Planning guide / clean-agent
Introduction
The clean-agent calculator estimates an agent mass for a total-flooding room scenario from room dimensions, fixed non-permeable deductions, selected agent, concentration, and minimum room temperature. Use it to follow the arithmetic in an early planning conversation or to understand how changes in net volume and the formula inputs affect the indicative mass. The page shows the individual volume, specific-volume, concentration-factor, kilogram, and pound steps.
Measure the protected enclosure’s inside length, width, and height in meters. Enter only fixed, non-permeable volume deductions supported by the project information, select FK-5-1-12 or HFC-227ea, and use the minimum room temperature required by the scenario. The selected agent supplies the page’s common concentration default, which remains editable.
The result is not a system design or a cylinder selection. The calculator assumes sea-level atmospheric pressure and does not assess leakage, enclosure integrity, distribution, nozzle design, hold time, pressure relief, occupant exposure, detection, controls, or manufacturer-listed software. Clean-agent design affects life safety; the on-page disclaimer requires a licensed fire-protection engineer and manufacturer data for final design.
Method / Calculation
How it works
The calculation starts with the gross rectangular volume, the product of the entered inside dimensions. It subtracts the user-entered fixed, non-permeable deductions to create a net volume. The deductions are not inferred from equipment names or a floor plan, so the person using the estimate must document what is included and why.
The selected agent and minimum temperature determine specific volume S. For FK-5-1-12 the calculator uses S = 0.0664 + 0.0002741t m³/kg. For HFC-227ea it uses S = 0.1269 + 0.0005t m³/kg. Here t is the entered temperature in Celsius. The tool rejects a non-positive specific volume because it cannot produce a meaningful mass from that denominator.
The entered design concentration C is represented as a percentage, then converted to a concentration factor C/(100−C). The required mass estimate is net volume divided by specific volume, multiplied by that factor. The displayed pound value is the kilogram result multiplied by 2.20462. Each stage appears in the live trace, which lets a reviewer check both units and substitutions.
The page’s concentration notes identify common defaults and cite EN 15004 and NFPA 2001 context. Those notes do not select the concentration for a hazard, occupancy, enclosure, or jurisdiction. Project-specific design concentration and applicable requirements must come from the responsible engineer and manufacturer data.
Gross volume = room length × room width × room height
Net volume = gross volume − fixed, non-permeable deductions
Specific volume S = 0.0664 + 0.0002741t for FK-5-1-12; S = 0.1269 + 0.0005t for HFC-227ea
Concentration factor = C ÷ (100 − C); agent mass W = (net volume ÷ S) × concentration factor
Pounds = kilograms × 2.20462
- Use the protected enclosure’s inside dimensions in meters and calculate the rectangular gross volume. Keep dimensions from the same enclosure boundary.
- Subtract only documented fixed, non-permeable volume deductions. Record the deduction basis; the calculator does not classify objects or determine whether an item displaces agent.
- Select the agent and enter the minimum room temperature in Celsius. Read the resulting specific-volume equation and value in the formula trace.
- Enter the design concentration as a percentage. Verify the value against the project’s hazard, occupancy, applicable standard, jurisdiction, and the manufacturer’s listed design tool.
- Divide net volume by specific volume, multiply by the concentration factor, and convert the resulting kilograms to pounds. Compare the visible substitutions with the inputs before interpreting the estimate.
- Send the scenario to the licensed fire-protection engineer and manufacturer for enclosure, discharge, hold-time, hardware, and safety review. Do not select storage cylinders from this mass alone.
The page’s cited context is EN 15004 and NFPA 2001, with the visible default notes limited to the values already stated in the calculator. The equations in the app are simplified planning calculations, not a replacement for either standard or a manufacturer’s software.
A complete review must resolve the protected hazard, enclosure leakage, room pressure, piping network, nozzle arrangement, discharge timing, environmental conditions, and personnel safety. None of those outcomes is established by the mass displayed here.
