Definition(s)
Void Space
Void space is an enclosed space in the cargo area external to a cargo tank, other than a hold space, ballast space, oil fuel tank, cargo pump-room, pump-room, or any space in normal use by personnel.
Source: Resolution MEPC.119(52), 2004 amendments to the International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk (IBC Code), 15 October 2004. Regulatory guidance, International Maritime Organization