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Air
Changes per Hour (ACH)
An expression of ventilation rates - the number of times in an hour
that a home's entire air volume is exchanged with outside air.
Air
barrier Meets ASTM E283 A layer of material resistant to air
flow usually in the form of polyolefin (i.e. Typar, Tyvek, and other
house wraps). A material which is applied in conjunction with a building
component (such as a wall, ceiling or sill plate) to prevent the movement
of air through that component.
Air barrier system The assembly of components used
in building construction to create a plane of air tightness throughout
the building envelope and to control air leakage.
Blower Door Diagnostic equipment consisting
of a calibrated fan, removable panel and gauges, used to measure and
locate air leaks.
Blowing agent A gas or a substance capable of producing
a refrigerant gas used in making foamed materials.
Btu British Thermal Unit - The amount of energy that is required to
raise 1 lb. of water up 1° F
Btu/h A rate of energy transfer - can be expressed
as Btu’s/hour
Building Envelope The external
elements walls, floor, ceiling, roof, windows and doors of a building
that encloses conditioned space; the building shell.
Capillary Action, Capillarity The movement
of liquid within a material against gravity as a result of surface tension.
CFC (Chlorofluorocarbon) Any of various halo carbon
compounds consisting of carbon, hydrogen, chlorine, and fluorine, once
used widely as aerosol propellants and refrigerants. Chlorofluorocarbons
are believe to cause depletion of the atmospheric ozone layer.
Combustion efficiency A measure of useful heat extracted
from a fuel source by an operating heating appliance. For example a
furnace with a combustion efficiency of 60 percent converts 60 percent
of the fuels energy content into useful heat. The rest is lost as exhaust
gases.
Conduction Transmission of energy (heat /sound) through
a material or from one material to another by direct contact.
Materials with low rates of conductive heat transfer make good insulation.
Convection
Transmission of energy (heat /sound) from one place to another by movement
of a fluid such as air or water.
Density Determined by the weight expressed
in pounds of a cubic foot of spray foam.
Dew Point The temperature at which a vapor begins to
condense.
Diffusion The movement of water vapor from regions
of high relative humidity (RH) toward regions of lower RH driven by
a higher to lower temperature differential.
Exfiltration Uncontrolled leakage of
conditioned air from inside the home to the outside.
Flame
Retardant A substance, which is added to a polymer formulation
to reduce or retard the tendency to burn.
Flame Retarded (Adj.) The property of a material to
which flame-retardant has been added.
Flame Spread Standard test for determining relative
combustibility. The flame spread of a tested material is rated relative
to red oak (flame spread = 100).
Flammability Relative ability of a material to support
combustion as expressed by its flash point.
Formaldehyde a colorless pungent irritating carcinogen
used chiefly in aqueous solution as a disinfectant and preservative
and in chemical synthesis
Heat loss Heat that is lost from a
building through air leakage, conduction and radiation. To maintain
a steady interior temperature, heat losses must be offset by a combination
of heat gains and heat contributed by a heating system.
Heat recovery ventilation system A mechanical ventilation
system that recovers energy from exhausted indoor air and transfers
it to incoming air. This system usually incorporates an air-to-air heat
exchanger which transfers the heat from exhaust air to the incoming
air or vice versa.
HCFC (Hydro chlorofluorocarbons) are compounds containing carbon,
hydrogen, chlorine and fluorine. They have shorter atmospheric lifetimes
than CFC's and deliver less reactive chlorine to the stratosphere where
the ''ozone layer'' is found.
HFA Propellant, usually hydrofluoroalkane-134a, used
in chlorofluorocarbon-free (CFC-free) aerosol delivery systems.
HFC (hydro fluorocarbon) HFC's have replaced ozone-depleting
chlorofluorocarbons (CFC's) in many applications but are
powerful greenhouse gases, with 100-year global warming potential of
between 140 and 11,700.
Humidistat A humidity sensitive control device that
signals the ventilation system to operate if the humidity goes above
a preset limit.
