Reflective Roof Coating Definitions
A B C D E F G H I K L M N O P Q R S T U V W
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ABAA
(See Air Barrier Association of America)
ABRASION RESISTANCE
The ability of a coating to resist degradation due to mechanical wear.
ABSOLUTE HUMIDITY
The actual concentration of water vapor in air. May be expressed in units of kPa, grains of moisture per pound of dry air, pounds of moisture per pound of dry air, or as a partial pressure as inches of mercury (in. Hg).
ABSORPTION
Process of attraction or attachment to a surface. The retention of foreign molecules on the surface of a substance.
AC-377 / ACCEPTANCE CRITERIA 377
The standard to which a specific formulation of SPF is evaluated by ICC-ES (International Code Council Evaluation Service) in order to issue an Evaluation Report which describes the foam’s compliance with building code requirements.
ACCELERATOR
A chemical additive to coating or polyurethane foam systems used in relatively small amounts to increase the speed of the re-action or decrease the time required to cure or dry.
ACRYLIC COATING
A coating system based on an acrylic resin. Generally, a “water based” coating system that cures by coalescence and air-drying.
ACRYLIC LATEX
An aqueous dispersion of acrylic resins.
ACRYLIC RESIN
A clear resin attained by polymerizing various acrylic monomers either alone or in combination.
ACRYLICS
Resins resulting from the polymerization of derivatives of acrylic acids, including esters of acrylic acid, methacrylic acid, acrylonitrile, and their copolymers. They can be carried in a water or solvent solution and they are film-forming materials.
ACTIVATOR
The curing agent of a two component coating system.
ADHESION
The degree of attachment or bonding of one substance to another. The degree of attachment or bonding between applications of the same substance. (For comparison, see also: COHESION)
AEROSOL
A suspension of fine solid particles or liquid droplets in a gas. In high-pressure foam and coating applications, liquid SPF chemicals and coating materials are formed into an aerosol in the spray gun by expulsion through a nozzle. (See ATOMIZATION).
AGGREGATE
Any mineral surfacing material. May include crushed gravel, river washed gravel, roofing granules, etc.
AGING
effect on materials that are exposed to an environment for an interval of time.
AGRICULTURAL CONTENT
See BIO-CONTENT.
AIR BARRIER
A material that 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 ASSOCIATION OF AMERICA (ABAA)
ABAA is an organization that promotes the use of air barriers; offers technical specifications to designers; and offers on-site inspections. It develops standards of proficiency in the industry through the ABAA On-Site Quality Assurance Program. ABAA offers training to installers, estimators, managers and administrators on the contractor side, as well as AIA accredited courses for design professionals. Some types of SPF are recognized as an air-barrier materials via product testing and certified contractors.
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.
AIR ENTRAPMENT
The inclusion of air bubbles in the liquid or coating film.
AIR EXFILTRATION
Air passing from the conditioned interior of a building to the exterior.
AIR FILTER RESPIRATOR
See RESPIRATOR.
AIR IMPERMEABLE
An insulation having an air permanence at a specific thickness that is equal to or less than 0.02 L/s•m2 at 75 Pa pressure differential (0.004 ft3/ft2•min at 1.57 lb/ft2) tested in accordance with ASTM E 2178 or E 283.
AIR INFILTRATION
Exterior air passing into the conditioned area of a building.
AIR LEAKAGE
The uncontrolled flow of conditioned air through gaps, cracks or holes in the building envelope or its components.
AIR PERMEABLE
An insulation having an air permanence at a specific thickness that is greater than 0.02 L/s•m2 at 75 Pa pressure differential (0.004 ft3/ft2•min at 1.57 lb/ft2) tested in accordance with ASTM E 2178 or E 283. See also: PERMEABILITY, AIR and PERMEANCE, AIR.
AIR PURIFYING RESPIRATOR (APR)
See RESPIRATOR.
AIR SUPPLIED RESPIRATOR
See RESPIRATOR.
AIRLESS SPRAY
A spraying system in which coating is atomized using high hydraulic pressure rather than compressed air.
ALIPHATIC (POLYURETHANE)
A type of polyurethane that does not contain carbon atoms arranged in aromatic (benzene) ring structures. As compared to AROMATIC (POLYURETHANE) (see also) coatings based on aliphatic polyurethane have superior resistance to UV weathering, and better color and gloss retention.
ALIPHATIC COATINGS
Two component products that are ultraviolet resistant. They will not discolor in sunlight.
ALKYD RESIN
Resins prepared by reacting alcohols and fatty acids. Widely used in general purpose coatings.
ALLIGATORING
Pattern cracking of a coating or mastic. So called because of its resemblance to the pattern of an alligator skin. (See CHECKING)
AMBIENT TEMPERATURE
Room temperature or the existing temperature of the surroundings.
AMINE CATALYST
A broad range of nitrogen-based compounds that are used to promote blowing and curing reactions in polyurethanes. Amine catalyst is typically contained in the B-side, or resin, of the two-component polyurethane system.
APPLICATION RATE
The quantity (mass, volume, or thickness) of material applied per unit area.
APR
Air Purifying Respirator (see RESPIRATOR).
AREA DIVIDER
A raised, flashed assembly (typically a single or double wood member attached to a wood base plate) that is anchored to the roof deck. It is used to relieve thermal stresses in a roof system where an expansion joint is not required, or to separate large roof areas (sometimes between expansion joints), and may be used to facilitate installation of tapered insulation.
AROMATIC (POLYURETHANE)
A type of polyurethane that contains some carbon atoms arranged in aromatic (benzene) ring structures. As compared to ALIPHATIC (POLYURETHANE) (see also) coatings based on aromatic polyurethane are usually tougher, but have less resistance to UV weathering, and poor color and gloss retention.
AROMATIC SOLVENTS
Hydrocarbon solvents comprised of organic compounds, which contain an unsaturated ring of carbon atoms, including benzene, xylene, toluene and their derivatives.
A-SIDE
(A-Component) One component of a two component system. For polyurethane – foam and coatings the isocyanate component. (See ISOCYANATE)
ASPHALT
A dark brown to black bituminous substance, solid or semi-solid in consistency, obtained from petroleum refining. It consists mainly of hydrocarbons. Asphalt products are available for hot or cold application. Asphalt will dissolve in mineral spirits.
ASTM
American Society for Testing and Measurement is a not-for-profit organization, which provides a forum for producers and consumers to meet on common ground and to write standards for materials, products, systems, and services.
ASTM INTERNATIONAL
Formerly known as American Society for Testing and Materials. A test standards development agency.
ATMOSPHERIC DISCOLORATION
Discoloration that may occur because of atmospheric contaminants such as sulfur-containing gases.
ATOMIZATION
The breakup of liquid or fluid in-to spray when forced through a small opening or orifice at high pressure.
ATTIC – UNVENTED
The unfinished space between the ceiling assembly of the top story and the roof assembly that has no openings to the outside adequate to promote natural or mechanical air exchange.
ATTIC – VENTED
The unfinished space between the ceiling assembly of the top story and the roof assembly that has openings to the outside adequate to promote natural or mechanical air exchange.
AY DOCUMENTS
Technical and informational documents published by the Spray Polyurethane Foam Alliance (SPFA) for use by members and distribution to the public. (The “AY” designation was developed as part of a numbering system by the Society of the Plastics Industries. All documents originating within the spray polyurethane foam organization were numbered “AY-xxx.”)
BACK ROLLING
Rolling wet coating behind a spray or roller application to insure better coverage on rough surfaces.
BARRIER COAT
A coating used to isolate a coating system either from the surface to which is applied or a
previous coating for the purpose of increasing adhesion or insuring compatibility.
BASE COAT
The first coat of a multi-coat system. This should be applied the same day as the spray polyurethane foam.
BASE FLASHING
(See Flashing.)
BASE PLY
The lowermost ply of roofing material in a roof membrane assembly.
BASE SHEET
A saturated or coated felt placed as the first ply in some multiply built-up roof membranes.
BINDER
The non-volatile portion of the vehicle of a coating which holds together the pigment particles.
BIO-CONTENT
Materials which are natural, non-petroleum based, that have harvest cycles of 10 years or less (per LEED [see also] standards). Bio-Content is determined by ASTM D 6866 where by the percentage of new carbon atoms are measured in relationship to old carbon atoms. All Bio-content claims shall be based on the finished foam product and not the individual raw materials.
BIRDBATH
Random, inconsequential amounts of residual water on a roof membrane.
BITUMEN
A class of amorphous, dark brown to black (solid, semi-solid, or viscous), high molecular weight hydrocarbons derived from petroleum refining (ASPHALT, see also) or coal reduction (COAL TAR, see also).
BITUMINOUS
Containing or treated with bitumen. Examples: bituminous concrete, bituminous felts and fabrics, bituminous pavement.
BITUMINOUS COATING
A coal tar or asphalt based coating material usually used in thick films.
BLEEDING
(1) The diffusion of coloring matter through a coating from its substrate (such as bleeding of asphalt mastic through coating). (2) The absorption of oil or vehicle from a compound into an adjacent porous surface.
BLISTER
An uplifting of coating or polyurethane foam caused by an enclosed pocket of gas or liquid entrapped between coating passes, foam and coating, foam and substrate, or within the foam itself. Caused by the DELAMINATION (see also) of one or two components in an insulation or roofing system.
BLOWHOLE
A hole in the polyurethane foam surface and/or coating surface about one millimeter in diameter (the size of a ballpoint pen tip). (See also: PINHOLE).
BLOWING AGENT
A chemical additive formulated into either the A-side or B-side which creates bubbles that are trapped in the polyurethane as it solidifies to form foam cells. The gas produced from the blowing agent contributes to over 97% of the volume of polyurethane foam. The blowing agent can be physical or reactive in nature. The physical blowing agents (for example, liquid fluorocarbon) vaporize with the heat of the polyurethane reaction, where a reactive blowing agent (for example, water) reacts with one of the other chemicals in the formulation to produce a gas during the reaction (for example, water and isocyanate yields carbon dioxide).
BOARD-FOOT
A volume measurement of materials such as SPF insulation, board-stock insulation and lumber. One board-foot equals a volume of 12 inches by 12 inches by 1 inch. Abbreviated bd•ft. (1 bd•ft = 1/12 cubic ft = 0.00236 m3).
BOCA
Acronym for Building Officials Code Administrators International. BOCA, once one of three model code agencies in the US, developed the National Building Code which had been commonly adopted in the Eastern and Midwestern United States. BOCA has been absorbed into the ICC (see also).
BOND
The adhesive and cohesive forces holding two roofing components in intimate contact.
BOND, CHEMICAL
Adhesion between surfaces, usually of similar materials, resulting from a chemical reaction or cross linking of polymer chains.
BOND, MECHANICAL
Adhesion between surfaces resulting from interfacial forces or a physical interlocking.
