Glossary

Facade, ACP & glazing glossary

The terms engineers, architects and suppliers use, explained in plain English.

Technically reviewed by Er. Sanjay M. & Er. Aravind M.Civil Engineers, CIT Coimbatore · 10+ years in facades · Reviewed 7 Oct 2026

A

A2 Core

A2 core is an aluminium composite panel core with a very high mineral content that achieves Class A2 (limited combustibility) under the European fire classification EN 13501-1. It adds far less fuel to a fire than PE or typical FR cores, so it is often specified for tall or high-risk buildings. The rating belongs to the tested product, so always ask for the manufacturer's test report.

Aluminium Composite Panel (ACP)

An aluminium composite panel (ACP), also called aluminium composite material (ACM), is a flat sheet made of two thin aluminium skins bonded to a core of polyethylene (PE) or fire-retardant mineral-filled material. The face skin is factory-painted, usually with PVDF or polyester coating. ACP is light, rigid and easy to route and fold, which makes it the most common modern cladding material for facades, fascias and signage.

Aluminium Partition Section

An aluminium partition section is the extruded aluminium profile that forms the frame of an office or cabin partition. Sections are commonly described by their nominal width, such as the 2.5-inch and 4-inch series; larger, heavier series are chosen for taller partitions, longer spans and heavier glass. Sections are finished by anodising or powder coating and hold glass, board or ACP infill.

Related service: Aluminium Partition. See also: Anodising, Powder Coating, Toughened (Tempered) Glass

Annealed Glass

Annealed glass is ordinary float glass that has been cooled slowly during manufacture to remove internal stresses. It can be cut, drilled and edged easily, but it is relatively weak and breaks into large, sharp shards, so it is not a safety glass. Annealed glass is the starting material for toughened, heat-strengthened and laminated glass.

Anodising

Anodising is an electrochemical process that thickens the natural oxide layer on aluminium, creating a hard, corrosion-resistant finish that is part of the metal itself rather than a coat on top. It cannot peel or flake like paint. Common anodised colours for windows, partitions and curtain walls are silver (natural), bronze shades and black. Scratches are difficult to touch up invisibly on site.

Articulated Bolt (Routel)

An articulated bolt, often called a routel, is the stainless steel bolt that passes through a countersunk hole in a spider-glazed glass pane and connects it to the spider arm. Its ball-joint head lets the glass rotate slightly as it flexes under wind, so stress does not build up around the hole. Bushes and washers keep steel from touching the glass directly.

Related service: Spider Glazing. See also: Spider Fitting, Point-Fixed Glazing, Toughened (Tempered) Glass

B

Backer Rod

A backer rod is a flexible foam rod, usually closed-cell polyethylene, pushed into a facade joint before the sealant is applied. It controls the depth of the sealant, gives a firm surface to tool the sealant against, and stops the sealant bonding to the back of the joint. Bonding on only two sides lets the sealant stretch and compress freely as panels move.

Related service: ACP Cladding. See also: Weather Sealant, Thermal Movement Joint, Open Joint

Balustrade

A balustrade is the complete protective barrier along the edge of a staircase, balcony, terrace or mezzanine, including its infill panels, posts or base fixing and handrail. A glass balustrade uses toughened or laminated toughened glass as the infill, held by spigots, clamps, standoffs or a base channel. Its height and strength should follow the applicable building rules and the architect's design.

Related service: Glass Railings. See also: Laminated Glass, Toughened (Tempered) Glass, SGP Interlayer

C

Cassette System

A cassette system is a way of fixing ACP in which each panel is routed and folded into a shallow tray with returns on all sides, then hung on pins or hooks on the sub-frame. The fixings are hidden behind the panel, giving a clean face with even joints. Many cassette systems allow individual panels to be removed later without disturbing neighbouring panels.

