Select the type of compartment to calculate requirements
Total volume of the compartment in cubic meters
Volume of permanently installed items in cubic meters
Number of petrol engines used for propulsion
Total fuel capacity in liters
Type of fuel tank installation
Formulas
Net Compartment Volume
V_net = V_gross - V_fixed
Natural Ventilation Opening Area (each opening)
A = 3,300 × ln(V / 0.14) mm²
where V is the net compartment volume in m³
Powered Blower Capacity
q_r = 1.5 m³/min (if V < 1 m³)
q_r = 1.5 × V m³/min (if 1 ≤ V ≤ 3 m³)
q_r = 0.5 × V + 3 m³/min (if V > 3 m³)
Calculation Results
Requirements Summary
Key Requirements from ISO 11105:2020:
• Engine compartments require BOTH natural and powered ventilation
• Tank compartments require natural ventilation only (powered not required)
• Exception: Tank compartments with remaining volume < 3L need no ventilation
• Exhaust ducts must originate in lower one-third of compartment
• Supply and exhaust openings separated by at least 600mm (where compartment dimensions permit)
• Minimum duct cross-section: 3,161 mm² (engine) or 1,134 mm² (tank)
• Blowers must operate for 4 minutes before engine start
• All electrical equipment must be ignition-protected per ISO 8846:1990
• Compartments must be separated from habitable spaces with continuously sealed boundaries
⚠ Important Notes:
• Ventilation ducts must be self-draining
• Terminal fittings for flexible ducts must be ≥ 80% of required duct cross-section
• Ventilation openings (louvers, grates) must meet full cross-sectional area requirement
• Intake and exhaust must be separated to minimize recirculation
• For portable tank storage: compartment must be open to atmosphere or naturally ventilated