BREAKING STRENGTH
The amount of tension required to cause material or a system to give way or collapse. It is calculated by measuring the amount of force required to fracture a uniform sized sample.
B-SIDE
(B-component) One component of a two component system. For polyurethane foam and coatings the resin component. (See RESIN)
BUILDING CODE
A set of rules that establish the minimum acceptable levels of safety for constructed structures. Building codes also provide minimum standards for the energy consumption of structures. In the United States, model codes are developed and published by the International Code Council (ICC, see also) and the National Fire Protection Association (NFPA, see also). Model codes acquire legal standing when adopted by state or local authorities.
BUILDING ENVELOPE
The exterior shell of the building that provides structural integrity and control of heat, air and moisture.
BUILDING SCIENCE
Involves the application of basic science knowledge and analysis procedures to the design of buildings. There is a special knowledge and experience required, and such expertise is also beneficial in determining how to correct problems in existing buildings and to explain what went wrong to cause the problem.
BUILT-UP ROOF (BUR)
A roofing membrane consisting of alternating applications of bituminous impregnated felts (or fabrics) and hot (or cold) mopped bitumen. The membrane is generally surfaced with aggregate.
BUILT-UP ROOF MEMBRANES (BUR)
A continuous, semi-flexible roof membrane assembly, consisting of plies of saturated felts, coated felts, fabrics or mats between which alternate layers of bitumen are applied, generally surface with mineral aggregate, bituminous materials, or a granule surfaced roofing sheet.
BUTYL COATING
An elastomeric coating system derived from polymerized isobutylene. Butyl coatings are characterized by low water vapor permeability.
CANADIAN URETHANE FOAM CONTRACTORS ASSOCIATION
Also known as CUFCA, this is a national contractor organization promoting education, research and certification of SPF contractors and applicators throughout Canada.
CANT
A beveling of polyurethane foam at a right angle joint for strength and water runoff.
CANT STRIP
A beveled strip used under flashings to modify the angle at the point where the roofing or waterproofing membrane meets any vertical element.
CAP FLASHING
(See Flashing.)
CAP SHEET
A granule-surfaced coated sheet used as the top ply of a built-up roof membrane or flashing.
CAPACITANCE METER
A device used to detect moisture or wet materials within a roof system by measuring the ratio of the change to the potential difference between two conducting elements separated by a nonconductor.
CAPILLARITY
The action by which the surface of a liquid (where it is in contact with a solid) is elevated or depressed, depending upon the relative attraction of the molecules of the liquid for each other and for those of the solid.
CAPILLARY ACTION, CAPILLARITY
The movement of liquid in the interstices of insulation or other porous material as a result of surface tension.
CATALYST
An ingredient in a coating or polyurethane foam system that initiates a chemical reaction or increases the rate of a chemical reaction.
CATHEDRAL CEILING
A high, open, usually sloped or pointed ceiling. Unlike a standard ceiling, there is minimal airspace between the inside surface of the roof sheathing and the interior cladding or drywall.
CAULK
A flexible waterproofing material used to seal cracks, seams, or small breaks in a waterproofing or an air barrier system. Usually supplied in tubes and applied with a caulking gun. (See SEALANT)
CAVITATION
The vaporization of a liquid under the suction force of a pump. Usually due to inadequate flow to a pump; the vaporization can create voids within the pump or the pump supply line. In polyurethane foam spray pumps, cavitation will result in OFF-RATIO FOAM (see also).
CAVITY WALL
An exterior wall, usually of masonry, consisting of an outer and inner wythe separated by a continuous air space.
ccSPF
Closed-cell SPF. See MEDIUM-DENSITY SPF.
CELLULAR
Describes a composition of plastic or rubber with relative density decreased by the presence of cells dispersed throughout its mass. In closed-cell materials, the cells are predominately separate from each other. In open-cell materials, the cells are predominately interconnected.
CENTIPOISE
(cps) A unit of measure of absolute viscosity. (Note: The viscosity of water is one centipoise. The lower the number, the less the viscosity.)
CFC
Chlorofluorocarbon. A physical blowing agent containing at least one carbon, one fluorine and one chlorine atom in its structure (for example: CFC-11). Their use was phased out in the US as a spray foam blowing agent between 1993 and 1996.
CHALKING
The formation on a coated surface of a powdery substance due to weathering.
CHECKING
A defect in a coated surface characterized by the appearance of fine fissures in all directions. Designated as “surface checking” if superficial, or “through checking” if extending deeply into the coating or to an adjoining surface.
CHEMICAL BOND
See BOND, CHEMICAL
CHEMICAL RESISTANCE
The ability to withstand contact with specified chemicals without a significant change in properties.
CHLORINATED RUBBER
Resin formed by the reaction of rubber and chlorine to form a coating (i.e. primer or Hypalon®) or single ply membrane.
CLOSED-CELL SPF
See MEDIUM-DENSITY SPF.
COAL TAR
A dark brown to black hydrocarbon obtained from the destructive distillation of coal. Used in built-up roofs or in below grade construction as a waterproofing agent. Coal tar when mixed with mineral spirits will produce a yellow- green to amber color, but will not dissolve.
COALESCENCE
The formation of a film of resinous or polymeric material when water evaporates from an emulsion or latex system, permitting contact and fusion of adjacent latex particles. Action of the joining of particles into a film as the volatile evaporates.
COARSE ORANGE PEEL SURFACE TEXTURE
A surface showing a texture where nodules and valleys are approximately the same size and shape. This surface is acceptable for receiving a protective coating because of the roundness of the nodules and valleys. This surface requires at least 25% additional material to the theoretical amount. (See AY-145 Surface Texture of Spray Polyurethane Foam.)
COATED SHEET FELT
(1) an asphalt felt that has been coated on both sides with harder, more viscous asphalt;
(2) a glass fiber felt that has been simultaneously impregnated and coated with asphalt on both sides.
COATING
A layer of material applied over a surface for protection or decoration. Coatings for polyurethane foam are liquids, semi-liquids, or mastics; spray, roller, or brush applied; and are elastomeric. (See ELASTOMERIC)
COBWEBBING
Production of fine filaments instead of the normal atomized particles when some coatings are sprayed.
COEFFICIENT OF THERMAL EXPANSION
A mathematical formulation used to predict the change in dimension (typically length) of a material as a function of temperature change.
COHESION
The degree of internal bonding of one substance to itself. (See ADHESION)
COLD APPLIED
Capable of being applied without heating as contrasted to hot- applied. Cold-applied products are furnished in a liquid state, whereas hot-applied products are furnished as solids that must be heated to liquefy them.
COLD-PROCESSING ROOFING
A continuous, semi-flexible roof membrane, consisting of plies of felts, mats, or fabrics Roofing: that are laminated on a roof with alternate layers of cold-applied roof cement and surfaced with a cold-applied coating.
COLLECTOR BOX
(See CONDUCTOR HEAD)
COLLOIDAL DISPERSION
A mixture wherein a finely divided material is uniformly distributed within a liquid. Latex emulsion is a colloidal dispersion of resin in water. (See LATEX)
COLOR STABILITY
The ability to retain the original color without significant change over time.
COMBUSTIBLE
Capable of burning.
COMPARATOR
An eyepiece with magnification ranging from 4-12 power, with a scale used for measuring thickness.
COMPATIBLE MATERIALS
Two or more substances that can be mixed, blended, or attached without separating, reacting, or affecting the materials adversely.
COMPRESSIVE STRENGTH
The stress or force applied parallel to the direction of the polyurethane foam rise at 10% deformation or at yield point.
CONDENSATE
The liquid resulting from the CONDENSATION (see also) of a gas or vapor.
CONDENSATION
The conversion of water vapor or other gas to liquid as the temperature drops or the atmospheric pressure rises. (See Dew-Point.)
CONDITIONED CRAWLSPACE
See CRAWLSPACE, UNVENTED.
CONDITIONING
The exposure of a material to the influence of a prescribed atmosphere for a stipulated period of time or until a stipulated relation is reached between material and atmosphere.
CONDUCTOR HEAD
A transition component between a through-wall scupper and downspout to collect and direct run-off water.
CONTINUOUS INSULATION (C.I.)
Insulation that is continuous across all structural members without thermal bridges other than fasteners and service openings. It is installed on the interior or exterior or is integral to any opaque surface of the building envelope.
CONTROL JOINT
(See AREA DIVIDER)
COOL ROOF
(1) A roof system which tends to reflect solar energy away from the roof surface and/or emit non-reflected solar energy away from the roof surface such that less solar energy is absorbed into the building, thus reducing cooling loads. Reflective cool roofs are generally white or other light color. Cool roofs may be rated by the Cool Roof Rating Council, Energy Star or other organizations. (2) Any roof system which exhibits energy load performance similar to a cool roof.
COPING
The covering piece on top of a wall exposed to the weather, usually sloped to shed water.
COPOLYMER
A polymer consisting of molecules containing large numbers of units two or more chemically different types in irregular sequence.
CORE SAMPLE
The actual material of a cross section of the roofing material, insulation, etc. showing the various layers.
COUNTERFLASHING
Formed metal or elastomeric sheeting secured on or into a wall, curb, pipe, roof-top unit, or other surface to cover and protect the upper edge of a base flashing and its associated fasteners.
COURSE
(1) the term used for each application of material that forms the waterproofing system or the flashing;
(2) one layer of a series of material applied to a surface (i.e., a five-course wall flashing is composed of three applications of mastic with one ply of felt sandwiched between each layer of mastic).
COVERAGE
The unit quantity of material necessary to apply to achieve a desired thickness. Usually expressed in (square feet per gallon) square meter per liter or (gallons per hundred square feet) liters per square meter.
CPI
Center for the Polyurethanes Industry, a division of the American Chemistry Council, whose members include producers or distributors of chemicals and equipment used to make polyurethane products.
cPVC
Chlorinated polyvinylchloride. A thermoplastic resin used to form sprinkler and high temperature water piping and fittings.
CRACK
A separation or fracture occurring in a roof membrane or roof deck, generally caused by thermal induced stress or substrate movement.
CRAWLSPACE, UNVENTED
A low space beneath the floor of a building, giving workers access for the service of utilities, which is not ventilated to the exterior of the building envelope. Insulation is typically installed in the crawlspace walls. Also known as “conditioned crawlspace.”
CRAWLSPACE, VENTED
A low space beneath the floor of a building, giving workers access for the service of utilities, which is ventilated to the exterior of the building envelope. Insulation is typically installed in the crawlspace overhead (beneath the floor of the building).
CRAZING, CRAZE CRACKS
Fine, random cracks in forming a network on the surface of a coating or film.
CREAM TIME
After mixing the two SPF-forming components the cream time occurs when the mixture changes from a clear dark-colored liquid to an opaque light-colored liquid. The cream time represents the onset of the rise of the foam.
CREEP
(1) The permanent deformation of a material caused by slow movement over time resulting from thermal or load stresses. (2) Lateral movement of expanding foam.