Related service: ACP Cladding. See also: Routing and Folding, Sub-frame, Aluminium Composite Panel (ACP)

Ceramic Frit

Ceramic frit is a ceramic enamel paint that is screen-printed or rolled onto glass and then fused permanently into the surface during toughening or heat strengthening. It is used for dot and line patterns that cut glare and solar heat, decorative graphics, and fully opaque spandrel glass that hides slab edges. Because it is fused, the frit does not peel like an applied film.

Chalking

Chalking is the powdery white residue that appears on a painted or coated surface when sunlight slowly breaks down the coating's binder. On ACP it shows as faded colour and a chalky film that rubs off on a finger. Polyester coatings chalk sooner on sun-facing walls than PVDF coatings, which is why PVDF is preferred for exterior cladding in strong sun.

Coping

A coping is the cap that covers the top of a parapet or wall to keep rainwater out of the wall and the cladding behind it. On ACP facades it is usually a folded aluminium or ACP section that slopes slightly to drain inwards and has drip edges on both sides. Poorly sealed copings are one of the most common sources of facade leaks.

Curtain Wall

A curtain wall is a non-load-bearing outer wall, usually of aluminium framing and glass, that hangs on the front of a building and carries only its own weight and the wind load on it back to the floor slabs or frame. It does not hold up any floors. Curtain walls are built either as stick systems on site or as factory-made unitised panels.

D

Deflection

Deflection is how far a structural member bends under load. In facades, mullions, transoms, brackets and glass panes are checked for deflection under the design wind load, because excessive bending can crack glass, tear sealant joints, cause leaks and make panels look wavy. Allowable deflection limits come from the relevant design standards and the facade engineer's calculations.

Delamination

Delamination is the separation of layers that should stay bonded together. In ACP it means the aluminium skin peeling away from the core, often first visible at panel edges, and usually caused by poor bonding or moisture. In laminated glass it means the interlayer separating from the glass, which can start at exposed edges left in standing water. Delaminated ACP panels should be replaced.

Double Glazed Unit (DGU / IGU)

A double glazed unit (DGU), also called an insulating glass unit (IGU), is two glass panes separated by a spacer bar around the edge and sealed together, with a cavity of dry air or an inert gas such as argon. The cavity reduces heat transfer and traffic noise. Either pane can be toughened, laminated or coated, for example with low-E or solar-control coatings.

Related service: Curtain Wall Glazing. See also: Low-E Glass, Solar Control Glass, Curtain Wall

Drip Edge

A drip edge is a projecting lip or groove on the underside of a ledge, coping, canopy or soffit that makes rainwater drop off cleanly instead of running back along the underside or down the face of the wall. On ACP facades a folded drip at the top of bands and fascias prevents the black dirt streaks that rainwater otherwise leaves below joints.

Related service: ACP Signage & Fascia. See also: Flashing, Coping, Soffit

E

Extra-Clear (Low-Iron) Glass

Extra-clear glass, also called low-iron glass, is float glass made with a reduced iron content, which removes most of the green tint seen at the edge of ordinary clear glass. It transmits more light and shows true colours, so it is used for showroom display fronts, back-painted glass, glass railings with exposed edges and premium partitions. It costs more than standard clear glass.

F

Fascia

A fascia is a horizontal band across the front of a building, typically above a shop front or along a roof or slab edge, that hides the beam and gives a clean surface for signage. In modern shop fronts it is usually built from ACP on a sub-frame, with internal framing at sign locations and a drip edge on top to keep the face clean.

Related service: ACP Signage & Fascia. See also: Aluminium Composite Panel (ACP), Drip Edge, Sub-frame

Flashing

Flashing is a thin, weatherproof strip of aluminium, galvanised steel or membrane fitted at junctions in a building envelope, such as parapet tops, window heads, sills and the meeting point between cladding and glazing, to direct water away and back to the outside. Flashings work with sealants: the sealant closes the gap, and the flashing handles any water that gets past it.

