We've compiled and maintain a list of useful terms used in the glass fabrication industry. This comes from our vast experience in the glass production industry. If you have any further questions, or would like to know more about what we do, don’t hesitate to get in touch with us.
That property of a coating or sealant which measures its ability to stick or bond to the surface to which it is applied.
The amount of air leaking in and out of a building through cracks in walls, windows and doors.
To heat above the critical or re-crystallization temperature, then controlled cooling metal, glass or other materials to eliminate the effects of cold-working, relieve internal stresses or improve strength, ductility or other properties.
To provide an extremely hard non-corrosive oxide film on the surface of aluminum, by electrolytic action. The electrochemical process produces an anodic coating by conversion of aluminum into essentially aluminum oxide. Appearance depends upon both the alloy involved and the surface preparation. Anodic coatings may be transparent, of varying shades of silver, gray or brown, or colours may be incorporated by the use of dyes or pigments.
Similar to a casement except the sash is hinged at the top and always projects out.
A compressible material placed in a joint before applying a sealant, to limit the depth of the sealant configuration. The material may also act as a bond breaker.
The same as bedding or bed glazing. The small bead of glazing material between the glass and the sash and on the opposite side of the glass from the face glazing. Also, the act of applying the back putty before placing the glass into position.
An arrangement of three or more individual window units, attached in such a way as to project from the building at various angles. In a three-unit bay, the center section is normally fixed with the end panels operable as single hung or casements.
BED OR BEDDING
The bead of a compound applied between a lite of glass or a panel and the permanent stop or sight bar of the sash or frame, and usually the first bead of compound to be applied when setting glass or panes.
BEVELED OR CAP BEAD
Bead of compound applied so as to have a slanted top surface so water will drain away from the glass or panel.
Amount of overlap between the top of a stop and the inserted edge of a panel or lite of glass; also the amount of overlap of a heel bead into the glass or panel.
A piece of neoprene, silicone, or other suitable material used to position the glass in the frame. (See spacer.)
A sealant or compound after application in a joint, irrespective of the method of application, such as caulking bead, glazing bead, etc. Also, a molding or stop used to hold glass or panels in position.
To shim, level and plumb windows in the required position.
A release type of material (such as polyethylene film sheet with adhesive on one side) used to prevent adhesion of the sealant to the back-up material or back of the joint. Used in expansion joints or splice joints.
A bow window can be arranged with three or more equal width units. They can be fixed or operable or mixed in any combination. They are usually mulled together with a small angle such as 13 degrees.
British Thermal Unit. The energy used for heating and cooling is measured by the number of BTU’s needed to keep a building at a comfortable temperature. Scientifically, it is the amount of heat energy necessary to raise the temperature of one pound of water one degree Fahrenheit.
Application of compound or sealant to the flat surface of a member before placing it into position.
A synthetic rubber prepared by co-polymerization of isobutylene with a small amount of isoprene (both ingredients are gaseous hydrocarbons). It can be used as a sealant and architectural glazing tape.
A single unit of glass, generally longer vertically than horizontally, that can either be opened to the outside (most common) or inside.
A material which markedly speeds up the cure or reaction of another substance when added in minor quantities.
The blocking of exterior air or moisture leaks by filling cracks around doors, windows, or anywhere else where two surfaces meet and have minimum movement with a “putty” compound. Large cracks can be stuffed with mineral wood and weather sealed with caulking.
A type of building wall construction consisting of an outer wall fastened to an inner wall separated by an air space.
The sealing of the joints around lites of glass or panel set in a U-shaped channel employing removable or fixed stops.
A change in the properties of a material due to polymerization of vulcanization, which may be effected by heat, catalysts, exposure to the atmosphere, or combinations of these.
The space or distance allowed for anchorage or erection purposes or to accommodate dimensional variations in a building structure.
Failure of a compound when placed under a strain, in which – because of insufficient elasticity and elongation to absorb the strain – the compound splits and opens.
Process of heat transfer through a material from a warm surface to a cool surface.
Bead of compound with convex exposed surface.
Bead of compound with a concave exposed surface.
Pressure exerted on a compound in a joint, as by placing a lite of glass or panel against bedding, or placing a stop in position against a bead of compound.
When water vapor, which is present in all but the driest air, comes in contact with a surface that is below what is called the “dew point temperature,” the vapor becomes liquid and is called condensation. An example is as follows: condensation forms on a glass of ice water since the surface of the glass is down to the dew point temperature of the inside air.
Condensation Resistance Factor. Gives an indication of a window’s ability to resist condensation. The higher the CRF, the less likely condensation is to occur.