CRICKET
A relatively small, elevated area designed to facilitate the flow of water around an obstruction on a roof such as a chimney or skylight.
CROSS HATCH
An application method for liquid applied materials whereby successive layers or passes are applied at 90 degrees to the previous application.
CROSSOVER
An undesirable mixing of iso- and resin-components as a result of unbalanced pressures at the spray gun. May result in an equipment blockage.
CUFCA
See: Canadian Urethane Foam Contractors Association.
CURE
The completeness of the chemical reaction. At substantial completion, the foam should have near the maximum physical properties attainable for the particular formulation used. Cure is not directly related to levels of product emissions during or after SPF application
CURE TIME
The time required for a foam to achieve substantial completion of reaction
CURING AGENT
An agent in a coating or adhesive that increases the rate of cure.
CURTAIN WALL
A lightweight exterior wall system supporting no more than its own weight, the roof and floors being carried by an independent structural framework.
CUTBACK
Solvent-thinned bitumen used in cold process roofing adhesives, flashing cements and roof coatings.
CUTOFF
A detail designed to prevent lateral water movement into the insulation where the membrane terminates at the end of a day's work, or used to isolate sections of the roofing system. It is usually removed before the continuation of the work.
DAMPPROOFING
Treatment of a surface or structure to resist the passage of water in the absence of hydrostatic pressure.
DEAD LEVEL
Absolutely horizontal, or zero slope.
DEAD LOADS
The weight imposed on a structural roofing system, including the waterproofing system, roof mounted equipment, roof structural members, and anything hung from the roof structure.
DEAD-LEVEL ASPHALT
(See Asphalt.)
DECK
The structural surface to which a roofing or waterproofing system is applied. SPF may be applied to decks on the exterior side as an insulated roofing system or to the interior side as an insulation system.
DEFLECTION
The deviation of a structural element from its original shape or plane due to physical loading, temperature gradients, or movement of its support.
DEGRADATION
The deterioration of a substance caused by contact with its environment.
DELAMINATION
The separation of layers within a material or materials. May result in BLISTER (see also) formation.
DESSICANT
A substance which attracts water molecules from the surround-ing environment through absorption. Typically used to dry compressed air or dry makeup air entering chemical storage containers.
DEW POINT
The temperature at which water vapor starts to condense in cooling air at the existing atmospheric pressure and vapor content.
DIFFUSION
The process in which there is movement of a substance from an area of high concentration of that substance to an area of lower concentration, typically through or across a membrane. For example: Water vapor diffusing from a humid bathroom into the bathroom walls resulting in moisture in the wall assembly.
DIISOCYANATE
An organic chemical compound having two reactive isocyanate ( N=C=O) groups; used in the production of polyurethane foams and polyurethane coatings.
DIMENSIONAL STABILITY
The ability of a material to retain its original size and shape. For polyurethane foam, dimensional stability is determined over time under conditions of controlled temperature and humidity. Measured as a percent of original dimension.
DIRT ACCUMULATION
Soiling by foreign material other than microorganisms deposited on or embedded in the dried coating.
DISCOLORATION
Any change from the initial color. (See COLOR STABILITY)
DOUBLE-POUR
The process of applying two layers of aggregate and bitumen to a built-up roof.
DRAFTSTOP
A material, device or construction installed to restrict the movement of air and smoke within open spaces of concealed areas of building components such as crawl spaces, floor/ceiling assemblies, roof/ceiling assemblies and attics.
DRAINAGE
(See POSITIVE DRAINAGE)
DRIFT
Airborne or windborne movement of atomized droplets or particles away from the surface being coated
DRIP EDGE
A projecting piece of material shaped to throw off water and prevent its running down the face of the wall or other surface.
DRY BULB TEMPERATURE
The temperature of air as measured by an ordinary thermometer.(See AMBIENT TEMPERATURE)
DRYING TIME
The time required for the loss of volatile components so that the material will become tack free and no longer be adversely affected by weather conditions such as dew, rain or freezing. (Contrast with, CURE TIME).
EDGE SHEETS
Felt strips that are cut to widths narrower than the standard width of the full felt roll, used to start the felt shingling pattern at a roof edge.
EDGE STRIPPING
Application of felt strips cut to narrower widths than the normal felt roll width to cover a joint between flashing and built-up roofing.
EDGE VENTING
The practice of providing regularly spaced protected opening along a roof perimeter to relieve moisture vapor pressure.
ELASTOMER
A material which at room temperature is capable of being stretched repeatedly at least twice its original length (100% elongation) and, upon release of stress, will return to its original dimensions. (See ELONGATION)
ELASTOMERIC
The elastic, rubber-like properties of a material that will stretch when pulled and will return relatively quickly to its original shape when released.
ELASTOMERIC COATING
A coating system which, when fully cured, is capable of being stretched at least twice its original length (100% elongation) and recovering to its original dimensions. (See ELONGATION)
ELONGATED CELLS
Excessively large cells in foam or coating generally caused by off-ratio materials, moisture contamination, or excessive heat.
ELONGATION
The increase in length of a specimen at the instant that rupture occurs (expressed as a percent of the original length).
EMBEDMENT
(1) the process of pressing a felt, aggregate, fabric, mat, or panel uniformly and completely into hot bitumen or adhesive;
(2) the process of pressing granules into coating in the manufacture of factory prepared roofing.
EMBODIED ENERGY
The quantity of energy required to manufacture, and supply to the point of use, a product, material or service.
EMISSIVITY
The ability of a material to radiate or absorb radiant energy. Emissivity is usually expressed as a number (0 – 1) or a percentage (0% - 100%) which is determined at infrared wavelengths; the higher the number the greater the ability of material to absorb and radiate infrared radiation.
EMISSIVITY
Infrared emissivity (emittance) is a measure of the ability of a surface to shed some of its “absorbed” heat (in the form of infrared radiation) away from the surface; emissivity is expressed as a percentage or a decimal factor.
EMULSION
A colloidal dispersion of one liquid in another. (See LATEX; COLLOIDAL DISPERSION)
ENVELOPE
A continuous membrane edge seal formed at the perimeter and at penetrations by folding the base sheet or ply over the plies above and securing it to the top of the membrane. The envelope prevents bitumen seepage from the edge of the membrane.
EPOXY
A class of synthetic, thermosetting resins, which produce tough, hard, chemical-resistant coatings and adhesives.
EROSION
Wearing away of a coating by chalking or the abrasive action of water or windborne particles of grit.
ESR
See EVALUATION SERVICE REPORT.
EVALUATION SERVICE REPORT
An evaluation report presenting the findings of ICC-ES (International Code Council Evaluation Service) as to the compliance with building code requirements of the subject of the report—a particular building product, component, method or material.
EXOTHERMIC REACTION
A chemical reaction that produces heat. SPF and certain coatings are the product of exothermic reactions.
EXPANSION JOINT
A joint designed to accommodate movement in the structure or components of the system due to thermal or stress-load variation.
EXPOSURE
(1) the transverse dimension of a roofing element not overlapped by an adjacent element in any roof system. The exposure of any ply in a membrane may be computed by dividing the felt width minus 2 inches by the number of shingled plies.
(2) the time during which a portion of a roofing element is exposed to the weather.
FACTORY MUTUAL (FM)
An organization that classifies roof assemblies for their fire characteristics and wind uplift resistance for insurance companies in the United States.
FAST SET
A term applied to a coating to indicate a faster curing time versus a standard version of the generic coating. In polyurethane and polyurea coatings this is generally indicative of cure times in the range a few seconds to a few minutes or coatings that must be sprayed with plural component equipment. In acrylic coatings, this is generally indicative of a 1-3 hour cure schedule versus 2-5 hour at 75°F.
FEATHERED EDGE
The thin tapered outside edge of a polyurethane foam pass.
FELT
A flexible sheet manufactured by the interlocking of fibers through a combination of mechanical work, moisture and heat. Felts are manufactured principally from vegetable fibers (organic felts), or glass fibers (glass fiber felts); other fibers may be present in each type.
FELTS
A flexible sheet manufactured by the interlocking of fibers through a combination of mechanical work, moisture, and heat. Roofing felts may be manufactured principally from wood pulp and vegetable fibers (organic felts), asbestos fibers (asbestos felts), glass fibers (fiberglass felts or ply sheet), or polyester fibers.
FERROUS METAL
An iron compound, i.e., steel, cast iron, or galvanized steel. As a rule of thumb, most ferrous metals are magnetic.
FILLER
A relatively inert ingredient added to coating or polyurethane foam formulations to modify physical characteristics.
FILM THICKNESS
The thickness of a membrane or coating. Wet film thickness is the thickness of a coating as applied; dry film thickness is the thickness after curing. Film thickness is usually expressed in mm or mils (thousandths of an inch).
FINE MINERAL SURFACING
A Water-insoluble, inorganic material, more than 50 percent of which passes the No. 35 sieve, used on the surface of roofing.
FIRE RESISTANCE
The inherent capability of a building assembly, or an element of construction, to resist the passage of heat, smoke and flame and/or maintain structural integrity for a specified time during a fire. Usually measured by ASTM E 119.
FIREBLOCKING
Building materials or constructions designed, approved and installed to resist the free passage of flame to other areas of the building through concealed spaces.
FIRESTOP
A material, device or construction, installed to resist for a prescribed time period, the passage of flame and heat through openings in a protective membrane in order to accommodate cables, cable trays, conduit, tubing, pipes or similar items.
FISHEYE
Coating defect that manifests itself by the separation of wet coating into a recognized pattern resembling small “dimples” or “fish eyes”.
FISHMOUTH
(Also referred to as ”edge wrinkle.”) 1) A half-cylindrical or half- conical shaped opening or void in a lapped edge or seam, usually caused by wrinkling or shifting of ply sheets during installation; 2) In shingles a half-conical opening formed at a cut edge.
FLAKING
The actual detachment of film fragments from the previously applied coating or substrate.
FLAME RETARDANT
A substance that is added to a coating or polyurethane foam formulation to reduce or retard its tendency to burn.
FLAME SPREAD
Per ASTM E 84, a measure of relative combustibility. The flame spread of a tested material is rated relative to fiber cement board (flame spread = 0) and red oak flooring (flame spread = 100).
FLAMMABILITY
Relative ability of a material to support combustion as expressed by its flash point.
FLASH AND BATT
See HYBRID INSULATION.
FLASH COAT
A thin initial pass of a spray-applied material.
FLASH IGNITION TEMPERATURE
The lowest temperature of a material required to initiate combustion in the presence of a spark or flame.
FLASH OVER
A fire condition wherein gasses are ignited at the ceiling level of a room. Also: One of several measurements that are used to determine the threshold at which a fire test is terminated. Flash Over can be a visual observation of flames exiting the structure or a measured heat flux or temperature limit.
FLASH POINT
The lowest temperature of a material at which it gives off vapors sufficient to form an ignitable mixture with air near its surface.
