61 terms that come up on glazing jobs in New York, each in a few sentences with a link to the page that goes deeper. Written by us, in the plain meaning we use on site and in our quotes; more are added as they come up.
A · B · C · D · F · H · I · J · K · L · M · N · P · R · S · T · U · W
A
Annealed glass — Ordinary float glass, cooled slowly. Can be cut and drilled; breaks into large sharp shards; not safety glazing.
More → Argon fill — An inert gas sealed in the cavity of an insulated unit in place of air; conducts less heat and lowers the U-factor. Cannot be used where the unit breathes through a capillary tube.
More → AW rating (Architectural Window) — The highest of the four NAFS/AAMA performance classes for windows and doors — R (residential), LC (light commercial), CW (commercial), AW (architectural). AW units are tested to the heaviest wind, water and structural loads, plus life-cycle and thermal-movement tests; the 461 East New York windows are AW80, meaning AW class at a design pressure of 80 psf.
More → B
Base shoe — A continuous aluminum channel that a frameless glass railing panel sits in, fixed to the slab or stringer.
More → Brick-to-brick — Window replacement that removes the old frame to the masonry opening and sets a new full frame. Restores the whole opening; required by Landmarks on street facades.
More → C
Capillary tube — A thin breather tube in an insulated unit that equalises pressure with altitude; used on wide units such as blinds-between-glass. Rules out argon fill.
More → Casement — A side-hinged window that swings outward on a crank or push; seals by compression on four sides.
More → Cladding (clad wood) — A factory-finished aluminum or fiberglass skin on the exterior of a wood window so the outside never needs paint.
More → Continuous (piano) hinge — A hinge the full height of a door, geared or pin type, that carries the door along its whole edge; used on high-traffic storefront doors to prevent sag and to close the finger-pinch gap on the hinge side.
More → Curtain wall — An aluminum-and-glass exterior wall hung from the floor slab edges, spanning multiple storeys; engineered for wind load and drained at every horizontal.
More → Curtain wall gasket, exterior (after the glass) — The gasket carried on the pressure plate that presses against the outside face of the glass when the plate is bolted on; the outer weather seal. Water that passes it is drained inside the system.
More → Curtain wall gasket, interior (before the glass) — The EPDM gasket set into the face of the mullion that the glass is placed against from outside; the inner air and water seal. Also called the back or setting gasket.
More → Curtain wall jamb filler (perimeter filler) — The aluminum closure piece at the jamb, head or sill where the curtain wall meets the wall or slab; it closes the system, receives the perimeter sealant and flashing, and allows for building movement.
More → Curtain wall mullion — The vertical aluminum member of a curtain wall, anchored to the floor slabs, that carries the glass weight and the wind load down to the structure. The horizontals between mullions are transoms.
More → Curtain wall pressure plate — The exterior aluminum bar bolted through the mullion or transom that clamps the glass against the interior gasket, covered by a snap-on cap. Structural-glazed systems replace it with silicone.
More → D
Daylight opening (DLO) — The visible glass area inside the frame and stops; the number that decides how much light a window actually admits.
More → Double-hung — A window with two sashes that slide vertically past each other on balances; the traditional New York window and the usual Landmarks approval.
More → F
Frameless (shower or railing) — Thick tempered or laminated glass held by hinges, clips, spigots or a base shoe, with no frame around the edges.
More → H
Heat-soaked glass — Tempered glass that has been through a destructive oven test (EN 14179) to provoke nickel-sulphide breaks in the factory rather than on the building.
More → Heat-strengthened glass — Glass cooled at a controlled rate to about twice the strength of annealed; breaks into large pieces that stay in the frame; not safety glazing.
More → I
IGU (insulated glass unit) — Two or more lites sealed around a spacer with a dry cavity between; the standard modern window glass.
More → Installation clips (window anchor clips) — Steel or aluminum clips fixed to the outside of a window frame and screwed to the structure to anchor the unit in the opening; they let the frame be fastened without screwing through the frame itself, keeping the thermal break and the seal intact.
More → Interlayer — The plastic sheet bonded between the lites of laminated glass: PVB for most work, SGP where stiffness and edge stability matter.
More → J
Jamb — The vertical side member of a window or door frame, or of the opening it fits into. The head is the top, the sill the bottom; the jamb carries the hinges or the sash track and receives the perimeter seal.
More → Juliet balcony — A guard fixed directly in front of a full-height window that opens inward, with no walkable balcony behind it.
More → K
Krypton fill — An inert gas denser than argon, sealed in the cavity of an insulated unit; it insulates better than argon in a narrow cavity (about 8–10 mm), which is why it appears in thin triple units and in vacuum-adjacent designs. Far more expensive than argon and rarely worth it in a standard 16 mm cavity, where argon performs nearly as well.
More → L
Laminated glass — Two or more lites bonded with an interlayer; safety glazing; stays in one piece when broken; damps sound; blocks UV.
More → Landmarks (LPC) — The NYC Landmarks Preservation Commission, which reviews any change visible from the street on a landmarked building or in a historic district, including windows.
More → Local Law 97 — NYC’s building carbon law; buildings over 25,000 sq ft report emissions, and window performance data goes into the compliance file.
More → Low-E coating — A microscopically thin metallic coating on a glass surface that reflects heat while passing light; the main driver of a window’s energy performance.
More → Low-iron glass — Float glass with the iron oxide reduced so it has no green cast; Starphire is one brand. Used for thick glass, railings, showers and mirrors.
More → M
Masonry opening (MO) — The hole in the wall, measured brick to brick; the largest of the four window dimensions.
