ISO 1288-1:2016

Overview

ISO 1288-1:2016 - "Glass in building - Determination of the bending strength of glass - Part 1: Fundamentals of testing glass" defines the fundamental principles for measuring the bending strength of monolithic glass used in building applications. This part explains the rationale behind different test methods, limitations of those methods, safety and calibration considerations, and the factors that influence measured glass strength. Note: testing of insulating units and laminated glass is excluded from this part of ISO 1288.

Keywords: ISO 1288-1, bending strength of glass, glass testing, glass in building, monolithic glass.

Key topics and technical requirements

• Scope and exclusions

  • Applies to monolithic flat and channel-shaped glass for building use.
  • Excludes insulating units and laminated glass.

• Factors affecting bending strength

  • Surface condition (handling damage and micro-cracks are primary strength influencers).
  • Rate and duration of loading.
  • Test surface area (area stressed in tension).
  • Ambient medium (stress corrosion cracking and moisture effects).
  • Aging (time since last mechanical treatment).
  • Temperature.

• Terminology and stress concepts

  • Definitions for bending stress, effective bending stress, equivalent bending strength (patterned glass), and profile bending strength (channel glass).
  • Symbols and parameters used in subsequent detailed test methods (F, h, r, σ, etc.).

• Test-method rationale

  • Explains why different procedures are used (e.g., coaxial double ring tests for varying surface areas, four-point bending for supported specimens, channel-shaped glass tests).
  • Discusses elimination or inclusion of edge effects and stress-field analysis.

• Quality, safety and calibration

  • Guidance on calibration of test machines and safety requirements for personnel operating test equipment.

• Statistical intent

  • Test methods are intended to generate large numbers of bending strength values suitable for statistical evaluation of glass strength.

Practical applications - who uses ISO 1288-1

• Glass manufacturers and processors - to understand test principles and how handling affects strength.
• Test laboratories and QC teams - for establishing and validating bending strength testing programs.
• Façade and structural engineers - to interpret strength data for design and risk assessment.
• Certification bodies and regulators - to evaluate conformity and performance claims.
• Research organizations - for studying failure mechanisms, stress corrosion, and statistical strength distributions.

Related standards

• ISO 1288-2 - Coaxial double ring test (large test surface areas)
• ISO 1288-3 - Four point bending (specimen supported at two points)
• ISO 1288-4 - Testing of channel shaped glass
• ISO 1288-5 - Coaxial double ring test (small test surface areas)
• ISO 16293-1 - Definitions and general physical/mechanical properties for soda lime silicate glass

ISO 1288-1 is the fundamentals document that helps users choose and interpret the detailed test procedures in Parts 2–5 and apply bending strength results in design, QA and research.