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Flashcards in Environmental Factors Deck (20):
1

GRAVEL

well-drained, bears loads
2mm or larger

2

SAND

well-drained; can serve as foundation if graded
0.5-2mm

3

SILT

stable when dry, swells when frozen
0.002-0.5mm

4

CLAY

to stiff when dry and too plastic when wet
0.002 mm or smaller

5

Human comfort
winter
summer
humidity

63-71 degrees
66-75 degrees
30-60% is tolerable
75% or more is uncomfortable

6

Wind speed
unnoticeable
pleasant
pleasant and noticeable
drafty
uncomfortable

unnoticeable: less than 50 feet/min.
pleasant: 50-100 ft/min.
pleasant and noticeable:100-200 ft/min.
drafty: 200-300 ft/min.
uncomfortable: over 300 ft/min.

7

U-factor

high: fast heat transmission
low: low heat transmission

8

R-value

inverse of U
high: high thermal resistance
low: low thermal resistance

9

8 areas most to least tolerant of development, according to Ian McHarg's Design With Nature

surface water
marsh
floodplain
aquifer recharge area
aquifer
steep slope
forests/woodland
flat land (except prime agricultural land)

10

100 YEAR FLOOD

flood that has a 1% chance of occurring in any given year

11

INFILTRATION BASIN

temporarily collects water and only releases by absorption into the earth; recharges groundwater

12

CATCH BASIN

temporarily collects water and dumps into storm sewer

13

BIOSWALE

grassy sloped ditch that filters storm runoff and directs away from impermeable areas. allows water to seep into ground and helps recharge aquifers

14

CISTERN

tank for collecting and storing water; often a rainwater harvest system for irrigation and non-potable uses

15

ALBEDO

measure of solar reflectance; 0 is flat black and 1 is mirror

16

angle of repose for:
loose, wet clay or silt
compact dry clay
wet sand
dry sand

loose, wet clay or silt: 30%
compact dry clay: 100%
wet sand: 80%
dry sand:65%

17

DESIGN FOR HOT ARID CLIMATE

minimize sun exposure and effects of wind
use small windows
optimize thermal mass for big temperature swing
cluster buildings to shade each other

18

DESIGN FOR HOT HUMID CLIMATE

minimize sun exposure and maximize natural ventilation
use lightweight construction to minimize radiant heat
space buildings far apart to allow breezes

19

DESIGN FOR TEMPERATE CLIMATE

maximize solar gain in winter and minimize in summer
maximize breezes in summer and minimize in winter
take advantage of daylighting opportunities

20

DESIGN FOR COLD CLIMATE

orient buildings and openings for maximum protection from cold winds
use small windows and compact shapes to minimize heat loss
use south-facing windows to maximize solar gain