Enclosed space means a space which has any of the following characteristics:
1. limited openings for entry and exit;
2. inadequate ventilation; and
3. is not designed for continuous worker occupancy,
and includes, but is not limited to, cargo spaces, double bottoms, fuel tanks, ballast tanks, cargo pump-rooms, cargo compressor rooms, cofferdams, chain lockers, void spaces, duct keels, inter-barrier spaces, boilers, engine crankcases, engine scavenge air receivers, sewage tanks, and adjacent connected spaces. This list is not exhaustive and a list should be produced on a ship-by-ship basis to identify enclosed spaces.
Source: IMO resolution A.1050(27), Revised recommendations for entering enclosed spaces aboard ships, 21 December 2011, International Maritime Organization. Regulatory Guidance
Source: Resolution MEPC.210(63), 2012 Guidelines for safe and environmentally sound ship recycling, 2 March 2012, International Maritime Organization. Regulatory Guidance
An enclosed space is considered to be any building, room or enclosure, e.g., cabinet, within which, in the absence of artificial ventilation, the air movement will be limited and any flammable atmosphere will not be dispersed naturally.
Source: Rules and Regulations for the Classification of Mobile Offshore Units, Part 7, Safety Systems, Hazardous Areas and Fire, June 2013, Lloyd’s Register, Global Standards