FLASHING
The system used to seal membrane edges at walls, expansion joins, drains, gravel stops, and other places where the membrane is interrupted or terminated. Base flashing covers the edge of the membrane. Cap flashing or counterflashing shields the upper edges of the base flashing.
FLASHING CEMENT
A trowelable mixture of cutback bitumen and mineral stabilizers, including organic or other inorganic fibers.
FLOOD COAT
The top layer of bitumen into which the aggregate is embedded on an aggregate-surfaced built up roof.
FLOW PROPERTIES
The ability of a coating to move freely as a liquid, allowing it to achieve a level surface.
FLUID APPLIED
An elastomeric material, fluid at ambient temperature, that dries or cures after application to form a continuous membrane. Such systems normally do not incorporate reinforcement.
FLUOROCARBONS
A chemical that contains both a carbon and a fluorine atom in its structure. They are traditionally used as physical blowing agents for polyurethane foam products. There are three common classes of these material used as blowing agents (CFC, HCFC, HFC).
FLUTES
The grooves in the lower section of metal decking that give it added strength.
FM
See FM GLOBAL.
FM APPROVALS
A division of FM Global (formerly Factory Mutual) that certifies industrial and commercial products and services as meeting their established safety standards for insurance rating purposes and publishes such certifications in their Approval Guide.
FM GLOBAL
Formerly Factory Mutual or FM. A U.S.-based insurance company that specializes in loss prevention services. The company employs a business model which determines risk and premiums through engineering analysis as opposed to historically based calculations. (See also: FM APPROVALS.)
FMRC
Factory Mutual Research Corporation. A part of FM.
FOAM STOP
The roof edge treatment upon which polyurethane foam is terminated.
FREEZE THAW CYCLE
The freezing and subsequent thawing of material.
FRIABILITY
The tendency of a material or product to crumble or break into small pieces easily.
FROTH PACK
Pressurized containers of polyurethane foam components.
GLASS EYES or GLASS WINDOWS
A thin clear membrane that forms over elongated polyurethane foam cells. Glass eyes may break when coated, forming a PINHOLE (see also).
GLASS FELT
Glass fibers bonded into a sheet with resin and suitable for impregnation in the manufacture of bituminous waterproofing materials, roof membranes, and shingles.
GLASS MAT
A mat composed of glass fibers with or without a binder.
GLOSS
The shine, sheen, or luster of a dried film.
GRANULE
Size No. 11 ceramic aggregate embedded into wet coating over polyurethane foam for aesthetics, traction, and mechanical resistance.
GRAVEL STOP
A flanged device, frequently metallic, designed to provide a continuous finished edge for roofing material and to prevent loose aggregate from washing off of the roof.
HARDNESS
Ability of a coating film, as distinct from its substrate, to resist cutting, indentation, or penetration by a hard object.
HCFC
Hydrochlorofluorocarbon. A physical blowing agent containing at least one carbon, one fluorine, and one chlorine atom in its structure (for example: HCFC-141b). Effective January 1, 2005, the U.S. Environmental Protection Administration (EPA) issued a "Use Ban" regulation on HCFC-141b blowing agent, meaning that SPF systems containing HCFC141b could not be domestically produced or imported, under penalty of law, after this date. The regulation also required that any existing inventory of finished product containing HCFC 141-b could not be applied after June 30, 2005.
HEAT AGING
Controlled exposure of materials to elevated temperatures for a period of time.
HEAT FLUX
The rate of heat transfer per unit area. Usually used to describe the rate of radiant heat transfer. Units are W/m2 (Btu/ft2•hr).
HEAT SINK
A cold substrate that absorbs the SPF exothermic heat, slowing down the reaction and/or rise of the polyurethane foam or coating.
HERS
See HOME ENERGY RATING SYSTEM.
HFC
Hydrofluorocarbon. A physical blowing agent containing at least one carbon and one fluorine atom in its structure (for example: HFC-245fa).They have no ozone depletion potential.
HIDING POWER
The ability of a coating to hide or obscure a surface to which it has been uniformly applied.
HIGH PRESSURE SPF
See SPF, HIGH PRESSURE.
HOLIDAY
An area where a liquid-applied material is missing.
HOLIDAYS
Application defects whereby small areas are left uncoated.
HOME ENERGY RATING SYSTEM (HERS)
HERS is a rating system for residential energy efficiency developed by EnergyStar and RESNET. Through a comprehensive design review and analysis, it incorporates HVAC, building enclosure and orientation, as well as appliance and lighting selection. A HERS score of 0 indicates a net zero-energy home, while a HERS score of 100 represents the energy consumption of home built to the 2003 IECC model energy code. A maximum HERS score of 70 is required for a home to be EnergyStar compliant.
HYBRID INSULATION
A combination of insulation types typically arranged so the SPF insulation acts as an air barrier and/or a vapor retarder, and the other insulation type contributes by adding R-Value.
HYDROPHILIC
Having an affinity or attraction for water; having the ability of uniting with or dissolving in water. "Water loving."
HYDROPHOBIC
Having no affinity for water; not compatible with water. "Water fearing"
HYGROSCOPIC
Attracting, absorbing, and retaining atmospheric moisture.
HYGROSCOPICITY
The capacity of a compound or substance to absorb water.
ICAA
Insulation Contractors Association of America.
ICBO
Acronym for International Conference of Building Officials. ICBO, once one of three model code agencies in the US, developed the Uniform Building Code (UBC, see also) which had been commonly adopted in the Western United States. ICBO has been absorbed into the ICC (see also).
ICC
See INTERNATIONAL CODE COUNCIL.
ICE DAM
A mass of ice formed at the transition from a warm to a cold roof surface, frequently formed by refreezing meltwater at the overhang of a steep roof, causing ice and water to back up under roofing materials.
I-CODES
The set of model building codes promulgated by the International Code Council (ICC, see also). The I-Codes include the International Residential Code (IRC), the International Building Code (IBC), the International Energy Conservation Code (IECC), the International Mechanical Code, and others.
IECC
See INTERNATIONAL ENERGY CONSERVATION CODE.
IGNITION BARRIER
A building code permitted protective covering applied over foam plastic insulations, including SPF, in attics and crawlspaces to increase the time it takes for the foam plastic to become involved in a fire. Ignition barriers do not provide as much fire protection as THERMAL BARRIERS (see also). The building code restricts the use of ignition barriers to attics and crawlspaces of limited access (check the local building code for exact requirements).
IGNITION TEMPERATURE
See FLASH IGNITION TEMPERATURE.
IMPACT RESISTANCE
Ability to withstand mechanical or physical blows without the loss of protective properties. The impact resistance of the roofing assembly is a function of all its components not just the membrane itself.
IMPINGEMENT MIXING
A process of mixing in which multiple liquid streams are forced toward one another at high velocity, producing very thorough mixing in a short time.
INCLINE
The slope of a roof expressed either in percent or in the number of vertical units of rise per horizontal unit of run.
INFRA-RED THERMOGRAPHY
Photography in the infra-red wave length wherein the temperature differences of objects and surfaces can be readily distinguished. Infra-red thermography is frequently used to (1) identify sources of heat loss or gain which effect building energy efficiency; (2) identify sections of building assemblies containing moisture; and (3) identify electrical or mechanical components which are overheating.
INTERLAMINAR ADHESION
Adhesion between polyurethane foam passes or coating passes. See also: COHESION.
INTERNATIONAL BUILDING CODE (IBC)
Revised every three years, one of the I-CODES (see also) promulgated by the International Code Council (ICC, see also) oriented toward general construction other than one- and two-family dwellings (which are covered under the International Residential Code [IRC, see also]).
INTERNATIONAL CODE COUNCIL (ICC)
The ICC formed in 1994 by the merger of BOCA (see also), ICBO (see also) and SBCCI (see also) to promulgate a common set of model building codes. Codes developed by the ICC are commonly referred to at the I-Codes (see also).
INTERNATIONAL ENERGY CONSERVATION CODE (IECC)
A model building code promulgated by the ICC (see also) designed to set minimum standards of energy conservation for buildings. The IECC is one of the I-Codes (see also) and is revised every three years.
INTERNATIONAL RESIDENTIAL CODE (IRC)
A model building code promulgated by the ICC (see also) designed to set minimum standards of residential construction (one- and two-family dwellings). The IRC is one of the I-Codes (see also) and is revised every three years.
INTUMESCENT COATING
Coatings which are formulated to swell and char when exposed to heat. When applied to a combustible (or non-combustible) substrate, this “swollen char” is designed to insulate the substrate from the heat source, thus reducing the potential and/or increasing the time that the substrate becomes involved in a fire.
IRC
See INTERNATIONAL RESIDENTIAL CODE.
ISO
Vernacular for isocyanate.
ISOCYANATE
A highly reactive organic chemical containing one or more isocyanate (N-N=C=O) groups. A basic component in polyurethane foam chemical systems and some polyurethane coating systems.
ISOCYANURATE
Also referred to as PIR, polyiso, or polyisocyanurate, it is essentially a modified polyurethane (PUR) foam. The proportion of methylene diphenyl diisocyanate (MDI) is higher than for PUR and instead of a polyether polyol resin, a polyester derived polyol is used in the reaction. Catalysts, blowing agents and additives used in PIR foam formulations also differ from those used in PUR. Isocyanurates are generally manufactured in a factory into boardstock form and are used in exterior roofing and sheathing applications. Thermal performance of isocyanurate or PIR boardstock foams are comparable to medium-density closed-cell SPF.
k-FACTOR
Thermal conductivity for a unit thickness of material. Expressed as W/m2•K (Btu•in/hr•ft2•F). R-VALUE (see also) is equal to the thickness of the material divided by the k-factor (R = x/k where x = thickness).
KNIT LINE
A high density skin formed between one lift or pass of foam and another Synonymous with LIFT LINE.
KREBS UNITS (K.U.)
A measurement of viscosity for materials that have the property of changing resistance to flow when under shear. Such materials are called THIXOTROPIC (see also). Measuring is done with a Krebs/Stormer viscometer.
LAITANCE
A layer of weak non-durable material containing cement and fines, brought by bleeding water to the top of over wet concrete. Laitance may be detected by scraping the concrete surface with a putty knife; if a quantity of loose powdery material is observed or easily removed, excessive laitance may be considered to be present.
LATEX
A colloidal dispersion of a polymer or elastomer in water that coalesces into a film upon evaporation of the water. (See EMULSION; COLLOIDAL DISPERSION)
LCA
See LIFE CYCLE ASSESSMENT.
LEADER HEAD
See CONDUCTOR HEAD.
LEADERSHIP IN ENERGY AND ENVIRONMENTAL DESIGN (LEED)
Commonly referred to as LEED, it is a prominent green building rating system, developed by the U.S. Green Building Council (USGBC), that provides a suite of standards for environmentally sustainable construction. Energy efficiency, through proper application of insulation and air sealing technologies, plays an important role in the LEED evaluation process.
