Fire Load Calculator
Formula Reference
Total Fire Load = Σ (Mass × Calorific Value) × Combustion Factor (m)Fire Load Density (qf) = Total Fire Load ÷ Floor Area [MJ/m²]
Typical Net Calorific Values
| Wood | ~17.5 MJ/kg |
| Paper / Cardboard | ~16.5 MJ/kg |
| Textiles / Fabric | ~20 MJ/kg |
| Plastics (general) | ~35 MJ/kg (varies 17–46 by polymer type) |
| Rubber | ~32 MJ/kg |
| Foam / Polyurethane | ~35 MJ/kg |
| Hydrocarbon liquids | ~44 MJ/kg |
Typical Occupancy Fire Load Density (reference only)
| Office (80% fractile, EN 1991-1-2) | ~511 MJ/m² |
| Dwelling / Residential | ~500–780 MJ/m² |
| Retail / Shop | ~600–1,000 MJ/m² |
| Storage / Warehouse | often > 1,000 MJ/m² — highly variable by stored goods |
Methodology, interpretation & sources
Purpose. Calculates total fire load and fire load density (MJ/m²) from combustible material inventory, per the method in EN 1991-1-2 (Eurocode 1, Actions on Structures Exposed to Fire), Annex E.
How to use the result. Start with source data you can verify, enter values on a consistent unit and time basis, and record the assumptions used. The main inputs on this page include Floor Area (m²), Combustion Factor, m EN 1991-1-2 recommends 0.8 for cellulosic materials, 1.0 for liquid fuels (complete combustion assumed)., Your Name, Email, Company Name, What Calculator/Tool Do You Need?. Re-run the calculation when those assumptions change rather than carrying an old result forward.
Decision use. Use this tool for preliminary fire-risk or protection planning. Fire protection decisions should be confirmed against the applicable fire code, occupancy, material properties and site-specific emergency arrangements.
Limitations. Actual fire behaviour depends on ventilation, geometry, fuel distribution, ignition sources and protection-system performance; simplified results cannot represent every scenario.
Primary references. Use the current edition/version that applies to your jurisdiction and organization:
Editorial note. Prepared and maintained by Impact Tech Solutions. Editorially updated 28 September 2026. No individual professional credential is claimed on this page; high-consequence, statutory, tax, engineering or health decisions should be independently verified against the current primary source and, where required, a qualified professional.