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Aluminum Window Glass Selection Guide
Glass Specification Guide
How to specify, quote and inspect glazing
This guide answers three questions only: which glazing a project needs, what a quotation must state, and how to inspect the delivery on site. Every technical statement is followed by a plain-language line.
Three conventions before you read
Every statement below is one of three kinds; the label tells you how far it can be relied on — a cited standard, a mainstream practice, or a judgement we are willing to discuss.
Standards and terms
Cited by number: GB/T 2680-2021, GB/T 15763 series, JGJ 113-2015, EN 12150, AS 1288. These are verifiable provisions: we quote them, we do not rewrite them.
Industry practice
Double-silver Low-E + argon + warm edge. Mainstream, not the only answer.
Judgement, labelled
Where no standard settles the question, we say so and give our reasoning. Nothing here is a promise without a report behind it.
Specification in three steps
Step one is where mistakes start: market and scenario are two different axes and must be split.
STEP 1A
Market: compliance, aesthetics and baseline glazing
The market sets the floor — which certification applies, which safety glazing rules apply, what the default look is.
| Market | Typical demand | Baseline | Compliance | Safety glazing |
|---|---|---|---|---|
| Europe | Thermal performance first, slim sightlines and clear views. | Double-silver Low-E + argon + warm edge; triple glazing with two cavities is common in northern Europe. | CE / EN 14351-1; EN 1279; EN 12150. | EN 12150 for tempered glass and EN ISO 12543 for laminated glass; required at low-level glazing, doors and balustrades. |
| North America | Whole-window label values and consistent glazing divisions. | Dual-pane Low-E + argon as standard; triple glazing as an option. | NFRC labels; AAMA; coastal ASTM E1886 / E1996 and TAS 201/202/203. | 16 CFR 1201 Cat I / II; mandatory at low-level glazing, doors and bathrooms. |
| Middle East | Shading, resistance to sand and dust, and low reflection. | Double- or triple-silver Low-E + argon; consider laminated glass for large lites. | ASTM and EN are often mixed — align with the tender documents. | Per tender; tempered + laminated glass advised for large lites and low-level glazing. |
| Southeast Asia | Heat and humidity, moisture protection and insect protection. | Single- or double-silver IGU; upgrade hardware and edge seals on the coast. | Project-defined, with EN / AS references; Singapore has mandatory registration. | Per project specification; safety glazing at low-level glazing, doors and bathrooms. |
| Japan / Korea | Precision, airtightness and acoustics. | Double-silver Low-E + highly airtight framing; asymmetric laminated glass for demanding acoustic requirements. | JIS / KS are not fully interchangeable with GB and EN. | Follow JIS / KS; the approach to glazing locations is similar to EN. |
| Australia / New Zealand | WERS ratings, UV resistance and insect screens. | Low-E IGU + laminated glass at safety locations; dark tints are widely accepted. | AS 2047; AS 1288; WERS. | AS/NZS 2208 Grade A/B; mandatory at low-level glazing, doors, balustrades and bathrooms. |
| South America | Price sensitivity and complex customs clearance. | Start with single-silver Low-E or plain IGU, then upgrade for the project. | Significant differences between countries, including Brazil, Chile and Peru. | Follow the project country’s code; safety glazing at low-level glazing, doors and balustrades. |
| Africa | Weather resistance, wind and sand resistance, and straightforward maintenance. | IGU + single- or double-silver Low-E; use self-cleaning and switchable glass cautiously in dusty areas. | EN or the former colonial power’s standards are often referenced. | Per project specification; tempered + laminated glass advised for large lites and low-level glazing. |
Baseline only, not a mandate. Australia and South America are smaller shares for us today, but their compliance differences are the widest — exactly where a specification-led offer wins.