See also: Drip Edge, Coping, Weather Sealant

Float Glass

Float glass is flat glass made by floating molten glass on a bath of molten tin, which produces sheets with flat, parallel surfaces and uniform thickness. Almost all modern window and facade glass starts as float glass. As made, it is annealed glass; it is then cut and processed into toughened, heat-strengthened, laminated, coated or double-glazed products.

Floor Spring

A floor spring is a hydraulic door closer concealed in a recess in the floor beneath a frameless glass door. The door pivots on it, and it controls the closing speed; many models can also hold the door open at a set angle. Floor springs must be rated for the weight and width of the glass door, and the floor recess is cut before final flooring.

Related service: Toughened Glass. See also: Patch Fitting, Toughened (Tempered) Glass

FR Core (Fire-Retardant Core)

An FR core is an ACP core loaded with a high proportion of mineral filler, such as aluminium or magnesium hydroxide, bound with a smaller amount of polymer. It resists ignition and slows the spread of flame far better than a plain polyethylene core. FR products differ in fire performance, so ask for the manufacturer's test documents and confirm the requirement with your architect or fire consultant.

Frosted (Acid-Etched) Glass

Frosted glass is glass with a translucent, satin-like surface that lets light through while blurring the view. Acid-etched glass gets this finish permanently by treating one surface with acid; sandblasting gives a similar look, and frosted films imitate it. Frosted glass is used for bathroom partitions, office privacy bands and doors where daylight is wanted but a clear view is not.

Related service: Office Glass Partitions. See also: Toughened (Tempered) Glass, Ceramic Frit

G

Gasket

A glazing gasket is a preformed rubber strip, usually EPDM or silicone, fitted in aluminium frames to seat the glass, cushion it from the metal and seal against air and water. In capped curtain walls and windows, gaskets are compressed by the pressure plate or glazing bead. Gaskets age with sun exposure and should be inspected along with sealant joints.

Glass Fin

A glass fin is a vertical strip of glass, usually laminated, set at right angles behind a glass wall to stiffen it against wind instead of using metal mullions. Fins keep the structure almost invisible, which is why they are used in frameless and spider-glazed showroom fronts and lobbies. Their size and build-up must be engineered for the height and wind load.

H

Heat Soak Test

A heat soak test is a process in which toughened glass panes are held at a high temperature in a special oven for several hours after toughening. Panes containing nickel sulphide inclusions are likely to break in the oven rather than on the building. Heat soaking reduces, but does not completely eliminate, the risk of spontaneous breakage, and it adds cost and time.

Related service: Toughened Glass. See also: Nickel Sulphide Inclusion, Toughened (Tempered) Glass

Heat-Strengthened Glass

Heat-strengthened glass is heated like toughened glass but cooled more slowly, making it about twice as strong as annealed glass. When it breaks, it cracks into larger pieces that tend to stay in the frame, so it is not a safety glass on its own and is often laminated. It is used for spandrel glass and facade panes exposed to heat stress.

HPL Cladding

HPL cladding uses high-pressure laminate panels made by pressing layers of resin-impregnated kraft paper under heat and high pressure, with a decorative, weather-resistant surface layer. Exterior-grade HPL panels are fixed on a sub-frame, much like ACP, and are popular for wood-look facades. Fire performance varies by product, so fire-rated grades and test documents should be checked.

I

IS 2553

IS 2553 is the Indian Standard specification for safety glass. Part 1 covers safety glass for general purposes, including use in buildings, and sets out the tests that toughened and laminated safety glass must pass. When you buy safety glass for doors, railings, shower partitions or facades, ask the supplier or processor for documents showing that the glass conforms to the standard.

Related service: Toughened Glass. See also: Toughened (Tempered) Glass, Laminated Glass, Heat Soak Test

L

Laminated Glass

Laminated glass is two or more glass panes bonded together under heat and pressure with a plastic interlayer, usually PVB or SGP. When it breaks, the fragments stay stuck to the interlayer and the pane remains in place as a barrier. It also cuts most UV and reduces noise. Toughened laminated glass is preferred for railings, canopies, skylights and overhead glazing.

