Annealed Glass : Another term for “ordinary” glass, most commonly used for float glass.

Aspect Ratio : The ratio of a longer side of panel to its shorter side.

Back Putty : The portion of the putty remaining between the glass and the depth of the rebate after the glass has been pushed into position.

Balustrade : A low wall forming a parapet to a stair, ramp, balcony, raised level, or a change in level.

Beads or Glazing Beads : A strip of wood, metal or other suitable material attached to the rebate to retain the glass.

Bedding Putty : The compound placed in the rebate of the opening into which the glass is bedded.

Bent Glass : Flat glass that has been shaped while into hot cylindrical or other curved shapes.

Bevelling : The process of edge finishing flat glass to a bevel angle.

Bite : The width of silicone used to bond the fin or frame member to the edge of the glass panel.

Block (Setting Block) : A small piece of wood, lead or other suitable material used between the edges of the glass (generally the bottom edge only) to centralize the glass in the frame (frequently called a setting block).

Bolted Structural Glazing (BSG) : Assembly of glass connected with stainless steel bolts where glass is also acting as a structural member.

Brewster Fringes: A phenomenon of light sometimes observed in a DGU.

Bullet Resistant Glass : A security glass capable of resisting attack from firearms and meant to stop bullets from piercing through it.

Ceramic Printed Glass : Also called ceramic fritted glass made by applying ceramic or glass frit before thermal tempering or bending of glass.

Chair Rail : A fixed glazing bar, or rigid push bar, that provides protection from human impact.

Chemically Tempered Glass : Tempered by means of chemical reaction instead of conventional method of thermal processing.

Clear Glass : Transparent glass.

Combustible material : The material which when burnt adds heat to a fire when tested for combustibility in accordance with the IS 3808-1979: Method of Test for Combustibility of Building Materials, National Building Code of India 2005.

Corridor : It means a common passage or circulation space including a common hall.

Critical locations : Parts of a building most likely to be subjected to accidental human impact.

Curtain Wall : Non load bearing structure / partition of glass attached in a frame.

Distance Piece : A small piece of wood, lead or other suitable material used to locate the glass between the bead and the back of the rebate, and prevent lateral movement.

Door : A hinged, sliding or otherwise supported openable barrier providing entrance to and exit from a building, corridor or room. Doors may be framed or unframed.

Double Glazing : Glazing that incorporates two panels, separated with an air space, for the purpose of sound insulation or thermal insulation or both.

Edge Polished : Usually applied to flat glass, the edges of which have been polished after cutting.

Edging : Grinding the edge of flat glass, to a desired shape, contour or size.

Enameling : A process of painting and baking on glass.

Exposed Edge : A glass edge that is not covered and is visible after glazing.

Extra Clear Glass : A purer form of float glass with lower iron content and improved transparencywithout greenish appearance of normal float glass.

Facade : Front or face of the building.

Faceted Glazing : Flat panes of glass installed vertically at an angle to each other, to form a faceted curve.

Fin : A piece of glass positioned and fastened to provide lateral support.

Fire resistant : It means the time during which a fire resistant material i.e. material having a certaidegree of fire resistance, fulfills its function of contributing to the fire safety of a building when subjecteto prescribed conditions of heat and load or restraint. The fire resistance test of structures shall be done in accordance with IS 3809-1966 Fire Resistance Test of Structure.

Fire Resistant Glass : A glass which will stay in place and prevent passage of flames, hot gases and smoke for an Integrity (E) of 30, 60, 90 or 120 minutes to facilitate safe evacuation of occupants in case of fire. It may have additional properties of Radiation Control (EW) or Insulation (EI).

Flat Glass : A general term covering sheet glass, float glass and various forms of rolled and plate glass.

Float Glass : A form of flat glass produced by reheating the continuous ribbon of glass whilst it floats over a bath of molten metal.

Frame : A structure manufactured from timber, metal, glass or other durable material or combinations of materials such as glass fins and structural sealant, supporting the full length of a glazed panel edge.

Frameless Glazing : A glazing surface, of one or more glasses, without any visible frame and held together by patch fittings, bolts or spiders.

Front Putty : The compound forming a triangular fillet between the surface of the glass and the front edge of the rebate.

Fully Framed Glazing : Panels that have all edges framed.