The time required to complete the chemical reaction of a product to reach its final physical form as a result of chemical reaction.
An exterior building wall which carries no roof or floor loads and consists entirely or principally of metal, or a combination of metal, glass and other surfacing materials supported by a metal framework. There are two basic types:
A unit for expressing the relative intensity of sounds on a scale from zero for average least perceptible sound to about 130 for the average pain level.
An extremely porous crystalline substance used to absorb moisture from within the sealed air space or an insulating glass unit.
The temperature at which the condensation of water vapor in a space begins, at a given state of humidity and pressure, as the temperature is reduced. Used in testing sealed insulating glass. The lower the number, the higher the resistance to forming condensation.
In general, any use of two thicknesses of glass, separated by an air space, within an opening, to improve insulation against heat transfer and/or sound transmission. In factory-made double glazing units the air between the glass sheets is thoroughly dried and the space is sealed airtight, eliminating possible condensation and providing superior insulating properties.
A window consisting of two sashes of glass operating in a rectangular frame, both the upper and lower halves can be slid up and down and usually use a counter balance mechanism to hold the sash in place.
A method of securing glass in a frame by use of a dry, preformed resilient gasket, without the use of a compound.
A sealant that exhibits properties of high structural strength and low moisture vapor transmission rates.
DYNAMIC ELONGATION TEST
Elongation or stretching of a material under continuous movement.
Pliability, ability to take up an expansion and contraction; opposite of brittleness.
An elastic, rubber-like substance which may either occur naturally or be produced synthetically.
A weathering compound with good resistance to ultra-violet radiation. Good memory and weathering characteristics.
A thermoplastic resin formed by combining epichlorohydrin and bisphenols. Requires a curing agent for room temperature or elevated temperature hardening. Has outstanding adhesion, strength and excellent chemical resistance.
Glass set from the exterior of the building.
The removable molding or bead that holds the lite or panel in place when it is on the exterior side of the lite or panel as contrasted to an interior stop located on the interior side of the lite or panel.
Buys glass from the glass manufacture and fabricates (tempering, laminating, insulating, etc.) to their customer's requirements.
On a rabbetted sash without stops, the triangular bead of compound is applied with a glazing knife after the bedding, setting and clipping the lite in place.
Exterior perimeter of the roof just below the roof-line, perpendicular to the overhang. Often covered with aluminum for a maintenance-free exterior.
Placing caulking or sealant in such a manner that it forms an angle between the materials being caulked.
A material such as cotton mop yarn, glass fiber insulation, oakum, polyethylene, Denver foam, etc., which is pressed into an opening or joint so that the compound applied to seal the joint will exert pressure and form good contact against the sides of the joint or opening.
1. A window which is stationary, also known as a picture window
2. The part of a sliding window or door which is non-moveable, also known as inactive.
Glass which has its bottom surfaces formed by floating on molten metal, the top surface being gravity formed, producing a high optical quality of glass with parallel surfaces and, without polishing and grinding, the fire-finished brilliance of the finest sheet glass. Float is replacing plate glass.
A method of glazing wherein the surfaces of the glass retaining members (stops or beads) are in the same plane normal to the glass as the side faces of the frame members; often achieved by providing pockets in these faces.
Compound applied in an opening or joint so that it is even with the top edge of the joint.
A deposit of contamination left on the inside surface of the sealed insulating glass unit due to extremes of temperatures. Usually happens with failed SIG.
A preformed shape of rubber or rubber-like composition used to fill and seal joints or openings either along or in conjunction with a supplemental application of a sealant.
Buys glass and installs it on a “contractor” basis. Examples: Installing the Window system in large office buildings, shopping center malls, etc.
The work of installing glass in a frame.
A molding or stop around the inside of a frame to hold the glass in place.
A soft dough-like material used for filling and sealing the space between a pane of glass and its surrounding frame.
Compound formulated to a degree of softness suitable for application through the nozzle of a caulking gun.
HAND OPERATED PRESSURE GUN
A caulking gun operated by hand an extruding the compound under pressure.
HEAD OR HEADER
Upper horizontal member of the master frame of a window, patio door, or entrance way.
The similar transfer of heat from outside to inside. Both heat loss and heat gain are measured in terms of the fuel consumption required to maintain a comfortable indoor temperature.
Glass which is reheated, after forming, just below melting point and then cooled. A compressed surface is formed which increases its strength. Used for spandrel glass.
The transfer of heat from inside to outside by means of conduction, convection, and radiation through all surfaces of the house.