LEED
See LEADERSHIP IN ENERGY AND ENVIRONMENTAL DESIGN.
LIFE CYCLE ANALYSIS
See LIFE CYCLE ASSESSMENT
LIFE-CYCLE ASSESSMENT (LIFE-CYCLE ANALYSIS, LCA)
An accounting and evaluation of the environmental aspects and potential impacts of materials, products, assemblies, or buildings throughout their life, from raw material acquisition through manufacturing, construction, use, operation, demolition and disposal.
LIFE-CYCLE INVENTORY (LIFE-CYCLE INVENTORY ANALYSIS, LCI, LCIA)
The identification and quantification of energy, resource usage and environmental emissions for a particular product, process or activity.
LIFT
The sprayed polyurethane foam resulting from passes of foam in a specific area. A lift is defined by its thickness and the area. For example, a one inch lift of foam was installed to a 20 x 20 ft area, and then a second lift of foam 1.5 inch thick was installed to the same area. (See also: PASS).
LIFT LINE
See KNIT LINE.
LIVE LOAD
The weight on a roof of temporary, mobile loads such as foot traffic, roofing equipment, water, snow, and ice.
LOW PRESSURE SPF
See SPF, LOW PRESSURE.
LOW TEMPERATURE FLEXIBILITY
The ability of a membrane or other material to remain flexible (resist cracking when flexed), after it has been cooled to a low temperature.
LOW-DENSITY SPF (Open-cell SPF, ocSPF)
A type of spray polyurethane foam expanded with reactive blowing agents to yield a semi-rigid cellular structure and a density between 8 and 22 kg.m3 (0.5 and 1.4 lb/ft3).
MATERIAL SAFETY DATA SHEET (MSDS)
A standard formatted information sheet prepared by a material manufacturer which describes the potential hazards, physical properties, and procedures for safe use of a material.
MDI
See METHYLENE DIPHENYL DIISOCYANTE.
MECHANICAL BOND
(See BOND, MECHANICAL)
MECHANICAL DAMAGE
Breaks or punctures to insulation and coating systems as a result of impact or abrasion.
MEDIUM-DENSITY SPF (Closed-cell SPF, ccSPF)
A type of spray polyurethane foam expanded with non-reactive blowing agents to yield a rigid cellular structure. It is characterized by a predominance of closed-cells and a density between 1.5 and 2.5 lb. per cubic foot.
MEMBRANE
A layer of material which acts to prevent the passage of a substance. Membranes may restrict the passage of air, liquid water or water vapor. Some membranes allow the passage of some substances while excluding others.
MEMBRANE REINFORCEMENT
Fabrics or fibers embedded in mastic or coating to provide strength and impact resistance.
METHYLENE DIPHENYL DIISOCYANATE (MDI)
Component-A in spray polyurethane foam. An organic chemical compound having two reactive isocyanate (-N=C=O) groups. It is mixed with the B component to form polyurethane.
MIL
One-thousandth of an inch; 0.001 inch (0.025 mm). A unit used to measure coating thickness.
MILDEW
A superficial coating or discoloring of an organic material due to fungal growth, especially under damp conditions.
MINERAL-SURFACED ROOFING
Built-up roofing materials whose top ply consists of a granule-surfaced sheet.
MIST COAT
A very thin sprayed coat.
MODIFIED BITUMENT
Composite sheets consisting of a copolymer modified bitumen often reinforced and sometimes surfaced with various types of films, foils, and mats.
MOISTURE VAPOR TRANSMISSION (MVT)
(See WATER VAPOR TRANSMISSION, DIFFUSION)
MOLD
Fungal growths often resulting in deterioration of organic materials, especially under damp conditions.
MONOLITHIC
Formed from or composed of a single material; seamless.
MSDS
See MATERIAL SAFETY DATA SHEET.
MUD CRACKING
The defect in an applied coating or mastic when it cracks into large segments or shrinks (also called alligatoring). When the action is fine and incomplete, it is usually referred to as "checking."
MULTIPLE COAT
Two or more layers of coating applied to a substrate.
NEOPRENE
A synthetic rubber (polychloroprene) used in liquid-applied and sheet applied elastomeric roof membrane or flashings.
NEOPRENE RUBBER
A synthetic rubber having physical properties closely resembling those of natural rubber. Made by polymerization of chloroprenes.
NFPA
National Fire Protection Association. The NFPA promotes safety from fire and other hazards through the promulgation of codes, standards, research, training and education.
NIGHT SEAL
A material and or method used to temporarily seal a membrane edge during construction to protect the roofing assembly in place from water penetration. May be removed when roofing application is resumed.
NOISE REDUCTION COEFFICIENT (NRC)
A representation of the amount of sound energy absorbed upon striking a particular surface. An NRC of 0 indicates perfect reflection (strong echo), an NRC of 1 indicates perfect absorption (lack of echo).
NON-BREATHING MEMBRANE
A membrane material that has a significantly greater resistance to the diffusion of water vapor than the other materials with which it is used.
NON-FERROUS METAL
All metals that are not iron compounds, i.e., copper, lead, gold, silver, and aluminum. These metals are non-magnetic.
NON-FLAMMABLE
Not easily ignited and will not burn rapidly if ignited. The material may still burn and be considered combustible. OSHA defines a flammable liquid as any liquid having a flashpoint below 100 F (37.8 C).
NON-OXIDIZING
A material that resists oxidation in exterior exposures or accelerated weathering.
NON-VOLATILE CONTENT
That portion of a coating material that does not evaporate under normal ambient conditions. (For Comparison See SOLIDS CONTENT)
NRCA
National Roofing Contractors Association.
ocSPF
Open-cell SPF. See LOW-DENSITY SPF INSULATION.
OFF-GASSING
See OUTGASSING.
OFF-RATIO FOAM
An off-ratio foam is caused by a deficiency of one of the component chemicals (A- or B-side) during application. The reaction of an off-ratio foam is readily visible to the trained SPF applicator. Off-ratio foam will negatively affect SPF yield, performance, and worker safety.
ONE-COMPONENT FOAM
See SINGLE-COMPONENT FOAM.
OPEN-CELL SPF
See LOW-DENSITY SPF INSULATION.
ORANGE PEEL SURFACE TEXTURE
The surface texture of spray polyurethane foam which exhibits a fine granular texture and is compared to the exterior skin of an orange. This surface is considered acceptable for receiving a protective coating. This surface requires at least 10% additional coating material to the theoretical amount. (See AY-145 Surface Texture of Spray Polyurethane Foam.)
ORGANIC
Compounds containing carbon.
ORIFICE
An opening or aperture. The opening in the tip of a spray gun.
OUTGASSING
The slow release of a gas that was trapped, frozen, absorbed or adsorbed in some material. (Sometimes called “offgassing,” particularly when in reference to indoor air quality,)
OVERSPRAY
(1) Airborne spray loss of polyurethane foam or coatings. (2) Undesirable depositions of airborne spray loss.
OVERSPRAY SURFACE TEXTURE
The surface shows a linear coarse textured pattern and/or a pebbled surface. This surface is generally downwind of the sprayed polyurethane path and is unacceptable for proper coating coverage and protection, if severe.
PARAPET
A wall or top portion of a wall extending above an attached horizontal surface such as a roof, terrace, or deck; often used to provide a safety barrier at a roof edge.
PASS
The amount of coating or polyurethane foam applied by moving the gun from side to side and moving away from fresh material. A pass is delineated by its width, length and thickness. Foam passes sprayed and tied together in one area are called a lift of foam.
PASS LINES
Pass lines are created when the end of a pass of foam or coating ties into an adjacent pass. The overlapping of the polyurethane foam or coating can be seen typically as a darker color than the middle of the pass Foam at the pass lines typically contain thinner lifts than the middle of the foam pass as the applicator tapers the foam to uniformly tie the foam passes together.
PASTE
Typically used in reference to aluminum-based coatings; for aluminum coatings, the amount of aluminum flake typically is less than the amount of paste.
PCF
Pounds per cubic foot or lb/ft3. A measure of density.
PEEL STRENGTH
The average force (or force per unit width) required to peel a membrane or other material from the substrate to which it has been bonded.
PEELING
Top-coating film inadequately bonded with undercoats resulting in partial delamination or detachment of final coat.
PENETRATION
(1) Any object (such as vent pipes, electrical conduit, ducts, structural supports elements, etc.) passing through a roof, wall, floor or other building assembly. (2) Any hole or opening in a building assembly which would allow the passage of air, water or other fluids.
PERM
A unit of water vapor permeance defined as 1 grain of water vapor per square foot per hour per inch of mercury water vapor pressure difference (1 inch of mercury = 0.49 psi). Perm = 1 grain/ft2•hr•in Hg. The SI unit for permeance is ng/s•m2•Pa (1 perm = 57.4 ng/s•m2•Pa).
PERM RATING
The permeance of a material. Breather materials have relatively high perm ratings, vapor retarders have relatively low perm ratings, vapor barriers have essentially zero (negligible) perm ratings. See also: VAPOR RETARDERS.
PERMEABILITY, AIR
The rate at which air will diffuse through a unit area of material induced by a unit differential in air pressure. Air permeability is generally used as a descriptive term and specific values are not usually reported. See PERMEANCE, AIR.
PERMEABILITY, WATER VAPOR
The rate at which water vapor will diffuse through a unit thickness and area of material, induced by a unit differential in water vapor pressure. Permeability values are related to a common thickness and can be used to compare various materials. Units are usually Grains•in/ft2•hr•in Hg or Perm•in. SI unit for permeability is ng/s•m•Pa (1 perm•in = 1.46 ng/s•m•Pa).
PERMEANCE
An index of a material's resistance to water vapor transmission. (See Perm.)
PERMEANCE, AIR
The rate at which air can diffuse or leak through a unit area of material induced by a specific pressure differential (for example 75 Pa or 1.57 lb/ft2). ASTM E 2178 and ASTM E 283 are test methods used to measure air permeance. Units are L/s•m2 (ft3/min•ft2) with pressure reported as Pa (lb/ft2). See also: AIR IMPERMEABLE and AIR PERMEABLE.
PERMEANCE, WATER VAPOR
The rate at which water vapor will diffuse through a unit area of material induced by a unit differential in water vapor pressure. Permeance values are reported for specific thicknesses (usually recommended application thickness). Units are usually Grains/ft2•hr•in Hg or Perm. SI unit for permeance is ng/s•m2•Pa (1 perm = 57.4 ng/s•m2•Pa).
PERSONAL PROTECTIVE EQUIPMENT (PPE)
Includes all protective equipment and supplies designed to protect employees from serious workplace injuries or illnesses resulting from contact with chemical, radiological, physical, electrical, mechanical, or other workplace hazards. Besides face shields, safety glasses, hard hats, and safety shoes, PPE includes a variety of devices and garments such as goggles, coveralls, gloves, vests, earplugs, and respirators.
pH
A measure of acidity/alkalinity of aqueous mixtures. A measure of pH 7 is neutral, lower is more acidic, higher is more alkaline.
