Confined Spaces 26 Parts Per Million (PPM) Volume measurement of a gas concentration (parts of a contaminant per million parts of air). Permit-Required Confined Space (Permit Space) A confined space which has one or more of the following characteristics: • Contains or has the potential to contain a hazardous atmosphere.. • Contains a material with the potential for engulfment of an entrant. • Has an internal configuration such that an entrant could be trapped by inwardly converging walls or a floor which slopes downward and tapers to a smaller cross-section. • Contains any other recognized serious safety or health hazard. Personal Protective Equipment (PPE) Equipment that will help prevent accidents and personal injury. PPE includes hard hats, goggles, face shields, steel-toed shoes, respirators, aprons, gloves, and full body suits. Prohibited Condition Any condition during entry into a permit space that is not allowed by the Entry Permit. Purge Performing a complete air exchange in a confined space prior to entry in order to remove contaminated air and replace it with fresh air. Qualified Person A person designated by the employer, in writing, as capable (by education or training) of anticipating, recognizing and evaluating hazardous substances or other unsafe conditions present in confined spaces. Retrieval System The equipment used for non-entry rescue of persons from permit spaces (includes retrieval line, harness and lifting device). Site Survey The process in which the workplace is surveyed for confined spaces, identifying permit spaces and determining whether personnel would need to enter the spaces or not. Stratification The phenomenon of gases forming layers, or stratifying based on weight, especially without normal ventilation in a confined space. This is the reason why atmospheric testing must be performed at various levels to ensure employee safety. Ventilator A machine designed for moving quantities of air. This machine is used to ventilate the confined space prior and during the entry.