Final answer:
The SCBA requires its frame to be checked weekly for signs of deterioration, dirt, and cracks as part of maintenance to ensure proper function and safety.
Step-by-step explanation:
The piece of protective breathing apparatus that requires the frame to be checked weekly for deterioration, dirt, and cracks is the Self-Contained Breathing Apparatus (SCBA). SCBAs are designed with a mask, frame, harness, and air bottle and are widely used by firefighters for protection from smoke inhalation injury. The frame of the SCBA, in particular, must be inspected regularly because any damage or dirt accumulation can compromise the apparatus's effectiveness and the wearer's safety. This routine inspection is part of the maintenance protocol to ensure the equipment functions properly when needed, especially during life-threatening situations where clean air is crucial.