EN 13501-2 · ASTM E119 · ISO 834
Fire Rated Glass Calculator
EWEI

HEAT TEMPERATURE
VS TIME ANALYSIS

Compare EW and EI glass unexposed-face temperatures against standard fire curves. Based on ISO 834 and hydrocarbon fire scenarios.

ISO 834 Fire Curve
EW — Radiation Control
EI — Full Insulation
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Calculator Controls

Fire Duration60 min
1 min60 min120 min
Fire Scenario
Glass Type
Fire Stage
CRITICAL
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EW Glass
Limits radiant heat to ≤ 15 kW/m². Unexposed face CAN get hot. Good for facades & atriums.
EI Glass
Full insulation. Unexposed face rise ≤ 140°C avg above ambient. Required in escape routes.
Formula

ISO 834: T = 345 × log₁₀(8t + 1) + 20°C  |  EI limit: +140°C avg / +180°C max above ambient  |  EW: typically 60–65% of furnace temp

Furnace / Fire Side
EW — Unexposed Face
EI — Unexposed Face
EI Safety Limit (160°C)
🔥Furnace Temp945°CFire Side
🟧EW Face Temp586°CUnexposed Side
🟦EI Face Temp123°CUnexposed Side
EW Glass
Unexposed Temp586°C
vs Furnace62% of furnace
Rise above 20°C+566°C
Rad. Flux limit≤ 15 kW/m²
InsulationNOT RATED
EI Glass
Unexposed Temp123°C
vs Furnace13% of furnace
Rise above 20°C+103°C
Max allowed rise+140°C avg
CompliancePASS ✓
EW & EI FIRE RATED GLASS CALCULATOR  ·  EN 13501-2 · ASTM E119 · ISO 834 · NBC 2016