STEP 1B
Climate and risk: what this elevation needs
The market sets the minimum; the scenario sets this elevation. In the same city, different wind, noise and sun call for different glazing.
| Scenario | Real risk | Action | Inspect |
|---|---|---|---|
| Typhoon / hurricane coast | Windborne debris penetration and failure of the entire window. | Thicker laminated glass + tempered glass, combined where needed; upgrade hardware and anchorage at the same time. | Impact report and classification; anchorage; glass edge bite. |
| Street / rail / airport | Low-frequency noise; increasing thickness alone is ineffective. | Asymmetric thicknesses + laminated glass + IGU, such as 8 + 1.14PVB + 6 + 12A + 6. | Rw / STC reports; measurements of the operable window; listening assessment on site. |
| High altitude / strong UV | Interlayer and seal ageing. | UV-blocking laminated glass + Low-E; avoid exposed organic films. | UV data; interlayer brand; warranty. |
| Severe cold / heavy snow | Edge condensation, stress and snow loads. | Triple glazing with two cavities or wider-cavity double glazing + warm edge + argon; move the coating position inward. | Edge temperature; warm-edge spacer type; Ug report. |
| Hot, arid desert | Thermal stress and spontaneous breakage. | Heat-soaked tempered glass; avoid dark, heat-absorbing large lites; laminate where needed. | Heat-soak records; stress calculations; edge finishing. |
| Hot, humid and rainy | Moisture entering the cavity, mould and corrosion. | Dual seal + quality desiccant; upgrade edge construction. | Sealant brand; production date; transport protection. |
| Coastal salt spray | Accelerated ageing of hardware and seals. | Design glass for wind loads and windborne debris, with particular attention to upgrading hardware coatings. | Salt-spray tests; stainless-steel grade; drainage. |
| High-rise / large lites | Wind-pressure deflection, lifting and replacement cost. | Calculate allowable area under JGJ 113 / AS 1288; use tempered or laminated glass. | Thickness and area schedule; lifting plan; spare-pane ratio. |
Safety glazing locations
“Safety glazing location” is not a product. It is a rule about where safety glass must be used — and it decides whether a quotation needs an extra line and whether the site inspection passes.
Breaks into granules, but can fall
4–5× stronger than annealed; breaks into blunt granules so cut risk is low, but it still leaves the frame.
Broken fragments stick to the interlayer and stay in place
Two panes bonded by PVB or SGP; fragments stay attached. Best for fall prevention, security and acoustics.
In one line: Temper where people can hit it; laminate where broken glass must not fall and injure people; use both where both risks exist.
Four questions
- Can people hit it? Low sills, beside corridors, and door zones.
- Can it fall after breaking? Overhead glazing, rooflights, canopies, balustrades, and high-rise outward-opening windows.
- Are there crowds or water? Bathrooms, swimming pools, and public entrances.
- Does the area or height exceed the limits? Large, extra-tall, or shaped panes.
| Location | Main risk | Common practice | Quotation wording |
|---|---|---|---|
| Floor-to-ceiling / low-sill windows | Human impact and children colliding | Tempered, or tempered + laminated | Low-level: tempered ☐ / laminated ☐ |
| Glass doors, including automatic doors | Impact and falling fragments after breakage | Tempered; laminated is recommended in public buildings | Door leaf: tempered ☐ / laminated ☐ / marking ☐ |
| Bathrooms and shower screens | Slipping, falling and impact | Tempered; laminated is recommended beside a bathtub | Wet area: tempered ☐ / shatter-resistant film ☐ |
| Stairwells, balustrades and balconies | Falling — the most serious consequence | Laminated; tempered + laminated where necessary | Balustrade: laminated ☐ / interlayer ___ mm |
| Overhead glazing, rooflights and canopies | Falling glass and fragments from above | Laminated, as required by most codes | Overhead: laminated ☐ / fall-protection class ☐ |
| Curtain walls and observation-lift enclosures | Falling from height and thrown objects | Follow the system design; often IGU + laminated | Curtain-wall panel: build-up schedule reference ___ |
| Public entrances and lobbies | Dense foot traffic and a high likelihood of impact | Tempered + laminated preferred | Public area: enhanced configuration ☐ |
| Oversized, shaped or drilled panes | Stress concentration, spontaneous breakage and replacement cost | Heat-soaked tempered; laminated where necessary | Large pane: heat-soaked ☐ / stress calculation ☐ |
Final locations and size thresholds follow the local code: GB 15763 series and JGJ 113-2015 in China, EN 12150 / EN ISO 12543 in Europe, AS 1288 and AS/NZS 2208 in Australia and New Zealand, 16 CFR 1201 in the United States.