Keep the input record tied to one defined enclosure condition. If a wall, raised floor, ceiling void, door, or fixed item changes the protected boundary, review whether the measured dimensions and any entered deduction still describe the same protected volume. The calculator has one rectangular gross-volume expression and a single deduction field; it cannot distinguish connected spaces or decide how an opening affects agent retention. Note the applicable concentration basis and temperature source alongside the calculation so that a reviewer can reproduce the arithmetic and identify which inputs require the fire-protection engineer’s decision.
Calculation trace / Illustrative inputs
Fully worked example
Illustrative calculation using the page’s defaults: a 10 m × 5 m × 3 m room, no volume deduction, FK-5-1-12, a 5.3% concentration input, and a 20°C minimum room temperature. The example follows the displayed formulas and is not a suppression design.
- Gross volume = 10 m × 5 m × 3 m = 150 m³. With a zero deduction, net volume = 150 m³ − 0 m³ = 150 m³.
- Specific volume = 0.0664 + (0.0002741 × 20) = 0.071882 m³/kg.
- Concentration factor = 5.3 ÷ (100 − 5.3) = 5.3 ÷ 94.7 ≈ 0.0559662.
- Agent mass = (150 m³ ÷ 0.071882 m³/kg) × 0.0559662 ≈ 116.8 kg.
- Pounds = 116.8 kg × 2.20462 ≈ 257.5 lb, using unrounded kilograms for the displayed conversion.
Illustrative calculator result: about 116.8 kg, or 257.5 lb, under the selected default inputs and the page’s simplified formula.
The calculation assumes sea-level pressure and a rectangular net volume. It does not size cylinders, piping, nozzles, discharge, hold time, or safety provisions. Planning estimate only; final design requires a licensed fire-protection engineer using manufacturer-listed software.
Review / Input checks
Common mistakes
- Using exterior room dimensions. The formula expects the protected enclosure’s inside dimensions. Wall thickness or adjacent voids can change the modeled volume, so use the same boundaries that the design review will use.
- Subtracting an unsupported volume deduction. Only documented fixed, non-permeable deductions belong in the entered field. The tool cannot infer an object’s permeability, future configuration, or whether a piece of equipment occupies the relevant volume.
- Treating the default concentration as a design decision. The page supplies common starting values but leaves concentration editable. Verify the target concentration for the actual hazard, occupancy, standard, jurisdiction, and manufacturer method.
- Entering the wrong temperature unit. The specific-volume equations use Celsius. A Fahrenheit value placed in the field changes the specific volume incorrectly; convert the minimum temperature before entering it.
- Using agent mass as a complete system specification. Mass alone does not determine storage arrangement, hydraulics, nozzle locations, discharge time, enclosure integrity, pressure relief, alarms, controls, or occupant safety. Final design requires the applicable specialist and manufacturer data.
Questions / Planning use
Frequently asked questions
What room volume does the calculator use?
It multiplies the entered inside length, width, and height for gross volume, then subtracts the entered fixed, non-permeable deductions. It does not infer irregular geometry or classify objects from a drawing.
Why does minimum temperature change the result?
Temperature is used in the selected agent’s specific-volume equation. A different value changes the denominator in the agent-mass formula. Enter the project’s required minimum room temperature in Celsius and verify it with the design team.
Are the default concentrations mandatory?
No. They are the page’s editable starting values and are described in its existing EN 15004 and NFPA 2001 context. The applicable concentration must be established for the real hazard and project conditions by a qualified designer.
Does the result tell me how many cylinders to install?
No. It estimates a mass only. Cylinder selection, storage arrangement, piping, nozzle layout, discharge time, hold time, enclosure integrity, pressure relief, detection, controls, and life-safety review are outside this calculator.
What does the sea-level assumption mean?
The page applies no altitude correction. A site at a different elevation needs the applicable engineering and manufacturer method rather than an adjustment guessed from this simplified result.
Continue / Related tools
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