The reduction or elimination of a substance or intrusion such as lead, asbestos, or noise.

Abrasion Resistance

The ability of a material to withstand abrasion without showing signs of erosion.

Absolute Zero

The point at which all molecular motion ceases and the absence of heat results. This point is measured at -459.6 Fahrenheit and -273.2 Celsius.


A measure of a material's capacity to take up and assimilate liquids (from liquid or vapour form).


A measure of a material's total capacity to take up and assimilate liquids (liquid or vapour form).


Transformation of radiant energy to alternate through interaction with matter.

Acoustical Treatment

The application of absorbent insulation to control sound.

Acrylic Resin

Resin produced by the polymerization of acrylic monomers like ethyl acrylate and methyl methacrylate.


A bonding agent used to combine materials.

Aggregate Size

The size of particles in a cement, concrete, loose fill insulation, or similar materials. The size is presented as a percentage of those particles which will or will not pass-through the mesh of a given screen area.


The cracking of a coating or mastic into large segments. Incomplete cracking is usually referred to as checking.


The concept of surrounding or encompassing as it applies to temperature, humidity, and atmospheric conditions.

Ambient Temperature

The average temperature of air or any other medium surrounding an object.


Friendship or peaceful relations, as between neighbours or nations.

Anti-Abrasive Coating

A material which prevents erosion by placing a "cushion" between pipes, ducts, vessels, and adjoining insulation.


An application which prevents condensation.

Apparent Thermal Conductivity

The thermal conductivity of any material exhibiting thermal transmission through heat transfer. This results in variations in the thickness and surface emittance of the material. See also "Conductivity, Thermal."

Apparent Thermal Resistivity

The resistance of any material exhibiting thermal transmission via heat transfer. This results in variations in the thickness or surface emittance of the material. See also "Resistivity," "Thermal," and "R-Value."

Appearance Covering

Materials used to improve the aesthetics of finished insulation.

Application Temperature Limits

The minimum and maximum temperature range in which it is usually safe to service finishes, adhesives, and sealants without placing the integrity of the material at risk.

Area Weight

The weight per unit area of a given sample, expressed in units of lbs/ft² (kg/m²).

Asbestos Abatement

The removal, enclosure, or encapsulation of asbestos-containing materials from a given area.

Asphalt Cut-Back

A petroleum asphalt coating containing mineral solvents, also referred to as a vapour-retarder mastic.

Asphalt Emulsion

The colloidal dispersion of a petroleum asphalt coating with water, also referred to as a breather mastic.

ASTM International

ASTM International provides a global forum for the development and publication of international voluntary consensus standards for materials, products, systems, and services.


Strapping used to fasten insulation and/or jacketing into place.


Blanket insulation manufactured to the dimensions required by a specific application.


The process of curling the edge of metal jacketing to accommodate sealing.


A substance contained in insulating materials that stabilizes the fibres in the material. Binders are also referred to as "thermal setting resin."

Blanket Insulation

A relatively flat, flexible sheet insulation used for large areas.

Blanket Insulation (Metal Mesh)

Blanket insulation covered by flexible metal-mesh facing attached to one or both sides.

Block Insulation

Rigid insulation preformed into rectangular units.

Board Insulation

Semi-rigid insulation preformed into rectangular units.


The combination of materials using adhesives.

Bond Strength

The unit load applied in tension, compression, peel, impact, cleavage or shear that is required to break the adhesive assembly at, or near the site, of the joint between materials.

Bonding Time

The amount of time required for an adhesive to reach its optimum bonding strength.

Brattice Cloth

A coarse, plain weave heavy cotton or jute fabric/fibre used as an air curtain to control mine ventilation.

Breaking Load

Any concentrated load which breaks a measured sample of insulation under testing (ASTM C-203 or C-446).

Bridging Ability

The ability of an insulation to span a gap in the substrate to which it is applied. Alternately, the ability of a weather or vapour barrier to span a gap in the insulation.

Breather Coating

A barrier designed to protect insulation systems from water resulting from rain, snow, sleet and other weather conditions. A breather coating which has been emulsified will prevent water from entering into the system, while simultaneously allowing small quantities of vapour produced by heat and moisture from within the insulation system to escape. Water-based breather coatings are emulsified and consequently allow vapour to pass through the system. Solvent-based breather coatings are not emulsified and do not allow vapour to pass.

