An enclosed space often has limited access points, is difficult to get in and out of, lacks or has limited ventilation and is unsuitable for permanent work.

Examples of enclosed spaces: cargo holds, stairwells and storage areas adjacent to cargo holds, oil tanks, ballast tanks, sewage tanks, water tanks, double hulls, compressor spaces, chain boxes, thruster rooms, containers and carbon dioxide stores.

When combustion is slow and air throughput is low, oxygen is consumed and hazardous gases build up over time. It can also occur in unventilated water tanks, as oxygen dissolves more easily in water than nitrogen. In decomposing organic material where living microorganisms, such as bacteria and fungi, consume the oxygen. In connection with rust formation.

Gas monitoring equipment is designed to detect and warn you of potentially harmful atmospheres in confined spaces. These “early warnings” are there to help you decide whether it is safe to enter an enclosed space, and whether the atmosphere is safe enough for you to continue working inside it.