Calculate fire size over time using the t-squared fire growth model for slow, medium, fast, and ultra-fast fires.
Input Parameters
Results
--
HRR at Time t
kW
--
Total Energy Released
MJ
--
Time to Reach 1 MW
s
Note: The t-squared model is the standard fire growth model used in NFPA 72 and performance-based fire engineering. Growth rate categories are defined per NFPA 204 and NFPA 72 Annex B.
Reference
Q(t) = alpha * t² [NFPA 72, NFPA 92]
alpha values: Slow=0.00293, Medium=0.01172, Fast=0.04689, Ultra-fast=0.1876 kW/s²
Total Energy E = alpha * t³ / 3 (growth phase)
Time to 1 MW: t = sqrt(1000/alpha)