Final answer:
The correct answer is option c. duration of air supply.The correct answer to the question of what limits SCBA's application in confined spaces is option c, duration of air supply, which restricts the time a user can remain in such environments.
Step-by-step explanation:
Self-contained breathing apparatus (SCBA) units are essential in providing breathable air in environments that are oxygen-deficient or contain harmful substances.
They are commonly used in firefighting, industrial settings, and confined space operations. The primary limitation in the context of confined spaces is the duration of the air supply; since SCBAs carry a finite amount of compressed air, users have a restricted time they can remain in the hazardous environment.
This can be especially critical in confined spaces where entry and exit may be time-consuming or difficult. SCBA cylinder size is also a factor, but it is the volume of compressed air and the resultant duration of supply that directly impacts the application in confined space operations.