Related service: Glass Railings. See also: PVB Interlayer, SGP Interlayer, Toughened (Tempered) Glass, Balustrade

Louvres

Louvres (or louvers) are a series of angled horizontal or vertical blades, usually aluminium, that let air and some light pass while blocking direct sun, rain and views. On facades they shade windows, screen air-conditioning units and service areas, and ventilate plant rooms. Louvres can be fixed or adjustable, and blade spacing and angle decide how much they shade.

Low-E Glass

Low-E (low-emissivity) glass has a microscopically thin metal or metal-oxide coating that reflects long-wave heat radiation while letting most visible light through. Solar-control low-E coatings also reduce the solar heat entering a building. Hard-coat (pyrolytic) low-E can be used as a single pane, while most soft-coat (sputtered) low-E must be protected inside a double glazed unit.

M

Mock-up

A mock-up is a full-size sample of part of a facade, built before production to confirm appearance, colour, joints and detailing, and sometimes to test water and air tightness. Once approved, it becomes the reference standard for workmanship on the rest of the job. Mock-ups are most useful on large or complex facades where a mistake would repeat across many panels.

Mullion

A mullion is a vertical framing member in a curtain wall, window or glazed partition. In a curtain wall, mullions run floor to floor, are anchored to the slabs with brackets, and carry the wind load from the glass back to the building. Their depth and section are sized for the wind load and span. The horizontal members between mullions are called transoms.

Related service: Curtain Wall Glazing. See also: Transom, Curtain Wall, Deflection, Wind Load (IS 875 Part 3)

N

Nickel Sulphide Inclusion

A nickel sulphide inclusion is a tiny particle of nickel sulphide that can form in glass during manufacture. In toughened glass, the particle can slowly change form and expand over months or years, and because the core of toughened glass is in tension, this can cause sudden spontaneous breakage. Heat soak testing reduces the risk by breaking affected panes before installation.

O

Oil Canning

Oil canning is visible waviness or rippling in the surface of flat metal panels such as ACP. It can be caused by thin skins, very large panels, an uneven sub-frame, or fixings that stop the panel expanding freely in heat. It shows most on glossy and metallic finishes in low-angle sunlight. Thicker sheets, correct stiffening and true framing reduce it.

Open Joint

An open joint is a cladding joint left unsealed as a visible groove, instead of being filled with sealant. Because some rain will pass through, the wall behind must be weatherproof and the cavity must be drained and ventilated so water runs out at the base. Open joints avoid sealant streaking and maintenance but need careful design behind the panels.

Related service: ACP Cladding. See also: Weather Sealant, Backer Rod, Flashing

P

Parapet

A parapet is a low wall along the edge of a roof, terrace or balcony. On an elevation it forms the top line of the facade, and it is often clad with ACP as a band and finished with a coping to keep rain out. Parapet tops are where water enters first, so they need well-sealed copings and flashings.

Related service: ACP Front Elevation. See also: Coping, Flashing, Fascia

Patch Fitting

A patch fitting is a metal clamp fixed to the corner of a frameless toughened glass door or panel through holes or notches made before toughening. Bottom patches connect the door to a floor spring and top patches to a pivot, so the door can swing without a frame. Patch fittings are usually stainless steel or aluminium and must suit the glass thickness.

Related service: Toughened Glass. See also: Floor Spring, Toughened (Tempered) Glass, Point-Fixed Glazing

PE Core (Polyethylene Core)

A PE core is the standard ACP core made of solid low-density polyethylene. It is light, easy to route and fold, and lower in cost, so it is widely used for interiors, signage and low-rise work. Polyethylene is combustible, so PE-core ACP is not the right choice where fire spread up a facade is a concern, such as multi-storey and public buildings.

