What does percent fill represent in the context of penetrations?

Percent fill in the context of penetrations specifically refers to the proportion of the filled area relative to the opening itself. In other words, it quantifies how much of the opening is occupied by cables, pipes, or other materials in comparison to the overall size of that opening. Understanding percent fill is crucial for ensuring that firestop systems are installed correctly and effectively, as firestop materials must be applied according to specific fill ratios to maintain their fire-resistance ratings.

In this scenario, the correct choice reflects this concept by illustrating the relationship between the number of cables and the area of the opening. Proper management of the percent fill is essential for adhering to fire protection standards and ensuring that all penetrations maintain their integrity in preventing the spread of fire and smoke.

The other choices do not accurately define percent fill: some of them refer to other aspects of installation requirements or are related to firestop products generally but do not focus on the specific measurement of how filled an opening is. Understanding the accurate definition, as indicated in the correct answer, helps clarify how to approach firestop installation in practical applications.