Air barrier 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.
Blowing agent A gas or a substance capable of producing a 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
BTUH A rate of energy transfer – can be expressed as BTUs/hour
Building Envelope The external elements walls, floor, ceiling, roof, windows and doors of a building that encloses conditioned space; the building shell.
CFC (Chloroflourocarbon) Any of various halocarbon compounds consisting of carbon, hydrogen, chlorine, and fluorine, once used widely as aerosol propellants and refrigerants. Chlorofluorocarbons are believed 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% converts 60% of the fuel’s 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.
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.
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.
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 (Hydrochlorofluorocarbons) are compounds containing carbon, hydrogen, chlorine and fluorine. They have shorter atmospheric lifetimes than CFCs and deliver less reactive chlorine to the stratosphere where the “ozone layer” is found.
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”
Insulation Materials with low thermal conductivity characteristics that are used to slow the transfer of heat.
Isocyanate (MDI) One of a group of neutral derivatives of primary amines (R-N=”C=O)” groups. An essential component (A) of spray foam chemistry.
Mold Fungal growths often resulting in deterioration of organic materials, especially under damp conditions.
Overspray (1) Airborne spray loss of polyurethane foam. (2) Undesirable depositions of airborne spray loss.
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.
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.
RSI A unit of measurement of resistance to heat flow in m2 ° C/W per 25 mm. R = 0.176 RSI
Retrofit The modification of an existing building or facility to include new systems or components.
Thermal Barrier A material applied over insulation, to slow the temperature rise of the foam during a fire so as to 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.
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 combination with other elements.
AISI American Iron & Steel Institute
ALA American Lung Association
ANSI American National Standards Institute
ASHRAE American Society for Heating Refrigeration and Air Conditioning Engineers
ASTM American Society for Testing and Materials
BETEC Building Environment & Thermal Envelope Council
BOCA Building Officials and Code Administrators
CABO (ICC) Conference of American Building Officials (International Code Council)
CCMC Canadian Construction Materials Centre
CSA Canadian Standards Association
DOE U.S. Department of Energy
EPA Environmental Protection Association
EEBA Energy Efficient Builders Association
EREC Energy Efficiency and Renewable Energy Clearing House (DOE program)
FSEC Florida Solar Energy Center
IBC International Building Code
ICBO International Conference of Building Officials
NAHB National Association of Home Builders
NAHBRC NAHB Research Center
NBC National Building Code of Canada
NEAT Novel Environmental Advanced Technology
NER National Evaluation Report
NIBS National Institute of Building Sciences
NIST National Institute of Standards and Technology
NRC National Research Council of Canada
ORNL Oak Ridge National Laboratories
SBCCI Southern Building Codes Congress International
UBC Uniform Building Code
UL Underwriter’s Laboratories
ULC Underwriter’s Laboratories Canada