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Glossary of Terms
"F" RATING: A rating usually expressed in hours indicating a specific length of time that a fire-resistive barrier can withstand fire before being consumed or permits the passage of flame through an opening in the assembly.
F.D.A. APPROVAL: Compliance with the Food and Drug Administration's regulations for food handling operations.
FACING: A thin layer or laminate, usually factory applied, on the surface of an insulating material.
FAN: A mechanical air-moving device.
FIBER GLASS: A composite material consisting of glass fibers with a resin binder.
FIBROUS INSULATION: Insulation composed of small diameter fibers which finely divide the air space. Fibers used are silica, rock wool, slag wool or alumina silica.
FILM (WET): The applied layer of mastic or coating before curing or drying.
FINISHING CEMENT: A mixture of various insulating fibers, fillers and binders with water, with or without hydraulic cement, to form a smooth trowelable paste insulation for application over insulating cement or unfinished block insulation.
FIRE RESISTANCE: The property of a material or assembly to withstand fire or give protection. It is characterized by the ability to confine a fire and to continue to perform a given structural function. Top of Page
FIRE RETARDANCE (FR): That property of a material which retards the spread of fire. Flame spread and smoke developed ratings are particularly important for indoors installations. Check national and local codes for building requirements.
FIRESTOPPING: Shall consist of furnishing and installing a material or a combination of materials to form and effective barrier against the spread of flame, smoke, gases and moisture. It is to maintain the integrity of the fire-rated construction.
FISH-MOUTH: A gap between layers of sheet materials caused by warping or bunching of one or both layers.
FITTING COVER: The insulation for a pipe fitting composed of the specified thickness of insulation material which may be preformed. Also a preformed jacketing.
FITTINGS: Items used to change size, direction of flow, level or assembly of piping, except for unions, grooved couplings, flanges, valves or strainers.
FIXTURE CONNECTION: Final piping connections to plumbing fixtures (usually exposed and chrome plated).
FLAME RETARDANT: The quality of a material to limit the flame spread across its surface.
FLAME SPREAD: The rate expressed in distance and time at which a material will propagate flame on its surface.
flame.
FLANGE COVER: The insulation for a pipe flange composed of the specified thickness of insulation material, may be preformed. Also a preformed jacketing.
FLANGE: A projecting collar attached to a pipe for the purpose of connecting to another pipe, valve or fitting. Top of Page
FLASH POINT: The temperature at which combustion is initiated.
FLASHING: The arrangement of metal or other weather barrier finishes to prevent penetration of water or other substances at a junction of two planes.
FLEXIBILITY: That property of a material which allows it to be bent (flexed) without loss of strength.
FLEXURAL MODULUS: Ratio of maximum fiber stress to maximum strain, within elastic limit of the stress-strain diagram obtained in the flexure test. The flexural modulus is a measure of elasticity, or the ability for the material to be deformed and return to its original shape. An alternate term is the Flexural Modulus of Elasticity.
FLEXURAL STRENGTH: The flexural strength of a material is its ability to resist deformation under load, or how much you can bend the material before it starts to break. For materials that do not break, the load at yield, typically measured at 5% deformation/strain of the outer surface, is reported as the flexural strength or flexural yield strength. The general term for bending stiffness is flexural rigidity, which is the product of the material's elastic modulus and the cross section moment of inertia.
FOAMED PLASTIC: Plastic expanded by thermal or chemical means, containing closed cells throughout.
FREEZE/THAW STABILITY: The property of a product which allows it to be subjected to temperatures below freezing and still be usable when returned to room temperature.
FRESH AIR DUCT (Make-up Air): A duct used to convey outdoor air to a point within the building, terminating at the mixing plenum, air handling unit, or discharge grill.
FRESH AIR: Air taken from outdoors.
