Non-permit confined space means a confined space that does not contain or, with respect to atmospheric hazards, have the potential to contain any hazard capable of causing death or serous physical harm. Oxygen-deficient atmosphere and atmosphere containing less than 19.5 percent oxygen by volume. Oxygen enriched atmosphere means an atmosphere containing more than 23.5 percent oxygen by volume. Permit system means the employer's written procedure for preparing and issuing permits for entry and for returning the permit space to service following termination of entry. Prohibited condition means any condition in a permit space that is not allowed by the permit during the period when entry is authorized.
Rescue service means the personnel designated to rescue employees from permit spaces.
Testing means the process by which the hazards that may confront entrants or a permit space are identified and evaluated. Testing includes specifying the tests that are to be performed in the permit space. Testing enables employers both to devise and implement adequate control measures for the protection of authorized entrants and to determine if acceptable entry conditions are present immediately prior to and during entry.