Chapter 9

contour interval

is the difference in elevation between adjacent contour lines. will vary depending on the steepness of the slope, the scale of the map, and the amount of detail required.

soil

is the pulverized upper layer of the earth, formed by the erosion of rocks and plant remains and modified by living plants and organisms. soil is classified according to grain size and as either organic or inorganic: 1. gravel- particles over 2mm in diameter 2. sand- particles from 0.05-0.2 mm in diameter, the finest grains just visible to the eye 3. silt- particles from 0.002-0.05 mm in diameter, the grains are invisible but can be felt as smooth. 4. clay- particles under 0.002 mm in diameter, smooth and floury when dry, plastic and sticky when wet

water table

is the underground level below which the soil is saturated with water. generally, the water table follows the slope of the grade above, but it may vary slightly.

all soils are a combination of the preceding types, and any site analysis must include a subsurface investigation to determine the types of soil present as well as the water content.

1. gravels and sands are excellent for construction loads, drainage, and sewage drain fields, but they are unsuitable for landscaping 2. silt is stable when dry or damp but unstable when wet. it swells and heaves when frozen and compresses under load. 3. clay expands when wet and is subject to slippage. it is poor for foundations unless it can be kept dry. it is also poor for landscaping and unsuitable for sewage drain fields or other types of drainage because it retains water and drains slowly.

active solar

1. be aware that active solar collectors on a building can make a significant adverse visual statement unless they are placed on sloped roofs or are concealed with parapets. 2. position solar collectors so that they are not shaded by adjacent buildings and trees. if the collectors are to be mounted on the building, this may dictate the building's location. 3. position solar collectors so that they do not reflect sunlight onto other buildings or occupied areas nearby.

US Public Land Survey System (PLSS)

1. boundaries of site 2. PLSS starts with a set of east-west lines called parallels that follow the latitude lines of the earth with north-south lines called meridians 2. principal meridians and base lines-serve as the basis for the grid layout 3. other meridians called guide meridians and other parallels are called standard parallels. 4. the parallels and meridians are 24 miles apart, and the squares they form are called checks. 5. each 24 mi square is divided into 16 townships, each 6 mi on a side. the townships are referred to by a number referenced to a principal meridian and base line. the row of townships running east and west is referred to as a township, and the row of townships running north and south is referred to as a range. 6. each township is then further divided into 36 sections, each section being a one-mile square. these are numbered from 1-36, starting in the northeast section and moving east to west, dropping down to the next row south and moving west to east.

cold climates

1. buildings should ideally minimize the expose surface area to reduce heat loss. 2. suggests buildings with cubical shapes and those built partially underground 3. northern exposure should be minimized, as should door and window openings on the north side of the building. 4. entries should have air locks, and landscaping and building design should block winter winds. 5. mechanical heating and active solar heating are needed. 6. use compact forms with the smallest surface area possible relative to the volume 7. use large windows facing south, small windows facing east and west, and minimal or no windows facing north. 8. use interior materials that have high thermal mass 9. include summer shading for glazed areas 10. use dark or medium-dark colors for the building exterior.

the 4 broad climatic regions in the United States:

1. cool- includes all of Canada, the northern part of the middle of the US, and the mountainous regions of Wyoming and Colorado 2. temperate- most of the middle latitudes of the US, includes the northwest and northeast areas of the country. 3. hot-humid- includes the south eastern parts of the country 4. hot arid- stretches from Southern California across the desert southwest to portions of southern Texas

temperate climates

1. heat loss in the winter can be significant, so northern exposure should be minimized and winter winds should be blocked to reduce heat loss. 2. solar heat gain is desirable in the winter, so buildings should be oriented to maximize southern exposure. 3. same south facing sides of buildings should be shaded with deciduous trees and mechanical devices like awnings to protect from unwanted heat gain in summer. 4. to mitigate the effects of daytime heating, it is best to provide nighttime ventilation for the exhaust of hot air. 5. plan rectangular buildings with the long direction generally along the east-west axis and facing slightly to the east. 6. provide shade in the summer, and allow the sun to fall on glazing and the building in the winter 7. use south-facing openings to capture winter sunlight. 8. plan for the cooling effects of wind in the summer, block the wind in the winter 9. use medium colors for the building exterior

photovoltaics

1. if PVs are feasible for a building project, large surfaces may be needed for mounting. using large, flat roofs or sloped surfaces will optimize 2. pvs can be integrated with other building materials such as glass and roofing shingles. this technology is known as facade-integrated photovoltaics or building integrated PVs.