FRIABILITY: The characteristic of a material to lose mass as a result of a combination of abrasion and impact produced by a laboratory tumbling mechanism.shed particles. Insulation friability is of concern during handling and insulation, since insulation with higher friability can abrade unprotected hands and raise dust that can irritate lungs. Dyplast's polyisocyanurate and expanded polystyrene have excellent friability characteristics. Friability of preformed block-type thermal insulation is measured per ASTM C421.
FSK: Foil scrim kraft.
FUEL CONTRIBUTION: Combustible byproducts from a substance generated or emitted in a burning environment.
GALVANIC CORROSION (Electrolysis): Effect of two dissimilar metals in the presence of an electrolyte to produce a weak voltaic cell causing deplating or pitting of the more soluble metal. Top of Page
GLASS CLOTH: Closed weave glass fiber used as a finish jacket.
GLASS FABRIC: Open weave glass fiber used as a reinforcing membrane.
GLASS FIBER: A composite material consisting of glass fibers with a resin binder.
GORE: Curved segment of a finish jacket used for elbows, tank heads or other curved surfaces.
GRANULAR INSULATION: Insulation composed of small nodules which contain voids or hollow spaces. The material may be calcium silicate, diatomaceous earth, expanded vermiculite, perlite or cellulose.
HANDICAPPED FIXTURES: Exposed fixture connections located in facilities for the handicapped. Waste and hot piping exposed connections in these areas are usually insulated for personnel protection.
HANGER (Pipe): Devices used to support piping.
HEATED SPACE: Building area supplied directly with heat.
HEEL: The outside radius of an elbow.
HERTZ (Hz): A measurement of sound frequency measured in cycles per second.
HIGH PRESSURE CONDENSATE: That condensate directly received from high pressure steam lines.
HIGH PRESSURE STEAM: Steam at or above 75 pounds per square inch gauge.
HIGH RIB LATH: A metal lath with a built-in rib used to provide air space under insulation applications. Top of Page
HIGH VELOCITY DUCT: A duct designed with air flow at over 2000 feet per minute velocity with a static pressure exceeding 6 inches.
HORIZONTAL PIPING: Any piping up to and including 45 degree from the horizontal plane.
HOUSINGS (Built-up): Assembled or fabricated at the construction site.
HOUSINGS (Casings): Enclosures of sheet metal or other material to house fans, coils, filters or other components of air handling equipment.
HUBS: Caulking or cement connections between pipe joints.
HUMIDITY: A measure of the amount of water vapor in the atmosphere.
HYGROSCOPICITY: Tendency of a material to absorb water vapor from the air. Especially pertinent for materials whose physical characteristics are altered by effects of water vapor.
ICBO: International Council of Building Code Officials.
IMPACT RESISTANCE: Capability of an insulation material and/or finish to withstand mechanical or physical abuse.
IMPALE: To pierce or fix by piercing on a sharp point.
INSULATE: To cover with a material of low conductivity in order to reduce the passage or leakage of heat.
INSULATING CEMENT: A mixture of various insulating fibers and binders with water to form a moldable paste insulation for application to fittings, irregular surfaces or voids.
INSULATION HANGER: A device such as a welded pin, stud or adhesive secured fastener which carries the weight of insulation.
INSULATION: Those materials or combination of materials which retard the flow of heat.
INTUMESCENT: A characteristic of certain firestop products that when exposed to heat, expand to seal and fill any void in the penetration. When exposed to fire, intumescent products will form a hard char.
ISOCYANATE: A compound containing the isocyanate group, -N=C=O, attached to an organic radical or hydrogen.
JACKET: A covering placed over insulation for various functions.
JOINT: The place where two adjacent pieces of material or jacketing meet. They may be overlapped, sealed, filled (pointed) or finished by the application of tape, cement, mastic, coatings, additional layer of insulation materials or other compounds.
"K" (Conductivity): The measure of heat in BTU's that pass through one square foot of a homogeneous substance 1" thick, in an hour for each degree temperature difference. The lower the "K", the higher the insulating value. Also expressed in watts/meter kelvin.