PHASED APPLICATION
The installation of a roof system or water proofing system during two or more separate time intervals.
PICTURE FRAMING
Outlining the perimeter of a stud wall cavity with spray polyurethane foam prior to filling the center.
PIGMENT
Finely ground insoluble dispersed particles (powder) which, when dispersed in a coating, may provide, in addition to color, a resistance to UV radiation, better resistance to weathering, hardness, durability, reflectivity and other properties.
PINHOLE
A surface defect in polyurethane foam and/or coating that appears as a small hole as if made by a pin. The term is generally applied to holes caused by expanding gases from solvents, moisture or other volatile compounds or SPF cells open to the surface. See also: BLOWHOLE.
PITCH POCKET
A flange, open-bottomed, metal container placed around columns or other roof penetrations that is filled with hot bitumen or flashing cement to seal a projection.
PLASTIC CEMENT
(See Flashing Cement.)
PLASTICIZER
A substance added to a plastic or coating to increase its flexibility or elongation.
PLY
A layer of felt in a built-up roof membrane system. A four-ply membrane system has four plies of felt.
p-MDI
See POLYMERIC MDI.
POLYISO
See ISOCYANURATE.
POLYMER
A substance consisting of high molecular weight chemical compounds characterized by chains of repeating simpler units.
POLYMERIC MDI (p-MDI)
Isocyanate compounds wherein the molecules contain more than two functional -NCO groups. See also: METHYLENE DIPHENYL DIISOCYANTE.
POLYOL
A high weight molecule that contains hydroxyl groups (-OH), typically at the terminal position on the molecular chain. Polyol is a primary ingredient in the B-side, or resin, of the two-component polyurethane system. After reaction with MDI (A-side), the polyol becomes part of the polyurethane polymer.
POLYURETHANE COATINGS
A one or two part coating that contains polyisocyanate monomer and a hydroxyl containing resin, which react during cure to form polyurethane elastomeric.
POLYURETHANES
Polyol and MDI react to form polyurethane. When this reaction occurs multiple times a polyurethane molecule is created. Many end-use products are created using polyurethane chemistry, including: rigid and flexible foams, rigid or flexible coatings, elastomers, structural materials, etc. (See also AROMATIC, ALIPHATIC, ISOCYANATE, POLYOL, and RESIN)
PONDING
A roof surface that is incompletely drained.
POPCORN SURFACE TEXTURE
The surface exhibits texture of SPF where valleys form sharp angles. This surface is unacceptable for coating application. Also termed treebark surface texture. (See AY-145 Surface Texture of Spray Polyurethane Foam.)
POSITIVE DRAINAGE
The drainage condition in which consideration has been made for all loading deflections of the deck, and additional roof slope has been provided to ensure drainage of the roof area within 48 hours of rainfall.
POST EXPANSION
A characteristic of some single-component SPFs wherein additional expansion occurs after the initial application and froth expansion. Post expansion is due mainly to the chemical curing process.
POT LIFE
The period of time during which a multi-component or catalyzed material remains suitable for application after being mixed.
POUR FOAM
A polyurethane foam system, with a slower reactivity profile (relative to SPF), designed for pouring or injection into confined spaces such as a mold, panel or concrete blocks.
POWERED AIR PURIFYING RESPIRATOR
See RESPIRATOR.
PPE
See PERSONAL PROTECTIVE EQUIPMENT.
PRIMER
The first layer of coating applied to a surface to improve the adhesion of subsequently applied materials or to inhibit corrosion.
PROPELLANT
Liquified or compressed gas formulated into single-component SPF or two-component FROTH PACKS (see also) used to expel the SPF ingredients from its containers. The propellant also functions as a BLOWING AGENT (see also).
PROPORTIONER
The basic pumping unit for spraying polyurethane foam or two component coating systems. Consists of two positive displacement pumps designed to dispense two components at a precisely controlled ratio.
PSI
Pounds per square inch.
PSYCHROMETER
(1) A device for measuring ambient humidity by employing a dry bulb thermometer and a wet bulb thermometer. (2) An electronic device for measuring ambient temperature and humidity.
PSYCHROMETRIC CHART
A diagram relating the properties of humid air with temperature.
PURGE
To cleanse or remove liquid materials from equipment or hoses.
RACKING TEST
Colloquial name for ASTM Standard E72, “Standard Methods of Conducting Strength Tests of Panels for Building Construction.” ASTM E72 tests a stud wall’s resistance to wind, seismic, and weight loads.
RADIANT BARRIERS
Typically in the form of a single highly-reflective sheet or coating (e.g., aluminum foil or metallized mylar) radiant barriers are applied as a component of the building enclosure to inhibit heat transfer by thermal radiation. They do not provide resistance to heat transfer by conduction or convection.
RAKE
The slope edge of a roof at the first or last rafter.
RCI
Roof Consultants Institute.
RECOVERING
The process of installing a new roofing system over an existing roofing system.
RECYCLE CONTENT
The proportion of material (typically percentage by weight) in an end-use product that contains previously used materials. Recycle content can be further classified as "post-industrial" or "post-consumer." The former refers to re-use of by-product materials that are created during the manufacturing process, while the latter refers to waste materials that come from the consumer sector
RE-ENTRANT CORNER
An inside corner of a surface, producing stress concentrations in the roofing or waterproofing membrane.
REFLECTANCE
The fraction of incident radiation (usually the visible spectrum of sunlight) that is scattered (i.e., not absorbed or transmitted) by a surface. Reflectance is expressed as a number between 0 and 1 or as a percentage between 0% and 100%. Cool roofs and reflective coatings have high reflectance values. Also termed REFLECTIVITY.
REFLECTIVE INSULATION
Similar to radiant barriers, reflective insulations are made from multiple sheets of highly reflective film that inhibit heat transfer by radiation. Multiple sheets of the reflective film are formed to create thin air pockets that can reduce heat transfer by conduction and convection in certain applications. Examples of reflective insulation would be a metalized bubble-wrap material or foil panels that unfold or deploy into a sheet with integral air compartments.
REFLECTIVITY
Solar reflectivity (reflectance) is the fraction of the solar energy (flux) that is reflected by the surface; reflectivity is expressed as a percentage or a decimal factor.
REGIET
A groove in a wall or other surface adjoining a roof surface for use in the attachment of counterflashing.
REGLET
(1) An interlocking two-part flashing between a wall or other vertical surface and a roof. (2) A sheet metal clamp or receiver attached to a wall to which a counterflashing may be affixed. (3) A groove in a vertical surface to which a counterflashing may be affixed.
REINFORCED MEMBRANE
A roofing or waterproofing membrane reinforced with felts, mats, fabrics or chopped fibers.
RELATIVE HUMIDITY
The ratio of the weight of moisture in a given volume of air-vapor mixture to the saturated (maximum) weight of water vapor at the same temperature, expressed as a percentage. For example, if the weight of the moist air is 1 pound and if the air could hold 2 pounds of water vapor at a given temperature, the relative humidity (RH) is 50 percent.
RENEWABLE CONTENT
See BIO-CONTENT.
REPLACEMENT
The process of removing an existing roof and installing a new roofing system.
RE-ROOFING
Either recovering or replacement of a roofing system. (See RECOVERING; REPLACEMENT)
RESIDENTIAL ENERGY SERVICES NETWORK (RESNET)
Is a trade association of energy raters (HERS Raters) serving the residential market. This organization provides training and certification to home energy raters. Certified home energy raters must evaluate the entire energy use of a residential building to become EnergyStar certified.
RESIN
1) Component-B in SPF. This component contains a polyol, catalyst, blowing agent, fire retardant, and surfactants. It is mixed with the A component to form polyurethane. 2) General term applied to a wide variety of more or less transparent and fusible products, which may be natural or synthetic. Higher molecular weight synthetic resins are referred to as polymers. 3) Any polymer that is a basic material for coatings and plastics.
RESNET
See RESIDENTIAL ENERGY SERVICES NETWORK.
RESPIRATOR
A device designed to protect the wearer from inhaling harmful dusts, fumes, vapors, and/or gases. Respirators come in a wide range of types and sizes. There are two main categories: (1) the air purifying respirator, which forces contaminated air through a filtering element, and (2) the air-supplied respirator, in which an alternate supply of fresh air is delivered. Within each category, different techniques are employed to reduce or eliminate noxious airborne contaminants.
Some respirators require medical screening and fit testing.
Air Purifying Respirator (APR): Respirators which consist of a facemask and an air-purifying device, which is either attached directly to the mask or carried on a body harness and connected to the mask via a breathing hose. APRs selectively remove specific airborne contaminants (particulate, vapors, fumes, and gases) from ambient air by filtration, adsorption or chemical reactions. Filtering cartridges are removed and replaced at the end of their useful service life. APRs can be either of the full face or half mask varieties.
Powered Air Purifying Respirator (PAPR): A type of air purifying respirator which consist of a powered fan which forces incoming air through one or more filters for delivery to the user for breathing. The fan and filters may be carried by the user or with some units the air is fed to the user via tubing while the fan and filters are remotely mounted.
Supplied Air Respirator (SAR): Often referred to as an airline respirator. These devices provide air to the user, through an airline, from a source located some distance away.
RESPIRATORY PROTECTION PROGRAM
An OSHA requirement whereby any employer who requires or permits employees to wear a respirator must have a written respiratory protection program. The written respirator program establishes standard operating procedures concerning the use and maintenance of respiratory equipment. In addition to having such a written program, the employer must also be able to demonstrate that the program is enforced and updated as necessary. (See CPI Publication AX246 “Model Respiratory Protection Program for Compliance with the Occupational Safety and Health Administration’s Respiratory Protection Program Standard 29 CFR § 1910.134.”)
RETROFIT
The modification of an existing building or facility to include new systems or components.
RIDGING
An upward, tenting displacement of a roof membrane frequently occurring over insulation joints, deck joints and base sheet edges.
ROLL ROOFING
Smooth-surfaced or mineral-surfaced coated felts.
ROOF ASSEMBLY
An assembly of interacting roof components (including the roof deck) designed to weatherproof and, normally, to insulate a building's top surface.
ROOF CURB
Raised frame used to mount mechanic al units such as air conditioning or exhaust fans, skylights, etc.
ROOF SLOPE
The angle of a roof surface measured in the number of inches of vertical rise in a horizontal length of 12 inches.
ROOFING FOAM
Spray polyurethane foam used in exterior roofing applications. Roofing foam nominal core density is typically 40 – 56 kg/m3 (2.5 -3.5 lb/ft3) and compressive strength is typically 280 kPa (40 lb/in2) minimum. Building codes do not limit the smoke development index (per ASTM E 84) for roofing foams; therefore, roofing foams should not be used for interior applications.
RUST BLUSH
The earliest stage of rusting characterized by an orange or red color. Occurs frequently on freshly sandblasted steel if allowed to stand too long before coating.
