ISO 7547:2022

Overview

ISO 7547:2022 - "Ships and marine technology - Air‑conditioning and ventilation of accommodation spaces and other enclosed compartments on board ships - Design conditions and basis of calculations" - specifies the design conditions and calculation methods for marine HVAC and ventilation systems in accommodation spaces of seagoing merchant ships. The standard covers typical summer and winter conditions, minimum outdoor air requirements, occupancy guidance and methods to quantify heat gains/losses and airflow. It excludes extremely cold or hot climates outside the stated design limits. Statutory requirements and classification rules may also apply to individual ships.

Key topics and technical requirements

• Design conditions (Section 4):
  • Summer: outdoor +35 °C / 70% RH; indoor +25 °C / 55% RH; engine-room air +45 °C.
  • Winter: outdoor −20 °C; indoor +22 °C.
  • Minimum outdoor air: 0.008 m³/s per person (based on occupancy).
• Occupancy guidance (Section 4.5):
  • Cabin: design capacity; public rooms: seating-based densities; specific values for day-rooms, hospital, gym, offices and machinery control-room.
• Heat gains and losses (Section 5):
  • Calculation of transmission losses/gains per surface using temperature difference, total heat transfer coefficient (k) and surface area; separate treatment for opaque and glazed areas.
  • Coverage of solar heat gain, internal gains from persons, lighting and equipment.
  • Annex B provides thermal conductivities of common construction materials.
• Airflow calculation (Section 6):
  • Volume-based sizing, supply airflow (for air‑conditioning and ventilation), supply temperature, exhaust airflow, and air balance requirements.
• Annexes:
  • Annex A: guidance and good practice for ship ventilation and air‑conditioning.
  • Annex C–E (normative): additional requirements for machinery control-rooms, wheelhouse, and dry provision store rooms.
  • Annex F: requirements for hot‑air heating of wheelhouse windows.
• Normative reference: ISO 80000‑5 (quantities and units - thermodynamics).

Practical applications and users

ISO 7547:2022 is intended for professionals involved in marine HVAC and ship design, including:

• Naval architects and ship designers specifying accommodation HVAC.
• Marine HVAC engineers and system suppliers sizing equipment and ducts.
• Shipyards and installation teams implementing ventilation/air‑conditioning systems.
• Classification societies, flag administrations and regulatory bodies assessing compliance.
• Ship operators and technical managers optimizing onboard environmental control.

This standard provides the basis for accurate heat gain calculations, airflow sizing, and compliance with industry practice for comfortable and safe accommodation spaces on merchant ships.

Related standards

• ISO 80000‑5 (quantities and units - thermodynamics)
• Earlier maritime ventilation standards incorporated into this edition: ISO 8862, ISO 8863, ISO 8864 and ISO 9099

Keywords: ISO 7547:2022, ship ventilation, marine HVAC, air‑conditioning ships, design conditions, heat gain calculations, airflow sizing, wheelhouse ventilation, machinery control‑room.