Hydrophobic Having no affinity for water; not compatible
with water. ''Water fearing''
Infiltration
Uncontrolled leakage of air into a building through cracks around doors,
windows, electrical outlets and at structural joints.
Insulation Materials with low thermal conductivity
characteristics that are used to slow the transfer of heat.
Isocyanate (MDI (diphenyl methane diisocyanate)) One
of a group of neutral derivatives of primary amines (R-N=C=O) groups.
An essential component (A) of spray foam chemistry.
Kilowatt-hour (kWh) Standard unit for
measuring electrical energy consumption-kilowatts per hour.
Material Safety Data Sheet (MSDS) A
standard formatted information sheet, prepared by a material manufacturer,
describing the potential hazards, physical properties, and procedures
for safe use of a material.
Mold Fungal growths often resulting in deterioration
of organic materials, especially under damp conditions.
Mycotoxin Any poisonous substance produced by a fungus.
Organic Compounds containing carbon.
Over spray ( 1) Airborne spray loss of polyurethane
foam. (2) Undesirable depositions of airborne spray loss.
Perm A unit of water vapor transmission
defined as 1 grain of water vapor per square foot per hour per inch
of mercury pressure difference (1 inch mercury = 0.49 psi). Metric unit
of measure is ng/m2 s Pa. 1 perm = 55 ng/m2 s Pa
Permeability The time rate of water vapor transmission
through unit area of a material of unit thickness induced by unit vapor
pressure difference between two specific surfaces, under specified temperature
and humidity conditions.
pH A measure of acidity/alkalinity of aqueous mixtures.
A measure of pH 7 is neutral, lower is more acidic, higher is more alkaline.
PSI Pounds per square inch
Radiation Transfer of energy (heat/sound) from one object to another
through an intermediate space. Only the object receiving the radiation,
not the space is heated. The heat is in the form of low frequency, infrared,
invisible, light energy, transferring from a ''warm'' object to a ''cold''
object. It is known as the 'black body effect.
Relative Humidity The ratio expressed
as a percentage of the amount of moisture air actually contains to the
maximum amount it could contain at that temperature.
R A unit of measurement of resistance to heat flow
in hr. ft2 ° F/BTU .in.
R-value
A material's ability to resist heat flow is measured by its R-value.
The higher the R-value the higher the insulating value of the material.
RSI
A unit of measurement of resistance to heat flow in m2 ° C/W per
25 mm. R = 0.176 RSI
Resin Component B in spray foam chemistry. This component
is mixed with the A component to form The Icynene Insulation System®
Retrofit The modification of an existing building or facility
to include new systems or components.
Standard Testing Laboratory test methodology for determining relative
properties of materials at specific conditions.
Rim Joist The rim joist of a floor
between heated spaces is a major leakage site and one that can be difficult
to seal well.
Thermostat
Temperature sensitive control device that signals a heating or cooling
system to operate if the temperature in the building reaches a preset
limit.
Thermal Barrier A material applied over Icynene® Insulation
designed to slow the temperature rise of the foam during a fire situation
and delay its involvement in the fire.
Thermal Bridge A thermally conductive
material which penetrates or bypasses an insulation system; such as
a metal fastener or stud.
Thermal Resistance (R) An index of a material's resistance
to heat flow. See R and RSI.
Thermal Shock A building materials reaction to rapid
changes in temperature.
Thermography A building energy diagnostic technique
using an infrared camera for locating areas of temperature differential
in a building.
U-Value Overall thermal conductance. U value
is equal to the inverse of the sum of the R-values in a system (U =
1 /R total).
Vapor Diffusion Retarder/Barrier A
layer of moisture resistant material usually which controls moisture
diffusion (defined as less than 1 perm) to prevent moisture build up
in the walls.
Viscosity The thickness or resistance to flow of a
liquid. Viscosity generally decreases as temperature increases; application
temperatures of spray foam components are specified in part, to control
viscosity at the spray gun.
Volatile Organic Compounds (VOC) Any compound containing
carbon and hydrogen or containing carbon and hydrogen in
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