R-VALUE
The resistance of a material to heat transfer. Insulators have relatively high R values. Units are K•m2/W (F•ft2•hr/Btu).
SADDLE
A relatively small raised substrate or structure constructed to channel or direct surface water to drains or off the roof. A saddle may be located between drains or in a valley, and is often constructed like a small hip roof or like a pyramid with a diamond-shaped base. (See CRICKET)
SAG
Undesirable excessive flow or run in material after application to a sloped or vertical surface.
SAR
Supplied Air Respirator. See RESPIRATOR.
SATURATION HUMIDITY
The maximum concentration of water vapor in air at a given temperature before condensation occurs.
SBCCI
Southern Building Code Congress International. SBCCI, once one of three model code agencies in the US, developed the Southern Building Code which had been commonly adopted in the Southern United States. SBCCI has been absorbed into the ICC (see also).
SCARF
To remove the surface or coating from polyurethane foam by cutting, grinding, or other mechanical means. Synonymous with SCARIFY.
SCARIFY
(See SCARF)
SCRIM
A woven, non-woven, or knitted fabric, composed of continuous strands of material used for reinforcing or strengthening membranes. Scrim may be incorporated into a membrane by the laminating or coating process.
SCUPPER
A woven, non-woven, or knitted fabric, composed of continuous strands of material used for reinforcing or strengthening membranes. Scrim may be incorporated into a membrane by the laminating or coating process.
SCUPPER
An opening in a parapet wall allowing runoff water to exit a roof.
SCUTTLE
A hatch that provides access to the roof from the interior of the building.
SCV
Solid content by volume.
SEAL
(1) a narrow closure strip made of bituminous materials;
(2) to secure a roof from the entry of moisture.
SEALANT
Any of a variety of compounds used to fill and seal joints or openings in wood, metal, masonry and other construction materials. Some common types of sealants are Neoprene®, polysulfide, acrylic latex, butyl, polyurethane, foams and silicone.
SEALANT FOAM
One- or two-component polyurethane foam typically applied as a bead and used to control air leakage as part of an air barrier system within the building envelope. Sealant foams generally have nominal core densities of 8 – 40 kg/m3 (0.5 - 2.5 lb/ft3).
SELF-FLASHING
The ability of sprayed polyurethane foam to be applied around a penetration or at a roof transition without the need for other materials.
SELVAGE
An edge or edging that differs from the main part of (1) a fabric, or (2) granule-surfaced roll roofing material.
SELVAGE JOINT
A lapped joint designed for mineral-surfaced cap sheets. The mineral surfacing is omitted over a small portion of the longitudinal edge of the sheet below in order to obtain better adhesion of the lapped cap sheet surface with the bituminous adhesive.
SERVICE TEMPERATURE LIMITS
The maximum continuous temperature at which a coating, polyurethane foam, or other material will perform satisfactorily.
SET
To convert into a fixed or hardened state by chemical or physical action.
SET OF FOAM
A container of A-side (MDI) and a container of B-side (polyol or resin blend) which can be combined through mixing equipment to form SPF. A set of foam consists of two containers, typically 55-gallon drums.
SHELF LIFE
The period of time within which a material remains suitable for use. Synonymous with STORAGE LIFE.
SHORE HARDNESS
A measure of hardness based on the shore scale.
SILICONE COATING
A liquid-applied, solvent dispersed, elastomeric protective coating whose principal polymer in the dispersion contains more than 95 % silicone resin. Some high solids silicone coatings may have little or no solvent content.
SINGLE-COMPONENT FOAM
A fully formulated foam system packaged in a single aerosol can or pressurized cylinder. Essentially a moisture cure polyurethane prepolymer in a pressurized container. (Also called One Component Foam or OCF.)
SKIN
The dense film portion on the surface of a liquid coating or mastic.
SKINNING
Function of the time necessary to form a dense film on the surface of a liquid coating or mastic to the extent that the material is unaffected by a water spray. The formation of a dense film on the surface of a liquid coating or mastic.
SLIPPAGE
Relative lateral movement of adjacent components of a built-up membrane. It occurs mainly in roofing membranes on a slope, sometimes exposing the lower plies or even the base sheet to the weather.
SLIT SAMPLES
Small cut samples approximately 2” long, ½” wide, and ¾” deep which are taken for evaluation of sprayed materials.
SLOPE
(See Incline.)
SMOKE DEVELOPED
The amount of smoke measured for a sample tested in the ASTM E 84 tunnel test when compared to inorganic reinforced cement board and select-grade red-oak flooring which have been arbitrarily established as zero and 100, respectively.
SMOOTH SURFACE TEXTURE
The surface texture of spray polyurethane foam which exhibits spray undulation and is ideal for receiving a protective coating. Even though the surface texture is classified as smooth, this surface requires at least 5% additional coating material to the theoretical amount. (See AY-145 Surface Texture of Spray Polyurethane Foam.)
SMOOTH-SURFACED ROOF
A built-up roof membrane surfaced with a layer of hot-mopped asphalt, cold-applied asphalt clay emulsion, cold-applied asphalt cutback, or sometimes with an unmopped inorganic felt.
SOLAR REFLECTANCE
The measure of a surface material’s ability to scatter sunlight. COOL ROOFS (see also) and reflective coatings typically have high solar reflectance. Also termed albedo.
SOLAR REFLECTANCE INDEX (SRI)
A calculated index (0 – 100 based on ASTM E 1980) which combines a surface material’s solar reflectance and infrared emittance into a single value. The SRI provides a relative indication of how hot a surface material will become when exposed to sunlight. Cool surfaces have high index values while hot surfaces have low index values.
SOLIDS CONTENT
The percentage of non-volatile matter in a coating or mastic formulation; may be expressed as a volume or weight percent.
SOLVENT
A liquid that dissolves other substances. (See also THINNER)
SOUND TRANSMISSION CLASS (STC)
An integer rating of how well a building partition reduces airborne sound. STC is widely used to rate interior partitions, ceilings/floors, doors, windows and exterior wall configurations.
SPF
Acronym for Spray Polyurethane Foam.
SPF, HIGH PRESSURE
Spray polyurethane foam where the A- and B-components are delivered at a pressure between 1000 and 1300 psi, at a rate up to 30 lb/min wherein the components are atomized and impingement mixed in a spray gun.
SPF, LOW PRESSURE
Spray polyurethane foam where the A- and B- components are delivered a pressure of less than 250 psi, at a rate between 5 and 7 lb/min wherein the components are mixed using a static mixing nozzle. Components are typically delivered in pressurized tanks.
SPFA
Spray Polyurethane Foam Alliance.
SPI
The SOCIETY OF THE PLASTICS INDUSTRY (See also).
SPI / SPFD
The Society of the Plastics Industry / Spray Polyurethane Foam Division. From 1987 to 1999, SPFA was known as SPFD a division of SPI. In 1999 it became an independent trade association, with strong collaborative relationships with the American Chemistry Council’s (ACC’s) Center for the Polyurethanes Industry (CPI), Insulation Contractors Association of America (ICAA) and the National Roofing Contractors Association (NRCA).
SPLIT
A membrane tear resulting from substrate or membrane stress.
SPRAY POLYURETHANE FOAM (SPF)
A foamed plastic material formed by the reaction of an isocyanate and a polyol and employing a blowing agent to develop a cellular structure. SPF may be a two-component reactive system mixed at a spray gun or a single-component system that cures by exposure to moisture. SPF can be formulated to have physical properties (such as density, compressive strength, closed cell content, and R-value) appropriate for the application requirements. Common uses of SPF include insulation, air barrier and roofing membrane.
SPUD
To remove the roofing aggregate and most of the bituminous top coating by scraping and chipping.
SPUDDING
The process of removing the roofing aggregate and most of the bituminous top coating by scraping and chipping.
SQUARE
A standard measurement for roofing area equal to 100 square feet. Also called "roofing square."
SRI
See SOLAR REFLECTANCE INDEX.
STACK EFFECT
Also referred to as "chimney effect," stack effect results from air density differences between building interiors and exteriors. During heating seasons, the stack effect results in higher relative pressures at the tops of buildings and lower relative pressures at the bases of buildings. These pressure differences can drive air infiltration/exfiltration. Proper sealing measures, such as air barriers formed by SPF foam and sealants can mitigate stack effect.
STACK VENT
A vertical outlet in a built-up roof system designed to relieve the pressure exerted by moisture vapor between the roof membrane and the vapor retarder or deck.
STAINING
Temporary or permanent discoloration to the surface of a liquid coating caused by foreign material on the surface.
STC
See SOUND TRANSMISSION CLASS.
STORAGE LIFE
(See SHELF LIFE)
STRESS
An applied force which tends to deform a body. May be tensile stress (pulling or stretching force), compressive stress (pushing or compacting force) or shear stress (opposite but offset parallel forces tending to produce a sliding motion).
STRESS-CRACK
External or internal cracks within a material caused by long term stress.
STRIPPING or STRIP-FLASHING
(1) the technique of sealing a joint between metal and the built-up roof membrane with one or two plies of felt or fabric and hot-applied or cold-applied bitumen;
(2) the technique of taping joints between insulation boards or deck panels.
SUBSTRATE
The surface to which polyurethane foam is applied.
SUBSTRATE
The surface upon which the roofing or waterproofing membrane is applied (i.e., the structural deck or insulation.)
SUMP
An intentional depression around a drain.
SUPPLIED AIR RESPIRATOR (SAR)
See RESPIRATOR.
SURFACE EROSION
The wearing away of a surface due to abrasion, dissolution, or weathering.
SURFACE TEXTURE
The resulting surface from the final pass of SPF. The following terms are used to describe the types of SPF surfaces: smooth, orange peel, coarse orange peel, verge of popcorn, popcorn, treebark, and overspray.
SURFACING
The top layers of a roof covering, specified or designed to protect the underlying roofing from direct exposure to the weather.
SURFACTANT
Short for "surface active agent." Used to alter the surface tension of liquids. An ingredient in polyurethane foam formulations to aid in mixing and controlling cell size.
TACK FREE TIME
The time between the start of mixing the two SPF-forming components and the time that the surface of the foam can be touched with a wooden stick without it sticking
TACK-FREE
A curing phase of polyurethane foam wherein the material is no longer sticky.
TEAR STRENGTH
The maximum force required to tear a specimen, the force acting substantially parallel to the major axis of the test specimen. Values reported as a stress per unit of thickness.
TENSILE STRENGTH
The tensile (pulling or stretching) force necessary to rupture a material sample divided by the sample’s original cross sectional area. Units are usually kPa or psi or lb/in2.
TERMINATION
The treatment or method of anchoring and/or sealing the free edges of the membrane in roofing or waterproofing system.
TEST CUT
A sample of the roof membrane that is cut from a roof membrane to : (a) determine the weight of the average interply bitumen moppings; (b) diagnose the condition of the existing membrane (e.g., to detect leaks or blisters).