HEATING DEGREE DAY
Heating and cooling engineers have found a way to relate the typical climate conditions of different areas to the amount of energy needed to heat and cool a building. The term they use is “Degree Days” using a base temperature of 65° F. A heating degree day is counted for each degree below 65° reached by the average (between the highest and lowest) daily outside temperatures in the winter. For example, if on a given winter day the high is 40° and the low is 20° , the daily average temperature is 30°. This is 35° below the base temperature of 65°. So, on that day, you would have gone through 35° heating degree days.
Compound applied at the base of channel, after setting lite or panel, and before the removable stop is installed, its purpose being to prevent leakage past the stop.
HERMETICALLY SEALED UNIT
An insulating glass unit made up of two lites of glass, separated by a roll formed aluminum spacer tube (at the full perimeter) which is filled with a moisture absorbing material. The unit is then completely sealed, creating a moisture-free, clean dead air space.
A window where the moveable panel slides horizontally.
The percentage of moisture in the air in relationship to the amount of moisture the air could hold at that given temperature. 100% relative humidity would be rain. The amount of degree of moisture in the air.
A synthetic, vulcanizable rubber manufactured by reacting polyethylene plastic with chlorine and sulphur dioxide.
Insulating glass refers to two pieces of glass spaced apart and hermetically sealed to form a single-glazed unit with an air space between. Heat transmission through this type of glass may be as low as half that without such an air space. It is also called Double Glazing.
Glass set from the interior of the building.
The removable molding or bead that holds the lite, as contrasted to an exterior stop which is located on the exterior side of a lite or panel.
The jalousie window is made up of horizontally mounted louvered glass that abut each other tightly when closed and extended outward when cranked open.
Two or more sheets with an inner layer of transparent plastic to which the glass adheres if broken. Used for overhead, safety glazing, and sound reduction.
Manufacturer of laminated glass, which consists of 2 or more layers of glass and/or plastic bonded together with a PVB or PVC interlayer.
A slatted opening for ventilation in which the slats are so placed to exclude rain, sunlight or vision.
Descriptive of compounds that remain elastic and pliable with age.
The original finish produced on aluminum by cold rolling or extruding.
Manufacturer of mirrors. Involves a process called “Silvering”, where glass is coated (sprayed) with silver, then copper, then a paint (protective) backing.
The 45-degree butted flush joints produced in some sash where vertical jamb members meet horizontal head and sill members.
A model of a section of a wall or its parts, built to scale or at full size, for purposes of studying its construction details, judging its appearance, and/or testing its performance.
MOISTURE VAPOR TRANSMISSION RATE
The rate at which moisture diffuses through a substance. Generally given in the following units: grams/meters2 x 24 hours. The lower the MVT rate, the greater the resistance of the sealant to moisture penetration.
A substance or simple chemical compound that can be polymerized, yielding a much larger molecule called a polymer.
An intermediate connecting member used to “marry” two or more windows or patio doors together in a single rough opening without sacrificing air or watertight performance. A mullion also can give added strength to the connection for structural stability.
A decorative design in cut-ups of glass lites, such as painted muntin grids (enamelite) applied to an interior lite of glass in a sealed insulating glass unit to simulate cut-ups of glass lites either in colonial or diamond patterns, or use of aluminum muntin bar between lites of glass in a sealed insulating glass unit to simulate cut-ups of glass lites either in colonial or diamond patterns, or use of aluminum muntin bar between lites of glass in a sealed insulating glass unit to simulate glass cut-ups, or use of actual vertical and horizontal bars to divide windows into smaller lites of glass. The bars are termed muntin bars.
Application of small bead of compound at the sight line by means of gun nozzle about 1/4″ x 1/8″ in opening size.
A synthetic rubber having physical properties closely resembling those of natural rubber but not requiring sulphur for vulcanization. It is made by polymerizing chloroprenes. The latter is produced from acetylene and hydrogen chloride.
A class of rubber-like co-polymers of acrylo nitrile with butadene. There are many types and a few of the trade names are Funa N, Butraprene, and Chemigum. It has high resistance to solvents, oils, greases, heat, and abrasion.
A high solids content, mastic material furnished in varying thicknesses and widths, in roll form; easily deformed and permanently soft and tacky.
Descriptive of a product that does not form a surface skin after application. Usually remains tacky or sticky.
Characteristic of a compound which will not stain a surface by bleeding or migration of its oils or vehicle content.
Any substance which does not evaporate or volatilize under normal conditions of temperature and pressure.
The tabular tip of a caulking gun through which the compound is extruded.
