multistory
62
What is the optimal building shape for an external load dominated (houses, apts, condos, warehouses) building in a hot-humic climate?
Rectangle with 1:3 or 1:4 proportions E/W facade length to N/S facade length
63
What is the optimal building shape for an internal load dominated (offices, hospitals, retail stores, schools, labs) building in a hot-humid climate?
Very elongated rectangle, multistory
64
What are the optimal sun shading techniques for the south-facing facade of a building? east/west-facing facades?
South-facing: Horizontal louvers or building overhang
| East or West-facing: Vertical louvers
65
What are 6 common insulation materials?
1. Fiberglass
2. Mineral wool
3. Polystyrene
4. Polyisocyanurate
5. Polyurethane
6. Cellulose
66
What are 5 common forms of insulation?
1. Loose fill
2. Batts
3. Rigid foam boards
4. Spray-on foam
5. Structural insulated panels
67
Wind, the Stack Effect, and mechanical systems of a building can cause what 2 problems that result in energy loss?
Infiltration and Exfiltration (air leakage)
68
What are the 2 type of air barrier?
1. Vapor-impermeable: helps reduce the transmission of water into a building to prevent mold
2. Vapor-permeable; housewrap for example
69
Permeance
How readily a material or membrane allows water vapor to pass through it.
Unit: 1 Perm = 1 grain water per hour/sq.ft./in mercury pressure difference
Vapor permeable: >5 Perms
70
What are the 4 advantages of Earth Sheltering for a building?
1. The Earth's temp is stable a few feet down
2. Protects the structure from winter winds/hail/tornados
3. Natural sound proofing
4. Less outdoor maintanence
71
What are the 3 methods of Earth sheltering?
1. Building aboveground and berming around the structure
2. Embedding into the side of a hill (with south facade facing out)
3. Completely underground with courtyard
72
What are the 9 advantages of a Green Roof?
1. Energy conservation
2. Reducing storm runoff
3. Absorbing carbon dioxide
4. Reducing ambient air temperatures
5. Filtering the air and binding dust particles
6. Reducing the heat island effect
7. Protecting roofing membranes from UV, temperature extremes, wind, and hail
8. Adding acoustical insulation
9. Adding aesthetic appeal
73
What are the 2 types of Green Roof?
1. Extensive (<6" of soil; can support meadow grasses, sedums, herbs, and perennials)
2. Intensive (usually >12" of soil; can support complex landscapes including trees and shrubs, ponds, fountains, etc.)
74
What are the 9 layer components of a Green Roof?
1. Plants*
2. Growing medium or soil*
3. Filter fabric
4. Drainage layer
5. Rainwater retention layer
6. Insulation*
7. Root barrier or concrete protective slab*
8. Waterproof membrane*
9. Structural deck*
* Extensive Roof components
75
Solar Heat Gain Coefficient (SHGC)
The amount of solar radiation that is transmitted through the entire window assembly, expressed as a fraction of the total amount that strikes it. Applies to the glass, frame, glass spacer, and other window coponents
76
Shading Coefficient (SC)
The ratio of the amount of solar radiation that passes through a piece of glass to the amount that would pass through a similar piece of unshaded, clear, double-strength 1/8" thick under the same conditions. This applies only to the glass. Mostly superseded by Solar Heat Gain Coefficient (SHGC)
77
What are the comparative U-values (Units: Btu/sq.ft./hr/degree F) of innovative types of glazing?
(U-Value represents "heat leakage" so lower value is superior)
These values are approximates:
1. 11 - Single pane of glass
0. 57 - Double/triple glazed with 0.25" air gaps
0. 52 - Double/triple glazed with 0.25" air gaps filled with argon or krypton
0. 36 - Double glazed with low-e coating and 0.25" argon-filled cavity
0. 28 - Double glazed with low-e coating and 0.5" argon-filled cavities
0. 15 - Triple glazed with 2 low-e coatings and 0.25" argon-filled cavities
78
Low-e Glass (Low-emissivity Glass)
Double glazing that includes a thin film or coating placed somewhere in the glazing cavity. This allows both visible and near-infrared radiation to me transmitted, but when objects in the room heat and emit long-wave radiation, it prevents the loss of heat.
79
Spectrally Selective Glazing
Transmits a high proportion of the visible solar spectrum while blocking up to 80% of the heat from the infrared portion of the spectrum. Used with a low-e coating, a double glazed window has a SHGC of about 0.25. Good for buildings with long cooling seasons, but need high interior light levels.
80
Super Windows!
Glazing units that combine 2 low-e coatings with gas filled cavities between 3 layers of glass. These units can gain for thermal energy than they loss over a 24 hour period in winter.
81
Switchable Glazings or Chromogenic Windows
Products that change their characteristics based on particular environmental conditions or through human intervention.
82
Electrochromic Glazing
Consists of a multilayered thin film, applied to glass, that can change between opaque and clear or change colors when a burst of low-voltage electrical current is applied. Once the change has occurred the voltage does not need to be maintained.
83
Photochromic Glazing
Darkens under the direct action of the sun (think transitions lenses). Cannot be controlled by user.
84
Thermochromic Glazing
Darkens in response to temperature. Cannot be controlled by user.
85
Transition-metal Hydride Electrochromics
Make it possible to have glazing material that changes from transparent to reflective.
86
Double Envelope System
The outer skin of a building consists of two glazed layers that are typically separated by 2'-3'. Some type of sun control (louvers, blinds, or shades) and either an active or passive ventilation system is incorporated into the space. The system may include devices to redirect sunlight into interior spaces.
The outer shell moderates the weather. The cavity can be heated if needed. It also can exhaust excess heat or direct it into heat exchangers to warm incoming air in cold weather.
