When installing a fire-stop, what is required between the penetrating item and the surface?

When installing a fire-stop, a 1/4 inch bead is required between the penetrating item and the surface. This specific bead size is crucial because it ensures that the fire-stop material adequately fills the annular space, providing an effective barrier to prevent the spread of fire and smoke through openings around fire-rated walls or floors. The 1/4 inch bead allows for sufficient material application to ensure a proper seal while still enabling the product to perform as intended. Adequate sealing is critical for maintaining the integrity of fire-rated barriers, thus adhering to safety codes and best practices in fire protection.