Hemp-like fibers in loose, ropey strands such as used by plumbers for packing pipe bell pints, and formerly used as joint filler before caulking where deep joints were present. Since superseded by materials such as ethafoam, polyethylene, etc., because of their greater freedom from ingredients that would stain masonry.
A coating such as paint, lacquer, enamel, or plastic film in which the principal ingredients are derived from animal or vegetable matter or from some compound or carbon (which includes all plastics).
Wooden exterior framing of the window.
1. A pre-assembled section of wall, including framing (if any), window area, and solid area.
2. A solid filler or facing material, either of one piece or an assembly, or use with a surrounding frame. 3. S length of formed metal sheet, or an assembly of such sheets, usually with insulation between, as used for wall enclosure on industrial type buildings.
The picture window is stationary and framed so that it is usually, but not always, longer horizontally than vertically to provide a panoramic view.
Polished plate glass is a rolled, ground and polished product with true flat parallel plane surfaces affording excellent vision. It has less surface polish than sheet glass and is available in thickness varying from 1/4″ to 1-1/4″. Now replaced by float glass.
A light colored liquid, straight chain aliphatic hydrocarbon polymer. Non-drying and widely used as a major component in sealing and caulking compounds. It is essentially non-reactive and inert.
A material which has been polymerized from smaller molecules into longer molecules or chains. This can be done by addition or condensation reaction.
Treated by heating or cooking so that molecules of different substances unite into larger molecules of a different substance with individual characteristics.
A synthetic rubber formed by the reaction of a glycol with an isocyanate. When used in sealants, yields a rubber-like material with excellent strength characteristics. Used as exterior sealant and sealed insulating glass sealant.
A special coating designed to enhance the adhesion of sealant systems to certain surfaces or a final organic coating to a surface.
A window which is installed during the initial construction and services as an integral part of the structure. Not to be confused with storm windows which serve as a secondary weathering device.
Sealing of a porous surface so that compound will not stain, lose elasticity, shrink excessively, etc., because of loss of oils or vehicle into the surface. Frequently the sign of inferior formulation when compound requires priming of surface before application.
Pounds per square foot (lbs/ft2). Abbreviation of pressure notation, used to describe wind velocity, barometric pressure.
A two-sided L-shaped recess in sash or frame to receive lites or panels.
Movement and distortion of sash or frame because of lack of rigidity, or can be caused by adjustment of ventilator sections. Puts excessive strain on the sealant and may result in joint failure.
Any slot cut into masonry or formed into poured concrete or precast stone. May also be an open mortar joint left between two courses of bricks or stones, or a slot cut or cast into other types of building materials.
Adding or replacing items to existing buildings. Typical retrofit products are replacement doors and windows, insulation, storm windows, caulking, weatherstripping, vents landscaping.
A measure of resistance to heat gain or loss (insulative ability). R-Values rather than thicknesses can be compared for different materials, since 6″ or fiberglass (R-19) might compare with 12″ of wood or 18′ of stone.
The portion of a window which includes the glass and the framing sections which are directly attached to the glass. Not to be confused with the master frame into which the sash sections are fitted.
A continuous screw point on an aluminum extrusion designed to accept a specific diameter sheet metal screw and which will provide a secure means of fastening without the use of any reinforcement.
SCREW-ON BEAD OR STOP
Stop, molding, or bead fastened by machine screws as compared with those that snap into position without additional fasteners.
Compound used to fill and seal a joint, as contrasted to a sealer which is a liquid used to seal a porous surface.
Use of small blocks made of neoprene (preferred) or lead to distribute weight of glass or panel to strong point of sash, aid in centering glass or panel, and prevent glass to metal contact.
A term used rather loosely to describe a period when a material has either dried sufficiently through solvent release, or cured sufficiently through chemical reaction, to reach either a specified condition or a condition resulting from either of the two processes.
The ratio of the solar heat gains through a specific glazing system to the total solar heat gain through a single layer of clear, double-strength glass.
Strain put on a compound between two surfaces when there is a slipping movement of the two surfaces parallel to and in opposite directions along the length of the joint, such as occurs when an aluminum channel expands to a greater length than a glass panel when both are subjected to the same pronounced rise in temperature. This kind of strain tends to rub or knead the compound in opposite directions along the joint, as contrasted to other forms of strains which may try to pull the compound apart, by reason of the strain being at a right angle to the joint.
The length of time that packaged materials such as adhesives and sealants can be stored under specific temperature conditions and still remain suitable for use.
A transparent, flat glass whose surface has a characteristic waviness replaced by float glass. There were three basic classifications of sheet glass: 1) single strength 3/32″ thick; 2) double strength: 1/8″ thick; 3) heavy sheet which has 3 thicknesses: 3/16″, 7/32″ and 1/4″.
