A(n) ________ system is considered a mechanical firestop.

Cementitious systems are material-based firestops that use a poured or troweled mortar compound to fill and harden in penetrations, not a mechanical assembly.

Cable transit systems use interlocking or compression-based modular frames and fill blocks that mechanically seal around cables passing through fire-rated barriers. The fire rating is achieved through the physical compression and engineered geometry of the system components, qualifying it as a mechanical firestop. This mechanical design also allows individual cables to be added or removed while the overall fire rating of the assembly is maintained.

Firestop blocks are passive material inserts placed into openings and are classified as material-based products, not mechanical firestop systems.

Intumescent sheets are reactive, material-based products that expand when heated and rely on a chemical response rather than a mechanical assembly.