Acoustics and special requirements
Acoustics is the easiest promise to write and the easiest to break on site. Ask three questions, then state one boundary.
Where does the noise come from?
Road traffic, rail, airports or construction. Use laminated glass for predominantly low-frequency noise; thicker insulating glazing can address mid- to high-frequency noise.
When is it loudest?
Noise tolerance is lowest at night. Go one class higher for projects sensitive to night-time noise.
What level is acceptable?
Set the indoor target first, for example ≤ 40 dB(A), then work back to the required Rw.
Build-up formula
Acoustics = mass + damping + decoupling. In a quotation it becomes five writable parameters: total thickness, thickness asymmetry, interlayer thickness, cavity depth, opening type.
One line per special requirement
Fire, ballistic, security, bird-safe, blast and hurricane resistance each have their own standards and test methods. Never merge them into “reinforced glass”. Write one line for each: need → standard → class → report number.
Glazing type atlas
Six groups, twenty-three types, covering what the Chinese supply chain delivers reliably. Three columns each: how to write it, how to explain it, where it goes wrong.
A. Substrate
| Type | Technical description | In plain language | Where it goes wrong |
|---|---|---|---|
| Float glass | GB 11614; uniform thickness and low optical distortion; the base glass for further processing. | The most ordinary glass; all processing starts here. | Poor base-glass quality leads to colour differences and ripples after coating. |
| Low-iron glass | Very low iron content gives high transmittance and removes the green cast. | Whiter and clearer at the same thickness, without a green tint. | For white interiors and large panes, omitting low-iron glass can lead to rework costing far more than the price difference. |
B. Strengthening
| Type | Technical description | In plain language | Where it goes wrong |
|---|---|---|---|
| Tempered glass | GB/T 15763.2-2025 (effective 2026-08-01); approximately 4–5× strength, with granule breakage; requires CCC and tempered-glass markings. | Resists breakage; when it breaks, it forms small granules. | There is a risk of spontaneous breakage; no subsequent cutting or drilling. |
| Heat-soaked tempered glass | Heat-soak treatment to GB/T 15763.4 triggers nickel-sulphide phase-change breakage in advance. | An early “landmine check” for tempered glass. | Not every configuration receives this treatment, and it does not mean zero spontaneous breakage. |
| Heat-strengthened glass | Strength lies between annealed and tempered glass; it breaks into large pieces and is generally not treated as safety glass. | Stronger than ordinary glass, but still breaks into large pieces. | Often described verbally as “tempered”; checking the marking exposes the difference. |
C. Laminated and composite
| Type | Technical description | In plain language | Where it goes wrong |
|---|---|---|---|
| PVB laminated glass | GB/T 15763.3-2025 (effective 2026-08-01); interlayer thickness in multiples of 0.38 mm: 0.76 / 1.14 / 1.52 / 2.28. | Two glass panes sandwich a film; broken fragments stick to it and do not fall away. | Saying only “laminated” without the interlayer thickness can hide several classes of difference in acoustic and security performance. |
| SGP interlayer | Stiffer than PVB and less prone to softening when heated; used for facades, balustrades and oversized panes. | Harder and more heat-resistant than an ordinary interlayer. | More expensive; the quotation must state “PVB or SGP”. |
| Wired glass | Metal wire mesh inside the glass provides decoration and some security and fire resistance. | Wire netting inside the glass. | Cannot be used as structural safety glass; optical quality is limited. |
| Ballistic glass | A multilayer composite classified to EN 1063 / UL 752. | Classified by the firearm threat it can stop. | Without a classification certificate, the ballistic claim amounts to nothing. |
D. Insulating units: cavities, gases and spacers
| Type | Technical description | In plain language | Where it goes wrong |
|---|---|---|---|