THERMAL BARRIER
A material applied over spray polyurethane foam (and other foam plastics) designed to slow the temperature rise of the foam during a fire situation and delay its involvement in the fire. With few exceptions, building codes require that SPF be separated from interior spaces with a thermal barrier. Building codes require that thermal barriers for use with polyurethane foam: (1) limit the average temperature rise of the unexposed foam surface to no more than 139°C (250°F) after 15 minutes of fire exposure complying with ASTM E 119 or UL 263 standard time-temperature curve; and (2) will remain in place for 15 minutes based on a small room corner test.
THERMAL BRIDGE
A thermally conductive material which penetrates or bypasses an insulation system such as a metal fastener or stud.
THERMAL CONDUCTANCE C
A unit of heat flow that is used for a specific thickness of material or for materials of composite construction, such as laminated insulation. C=k/thickness. Units are W/m2•K (Btu/hr•ft2•F).
THERMAL CONDUCTIVITY (k)
The heat energy that will be transmitted by conduction through 1 square foot of 1 inch thick homogeneous material in one hour when there is a difference of 1 degree Fahrenheit perpendicularly across the two surfaces of the material. Units are W/m•K (Btu•in/hr•ft2•F).
THERMAL INSULATION
A material applied to reduce the flow of heat.
THERMAL MOVEMENT
Changes in dimension of a material as a result of temperature changes.
THERMAL RESISTANCE R
An index of a material’s resistance to heat flow; it is the reciprocal of thermal conductance (C) or the thickness divided by THERMAL CONDUCTIVITY (k) (see also). See also: R-VALUE.
THERMAL SHOCK
The stress producing phenomenon resulting from sudden temperature drops in a roof membrane, for example, a rain shower following brilliant sunshine.
THERMOGRAPHY
A technique used to locate wet areas in a roof assembly by measuring differences in temperature.
THERMOPLASTIC
A polymer that softens and/or melts when heated. Polystyrene is an example of a thermoplastic material.
THERMOSET
A polymer that irreversibly cures to its finished state through a catalytic reaction. Unlike thermoplastic foam, a thermoset foam cannot be melted. Polyurethane spray foam and polyisocyanurate board foam are examples of thermoset materials.
THINNER
A liquid used to reduce the viscosity of coatings or mastics. Thinners evaporate during the curing process. Thinners may be used as solvents for clean up of equipment.
THIXOTROPIC
Having the property of decreasing viscosity with increasing shear stress. A coating is thixotropic if it thins with stirring or pumping but thickens back up when movement ceases.
THIXOTROPY
The sag resistance or the ability of a coating to “hang on” to a sloped surface.
THROUGH-WALL FLASHING
A water-resistant membrane or material assembly extending through a wall and its cavities, positioned to direct water entering the top of the wall to the exterior.
TIE-IN LINES
The starting or stopping point at which new foam is applied to foam which had been sprayed earlier.
TINT
A color produced by the introduction of small amounts of a colored pigment.
TOXICITY
The quality, property, or degree of being poisonous or toxic.
TRANSITION MATERIAL
A material (typically a tape or membrane) or combinations of materials used between adjacent building envelope components to provide continuity for an air barrier or water resistive barrier assembly.
TREEBARK SURFACT TEXTURE
See POPCORN SURFACE TEXTURE.
TUCK POINTING
(1) troweling mortar into a joint after masonry units are laid;
(2) final treatment of joints in cut stonework. Mortar or a putty-like filler is forced into the joint after the stone is set.
TWO-COMPONENT SYSTEM
A coating or polyurethane foam formed by the mixing and the reaction of two different materials.
TWO-PART SYSTEM
See TWO-COMPONENT SYSTEM.
UBC
Uniform Building Code. A model code promulgated by the ICBO (see also). The UBC has largely been displaced by the I-CODES (see also).
U-FACTOR
The U-factor, or thermal transmittance, is a measure of the thermal conductivity for a building enclosure assembly (e.g., wall, floor, ceiling, roof) or a building component (e.g., window, door). Incorporating parallel and series conductive heat transfer principles and the R-value or thermal conductivities of each component in the assembly, the U-factor can be calculated. The U-factor, when multiplied by the surface area and the indoor-outdoor temperature difference, predicts the amount of heat loss through the assembly, which means assemblies with low U-factor are more energy efficient. U-factors are typically expressed as (Btu/hr•ft2•F) or (W/m2•C).
UFFI
See UREA-FORMALDEHYDE INSULATION.
UL
Underwriter’s Laboratory. An independent testing agency.
ULTRA-VIOLET RADIATION (UV)
Electro-magnetic radiation beyond the visible spectrum at its violet end. Invisible high-energy sunlight which degrades many organic materials.
UNDERLAYMENT
A material that is laid down as a substrate for the sprayed polyurethane foam to make the surface smooth or to give a specific rating for interior fire exposures.
UNDERWRITERS LABORATORY AND WARNOCK HERSEY
Organizations that test and classify consumer products such as roof assemblies to methods defined by objective forums like ASTM.
UPLIFT
(See WIND UPLIFT)
UREA-FORMALDEHYDE FOAM INSULATION (UFFI)
Urea-formaldehyde foam insulation was developed as an improved means of insulating difficult-to-reach cavities in house walls. It is typically made at a construction site from a mixture of urea-formaldehyde resin, a foaming agent and compressed air. When the mixture is injected into the wall, urea and formaldehyde unite and "cure" into an insulating foam plastic. The chemistry of UFFI and SPF are very different, as SPF contains no added formaldehyde.
UV
An abbreviation for ultraviolet. (See also ULTRAVIOLET RADIATION)
VAPOR BARRIER
(1) A membrane, coating or other material that has very low water vapor transmission rates. (2) A component within a building assembly used to limit the transmission of water vapor by diffusion. Comment: The term vapor barrier is imprecise and the term VAPOR RETARDER (see also) is generally preferred.
VAPOR MIGRATION
The movement of water vapor from a region of high vapor pressure to a region of lower vapor pressure.
VAPOR PRESSURE
The portion of atmospheric pressure contributed by water vapor; an indicator of absolute humidity. Units are kPa (in Hg).
VAPOR RETARDER
A vapor retarder is a component of the building enclosure used to control moisture diffusion through the component or assembly. It is generally placed at the warm side of the enclosure assembly to control condensation. In terms of the International Model Building Codes, there are three classes of vapor retarders used in building enclosures, categorized as follows, based on the measured water vapor transmission per ASTM E 96 dry-cup or dessicant method A:
• Class I: less than 0.1 perms
• Class II: greater than 0.1 perms but less than or equal to 1.0 perms
• Class III: greater than 1.0 perms but less than or equal to 10 perms.
Class II vapor retarders are generally required in colder climates – check with the local building code. Examples of Class II vapor retarders include asphalt-kraft facings, ~2 inches of medium-density SPF. Examples of Class I vapor retarders would be a 6 mil PE sheet.
VENT
An opening designed to convey water vapor or other gas from inside a building or a building component to the atmosphere, thereby relieving vapor pressure.
VERGE OF POPCORN SURFACE TEXTURE
The verge of popcorn surface is the roughest texture suitable for receiving the protective coating. The surface shows a texture where nodules are larger than valleys, with the valleys relatively curved. The surface is considered undesirable due to the additional amount of coating required to protect the surface. This surface requires at least 50% additional material to the theoretical amount. (See AY-145 Surface Texture of Spray Polyurethane Foam.)
VISCOSITY
The thickness or resistance to flow of a liquid. Viscosity generally decreases as temperature increases.
VISCOSITY
The measure of flow resistance of a fluid at a specific temperature and pressure; as viscosity increases, flow rate decreases.
VOC
See VOLATILE ORGANIC COMPOUNDS.
VOLATILE ORGANIC COMPOUNDS
Generally carbon-containing compounds that have sufficient vapor pressure to be present as a gas or vapor at room temperatures. The EPA specifically defines regulated VOCs in 40 CFR51.100s. In the U.S,, closed-cell SPF systems generally contain fluorocarbon blowing agents (HFC, HCFC or CFC) that are not classified as VOCs by the US EPA.
WALKWAYS
High traffic and high service areas on a rooftop, particularly those with vents, hatches, and heavy duty air conditioning units, that have been reinforced with extra coating and granules to prevent damage to the polyurethane foam system.
WATER ABSORPTION
The percent increase in weight of a specimen after immersion in water for a specified time. For SPFs, water absorption is reported as volume percent in accordance with ASTM D 2842.
WATER CUTOFF
(See Cutoff.)
WATER RESISTANT BARRIER (WRB)
Materials or combination of materials which are primarily designed to be used to keep liquid water from entering the building enclosure. Water resistive barriers are combined with flashing and other materials to ensure that there is a shingled assembly to direct liquid water which passes on the cladding system to be directed to the exterior. Also known as weather resistive barrier.
WATER VAPOR PERMEABILITY
See PERMEABILITY, WATER VAPOR.
WATER VAPOR PERMEANCE
See PERMEANCE, WATER VAPOR.
WATER VAPOR TRANSMISSION
The migration of water vapor.
WATER VAPOR TRANSMISSION RATE
The rate at which water vapor will diffuse through a unit area of material. Units are usually grains/ft2•hr.
WATER-BLOWN FOAM
A spray polyurethane foam (SPF) formulation of any density which uses water as the predominant (reactive) blowing agent.
WATERPROOFING
Treatment of a surface or structure to prevent the passage of water under hydrostatic pressure.
WEATHER RESISTIVE BARRIER
See WATER RESISTANT BARRIER.
WEATHEROMETER
An artificial weathering device that uses a light source for ultraviolet testing.
WET BULB TEMPERATURE
The temperature of air as registered by a thermometer whose bulb is covered by a water wetted wick. Units are °C or °F.
WET FILM GAUGE
A gauge for measuring the thickness of wet coating as applied to a flat smooth surface.
WET FILM THICKNESS
The thickness, expressed in mm or mils, of a coating or mastic as applied but not cured. (For comparison, see DRY FILM THICKNESS) (See also: MIL)
WET-OUT
The ability for a coating to flow to a thin film when coming in contact with a surface or another cured coating without displaying any visible anomalies such as beading or improper film formation.
WIND UPLIFT
The force caused by the obstructions causing a drop in air pressure deflection of wind at roof edges, roof peaks, or immediately above the roof surface.
WINDSCREEN
A device to minimize the effects of wind on coating or polyurethane foam application.
WRB
See WATER RESISTANT BARRIER.
WUFI
A computer-based, one-dimensional model to simulate transient heat and moisture transfer through building assemblies, developed by the Fraunhofer Institute in Holtzkirchen, Germany. WUFI can be used to predict condensation, moisture accumulation and mold growth potential in building assemblies. WUFI is an acronym for the German phrase Wärme Und Feuchte Instationär (translation: Transient Heat and Moisture).
