Positive pressure personnel suit

Positive pressure personnel suits (PPPS) — or positive pressure protective suits, informally known as "space suits", "moon suits", "blue suits", etc. — are highly specialized, totally encapsulating, industrial protection garments worn only within special biocontainment or maximum containment (BSL-4) laboratory facilities. These facilities research dangerous pathogens which are highly infectious and may have no treatments or vaccines available. They also feature other special equipment and procedures such as airlock entry, quick-drench disinfectant showers, special waste disposal systems, and shower exits.

The PPPS is a sophisticated variety of personal protective equipment (PPE), a type of hazmat suit, which is air-tight and designed for positive pressure to prevent contamination to the wearer even if the suit becomes damaged. BSL-4 cabinets and "Suit Laboratories" have special engineering and design features to prevent hazardous microorganisms from being disseminated into the outside environment. These biosafety suites, where PPPSs are used, are suites of laboratory rooms which are essentially equivalent to large Class III biosafety cabinets in which the interiors of the PPPSs serve as the "outside" environment for workers. Examples include the biocontainment suites at the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) at Fort Detrick, Maryland and the Maximum Containment Facility (MCF) of the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia.

Fresh, filtered air is typically supplied to the interior of a PPPS via overhead tubing. In addition to the physical barrier provided, the positive pressurization offers additional protection in the event of exposure through a defect or puncture in the suit, for if the suit’s integrity is compromised, air will be forced out instead of being sucked in. Extensive training with the PPPS is required to safely pursue research in a PPPS within a biosafety facility.

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Wikipedia