British Thermal Unit (BTU)

The amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit (or 56 degrees celsius). A Btu is approximated as the amount of energy needed to lift a one-pound weight to 778 feet.

Butt Joints

The end joints of pipe insulation.

Butt Strip

Strips of jacket material applied to pipe insulation butt joints.

C-Value (Thermal Conductance)

See "Conductance, Thermal."

Calcium Silicate

Insulation manufactured primarily from hydrous calcium silicate, which contains reinforcing fibres.


A plain-weave cotton fabric used for jacketing or covering.


The ability of a cellular, fibrous, or granular material to diffuse water into its structure.


The process of sealing to make water and/or airtight.

Cellular Glass

Insulation manufactured from processed glass to form a rigid foam characterized by a closed-cell structure.

Cellular Insulation

Insulation composed of small, separated cells of glass or polystyrene, polyurethane, polyisocyanurate or elastomeric plastic.

Cement, Finishing

A mixture of dry fibrous or powdery materials, that develop a plastic consistency when mixed with water, and form a relatively hard, smooth and protective surfaced when dried in place.

Cement, Insulating

A mixture of dry granular, fibrous, or powdery materials that develop a plastic consistency when mixed with water, and form a coherent covering which resists heat transmission when dried in place.

Ceramic Fibers

Pure silica heated and expanded to produce fibers from which high-temperature insulation can be made. Ceramic Fibers are also referred to as "Refractory Ceramic Fibers."


A soft white or grey appearance on the surface of a weathered finish.

Chemical Resistance

The capability of a material to withstand exposure to acids, alkalis, salts and related solutions.

Chicken Wire

Hexagonal wire netting (poultry mesh) used as a metal-mesh facing or as reinforcement.


Protective covering installed over insulation. Also, see "Jacketing."


Allowance of adequate space for installation of insulation materials.


A liquid or semi-liquid that dries or cures to form a protective finish, suitable for applying to thermal insulation or other surfaces in a dry thickness of 30 mils or less per coating.

Coefficient of Expansion/Contraction

The change in a unit length of a material that corresponds with a unit change it the material's temperature.


The provision of enough fuel to make insulation capable of burning.

Compaction Resistance

The property of a fibrous or loose-fill material that resists compaction under heavy loads or vibration.

Compatible Materials

Two or more substances that can be mixed or used together without separation, reaction, or adversely effects.

Compressive Strength

The property of an insulation material that resists any change in its dimensions when compacted.


When water vapour turns into liquid upon contact with cold surfaces.

Condensate barrier

Material used as an inner lining for metal jacketing weather barriers in an insulation installation. Condensate barriers bar alkaline condensate, which tends to form on the inner surface of the metal jacket upon contact.

Conductance, Air Film

The time rate of heat flow from a unit area of a surface to its surroundings. Air film conductance is induced by a unit temperature difference between the surface and its surrounding environment.


The transfer of heat energy within a body or between two bodies which come into physical contact.

Conductance, Thermal (C-Value)

The time rate of steady state heat flow through a unit of a material. Thermal conductance (or C-Value) is induced by a unit temperature difference between the surfaces of the material.

Conductivity, Thermal (K-Value)

The amount of heat which passes through a unit area of a homogeneous substance, through a unit thickness, in a unit of time, for each unit in temperature difference. The lower the k-value, the higher the insulating value.

I-P units are Btu – in / hr – ft2 - °F and typical SI units are Watts / m - °C.

Contact Adhesive

An adhesive that when tacky to the touch will adhere instantaneously on contact.


The transfer of heat by movement of fluids.


The deterioration of any material as a result of chemical action. Rust is an example of corrosion effects on steel.

Corrosion Retarder (as Related to Insulation Jacketing)

See "Moisture Barrier."


Screwed, soldered, welded, or mechanically grooved connections between links of pipe.


To place insulation and/or finishing materials on, over, or around a surface to insulate, protect or seal.


The area covered per unit volume of a coating to obtain a given dry thickness and desired level of performance.

Covering Capacity, Dry

The area covered by a dry thickness of 1 inch (25 mm) by 100 lb. (45.4 kg) of dry cement, when the cement is mixed with the recommended amount of water, then molded and dried to constant weight.

Covering Capacity, Wet

The area covered by a wet thickness of 1 inch (25 mm) by 100 lb. (45.4 kg) of dry cement, when the cement is mixed with the recommended amount of water and molded.