Point-Fixed Glazing

Point-fixed glazing is a frameless glazing method in which glass panes are held only at discrete points, usually near the corners, by bolts or clamps instead of being supported along their edges in a frame. Spider glazing is the best-known type. The glass must be toughened or laminated toughened, with holes made before toughening, and the support structure must be engineered.

Related service: Spider Glazing. See also: Spider Fitting, Articulated Bolt (Routel), Glass Fin, Patch Fitting

Polyester Coating

Polyester coating is a lower-cost paint finish used on ACP and aluminium. It performs well indoors and in sheltered locations, but on sun-facing exteriors it tends to fade and chalk sooner than PVDF coating. It is a sensible choice for interior cladding, signage and shaded areas, and a false economy on west- or south-facing facades in strong sun.

Related service: ACP Cladding. See also: PVDF Coating, Chalking, Aluminium Composite Panel (ACP)

Powder Coating

Powder coating is a finish in which dry paint powder is sprayed electrostatically onto aluminium or steel and then baked in an oven to form a hard, even film. It is the most common finish for aluminium window, partition and curtain wall sections, available in a wide colour range. Durability depends on the powder grade and on proper surface pretreatment.

Related service: Aluminium Partition. See also: Anodising, Aluminium Partition Section, Mullion

Pressure Plate and Cover Cap

A pressure plate is an aluminium strip screwed to a curtain wall mullion or transom that clamps the glass edges against gaskets. A snap-on cover cap then hides the screws, leaving a visible aluminium grid on the outside. This capped system is simpler and more forgiving of site errors than structural glazing, and glass replacement is easier.

Related service: Curtain Wall Glazing. See also: Gasket, Curtain Wall, Structural Glazing, Stick Curtain Wall

PVB Interlayer

PVB (polyvinyl butyral) is the most common interlayer used in laminated glass. It is a tough, flexible plastic film that bonds the glass panes together so the fragments stay in place if the glass breaks. PVB also blocks most UV and improves sound reduction. Its exposed edges should be kept out of standing water, which can affect the bond over time.

Related service: Glass Railings. See also: Laminated Glass, SGP Interlayer, Delamination

PVDF Coating

PVDF coating is a high-performance paint finish based on polyvinylidene fluoride resin, used on exterior ACP and aluminium. It resists ultraviolet light, so colour and gloss last much longer outdoors than with polyester coatings, with slower fading and chalking. PVDF is the recommended coating for sun-facing and coastal facades in Tamil Nadu and Kerala.

Related service: ACP Cladding. See also: Polyester Coating, Chalking, Aluminium Composite Panel (ACP)

R

Reflective Glass

Reflective glass has a thin metallic coating that reflects part of the visible light and solar heat, giving a mirror-like look from outside in daylight. It cuts glare and heat gain and gives daytime privacy. At night, when the interior is lit, the effect reverses and people outside can see in. It is commonly used on commercial facades.

Routing and Folding

Routing and folding is the standard way of shaping ACP. A V- or U-shaped groove is cut along the back of the sheet, removing the back skin and most of the core while leaving the face skin intact, so the panel can be folded by hand into returns, trays and corners. The correct groove depth stops the face skin cracking at the fold.

Related service: ACP Cladding. See also: Cassette System, Aluminium Composite Panel (ACP), Skin Thickness

S

SGP Interlayer

SGP is an ionoplast interlayer for laminated glass, commonly known by the initials of a well-known brand. It is much stiffer and stronger than PVB, so broken laminated glass stays more rigid and in place, and its edges are more stable when exposed. It is preferred for frameless glass railings, glass floors and other structural uses.

Related service: Glass Railings. See also: PVB Interlayer, Laminated Glass, Balustrade

Shop Drawing

A shop drawing is a detailed fabrication and installation drawing prepared by the facade contractor from the architect's design. It shows exact panel sizes, joint positions, aluminium sections, fixings, brackets and junctions with other trades. Shop drawings are reviewed and approved before fabrication starts, and they help catch clashes and measurement errors before material is cut.

