Applications
HOME < Applications
Introduction: The Cost of Choosing the Wrong Transparent Material
A single glass panel failure in a commercial skylight costs an average of USD 4,800 in emergency replacement, cleanup, and business interruption — not counting liability if glass shards injure occupants (EN 12600 Class 2B). When procurement teams specify transparent materials for architectural glazing, machine guarding, vehicle windows, or greenhouse roofing, they are making a long-term cost decision disguised as a material selection. Glass is cheap upfront. Polycarbonate is cheap over the asset lifecycle. This guide provides technical data, international standard references, and a procurement framework that engineers and B2B buyers need to evaluate polycarbonate versus glass across 7 critical dimensions. Bakway Advanced Material Co., Ltd., an IATF 16949 certified polycarbonate sheet manufacturer, supplies solid and multiwall sheets to clients in 40+ countries. Request a quote for solid polycarbonate sheets with custom thickness and UV coating options.
Impact Resistance: 250× vs. One Stone Strike
ASTM D256 (Izod notched impact) measures polycarbonate at 600–850 J/m versus 2–3 J/m for annealed glass — roughly 250 times less. A 25 mm steel ball dropped from 2 meters shatters 6 mm glass but bounces off 6 mm polycarbonate with zero damage (ISO 180/A). Tempered glass absorbs 10–15 J/m, but its failure mode disintegrates into thousands of fragments. Polycarbonate’s ductile deformation absorbs energy without generating sharp shards — critical for machine guarding per ISO 23125. Bakway provides CNC-machined polycarbonate panels cut to OEM specifications.
Impact Performance Comparison
| Property | Annealed Glass (6 mm) | Tempered Glass (6 mm) | Solid PC (6 mm) |
|---|---|---|---|
| Izod Impact (ASTM D256) | 2–3 J/m | 10–15 J/m | 600–850 J/m |
| Failure Mode | Sharp shards | Small fragments | Ductile deformation |
| 25 mm Steel Ball Drop (2 m) | Shatters | Shatters | No damage |
| Machine Guarding Suitability | Not approved | Limited use | Approved (ISO 23125) |
Weight Reduction: Half the Structural Load
Glass has a density of 2.5 g/cm³, polycarbonate 1.2 g/cm³ — less than half the weight. A 2 m × 1 m × 6 mm panel weighs 30 kg in glass versus 14.4 kg in polycarbonate. For a greenhouse with 20 such panels, that is 300 kg of dead load saved per EN 1991-1-1 (Eurocode 1). In stadium canopies and atria roofs, accumulated weight savings reduce structural steel costs by 15–20% versus glass. Multiwall polycarbonate reduces weight further: 10 mm twin-wall sheets weigh only 1.7 kg/m². Explore multiwall sheet specifications for lightweight roofing solutions.
Thermal Insulation: The U-Value Economics
Single-pane 6 mm glass has a U-value of 5.7 W/m²·K (EN 673). Solid 6 mm polycarbonate achieves 5.2 W/m²·K. The real advantage is multiwall: a 10 mm twin-wall sheet delivers 3.1 W/m²·K (EN 12667), and 25 mm triple-wall reaches 1.9 W/m²·K. To match this with glass requires double-glazed low-E units (U-value ~2.8 W/m²·K) — 4× heavier and 3× more expensive. For greenhouse operators, a 1 W/m²·K U-value improvement saves approximately USD 1.50–2.50 per m² per year in heating costs (European Environment Agency, EEA Report No 22/2019).
UV Stability: Co-Extrusion vs. Fragility
Glass blocks 95% of UV-B naturally and does not degrade. Standard polycarbonate without UV protection yellows within 2–3 years outdoors (ISO 4892-2). However, co-extruded UV-protected polycarbonate — with a 50 μm UV-absorbing layer molecularly bonded during extrusion — shows less than 3% yellowing index change after 10 years of Florida-equivalent exposure (ASTM G155). Bakway’s exterior-grade sheets carry a 10-year yellowing warranty, and the UV layer is integral to the sheet — not a coating that can peel. Glass needs no UV warranty, but it also doesn’t survive the first impact event in an exterior application.
Fire Performance and Thermal Shock
Polycarbonate carries a UL 94 V-2 rating standard, with V-0 grades for electrical enclosures and public transport (EN 45545-2). Glass is Euroclass A1 non-combustible (EN 13501-1). However, glass shatters under thermal shock — a fire hose on a hot glass panel causes catastrophic failure. Polycarbonate accommodates thermal expansion (CTE: 65–70 × 10⁻⁶/K, ISO 11359-2) without fracture, maintaining structural integrity during evacuation.
Optical Clarity: Measurable but Imperceptible
Float glass achieves 89–91% light transmission with haze below 0.5% (ASTM D1003). Optical-grade polycarbonate achieves 88–90% transmission with 0.5–1.5% haze — measurable in a lab, imperceptible to the eye. Where polycarbonate differentiates is scratch recovery: glass scratches permanently and must be replaced; polycarbonate scratches can be polished out. Hard-coated polycarbonate (pencil hardness 2H–3H, ISO 15184) reduces scratch susceptibility by 70%. View anti-scratch hard-coated polycarbonate for demanding optical applications.
