Heat Radiation from Window to Point
Calculate incident heat flux from a fire compartment window using the solid flame method (ISO 16733-1, SFPE Handbook)
Window Dimensions
Thermal Properties
Heat Attenuation Screen (Optional)
Schematic Diagram — Plan & Elevation
Formula — Solid Flame Method
q'' = εf · σ · F · (Tf⁴ − T∞⁴)
F = (2/π) · [X/√(1+X²) · tan⁻¹(Y/√(1+X²)) + Y/√(1+Y²) · tan⁻¹(X/√(1+Y²))]
where X = a/(2d), Y = b/(2d)
Safety Thresholds
| ≥ 12.5 kW/m² | Spontaneous ignition risk |
| ≥ 4.0 kW/m² | Piloted ignition possible |
| ≥ 1.5 kW/m² | Above safe separation threshold |
| < 1.5 kW/m² | Within safe criteria |
Sprinkler Activation Time Calculator
Calculate sprinkler activation time using Alpert's correlation (SFPE Handbook)
Fire Characteristics
Geometry
Sprinkler Properties
Detector Activation Time Calculator
Calculate detector activation time using Alpert's correlation (SFPE Handbook)
Fire Characteristics
Geometry
Detector Properties
Fire Severity Calculator
Time equivalence using Law, CIB, and Eurocode methods (EN 1991-1-2)
Compartment Geometry
Openings
Fire Load & Lining
Calculation Results
Law Formula
CIB Formula
Eurocode Formula
Note: Results in minutes. Higher thermal inertia improves fire resistance.
Occupant Movement Time Calculator
Evacuation travel & queueing time (Buchanan 2008)
Room Geometry
Exit Configuration
Occupant Parameters
Room & Exit Diagram
Key Formulae
Do = No / (Lr × Wr)
We = W − boundary layer corrections
Tm = Travel Time + Queueing Time
Compartment Fire Burnout Calculator
Ventilation-controlled burn duration (Buchanan 2008)
Fire Cell Geometry
Ventilation Opening
Fuel Properties
Fire Cell 3D View
Formulae
tb = m / ṁb (ventilation controlled)
FDS Mesh Size Calculator
Optimal mesh cell size based on characteristic fire diameter D* (NIST FDS Guide)
Fire Input
Ambient Conditions
Target Cell Size
Formula
D* = [Q / (ρ∞·Cp·T∞·√g)]2/5
Smoke Layer Height Calculator
Smoke descent time to critical height (Drysdale 2011)