Glass : An inorganic, non-metallic material produced by the complete fusion of raw materials at high  temperatures, into a homogeneous liquid, which is then cooled to a rigid, condition essentially without crystallization.

Glazing : The securing of glass in prepared openings in windows, door panels, partitions and the like.

Green Building : A building designed for optimum energy and water usage and with concern for environment.

Grooving : A decoration process of making and polishing grooves on a glass surface.

Guarding : To prevent people from falling wherever there is a change in floor level by means of a permanent barrier.

Heat Soaking : Heat Soaking is done on toughened glass by reheating to a temperature of 290°C and keeping it at this temperature for eight hours and cooling it gradually.

Heat Strengthened Glass : Glass which has been heated past its softening point and chilled rapidly to increase its strength and make it thermally safe, but which breaks like annealed glass.

Heat Strengthened Laminated Safety Glass : Laminated Safety Glass utilizing two or more panels of heat strengthened glass in the make up.

High Activity Area : Where multiple human activity takes place.

High Risk Area : Area prone to human injury.

Infill Balustrades : Balustrades in which the supported glass resists an infill pressure and / or point load applied to the glass panel.

Insulating Glass Unit (IGU) : The standard configuration for residential and commercial windows consisting of a sealed unit of two panes of glass separated by a metal spacer.

Internal Partition : An interior dividing wall or such portion of an interior dividing wall that is not a door, side panel, shop front or atrium wall.

Iridescence : A phenomenon of light where strain patterns in tempered glass become visible in polarized light.

Laminated Glass : A composite material consisting of two or more sheets of glass permanently bonded together by a plastic interlayer material.

Laminated Safety Glass : Laminated glass that satisfies the requirements for a safety glazing material according to this guide.

Manifestation : Any technique for enhancing a person’s awareness of the presence of transparent glazed areas.

Maximum Thickness : The thickness of a panel of glass at the maximum thickness tolerance.

Minimum Thickness : The thickness of a panel of glass at the minimum thickness tolerance.

Mirror : A piece of glass silvered on one side, with a protective paint coating.

Monolithic Glass : A numeric designation used for reference purposes that indicates the approximate thickness of glass.

Newton Rings : Optical effect when two glass of a DGU are nearly touching at the center.

Nominal Thickness : A numeric designation used for reference purposes that indicates the approximate thickness of glass.

Non-combustible : It means, not liable to burn to add heat to a fire when tested for combustibility in accordance with the IS:3808-1966, Method of Test for Combustibility of Building Materials.

Patch Fittings : Hardware used for frameless tempered glass door assemblies, visible only as patches.

Pane : Single piece of glass cut to size for glazing.

Panel : An assembly containing one or more panes.

Parapet : It means a low wall or railing built along the edge of the roof or a floor.

Partly framed glazing : Panels that have one or more edges unframed.

Patterned Glass : Rolled glass having a distinct pattern on one or both surfaces.

Rebate : The part of a surround; the cross section of which forms an angle into which the edge of the glass is received.

Reflective Coated Glass : Glass with metallic or metallic oxide coating applied onto or into the glass surface to provide reduction of solar radiant energy, conductive heat energy and visible light transmission.

Residual protection : It is the protection provided to avoid the impact of human being to glass. It is provided on the side of glass where there are chances of Human impact. It can be achieved by providing a sill structure or a grill inside.

Safety organic-coated : A glazing material consisting of a piece of glass coated and permanently bonded on one or both sides with a continuous polymeric coating, sheet or film, which meets the test requirements of the safety glazing standards.

Security Glass : A laminated glass designed to resist or prevent forced entry. Generally used for large glasses in windows without safety grills.

Setting Blocks : Pieces of wood, hard rubber or plastic, on which the bottom edge of glass rests in a window sash.

Shower doors, shower screens and bath enclosure : The panels, doors or windows a enclosing or partially enclosing a shower or bath.

Side Panel : A panel (openable or inopenable) located adjacent to a doorway. It may or may not be in the same plane as the doorway.

Silicon: A type of Sealant, most commonly used with glazing of glass.

Sky Light : A fenestration surface having a slope of less than 60° from the horizontal plane. Other fenestration, even if mounted on roof of a building is considered as vertical fenestration.

