Site Analysis Flashcards
What is the formula to calculate slope?
G=d/L x 100%
G= slope of land (%) d= vertical distance between contours (ft) L= horizontal distance between contours (ft)
List 3 things solar orientation can influence on site planning
- Orientation of building to control solar heat gain/loss
- Location of outdoor spaces / activities
- Location of building entries (best on south bc sun will melt snow/ice)
When is the sun the lowest in the N hemisphere?
Dec 21 winter solstice
When is the sun the highest in the N hemisphere
June 21 (summer solstice)
Solar altitude
Angle above horizon
Azimuth
Angle of sun N/S of an E/W line
What orientation is best for a bldg in the N hemisphere?
Facing south. Just east of south (5°-25° east of south is best to maximize heat gain in winter and minimize heat gain in summer)
What is more effective for passive solar heating in winter - window overhangs or vertical baffles?
Baffles because the sun is lower in the morning/afternoon
List the 4 climate regions of N America
- Cool (Canada, N US, Rocky mountains)
- Temperate (middle US, NW US, NE US)
- Hot humid (SE US)
- Hot arid (SW US)
List some cold climate design strategies
- goal is to minimize exposed surface area to reduce heat loss & minimize northern exposure
- air locks at entries
- landscaping to block winter winds
- mech & active solar heating
- large windows facing south, small windows east/west
- dark materials for building exterior
- use interior materials with high thermal mass
List some design strategies for temperate climates
- minimize northern exposure, maximize southern exposure
- shade southern exposure with deciduous trees
- buildings best oriented with long direction along E-W axis
- active & passive solar heating
List some design strategies for hot-humid climates
- maximize natural ventilation (narrow floor plans with cross-ventilation, porches, etc.)
- shading
- use building materials with minimal thermal mass
- light color materials for building exterior
List some design strategies for hot-arid climates
-use materials with high thermal mass
-pools, roof ponds (for 1-2 story buildings)
-minimize opening sizes
Light color building materials on exterior
List 3 types of alternate energy systems
- Passive Solar Heating
- Natural Cooling
- Active Solar
Passive Solar Cooling
Utilizes shading, natural ventilation, radiative, evaporative, ground coupling methods
Radiative Cooling
Use thermal mass to store heat during day, release heat at night.
Type of passive cooling method
Ground Coupling
Use stable coolness of earth to cool building, typically by using ground source heat pump
Type of passive cooling method
What are other ways to implement natural cooling on a site?
- trees (shade)
- fixed shading devices (horizontal on south facade, vertical on north)
- use light colored / reflective materials
- limit use of paving
Passive Solar Heating Strategies
- orient long axis of building on E/W axis
- plant deciduous trees along E & W facades
List the 4 types of topography depicted by contour lines
- Ridge
- Valley
- Concave slope
- Convex slope
Ridge
Contour lines point in direction of downslope
Valley / Swale
Contour lines point in direction of upslope
Concave Slope
Closely spaced contour lines near top of slope
Convex Slope
Closely spaced lines at bottom of slope
With a sloping site, how is a building best oriented?
Parallel to direction of contours, to minimize cost of excavation & fill
What must new contour lines match up with?
Existing property line
Contour Line
Show elevation of land in plan view, used for slope analysis
Contour interval
Difference in elevation between contour lines
Slope
Represented as percentage, each 1% being 1 ft of vertical rise for every 100ft of horizontal distance
What % slopes are usable or all types of intense activities & easy to build on?
0%-4% slopes
What % slopes are suitable for outdoor activity, & can be built on without much difficulty?
4%-10% slopes
What % slopes are difficult to climb on/use for outdoor activity, & are difficult & expensive to build on?
> 10% slopes
What % slopes are very steep and subject to erosion?
> 25% slopes
Water Table
Underground level below which the soil is saturated with water. Generally follows slope of grade above
Runoff coefficient
Fraction of total precipitation not absorbed into ground
What things can increase runoff coefficient?
Roof runoff, runoff from roads, parking lots
Silt Fence
Temp. Fencing designed to allow water to pass through while filtering out sediment, and allowing sediment to settle.
Placed along the perimeter(s) where drainage would occur.
Helps to manage runoff during construction by installing before excavation.
How is soil classified?
By grain size and if it’s organic / non-organic
What 4 types of soil are there?
- Sand
- Gravel
- Silt
- Clay
Gravel
> 2 mm in diameter
Good for construction loads, drainage, sewage drain fields
Bad for landscaping
Sand
0.05 mm-2 mm in diameter
Good for construction loads, drainage, sewage drain fields
Bad for landscaping
Silt
0.002 mm-0.05 mm in diameter
Stable when dry, unstable when wet
Foundations & road basins must extend below silt
Clay
< .002 mm in diameter
Smooth and floury when dry, plastic & sticky when wet
Expands when wet, subject to slippage
Bad for foundations unless it can be kept dry
Bad for drainage
What kind of site is best for building (& least expensive for foundations)?
One with sand, gravel, and bedrock
What 9 things must the architect analyze during site analysis?
- Soil type
- Moisture content
- Depth of topsoil
- Depth to water table
- Depth to bedrock
- Drainage characteristics
- Susceptibility to compaction
- Soil fertility
- Rock outcropping DDS
Brownfield
Site whose expansion, redevelopment, or reuse may be complicated by presence or potential presence of hazardous substance, pollutant,or contaminant
-EPA provides funding for redevelopment