Corrugating of metal edges to reduce diameter or facilitate bending. Crimping is used to mate fitting gores with the beaded edges of adjacent segments. It is also used on end caps for tanks and vessels.

Cryogenic Insulation

Insulation for extremely low-temperature surfaces from –100 F to –459 F (absolute zero).

Cupped Head Pin

Capacitor discharge welded insulation fastener pin with a fixed washer.


To change the properties of a plastic or resin by chemical reaction, most often through application of heat or introduction of a catalyst.

Curing Time

The length of time necessary to cure plastic or resin by chemical reaction.

Cut Back Products

Petroleum or tar residuals which have been blended with distillate solvents.


The separating or breaking down of a substance into its component compounds or basic elements.


The separation of the individual layers of material contained within in a laminate.

Density, Apparent (of Applied Insulation)

The mass per unit volume of in-place mass thermal insulation.

Density, Real

The weight of a unit volume of a material in its manufactured state, excluding all voids, most often expressed in pounds per cubic foot.

Dew Point

Saturation temperature at which water vapour and liquid occur simultaneously.

Dewpoint Temperature

The temperature at which water vapour begins to condensate at a given humidity level and level of pressure.

Diatomaceous Silica

Insulation composed principally of diatomaceous earth, most often containing reinforcing fibres.

Diffusivity, Thermal

The ratio of thermal conductivity of a substance, to the product of its density and specific heat.

Dimensional Stability

Any property of a material that enables it to maintain its original size, shape, and dimensions.


To change the physical state of a substance through the loss of solvent constituents, via evaporation, absorption, oxidation, or a combination of these factors.

Dual Temperature

Equipment systems that operate as cold condition and hot application.


A passageway made of sheet metal or other suitable material used for moving air or gas.


A preformed flexible sheet of heat transfer compound used between plate type coils and process vessels.


A closed-cell foam insulation containing elastomers which exhibit high elasticity.


The process of dispersing insoluble fine solids or liquids in other liquids, usually water.

Epoxy Resins

A two-part epoxy compound and catalyst that cures at ambient temperatures to form finishes which are highly resistant to solvents and chemicals. Epoxy resins are high bond adhesives.

Expanded Metal Lath

See "Lath expanded metal".

Exposed Spaces

Those spaces not referred to as concealed or as defined by the specifier.


A thin covering adhered to the surface of insulation prior to field installation.


An insulation material made of one or more types of interlocking fibres which are compacted under pressure.


See "Fibrous Glass".

Fibrous Glass

A synthetic vitreous fibre insulation made by melting silica sand and other inorganic materials, and forming the melt into fibres. Other materials are often applied to the mineral wool, including binders, oils, etc. Common names include "fibre glass," or "fibreglass."

Fibrous Insulation

Insulation composed of small diameter fibres that finely divide air space, most often made from silica, rock wool, slag wool, or alumina silica.

Film (Wet)

An applied layer of mastic or coating before it is cured or dried.


Jackets, mastics, or films used for aesthetics, or to protect insulation from weather, and mechanical or personnel abuse.

Finishing Cement

A mixture of various insulating fibres, fillers, and binders with water, with or without hydraulic cement, to form a smooth "trowelable" paste insulation for smooth application over insulating cement or unfinished block insulation.

Fire Resistance

The ability of a material to protect against and withstand fire. Fire resistance is characterized by the ability to confine a fire and permit the continuation of a structural function's performance.

Fire Retardance (FR)

The property of a material which slows the spread of fire.

Fire Stops

A fire stop is a fire protection system used to seal openings and joints in fire-resistant wall and floor assemblies.

Fitting Cover

Pipe fitting insulation or preformed jacketing which is composed of a specified insulation thickness, and which may also be preformed.

Flash Point

The temperature at which combustion is initiated.


The arrangement of a metal or other weather barrier.


The property of a material which allows it to be bent (flexed) without losing strength or integrity.


A rating usually expressed in hours, F-Rating indicates the length of time a fire-resistant barrier can withstand fire before being consumed, or permitting the passage of the flame through an opening in the assembly.

F-Ratings are determined by ASTM E 814 (UL 1479).

Freeze/Thaw Stability

A property which ensures a material is still usable at room temperature even once it has been subjected to temperatures below freezing.

FSK (Foil Scrim Kraft)

A laminate composed of a thin layer of aluminum foil, glass fibre reinforcing scrim, and kraft paper.

