Plain definitions of the terms that appear on drawings, BOQs and tender documents — what each one means, how it is specified in India, and the mistakes that cost money on site.
The fire rating of an aluminium composite panel is set almost entirely by what sits between its two aluminium skins: a standard polyethylene core burns readily, an FR (fire-retardant) core is mineral-filled to resist ignition, and an A2 core is mineral enough to be classed as limited-combustibility.
Anodising grows a hard oxide layer out of the aluminium itself by electrolysis; powder coating sprays a polymer onto the surface and bakes it on. One is part of the metal, the other sits on top of it — which is why they age in completely different ways.
Carpet area is the usable floor you can actually lay carpet on; built-up area adds the walls; super built-up (or chargeable) area adds a share of lobbies, lifts, staircases and services. Rent is usually quoted on super built-up, while fit-out is priced on carpet — which is why the two numbers must never be mixed up.
Cat A is the landlord's base finish — a blank, serviced but unusable floor with ceiling, lighting, basic HVAC and raised floor. Cat B is the tenant's build on top of it: the layout, cabins, meeting rooms, branding and everything that makes the space specific to one occupier.
A double glazed unit is two panes of glass separated by a sealed, dried air or argon cavity held apart by a spacer bar. The cavity is what insulates; the edge seal is what keeps the cavity dry, and when that seal fails the unit fogs permanently.
A facade mock-up is a full-size sample of the actual system — real profiles, real glass, real seals — built and tested before the facade goes into production, so that appearance and performance are proven on a few square metres rather than discovered across the whole building.
A rainscreen ventilated facade hangs an outer skin of panels in front of an insulated, weatherproofed wall with a deliberate air gap between them. The outer panel sheds most of the rain; the drained and ventilated cavity behind handles whatever gets past it.
A raised access floor is a grid of removable panels sitting on adjustable pedestals above the structural slab, creating a shallow service void for power, data and sometimes air — so cabling can be rerouted later by lifting a tile rather than opening a ceiling.
Solar Heat Gain Coefficient is the fraction of solar radiation striking a glazed unit that ends up as heat inside the building — an SHGC of 0.25 means a quarter of the sun's energy gets through. In a hot climate it is the single most important number on a glass specification.
Spandrel glass is the opaque glazing used to conceal the floor slab, ceiling void and services between one floor's vision glass and the next, so a facade reads as continuous glass from outside.
Spider glazing supports glass on stainless-steel arms — spiders — bolted through holes drilled in the panel corners, so the glass is carried at points rather than along its edges. Removing the frame is what makes an atrium or lobby read as glass with almost nothing holding it up.
Structural silicone glazing uses a load-bearing silicone sealant to bond glass directly to its supporting frame, so wind load transfers through the adhesive rather than through mechanical clamps — which is what allows a facade to read as flush glass with no visible framing outside.
A thermal break is an insulating strip — usually polyamide — bonded between the inner and outer halves of an aluminium profile, so heat cannot conduct straight through the frame. Without it, the frame is a continuous metal bridge between outside and inside.
A unitized curtain wall is a glazed facade delivered as complete factory-assembled panels — glass already set into its frame — which are lifted into place and locked to the building floor by floor, rather than being built up from separate components on site.