Calculation was carried out acc. to formula:

wzór

More information and details - please see Rules for Class and construction of sea-going ships, Part VI, Chapter 11.8

Mechanical ventilation		Natural ventilation
Air flow rate, Q=	_ [m³/h]	Cross-sectional area of vent duct, F=	_ [cm²]
		Diameter of vent duct, d=	_ [cm]