ISO 10239:2025 Annex B Ventilation Calculator

LPG systems ventilation requirements for small craft

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About This Calculator

The ISO 10239:2025 Annex B calculator determines the minimum required effective area of natural ventilation openings for habitable spaces containing LPG (Liquefied Petroleum Gas) appliances. This tool ensures compliance with international safety standards for marine LPG installations.

Ventilation Formula (Annex B)

A ≥ 2200 + 440U + 440F + 650P

Where A = minimum effective area (mm²)

Automatic Calculations

Input appliance ratings and occupancy to automatically calculate minimum ventilation area requirements per Annex B formula.

Multiple Appliances

Calculate ventilation for spaces with unflued appliances, open-flued appliances, and multiple occupants.

Compliance Verification

Instantly verify if your ventilation design meets the minimum 4,000 mm² requirement and ISO 10239:2025 standards.

Project Documentation

Track project information and export calculations for certification and compliance documentation.

Important Notice

This calculator is provided as a design aid for LPG ventilation systems. All LPG installations must be inspected and certified by qualified gas engineers and marine surveyors. Final approval must be obtained from relevant authorities and certification bodies.

ISO 10239:2025 Standard

ISO 10239:2025 specifies the design, installation, and testing requirements for liquefied petroleum gas (LPG) systems on small craft. Annex B provides specific ventilation requirements for habitable spaces containing LPG appliances.

Ventilation Requirements Covered:
  • Natural ventilation calculations for LPG appliances
  • Unflued (open flame) appliance ventilation requirements
  • Open-flued appliance ventilation considerations
  • Occupancy-based ventilation adjustments
  • Minimum effective area requirements (4,000 mm²)
  • High and low-level ventilation positioning
  • Ventilation opening specifications and standards

Who Should Use This Calculator?

Yacht Builders

Design compliant LPG ventilation systems during vessel construction. Ensure all habitable spaces meet ISO 10239 requirements.

Marine Gas Engineers

Calculate required ventilation areas for LPG installations. Verify compliance before system commissioning and certification.

Marine Surveyors

Verify ventilation compliance during surveys and inspections. Generate documentation for certification purposes.

Naval Architects

Integrate proper LPG ventilation requirements into vessel design specifications and general arrangements.

Need Professional LPG System Certification?

While this calculator helps with design calculations, LPG system installations require professional inspection and certification.

Blue Peter Marine provides comprehensive marine gas system services including:

Contact Us for Certification