Comprehensive Performance Summary
| Dimension | Glass (6 mm) | Tempered Glass (6 mm) | Solid PC (6 mm, UV-Coex) |
|---|---|---|---|
| Weight (2 m × 1 m panel) | 30 kg | 30 kg | 14.4 kg |
| Impact (Izod, J/m) | 2–3 | 10–15 | 600–850 |
| Light Transmission | 89–91% | 89–91% | 88–90% |
| U-Value (W/m²·K) | 5.7 | 5.7 | 5.2 / 1.9 (multiwall) |
| UV Stability (10-year) | No change | No change | <3% YI (co-extruded) |
| Fire Rating | Euroclass A1 | Euroclass A1 | UL 94 V-2 / V-0 |
| Thermal Shock | Shatters | Shatters | No fracture |
| Fabrication Options | Cut only | Cut before temper | Cut, bend, drill, route, polish |
| 10-Year Lifecycle | 2–3× replacement | 1–2× replacement | Single installation |
Fabrication Flexibility: The Hidden Cost Driver
Glass fabrication stops at cutting. Every feature must be designed before tempering — drilling, notching, or polishing afterward is impossible. Polycarbonate can be CNC routed, laser cut, drilled, cold-bent, thermoformed, and edge-polished after sheet production. This eliminates custom glass molds, reduces lead time from 4–6 weeks to 5–7 days, and enables on-site adjustments. Bakway’s 23+ precision processing services — including laser cutting, CNC routing, polishing, and thermoforming — deliver finished components ready for assembly.
Total Cost of Ownership: The 10-Year Calculation
Glass costs USD 12–18/m² for 6 mm annealed float versus USD 22–32/m² for UV-protected polycarbonate. But procurement decisions based on per-square-meter price ignore TCO.
A 100 m² greenhouse roof in a hail-prone region illustrates the gap: glass (tempered) costs USD 13,500 over 10 years — including USD 4,500 in extra structural steel and USD 6,000 in panel replacements. The equivalent polycarbonate installation (10 mm twin-wall) costs USD 5,600 — 58% less — with lighter steel requirements and zero impact-replacement cost, plus ongoing heating savings from superior insulation. Bakway’s location 80 km from Shanghai Port ensures competitive FOB terms for international buyers. Contact Bakway for a TCO comparison tailored to your project.
FAQ: Polycarbonate vs Glass
Q: Does polycarbonate yellow over time like cheaper plastics?
Standard polycarbonate yellows within 2–3 years outdoors. Co-extruded UV-protected polycarbonate — with a 50 μm UV-absorbing layer bonded during extrusion — shows less than 3% yellowing index change after 10 years per ISO 4892-2 testing. Bakway’s exterior-grade sheets carry a 10-year yellowing warranty with the UV layer integral to the sheet structure.
Q: Can polycarbonate match glass clarity for displays?
Optical-grade polycarbonate achieves 88–90% light transmission (haze 0.5–1.5%) versus 89–91% for float glass (haze <0.5%, ASTM D1003). The difference is imperceptible in display cases, retail fixtures, and machine guarding. Glass retains an edge only in museum-grade glazing where absolute clarity and hardness are non-negotiable.
Q: Is polycarbonate more expensive than glass?
Per square meter, yes — USD 22–32 vs. USD 12–18. But 10-year TCO typically favors polycarbonate by 40–60%: lighter weight cuts structural costs, impact resistance eliminates replacements, and superior insulation reduces energy costs. Request a project-specific TCO analysis with your dimensions.
Conclusion
The polycarbonate vs. glass decision is a procurement strategy question. Glass wins on upfront cost in low-risk interior applications. Polycarbonate wins on impact survival (250×), weight reduction (50%), thermal performance (up to 5× with multiwall), fabrication flexibility, and replacement-free 10-year lifecycle. For B2B buyers specifying transparent materials in exterior applications, machine guarding, vehicle glazing, greenhouse roofing, or architectural canopies, the TCO math is unambiguous. Contact Bakway for technical datasheets, free samples, and a competitive quote tailored to your procurement requirements.
Company Profile
Bakway Advanced Material Co., Ltd. is the largest and most professional PC sheet manufacturer in Eastern China, with 40,000㎡ of base sheet production workshop and 15,000㎡ of sheet processing workshop. Located just 80km from Shanghai Port, we offer efficient sea freight worldwide. Our Singapore and Indonesia branches enable direct transshipment globally, saving significant import duties for customers. With IATF 16949, ISO 9001 and ISO 14001 certifications, we provide 23+ precision processing services to clients across 40+ countries. Contact us for free samples and competitive quotes.
References
- ASTM D256 — Standard Test Methods for Izod Pendulum Impact Resistance of Plastics, ASTM International, 2023
- ISO 180:2023 — Plastics — Determination of Izod Impact Strength
- ISO 4892-2:2013 — Plastics — Methods of Exposure to Laboratory Light Sources, Part 2: Xenon-arc Lamps
- EN 12667:2001 — Thermal Performance of Building Materials, CEN
- EN 13501-1:2018 — Fire Classification of Construction Products, CEN
- EN 1991-1-1:2002 — Eurocode 1: Actions on Structures, CEN
- ISO 23125:2015 — Machine Tools — Safety — Turning Machines
- European Environment Agency, EEA Report No 22/2019
- ASTM D1003 — Haze and Luminous Transmittance of Transparent Plastics