See also: Mock-up, Sub-frame, Curtain Wall

Skin Thickness

Skin thickness is the thickness of each aluminium sheet on the faces of an ACP panel, separate from the panel's total thickness. Typical skins are 0.5 mm for exterior facades, 0.3 mm for signage and sheltered areas, and 0.21 mm or thinner for budget interior work. Thicker skins are stiffer and resist dents and waviness better, so ask for skin thickness in writing.

Related service: ACP Cladding. See also: Aluminium Composite Panel (ACP), Oil Canning, Routing and Folding

Soffit

A soffit is the exposed underside of a building element, such as a roof overhang, canopy, porch, balcony or cantilevered floor. A soffit ceiling finishes that underside, usually with ACP or aluminium panels where it is exposed to weather. Exposed soffits must be fixed to resist wind suction and detailed with drip edges so blown rain runs off.

Related service: Soffit Ceiling. See also: Drip Edge, Aluminium Composite Panel (ACP), Sub-frame

Solar Control Glass

Solar control glass is glass that reduces the amount of solar heat entering a building while still admitting daylight, by means of a body tint, a reflective coating or a selective coating. It helps cut air-conditioning loads and glare on sun-facing facades. Its performance is described by figures such as solar factor and visible light transmission on the manufacturer's data sheet.

Spandrel Panel

A spandrel panel is the opaque part of a glazed facade that hides floor slabs, beams, ceiling voids and services between areas of vision glass. It can be ceramic-fritted or back-painted glass, ACP or an insulated panel. Spandrel glass can get very hot because heat builds up behind it, so it is normally heat-strengthened or toughened.

Related service: Curtain Wall Glazing. See also: Ceramic Frit, Heat-Strengthened Glass, Curtain Wall

Spider Fitting

A spider fitting is a stainless steel bracket with one to four arms that holds the corners of frameless glass panes through bolts set in holes drilled in the glass. One four-arm spider typically supports the corners of four neighbouring panes. Spiders mount on a steel, glass-fin or cable structure. SS 304 suits inland sites; SS 316 suits coastal and humid ones.

Related service: Spider Glazing. See also: Articulated Bolt (Routel), Point-Fixed Glazing, Glass Fin, Tea Staining

Stick Curtain Wall

A stick curtain wall is assembled piece by piece on site: mullions are fixed to the building one by one, transoms are fitted between them, and the glass is installed afterwards. It needs less factory set-up and adapts well to site variations, so it suits low- and mid-rise buildings, irregular shapes and smaller facades. Site workmanship largely decides its quality.

Related service: Curtain Wall Glazing. See also: Unitised Curtain Wall, Curtain Wall, Mullion, Transom

Structural Glazing

Structural glazing, or structural silicone glazing (SSG), is a method of fixing glass to an aluminium frame with structural silicone sealant instead of external pressure plates and caps. From outside, the facade reads as smooth glass broken only by thin sealant joints. In 4-sided SSG all edges are bonded; in 2-sided SSG two edges are held by slim caps.

Structural Silicone

Structural silicone is a high-strength silicone adhesive sealant that bonds glass to its aluminium frame and transfers wind load from the glass to the frame in structural glazing. Its bite and thickness are calculated for the wind load and glass size. It needs clean, primed surfaces, compatibility checks with adjacent materials and full curing before the panel is loaded.

Related service: Structural Glazing. See also: Structural Glazing, Weather Sealant, Wind Load (IS 875 Part 3)

Sub-frame

A sub-frame is the secondary framework of aluminium or galvanised steel sections anchored to a wall or structure, onto which ACP, soffit or other cladding panels are fixed. It sets the new facade flat and true even when the wall behind is uneven, and carries wind and panel loads back to the building. Untreated mild steel sub-frames rust, especially in humid areas.

