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Glossary of Terms
ABATEMENT: See Asbestos Abatement.
ABRASION RESISTANCE: The ability of a material to withstand abrasion without wearing away.
ABSORPTION: The property of a material to assimilate liquids through its structure; sound: that property of a material that converts sound energy into heat energy, generally expressed as the materials' sound absorption coefficients or noise reduction coefficients (NRC).
ABUSE COVERINGS AND FINISHES: Jackets or mastics used to protect insulation from mechanical and personnel abuse.
ACIDITY: The quality of a material to be acidic (pH under 7) when exposed to moisture or water producing a red/pink reaction to litmus paper. In the insulation industry, materials with pH between6 and 8 are generally considered non-acidic and non-alkaline.
ACOUSTICAL TREATMENT: Application of absorbing insulation for sound control.
ACRYLONITRILE-BUTADIENE-STYRENE (ABS): A high-impact plastic.
ADDITIVE: Any substance that is added to a resin, usually in a relatively small percentage, to alter properties. Examples are slip additives, pigments, stabilizers and flame retardants.
ADHESIVE: A substance used to bond materials by surface attachment.
ADHESIVE: A material capable of bonding one surface to another. Adhesives are used in the plastics industry to join a plastic article to another article of (a) the same plastic, (b) a different plastic, or (c) a non-plastic material.
AIR CONDITIONED SPACE: Building area supplied with cooled conditioned air.
AIR CONDITIONING: See Conditioned Air. Top of Page
ALIPHATIC: An organic substance containing straight or branched chain arrangements of carbon atoms.
ALKALINITY: The quality of a material to be basic or alkaline when exposed to moisture or water producing a blue reaction to litmus paper. A pH over 7. In the insulation industry, materials with pH between6 and 8 are generally considered non-acidic and non-alkaline.
AMBIENT TEMPERATURE: The average temperature of the medium, usually air, surrounding the object under consideration.
AMBIENT: (adj.) Surrounding -- encompassing (Generally applied to temperature, humidity and atmospheric conditions).
ANNULAR SPACE (ANNULUS): The distance between a penetrating item and the surrounding opening.
ANTI-ABRASIVE COATING: Cushioning material applied where insulation contacts the pipe, duct, vessel, or adjacent insulation to prevent eroding of either or both.
ANTI-SWEAT: Any application that prevents condensation.
APPEARANCE: Important in exposed areas and for coding purposes.
APPEARANCE COVERING: Materials used to improve the aesthetics of the finished insulation.
APPLICATION TEMPERATURE LIMITS: Minimum and maximum temperatures between which it is usually safe to apply finishes, adhesives and sealants without endangering the integrity of the material.
AROMATIC: A class of organic compounds containing a resonant, unsaturated ring of carbon atoms. Included are benzene, naphthalene, anthracene and their derivatives.
ASBESTOS ABATEMENT: A procedure for the removal, enclosure or encapsulation of asbestos containing materials from buildings or areas.
ASJ: All service jacket.
ASPHALT CUTBACK: Petroleum asphalt in mineral solvents. (This is a vapor-retarder mastic.)
ASPHALT EMULSION: A colloidal dispersion of petroleum asphalt in water. (This is a breather mastic.)
ASTM: American Society for Testing and Materials. An independent association which has accepted responsibility for the development and administration of voluntary standards for the testing and evaluation of a wide range of products.
ATTENUATION: The limiting of sound propagation from one area to another.
BANDS: Strapping used to fasten insulation and/or jacketing in place.
BASIC: See Alkalinity.
BATT: A piece of flexible type insulation of specified width and length with or without vapor retarder jacket.
BEADING: Process of curling the edge of jacketing to accommodate sealing.
BEDDING COMPOUND: A plastic material (mastic) used to imbed insulation. Acts as a cushion, anti-abrasive and adhesive.
BENDS (Tube Turns): Pipe, factory or field formed, to a predetermined radii.
BINDER: Substance contained in insulation material which stabilizes the fibers.
BLANKET: Flexible fibrous insulation in sheet or roll form with or without facing.
BLEEDING: The diffusion of coloring through a coating from its base or substrate (such as bleeding of asphalt mastic through a paint top coat).
BLISTER: Rounded elevation of the surface of a mastic resembling a blister on the human skin, usually the entrapment of air or vapor.
BLOCK: Rigid or semi-rigid, insulation formed into rectangular or curved shapes.
BLOWING AGENT: A substance incorporated in a mixture for the purpose of producing foam. For polyurethanes, this is usually either carbon dioxide generated from the diisocyanate/water reaction or introduced as liquid CO2 or a low boiling hydrocarbon liquid (such as pentane) volatilized by the heat of the polyurethane-forming reactions.
