Overview
ISO 11485-2:2011 - Glass in building - Curved glass - Part 2: Quality requirements specifies quality limits and measurement methods for curved glass used in building construction, furniture, displays and other non‑automotive applications. It complements ISO 11485-1 (terminology) and the basic product standards for flat glass, and defines tolerances, appearance criteria and test procedures (Clause 4 and Clause 5) for curved annealed, tempered, laminated and insulating glass.
Key topics and technical requirements
- Scope and product types: Applies to curved annealed float, patterned or wired glass, and to curved tempered, heat‑soaked, laminated, coated or insulated assemblies (Clause 4.1).
- Shape, girth and length tolerances (measured per Clause 5.1):
- Shape accuracy ΔP = 2/3·T for thickness < 10 mm; ΔP = 1/2·T for thickness ≥ 10 mm.
- Girth ΔG and length ΔL tolerances: ±2 mm/m for thickness < 10 mm; ±3 mm/m for thickness ≥ 10 mm.
- Edge straightness (ΔR) (Clause 4.3 / 5.2): ΔR ≤ 3 mm/m or 2 mm, whichever is greater.
- Maximum cross‑curve deviation (Clause 4.4 / 5.3): not to exceed 4 mm/m of length.
- Twist deviation (V) (Clause 4.5 / 5.4): size‑dependent limits (e.g., V < 4 mm for L ≤ 1 200 mm up to V < 8 mm for L > 2 400 mm).
- Appearance criteria (Clause 4.6 / 5.5):
- No cold cracking.
- Chipping limits differ for covered vs exposed edges; tong marks allowed only within specified edge zones (≤ 8 mm for ≤ 6 mm thickness; thickness + 2 mm for > 6 mm).
- Pock marks ≤ 2.0 mm diameter. Ring marks and other defects subject to framing/exposure rules.
- Curved laminated and insulating glass tolerances (Clauses 4.7–4.8): total thickness equals component sums; displacement limits (d ≤ 2 mm or 2 mm/m for laminated; d ≤ 3 mm or 3 mm/m for insulating); insulating total thickness tolerance increased by 3 mm; combined curvature formula for two‑pane IGUs.
Practical applications and users
ISO 11485-2 is used to:
- Define procurement and acceptance criteria for curved glazing.
- Guide quality control and laboratory testing at fabricators and inspection bodies.
- Inform design and specification for architects, façade engineers, glazing contractors and façade consultants.
- Support compliance documentation for building projects involving curved glass features.
Typical users: glass manufacturers, fabricators of curved laminated/insulating glass, architects and façade engineers, quality inspectors, and construction specifiers.
Related standards
- ISO 11485-1 - Terminology and definitions for curved glass.
- ISO 16293 (all parts) - Basic soda‑lime silicate glass product requirements referenced for thickness tolerances.
- ASTM C1464 (listed in bibliography) for related bent glass specifications.
Keywords: ISO 11485-2, curved glass quality requirements, tolerances, curved laminated glass, insulating glass, edge straightness, twist deviation, appearance criteria, glass in building.