Gallon Weight

Weight of the standard US volumetric unit of 231 cubic inches, often used as a quality control check.

Glass Cloth

Glass fibre with a closed weave, used as a finishing jacket.

Glass Fabric

Glass fibre with an open weave, used as a reinforcing membrane.

Glass Fiber

An inorganic fibre manufactured as a continuous filament from molten glass or silica, normally used for reinforcement, tissue, or textiles.

Glass Scrim

See "Glass Fabric."


The curved segment of a finishing jacket used for elbows, tank heads, or other curved surfaces.

Granular Insulation

Insulation composed of small nodules that contain voids or hollow spaces. Granular insulation may be calcium silicate, diatomaceous earth, expanded vermiculite, perlite, cellulose, or microporous insulation.

Heat Flow, Heat Flow Rate

The quantity of heat transferred to or from a system in a given unit of time.

Heat Transfer Cement

A soft, plastic material which solidifies to a rock-like hardness under use owing to a high coefficient of heat transfer. This type of cement is used to bond tubes and other heat-conveying devises to pipes and equipment.

Heat Transfer Compounds

Compounds designed to provide an efficient thermal connection between tracers and process equipment, wherever high temperature maintenance is required. Normally used with a channel system.

Heat Resistance

The ability to withstand heat without experiencing deterioration or failure.


To cover with a material of low thermal conductivity in order to reduce the transmission of heat.

Insulating Cement

A mixture of insulating fibres, binders, and water which is combined into a moldable paste insulation for application to fittings, irregular surfaces, or voids.


Materials or material combinations which retard heat flow.

Jacket, (Insulation)

A protective covering installed over thermal insulation.

K-Value (Thermal Conductivity)

See "Conductivity, Thermal."


A method of joining or securing insulation materials, reinforcements, or finishes for insulation materials using eyelets, hooks, wire, cord, and other ties and fasteners.

Lagging (Insulation)

A block material for insulating tanks and boilers, usually curved or tapered. Alternately, lagging is insulation used on pipe, tanks, ducts, vessels, and other mechanical equipment. Lagging insulation is usually applied in the form of cut, pieced together, or mitred parts.

Lagging (Jacketing)

Jacketing installed over insulation. Also see "Jacket."


A product made by bonding two or more layers of material.

Loose-Fill Insulation

Insulation in granular, nodular, fibrous, or powder format, installed by hand or by pouring or blowing.

Loose or Fill Insulation

Insulation made of loose granules, fibres, beads, and flakes, which must be contained. Often used in cavities.


A protective coating applied by spray or trowel to weatherproof or otherwise prevent deterioration of the insulation to which it is applied.


Semi-flexible insulation composed of various, randomly-arranged fibres, used to support other materials.

Mean Specific Heat

The quantity of heat required to change the temperature of a a unit of a given substance one degree. Mean specific heat is measured as the average quantity over a specified range of temperature.

Mean Temperature

Sum of a cold surface temperature and a hot surface temperature, divided by two. Thermal conductivity charts are calculated using mean temperatures.

Membrane Reinforcement

Woven or non-woven fabrics used for saturation, embedded in mastic and coating applications to provide strength, continuity, and impact resistance. See also "Glass fabric."

Metal Lagging

See "Jacket."

Mineral Fibre

Insulation composed predominantly of fibres manufactured from rock, slag, or glass, with or without binders.

Mineral Wool

A synthetic vitreous fiber insulation made by melting predominantly igneous rock, and or furnace slag, and other inorganic materials, and then physically forming the melt into fibers. To form an insulation product, there are often other materials applied to the mineral wool such as binders, oils, etc.

Moisture Barrier (as related to Insulation Jacketing)

A polymeric film or coating applied to the inner surface of metal jacketing for the primary purpose of reducing electrolytic, pitting, or crevice corrosion of the jacketing.

Discussion – moisture barriers are not water vapor barriers or water vapor retarders

Mold and Mildew Resistance

The ability of a material to discourage the formation of fungus.


National Insulation Association


North American Insulation Manufacturers Association


Materials which do not support fire via fuel or heat.


Materials which release little heat when exposed to fire or flame.

One-Coat Cement

A mixture of various insulation fibres, fillers, and binders with hydraulic-setting cement. One-coat cements may be applied directly to fittings to match the thickness of the adjacent insulation, and smoothed to a hard finish.