BOARD: Rigid or semi-rigid self-supporting insulation formed into rectangular or curved shapes.
BOCA: Building Officials and Code Administrators.
BODY: The viscosity or consistency of a mastic or coating.
BOND STRENGTH: The force in tension, compression, cleavage or shear required to break an adhesive assembly.
BONDING TIME: The time required for an adhesive to reach its optimum bonding strength.
BOX TRENCH: Built-up enclosure either in a shallow trench or buried underground.
BRANCH: Distribution piping or ductwork, same as a main except, smaller and from or returning to the main, serving two or more runouts. See Table 12.11, 12.12, & 12.13.
BREAKING LOAD: In some installations the insulation material must "bridge" over a discontinuity in its support. The Breaking Load is the force necessary to create structural failure in a "bridging" condition. See Flexural Strength.
BREATHER COATING: A weather barrier coating designed to prevent water (rain, snow, sleet, spillage, wash water, etc.) from entering the insulation system, while still allowing the escape of small quantities of water vapor resulting from heat applied to the moisture entrapped in the insulation.
BRITISH THERMAL UNIT (BTU): The amount of heat required to raise one pound of water one degree Fahrenheit at 59F., specifically 778.26 ft. lbs.
BUILT-UP ROOF: A composition roof composed of layers of roofing felt mopped with hot asphalt and usually topped with gravel.
BUTT JOINTS: The end joints of pipe insulation.
BUTT STRIP: Strips of similar jacket material applied around pipe insulation butt joints.
"C" VALUE (Thermal Conductance): A measure of the rate of heat flow for the actual thickness of a material. If the "K" of a material is known, the "C" can be determined by dividing the "K" by the thickness. The lower the "C", the higher the insulating value. CALCIUM SILICATE: A hard granular molded insulation manufactured from a hydraulic cured mixture of calcium, silicate, water and inorganic binders.
CANVAS: A plain weave cotton fabric used for jacketing.
CAPILLARITY (Insulation): The ability of a cellular, fibrous or granular material to diffuse water into its structure. A wick-like action whereby a liquid will migrate vertically through material in a upward direction. The movement of the liquid material against gravity is the result of surface tension.
CATALYST: A substance that causes or accelerates a chemical reaction when added to the reactants in a minor amount, and that is not consumed in the reaction.
CAULK: To seal and make water and/or air tight. Top of Page
CELLULAR GLASS: Glass insulation produced by chemically and thermally expanding a glass material into a rigid closed cell form.
CELLULAR INSULATION: Insulation composed of small individual cells separated from each other. The cellular material may be glass, elastomeric or plastic such as polystyrene (closed cell) or polyurethane.
CELLULAR PLASTIC: Plastic expanded by thermal or chemical means, containing closed cells throughout.
CERAMIC FIBERS: Pure silica heated and expanded to produce fibers from which high temperature insulation can be made.
CHALKING: A soft white or gray appearance on the surface of a weathered finish.
CHECKING: Failure of a coated surface characterized by the appearance of fine cracks in all directions.
CHEMICAL RESISTANCE: Capability of a material to withstand exposure to acids, alkalis, salts, and their solutions.
CHICKEN WIRE: Hexagonal wire netting (poultry mesh) used as reinforcement.
CLADDING-JACKETING: Jacketing installed over insulation.
CLEARANCE: Adequate space allowed for installation of insulation materials.
COATING: A liquid or semi-liquid protective finish capable of application to thermal insulation or other surfaces usually by brush or spray in moderate thickness, less than 30 mils. (0.030"). Top of Page
CODE (Building): A set of construction and material standards, usually statutory. Model building codes are adopted by each municipality from the major code organizations. The major code authorities are B.O.C.A., (Building Officials and Code Administrators) (primarily Midwest), I.C.B.O. (International Council of Building Code Officials), (west and Indiana), S.B.C.C.I. (Southern Building Code Congress, International (south). The local municipality or state can choose which major building code is adopted.
COEFFICIENT OF EXPANSION/CONTRACTION: The change in a unit length of a material corresponding to a unit change in the temperature of the material.
COMBUSTIBLE: Capable of burning.
COMPACTION RESISTANCE: That property of a fibrous or loose fill material which resists compaction under load or vibratory conditions.
COMPATIBLE MATERIALS: Two or more substances which can be mixed or used together without separating, reacting, or adversely affecting the materials.
COMPRESSIVE STRENGTH: That property of an insulation material which resists any change in dimensions when acted upon by a compaction force.
