ASTM E1300 Glass Calculator
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Disclaimer
This tool is provided for preliminary engineering assessment and design verification of glass panels under uniform lateral loads per ASTM E1300. It is not a substitute for project-specific structural engineering analysis by a qualified Professional Engineer (P.Eng. / PE).
- Results are based on idealized boundary conditions and material properties. Actual field conditions may affect real-world performance.
- The engineer of record is responsible for verifying model assumptions for the specific project conditions and applicable building code.
- This tool does not constitute a stamped or sealed engineering calculation.
- Allowable stress values are based on a statistical probability of breakage (8/1000 per ASTM E1300). Glass strength is inherently variable.
- Kace Engineering Ltd. assumes no liability for errors, omissions, or consequences arising from the use of this tool.
01 — Panel Geometry
4SS — All Sides
This calculator is limited to rectangular glass panels simply supported on all four edges (4SS). For 2-sided or 3-sided support conditions, please contact Kace Engineering.
02 — Glass Configuration
1 Lite — Monolithic
ℹ Laminated Glass: Laminated glass analysis is not included in this version. Please contact Kace Engineering for laminated glass design assistance.
Running ASTM E1300 calculation…
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ASTM E1300 Glass Check Report
Kace Engineering Ltd.
Structural Glazing
Structural Glazing
Load Resistance
Results
Reference — Abbreviations
| NFL | Non-Factored Load — The base load capacity of a specific glass type and size per ASTM E1300 |
| GTF | Glass Type Factor — Multiplier based on glass heat treatment and load duration |
| LSF | Load Share Factor — Distribution of load between lites in an insulating glass unit |
| LR | Load Resistance — The allowable design load, calculated as LR = NFL × GTF / LSF |
| AN | Annealed — Standard float glass with no heat treatment |
| HS | Heat Strengthened — Glass with approximately 2× the strength of annealed |
| FT | Fully Tempered — Glass with approximately 4× the strength of annealed |
| IGU | Insulating Glass Unit — Two or more glass lites separated by an air space |
| 4SS | Four Sides Simply Supported — Glass supported continuously along all four edges |
Reference — Abbreviations
| NFL | Non-Factored Load: base load capacity per ASTM E1300 |
| GTF | Glass Type Factor: multiplier for heat treatment & duration |
| LSF | Load Share Factor: load distribution between IGU lites |
| LR | Load Resistance: allowable design load (NFL × GTF / LSF) |
| AN | Annealed — standard float glass |
| HS | Heat Strengthened — ~2× annealed strength |
| FT | Fully Tempered — ~4× annealed strength |
| IGU | Insulating Glass Unit |
| 4SS | Four Sides Simply Supported |
DISCLAIMER — Calculations per ASTM E1300-16. Glass must be free of edge/surface damage and properly glazed. All results must be verified by a licensed Professional Engineer. © Kace Engineering.
DISCLAIMER — Calculations per ASTM E1300-16. Glass must be free of edge/surface damage and properly glazed. Assemblies must be rectangular and continuously supported on all four edges. Edge deflection of supporting members shall not exceed L/175. Non-factored load values for laminated glass are representative of 50°C interlayer temperature. All results must be verified by a licensed Professional Engineer. © Kace Engineering.
Version 2.0 — Updated April 2, 2026