One Fibre per Cubic cm Air (1 f/cc)

On this site, 1 f/cc refers to the allowable exposure limit for fibreglass, rock wool, and slag wool insulations. 1 f/cc is the ACGIH TLV, the HSPP voluntary exposure limit recommended by the National Academy of Sciences, and the State of California's established PEL for fibreglass, rock and slag wool insulation fibres.


Accepted unit of water vapour permeance, expressed as one grain per square foot, hour, and inch of mercury.

Perm Inch

Accepted unit of water vapour permeability, expressed as one grain per square foot, per hour, per inch of mercury and inch of thickness.

Pipe Insulation

Insulation suited to cylindrical surface applications.


Polyisocyanurate, also referred to as PIR, polyiso, or ISO, is a thermoset plastic often produced as a foam, and used as rigid thermal insulation. The chemistry of PIR is similar to that of polyurethane (PUR).

R-Value (Resistance)

See "Resistance, Thermal."

Refractory Insulation

Insulation for extremely high temperatures, usually applied to projects above 1500°F.

Refractory Materials

Materials that resist significant deformation or chemical change at high temperatures. Refractory materials are manufactured in blanket, block, brick, or cement form.

Reinforcing Cloth or Fabric

A resilient woven cloth or glass fabric used to reinforce mastics.

Removable and Reusable Covers

Mesh fabric or sheet metal insulation or pads designed to be readily removed and reinstalled.


The ability of a material to recover its original shape and thickness after compression.

Resistance to Acids, Caustics, and Solvents

The ability of a material to resist decomposition by acids, caustics, and solvents.

Resistance to Air Erosion

The ability of a material to resist surface erosion caused by air currents.

Resistance, Abrasion

A material's ability to withstand scuffing, scratching, rubbing, or wind-scouring.

Resistance, Freeze-Thaw

Resistance to cycles of freezing and thawing that could otherwise impact a material's application, appearance, or performance.

Resistance, Impact (Toughness)

The ability of a material to withstand mechanical blows or shock without damage.

Resistance, Thermal (R-Value)

A measure of the ability to retard heat flow. R-value is the numerical reciprocal of "U" or "C," thus R = 1/U or 1/C.

Thermal resistance R-value is used in combination with numerals to designate thermal resistance values: R-11 equals 11 resistance units. The higher the "R," the higher the insulating value. I-Punits are °F – ft2 – hr / Btu; the SI units are °C – m2 / W.

Resistivity, Thermal r

The unit rate of heat flow through a unit area, induced by the temperature difference between two parallel surfaces of a homogeneous material of unit thickness. r in SI units: m/K/W r in inch-pound units: h ft F/Btu or, h ft ² F/Btu in

Rigid Channel

A galvanized or stainless steel channel designed to carry pre-formed or cement-form heat transfer compound for use on straight sections of piping.

Rigid Wrap-around Insulation

Segments of insulation material applied to a facing to provide rigid insulation materials with improved flexibility on application.


The material property which measures the degree of a material's opposition to bending or flexing under load.

Rock Wool (Mineral Wool)

A synthetic, vitreous fibre insulation made by melting predominantly igneous rock and other inorganic materials, and physically forming the resulting melt into fibres. See also "Mineral Wool."


To cut grooves in rigid insulation so that it may be cracked and fitted to round or irregular surfaces.


Insulation sealants are used primarily for water and vapour protection. They may also be used as adhesives, and for expansion joints on metal, masonry, cellular glass, etc. Sealants must exhibit low shrinkage, strong adhesion, and permanent flexibility.


A liquid coating used to prevent excessive absorption of finish coats by porous surfaces.

Surface Temperature Limits

The minimum and maximum temperatures a jacket or coating may be subjected to once applied over top of insulation. Service temperature limits do not refer to the operating temperature of the equipment, vessel, or pipe.

Shear Strength

The ability of a material to resist cleavage/splitting.

Shelf Life

The period of time during which a materials like adhesives, coatings, or sealants can be safely stored under a specified temperature, without sacrificing their physical properties or usefulness.


An indication of a material's proportionate loss in dimensions or volume due to temperature changes or aging.

Smoke Toxicity

The degree to which smoke is hazardous to health.

Snap Trace

A pre-formed compound designed for rapid, consistent installation of insulating materials in a channel system.

Soaking Heat Stability

The property of a material which enables it to withstand a soaking heat over an appreciable length of time without any change in its properties or dimensions.