natural cooling

1. passive solar cooling utilizes the concepts of shading, natural ventilation, radiative cooling (use thermal mass to store heat during the day and release heat to the outside at night), evaporative cooling, and ground coupling (use the stable coolness of the earth to cool a building, typically by using a ground-source heat pump). 2. use trees and other landscaping to shade windows and other surfaces, unless direct solar radiation is needed for daylighting or passive or active solar heating. 3. to avoid excessive heat gain, use fixed shading devices. typically horizontal elements when used on the south side of a building, and vertical elements when used on the east and west sides. 4. a building can be made self-shading by designed it to be wider at the upper stories than at ground level. 5. minimize glazed areas on the east and west facades 6. use water elements and wind for evaporative cooling 7. use light colored or reflective materials to minimize radiant heat gains 8. avoid heat buildup around the structure by limiting the use of paving. use a pervious paving material that supports vehicles but allows grass or other vegetation to grow through. provide trees to shade the paving during hot summer months 9. locate the building on the site so as to take advantage of prevailing winds and natural ventilation strategies. courtyards may also be used.

alternative energy systems and methods can affect the overall project concept

1. passive solar heating- orient the long axis of the building in the east-west direction so that southern collection surfaces face within approx. 15 degrees of true south. should be integrated with daylighting design. both of these strategies will result in a building that is long and relatively narrow. a. if thermal mass is used, it may be featured as a design element b. plant deciduous trees to let sunlight fall on windows in winter and shade windows in summer.

hot-arid climates

1. shading from direct sunlight is needed. 2. use materials with high thermal mass; the heat stored during the day will be released at night 3. the same thermal mass then cools at night for daytime comfort. night ventilation is very useful for removing heat built up during the day. 4. pools can reduce local air temperature through evaporation. roof ponds for 1-2 story buildings provide both evaporative cooling and high thermal mass. 5. use compact forms with the smallest surface area possible relative to the volume. 6. minimize opening sizes 7. provide shade for openings 8. use light colors for the building exterior

hot-humid climates

1. should be planned to maximize the amount of natural ventilation by using narrow floor plans with cross ventilation, large, open windows, porches, and breezeways 2. shading is needed, either with vegetation or with double roofs 3. building materials should minimize thermal mass, so that the building does not store up heat during the day and release it at night. 4. provide shade for all openings. 5. maximize natural ventilation with large openings, high ceilings, and cross ventilation 6. use light colors for the building exterior

as a project moves into the schematic design phase, an architect should analyze:

1. solar orientation 2. design strategies for climatic regions 3. alternative energy systems

Solar orientation influences three aspects of site planning:

1. the orientation of the building to control solar heat gain and heat loss 2. the location of outdoor spaces and activities 3. the location of building entries

an appendix in ANSI/ASHRAE/IESNA 90.1 gives a county-by-county listing of each zone in the United States as well as details about the climate zones of other countries

8 climate zones are identified by this map, including 4 sub zones of moist, dry, marine, and warm-humid. the 8 zones are number and listed by name. although the architect should determine what climatic zone is applicable and follow code regulated guidelines, the 4 general climatic regions are useful as basis for preliminary design.

topography

describes the surface features of land. commonly used in land planning and architectural site development, a topographic map shows the slope and contour of the land as well as other natural and artificial features.

the orientation of a building (the direction its length faces) has a profound effect on energy gains and losses and on the comfort of its users

for most locations in the northern hemisphere, the best overall orientation for a building is with its principal facade facing south or slightly east or west of south. an orientation from 5-25 degrees east of south, depending on the climatic region, is considered an ideal balance between maximizing heat gains in winter and minimizing heat gains on the east and west facades in summer.

slope formula

g= d/L x 100% d= vertical distance (use contour intervals) L= length between two points

solar orientation can also affect the placement of building entries.

in cold climates, entries are best placed on the south side, where direct sun can melt ice and snow in the winter.

window overhangs can be used to shade windows in summer while letting the sun strike windows in winter for passive solar heating.

on east and west facades, however, vertical sun baffles are more effective than overhangs, because the summer sun is lower in the morning and afternoon, when it strikes the windows on these sides.

contour lines

shows the elevations of the land in a plan view and are used to make a slope analysis to determine the sustainability of the land for various uses.

existing contours can be divided into general categories according to their potential for various uses.

slopes from 0-4%: usable for all types of intense activity and are easy to build on. slopes from 4-10%: suitable for informal movement and outdoor activity and can also be built on without much difficulty. slopes over 10%: difficult to climb or use for outdoor activity and are more difficult and expensive to build on. depending on the soil, very steep slopes, over 25% are subject to erosion and become more expensive to build on.

silt fence

temporary fence designed to allow water to pass through while filtering out sediment and allowing the sediment to settle.

runoff coeffecient

the fraction of total precipitation that is not absorbed into the ground. if the runoff is greater than the capacity of the natural or artificial drainage from the site, holding ponds must be constructed to temporarily collect site runoff and release it at a controlled rate.

metes and bonds description

the long description starts at one point of the property and gives the length and direction of each line around the property's boundary, returning to the starting point at the end.

the orientation of the building in regard to winds is a closely related issue.

the orientation of a building and the locations of windows, plazas, and other elements can either take advantage of cooling breezes in hot, humid climates during the summer or shield the building and occupants from cold winds in the winter. in most temperate climates, prevailing wind patterns change with the seasons, so a wind analysis is needed to determine the direction of summer and winter winds.