What Does
Loose-Fitting Facepiece Mean?
A loose-fitting facepiece is a protective respirator apparatus designed to form a partial seal on the face. Its purpose is to ensure that the user is protected from inhaling harmful or hazardous airborne chemicals, including particulates, vapors, and gases.
Unlike a tight-fitting facepiece, loose-fitting facepieces do not depend on a tight seal to protect the wearer. As a result, they have less onerous fit-testing requirements and can be worn by individuals with limited amounts of facial hair.
Loose-fitting facepieces are typically used as part of a supplied-air respirator (SAR) or powered air-purifying respirator (PAPR).
Safeopedia Explains Loose-Fitting Facepiece
The level of protection offered by a loose-fitting respirator depends on the specific design of the respirator. A full facepiece, for instance, is typically designed to protect the face against physical exposures to hazards, while a facepiece that covers just the mouth and nose is used when access to clean air is sufficient.
Because loose-fitting respirators only form a partial seal around the mouth, they will not prevent the inhalation of harmful chemicals unless the area within the respirator is kept at a positive pressure. A positive pressure means that the air pressure inside the facepiece is always greater than the air pressure outside it. This ensures that air will only ever flow outward from the facepiece (never inward), preventing the inhalation of any toxins.
When used with a supplied-air respirator, this type of facepiece does not need the ability to filter toxins, as it is designed to ensure that toxins will never breach the facepiece’s partial seal. This is useful for situations in which it is not possible to confirm what hazards are present in the environment, as no single type of filter is capable of neutralizing every type of chemical hazard. Loose-fitting facepieces may also be worn with powered air-purifying respirators, which eliminate toxins by forcing air through a filter or cartridge.
OSHA describes the efficacy of respirators in terms of their assigned protection factor (APF), which ranges from 0–1,000. The default APF rating of a loose-fitting powered air-purifying respirator is 25, which means that the respirator reduces the concentration of inhaled toxins to 1/25th of the surrounding atmosphere. This APF rating may be increased if the manufacturer can demonstrate that the respirator actually provides a higher degree of protection.