A positive pressure enclosure, also known as a welding habitat or hot work habitat, is a chamber used to provide a safe working environment for performing hot work in the presence of explosive gases or vapors. They are commonly used in welding environments and are associated with the offshore oil industry.[1]
A positive pressure enclosure works by providing a constant inflow of breathable air, which in turn causes a continuous outflow of gas from the chamber. This outflow of gas prevents the ingress of explosive gases or vapors that are often present in these work environments. This constant venting of gases from the chamber also serves to purge the air inside the chamber of unwanted gaseous byproducts of the welding process. Most commercial versions of positive pressure enclosures are referred to by their manufacturers as habitats.[2]