| Insulating glass unit (IGU) | GB/T 11944; panes separated by a spacer with a dual seal, desiccant, and dry air or inert gas in the cavity. | Two panes enclose an air layer; that layer provides insulation. | Without gas filling or a coating, it is simply an extra air cavity, not energy-performance glass. |
| Argon filling | Argon (or krypton) reduces heat conduction through the gas; krypton suits narrow cavities. | Replace the air with a “lazier” gas. | It leaks slowly, so performance degrades after several years. |
| Warm-edge spacer | Stainless-steel composite, glass fibre or silicone foam, with lower linear thermal transmittance than an aluminium spacer. | The ring around the glass: the less heat it conducts, the better. | Aluminium spacers are prone to condensation at edges and corners. |
| Triple glazing | Three panes and two cavities give better U-value and acoustics than double glazing, with greater weight and higher hardware requirements. | Three panes and two air layers: better insulation, but heavier. | Triple glazing with squeezed cavities may perform worse than double glazing with a wider cavity. |
| Vacuum glazing | An evacuated cavity is held apart by support pillars; heat transfer is mainly by radiation. | Remove the air between the panes. | High cost, size limits and a fragile edge seal. |
| IGU with an integral blind | A blind inside the cavity, operated magnetically or electrically. | A blind fitted between two glass panes. | Components inside the cavity affect sealing and the warranty. |
E. Coatings
| Type | Technical description | In plain language | Where it goes wrong |
|---|---|---|---|
| Offline Low-E (soft coat) | Within GB/T 18915.2; magnetron-sputtered silver in single-, double- or triple-silver layers. The fragile coating must be used within a glazing unit. | A vacuum-deposited silver coating: the best performance, but delicate. | A coating installed on the wrong surface can lose a performance class without any visible sign. |
| Online Low-E (hard coat) | A high-temperature coating applied on the float line; firmly bonded, usable as a single pane and temperable, with slightly lower performance. | A coating fired into the glass: tough, but slightly less efficient. | Sometimes sold at a soft-coat price; ask whether it can be used as a single pane to distinguish it. |
| Solar-control coated glass | Within GB/T 18915.1; reflection reduces heat gain, with high visible-light reflectance. | Reflects heat and light away like a mirror. | Extensive residential use can cause light pollution and dark interiors. |
| Ceramic-frit glass | Ceramic enamel is printed and fired during tempering, giving stable colour and allowing patterns. | Colour fired onto glass, so it does not fade. | Blocks light and increases heat absorption; the design must be finalised before tempering. |
F. Functional glass
| Type | Technical description | In plain language | Where it goes wrong |
|---|---|---|---|
| Fire-resistant glass | GB 15763.1; A: insulating / B: partially insulating / C: non-insulating. Requires a fire-rated frame and hardware. | Stopping flames and stopping both flames and heat are two different things. | Class C cannot serve as insulating glass; without a fire-rated frame, the whole-window rating does not hold. |
| Self-cleaning glass | A hydrophilic surface coating uses UV to break down dirt and rain to wash it away. | Rain helps it clean itself, but it still needs washing. | Performance is reduced in shaded or low-rainfall locations. |
| Switchable glass (PDLC) | A liquid-crystal film is laminated inside: clear when powered, frosted when unpowered. | Press a switch and the glass turns frosted. | Poor outdoor weather resistance; power supply and maintenance are required. |
| Patterned / frosted glass | A rolled pattern, surface etching or sandblasting. | You cannot see clearly through it, but silhouettes remain visible. | Do not judge only a close-up sample; check the effect from 1 metre away. |
Metrics and typical values
Why the same glass shows different numbers in different markets: one is the glass centre, the other the whole window. We quote Uw first, Ug as a footnote.
