The provisions of this section of Part 8 in the 2002 BSS Standards are mandatory for non-private boats where applicable.

Adequate ventilation is essential for personal health and safety and for the correct and efficient operation of oxygen consuming appliances.

Room-sealed appliances have their own air supply built into the flue ductwork, but other appliances take their combustion air supply directly from the cabin space.

Insufficient ventilation can lead to the production of carbon monoxide, which is highly poisonous. The responsibility for the safety of the occupants on board lies with the boat's owner and on non-private boats, adequate fixed ventilation is required where LPG or other fuel-burning appliances are used that draw air from the accomodation space.

The recommended amount of ventilation depends on the number and type of appliances on board in accordance with the formula from British Standard Code of Practice PD 5482-3 i.e:

minimum effective area (mm2) = [2200xU]+[650xP]+[440xF] Where: U = total input rating (kW) for all appliances (including cookers) without flues F = input rating (kW) for all open or closed flue appliances P = number of people for which the compartment is designed

The input rating for your appliances can normally be found on the manufacturer's plate on the appliance and/or in the operating instructions. The ventilation requirements then need to be split equally between:

  • high level (ideally cabin roof) and
  • as low as practicable.

Low level venting can be achieved by letting in cold air from vents in doors and/or bulkheads, or by means of ducting from a higher level.

Ventilators should be fixed open on boats which are exclusively used on inland waterways, however boats which go out to sea and are likely to experience severe weather conditions may have ventilators that can be closed for weathertightness. Where closable ventilators are used on your boat it's a good idea to make use of a warning notice close to every appliance, e.g. “Warning - open ventilator(s) before use”. [8.9]