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Refrigerant LFL Screening Calculator

Estimate refrigerant charge corresponding to a selected fraction of the lower flammability limit in a simple room-volume screen.

R32, R454B, R1234yf, R290 and R600a presetsEditable LFL valueClear non-compliance disclaimer

Enter the room and refrigerant

This is an LFL-based screening calculation, not a code-compliance charge calculation.

LFL screening

LFL-based screening result

Verify the LFL and all applicable charge-limit rules before design decisions.

Charge at selected LFL fraction—
Room volume—
Selected LFL—
Existing charge concentration—
Existing charge as %LFL—
Review inputs

The entered charge will be compared only with the selected LFL fraction.

Actual permitted refrigerant charge may depend on system type, occupancy, installation height, room geometry, mitigation, ventilation and the adopted edition of applicable standards.
How the tool works

Separate an LFL screen from a standards-based charge calculation

Room volume multiplied by LFL and a chosen fraction is useful for early comparison, but actual permitted charge depends on the adopted standard and installation details.

01

Verify the refrigerant

Use the exact refrigerant and current LFL from the SDS or applicable reference.

02

Calculate room volume

The simple screen assumes a uniform concentration throughout the full entered volume.

03

Apply the correct standard

Occupancy, equipment, installation height and mitigation can change permitted charge.

Room volumeLength × width × height
Screening chargeRoom volume × LFL (kg/m³) × selected fraction
Existing charge %LFLExisting charge ÷ room volume ÷ LFL × 100
Reference sources: US EPA Refrigerant Safety ASHRAE refrigerant classification overview Honeywell R32 product data. Always verify project-specific values against the applicable SDS, instrument manual, standard and site conditions.
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Frequently asked questions

Refrigerant LFL Screening Calculator FAQ

Is this a code-compliance charge limit calculator?

No. It is an LFL-based room-volume screening tool only.

Why can permitted charge differ from this result?

Standards use additional variables such as occupancy, system type, installation height, floor area, mitigation, ventilation and refrigerant characteristics.

Where should I get the LFL value?

Use the current SDS, manufacturer data or the exact edition of the applicable standard.

Can I use the calculator for A1 refrigerants?

A1 refrigerants do not propagate flame under the classification test, so an LFL-based flammability screen is not the relevant charge-limiting method.

Need help applying the result?

Share the target gas, range, environment, equipment format and project quantity to review relevant gas sensors, modules or complete detectors.

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