| Metric | Definition | In plain language | Common misuse |
|---|---|---|---|
| Uw | Whole-window heat transfer coefficient, including frame, edges and installation: W/(m²K)BTU/(h·ft²·°F). Lower means better insulation. | How well the complete window insulates — what the customer actually buys. | Advertising one Uw value for different frame systems. |
| Ug | Glass-centre heat transfer coefficient: W/(m²K)BTU/(h·ft²·°F). | How well the glass alone insulates. | Quoting Ug as Uw. |
| SHGC / g | Solar heat gain coefficient, 0–1; lower means stronger solar control. Called the g-value in Europe. | How much of the sun’s heat enters. | Assuming lower is always better; in northern regions, it can make the space colder. |
| VT | Visible light transmission, 0–1. | How much daylight gets through. | Looking at VT without considering LSG. |
| LSG | Light-to-solar-gain ratio = VT / SHGC. | Blocking heat without making the room too dark. | Rarely discussed, yet considered in high-end projects. |
| Rw / STC | Sound reduction in dB: Rw to EN ISO 717-1; STC to ASTM E90. Not interchangeable. | How much noise is blocked. | Quoting glass Rw as the acoustic performance of the whole window. |
| Thickness | mminch; 1 inch = 25.4 mm. Applies to glass and cavities. | Glass thickness affects acoustics and strength. | Writing “6+12+6” without stating the units. |
Typical ranges by build-up
These are mid-range judgements of common industry values for early discussions and selection. Contracts and acceptance must rely on test reports.
| Build-up | Ug | SHGC | VT | LSG |
|---|---|---|---|---|
| 6 + 12A + 6 clear IGU | 2.7–2.9 W/(m²K)0.48–0.51 | 0.70–0.78 | 0.79–0.82 | 1.0–1.1 |
| + Single-silver Low-E + argon | 1.4–1.6 W/(m²K)0.25–0.28 | 0.35–0.45 | 0.65–0.75 | 1.5–1.9 |
| + Double-silver Low-E + argon | 1.1–1.3 W/(m²K)0.19–0.23 | 0.25–0.35 | 0.60–0.70 | 1.8–2.3 |
| + Triple-silver Low-E + argon | 1.0–1.2 W/(m²K)0.18–0.21 | 0.20–0.28 | 0.55–0.65 | 2.1–2.6 |
| Triple glazing, two cavities + two Low-E coatings + argon | 0.6–0.8 W/(m²K)0.11–0.14 | 0.25–0.35 | 0.55–0.65 | 1.8–2.3 |
| Whole-window reference (thermally broken aluminium) | 1.2–1.6 W/(m²K)0.21–0.28 | 0.25–0.40 | 0.55–0.70 | 1.6–2.2 |
Conversion: 1 W/(m²K) ≈ 0.176 BTU/(h·ft²·°F); 1 BTU/(h·ft²·°F) ≈ 5.68 W/(m²K); 1 inch = 25.4 mm. Only the three tables carrying values in both unit systems have an SI / IP switch at the top right; tables without units have none.
Quotation and site acceptance
A specification page does not publish prices. It publishes what can be checked — so the client believes the numbers before the first invoice.
6.1 Nine points a quotation should cover — not a mandatory form
These nine are dimensions to think through, not rows you must fill. One window may compress them into a single line; a whole building may split them per unit. What clients care about is whether the questions got answered, not whether the grid is full.
The diagram groups these nine points into five groups. The first four — location and size, build-up, performance, and standards with report numbers — make a quotation verifiable and usually appear in writing. The level of detail for the other points depends on project size and client requirements.
| # | Field | Example wording | What it answers |
|---|---|---|---|
| 1 | Substrate type and thickness | Low-iron float 6 mm0.24 in | Clarity and processing limits. |
| 2 | Tempered / heat-soaked | Tempered + heat-soaked (GB/T 15763.2-2025 / GB/T 15763.4) | Safety class and spontaneous breakage risk. |
| 3 | Laminating interlayer | PVB 1.14 mm0.045 in (multiples of 0.38 mm) | The actual level of acoustic and security performance. |
| 4 | Cavity and gas | 12 mm0.47 in, argon fill ≥ 90% | Insulation capability and expected deterioration. |
| 5 | Low-E coating system and surface | Double silver, surface 2 | One surface wrong, one performance class lost. |
| 6 | Spacer | Warm edge, stainless-steel composite | Edge condensation and durability. |
| 7 | Uw (with Ug) | Uw 1.4 W/(m²K)Uw 0.25 BTU/(h·ft²·°F); Ug as a footnote | The central value customers use to compare quotations. |
| 8 | SHGC and VT | SHGC 0.28 / VT 0.62 | The balance between solar control and daylight. |
| 9 | Rw and test standard | Rw 38 dB (EN ISO 717-1, report no. ___) | The basis for an acoustic-performance promise. |
The example values illustrate the wording only; replace them with test-report values in a real quotation.