87
How much of a commercial building's energy use is consumed by electric lighting and the cooling needed to offset the heat it generates?
30-40%
Daylighting seeks to offset this cost with window placement, reflective surfaces, and other design elements to drive natural light into a space.
88
Dynamic Buffer Zone System
Building a new envelope around an existing structure to control condensation as a byproduct of upgrading a building's HVAC system to higher humidity levels. The cavity is ventilated with dry, preheated air during winter months.
89
Daylighting Factor (DF)
The ratio of illuminance at a point on a horizontal plane indoors to the illuminance at a point on a horizontal plan outdoors and fully open to the sky, under overcast skies. Direct sunlight is excluded. DF is expressed as a percentage, but the % can be excluded (DF of 2% or DF of 2).
90
What are the suggested Daylighting Factors for ordinary visual tasks? difficult visual tasks?
DF is the ratio of illuminance at a point on a horizontal plane indoors to the illuminance at a point on a horizontal plan outdoors and fully open to the sky, under overcast skies.
1.5%, 4%
91
At what Daylighting Factor does glare and excess heat gain begin?
DF is the ratio of illuminance at a point on a horizontal plane indoors to the illuminance at a point on a horizontal plan outdoors and fully open to the sky, under overcast skies.
>5%
92
Name 7 variables that can effect daylighting:
1. Compass orientation of facade
2. Brightness of the sky (affected by solar altitude, cloud conditions, and time of day)
3. Area of glass
4. Height of the head of the glass
5. The transmittance of the glass
6. The reflectances of interior surfaces
7. Obstructions such as overhangs or trees
93
Daylighted Zone
The depth into a space from the facade that light travels based on the height of the window head.
A standard window has a Daylighted Zone with a depth of 1.5 times the height of the window head.
Adding a light shelf increases that to 2-2.5 times the height of the window head.
94
Light Shelf
A horizontal surface placed above eye level that reflects direct daylight onto the ceiling while shading the lower portions of the window and the interior of the room.
95
Top Lighting
The use of light pipes, skylights, roof monitors, saw-toothed roofs, or sloped glazing for daylighting.
96
For daylighting, what are the suggested reflectances of ceilings? walls? floors?
80% for ceilings, 50-70% for walls, 20-40% for floors.
97
Name 6 basic principles for designing outdoor sound barriers:
1. Solid barriers are better at blocking high-frequency noises than low
2. The barrier is best placed as possible to either the source or the receiver of the sound
3. If it is placed close to the source, the barrier should be 4X as the distance from the source to the barrier
4. The greater the height, the better
5. For blocking noise from a point source, a short barrier should be 4X as long as the distance from the barrier to the sound
6. A barrier should have a density of 5 lbm/sq.ft. and be solid (>5 lbm/sq.ft. of density does not significantly increase sound attenuation)
98
Name 7 methods for controlling site noise:
1. Maximize distance between the noise source and the receiver
2. Avoid hard surfaces near the source of noise
3. Avoid parallel hard surfaces
4. Plant evergreen trees and shrubs densely between the noise source and receiver
5. Control noise sources that are in or near the building
6. Make use of masking sounds (fountain, running water)
7. Design building features to block noise
99
What are the 4 levels of site security?
1. Perimeter protection
2. Access and parking
3. On-site security
4. Building envelope protection
100
Site Security: Perimeter Protection
A physical barrier that is the first line of defense of a building. Can be as simple as a fence or as serious as security check point to hold unauthorized vehicles at a standoff distance.
Other strategies include walls, elevation changes, bollards, dry moats, water features, landscaping, or hardened street furniture.
101
Site Security: Access and Parking
Strategies include limiting the number of access points, the use of card-controlled gates or guard stations, visual or camera surveillance, retractable bollards, sally ports (where there are 2 gates to prevent access by force or tailing another car).
Other strategies include adequately illuminating sensitive areas and clear signage.
102
Site Security: On-Site Security
Using hardened furniture (pools, planters, low walls, lighting poles, benches, etc.) to protect outdoor gathering places on site from outside attack.
Can also include provisions at building entries for queuing when entrance inspection is needed.
103
Site Security: Building Envelope Protection
Designing envelope materials to resist forced entry or damage from explosives.
Solid facade walls can be made attractive with texture, murals, step-backs, etc. or solid wall can be inside of a glass wall with a hallway space between.
Entrances and egresses should be easy to use and accessible in the case of an evacuation.
Site lighting and surveillance must be planned.
Secure access to HVAC can be designed to prevent biological attacks.
104
Neighborhood Context Considerations:
1. Scale, massing, and fenestration of adjacent buildings
2. Functional adjacencies (to transit, outdoor space, etc.)
3. Views
4. Symbolic adjacencies (major axis, monument, etc.)
105
Balance Point Temperature
The outdoor temperature at which a building transitions from a heating need to a cooling need
106
Daylight Anatomy (DA)
The percentage of an area that meets a minimum daylight illuminance level for a specified fraction of the operating hours per year (e.g. 30 lux for 50% of the time). One of the options for receiving LEED credits for daylighting
107
Effective Aperature
The product of visible light transmittance (VLT) and window-to-wall ratio (WWR)
108
Glazing Factor
A LEED-based number calculated by taking into account window area, floor area, a window geometry factor, light transmission, and a window height factor
109
Ground Light
Visible light from the sun and sky, reflected be exterior surfaces below the plane of the horizon
110
Net Metering
Requires a utility company to charge and pay the same rate for electricity so that excess on site energy can be sold back to the grid
111
Visible Light Transmittance (VLT)
The fraction of visible light that passes through a glazing material
112
Window-to-Wall Ratio (WWR)
The ratio of net glazing area in a room to the gross exterior wall area
