Which system allows for adjustment and movement between two surfaces without losing the seal?

The correct choice is the Flexible Joint System. This system is designed specifically to accommodate movement between two surfaces while maintaining a secure seal. Such movement can occur due to temperature changes, structural shifts, or general wear and tear. The materials used in a flexible joint are engineered to allow for this flexibility without compromising the integrity of the seal, which is essential in applications where firestopping is critical.

A Mechanical Joint System typically involves rigid components that are fastened together, which would not effectively accommodate movement between surfaces. A Static Joint System is meant for immovable elements, offering no allowance for adjustments or movement. The Thermal Joint System generally deals with the consequences of thermal expansion but does not specifically ensure the maintenance of a seal during movement. In contrast, the Flexible Joint System excels in providing both movement capability and maintaining a firestop seal, which is crucial in fire protection applications.