Related service: ACP Cladding. See also: Aluminium Composite Panel (ACP), Cassette System, Oil Canning

T

Tea Staining

Tea staining is light brown surface discolouration on stainless steel, caused mainly by salt and pollutants settling on the surface, especially near the coast. It is largely cosmetic but looks neglected on glazing fittings and railings. Using SS 316 instead of SS 304 in coastal and poolside locations, choosing smoother finishes and washing regularly all reduce it.

Related service: Glass Railings. See also: Spider Fitting, Balustrade

Thermal Movement Joint

A thermal movement joint is a gap designed into a facade to let panels and frames expand and contract with temperature without buckling, cracking or tearing sealant. Aluminium expands noticeably with heat, roughly twice as much as steel, so ACP panels, mullions and fixings need slotted holes, sliding connections or sealed joints sized to absorb the movement.

Toughened (Tempered) Glass

Toughened glass, also called tempered glass, is float glass heated above 600 degrees Celsius and rapidly cooled with air, which puts its surfaces in compression and makes it roughly four to five times stronger than annealed glass. It breaks into small, relatively blunt pieces, so it is a safety glass. It cannot be cut or drilled after toughening.

Transom

A transom is a horizontal framing member in a curtain wall, window or glazed partition, fitted between the vertical mullions. Transoms divide the glass into panels, support the weight of the glass above them and often mark the line between vision glass and spandrel panels. In capped systems, a pressure plate and cover cap run along each transom.

Related service: Curtain Wall Glazing. See also: Mullion, Curtain Wall, Spandrel Panel

U

Unitised Curtain Wall

A unitised curtain wall is made of complete frame-and-glass panels, usually one storey high, that are assembled and glazed in a controlled workshop and then lifted onto anchors on the building. It gives consistent factory quality and closes in tall or repetitive buildings quickly, but needs more upfront engineering, storage space and lifting arrangements than a stick system.

Related service: Curtain Wall Glazing. See also: Stick Curtain Wall, Curtain Wall, Structural Glazing

W

Weather Sealant

Weather sealant is a flexible sealant, usually silicone, used to close the joints between facade panels and around glazing so rain and air cannot get through. It is applied over a backer rod and must stretch and compress as panels move. Unlike structural silicone, it does not hold the glass. It ages with sun exposure, so joints should be inspected yearly.

Related service: ACP Cladding. See also: Backer Rod, Structural Silicone, Thermal Movement Joint, Open Joint

Weep Hole

A weep hole is a small drainage opening in a window, curtain wall frame or sill that lets any water that gets inside the frame drain back to the outside. Weep holes are part of the facade's second line of defence behind the gaskets and sealant. They must be kept clear of dust, debris and paint, because blocked weep holes cause leaks inside.

See also: Gasket, Flashing, Curtain Wall

Wind Load (IS 875 Part 3)

Wind load is the pressure and suction that wind exerts on a building's surfaces. In India it is calculated under IS 875 Part 3, which gives basic wind speeds for each location and factors for risk, terrain, building height and topography. Facade engineers use the result to size glass, mullions, sub-frames, brackets and fixings, especially on tall or exposed buildings.

Related service: Structural Glazing. See also: Deflection, Mullion, Structural Silicone

Sources & standards

Technical statements on this page follow Indian standards and established industry references. Always confirm project-specific requirements with your architect or structural consultant.

Sandwich panel: ACP (aluminium composite panel) — Wikipedia · WikipediaDefinition of aluminium composite panels and their structure.
Tempered glass — Wikipedia · WikipediaDefinition of tempered (toughened) glass and how it breaks.
Laminated glass — Wikipedia · WikipediaDefinition of laminated glass and PVB/SGP interlayers.
Curtain wall (architecture) — Wikipedia · WikipediaDefinition of curtain walls, stick vs unitised systems.
Soffit — Wikipedia · WikipediaDefinition of soffits under eaves, porches and ceilings.
Insulated glazing — Wikipedia · WikipediaDefinition of insulated glazing units (DGU).

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