Softening Point

The temperature at which material changes from rigid to soft or malleable.


A liquid or gas in which a solute, or other substance (solid, liquid, or gas), is dissolved to form a solution.

Standing Seam

Folded configuration of jacketing used to provide strength and rigidity, while also creating a watershed for top, flat surfaces of ductwork, vessels, and tanks.

Surface Temperature Limits

The surface temperature of finished insulation.


Thermal Insulation Association of Alberta


Thermal Insulation Association of Canada


The property of an adhesive that enables it to create a measurable bond once the adhesive and adherent are brought into contact under low pressure.

Tear Strength

The ability of a material to resist being pulled apart by opposing forces.

Temperature Limits

The highest and lowest temperatures at which a material will avoid any change to its physical properties.

Test Specimen

Unit of a testing material used to obtain a single test result.

Thermal Conductivity (K-Value)

See "Conductivity, Thermal (K-Value)

Thermal Capacity

The quantity of heat required to change the temperature of a material by one degree. For a homogeneous material, thermal capacity is the product of mass and heat. For a non-homogeneous body, it is the sum of the products of mass and specific heat of the individual constituents of the material. Also known as heat capacity.

Thermal Insulation

Insulation appropriate to the general temperature range of –300 F to 1800 F. Also defined as a material, or assembly of materials, used to resist heat flow.

Thermal Insulation System

Applied or installed thermal insulation, complete with complimentary accessories, vapour retarders, and facings.

Thermal Properties of Insulation

Insulation properties which determine how an insulating material will react when exposed to excessive heat or cold and changes in temperature over a period of time. Expressed as C-value, K-value, R-value, and U-value.


The inside radius of an elbow.


Use of a companion line containing hot fluid or electric resistance to supply auxiliary heat to pipework or equipment via thermal or mechanical bonding.

Transference, Thermal

The steady stream of heat flow to (or from) a material, through applied thermal insulation, via conduction, convection, or radiation. Thermal transferance is expressed as the time rate of heat flow per unit area of the material's surface, given the unit temperature difference between the material's surface and surroundings.

Transmission, Heat

The quantity of heat flow due to heat transfer initiated by prevailing conditions.

Transmittance, Thermal (U-Value)

The combined thermal value of all materials in a insulation system, air space, or surface air film.

Heat transmission in unit time is measured as the unit temperature difference exhibited on all sides of an insulation system. I-P units are Btu / (hr – sq ft – deg F temperature difference). SI units are W / (sq m – deg C temperature difference. This rate of heat transmission is also known as the overall coefficient of heat transfer.


An expression, in hours, of the length of time the temperature on the non-fire side of a fire-rated assembly exceeds 325°F above its ambient temperature, as determined by ASTM E-814 (UL-1479).


Insulation applied on piping and equipment located below grade and in direct contact with surrounding soil.


Plastic rigid polyurethane closed-cell foam insulation available in board, pipe, or formed-in-place formats.

U-Value (Transmittance)

See "Transmittance, Thermal (U-Value)"


Device which regulates liquid or gas flow by opening, closing, or obstructing its passageway.


Insulation composed of natural vermiculite ore expanded to form an exfoliated structure.

Vibration Resistance

Ability to resist mechanical vibration without wearing away, setting or dusting.


The name of a class of resins or sheeting.


World Insulation & Acoustic Congress

Washer (Insulation Clip)

Self-locking flat metal device applied to anchor pins in order to to secure insulation in place.

Water Absorption

Increase in a material's weight after immersion in water, expressed as a percentage of its dry weight or volume.

Water Resistant

Capable of withstanding limited exposure to water.

Water Vapour Retarder (Barrier)

A material or system that significantly impedes the transmission of water vapour under specified conditions.

Water Vapour Retarder Jacket

Any material or composite which serves as a water vapour retarder, and is applied as jacketing/covering to insulation material. Water vapour retarder jackets may be factory furnished or field applied, and may, or may not be adhered to the insulation material.


Impervious to prolonged exposure to water.

Weather/Vapour-Retarder (barrier)

A vapour retarder designed to protect against atmospheric conditions.

Weather Barrier

A breather jacket or coating which allows water vapour to pass, while protecting against atmospheric conditions.

Weld Pin

Insulation accessory made from carbon steel, stainless steel, or aluminum, available in various lengths, and used to attach insulation to metal surfaces. Weld pins are applied by welding, usually with a weld gun.