More → Muntin / divided lite — The bar that divides a window into smaller panes. True divided lites are separate pieces of glass; simulated divided lites are bars applied to one lite, with a spacer bar between the glass for Landmarks approval.
More → N
NFRC — The National Fenestration Rating Council; its label on a window gives the tested U-factor, SHGC and visible transmittance.
More → P
Pocket (insert) replacement — A new window fitted inside the old frame, which stays in the wall. Cheaper and faster than brick-to-brick; loses glass area and keeps the old frame’s leaks.
More → Post railing system — A glass guard with vertical posts at intervals — stainless or aluminum — that carry the load, with glass panels clamped or channelled between them. The most economical glass railing and the easiest to engineer; spigot, base-shoe and standoff systems are the post-free alternatives.
More → PVB — Polyvinyl butyral, the standard laminated-glass interlayer.
More → R
Receptor (window receptor system) — A U-shaped aluminum channel fixed to the opening at the head and jambs that a window frame slides into, allowing the unit to be installed from inside, absorbing tolerance, and taking up building movement. Standard on commercial and multifamily replacement.
More → Rough opening (RO) — The framed opening the window unit fits into, smaller than the masonry opening and larger than the unit.
More → S
Saddle (threshold) — The sill piece of a door opening that the door closes against or over: an aluminum saddle on a storefront door (low, ADA, not weathertight), a weathered sill with gaskets and drainage on a terrace door. Interior saddles are often stone or marble.
More → Safety glazing — Glass that meets ANSI Z97.1 / CPSC 16 CFR 1201: tempered or laminated. Required at doors, sidelites, showers, railings and glass near the floor.
More → SGP (SentryGlas) — A stiff ionoplast laminated-glass interlayer; the standard for frameless railings because a broken panel stays standing.
More → SHGC — Solar heat gain coefficient: the fraction of solar heat a window lets through. Low on a south or west face; higher where winter sun is wanted.
More → Shower hinge, glass-to-glass (180°) — A hinge that joins a swinging door to a fixed glass panel in the same plane, with no wall or post at the hinge side; both leaves clamp glass.
More → Shower hinge, glass-to-glass 90° — A hinge that joins a door to a fixed panel at right angles, for a corner enclosure where the door hangs off the return panel rather than the wall.
More → Shower hinge, wall-to-glass — A frameless shower door hinge with one leaf bolted through the tile into the wall and the other clamped to the glass; the standard hinge, and the one that needs solid backing behind the tile.
More → Sightline — The width of frame visible from outside. Slim sightlines are the point of steel-look aluminum systems such as Reynaers SlimLine 38.
More → Spandrel glass — Opaque glass in the same frame as vision glass, used to hide a floor slab or wall so a facade reads as one plane.
More → Spigot — A short stainless post that grips the bottom edge of a glass railing panel; a near-frameless system.
More → Storefront — A one-storey aluminum framing system that sits on the ground-floor slab and fills a retail or lobby opening.
More → Structural glazing — Glass bonded to the mullions with structural silicone so no frame shows on the exterior.
More → T
Tempered glass — Glass cooled fast to about four times annealed strength; breaks into small blunt cubes; safety glazing; cannot be cut after processing.
More → Thermal break — A polyamide strut joining the inner and outer halves of an aluminum profile so heat cannot cross the frame. Every aluminum window worth buying has one.
More → Tilt-and-turn — A window whose single sash tilts in at the top for ventilation or swings fully into the room; the European standard, with a four-sided compression seal.
More → Trickle vent — A small closable slot through a window frame, usually at the head, giving continuous background ventilation with the window locked; standard on tight new buildings to control condensation.
More → Triple glazing — An insulated unit with three lites and two cavities; the best thermal performance, at more weight and thickness.
More → U
U-factor — The rate of heat loss through a window; lower is better. The NFRC number an energy code sets a limit on.
More → uPVC — Unplasticised PVC, the rigid plastic used for multi-chamber window frames; the best thermal performance per dollar.
More → W
Warm-edge spacer — A low-conductivity spacer between the lites of an insulated unit; keeps the glass edge warmer and reduces condensation at the perimeter.
More → Weep hole — A small drain through a sill that lets water that gets past the gaskets out. Painted or caulked shut, it is the commonest cause of a leaking storefront.
More → Window guard / limiter — A device that stops a window opening more than 4½ inches, required by NYC on windows in apartments where a child under 11 lives; a key-locking handle on a tilt-and-turn is one form.
More → What is the difference between tempered and laminated glass?
Tempered is heat-treated to break into small blunt cubes; laminated is two lites bonded with an interlayer so it stays in one piece. Both are safety glazing; laminated is required where a broken pane must stay in place, such as railings.
What does brick-to-brick mean?
Removing the old window frame to the masonry and installing a new full frame, as opposed to a pocket replacement inside the old frame. Landmarks requires it on street facades.
What does an AW rating mean?
Architectural Window: the highest NAFS/AAMA performance class, tested to the heaviest wind, water and structural loads plus life-cycle tests. AW80 means AW class at a design pressure of 80 psf.
About this page. Written by Alex GC Inc. d/b/a Alex Glass Construction and reviewed before publication by Aleksandr Chernovolenko, Managing Partner, with our design and estimating lead and a field foreman. Our foremen hold the NYC DOB Site Safety Training supervisor card and our crews the 40-hour worker card; we are certified to fabricate, install and service Alutech and Everest aluminum systems. Facts are drawn from our own projects, manufacturer test data and the applicable codes; where we are giving an opinion, we say so. Last reviewed September 2026. Credentials