Generally, a wedge-shaped spacer (such as cedar shingles, in residential work) used to firmly locate a window or door frame into a rough opening. Anchors are normally set through the shim so as to maintain the correct frame placement after installation.
Small blocks of composition, neoprene, etc., placed under bottom edge of lite or panel to prevent its settling down onto the bottom rabbet or channel after setting, thus distorting the sealant.
Imaginary line along the perimeter of lites or panels corresponding to the top edge of stationary or removable stops, and the line of which sealants contacting the lites or panels are sometimes finished off.
The use of single thickness of glass in a window or door (as opposed to sealed insulating glass which offers far superior insulating characteristics).
Similar in appearance to the double-hung window, the single-hung window features a stationary top and a movable bottom half.
A slider window may have one or two movable panes of glass. Whatever the type, the windows slide horizontally in the frame.
Small blocks of composition, wood, rubber, etc., placed on each side of lites or panels to center them in the channel and maintain uniform width of sealant beads. Use of spacers prevents distorting the sealant excessively.
Devices that are U-shaped in cross-sections and an inch or more in length, placed on the edges of lites or panels to serve both as shims to keep the lites or panels centered in the sash or frames, and as spacers to keep the lites or panels centered in the channels and maintain uniform width of sealant beads. Usually made of rubber.
Heat-strengthened float glass with a colored-ceramic coating adhered to the back by a heat-fusing process. It has double the strength of annealed glass of the same size and thickness, enabling it to withstand greater uniform loads and thermal stresses. Spandrel glass cannot be re-cut after heat-strengthening. It is used as a fixed opaque colored glass on buildings in front of floor slabs and columns. It is available in a wide array of colors.
The upright vertical edges of a door, window or screen.
Either the stationary lip at the back of a rabbet, or the removable molding at the front of the rabbet, either or both serving to hold lite or panel in the sash or frame with the help of spacers. Also the part of a door frame against which the door closes.
A second set of windows installed on the outside or inside of the prime windows to provide additional insulation.
As with heat-strengthened glass, it is re-heated to just below the melting point, but suddenly cooled. When shattered it breaks into small pieces. It is approximately five times stronger than standard annealed glass. It must be used as safety glazing in patio doors, entrance doors, side lites, and other hazardous locations. It can’t be re-cut after tempering.
Manufacturer of tempered glass, which is heat treated either vertically or horizontally. Tempered glass, when shattered, breaks into rounded, smooth pieces of glass, rather than sharp, irregular pieces.
An element of low conductivity placed between elements of higher conductivity in an effort to reduce the flow of heat and cold, i.e., insulation.
A mineral admixture is incorporated in the glass, resulting in a degree of tinting. Any tinting reduces both visual and radiant transmittance.
A single or double hung window whose operable sash can be tilted into the room for interior washability.
Compound applied at the base of channel before setting lite or panel, its purpose being a secondary seal to prevent leakage past the exterior stop.
Permissible deviation from a nominal or specified dimension or value.
Operation of pressing in and striking a compound in a joint in order to press compound against the sides of a joint and secure good adhesion. Also, the finishing off of the surface of a compound in a joint so that it is flush with the surface.
Glass covered concrete wall that collects and stores heat passively. Heat radiates back into the outdoors or into internal air or heating.
A product which is necessarily packaged in two separate containers. It is comprised of a base and the curing agent or accelerator. The two components are uniformly mixed just prior to its use since, when mixed, it cures and its useful life is quite limited from the standpoint of application characteristics.
The invisible rays of the spectrum which are outside of the visible spectrum at its violet end. U.V. rays are found in everyday sunlight and can cause fading or chalking of dark paint finishes. Extreme U.V. exposure can cause certain plastic materials to distort.
Polyvinyl chloride material that can be both rigid or flexible, used in glazing channels and weathering of both windows and doors.
Holding glass in place with extruded vinyl channels or roll-in type.
Interior flexible continuous pressure fit gasket that insures a high compression seal between the glass and aluminum while applying pressure and seal to the outside architectural glazing tape.
A small opening in a wall or window member through which water may drain to the building exterior.
A method of sealed glass in a frame by use of a knife or gun-applied glazing compound or sealant.
A metal curtain wall of the commercial type, in which windows are the most prominent element. Also refers to smallest fixed lites used with wall systems.
Polished or clear glass, 1/4″ thick. Wire mesh is embedded within the glass such that the glass will not shatter when broken. The wire pattern is available in many types. It is frequently used in skylights, overhead glazing, and locations where a fire-retardant glass is required.