Which of the following statements is true regarding firestop systems?

Firestop systems are essential components in maintaining the integrity of fire-resistance-rated assemblies, and their effectiveness is often quantified by an F rating. This rating indicates the time duration for which a firestop system can prevent the spread of fire through penetrations and joints within walls and floors. An F rating is derived from standardized testing methods that assess the performance of firestop materials under controlled fire conditions. Thus, this statement highlights the importance of firestop systems being rigorously tested for performance, ensuring they meet safety standards in protecting buildings and their occupants from fire hazards.

In contrast, the other statements do not accurately reflect the role and requirements of firestop systems. For instance, firestop systems are commonly required in various types of buildings, including residential ones, to enhance fire safety. They must undergo testing to verify their effectiveness, and their performance is crucial regardless of whether a building is occupied.