What type of firestop system would be used to protect joints between two different building elements?

A joint firestop system is specifically designed to protect the joints between different building elements, making it the appropriate choice for this scenario. These systems are critical in maintaining fire resistance in areas where two structural components meet, such as walls and floors or different types of walls.

The function of a joint firestop system is to ensure that fire does not spread through these joints, which are often vulnerable points in a building's fire protection strategy. They can accommodate movement as a result of thermal expansion or structural shift, while still providing the necessary barrier to fire.

In contrast, penetration firestop systems are designed to seal openings created by pipes, ducts, or cables that pass through fire-rated walls or floors. A perimeter fire containment system focuses on the area around exterior curtain walls, while through-penetration systems are similar to penetration systems but typically refer to larger openings for significant penetrations in fire-resistive assemblies. Each of these alternatives serves different purposes within firestop design, highlighting the unique role of joint firestop systems in addressing the specific challenge of protecting joints between building elements.