Sloped overhead glazing : Glazing that is inclined at less than 75 degrees to the horizontal and located, wholly or partially, directly above an area that may be used by people.

Span : The dimension between supports. For panels supported on all four edges, it corresponds to the smaller of the sight size dimensions.

Spandrel : That portion of the exterior wall of a multistory commercial building that covers the area below the sill of the vision glass installation.

Spontaneous Breakage : Tempered glass breakage without any provocation or external reasons.

Stained Glass : An ancient form of decorative glass made by soldering glasses of different colors into a piece of art.

Tempered or Toughened : When float glass panels are heated and then cooled rapidly in a controlled Glass environment.

Tinted Glass : Normal float glass to which colorants are added during manufacturing process to achieve tinting and solar radiation absorption properties.

Thermal Breakage : Cracking of an annealed glass due to temperature difference at the center and edges of glass.

Transom : Horizontal bar of wood, aluminium or stone etc. across a window, door or partition.

Tripple Glazed Units : An insulated glass unit using three plates of glass separated by two air gaps.

Toughened laminated Safety glass : Laminated safety glass utilizing two panels of toughened safety glass in the make up.

Unframed glazing : Panels without framed edges.

Wardrobe doors : Doors that provide access to built in storage areas, excluding those fitted to pieces of furniture that are not built into the building.

Weep Holes: Holes for drainage of water at the bottom of a window sash.

Wind Load : Load on glass because of the speed and direction of wind.

Window : It means an opening other than a door, to the outside of a building which provides all or part of the required natural light, ventilation.

Window Sill : Solid wall (brick or concrete wall) starting from the finished floor level to the base of first window or structural member consisting of a continuous horizontal metal/wooden forming the lowest member of a framework or supporting structure.

Wired Glass : Normal float or rolled glass with steel wire mesh embedded into it.

Energy and Light Definitions:

Light Transmission (LT) : Ratio of light flux transmitted through the glass to the incident light flux expressed by the illuminant CIE D65 with spectral density between 380 and 780 nm.

Direct Energy Transmission (DET) : Percentage of solar energy flux transmitted directly through theglass with a spectral density between 300 and 2150 nm (accordingly to CIE).

Energy Reflection (ER) : Percentage of solar energy flux reflected by the glass.

Energy Absorption (EA) : Percentage of solar energy flux absorbed by the pane or panes making up the glazed wall. The absorbed energy is then reradiated to the outside or inside at different rates depending
on the characteristics of the pane or panes of glass, wind speed, internal air speed, internal and external temperatures.

Solar Factor (SF) or Total Energy Transmission : A glass wall’s solar factor is the ratio of the total solar energy flux entering the premises through the glass to the incident solar energy flux. The total energy is
the sum of the incoming solar energy by direct transmission (DET) and the energy reradiated by the glass to the inside atmosphere after being absorbed by the glass (EA).

Solar Control Glass : A glass used for reducing the effect of heat transfer from solar radiation into the building.

Light Reflection (LR) : Ratio of the light flux reflected by the glass to the incident light flux expressed by the illuminant CIE D65.

Shading Coefficient (SC) : A measure of the heat gain through glass from solar radiation. Specifically the shading coefficient is the ratio between solar heat gain for a particular type of glass and that of double strength clear glass. The lower the shading coefficient, the lower the solar heat gain.

Solar Heat Gain Coefficient (SHGC) : A newly introduced term showing the amount of solar energy gained through a window. Multiplying the SHGC by 100 gives the percentage of solar energy allowed into
the building. Air Mass = 1.5.

U-Value (U-Factor) : A measure of the heat gain or loss through glass due to the difference between indoor and outdoor temperatures. It is also referred to as the overall coefficient of heat transfer. The lower
the U-Value, the better the insulating properties. The units are Btu/(hr)(sq.ft)(F).

K-Value : The European equivalent of the American (ASHRAE) U-Value. The units are W/sq.mt k and are based on a wind speed of 4.4 m/sec at 0°C with indoor temperature of 20°C. Relative Heat Gain (RHG) : The total heat gain through glass for a specific set of conditions. This value considers indoor/outdoor air temperature difference and the effect of solar radiation. The units are Btu/hr/sq.ft.

American Value : 1W/sq.mt k = 0.176 Btu/sq.ft./F/h