A: Generally speaking, a confined space is an enclosed or partially enclosed space that:
Confined spaces can be below or above ground. Confined spaces can be found in almost any workplace. A confined space, despite its name, is not necessarily small. Examples of confined spaces include silos, vats, hoppers, utility vaults, tanks, sewers, pipes, access shafts, truck or rail tank cars, aircraft wings. Ditches and trenches may also be a confined space when access or egress is limited.
Source: Canadian Centre For Occupational Health And Safety