Green Building Systems exam 1
thermal barrier
(insulation) a boundary to heat flow this and air barrier must be complete and in contact with each other spray foam insulation works as both
the amount of water vapor that diffuses through a building is affected by the following factors:
1. chemical composition of building materials 2. thickness of building materials 3. absolute humidity on each side of the building assembly
Environmentally sensitive lands
1. land within the 100 year floodplain as defined by federal emergency management Agency 2. land that is specifically identified as habitat for any species on federal or state threatened or endangered lists 3. land within 100 feet of any body of water 4. areas identified as of special concert by state or local jurisdiction 5. land that was public parkland 6. land identified by state natural resources conservation services soil surveys to contain "prime soils" "unique soils" "soils of state significance"
BTU
british thermal units, heat. the amount of heat required to raise one pound of water one degree F
grayfield development
previously developed and underutilized real estate assets or land
brownfield
previously developed sites contaminated by hazardous waste or pollution that require environmental remediation prior to reuse.
pre plumbing
process of installing plumbing distribution systems during construction to meet future technology need
R-value
quantitative measure of the resistance to heat flow or conductivity states how much heat transmits through 1 square foot of surface in one hour with a 1 degree F difference between opposite surfaces (?) R value = btu/hr/oF/ft^2 R values can be added together to get a total R value insulation high R value
infill development
sites surrounded by existing or planned development immediately adjacent to the property boundaries
greenfield development
sites that are previously undeveloped, forest or farmland, should be avoided
edge development
sites with 25 percent or more of the property boundary adjacent to existing development.
grain
small unit of weight, one pound is 7000 grains.
best management practices (BMP)
strategies for keeping soil and other pollutants out of streams and lakes, BMPs are designed to protect water quality and prevent new pollution
sun tempered design
strategy in which the house and most of the glazing are oriented toward the south. passive solar design.
solar orientation
the cardinal direction in which the home and its glazing faces placing a house with a large wall of unshaded windows facing west will significantly increase the cooling load, requiring a larger HVAC system than if the house had been designed to reduce or shade those windows. can save money and energy
convective loop
the continuous circulation of air (or another liquid) in an enclosed space as it is heated and cooled
stack effect
the draft established in a building from air infiltrating low and exfiltrating high problem: in summer, the stack effect can actually reverse as hot attic air enters the home and forces relatively cool, air conditioned air out at the bottom
stormwater
the flow of water that results from precipitation following rainfall or as a result of snowmelt. water accumulates debris, chemicals, sediment, automotive fluids, or other pollutants before its discharged into streams and other rivers.
relative humidity (RH)
the percentage of the maximum moisture that the air can hold at a specific temperature recommended RH levels for indoor air quality and health range from 40-60%
passive solar design
the practice of designing a home to utilize the suns energy for heating and cooling
air sealing
the process of reducing air leakage into and out of a home typically accomplished by applying some combination of caulk, spray foam, weather stripping and other air IMPERMEABLE materials
perm rating
the rate of water vapor passage through a material under fixed condition
building envelope (thermal envelope)
the separation between the interior and the exterior environments of a building, consisting of an air barrier and thermal barrier that are continuous and in contact the dividing line between conditioned and unconditioned space in a house includes the exterior walls, ceilings, and floors, however many homes are built with conditioned or semi conditioned attics, basements, and crawl spaces where the roof and foundation walls and floor serve as the building envelope Consists of 2 components: thermal barrier, and air barrier
building science
the study of the interaction of building systems and components, occupants, and the surrounding environment, focusing on the flows of heat, air, and moisture
dew point
the temp at which vapor condenses into water droplets
dry bulb temperature
the temp of air indicated on an ordinary thermometer and does not account for the effects of humidity
wet-bulb temperature
the temperature recorded by either a sling thermometer or an aspirating psychrometer(takes into account everything)
convection
the transfer of heat through a fluid
glazing
the transparent part of a wall or door assembly that is usually made of glass south facing windows allow the winter sun's energy to penetrate further into the home, which provides heating and illumination benefits.
infiltration
the uncontrolled process byu which air or water flows through the building envelope into the home
conduction
transfer of heat from one solid to another through contact
permeance levels
vapor impermeable: .1 perm or less vapor semi-impermeable: between .1 and 1 perm vapor semi-permeable: between 1 and 10 perms vapor permeable: greater than 10 perms
integrated design
a collaborative method for designing buildings that emphasizes the development of a holistic design
Charrette
a design meeting consisting of all project stakeholders, held in the early parts of the design process and contains every discipline.
psychrometric chart
a graph showing the relationship between a particular sample of air's dew point temperature, dry bulb temperature, wet bulb temperature, humidity ratio, and relative humidity. the physical properties of moist air at a constant pressure.
Vapor diffusion retarder (VDR)
a material that reduces the rate at which water vapor can move through a material recommended on the exterior in warm humid climates and on the interior in cold climates, and not at all in mixed climates. AC with cold areas can cause condensation and create mold and problems
heating degree day HDD
a measure of how cold a location is over a period of time relative to a base temp, most commonly specified as 65 degrees
cooling degree day CDD
a measure of how warm a location is over a period of time relative to a base temp, most commonly specified as 65 degrees
slope disturbance
a process of destabilizing a slope through grading and site development
air barrier
a protective, air-resistant material that controls air leakage into and out of the building envelope made up of drywall, hardboard panels, foam board, and house wrap, all of which must be installed using sealants, tape, and caulk at joints between panels or sheets and around gaps at windows, doors, and other openings
low emissivity (low E)
a surface that radiates, or emits, low levels of radiant energy
exfiltration
air flow outward through a wall, building envelope, window, or other material
ERV/HRV
energy recovery ventilators or heat recovery ventilators, very efficient heat exchanger.
radiation
heat energy transferred through the air
spot ventilation
in bathrooms or kitchen fans
pre wiring `
is the process of installing electric wiring during construction to meet future technology demands.
energy
measurable quantity of heat, work, or lighT
whole house ventilation
mechanical ventilation. air handler and duct system, a separate fan and duct system, or a combination of the 2.