Calculator Inputs
Suitability Graph
The chart compares calculated suitability scores for common extinguisher agents under the selected conditions.
Example Data Table
| Area | Fire Class | Hazard Level | Electrical | Kitchen | Sensitive Equipment | Suggested Agent |
|---|---|---|---|---|---|---|
| 180 m² | A | Light | No | No | No | Water Mist |
| 260 m² | Multi | Ordinary | Yes | No | Yes | Clean Agent |
| 140 m² | B | Extra | Yes | No | No | CO₂ |
| 95 m² | K | Ordinary | No | Yes | No | Wet Chemical |
| 110 m² | D | Extra | No | No | No | Class D Metal Powder |
Formula Used
Required Coverage Index = (Area ÷ Base Coverage) × Class Multiplier × Hazard Multiplier × Fuel Factor × Travel Factor × Height Factor × Condition Factors
Fuel Factor
Fuel Factor = 1 + (Fuel Load Density ÷ 100)
Travel Factor
Travel Factor = 1 + max[0, (Travel Distance - 15) × 0.015]
Height Factor
Height Factor = 1 + max[0, (Ceiling Height - 3) × 0.035]
Recommended Units
Recommended Units = ceiling(Required Coverage Index)
Minimum Rating Index
Minimum Rating = 2.0 × Class Multiplier × Hazard Multiplier × Fuel Factor × Height Factor
This tool uses an engineering screening model. It combines area, hazard intensity, travel distance, discharge environment, and equipment sensitivity to rank likely extinguisher agents and estimate unit count. It is useful for early planning, comparison studies, and budget estimates, but it does not replace legal code review or certified fire protection design.
How to Use This Calculator
- Enter the protected floor area in square meters.
- Set the maximum acceptable travel distance to an extinguisher.
- Input estimated fuel load density for the space.
- Choose the dominant fire class and overall hazard level.
- Tick conditions like energized equipment, kitchen oils, or poor ventilation.
- Press Calculate Selection to generate the recommended result.
- Review the top agent, capacity range, unit count, and warnings.
- Use the chart and factor blocks to compare engineering tradeoffs.
- Export the result using CSV or PDF for documentation.
FAQs
1. What does this tool actually estimate?
It estimates a practical extinguisher type, suggested capacity range, coverage index, and approximate unit count from engineering inputs such as area, fire class, fuel load, electrical presence, and special conditions.
2. Can this replace local fire code requirements?
No. It is a planning calculator only. Final extinguisher selection, quantity, mounting, and travel distance must follow the locally adopted code, insurer guidance, and a qualified fire protection professional’s review.
3. Why does electrical equipment change the result?
Electrical exposure favors non-conductive agents. That usually raises the ranking of CO₂, clean agent, or dry chemical options and may reduce the suitability of foam in energized environments.
4. Why is wet chemical strongly preferred for kitchens?
Cooking oils and fats behave differently from ordinary combustibles. Wet chemical agents help cool the surface and create a soap-like layer that reduces re-ignition risk.
5. When should Class D agent be used?
Use specialized Class D powder when combustible metals like magnesium, sodium, titanium, or similar reactive materials are present. General-purpose extinguishers are unsuitable for those hazards.
6. Why does poor ventilation reduce CO₂ suitability?
In poorly ventilated spaces, carbon dioxide discharge can introduce safety concerns for occupants and may need stricter controls. The calculator therefore lowers its suitability score in confined conditions.
7. What is the coverage index?
The coverage index is a dimensionless screening value. It scales the protected area with hazard multipliers and site factors, then converts that adjusted demand into an estimated unit count.
8. Why might clean agent rank above dry chemical?
Clean agent usually rises when residue control matters, especially around servers, controls, laboratory instruments, or telecom equipment. It helps reduce cleanup time and secondary equipment damage.