CONCEALED SPACES: Spaces not generally visible after the project is completed such as furred spaces, pipe spaces, pipe and duct shafts, spaces above ceilings, unfinished spaces, crawl spaces, attics and tunnels.
CONDENSATE DRAIN: Piping carrying condensed water from air conditioning or refrigeration drip pans to a point of discharge.
CONDENSATE RETURN: The liquid formed by condensation of vapor. In steam heating it is water condensed from steam. In air conditioning it is the water extracted from the air by cooling. Top of Page
CONDENSATION: The act of water vapor turning into liquid upon contact with a cold surface.
CONDITIONED AIR: Air treated to control simultaneously its temperature, humidity and cleanliness to meet the requirements of a conditioned space. (May be cool and/or heated and should be clearly defined.)
CONDUCTANCE (THERMAL) "C": The rate of heat flow for the actual thickness of a material.
CONDUCTIVITY (THERMAL) "K": The rate of heat flow based on 25 mm (one inch) thickness.
CONDUCTION: The transfer of heat energy within a body or between two bodies in physical contact.
CONTACT ADHESIVE: An adhesive which when dry to the touch will adhere to itself instantaneously on contact.
CONVECTION: The transfer of heat by movement of fluids.
CORROSION: Deterioration by chemical action.
COUPLINGS: Screwed, soldered, welded or mechanical/grooved connections between links of pipe.
COVER (v.): To place insulation and/or finish materials on, over or around a surface so as to insulate, protect, or seal.
COVERAGE: The rate in square feet per gallon (coatings), or gallons per hundred square feet (mastics), at which products must be applied to obtain satisfactory performance.
CRIMPING (v.): Corrugating of the metal edge to reduce diameter or facilitate bending. Used on fitting gores to mate with beaded edge of adjacent segment or on end caps for tanks and vessels. Top of Page
CRYOGENIC INSULATION: Insulation for extremely low temperature surfaces from -73.3C to -273.2C (-100F to -459F) (absolute zero).
CUPPED HEAD PIN: Capacitor discharge welded insulation fastener with a fixed washer.
CURE: To change the properties of a plastic or resin by chemical reaction, usually accomplished by the action of either heat or a catalyst.
DAMMING: The use of a substance to support firestopping materials until cured.
DECIBEL (dB): A logarithmic measure of the ratio of like power quantities as used in describing levels of sound pressure or sound power.
DECOMPOSITION: The separating or breaking down of a substance into its component parts or basic elements.
DELAMINATION: The separation of the layers of material in a laminate.
DENSITY: The weight per unit volume of a substance.
DEW POINT: Saturation temperature where water vapor and liquid occur simultaneously.
DIFFUSIVITY: The time rate of temperature change within a body, or between two of its surfaces.
DIMENSIONAL STABILITY: That property of a material which enables it to maintain its original size, shape and dimensions.
DRY (v.): To change the physical state of a substance by the loss of solvent constituents by evaporation, absorption, oxidation, or a combination of these factors. Top of Page
DUAL TEMPERATURE: Systems of equipment which operate as cold and/or hot systems.
DUCT FLANGE (Stiffener): A structural or fabricated angle iron shape, attached to the exterior surfaces of a duct at specified intervals for the purpose of reinforcing the metal and assembly of the ducts.
DUCT: A passageway made of sheet metal or other suitable material used for conveying air or other gas.
EFFLORESCENCE: A white powdery substance occurring on the surface of coated insulation products caused by the migration of soluble salts from the insulation, followed by precipitation and carbonation.
ELASTOMER: A material that at room temperature can be stretched repeatedly to at least twice its original length and, immediately upon release of the stress, return with force to its approximate original length. This definition is one criterion by which materials called plastics in commerce are distinguished from elastomers and rubbers.
ELASTOMERIC: A foamed insulation containing elastomers that provide the property of high elasticity.
EMISSIVITY (E): The ability of a surface to radiate energy as compared to that emitted by an ideal black body at the same temperature.
EMULSION: Insoluble fine solids or liquids dispersed in another liquid, usually water.
EPOXY RESINS: A two-part compound of an epoxy and catalyst which cures at ambient temperatures to form finishes which are highly resistant to solvents and chemicals. A high bond adhesive.
EXHAUST DUCT: A duct carrying air from a conditioned space to an outlet outside the building.
EXPANDED METAL LATH: See Lath -- expanded metal.
EXPANDED POLYSTYRENE (EPS): Expanded polystyrene, manufactured from styrene, is a closed-cell, thermoplastic material often molded into low-density foam articles, such as protective packaging, foam insulation and building and construction.
EXPOSED SPACES: Those spaces not referred to as concealed or as defined by the specifier.