Dilution Ventilation Flow Rate Calculator

Estimate the general ventilation airflow required to dilute an evaporating solvent vapor to a selected acceptable airborne concentration.

Formula: Q = (403.3 × 10⁶ × SG × ER × K) ÷ (MW × C)

Specific gravity of solvent (SG) Specific gravity of the liquid relative to water.

Evaporation rate (ER)

pints/hr

Estimated liquid solvent evaporation rate.

Molecular weight (MW)

g/mol

Molecular weight of the contaminant vapor.

Acceptable concentration (C)

ppm

Enter the design concentration. OSHA guidance commonly uses a value below the applicable exposure limit.

Mixing factor (K) A higher factor increases required airflow to account for imperfect mixing. OSHA guidance describes typical values of 2–5.

Required ventilation flow rate —

Enter the required information and select Calculate.

Important: This is a preliminary dilution-ventilation estimate for steady vapor generation. It does not evaluate fire or explosion risk, oxygen deficiency, peak releases, worker proximity, room geometry, or local exhaust needs. Dilution ventilation should not be used for highly toxic contaminants, uncontrolled releases, or processes where local exhaust ventilation is required. Final design should be completed by a competent ventilation or occupational hygiene professional.