LACING: A method of joining or securing insulation materials, reinforcements,
LAG (v.): To apply lagging. (n.) A single piece of lagging material.
LAGGING - INSULATION: A block material for insulating tanks and boilers, usually curved or tapered and can be made from any of several insulation materials.
LAGGING - JACKETING: Jacketing installed over insulation. Top of Page
LAGGING ADHESIVE: Water based resin emulsion products that are used to adhere lagging cloth to the insulation and to itself at the lap joints. They also seal and size the fabric and shrink it tightly to the surface. They can be brushed or sprayed.
LAMINATE (n.): A product made by bonding together two or more layers of material or materials.
LAP ADHESIVE: The adhesive used to seal the butt joints and laps of insulation jackets.
LATH - EXPANDED METAL: A lattice type of material of various gauges and sizes, used to provide reinforcement for insulation materials.
LATH - HIGH RIB: A metal lath with a built-in rib used to provide air space under insulation applications.
LOG MEAN (Radius): The equivalent value of insulation thickness for pipe (curved surfaces) to produce the same resistance to heat flow as per flat areas.
LOOSE OR FILL INSULATION: Insulation consisting of loose granules, fibers, beads, flakes, etc., which must be contained and are usually placed in cavities.
LOW PRESSURE CONDENSATE: That condensate directly received from low pressure steam.
LOW PRESSURE STEAM: Steam at or below 15 pounds per square inch gauge.
LOW VELOCITY DUCT: A duct designed with air flow at not more than 2000 feet per minute velocity with static pressure not above 2 inches. Top of Page
MAIN: Piping or ductwork from a source to the last branch connection or from the last branch connection returning to the source or to a termination point. See Tables 12.11, 12.12 and 12.13.
MASTIC: A protective coating, usually a petroleum or other base product, applied by spray or trowel to weatherproof or otherwise prevent deterioration of the insulation to which it is applied.
MAT: A piece of insulation of the semi-flexible type, composed of fibers of one or more kinds in which the fibers are in random arrangement, used to support another material.
MDI: An abbreviation for 4,4’ diphenylmethane diisocyanate.
MEAN TEMPERATURE: Operating temperature plus ambient divided by 2. (Thermal Conductivity charts are calculated to use mean temperatures.)
MECHANICAL COUPLINGS: Bolting devices used in assembly of piping.
MEDIUM PRESSURE CONDENSATE: That condensate directly received from medium pressure steam.
MEDIUM PRESSURE STEAM: Steam under 75 pounds per square inch gauge, but above 15 pounds psig.
MEDIUM VELOCITY DUCT: A duct designed with air flow over 2000 feet per minute velocity with a static pressure below 6 inches.
MEMBRANE REINFORCEMENT: Woven or non-woven fabrics used for saturation and embedment in mastic and coating applications to provide strength, continuity and impact resistance. See Glass Fabric. Top of Page
METRIC PERM: Perm measured at 23C Kilogram per Pascal Second square meter [kg/Pa-s-m2]
MINERAL WOOL (Fiber): A generic term which applies to all types of inorganic fibrous insulations.
MIXED AIR DUCT (Plenum): A duct or plenum located at a point where air returned from a space inside the building, and fresh air are mixed or metered by dampers for redistribution through the air handling unit.
MOISTURE BARRIER: A coating or laminate on the inner surface of metal jacketing.
MOLD AND MILDEW RESISTANCE: That property of a material which enables it to resist the formation of fungus growth.
NFPA: National Fire Protection Association.
NOISE REDUCTION COEFFICIENT (NRC): A single number rating that is the arithmetic average of the individual sound absorption coefficients at 250, 500, 1000 and 2000 Hz to the nearest .05.
NONCOMBUSTIBLE: A material which will not contribute fuel or heat to a fire to which it is exposed.
NONFLAMMABLE: A material which will not release heat when exposed to fire or flame.