Final answer:
A Tight-fitting respirator is a type of respiratory inlet covering designed to closely seal with the user's face to ensure inhaled air goes through the filter. It contrasts with loose-fitting respirators and is distinct from powered or supplied air respirators.
Step-by-step explanation:
A respiratory inlet covering that is designed to form a partial seal with the face is typically referred to as a b) Tight-fitting respirator. This type of respirator fits snugly against the user's face to ensure that inhaled air goes through the filter material of the respirator. In contrast, a Loose-fitting respirator does not seal tightly and is not designed to protect against certain airborne contaminants. Additionally, Powered air-purifying respirators use a fan to draw air through the filter to the user, and Supplied-air respirators have a separate air supply that may, for example, support individuals working in environments with inadequate oxygen.
Examples of tight-fitting respirators can be seen in various contexts such as Continuous Positive Airway Pressure (CPAP) devices used for the treatment of sleep apnea, where the mask covers the nose and mouth and is affixed with head straps. Moreover, respiratory systems like the flow-through respiratory system found in birds illustrate an efficient respiration mechanism, albeit not related directly to protective gear. It's important to also understand that air treatment in the nasal passages, including warming and humidifying, serves multiple protective functions for the respiratory system.