[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.

According to Malaysia's Department of Occupational Safety and Health (DOSH) the ventilation is considered adequate when the number of air changes every hour is not less than 10 under normal conditions (defined as "processes which generate little or no heat, smoke or fume") and no less than twenty ("should there be processes which generate heat, smoke or fume").

[citation needed] The United States Department of Labor OSHA claims that every type of job that raises workers deep core temperature (listed as higher than 100.4 degrees F (38°C)) raises the risk of heat stress, and provides a list of guidelines which might be used to manage work in these environments.

[4] A minimum positive pressure of 0.1 inch of water or 0.00025 bar (equivalent to 25 Pascal or 0.00363 PSI) shall be maintained inside the Habitat enclosure to prevent ingestion of hydrocarbon in the event of leak occurred outside.

For Zone 1 welding habitats this EU Declaration of Conformity must be based on a Notified Body issued EU–Type Examination Certificate for transportable ventilated rooms EN 50381.