Rows can be combined: small projects can put the build-up and performance on the same line; larger projects can split them per window and include a summary table on the first page. The format serves verifiability, not filling every cell.
6.2 A safety glazing clause in every quotation
The same clause applies across all eight markets; only the reference standard changes. Australia and South America are included on the same footing as Europe and North America.
| Market | Clause reference | Quotation wording |
|---|---|---|
| Europe | EN 12150 (tempered); EN ISO 12543 (laminated) | “Safety locations to EN 12150 / EN ISO 12543.” |
| North America | 16 CFR 1201 Cat I / II; coastal ASTM E1886 / E1996 | “Safety locations to 16 CFR 1201; impact resistance to ASTM E1886 / E1996.” |
| Middle East | Tender documents, commonly referring to EN / ASTM | “As required by the tender; where unspecified, to EN 12150 / EN ISO 12543.” |
| Southeast Asia | Project specification + EN / AS references | “Per project specification; EN 12150 / EN ISO 12543 as the default reference.” |
| Japan / Korea | JIS / KS safety-glazing requirements | “To JIS / KS, with an explanation of the test methods attached.” |
| Australia / New Zealand | AS/NZS 2208 Grade A / B; AS 1288 locations and areas | “To AS/NZS 2208 Grade A/B and AS 1288.” |
| South America | Project-country code; where no clear code applies, EN 12150 / EN ISO 12543 | “To the project-country code, with the reference standards listed in the contract annex.” |
| Africa | EN or the project-specified standard | “Per the project-specified standard.” |
6.3 Five site checks
- Markings: Check that the CCC (3C) and tempered-glass markings are complete.
- Spacer: Aluminium or warm edge can be distinguished at a glance.
- Edge seals: Check that the dual seals are flat, with no bubbles or gaps.
- Cavity: Check the gas fill using markings or reports, and check for desiccant.
- Coating position: Count the reflected flame images to identify which surface carries the coating.
The client can finish all five checks without dismantling the frame. Completing them before sign-off prevents most common post-delivery disputes.
Standards referenced
Listed for verification, not decoration.
China
GB 11614 — Flat glass
GB/T 11944 — Insulating glass units
GB 15763.1 — Fire-resistant safety glazing
GB/T 15763.2-2025 — Tempered glass
GB/T 15763.3-2025 — Laminated glass
GB/T 15763.4 — Heat-soaked tempered glass
GB/T 18915.1 — Solar-control coated glass
GB/T 18915.2 — Low-E coated glass
GB/T 2680-2021 — Measurement of glass transmittance and related parameters
JGJ 113-2015 — Technical specification for application of architectural glass
GB/T 15763.2-2025 and GB/T 15763.3-2025 both take effect on 1 August 2026, replacing the earlier GB 15763.2.
International
EN 12150 — Tempered glass
EN ISO 12543 — Laminated glass
EN 1279 — Insulating glass units
EN 14351-1 — Windows and doors
EN ISO 717-1 — Acoustic rating
EN 1063 — Ballistic resistance
EN 356 — Security glazing
ASTM E90 — Airborne sound transmission
ASTM E1886 / E1996 — Impact resistance
16 CFR 1201 — Safety glazing
NFRC — Whole-window rating
AS 1288 — Glass in buildings
AS/NZS 2208 — Safety glazing
AS 2047 — Windows
WERS — Energy rating